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Patients on anticoagulant treatment are constantly increasing, with an estimated prevalence in Italy of 2% of the total population. The recent spreadout of the COVID-19 pandemic requires a re-organization of Anticoagulation Clinics to prevent person-to-person viral diffusion and continue to offer the highest possible quality of assistance to patients. In this paper, based on the Italian Federation of Anticoagulation Clinics statements, we offer some advice aimed at improving patient care during COVID-19 pandemic, with particular regard to the lockdown and reopening periods. We give practical guidance regarding the following points: (1) re-thinking the AC organization, (2) managing patients on anticoagulants when they become infected by the virus, (3) managing anticoagulation surveillance in non-infected patients during the lockdown period, and (4) organizing the activities during the reopening phases.

Patients on anticoagulant treatment are constantly increasing, with an estimated prevalence in Italy of 2% of the total population. About a quarter of the anticoagulated patients require temporary cessation of direct oral anticoagulants (DOACs) or vitamin K antagonists for a planned intervention within 2 years from anticoagulation inception. Several clinical issues about DOAC interruption remain unanswered: many questions are tentatively addressed daily by thousands of physicians worldwide through an experience-based balancing of thrombotic and bleeding risks. Among possible valuable answers, the Italian Federation of Centers for the diagnosis of thrombotic disorders and the Surveillance of the Antithrombotic therapies (FCSA) proposes some experience-based suggestions and expert opinions. In particular, FCSA provides practical guidance on the following issues: (1) multiparametric assessment of thrombotic and bleeding risks based on patients' individual and surgical risk factor, (2) testing of prothrombin time, activated partial thromboplastin time, and DOAC plasma levels before surgery or invasive procedure, (3) use of heparin, (4) restarting of full-dose DOAC after high risk bleeding surgery, (5) practical nonpharmacological suggestions to manage patients perioperatively. Finally, FCSA suggests creating a multidisciplinary “anticoagulation team” with the aim to define the optimal perioperative management of anticoagulation.

Venous thromboembolism (VTE) is the third most common cardiovascular disease. Interleukins (ILs) and micro-ribonucleic acids (miRNAs) have been proposed as molecules able to modulate endothelial inflammation and platelet hyperactivity. At present, no early biomarkers are available to predict the outcome of VTE. We investigated in a pilot study a selected number of miRNAs and ILs as prognostic VTE biomarkers and reviewed literature in this setting. Twenty-three patients (aged 18–65) with a new diagnosis of non-oncological VTE and free from chronic inflammatory diseases were enrolled. Twenty-three age- and sex-matched healthy blood donors were evaluated as control subjects. Serum miRNAs (MiRNA 126, 155, 17.92, 195), inflammatory cytokines (IL-6, tumor necrosis factor-α, IL-8), and lymphocyte subsets were evaluated in patients at enrolment (T0) and in controls. In VTE patients, clinical and instrumental follow-up were performed assessing residual vein obstruction, miRNA and ILs evaluation at 3 months' follow-up (T1). At T0, IL-8, activated T lymphocytes, Treg lymphocytes, and monocytes were higher in patients compared with healthy controls, as were miRNA 126 levels. Moreover, miRNA 126 and IL-6 were significantly increased at T0 compared with T1 evaluation in VTE patients. Higher levels of MiR126 at T0 correlated with a significant overall thrombotic residual at follow-up. In recent years an increasing number of studies (case–control studies, in vivo studies in animal models, in vitro studies) have suggested the potential role of miRNAs in modulating the cellular and biohumoral responses involved in VTE. In the frame of epidemiological evidence, this pilot study with a novel observational approach supports the notion that miRNA can be diagnostic biomarkers of VTE and first identifies miRNA 126 as a predictor of outcome, being associated with poor early recanalization.

Le patologie emorragiche e trombotiche hanno una presentazione estremamente eterogenea e possono interessare un’ampia fetta di popolazione, come ad esempio nel caso dei pazienti che fanno uso di trattamenti antitrombotici. Il trattamento di queste condizioni richiede la disponibilita di specifiche indagini diagnostiche e della conoscenza clinica delle varie sindromi e del loro trattamento opportuno. Sono pertanto richieste, oltre a una qualificata esperienza clinica, specificita organizzative realizzabili solo in laboratori dedicati con la supervisione di personale esperto. Tale offerta diagnostica-terapeutica non e attualmente disponibile sul territorio nazionale se non in un numero limitato di ospedali di rilevanza nazionale. Sarebbe invece clinicamente molto rilevante per il singolo paziente, e verosimilmente cost-effective per l’insieme del SSN, che si attuasse una disponibilita uniformente distribuita nel territorio nazionale di strutture e/o persone esperte nel campo delle malattie emorragiche e trombotiche. Tale figura professionale non e contemplata dal corrente ordinamento accademico. Il presente documento, coordinato da SISET nel 2012 assieme alle principali societa scientifiche italiane interessate, identifica le conoscenze scientifiche, le competenze professionali e le funzioni all’interno del SSN richieste ad un esperto in emostasi e trombosi, graduate per livelli in funzione della complessita della struttura di appartenenza.

At variance with vitamin K antagonists, the new oral anticoagulants (NOAs) can be prescribed at fixed dosage without adjustment by laboratory testing. However, this does not necessarily mean that the laboratory does not play a role for their management. This position paper represents the consensus document of three Italian scientific societies dealing with laboratory issues in thrombosis and hemostasis. It is aimed at reviewing: 1) which test(s) should be used to evaluate the anticoagulant effect of each of the NOAs presently available (i.e., dabigatran, rivaroxaban and apixaban); 2) the patients to be investigated; and 3) the timing of investigation.

The in vitro and ex vivo antiplatelet effects of 2-amino-1,2-benzisothiazolin-3-one (1) are compared with those of its parent compound 1,2-benzisothiazolin-3-one (2) and with acetylsalicylic acid (ASA) against different agonists. 2-Amino-1,2-benzisothiazolin-3-one inhibits adenosine diphosphate (ADP)-, arachidonic acid (AA)- and collagen-induced human platelet aggregation in vitro, with IC50 values of 8.90 × 10 -5 , 1.50 × 10 -6 and 5.11 × 10 -8 mol/l, respectively. The strong inhibitory activity is significant not only for collagen but also for AA-induced aggregation. The same compound inhibits ex vivo collagenand particularly AA-induced rabbit platelet aggregation at the tested dose of 10 mg/kg i.m. In view of the potential use of 2-amino-1,2-benzisothiazolin-3-one as antithrombotic agent, the log P values for both 1,2- benzisothiazolin-3-one derivatives 1 and 2 are determined, to gain an understanding of the significance of the 2-amino group in the 1,2-benzisothiazolin-3-one moiety with respect to the biological activity under study.

Summary Background Bleeding is the most serious complication of the use of oral anticoagulation in the prevention and treatment of thromoboembolic complications. We studied the frequency of bleeding complications in outpatients treated routinely in anticoagulation clinics. Methods In a prospective cohort from thirty-four Italian anticoagulation clinics, 2745 consecutive patients were studied from the start of their oral anticoagulation (warfarin in 64%, acenocourmarol in the rest). The target anticoagulation-intensity was low (international normalised ratio [INR] ≤2·8) in 71% of the patients and high (> 2·8) in the remainder. We recorded demographic details and the main indication for treatment and, every 3·4 months, INR and outcome events. Such events included all complications (bleeding, thrombosis, other), although only bleeding events are reported here, and deaths. We divided bleeding into major and minor categories. Findings 43% of the patients were women. Nearly three-fifths of the patients were aged 60·79; 8% were over 80. The main indication for treatment was venous thrombolism (33%), followed by non-ischaemic heart disease (17%). Mean follow-up was 267 days. Over 2011 patient-years of follow-up, 153 bleeding complications occurred (7·6 per 100 patient-years). 5 were fatal (all cerebral haemorrhages, 0·25 per 100 patient-years), 23 were major (1·1), and 125 were minor (6·2). The rate of events was similar between sexes, coumarin type, size of enrolling centre, and target INR. The rate was higher in older patients: 10·5 per 100 patient-years in those aged 70 or over, 6·0 In those aged under 70 (relative risk 1·75, 95% CI 1·29–2·39, p vs 6·0 per 100 patient-years) (1·80, 12–2·7, p vs 6·3, 1·75, 1·27–2·44, p 4 5, 7·91, 5·44–11·5, p Interpretation We saw fewer bleeding events than those recorded in other observational and experimental studies. Oral anticoagulation has become safer in recent years, especially if monitored in anticoagulation clinics. Caution is required in elderly patients and anticoagulation intensity should be closely monitored to reduce periods of overdosing.

La terapia anticoagulante e utilizzata per la prevenzione e la cura del tromboembolismo venoso. I nuovi farmaci anticoagulanti (NOA) possono essere somministrati a dosi fisse, senza la necessita di un monitoraggio costante. Tuttavia il laboratorio manterra comunque un ruolo fondamentale nel management di questi farmaci. Questo articolo rappresenta il documento di consenso di tre societa scientifiche italiane che si occupano di diagnostica di laboratorio nell’ambito dell’emostasi e della trombosi. Vengono discussi (i) quali test dovrebbero essere utilizzati per valutare l’effetto di ciascuna molecola disponibile (per es. dabigatran, rivaroxaban e apixaban); (ii) quali pazienti devono essere valutati e (iii) i timing delle analisi.

Summary. In this overview we address the three phase III studies that compared new oral anticoagulants (dabigatran, rivaroxaban and apixaban) with warfarin in the setting of stroke prevention in atrial fibrillation. Strengths and weaknesses of the studies were examined in detail through indirect comparison. We analyze and comment the inclusion and exclusion criteria, the characteristics of randomized patients, the primary efficacy and safety end points and side effects. All new oral anticoagulants resulted in being non-inferior to vitamin K antagonists in reducing stroke or systemic embolism in patients with atrial fibrillation. Dabigatran 150 mg and apixaban were superior to vitamin K antagonists. Importantly, new oral anticoagulants significantly reduced hemorrhagic stroke in all three studies. Major differences among new oral anticoagulants include the way they are eliminated and side effects. Both dabigatran and apixaban were tested in low- to moderate-risk patients (mean CHADS2 [Congestive heart failure, Hypertension, Age, Diabetes, Stroke] score = 2.1–2.2) whereas rivaroxaban was tested in high-risk patients (mean CHADS2 score = 3.48) and at variance with dabigatran and apixaban was administered once daily. Apixaban significantly reduced mortality from any cause. The choice of a new oral anticoagulant should take into account these and other differences between the new drugs.

SummaryTo evaluate the role of low-molecular weight heparin (LMWH) as an alternative to oral anticoagulants in the prevention of recurrent venous thromboembolism, we compared in a randomized trial conventional warfarin treatment with a three-month course of enoxaparin 4000 anti-Xa units once a day subcutaneously. 187 patients with symptomatic deep-vein thrombosis (DVT), diagnosed by strain-gauge plethysmography plus D-dimer latex assay and confirmed by venography in most cases, were treated with full-dose subcutaneous heparin for ten days and then randomized to secondary prophylaxis. During the 3-month treatment period, 6 of the 93 patients who received LMWH (6%) and 4 of the 94 patients on warfarin (4%) had symptomatic recurrence of venous thromboembolism confirmed by objective testing (p = 0.5; 95% confidence interval [Cl] for the difference, -3% to 7%). Four patients in the LMWH group had bleeding complications as compared with 12 in the warfarin group (p = 0.04; 95% Cl for the difference, 4% to 14%). In the 9-month follow-up period, during which 34 patients on warfarin prolonged treatment for other 3 months and 14 up to one year, 10 patients in the enoxaparin group and 4 patients in the warfarin group suffered a documented recurrence of venous thromboembolism. Of these 14 late recurrences, just one occurred in patients with postoperative DVT. After one year there were 16 recurrences (17%) in the LMWH group and 8 (9%) in the warfarin group (p = 0.07; 95% Cl for the difference, 1% to 16%).These results confirm the potential of LMWH as an alternative to oral anticoagulants in this setting, and suggest to evaluate in a prospective study a slightly higher dose of enoxaparin in patients with postoperative DVT.

SummaryDabigatran and other new oral anticoagulants (OAC) represent a step forward in stroke prevention in patients with atrial fibrillation (AF). They indeed have been shown to be an alternative to vitamin K antagonists (VKAs) without the burden of laboratory control. However, these new drugs compete with an effective and well-established therapy, thus bringing about a series of questions and doubts. In this report members of the board of the Italian Federation of Thrombosis Centers (FCSA) answer some questions every clinician might be confronted with.

The diagnostic value of a latex D-dimer test combined with strain-gauge plethysmography (SGP) was assessed in 425 patients referred to our vascular laboratory because of clinically suspected deep-vein thrombosis (DVT) of lower limbs, using venography as the reference standard. The inpatient/outpatient ratio was 236 189 . Adequate venograms were obtained in 401 patients and a DVT was diagnosed in 195 (49%). SGP results were borderline in 38 patients. In the 363 unequivocal cases, sensitivity of SGP was 88% and specificity 90%. The sensitivity of D-dimer latex test was 78% and the specificity 88%. Out of the 363 unequivocal cases, D-dimer test results were discordant with SGP in 88 cases, of whom 60% had DVT and 40% had not, and concordant in 275. The sensitivity of concordant results was 98% ( 124 127 ) and specificity 97% ( 143 148 ). Compared with strain-gauge plethysmography (plus venography in case of borderline results), the combined approach reduced the diagnostic errors (false positive plus false negative results) from 10% ( 40 401 ; 95% confidence interval, 7–13%) to 2% ( 8 401 ; 95% CI, 0.6–3.4%) albeit requiring a greater number of venographies, from 9% ( 38 401 ; 95% CI, 7–12%) to 31% ( 126 401 ; 95% CI, 27–36%). Most calf DVT (94%) were identified. We conclude that this test combination is valuable in the diagnosis of DVT in symptomatic patients, because of the high accuracy of concordant test results. Venography is required in case of borderline or discordant results.

The synthesis of a new compound, 2-amino-1,2-benzisothiazolin-3-one, is described and its antiplatelet activity was studied. A good platelet aggregation inhibitory activity of the tested drug was clearly demonstrated both in vitro and ex vivo, presumably through an effect on arachidonic acid cascade or directly on thromboxane A 2 (TXA 2 ) receptors. An early and long lasting effect on bleeding time has also been observed. The results suggest that 2-amino-1,2-benzisothiazolin-3-one could be a potential antithrombotic agent.

Summary271 patients with acute symptomatic deep venous thrombosis of lower limbs, confirmed by strain-gauge plethysmography and/ or venography, were randomly assigned to receive intermittent subcutaneous heparin calcium or heparin sodium by continuous intravenous infusion for 6–10 days. Heparin dosage was adjusted to maintain activated partial thromboplastin time values (Throm-bofax reagent) at 1.3–1.9 times the basal ones. Strain-gauge plethysmography was repeated at the end of heparin treatment, and evaluation of therapy was performed by comparing the indexes of venous hemodynamics and by assessing the incidence of pulmonary embolism and of bleeding complications.In the intravenous group, Maximal Venous Outflow (MVO) increased from 20.8 ± 12.8 to 28.4 ± 17.5 ml/min per 100 ml of tissue and Venous Capacitance (VC) from 1.39 ± 0.92 to 1.94 ± 1.0 ml/100 ml of tissue (mean ± SD). In the subcutaneous group, MVO increased from 21.0 ± 12.7 to 27.5 ± 18.1 and VC from 1.60 ± 0.86 to 2.06 ± 1.0. The median improvement of MVO and VC were 22% and 36% respectively in the IV group and 20% and 24% in the SC group. Clinical pulmonary embolism occurred in 2 patients in the intravenous group (1 fatal) and in 4 in the subcutaneous group (1 fatal). 9 major bleeding complications occurred in the intravenous group (1 fatal) and 5 in the subcutaneous group (1 fatal). The differences were not significant at the statistical analysis.The results suggest that subcutaneous intermittent heparin has a comparable efficacy to continuous intravenous heparin in the treatment of deep venous thrombosis.To the same conclusion points an overview of the seven randomized trials which compared these treatment modalities.

Hormone replacement therapy is known to increase the risk of thromboembolic events. We compared the effects of HRT and raloxifene on some haemostasis variables.In a multicenter, double-blind study, 54 healthy postmenopausal women were randomized to receive either continuous treatment with 2 mg 17beta-estradiol plus 1 mg norethisterone acetate (n=30) or 60 mg raloxifene (n=24) daily for 12 months. Blood samples were collected at baseline and at 3, 6 and 12 months to evaluate therapy effects on some haemostasis variables (factor VII, factor VIII, prothrombin fragments 1 and 2, protein C, protein C activity, protein S, thrombin-antithrombin complex, D-dimer, antithrombin, fibrinogen and plasminogen activator inhibitor).Both raloxifene and continuous combined hormone therapy modified the haemostasis variables toward a more prothrombotic profile. Factor VIII (p0.01) and fibrinogen (p0.05) plasma levels significantly increased at 6 months, prothrombin fragments 1 and 2 (p0.05) significantly increased at 12 months, whereas protein C activity (p0.001) and antithrombin (p0.01) significantly decreased at 12 months in both groups.Our results demonstrate that raloxifene and continuous combined hormone therapy exhibit the same prothrombotic profile. Both treatments induced an increase in procoagulant parameters at 6 months and a decrease in anticoagulant parameters at 12 months.

The antithrombotic activity of a series of benzopyranopyrimidine derivatives was investigated in platelet-dependent and independent pulmonary thromboembolism in mice. Intraperitoneal subacute treatment with 2-morpholino derivative 3c significantly prevented paralysis due to collagen plus epinephrine-induced pulmonary thrombosis while 2-piperidino substituted derivative 3h significantly protected mice from paralysis caused by thrombin-induced intravascular fibrin formation at dosage not affecting bleeding time. These compounds, previously proved to be effective as antiplatelet agents in vitro, were in vivo more potent as antithrombotics than lysine acetylsalicylate and possessed lower prohemorrhagic activity than the reference drug. Although their ineffectiveness on clotting times, PT and APTT, allows the involvement of coagulation pathways to be ruled out, the mechanisms underlying the favourable benefit risk ratio for these two compounds remain to be further clarified.

To assess the natural history and risk factors for thrombosis in a large cohort of unselected patients with antiphospholipid antibodies.Three hundred sixty consecutive patients (118 males, 242 females, median age 39 years [range 2 to 78]) fulfilling the currently accepted criteria for diagnosis of lupus anticoagulant (LAC) (n = 326) and/or raised immunoglobulin G anticardiolipin antibodies (IgG ACA) (n = 185) were collected from 16 Italian institutions and prospectively observed for a median of 3.9 years (range 0.5 to 5). Main endpoints were the occurrence of arterial or venous thrombosis, the outcome of pregnancies, and any severe complications leading to hospitalization or death.Thirty-four patients developed a thrombotic complication, with a total incidence of 2.5% patient-years. Multivariate logistic regression analysis identified two independent risk factors for thrombotic events: a previous thrombosis (RR 4.9; 95% CI, 1.76 to 13.7; P0.005) and IgG ACA titer above 40 units (RR 3.66; 95% CI, 1.24 to 10.8; P0.01). A total of 28 pregnancies were observed in 25 women and 11 (39%) were abortive. Adverse pregnancy outcomes were significantly more frequent in women with a history of miscarriage or vascular occlusion (9/16, 56%) than in asymptomatic women (2/12, 17%) (P = 0.035). Four patients developed non-Hodgkin's lymphoma during the follow-up. Eighteen patients died. Vascular events and hematological malignancies represented the most frequent causes of death (n = 5 for each).The present study shows that: (a) previous thrombosis and ACA titer40 U are independent predictors of thrombosis; (b) history of miscarriage or vascular disease is significantly associated with adverse pregnancy outcome; (c) hematological malignancies can develop during follow-up in patients with antiphospholipid antibodies.

Eight healthy volunteers (6 males, 2 females, mean age 31,6 yrs), were administered-on three separate days − 200, 400 and 800 mg of a new low molecular weight Dermatan sulphate (Desmin), given as a single i.v. bolus (2 min.) injection. Before each administration and 10, 20, 30 min., 1, 2, 4, 8, 12, 24 hours after, blood samples were drawn and the following coagulative assays performed: aPTT (activated Partial Thromboplastin Time), TT (Thrombin Time), anti Xa (Xa Factor inhibition), Heptest, Stachrom D.D., Furthermore, a kinetic analysis was performed on the activity curves calculated on the Heptest and Stachrom data. Plasma peak values and half lives of the parameters checked showed a clear dose-effect relationship. aPTT and TT showed very short-lasting variations and the inhibition of Factor Xa was moderate, but significant. The most evident and specific effects of Desmin were those on Heptest and Stachrom D.S.: both tests were influenced in a clear-cut and dose-dependent way, mainly as a consequence of the action of Desmin on HCII, with partially different kinetic patterns. A series of in vitro experiments proved an anti Xa effect of Desmin, mediated by antithrombin III, well above the possible interference of the small (< 1%) heparin contaminants in Desmin. An even more marked anti Xa activity was seen in the in vivo study, an observation so far unrecognized for this type of drug: some possible interpretations of this fact are discussed.

We report a new case of severe bleeding diathesis due to an acquired inhibitor of fibrin crosslinking. The patient, an 80-year-old woman, was admitted to the hospital for a massive subcutaneous hematoma, with severe anemia requiring red cell transfusion; a subsequent retroperitoneal hematoma developed 2 weeks later. Coagulation studies were normal except for a thromboelastographic pattern suggestive of FXIII deficiency. Clot solubility test was abnormal even after 1: 1 mix with normal plasma. Immunochemical studies confirmed the presence of a monoclonal IgG lambda inhibitor directed against FXIII activity (type II FXIII inhibitor). The patient IgG fraction selectively inhibited FXIII transamidating activity but did not inhibit the thrombin-mediated activation of FXIII. The patient was treated with high doses of FXIII concentrate to overcome the inhibitor and immunosuppressive therapy with cyclophosphamide and discharged in good conditions. High doses of commercially available FXIII appear to be a safe and effective method of controlling acute episodes of bleeding in patients with acquired FXIII deficiency. ©1995 Wiley-Liss, Inc.

The results of a cooperative study on the quality of treatment of patients with prosthetic heart valves (PHV) on long-term oral anticoagulants (OA) are reported. The study was carried out on 695 patients bearing PHV (with an overall 8,340 checks carried out in 1988) through a computer-assisted system for monitoring the laboratory and treatment follow-up. The specifications of the software are described in detail in the text. The mean INR slightly differed in the two participating centers (Rome and Parma) (3.25 vs 3.19) as did the weekly mean dosage (18.2 vs 20.7 mg) of oral anticoagulant, which was always Acenocoumarol. More than 70% of the checks were within the range in both centers as evaluated by a check randomly chosen once a month for each single patient. Considering the whole bunch of data, about 80% of the patients had greater than 50% of their checks within the therapeutic range and more than 30% had greater than 75% of the checks within the range. This study demonstrates that the availability of a computerized program for monitoring oral anticoagulant therapy allows to perform multicenter studies and to obtain data which can improve the quality of treatment of patients on OA.

Bagnall and collegues[1][1] report a technique to investigate an inversion that disrupts the factor VIII ( F8 ) gene and that represents a frequent cause of severe hemophilia A. This large genomic rearrangement, identified for the first time by Brinke et al[2][2] in 2 haemophilic monozygotic twins

A young woman was admitted to our Department for a sudden occlusion of the proximal deep venous stream of the right lower limb, and a controlateral recurrence within a few days, during the tenth week of pregnancy. Diagnosis was made by strain-gauge pletismography. We found she had a type 1 congenital AT III defect (AT III activity : 35%; AT III antigenic level : 40%), never diagnosed before

A significant decrease of plasma antithrombin III (AT III) levels, measured with four different biological and immunological methods, was found in 8 of 11 members of a Sicilian family (family DM) and in 3 of 14 members of a northern Italian family (family A). Different behaviour after oral anticoagulant treatment with acenocoumarin was seen in 2 long-term treated subjects. The propositus of family DM, who had had a long history of recurrent thrombosis, did not show any increase of AT III levels. A significant increase was, on the contrary, observed in the propositus of family A, who had suffered a recent thrombosis in a branch of the inferior mesenteric vein.

2 cases of acute idiopathic thrombotic thrombocytopenic purpura are reported. Both of them were treated with plasma exchange, antiplatelet drugs and prednisolone and both completely recovered. Plasma exchange appeared to be the critical treatment. In 1 of these cases the prostacyclinlike activity released from venous tissues and the ability of plasma to stimulate synthesis of prostacyclinlike activity from venous tissues exhausted after repeated washings were investigated. Both activities were detectable and comparable to those of a healthy control. These findings do not support the hypothesis of a major role played by the prostacyclin system in the pathogenesis of thrombotic thrombocytopenic purpura.

Two automatic coagulometers--ACL 810 (Instrumentation Laboratory), a laser-nephelometric centrifugal analyzer, and KoaguLab 40 A (Ortho Diagnostics), an optical automatic coagulometer--were compared with the manual tilt-tube method for the performance of prothrombin time (PT). Seven ISI- (International Sensitivity Index) calibrated commercial thromboplastin reagents were used for duplicate determinations in 30 normal subjects, 30 patients with liver disease, and 30 patients receiving stabilized oral anticoagulation. Clotting times were longer with the manual method than with ACL 810 and, to a lesser extent, with KoaguLab 40 A. Average imprecision of duplicate determinations (CV) was less than 1% with ACL 810; KoaguLab 40 A and the manual method had similarly higher imprecisions (2.8% and 2.7%). Differences in origin and slope of the regression curves of clotting times obtained with the coagulometers over the tilt-tube method were observed with all the reagents tested. Transformation of clotting times to PT ratios did not eliminate the bias resulting from the different clot-detection methods. A higher percentage of patients with liver disease had abnormal PT ratios when their plasma was tested with the coagulometers than with the manual method. Transformation of PT ratios to International Normalized Ratios effectively eliminated the bias resulting from the different thromboplastin reagents but had no effect on the bias resulting from the different clot-detection methods. A significant proportion of patients appeared excessively anticoagulated (INR greater than 4.5) with the coagulometers but not with the manual method. These results highlight the need for standardization of both instrumentations and reagents to improve monitoring of oral anticoagulant treatment.

A new factor X (FX) assay based on the chromogenic substrate S-2337 was compared with the coagulation screening method Thrombotest (TT) in 1431 plasma samples from 188 patients followed up for 6–8 months on long-term oral anticoagulants. In all the participating laboratories, the results of the methods were highly correlated (P

Factor VIII coagulant activity (FVIII:C) and fibrinolytic activity (FA) were measured in a group of patients with peripheral arterial disease (PAD) and in a comparable control group. The effects of two stimuli, venous occlusion (VO) and nicotinic acid administration (NA), were also investigated. Significant or highly significant increases of both activities were found after VO and after NA in both groups. A linear correlation was seen between basal and post-stimulus values for FVIII:C, while only a logarithmic relation was present for FA in the same conditions. No correlation was observed between the two activities, either before or after stimuli. The response of FVIII:C to VO was correlated with that to NA, while no similar correlation was evident for FA. No significant difference was recorded between patient and control group, both for FVIII:C and for FA, before and after the considered stimuli.

The authors evaluated whole blood filterability (VB) in 29 post-menopausal obese women with (n = 14) or without (n = 15) hypertension, and in 22 age matched women with normal body weight. After 3 months of a low-calorie (18 kcal/kg IBW) and moderately low-salt (max 6 g NaCl/day) diet, the obese subjects were restudied. In all women plasma fibrinogen values and various indices of metabolic status were evaluated before and after the diet and correlated to VB values. VB values and plasma fibrinogen concentrations were similar in normal controls and in women with simple obesity, whereas they were, respectively, significantly lower and higher in obese subjects with hypertension. Three months of diet significantly improved whole blood filterability and decreased fibrinogen levels in these patients. Before the diet a significant negative correlation was found between VB and plasma fibrinogen values in hypertensive obese patients. Metabolic parameters did not change in the different groups before and after the diet and did not correlate with VB values. The present study indicates that low-calorie, low-salt diet decreases plasma fibrinogen levels and improves whole blood filterability in elderly obese women with hypertension.

Isolated deficiencies of protein C and protein S, two vitamin K-dependent plasma proteins, constitute about 70% of the congenital abnormalities of blood coagulation observed in patients with recurrent venous thrombosis beLow the age of 40. The laboratory diagnosis of congenital deficiency of these proteins represents a major problem since a large proportion of patients are on oral anticoagulation (OA) at the time the deficiencies are suspected.Under these circumstances the availability of a reference interval obtained in patients on stabilized OA has proven useful.Functional (C) and antigenic levels (Ag) of protein C, protein S, factor IX and II were estimated in 136 patients on stabilized OA, subdivided according to the degree of anticoagulation (Internatio nal Normalized Ratio, INR).The results indicate that with increasing anticoagulation the activity levels of all the vitamin K-dependent factors decrease to a greater extent than the corresponding antigenic levels. At variance with the other factors, total protein S antigen levels are only moderately reduced by OA with protein S anticoagulant activi ty comparing well to factor IX clotting activity. These data suggest the possibility of identifying both quantitative and qualita tive deficiencies of protein C and protein S in patients on oral anticoagulant treatment.

The prothrombin time (PT) is the most widely used assay to monitor oral anticoagulation (OA). Although it has been established that both thromboplastin and instrumentation significantly affect the results, major standardization attempts have been devoted to the calibration of reagents rather than of instruments. To provide safe laboratory monitoring of OA, an International Sen sitivity Index (ISI) for thromboplastin has been introduced. We have compared two automatic coagulometers, the ACL (Instrumentation Laboratory), a laser-nephelometer centrifugal analyzer which measures the intensity of the light scattered by a plasma sample before, during and after clot formation and the KOAGULAB 40A (Ortho Diagnostics), an optical automatic coagulometer, with the till tube technique for the performance ofPT. Five calibrated commercial thromboplastins have been used for replicate determinations in 30 normals, 30 liver disease patients and 30 patients on stabilized OA. The overall observed imprecision (C.V.) was 1.1% for ACL, 2.9% for the KOAGULAB 40A and 3.0% for the till tube technique. The F test for the two-way interaction of ratios was statistically significant (p< O.OOl) for the large majority of reagent/technique combinations in normals and in liver disease patients. Internatio nal normalized ratios were also significantly different (p< O.OOl) in most instances in patients on OA. Inadequate anticoagulation (INR 4.5) was observed in 19% of the patients with the ACL, in 7% with KOAGULAB 40A and in 3% with the till tube tech nique. These data highlight the need for standardization of both instrumentations and reagents to improve monitoring of OA.

SummaryIn 107 asymptomatic and untreated patients with inherited syndromes associated with thrombophilia (antithrombin III, protein C and protein S deficiencies), we compared in parallel two plasma peptides which reflect activation of the common coagulation pathway: the prothrombin fragment 1 + 2 (F1+2) and fibrinopeptide A (FPA). Both F1+2 and FPA were measured with simple, commercially available ELISA methods. High levels of F1+2 or FPA were found in about one fourth of the patients as a whole. When patients were divided according to the type of inherited thrombophilie syndrome, it appeared that F1+2 was more frequently elevated in protein C and protein S deficiencies than in antithrombin deficiency; and that, in general, it was no more frequently elevated than FPA. Although our data confirm the existence of a procoagulant imbalance in inherited thrombophilie syndromes due to defects of natural anticoagulant proteins, they do not confirm that such imbalance can be more frequently diagnosed by measuring F1+2 levels, particularly in patients with antithrombin deficiency.

SummaryThe paper reports on rate and type of thrombotic events occurring during the observational, prospective, inception-cohort, multicenter ISCOAT study. 2,745 unselected, daily practice patients, consecutively referring to 34 Italian anticoagulation clinics to monitor the oral anticoagulant treatment, were included in the study from beginning of their first anticoagulant course. During a total follow-up of 2,011 patient-years of treatment 70 thrombotic events (3.5 per 100 patient years) were recorded in 67 patients: 20 fatal (1%), 39 major (1.9%) and 11 minor (0.6%). 34/70 events occurred within the first 90 days of treatment (relative risk - at multivariate analysis - of 90 = 20.6, C.I. 12.7-33.5; p 70 y (1.62, C.I. 1.0-2.61; p 2 = 1.88, C.1.1.16-3.07; p The recorded rate of thrombotic events was lower than that reported in the few available studies. A greater risk should be expected during the first 90 days of treatment, when anticoagulation levels are 70 years and in those with cerebrovascular/peripheral arterial disease.

SummaryThe International Sensitivity Index (ISI) of thromboplastins is determined by calibration using fresh plasmas from 60 patients stabilized on oral anticoagulants and 20 healthy subjects. This procedure is demanding, particularly for those who have no easy access to patients. The alternative use of a smaller number of lyophilized plasmas has already been considered, but one important issue, the number of repeated measurements to be carried out, has never been addressed. Two commercial rabbit thromboplastins, A and B, were calibrated in 3 laboratories against CRM 149R. On each of 10 working days, prothrombin times were measured for a different set of 8 fresh plasmas and for the same set of 8 lyophilized plasmas. The ISI values for both thromboplastins were estimated by orthogonal regression on fresh and lyophilized plasmas. The between- and within-laboratory CV values of the estimated ISI were taken as measures of precision of the calibration. In addition, ISI and CV were calculated daily on cumulative results obtained with lyophilized plasmas from day 1 to day 10. The ISI values for both thromboplastins calculated with lyophilized plasmas were not significantly different from those with fresh plasmas (mean of 3 laboratories: 1.42 vs 1.48 for A and 1.22 vs 1.20 for B). The between-laboratory precision of the calibration with lyophilized plasmas was not considerably different from that with fresh plasmas (CV for 3 labs: 5.2% vs 6.8% for A and 0.9% vs 2.2% for B). The ISI estimated with lyophilized plasmas on results of day 1 were not different from those of days 2 through 10. Good within-laboratory precision of the calibration (CV around 2%) was already achieved on day 3. In conclusion, this study shows that lyophilized plasmas pooled from normals and patients on oral anticoagulants can be used as substitutes for individual fresh plasmas to simplify the existing procedure for thromboplastin calibration.

SummaryThe optimal long-term treatment of acute venous thromboembolism (VTE) in patients with malignancy remains undefined. In particular, based on current evidence, it is uncertain whether secondary prophylaxis using standard intensity oral anticoagulant therapy is associated with higher risks of bleeding and recurrent thrombosis in patients with cancer than in those without cancer. This study compared the outcome of anticoagulation courses in 95 patients with malignancy with those of 733 patients without malignancy. All patients were participants in a large, nation-wide population study and were prospectively followed from the initiation of their oral anticoagulant therapy.Based on 744 patient-years of treatment and follow-up, the rates of major (5.4% vs 0.9%), minor (16.2% vs 3.6%) and total (21.6% vs 4.5%) bleeding were statistically significantly higher in cancer patients compared with patients without cancer. Bleeding was also a more frequent cause of early anticoagulation withdrawal in patients with malignancy (4.2% vs. 0.7%; p In conclusion, patients with malignancy treated with oral anticoagulants have a higher rate of bleeding and possibly an increased risk of recurrent thrombosis compared with patients without malignancy. Safer and more effective anticoagulant therapy is needed for this challenging group of patients.

Whether elderly patients are at increased risk of complications during oral anticoagulant treatment (OAT) is still a matter of debate.Bleeding and thrombotic events occurring during OAT in 461 patients, aged 75 years or older when they started OAT, and in 461 patients younger than 70 years, matched for sex, OAT indication, and treating center, were examined in a prospective, multicenter, inception-cohort study.Bleeding rate was 9.9% and 6.6% patient-years in elderly and young patients, respectively (P = .07), and 2.1% and 1.1% for major bleeding (P = .19); 6 and 1 events, respectively, were fatal (all intracranial, relative risk, 6.4; P = .05). In the elderly, bleeding rate was lower (4.5%) for international normalized ratios (INRs) between 2.0 and 2.9; it was higher during the first 90 treatment days (P = .05) and when arterial vascular disease was the indication for OAT (P = .03). Thrombosis rate was 4.2% and 2.5% patient-years in elderly and young patients, respectively (P = .10); however, 13 and 5 events were fatal (relative risk, 2.8; P = .04). Thrombosis rate was lower (1.5%) for INRs between 2.0 and 2.9; it was higher during the first 90 treatment days (P.001) and 6 of 7 venous events occurred at lower than 2.0 INRs.A nonsignificant trend was noted toward a higher rate of both bleeding and thrombotic complications in elderly vs matched younger patients. Intracranial bleeding and fatal thrombotic events were significantly more frequent in the elderly. Our results also indicate that lower than 2.0 INRs do not preclude bleeding in the elderly nor offer adequate protection from thrombotic events. Moderate anticoagulation (2.0-3.0 INRs) in elderly patients seems the safest and most effective.