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We are creating a synergy among European Health Data Space projects (e.g., IDERHA, EUCAIM, ASCAPE, iHELP, Bigpicture, and HealthData@EU pilot project) via health standards usage thanks to the HSBOOSTER EU Project since they are involved or using standards, and/or designing health ontologies. We compare health-standardized models/ontologies/terminologies such as HL7 FHIR, DICOM, OMOP, ISO TC 215 Health Informatics, W3C DCAT, etc. used in those projects.

Despite initial responsiveness, acquired resistance to both bevacizumab and chemotherapy in metastatic colorectal cancer is universal. We have recently published that in vitro, chronically oxaliplatin resistance upregulates soluble vascular endothelial growth factor receptor 1, downregulates vascular endothelial growth factor, and also promotes c-MET, b-catenin/transcription factor 4, and AKT activation. We tested whether variation in three serum biomarkers such as the natural c-MET ligand (hepatocyte growth factor), soluble vascular endothelial growth factor receptor 1, and vascular endothelial growth factor-A was associated with efficacy in metastatic colorectal cancer patients treated in the prospective BECOX study. Serum levels of vascular endothelial growth factor-A 165 , soluble vascular endothelial growth factor receptor 1, and hepatocyte growth factor were assessed by enzyme-linked immunosorbent assay method basally and every 3 cycles (at the time of computed tomography evaluation) in a preplanned translational study in the first-line BECOX trial in metastatic colorectal cancer patients treated with CAPOX plus bevacizumab. Response was evaluated by routine contrast-enhanced computed tomography by RECIST 1.1 by investigator assessment and by three blinded independent radiologists. Ratios between soluble vascular endothelial growth factor receptor 1/vascular endothelial growth factor-A and hepatocyte growth factor/vascular endothelial growth factor-A were established and variations through time were related to RECIST 1.1 by investigator assessment and independent radiologist. The BECOX trial included 68 patients, and 27 patients were analyzed in the translational trial. A total of 80 RECIST 1.1 evaluations were done by investigator assessment and 56 by independent radiologist. We found that a 3.22-fold increase in soluble vascular endothelial growth factor receptor 1/vascular endothelial growth factor-A by investigator assessment and a 3.06-fold increase in soluble vascular endothelial growth factor receptor 1/vascular endothelial growth factor-A by independent radiologist from previous determination were associated with responses compared with 1.38-fold increase by investigator assessment and 1.59 by independent radiologist in non-responders (p = 0.0009 and p = 0.03, respectively). Responders had a 3.36-fold increase in hepatocyte growth factor/vascular endothelial growth factor-A from previous determination by investigator assessment and 3.66-fold increase in hepatocyte growth factor/vascular endothelial growth factor-A by independent radiologist compared with 1.43-fold increase by investigator assessment and 1.53 by independent radiologist for non-responders (p = 0.002 and 0.003, respectively). In conclusion, a decrease in vascular endothelial growth factor-A and an increase in soluble vascular endothelial growth factor receptor 1 during chemotherapy and bevacizumab exposure can contribute to both chemotherapy (due to c-MET/b-catenin activation) and bevacizumab (due to low vascular endothelial growth factor requirements) resistance. Because hepatocyte growth factor levels decrease also during acquired resistance, alternative strategies to hepatocyte growth factor-ligand inhibition should be investigated.

Red blood cell distribution width (RDW) is a routine red blood cell count parameter which has been shown to be associated with inflammatory parameters. Recently, some authors proposed that RDW seems to be a marker of an adverse lipidic profile. In order to clarify whether RDW is related to inflammation, plasma lipids, or both, we determined anthropometric, hematimetric, inflammatory and lipidic parameters in 1111 healthy subjects. RDW correlated directly with age, body mass index (BMI), inflammatory parameters (plasma viscosity, erythrocyte sedimentation rate (ESR), fibrinogen, leukocyte and neutrophil count), and inversely with iron and hematimetric parameters (P <  0.05). When subjects were divided according to gender, RDW correlated inversely with triglycerides only in women (P <  0.05). When subjects were classified into RDW-quartiles, increased RDW values were accompanied by decreased serum iron levels and hematimetric indices (P <  0.01), whereas age and inflammatory markers increased according to RDW-quartiles (P <  0.001 and P <  0.05, respectively). However, plasma lipids did not change with increasing RDW-quartiles (P >  0.05). In the linear regression analysis, age, hemoglobin, MCV (beta coefficient: 0.202, -0.234, -0.316, P <  0.001) and fibrinogen (beta coefficient: 0.059, P = 0.048) were the only independent predictors of RDW. The present study indicates that RDW is associated with inflammatory markers and hematimetric indices, but not with plasma lipid levels in a healthy population.

Increased RDW has been found to be a marker of adverse outcomes in cardiovascular disease (CVD), although the exact mechanism remains unclear. Recently, several authors have found that higher RDW is associated with decreased erythrocyte deformability, which can impair blood flow through microcirculation, a fact which may explain the increased risk for CVD events associated with elevated RDW. The aim of the present study was to investigate the association between RDW and erythrocyte deformability in patients with acute myocardial infarction (AMI). The study group comprised 60 AMI patients and 72 gender- and age-matched controls, in whom erythrocyte deformability was determined by means of the elongation index (EI) in a Rheodyn SSD, along with haematological, biochemical and inflammatory parameters. Patients showed higher RDW (p = 0.012) and lower EI (p < 0.05) than controls. When anaemic patients were removed from the study, AMI showed still lower EI than controls (p < 0.05), but no differences in RDW were observed (p = 0.141). RDW correlated inversely with haematimetric indices (p < 0.001), but not with inflammatory and biochemical parameters (p > 0.05). EI correlated inversely with Hb, MCHC (p < 0.001) and directly with MCV (p < 0.05). EI also correlated inversely with glucose (p < 0.05) and directly with HDL-cholesterol (p < 0.05). The multivariate regression model showed that only MCV and Hb were independent predictors of RDW (beta coefficients: -0.383, -0.208; p < 0.001, p = 0.050, respectively). In addition, MCV, MCHC and hyperlipidaemia were independent predictors of EI (beta coefficients: 0.366, -0.533, -0.192; p < 0.001, p < 0.001, p = 0.019 respectively). In AMI patients, increased RDW is not related with EI, so this mechanism does not seem to be responsible for an increased CDV risk in these patients.

Increased red blood distribution width (RDW) in anemia is related to disturbances in the cellular surface/volume ratio, usually accompanied by morphological alterations, while it has been shown in inflammatory diseases that the activity of pro-inflammatory cytokines disturbing erythropoiesis increases RDW. Recently it has been reported that higher RDW is related with decreased erythrocyte deformability, and that it could be related with the association of RDW and increased risk of cardiovascular diseases. In order to analyze the influence of morphological alterations and proinflammatory status on the relationship between RDW and erythrocyte deformability, we analyzed erythrocyte deformability along with RDW and other hematological and biochemical parameters in 36 α-thalassemia, 20 β-thalassemia, 20 δβ-thalassemia trait carriers, 61 metabolic syndrome patients and 76 morbidly obese patients. RDW correlated inversely with erythrocyte deformability in minor β-thalassemia (r =-0.530, p <  0.05), and directly in both metabolic syndrome and morbidly obese patients (ρ= 0.270, p <  0.05 and ρ= 0.258, p <  0.05, respectively). Minor β-thalassemia is often accompanied by more marked cell-shaped perturbations than other thalassemia traits. This could be the reason for this negative association only in this setting. Higher anisocytosis seems to be associated with greater morphologic alterations (shape/volume), which reduce erythrocyte deformability. The proinflammatory profile in metabolic patients can be related to the positive association of RDW with erythrocyte deformability found in these patients. However, further research is needed to explain the mechanisms underlying this association.

Several studies have found an association between hyperuricemia and metabolic syndrome (MS), although there are discrepancies as to which MS components play a pivotal role in this association. We aimed to investigate the association between serum uric acid (SUA) levels and MS in a Mediterranean population (eastern Spain). We performed a case-control study of 71 patients with MS and 122 healthy controls. MS was defined according to the revised National Cholesterol Education Program Adult Treatment Panel III modified criteria. Hyperuricemia was defined as SUA levels >6.55 mg/dL. We determined biochemical, lipidic and inflammatory parameters along with uric acid. Patients with MS showed a higher risk of hyperuricemia than those without MS (OR: 2.87 95% CI: 1.48- 5.55; p = 0.002). In turn, the unadjusted logistic regression analysis showed that hyperuricemia is associated with a higher risk of presenting all the MS components, except hypertension; i.e., hypertriglyceridemia, low HDL-cholesterol, abdominal obesity and glucose intolerance were predictors for hyperuricemia (OR: 3.15, 95% CI: 1.61- 6.15, p = 0.001; OR: 4.07, 95% CI: 1.77- 9.33, p = 0.001; OR: 2.81, 95% CI: 1.41- 5.58, p = 0.003 and OR: 2.82, 95% CI: 1.46- 5.45, p = 0.002 respectively). The adjusted logistic regression analysis revealed that only low HDL-cholesterol and glucose intolerance were independent predictors for hyperuricemia (OR: 2.71, 95% CI 1.06- 6.97, p = 0.038; OR: 2.14, 95% CI 1.01- 4.56, p = 0.049, respectively). In our geographical area, the patients with MS showed a nearly 3-fold risk of hyperuricemia than those without. Among all the MS components, low-HDL-cholesterol and high glucose independently increased more than twice the risk of hyperuricemia, and are the pivotal components involved in hyperuricemia.

It is not well-established whether patients with androgenetic alopecia (AGA) show a higher cardiovascular risk and higher prevalence of metabolic syndrome (MS). Therefore, we aimed to analyze the cardiovascular risk and the prevalence of MS by means of a case-control study. We determined lipidic, inflammatory, hormonal and insulin resistance parameters with conventional laboratory methods in 50 male early-onset AGA patients and 50 controls. AGA patients did not show statistical differences for insulin resistance (glucose, insulin, C peptide, HOMA), lipids (total-cholesterol, HDL-cholesterol, tryglicerides) or hormonal parameters (testosterone, free androgen index, sex hormone-binding globulin) P >  0.05, respectively. No differences between groups were observed in prevalence of MS or its components (P >  0.05). AGA patients showed higher levels of fibrinogen, C-reactive protein (CRP) and lipoprotein(a) (Lp(a)) (P = 0.016, P = 0.019 and P = 0.032, respectively). In the unadjusted logistic regression analyses, PCR >4 mg/L, fibrinogen >395 mg/dL and Lp(a) >59 mg/dL increased the risk of AGA, but in the adjusted logistic regression analyses, only PCR >4 mg/L and Lp(a) >59 mg/dL independently increased this risk (OR = 5.83, 95% CI 1.33-25.59 P = 0.020; OR = 3.94 CI 95% 1.08-14.43 P = 0.038). The present study indicates that AGA patients do not show differences in either insulin resistance or prevalence of MS. However, AGA patients show a higher cardiovascular risk characterised by an increase in inflammatory parameters and Lp(a) levels.

Background: Subclinical hypothyroidism (SCH) has been suggested to be associated with increased cardiovascular risk by different mechanisms. Several cardiovascular risk factors have been analysed, but yielded controversial results., Objectives: We aimed to analyse whether there are differences in several cardiovascular risk markers, such as lipids, inflammatory parameters: plasma viscosity (PV), fibrinogen and C reactive protein (CRP); homocysteine (Hcy) and red blood cell distribution width (RDW), when comparing SCH and controls. We also analysed which of these parameters predict SCH risk and constitute independent markers., Methods: We determined PV in a Fresenius capillary plasma viscosimeter, Hcy by a chemiluminiscent enzyme immunoassay, and biochemical and haematological parameters by conventional laboratory methods in 58 SCH outpatients and 58 controls matched for age and gender., Results: SCH patients did not show statistical differences for glucose, lipids or leucocytes (p > 0.05). However, patients showed a higher prevalence for use of hypolipidaemic drugs, body mass index (BMI), thyroid stimulating hormone (TSH), PV, CRP, fibrinogen, Hcy and RDW (p < 0.05). RDW correlated with inflammation parameters: PV (r = 0.331, p < 0.05), fibrinogen (r = 0.424, p < 0.05), CRP (r = 0.433, p < 0.01) and leucocytes (r = 0.613, p < 0.01). None of the cardiovascular markers correlated with the TSH levels (p > 0.05) In the unadjusted logistic regression analyses, BMI ≥28 kg/m2, RDW ≥14%, Hcy ≥12 μm/L, fibrinogen ≥400 mg/dL and MCV ≤88 fL increased SCH risk, but only RDW ≥14% and fibrinogen ≥400 mg/dL independently increased this risk in the adjusted logistic regression analyses (OR = 4.68, 95% CI 1.20-18.30 P = 0.026; OR = 3.48, 95% CI 1.08-11.23 P = 0.037)., Conclusion: SCH patients show a higher cardiovascular risk, characterised by increased PV, fibrinogen, Hcy and RDW. However, only fibrinogen ≥400 mg/dL and RDW ≥14% are independent predictors of SCH.

The association between hyperhomocysteinemia (HHcy) and Raynaud's phenomenon (RP) remains a matter of debate. In 18 primary RP, 23 secondary RP and 41 controls, we investigated homocysteine (Hcy) levels along with biochemical and inflammatory parameters. The Hcy levels in both primary and secondary RP were elevated when compared with controls (p < 0.05 and p < 0.01, respectively). As age was higher in secondary RP as compared with controls (p < 0.01), both primary and secondary RP were age-matched with a corresponding control group, and with Hcy maintaining its statistical significance (p < 0.05). No differences in creatinine, B12 vitamin or folic acid were observed between groups (p > 0.05), or in the prevalence of cardiovascular risk factors (p > 0.05). When patients were classified according to presence or absence of digital ulcers, as a sign of microangiopathy severity, the former showed higher Hcy levels than the latter (p = 0.035). Our results indicate that both primary and secondary RP patients show a mild increase in Hcy levels, which is not related to age, vitamin deficiencies or impaired renal function, but is related to microangiopathy severity. Therefore the association of HHcy and RP suggest that Hcy may contribute to endothelial dysregulation, which characterizes this disease. Specific studies should be designed to elucidate the pathogenesis of HHcy in these patients.

Red blood cell distribution width (RDW) has been shown to be associated with disease activity in several inflammatory disorders. However only one study to show this has been conducted in patients with Behçet's disease (BD). The aim of the present study was to analyse the association of RDW with BD and its main complications; i.e.; thrombosis and posterior uveitis. A second aim was to analyse the possible correlation between RDW and both haematological and inflammatory parameters. Eighty-nine patients with BD (48 males/41 females) and 94 controls (49 males/45 females) were included in the study. Patients were in an inactive phase of the disease, showing only minimum activity. RDW was statistically higher in patients than in controls (14.02 ± 1.32 vs. 13.15 ± 0.75; p < 0.001) as were CRP, fibrinogen, leucocytes and neutrophils (p < 0.001). No differences in haematimetric indices (MCV, MCH, MCHC) were observed (p > 0.05). RDW correlated negatively with haemoglobin, MCH and MCHC (p < 0.05), and directly with homocysteine (p < 0.01). No correlation was found between RDW and the several inflammatory parameters analysed (p > 0.05). The multivariate regression analysis revealed that haemoglobin and homocysteine were independent predictors of RDW (beta coefficient: -0.310; p = 0.003, beta coefficient: 0.379; p < 0.001, respectively). RDW >14 was associated with neither thrombosis nor uveitis (p = 0.935; p = 0.553, respectively). Our results indicate that BD patients show increased RDW when compared with controls. This increase seems to be related with haematimetric indices and with homocysteine levels. Lack of correlation with inflammatory markers may be due to the fact that patients were in an inactive phase of the disease.

Rheological properties of homozygous sickle cell anaemia (SCA) show marked heterogeneity, which may be explained in part by the concomitance of alpha genotypes or beta haplotypes, along with hydroxurea (HU) treatment. To further clarify this issue, in 11 homozygous patients with SCA in the steady state and in 16 healthy controls, we analysed erythrocyte deformability (ED) in a Rheodyn SSD by means of the Elongation Index (EI) at 12, 30 and 60 Pa, and erythrocyte aggregation at stasis (EA0) and at 3 sec-1 (EA1) in a Myrenne aggregometer along with fibrinogen, biochemical and haematological parameters. When compared with controls, homozygous (SS) patients showed a lower EI at all the shear stresses tested (p < 0.01) and higher EA0 (p < 0.014), but not higher EA1 (p = 0.076). Fibrinogen did not show statistical differences (p = 0.642). In the Spearman's correlation IE60 correlated inversely with Hb S (p < 0.05) and directly with MCV, MCH and Hb F levels (p < 0.01). EA0 correlated inversely with MCV, MCH, Hb F (p < 0.01) and directly with Hb S (p < 0.05). HU treatment improved EI and EA0, but not EA1. This paradoxical behaviour of HU on erythrocyte aggregation merits further research to be clarified.

Raynaud's phenomenon (RP) is an episodic peripheral circulatory disorder characterized by local artery spams in subjects exposed to cold or emotional stress. It is not well-established whether RP patients show an altered rheological profile, mostly due to patient classification and clinical severity. We aimed to compare the hemorheological profile in patients with primary and secondary RP with a healthy control group. Eighteen primary RP, 22 secondary RP and 22 healthy controls, were included in the study. RP patients were also divided according to the presence of digital ulcers (7 with, 33 without). Biochemical and hemorheological variables were analyzed, including glucose, triglycerides, total-cholesterol, immunoglobulins, fibrinogen, plasma viscosity, erythrocyte aggregation, erythrocyte deformability and blood viscosity. Age was higher in secondary RP as compared with primary (p = 0.049), while glucose, triglycerides IgA, IgG and plasma viscosity were higher in secondary RP than in healthy subjects (p < 0.05). RP patients with digital ulcers presented higher IgA (p = 0.012), lower erythrocyte aggregation time (p = 0.008) and a trend for higher fibrinogen levels and plasma viscosity (p = 0.064, p = 0.069, respectively). The results of the present study indicate that secondary RP patients show a mild impairment of the rheological profile that aggravates with microangiopathy severity.

Psoriasis is a systemic inflammatory disorder with increased cardiovascular risk which has been partly attributed to the increased prevalence of the metabolic syndrome (MS). However, the contribution of rheological alterations to cardiovascular risk has been scarcely investigated. In 91 psoriasis patients and in 101 healthy volunteers, we determined the rheological profile (fibrinogen, blood viscosity and erythrocyte aggregation), along with lipidic and inflammatory parameters. Patients showed statistically higher BMI, waist, triglycerides, insulin, c-reactive protein (CRP), neutrophils, lower HDL-cholesterol and a higher MS prevalence (p<0.05). When subjects with MS were excluded from the study, patients with psoriasis still showed a worse inflammatory, lipidic and rheological profile in the above-mentioned variables compared with controls without MS (p<0.05). The logistic regression analysis revealed that abdominal obesity and fibrinogen>384 mg/dL were independent predictors of psoriasis (OR 3.75 95% CI 1.77-7.94, p<0.001; OR 2.95 95% CI 1.14-7.64, p=0.025), respectively. Patients on biologics, showed less inflammation and a better rheological profile than those not on biological treatment. In conclusion, patients with psoriasis show an altered rheological profile, which may contribute to increased cardiovascular risk. Although the presence of MS worsens this profile, psoriasis per se shows rheological alterations due to both inflammation and altered metabolic parameters. Anti TNF-α treatment markedly improves the rheological profile by mostly decreasing inflammation.

Red blood cell distribution width (RDW) is a routine parameter that reflects size variations in erythrocytes. High RDW has been associated with cardiovascular events and inflammatory diseases. However, no studies evaluating the association of RDW with systemic lupus erythematosus (SLE) have been published. We aimed to explore the association of RDW with inflammatory markers in SLE. As SLE is often associated with anaemia, we considered this factor in order to know whether RDW is related with inflammation, anaemia or both in SLE. The study included 105 SLE patients (7 men, 98 women; aged 15-73 years) and 105 controls (9 men, 96 women; aged 18-71 years). Patients were divided according to anaemia status (26 with, 79 without). Biochemical, hematological and inflammatory parameters (C-reactive protein (CRP), fibrinogen and erythrocyte aggregation (EA1)) were analyzed. SLE patients showed increased RDW, CRP and EA1 (p < 0.001), and decreased hemoglobin levels (p < 0.001) when compared with controls. RDW was higher in SLE patients with anaemia (a-SLE) as compared with those without anaemia (na-SLE) (p < 0.01) or controls (p < 0.001). CRP in a-SLE was higher than in controls (p < 0.01) but lower than in na-SLE (p < 0.05). In na-SLE RDW correlated directly with fibrinogen and CRP (p < 0.001), but not in a-SLE. Our results indicate that SLE patients show higher RDW irrespectively of anaemia status, and that RDW is influenced by both anaemia and inflammation, but the influence of anaemia is stronger.

Behçet's disease (BD) is a chronic inflammatory disorder in which thrombosis and posterior ocular involvement occur in about 30% of patients, whose ethiology is unknown. It has not been established whether mean platelet volume (MPV), a marker of platelet activation, is involved in the pathogenesis of thrombotic events and posterior uveitis in these patients. We aimed to analyze whether there are differences in MPV in BD patients when compared with controls and its relation with the presence of thrombosis and posterior uveitis. We determined MPV and platelet count, along with C-reactive protein (CRP) and cardiovascular risk factors (because of their influence on MPV) in 89 BD patients (of which 24 had thrombosis and 23 had posterior uveitis) and 89 sex- and age-matched healthy controls. BD patients showed statistically higher MPV than controls: 10.98 ± 1.19 fL vs. 10.60 ± 1.21 fL (P = 0.044) and higher CRP: 5.9 ± 8.9 mg/L vs. 1.4 ± 1.7 mg/L (P = 0.001). The percentage of hyperlipemia and diabetes was higher in cases than in controls (P = 0.032, P = 0.013, respectively). No differences in MPV were observed when comparing: patients with and without thrombosis: 11.8 ± 1.27 fL vs. 10.94 ± 1.28 fL (P = 0.654); with and without posterior uveitis: 10.76 ± 1.18 fL vs. 11.03 ± 1.30 fL P = 0.398; with CRP and cardiovascular risk factors (P > 0.05). MPV correlated negatively with platelet count (r = -308, P < 0.01), but not with CRP (r = -0.22, P = 0.772). MPV seems to relate to neither thrombosis nor posterior uveitis in BD patients.

It is not well-established whether the alterations that the hemorheological profile undergoes with aging are an effect of concomitant cardiovascular risk factors or are due to age itself. To clarify this issue, we investigated the effect of age on blood rheology in a population of 927 healthy subjects from eastern Spain aged between 16-85 years, divided into four age groups (<30, 30-44, 45-50, ≥60 years) with and without cardiovascular risk factors. We determined blood viscosity, corrected blood viscosity (BVc), plasma viscosity (PV), erythrocyte aggregation (EA), erythrocyte deformability (EEI60) and fibrinogen, along with glucose and plasma lipids. We found that corrected blood viscosity (p = 0.007), plasma viscosity, erythrocyte aggregation, fibrinogen, glucose, and plasma lipids increased with age (p < 0.001). When subjects with cardiovascular risk factors were excluded, the effect of age on blood rheology persisted for all the cited parameters (p < 0.028). EEI60 increased with age (p = 0.033), and it was attributable to a concomitant increase in mean corpuscular volume (p < 0.001). In the Pearson's correlations, age was related to all the parameters analyzed (P < 0.019). The logistic regression analysis revealed that PV ≥1.30 mPa·s, BVc ≥4.90 mPa·s and EA1 ≥8.3 were associated with age ≥60 years (*p = 0.049, *p = 0.013, *p = 0.045, respectively). These results indicate that, although the presence of cardiovascular risk factors influences rheological properties, aging itself is associated with deterioration of rheological blood behavior, mostly related to inflammatory and lipidic changes.

Psoriasis, a systemic immunomediated disorder, is associated with increased cardiovascular risk, although the contribution of rheological alteration to this risk has been seldom analyzed. We have determined erythrocyte deformability in 91 patients with psoriasis and in 101 sex- and age-matched control subjects by means of the Rheodyn SSD, along with hematological, biochemical and inflammatory parameters. Although psoriatic patients showed higher BMI, waist, triglyceride, C-reactive protein levels, neutrophils count and lower HDL-cholesterol (P < 0.001), no differences in the elongation index and in any of the shear stresses tested (12, 30, 60 Pa) were observed (P > 0.05). The results of the present study indicate that patients with psoriasis do not present impaired erythrocyte deformability. Therefore this rheological parameter does not seem to be involved in the higher cardiovascular risk characterizing these patients.

The role played by hemorheological alterations in the development of deep vein thrombosis (DVT) has often been overlooked. Although marked rheological alterations and the relationship with thromboembolic events are well-defined in patients with hematological diseases such as myelom, Waldenström disease and polycythemia vera, the relationship is not so clear in patients without hematological diseases. In the present review, we analyzed studies evaluating the rheological profile in DVT patients. Among the cardiovascular risk factors, only hyperlipidemia, metabolic syndrome, tobacco and obesity increase DVT risk and, in addition, a disturbed rheological profile is shown which could further increase this risk. The significance of hematocrit and fibrinogen, the main factors influencing blood viscosity, is not sufficient to increase blood viscosity in any of the studies analyzed. DVT patients show increased fibrinogen levels and erythrocyte aggregation throughout all the studies despite patients not being in an acute reactant phase. In addition to rheological alterations, it is necessary to consider local conditions at pockets of venous valves which undergo deterioration with aging and play an important role equally to alterations in the rheological profile. Moreover, it is necessary to take into account that systemic rheological alterations are not comparable to those in low shear rate areas where minimum disturbances could be more relevant. It would be convenient to perform multicentric studies with the same rheological methodology and pre-analytical procedures to evaluate, in order to obviate the effect of thrombophilic and circumstantial risk factors, rheological parameters in patients with spontaneous DVT to elucidate their real contribution to the development of thromboembolic events.

HIV-infected patients are at increased cardiovascular risk. Although several studies have analyzed the hemorheological profile in these patients, studies dealing with erythrocyte deformability are scarce. Moreover, studies have been performed in HIV patients on antiretroviral treatment which may influence this rheological parameter. We analyzed erythrocyte deformability (Elongation Index) at 12, 30 and 60 Pa by means of the Rheodyn SSD in 34 naïve HIV-infected patients (22 males and 12 females) and 34 HIV negative control subjects (24 males and 10 females). Erythrocyte indices (MCV, MCH, MCHC), reticulocytes, plasma lipids, iron, folic acid, vitamin B12 and hepatic enzymes were also determined. When compared with controls, naïve HIV-infected patients showed lower total cholesterol, iron, bilirubin and folic acid (p = 0.009, p = 0.003, p = 0.004, p = 0.004, respectively) and higher triglycerides (TG), aspartate aminotransferase (AST) and gamma glutamyl transferase (γGt) levels (p = 0.017, p = 0.042, p = 0.004, respectively). In the multivariate regression analysis, MCV, γGt and triglycerides were independent predictors of EI60. Neither erythrocyte indices nor reticulocyte count showed differences (p > 0.05). No differences in the Elongation Index at any of the shear stresses tested (12, 30, 60 Pa) were found (p > 0.05). The results of the present study indicate that naïve HIV-infected patients not on antiretroviral treatment do not present decreased erythrocyte deformability when compared with HIV negative control subjects.

In patients with acute myocardial infarction (AMI), high red blood cell distribution width (RDW) seems to predict further cardiovascular events, although the mechanism and its possible relation with anaemia and inflammation remains uncertain. We determined in 119 AMI patients before hospital discharge RDW, along with haemoglobin, haematimetric indices and inflammatory parameters (fibrinogen, C-reactive protein, plasma viscosity, neutrophil count). In the follow-up period (21 ± 11 months), 30 patients (25%) developed a recurrent cardiovascular event. In the lineal regression analysis, MCH and neutrophil count were independent determinants for RDW (beta coefficient = -0.544 p < 0.001; beta coefficient: 0.279 p = 0.001, respectively). The logistic regression analysis showed that RDW >14% increases the risk of future events by 6 times; OR 6.19 IC 95% (2.1-18.5); even after adjusting for anaemia, mean corpuscular haemoglobin (MCH) <27 pg/L, fibrinogen >400 mg/dL and neutrophil count >5.7 (103/μL). Our results confirm that RDW, an available and inexpensive measurement reported in routine blood cell counts, seems to be an independent predictor for recurrent cardiovascular events in AMI patients. As we found no association of RDW with either anaemia or inflammatory parameters, the mechanism responsible for increased RDW deserves further research.

Systemic lupus erythematosus (SLE) is characterised by increased venous and arterial thrombotic risk. Nevertheless, how hemorheological alterations contribute to thrombotic risk remains a question of debate. We aimed to determine the rheological profile in 105 patients with SLE (24 with a thrombotic event) and 105 healthy controls. We determined blood viscosity and erythrocyte aggregation along with plasma lipids and fibrinogen. Although SLE patients showed lower blood viscosity at 230 s(-1) at a native hematocrit when compared with controls (p < 0.001), differences disappeared after adjusting the hematocrit to 45% (p = 0.095). When comparing SLE patients with and without thrombotic events, no differences in any rheological parameter were found (p > 0.05), except in fibrinogen which was higher in patients with thrombosis (p = 0.013). No differences in the rheological parameters were observed when venous and arterial thrombotic events were compared, although a tendency for higher fibrinogen was observed in patients with venous thrombosis (p = 0.053). Only hematocrit, fibrinogen and triglycerides were independent predictors of native blood viscosity in the multivariate regression analysis, even after adjusting for continuous variables and for tobacco and hypertension: beta coefficient: 0.727 p < 0.001; beta coefficient: 0.152 p = 0.003 and beta coefficient: 0.133 p = 0.015, respectively. The logistic regression analysis revealed that neither increased native blood viscosity (BVn > 4.33) nor increased erythrocyte aggregation (EA1 > 7.85) increased thrombotic risk: OR 0.636, CI 0.313-3.12, p = 0.578 and OR 2.01, CI 0.77-5.20, p = 0.152, respectively. However, hyperfibrinogenemia (Fbg > 342 mg/dL) increased thrombotic risk by around three times: OR 3.44 CI 1.32-8.96, p = 0.011. Our results suggest that the role of blood viscosity and erythrocyte aggregation in thrombotic risk in SLE patients fails to demonstrate any association.

The association between morbid obesity and hyperhomocysteinemia (HH) remains controversial and the nature of this relationship needs to be clarified as several metabolic, lipidic, inflammatory and anthropometric alterations that accompany morbid obesity may be involved. In 66 morbidly obese patients, 47 women and 19 men aged 41 ± 12 years and 66 normo-weight subjects, 43 women and 23 men, aged 45 ± 11 years, we determined homocysteine (Hcy) levels along with lipidic, anthropometric, inflammatory and insulin resistance markers. In addition, we investigated the effect of Metabolic Syndrome (MS) and its components on Hcy levels. Obese patients had statistically higher Hcy levels than controls: 12.76 ± 5.30 μM vs. 10.67 ± 2.50 μM; p = 0.006. Moreover, morbidly obese subjects showed higher waist circumference, glucose, insulin, HOMA, leptin, triglycerides, fibrinogen, C reactive protein (CRP) (p < 0.001, respectively), and lower vitamin B12 (p = 0.002), folic acid and HDL-cholesterol (p < 0.001, respectively). In the multivariate regression analysis, waist circumference, glucose, leptin and folic acid levels were independent predictors for Hcy values (p < 0.050). When obese patients were classified as having MS or not, no differences in Hcy levels were found between the two groups (p = 0.752). Yet when we analysed separately each MS component, only abdominal obesity was associated with Hcy levels (p = 0.031). Moreover when considering glucose >110 mg/dL (NCEP-ATPIII criteria) instead of glucose intolerance >100 mg/dl (updated ATPIII criteria), it also was associated with HH (p = 0.042). These results were confirmed in the logistic regression analysis where abdominal obesity and glucose >115 mg/dL constitute independent predictors for HH (OR = 3.2; CI: 1.23-13.2; p = 0.032, OR: 4.6; CI: 1.7-22.2; p = 0.016, respectively). The results of our study indicate that increased Hcy levels are related mostly with abdominal obesity and with insulin resistance. Thus, HH may raise atherothrombotic and thromboembolic risk in these patients.

It is not well established whether there is an association among common inherited gene defects, Factor V (FV) Leiden, the prothrombin (PT) G20210A mutation, C677T methylene tetrahydrofolate reductase (MTHFR) and ocular Behçet's disease (BD). We aimed to evaluate the association of these mutations with posterior ocular involvement in 89 BD patients from eastern Spain (48 men and 41 women) of whom 23 had posterior ocular involvement and 66 did not. None of the 23 BD patients with posterior ocular involvement was a carrier of either FV Leiden or the PTG20210A mutation. Only 1 patient was a carrier of the 677TT MTHFR mutation, whereas 4 patients carried FV Leiden, 3 the PTG20210A mutation and 10 the 677TT MTHFR mutation in the group without posterior ocular involvement (p = 0.227, p = 0.556, p = 0.144), respectively. In our geographical area, the commonest thrombophilic mutations do not seem to be related with posterior ocular involvement in BD patients.

Rheological blood behavior in primary Sjögren's syndrome (SS) has been scarcely investigated. We evaluated the rheological profile (blood viscosity, plasma viscosity, erythrocyte deformability, erythrocyte aggregation, erythrocyte aggregation time and erythrocyte disaggregation threshold) along with fibrinogen, high-sensitive C reactive protein, plasma lipids, immunoglobulins, total proteins and erythrocyte sedimentation rate in 22 patients with primary SS (2 males, 20 females, aged 58 ± 9 years) and in 22 healthy volunteers (3 males, 19 females, aged 57 ± 5 years). Patients showed statistically higher plasma viscosity, erythrocyte sedimentation rate and G immunoglobulin (IgG) levels and lower total cholesterol than controls (p = 0.006, p = 0.023, p = 0.034, p = 0.036, respectively). Three patients with extraglandular involvement showed the highest plasma viscosity values: 1.98 cP, 1.70 cP and 1.65 cP, respectively. No differences were observed for the other rheological parameters analyzed. In a multivariate regression analysis, only fibrinogen, triglycerides and IgG were independent determinants for plasma viscosity values (beta coefficient: 0.335; p = 0.001; beta coefficient: 0.242; p = 0.019; beta coefficient: 0.660; p < 0.001, respectively). Our results indicate that patients with primary SS show increased plasma viscosity, mostly related with IgG levels without other alterations in the rheological profile. Further research with a larger sample size achieved by multicenter studies would be desirable.

Hyperhomocysteinemia (HH) and metabolic syndrome (MS) are associated with increased cardiovascular risk. However, whether there is a link between MS or its components and homocysteine levels in a population without cardiovascular disease is not well established. We conducted a case-control study in 61 MS patients (41 males, 20 females, aged 51 ± 11 years) and in 98 controls without MS (59 males, 39 females, aged 50 ± 10 years) to ascertain the association between MS and HH, and with inflammatory markers. MS was classified according to the updated ATPIII criteria [17]. No differences in homocysteine levels were observed when comparing MS patients and controls (12.0 ± 3.18 μM vs. 11.9 ± 3.5 μM, p = 0.829). No association was found between HH (homocysteine >15 μM) and MS, its components (abdominal obesity (p = 0.635), hypertension (0.229), low-HDL cholesterol (p = 0.491), glucose >100 mg/dL (0.485), hypertriglyceridemia (p = 0.490)) or the number of MS components (p = 272). When considering glucose >110 mg/dL (NCEP-ATPIII criteria, 2001) instead of glucose intolerancen >100 mg/dl (updated ATPIII criteria, Grundy, 2005), a borderline association with HH was observed (p = 0.054) of statistical significance (p = 0.008) when glucose >126 mg/dL was considered. In a multivariate regression model, creatinine, folic acid and vitamin B12 were the only independent predictors of homocysteine levels (p < 0.05). Although MS correlated with inflammatory parameters (fibrinogen, hs-RCP, plasma viscosity and leukocyte count, p < 0.001), no association was found between HH and the above-mentioned parameters (p > 0.05). Our results do not indicate a link between SM or its individual components with HH, and diabetes was the only relevant contribution. Cardiovascular disease risk due to MS and HH seems to share no common mechanisms.

Although several studies have been published regarding rheological behaviour of red blood cells in beta and delta-beta thalassaemia traits, little information about erythrocyte deformability in alpha-thalassaemia carriers is available. We aimed to determine erythrocyte deformability in heterozygous (silent, -α/αα) and homozygous (minor alpha-thalassaemia, -α/-α) carriers of the alpha-thalassaemia trait for the alpha 3.7 deletion, the most common in our geographical area. We evaluated erythrocyte deformability by means of the elongation index (EI) in a Rheodyn SSD at 12, 30 and 60 Pa, along with basic haematological cell count, erythrocyte indices, reticulocytes, plasma lipids and iron metabolism parameters in 36 (18 women, 18 men) alpha-thalassaemia carriers (17 heterozygous, 19 homozygous) and 36 healthy subjects (23 women, 13 men). The molecular diagnosis of the alpha 3.7 deletion was evaluated by a PCR-based method. Alpha-thalassaemia carriers presented higher red blood cell counts, RDW-CV (p < 0.001) and lower haemoglobin, MCV, MCH and MCHC (p < 0.001) than controls. EI was statistically lower at 12, 30 and 60 Pa in cases than in controls (p = 0.001, p = 0.002, p = 0.010, respectively). No differences in either elongation indices or haematimetric values were observed when comparing silent heterozygous and minor homozygous alpha-thalassaemia carriers (p > 0.05). Pearson's bivariate correlation showed that EI60 correlated positively with haemoglobin and MCV, MCH, MCHC (p < 0.01), but negatively with ferritin (p< 0.05) and RDW-CV (p< 0.01). In the multivariate regression analysis, MCV (p = 0.001) and haemoglobin (p < 0.001) predicted EI60, with this model accounting for around 43% of variation in EI60 (R2 = 0.427). Alpha-thalassaemia carriers phenotypically showed mild microcytosis and hypochromia, irrespectively of them being silent heterozygous or minor homozygous alpha-thalassaemia carriers, which is associated with decreased erythrocyte deformability.

Background: The pathogenic role of hyperhomocysteinemia in cryptogenic stroke is not well established. We aimed to determine homocysteine levels in patients with cryptogenic stroke considering the possible variables that may act as confounders and analyze the influence of obesity on this association., Patients and Methods: We conducted a case-control study in 123 patients with cryptogenic stroke aged 42 ± 12 years and in 153 control subjects aged 42 ± 13 years. Serum homocysteine was determined by fluorescence polarization immunoassay., Results: Patients showed statistically higher levels of homocysteine, creatinine and higher BMI than controls (p = 0.045, p = 0.014, p = 0.013), respectively. After multivariate adjustment the differences in homocysteine levels disappeared (p = 0.774). When subjects were classified according to the presence or absence of obesity, the differences in the prevalence of hyperhomocysteinemia (homocysteine >15 μM) were highly significant, being higher in patients than in controls (p = 0.009). Likewise, mean values of homocysteine in obese were higher in cases than in controls (16.9 ± 9.5 μM vs. 10.12 ± 2.5 μM; p = 0.020), remaining significant after adjusting for the above mentioned confounders., Conclusion: Although in general, hyperhomocysteinemia does not seem to constitute an independent risk factor for cryptogenic stroke, it significantly increases the risk in obese subjects; therefore it is convenient to decrease its levels in this sub-group to minimize the risk.

There are few studies on haemorheological disturbances in morbidly obese patients. The role played by the metabolic syndrome on the rheological profile of morbidly obese subjects has not yet been established, and it is not clear whether morbidly obese, but "metabolically healthy", show rheological alterations. We aimed to determine the whole rheological profile in 136 morbidly obese patients and 136 normo-weight volunteers, along with plasma lipids, inflammatory and insulin resistance parameters. Patients had statistically higher glucose, triglycerides, HbA1c, leptin, insulin, HOMA, CRP, leucocytes, fibrinogen, plasma viscosity (p < 0.001, respectively), erythrocyte aggregation at 3 s-1 (p = 0.011) and lower erythrocyte elongation index 60 Pa (p = 0.015). In the multivariate regression analysis, the anthropometric, lipidic, insulin resistance and inflammatory parameters predicted haemorheological variables (p < 0.001). No differences were observed for the rheological parameters when morbidly obese subjects with (n = 75) and without (n = 61) the metabolic syndrome were compared (p > 0.05), indicating that the altered rheological profile not only related to the metabolic syndrome, but to obesity itself. When further patients were classified as "metabolically healthy" obese (n = 23) and "metabolically unhealthy" obese (n = 113), the latter presented higher insulin resistance (insulin p < 0.01, HOMA p < 0.05, glucose p < 0.001, triglycerides p < 0.05 and HbA1c p < 0.01) than the former, but no differences in the rheological parameters (p > 0.05) were observed. When "metabolically healthy" obese (n = 23) were compared with "metabolically healthy" controls (n = 81), the former still showed higher HOMA (p < 0.001), triglycerides (p < 0.05), CRP (p < 0.001) and HbA1c (p < 0.05), higher fibrinogen (p < 0.001), plasma viscosity (p < 0.001), erythrocyte aggregation at 3 s-1 (p < 0.05), but a lower erythrocyte elongation index 60 Pa (p < 0.05). Morbidly obese subjects present a more pronounced altered rheological profile in those with metabolic alterations, although the "metabolically healthy" obese also displayed rheological alterations if compared with "metabolically healthy" non-obese controls. These rheological alterations relate to both insulin resistance and inflammation.

The contribution of hemorheological alterations in the prothrombotic condition in patients with metabolic syndrome (MS) remains a question of debate. We aimed to determine the association between MS and hemorheological parameters by means of a case-control study in 61 MS patients and 89 controls without MS. We determined blood viscosity at 230 s(-1) (Brookfield DVIII viscosimeter); plasma viscosity (Fresenius capillary plasma viscosimeter); erythrocyte aggregation at stasis and 3 s(-1) (MA-1 erythrocyte aggregometer); erythrocyte deformability (Rheodyn SSD at shear stresses of 12, 30 and 60 Pascals) and fibrinogen, along with anthropometric, lipidic and inflammatory parameters. MS patients showed increased blood viscosity (p = 0.018), plasma viscosity (p < 0.001), fibrinogen (p < 0.001), erythrocyte aggregation (p < 0.001), and decreased erythrocyte deformability (p = 0.033). In the multivariate regression analysis, fibrinogen and triglycerides predicted plasma viscosity and erythrocyte aggregability, whereas erythrocyte deformability was associated with alterations in the hydrocarbonate metabolism. Blood viscosity related to abdominal obesity. The logistic regression analysis revealed that of all the MS components, only hypertriglyceridemia independently predicts plasma hyperviscosity (OR 3.75 CI 1.44-9.77 p = 0.007) and erythrocyte hyperaggregability (OR 2.41 CI 1.00-5.80 p = 0.050). Erythrocyte hyperaggregability (EA > 8.23) and hyperfibrinogenemia (fibrinogen > 358 mg/dL) were independent predictors of MS: OR 3.34, 95% CI 1.40-7.93, p = 0.006 and OR 2.42 95% CI 1.04-5.66, p = 0.041, respectively. We conclude that MS is associated with an altered hemorheological profile related to inflammatory, lipidic and glucose intolerance parameters which could favor the development of thrombo-embolic and athero-thrombotic events in MS patients.

There is little information regarding the behaviour of red blood cell deformability in macrocytosis. We have determined in 114 patients with macrocytosis (MCV > 97 fL) and in 115 age and sex-matched subjects with normocytosis (VCM < 97 fL) erythrocyte deformability by means of ektacytometric techniques (Rheodyn SSD) measuring the erythrocyte elongation index (EEI) at 12, 30 and 60 Pa. Patients with macrocytosis showed statistically higher EEI at all the shear stresses tested when compared with controls (p < 0.001). When patients with macrocytosis were classified according to their main diagnosis as hepatic or renal disease, HIV and miscellaneous, 66.7%, 41.7%, 36.7% and 33.3% of patients, respectively, showed a EEI 60 higher than 61.8% (mean value of the control group + 2 SD). Linear regression analysis demonstrates that MCV, bilirubin, triglycerides and alanine aminotransferase were the main variables influencing EEI 60. An increased surface/volume ratio of the red blood cells may be the main cause related with a higher erythrocyte deformability in a relevant percentage of macrocytosis. Further research is required to confirm our findings by designing case-control pathology-specific studies.

Although there are several studies dealing with erythrocyte deformability (ED) in obese patients, research on this topic in morbidly obese subjects is scarce. In these studies ED seems to be decreased, although the cause remains unknown. A case-control study in 76 morbid obese subjects (23 women and 53 men, aged 44 ± 13 years) and in 79 normal-weight controls (30 women and 49 men, aged 43 ± 13 years) was undertaken. ED has been determined by ektacytometric techniques in a Rheodyn SSD, by means of the elongation index (EI) at 12, 30 and 60 Pascals, along with anthropometric, lipidic, metabolic and inflammatory parameters. EI was statistically lower in morbidly obese subjects than in controls at all the shear stresses tested (EI12: 47.3 ± 2.14 vs. 47.9 ± 2.07; p = 0.047, EI30: 52.16 ± 2.1 vs. 53.12 ± 1.4; p = 0.007, EI60: 53.9 ± 2.4 vs. 55.2 ± 2.50; p = 0.001) as were anthropometric lipidic and inflammatory parameters (p < 0.001). In the bivariate correlation EI60 correlated negatively with most anthropometric, lipidic and inflammatory parameters. However, in the multivariate analysis, the case-control status was not significantly associated with EI60 and only triglycerides, glucose, hs-CRP and waist circumference were independently associated with EI60, constituting independent predictors of altered ED although, waist circumference, showed the highest statistical significance (p = 0.007). ED is decreased in morbidly obese subjects associated with insulin resistance and inflammation parameters although abdominal obesity seems to be of paramount importance in altering this rheological parameter.

Introduction: There is an association between rheological alterations and lower extremity deep vein thrombosis, although no research has been carried out regarding the possible influence of rheological alterations in the development of venous thrombosis in the upper limbs., Materials and Methods: We have determined in 54 patients (23 male, 31 female; aged 35+/-11 years) with primary upper extremity deep vein thrombosis (UEDVT), and in a well matched control group of 87 subjects (41 male, 46 female; aged 36+/-12 years) the rheological profile (blood viscosity, plasma viscosity, fibrinogen, erythrocyte aggregation, erythrocyte deformability) along with plasma lipids (total cholesterol and triglycerides) and body mass index (BMI). Thrombophilic defects (antithrombin, protein C, protein S deficiencies, factor V Leiden, prothrombin G20210A mutation and antiphospholipid antibodies) were also determined., Results: No statistical differences were observed in any of the rheological parameters analyzed (p>0.05), as well as in plasma lipids and BMI (p>0.05) when cases and controls were compared. In investigating the associated factors, we found that more than 60% of events could be explained through effort (28%), thrombophilic defects (19%) and oral contraceptives (26%). Obesity and hyperlipidaemia were not associated with primary UEDVT., Conclusion: Hemorheological alterations do not seem to contribute from a pathogenic point of view to the development of thrombotic events in this infrequent venous location, which is in accordance both with the absence of cardiovascular risk factors and the high shear forces existing in the upper extremity.

It is not established whether there is an association between erythrocyte aggregation and AB0 blood type, as glycophorins carry sialic acid which is responsible for the negative erythrocyte surface charge and the antigenicity for AB0 blood groups. We have determined erythrocyte aggregation by means of the Myrenne aggregometer in 114 healthy volunteers, along with plasma lipids, fibrinogen and AB0 blood groups. No differences in erythrocyte aggregation (EA0 and EA1) were observed when subjects with 0 (n = 45) and non-0 (n=69) blood group were compared (P = 0.624 and P = 0.838, respectively). Fibrinogen was statistically lower in 0 group compared with non-0 group (P = 0.012). Erythrocyte aggregation (EA0 and EA1) correlated significantly with both lipids and fibrinogen (P < 0.01). When erythrocyte aggregation was dichotomized as EA1 > or = 8, no association was found with 0 and non-0 blood groups (P > 0.05) but it was associated with high lipid levels: T-Chol > 220 mg/dl, TG > 175 mg/dl and high fibrinogen levels > 300 mg/dl (P = 0.035; P = 0.030; P = 0.010, respectively). Erythrocyte aggregation does not seem to be associated with blood groups, but rather with plasma lipids and fibrinogen.

It is not yet known whether Yasmin involves a higher thrombotic risk compared with other contraceptives. We present a serie of eight new cases of women who developed thrombotic events early after starting on Yasmin who were sent to our Thrombosis and Hemostasis Unit for a thrombophilia work-up in the last five years. Only two of them were heterozygous carriers of the prothrombin G20210A mutation and three were obese while none of them were smoker. These new cases provide information about the characteristics of the thrombotic events and the concomitant risk factors, indicating that this pill may not be as safe as had been previously thought, and suggest that new studies regarding safety profile of Yasmin are required to explain the association with venous thrombotic events.

The role played by hemorheological alterations on acute myocardial infarction (AMI) in young patients remains a question of debate. We have carried out a case-control study of 84 AMI patients aged <45 years and 135 sex and age matched controls, in which blood viscosity (BV), plasma viscosity (PV), erythrocyte aggregation (EA) performed with the Myrenne (EA0, EA1) and the Sefam aggregometer (Ta, AI10, gammaD), erythrocyte deformability (ED) along with fibrinogen (Fbg), C-reactive protein (CRP) and plasmatic lipids i.e. total cholesterol (T-Chol) and triglycerides (TG) were determined. AMI patients showed higher, Fbg, TG, EA0, EA1, IA10, gammaD and lower Ta than controls (p=0.029, p<0.001, p=0.013, p=0.003, p=0.010, p=0.025) respectively. No differences in the other rheological parameters were observed. No differences in any rheological parameter were observed regarding the AMI type, number and score of stenosed vessels and the time elapsed since the thrombotic event. After multivariate adjustment, Fbg>380 ml/dl and TG>185 ml/dl were independently associated with a higher risk of erythrocyte hyperaggregability (OR: 5.5 CI 95% 1.04-29.27 and OR: 7.3 CI 95% 2.66-20.03) respectively. EA>8.85 was associated with a increased AMI risk (OR: 5.3 CI 95% 1.98-14.5). These results reinforces the view that in young AMI patients increased Fbg and TG may promote the development of ischaemic events not only through its known mechanism but also by altering rheological blood behaviour, mainly increasing EA.

Atherothrombotic events are significant factors of mortality and morbidity in patients with systemic lupus erythematosus (SLE). The extent that rheological factors may be involved in these events in these patients has not been established. We measured the following rheological parameters in 86 patients with SLE, of whom 16 had suffered venous and/or arterial thrombotic events, and in 86 healthy controls: fibrinogen (Fbg), plasma viscosity (PV), blood viscosity at 230 s(-1) both at native haematocrit (BVn 230 s(-1) and corrected to 45% (BVc 230 s(-1), erythrocyte aggregation at stasis (AE0) and at 3 s(-1) (AE1), aggregation time (Ta), aggregation index at 10 s (AI10), disaggregation threshold (gammaD), and erythrocyte deformability (ED). In addition glucose, total cholesterol (T-Chol), triglycerides (TG), haematocrit (Hct) and Body Mass Index (BMI) were determined. SLE Disease Activity Index (SLEDAI) was also assessed. The patients showed a significant increase in BMI (P=0.030), TG (P<0.001), PV (P=0.007), AE0 (P=0.005), AE1 (P=0.006), AI10 (P=0.024), gammaD (P=0.001), Fbg (P=0.050); and a significant decrease in Ta (P<0.001), Hct (P<0.001) and BVn 230 s(-1) (P=0.003). When patients with SLEDAI10 were compared, the latter had lower Hct (P=0.041) and lower BVn 230 s(-1) (P=0.017) than those with less SLEDAI. No significant differences were found in any of the parameters analysed on comparing patients who had suffered a thrombotic event with those who had not. Our results suggest that, although patients with SLE have moderate rheological changes, these do not seem to be responsible for the increase in the thrombotic tendency in these patients.

The relationship between rheological alterations and systemic sclerosis (SSc) is not well established. We have determined in 27 patients with SSc (4 male, 21 female ) aged 59 +/- 14 years and in a well matched control group the whole rheological profile, i.e. blood viscosity (BV), plasma viscosity (PV), erythrocyte aggregation (EA), erythrocyte deformability (ED) along with fibrinogen (Fbg), C-reactive protein (CRP), lipids, and erythrocyte indices. Patients show higher Fbg, PV and EA (P<0.01) and lower ED (P<0.01). A negative significant correlation was found between ED and inflammation markers, both CRP (P<0.05) and Fbg (P<0.01), indicating that decreased ED seems to be related to inflammatory changes at microcirculatory levels. In addition, patients with anticentromere antibodies show significantly lower ED than those without (P<0.05). The clinical significance of this observation needs to be clarified, deserving further research.

Systemic lupus erythematosus (SLE) is characterised by increased venous and arterial thrombotic risk. Although antiphospholipid antibodies (APAs) have been shown to be related with thrombotic tendency in these patients, in more than 40% of them, thrombosis occurs without the presence of such antibodies. We analysed the association of venous and arterial thrombotic events with acquired (anticardiolipin antibodies (ACAs) and lupus anticoagulant (LA)) and inherited (antithrombin (AT), protein C (PC), protein S (PS) deficiencies, factor V Leiden and the prothrombin G20210A mutation), thrombophilic risk factors in 86 SLE patients and 89 healthy controls. Patients showed a higher significant percentage of ACAs titres IgG>41 GPL u/ml and LA than controls (P=0.009; P<0.001, respectively), although no differences in AT, PC, PS deficiencies, factor V Leiden and prothrombin G20210A mutation was observed (P>0.05). When patients with and without thrombosis were compared, those with thrombosis showed a statistically higher percentage of ACAs IgG>41 GPL u/ml and LA (P=0.048; P=0.001, respectively), OR 4.33; 95% CI 1.01-18.50 and OR 11.57; 95% CI 3.28-40.75, respectively. When venous and arterial thrombotic events were considered separately, the presence of LA constituted a risk factor for arterial thrombosis (P=0.010), OR 11.33; 95% CI 1.86-68.89, as well as for venous thrombosis (P=0.005), OR 10.15; 95% CI 2.12-48.64, while ACAs IgG>41 GPL u/ml on their own, were not associated with arterial or venous thrombosis (P=0.142, P=0.233, respectively). In addition inherited thrombophilic risk factors AT, PC, PS deficiencies, factor V Leiden and PT G20210A mutation do not seem to increase thrombotic risk in SLE patients.

It is not clearly established whether reticulocyte deformability is lower than that of the mature erythrocytes, as most of studies published on this matter have evaluated this rheological parameter by means of micropipette techniques, which are unsuitable for routine measurements. Information is scarce as regards the evaluation of reticulocyte deformability by means of ektacytometry techniques, routinely used in clinical laboratories. We aimed to evaluate erythrocyte deformability (ED), with ektacytometry, in samples of 44 anaemic patients with peripheral reticulocytosis (reticulocytes: (260+/-150)x10(3)/microl) and in 60 healthy non-anaemic volunteers with a normal reticulocyte count (reticulocytes: (60+/-20)x10(3)/microl). We also determined other factors that may influence ED, such as erythrocyte indices (MCV, MCH, MCHC), glucose, total cholesterol and triglycerides. ED was evaluated determining the elongation indices (EI) at 12, 30 and 60 Pa, by means of the Rheodyn SSD. At the three shear stresses tested, patients showed statistically lower EI than controls, higher reticulocyte count, lower cholesterol levels and higher MCHC (P<0.001, respectively). A statistically significant negative correlation (P<0.01) was found between the reticulocyte count and the EI at 12, 30 and 60 Pa (r=-0.643, r=-0.678 and r=-0.692, respectively), and between the EI and the MCHC (correlation coefficients: -0.743, -0.741 and -0.738; P<0.01). As the differences in ED could be attributed partly to alterations in erythrocyte indices and plasma lipid levels, a linear regression analysis was performed, showing that EI is independently associated with the reticulocyte count. Our results suggest that reticulocytes are responsible for the decreased ED observed in anaemic patients with peripheral reticulocytosis, when this hemorheological parameter is evaluated by means of ektacytometry techniques.

Behçet's disease (BD) is a chronic systemic vasculitis characterized by recurrent oral and genital ulcers, uveitis, and skin lesions. It is also associated with an increased risk of developing thrombosis, although the prothrombotic mechanisms are not clearly defined. The role played by rheological alterations in the development of thrombotic events in BD is not well defined, existing little information on whether erythrocyte deformability (ED) may be involved in this issue. Therefore we aimed to evaluate ED by ektacytometric techniques in a large group of patients with BD in a non-active phase of the disease at sampling and in a well-matched control group, in order to establish a possible association between alterations in ED and the presence of thrombotic events. The patient group comprised 45 patients with BD (22 male, 23 female aged 42+/-14 years) and the control group comprised 46 healthy volunteers (23 male, 23 female aged 45+/-13 years). Twelve of the 45 patients with BD had a previous documented history of deep vein thrombosis at least six months before entering the study, and the other 33 did not. Erythrocyte elongation indexes (EI) at the three shear stresses tested (EI12, EI30, EI60) were not statistically different between patients and controls (EI12: P=0.453; EI30: P=0.411; EI60: P=0.403). There were no significant differences in these parameters, either, when patients with and without previous thrombotic events were compared (EI12: P=0.272; EI30: P=0.215; EI60: P=0.171). Our results suggest that ED is not compromised in BD and does not seem to be involved in the development of thrombotic events in these patients.

Behçet's disease (BD) is a chronic systemic vasculitis characterised by recurrent oral and genital ulcers and uveitis, in which 25-30% of patients develop thrombotic events of unknown etiology. In order to ascertain whether erythrocyte aggregation (EA) may be involved in thrombotic events and or uveitis in BD patients, we determined using two erythrocyte aggregometers i.e. Myrenne and Sefam (which provides the total disaggregation threshold, needed for erythrocytes to disaggregate), EA in 77 BD patients (42 male, 35 female, aged 44 +/- 12 years) and 77 controls (41 male, 36 female, aged 43 +/- 11 years). BD patients showed higher EA determined with both aggregometers: Myrenne (EA(0): P = 0.035; EA(1): P < 0.001) or the Sefam (Ta: P < 0.001, AI(10): P < 0.001, gammaD: P = 0.014) as well as higher fibrinogen and triglyceride levels (P < 0.001, P = 0.003, respectively) compared with the control group. However no differences were observed in any of the aggregation parameters determined either with the Myrenne (EA(0), EA(1)) or the Sefam (Ta, AI(10), gammaD) aggregometer when BD patients with thrombotic events (n = 23) or uveitis (n = 21) were compared with those who did not (P > 0.05). These results reinforce previous findings of our group, suggesting that EA does not seem to be involved in thrombotic events or in uveitis in BD patients.

In patients with iron deficiency anaemia (IDA) it has been suggested that the shortened erythrocyte lifespan may be in part due to decreased erythrocyte deformability. In order to know whether erythrocyte deformability is decreased in IDA patients, we have determined the erythrocyte Elongation Index (EI) by means of ektacytometric techniques (Rheodyn SSD, Myrenne Gmbh, Germany), in 50 IDA patients and 100 well age and sex matched healthy controls. At the three shear stresses tested, 12, 30 and 60 Pa, IDA patients show statistically lower EI than controls (37.4+/-6.7 vs 48.6+/-2.9; 45.0+/-6.0 vs 54.5+/-2.8; 48.7+/-5.8 vs 57.0+/-2.9 mPa.s, respectively; p<0.001). A statistically significant correlation was found between EI at 12, 30, and 60 Pa and the hematimetric indices (MCV, MCH and MCHC), suggesting that the alteration in surface/volume ratio (shape) which characterizes this kind of microcytic hypocromic anaemia, accounts in part for the decreased EI. Rheodyn SSD, as an ektacytometric technique, is very sensitive to alterations in red blood cell geometry, for what seems to be a useful tool for detecting diminished erythrocyte deformability in IDA patients.

Fibrinogen is one of the plasmatic proteins which has a major influence on erythrocyte aggregation. The level of fibrinogen at which erythrocyte aggregation does not further increase is not well established. Therefore we aim to determine erythrocyte aggregation with two devices: Myrenne aggregometer (M0 and M1) and Sefam erythro-aggregometer (Ta, AI10 and gammaD) in relation with fibrinogen levels, in patients with several diseases with fibrinogen levels ranging between 200-1100 mg/dl. With the Myrenne aggregometer a plateau can be observed for fibrinogen levels higher than 400 mg/dl, while with the Sefam erythro-aggregometer, aggregation increases proportionally with fibrinogen levels higher than 400 mg/dl. In addition, for fibrinogen values higher than 400 mg/dl, only statististically significant correlations could be observed between fibrinogen and erythrocyte aggregation parameters with the Sefam erythro-aggregometer: r(Ta)=-0.463; r(AI10)=0.624, r(gammaD)=0.817, p<0.01, but not with the Myrenne: r(M0)=0.01, r(M1)=0.02, ns. Although the Sefam erythro-aggregometer is a better tool for determining erythrocyte aggregation both at low and high fibrinogen levels, the Myrenne aggregometer may be useful for assessing the erythrocyte aggregation as an indicator of cardiovascular risk, as in such circumstances fibrinogen levels do not usually exceed values higher than 400 mg/dl.

Some hemorheological parameters constitute risk factors for ischemic cardiovascular events. Most of these hemorheological factors are determined by the erythrocyte intrinsic properties and the high molecular weight plasmatic proteins, especially fibrinogen. The contribution of the plasmatic lipids to hemorheological factors is not well established. With this aim we determined hemorheological parameters in 112 healthy volunteers (62 males, 50 females) aged 35+/-10 years, range 19-54 years, members of our hospital staff. A complete set of rheological test was performed. Blood viscosity (BV) 230 sec(-1), plasma viscosity (PV), erythrocyte aggregation index (EAI), erythrocyte elongation index (EEI), hematocrit and fibrinogen. We also determined plasmatic lipids including total cholesterol (T-Ch) and its fractions (HDL-Ch, LDL-Ch, VLDL-Ch), triglycerides, lipoproteins (Apo B, Apo A(1), B/A(1)). Exclusion criteria were concomitant cardiovascular risk factors or any other associated pathology. Our results show a positive correlation between BV 230 sec(-1) and triglycerides (r=0.335) and negative with HDL-Ch (r=-0.451) (p=0.01), respectively; PV shows a positive correlation with T-Ch (r=0.297), LDL-Ch (r=0.298) and Apo B/A (r=0.290) (p=0.01). The EEI was negatively correlated with TG (p=0.05). Of all the rheological parameters evaluated, EAI is the factor which shows the highest significant correlation with plasmatic lipids: T-Ch (r=0.515), TG (r=0.303), LDL-Ch (r=0.507) and Apo B/A ratio (r=0.403); (p=0.01). These results suggest that plasmatic lipids contribute to modulate the blood rheological properties, slowing blood flow, favouring the development of atherothrombotics events, especially in stenotic areas or bifurcations in the vascular tree., (Copyright 2004 IOS Press)

Behçet's disease (BD) is associated with an increased thrombotic risk, although the prothrombotic mechanisms are not clearly defined. Alterations in blood rheology, specially increased erythrocyte aggregation has been suggested to play an important role in the development of thrombotic events in patients with Behçet's disease. In order to ascertain whether any rheological parameter could be involved in the pathogenesis of thrombotic events in Behçet's disease we have determined plasmatic lipids, fibrinogen, hematocrit, erythrocyte aggregation (Myrenne aggregometer), erythrocyte deformability (Rheodyn SSD), blood viscosity (Brookfield viscosimeter), plasma viscosity (Fresenius capillary viscosimeter) and erythrocyte indexes in Behçet's patients with a non-active disease when sampling, and a well matched control group. The patient group was made up of 40 Behçet's patients (20 male, 20 female aged 43+/-12 years) and the control group comprised 70 healthy volunteers (24 male, 46 female aged 45+/-13 years). Twelve of the 40 Behçet's patients have had a previous documented history of deep vein thrombosis at least six months before entering the study, and the other 28 did not. When patients and controls were compared, patients showed a statistically higher fibrinogen level (p=0.002), plasma viscosity (p=0.003), blood viscosity (p=0.021) and erythrocyte aggregation (p=0.049), the other rheological parameters not being statistically significant. No differences were observed in the rheological parameters when patients with and without a previous thrombotic episode were compared. Our results suggest that rheological alterations do not seem to play any role in the development of thrombotic events in patients with Behçet's disease., (Copyright 2004 IOS Press)