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An increasing observation is that some patients with COVID-19 have normal lung compliance but significant hypoxaemia different from typical acute respiratory distress syndrome (ARDS). We hypothesised that changes in pulmonary blood distribution may be partially responsible and used functional respiratory imaging on CT scans to calculate pulmonary blood volume. We found that patients with COVID-19 had significantly reduced blood volume in the smaller calibre blood vessels (here defined as <5 mm2 cross-sectional area) compared with matched ARDS patients and healthy controls. This suggests that using high levels of PEEP may not alone be enough to oxygenate these patients and that additional management strategies may be needed. [ABSTRACT FROM AUTHOR]

Rationale: Severe pulmonary hypertension (PH) is very uncommon in COPD, and a distinct phenotype has been hypothesised. We aimed to evaluate whether CT can help to recognise this condition non-invasively by measuring small pulmonary vessels.Material and Methods: Patients with COPD who underwent pulmonary function tests, unenhanced CT of the chest and right heart catheterisation (RHC) during a period of stability were included in the study. From 105 included patients, 20 patients with COPD with severe PH (mean pulmonary arterial pressure, mPAP>35 mm Hg) were compared with 20 FEV1-matched and age-matched patients with COPD with mild or without PH (mPAP<35 mm Hg). The percentage of total cross-sectional area of vessels less than 5 mm(2) normalised by lung area (%CSA<5) and 5-10 mm(2) (%CSA5-10), the mean number of cross-sectioned vessels (CSNs) and bronchial wall thickness (WT) were measured on CT examination and compared between groups. Paw scores combining PaO2 measurement and CT parameters best correlated with mPAP were compared by receiver operating characteristic analysis to predict severe PH in COPD.Results: Patients with severe PH COPD had higher %CSA and CSN values than those of patients with COPD without severe PH. Using multiple regression analysis, %CSA<5 and WT were the best predictors of mPAP in patients with and without severe PH, respectively. A score combining %CSA<5, PaO2 and WT best predicted severe PH in patients with COPD.Conclusions: CT measurements of small vessels support a distinct vessel-related phenotype in patients with COPD with severe PH, and combined with WT and PaO2 parameters in the paw score, which may offer a non-invasive tool to select patients for RHC. [ABSTRACT FROM AUTHOR]

Objective At birth, an initial sustained inflation (SI) uniformly aerates the lungs, increases arterial oxygenation and rapidly improves circulatory recovery in asphyxiated newborns. We hypothesised that lung aeration, in the absence of an increase in arterial oxygenation, can increase heart rate (HR) in asphyxiated near-term lambs. Interventions Lambs were delivered and instrumented at 139±2 days of gestation. Asphyxia was induced by umbilical cord clamping and then delaying the onset of ventilation until mean carotid arterial pressures (CAPs) had decreased <20 mm Hg. Lambs then received a single 30-s SI using nitrogen (N2; n=6), 5% oxygen (O2; n=6), 21% O2 (n=6) or 100% O2 (n=6) followed by ventilation in air for 30 min. Main outcome measures HR, CAP and pulmonary blood flow (PBF) were continuously recorded. Results HR and PBF increased more quickly in lambs resuscitated with 100% and 21% O2 than with 5% O2 or N2. HR and PBF recovery in the 5% O2 group was delayed relative to all other oxygen SI groups. HR in 5%, 21% and 100% O2 groups reached 100 bpm before the SI was complete. HR and PBF in the N2 group did not increase until 10 s after the SI was completed and ventilation was initiated with air. CAP tended to increase quicker in all O2 groups than in N2 group. Conclusions Oxygen content during an SI is important for circulatory recovery in asphyxiated lambs. This increase in HR is likely driven by the increase in PBF and venous return to the heart. [ABSTRACT FROM AUTHOR]

Background Pulmonary arterial hypertension (PAH) is a commonly fatal pulmonary vascular disease that is often diagnosed late and is characterised by a progressive rise in pulmonary vascular resistance resulting from typical vascular remodelling. Recent data suggest that vascular damage plays an important role in the development of radiation-induced pulmonary toxicity. Therefore, the authors investigated whether irradiation of the lung also induces pulmonary hypertension. Methods Different sub-volumes of the rat lung were irradiated with protons known to induce different levels of pulmonary vascular damage. Results Early loss of endothelial cells and vascular oedema were observed in the irradiation field and in shielded parts of the lung, even before the onset of clinical symptoms. 8 weeks after irradiation, irradiated volume-dependent vascular remodelling was observed, correlating perfectly with pulmonary artery pressure, right ventricle hypertrophy and pulmonary dysfunction. Conclusions The findings indicate that partial lung irradiation induces pulmonary vascular remodelling resulting from acute pulmonary endothelial cell loss and consequential pulmonary hypertension. Moreover, the close resemblance of the observed vascular remodelling with vascular lesions in PAH makes partial lung irradiation a promising new model for studying PAH. INSET: Key messages. [ABSTRACT FROM AUTHOR]

Background The bidirectional cavopulmonary connection {BCPC) is used in the staged palliation of univentricular hearts and places the cerebral and pulmonary vascular beds in series. Angiotensin-converting enzyme inhibitors {ACEI) are often used in this complex circulation, but the effects of their vasodilation are unclear. Objective Assessment of the acute response of perfusion pressure, flow and resistance across the systemic, cerebral and pulmonary vascular beds to ACEI in patients with a BCPC. Design Prospective interventional study. Setting Single tertiary care centre. Patients 12 patients with a BCPC (median age 28 months, weight 11.8 kg) undergoing a pre-Fontan catheterisation with MRI measurement of flows. Intervention Intravenous enalaprilat 0.005 or 0.01 mg/kg. Results Enalaprilat increased descending aorta flow {median 21.6%, p=0.0005), decreased total pulmonary vein flow {median 10.6%, p=0.025), and both superior caval vein flow {median 8.6%, p=0.065) and aortopulmonary collateral flow {median 15.5%, p=0.077) tended to decrease. Total cardiac output was unchanged {p=0.57). Systemic vascular resistance (median 41.9%, p=0.0005) and cerebral vascular resistance {median 23.4%, p=0.0005) decreased, but pulmonary vascular resistance {p=0.73) showed little change. There was evidence of autoregulation of cerebral blood flow. The proportion of descending aortic flow to total cardiac output increased {median 27 to 35%, p=0.001). Systemic oxygen saturation decreased from 87% to 83% (p=0.02). Conclusion Enalaprilat did not increase total cardiac output but redistributed flow to the lower body, with a concomitant decrease in arterial oxygen saturation. It is difficult to increase cardiac output in patients with a BCPC and ACEI should be used with caution in those with borderline aortic saturations. [ABSTRACT FROM AUTHOR]

Objectives To develop a non-invasive method of assessing disease severity in pulmonary hypertension by quantifying the overall degree of vascular pruning using fractal geometry. Design A retrospective analysis of ECG-gated CT pulmonary angiograms. Setting A single national referral centre for the investigation and treatment of children with pulmonary hypertension. Patients Consecutive CT pulmonary angiograms in children and young adults (mean age 10.3 years, range 0.7e19.1) with pulmonary arterial hypertension assessed between January 2007 and April 2009. Main outcome measures The fractal dimension (FD) of skeletonised CT pulmonary angiograms was calculated using the box counting method. The FD was compared with pulmonary vascular resistance, the percentage of predicted 6-min walk distance, WHO functional class and survival. Results Diagnostic plots confirmed that the pulmonary artery angiograms were all fractal. The FD correlated negatively with the pulmonary vascular resistance index (r=-0.55, p=0.01, n=21) and with WHO functional class (p<0.01, n=31) while it correlated positively with the percentage of predicted 6-min walk distance (r=0.43, p=0.04, n=24). A lower FD was associated with poorer survival (HR 5.6; 95% CI 1.2 to 25; p=0.027) for every SD reduction in FD. Conclusion The FD derived from CT can be used to quantify vascular changes in pulmonary hypertension. This non-invasive technique may be useful in monitoring disease progression and response to therapy. [ABSTRACT FROM AUTHOR]

After birth, gas exchange is achieved in the lung, whereas prenatally it occurs in the placenta. This is associated with differences in blood flow patterns in the fetus as compared with the postnatal circulation. Congenital cardiovascular malformations are associated with haemodynamic changes in the fetus, which differ from those occurring postnatally. Obstruction to cardiac outflow may alter myocardial development, resulting in progressive ventricular hypoplasia. Alteration of oxygen content may profoundly influence pulmonary vascular and ductus arteriosus responses. Interference in blood flow and oxygen content may affect cerebral development as a result of inadequate oxygen or energy substrate supply. The circulatory effects may be gestational dependent, related to maturation of vascular responses in different organs. These prenatal influences of congenital cardiac defects may severely affect immediate, as well as long- term, postnatal prognosis and survival. This has stimulated the development of techniques for palliation of disturbed circulation during fetal life. [ABSTRACT FROM AUTHOR]

The article reports on the challenges encountered in the measurement of right ventricle (RV) volume and function in the context of RV's different anatomic structure and physiology. Right ventricle's physiology depends on the low hydraulic impedance characteristics of the pulmonary vascular bed. Its challenges are the recognition of RV dysfunction in the pathogenesis of many cardiovascular diseases using 3D imaging and the opportunity for therapeutic interventions in biventricular circulation.

Objective: Pulmonary venous Doppler (PVD) patterns are abnormal in fetuses with hypoplastic left heart syndrome )HLHS) with restricted foramen ovale (rFO) when compared with healthy fetuses. The objective of this study was to define PVD patterns in HLHS fetuses with an unrestricted or patent foramen ovale (pFO). Design: 27 fetuses with HLHS and 66 healthy fetuses underwent echocardiography between 19 and 38 weeks of gestation. The pulmonary venous peak systolic (SI, diastolic (0) and atrial reversal IA) velocities were measured; S/D ratio, velocity time integral of forward (VTlf) and reversed (VTlr) flows and VTIr expressed as percentage of VTIf (%R( were calculated. Independent examiners classified HLHS subjects into HLHS-pFO and HLHS-rF0 (rEQ or intact atrial septum). Setting: Tertiary referral centre for paediatric cardiology. Results: Compared with healthy controls, the HLHS-pFO group (n = 161 had higher S (32.9 (3.2) vs 23.5 (1.6) cm/s (adjusted mean (SE)); p = 0.01), A (10.5 (3.4) vs 0.17 (1.6) cnVs; p = 0.01), VTIr (0.78 (0.3) vs 0.01 (0.13) cm; p = 0.01) and %R (14.2% (3.2 %) vs -1.3% (1.5%); p<0.001). 0 velocity, S/D and VTIf showed no difference. In HLHS-rFO, further increase in S, A, VTIr and %R, decrease in 0, increase in S/D and no change in VTIf were noted. Conclusions: PVD flow patterns are abnormal in HLHS even in the absence of rFO, suggesting that factors other than impaired left atrial egress play a role. Future studies of PVD patterns can provide important insights into left atrial dynamics, pulmonary venous return and pulmonary vascular development in fetal HLHS. [ABSTRACT FROM AUTHOR]

Pulmonary hypertension is relatively common in children and has many causes. The management of the condition has changed dramatically in the past 5 years with the introduction of new medicines. However, diagnosis, investigation and choice of therapy remain a challenge. In 2002 the United Kingdom Pulmonary Hypertension Service for Children was established and this has become the mainstay of management in this country. This service, based at Great Ormond Street Hospital for Children, provides advice, expertise and infrastructure support for the most severely affected patients, particularly those with idiopathic pulmonary arterial hypertension for whom chronic intravenous prostacyclin remains the most effective medication. New medicines are being developed which, rather than focussing on dilating a diseased pulmonary vascular bed, aim to structurally remodel the pulmonary vasculature towards normal. [ABSTRACT FROM AUTHOR]

Background: Atrial fibrillation is commonly associated with dilated pulmonary veins. Stretch has been shown to have mechano-electrical effects. Objective: To investigate whether stretch can increase the arrhythmogenic activity of the pulmonary veins. Methods: The transmembrane action potentials were recorded from rabbit pulmonary veins before and after stretch (100 and 300 mg). Gadolinium and streptomycin (stretch-activated ion channel blockers) were each perfused into the pulmonary veins under a 300-mg stretch. Results: Stretch (0, 100 and 300 mg) force dependently increased the incidence of spontaneous activity (22%, 48% and 83%; p<0.05), mean (standard deviation (SD)) firing rates of spontaneous activity (1.7(0.2), 2.1(0.3) and 3 (0.2) Hz; p<0.05) and incidence of early post-depolarisations (9%, 26% and 61%; p<0.05) and delayed post-depolarisations (0%, 4% and 30%; p<0.05) in 23 pulmonary veins. In the seven preparations with spontaneous activity after the 300-mg stretch, gadolinium (1, 3 and 10 µmol/l) decreased the incidence of spontaneous activity by 43%, 29% and 14%, respectively (p<0.05), and decreased the firing rate from 2.9 (0.1) Hz to 0.8 (0.4), 0.3 (0.1) and 0.1(0.1) Hz, respectively (p<0.05). Streptomycin (10 and 40 µmol/l) decreased the incidence of spontaneous activity by 71% and 29%, respectively (p<0.05), and decreased the firing rate from 2.9 (0.1) Hz to 1.6 (0.4) and 0.5 (0.3) Hz, respectively (p<0.05). Conclusion: Stretch is an important factor in the electrical activity of the pulmonary vein. Stretch-induced arrhythmogenic activity of the pulmonary vein may contribute to the genesis of atrial fibrillation. [ABSTRACT FROM AUTHOR]

Background and aims: Increased endothelin (ET)-1 activity may contribute to the complications of cirrhosis and portal hypertension. The aim of this study was to assess the systemic and portal haemodynamic effects of selective ET-A and ET-B receptor antagonism in patients with cirrhosis. Methods: Sixteen patients with cirrhosis and portal hypertension (aged 52 (1) years, Pugh score 6.2 (0.3)) underwent 24 studies with infusions of: (A) selective ET-A antagonist, BQ- 123 (n = 8), at 1000 and 3000 nmol/min; (B) selective ET-B antagonist, BQ-788 (n = 8), at 100 and 300 nmol/min; or (C) matched saline placebo (n = 8) in a double blind randomised manner. Haemodynamic measurements were performed through pulmonary artery, hepatic venous, and femoral artery catheters. Results: Baseline patient characteristics were well matched. Compared with placebo, BQ-123 decreased mean arterial pressure (MAP -15 (11) mm Hg (-18%); p<0.02) and pulmonary vascular resistance index (PVRI -81 (54) dyn×s×m²/cm5 (-64%); p<0.05), with no effect on hepatic venous pressure gradient (HVPG), cardiac index (Cl), or systemic vascular resistance index (SVRI). Compared with placebo, BQ-788 increased MAP (+11 (3) mm Hg (+12%); p<0.03) and SVRI (+1101 (709) dyn×s×m²/ cm5 (+50%); p<0.05), reduced Cl (-1.0 (0.4) l/min/m² (-29%); p = 0.05) with no effect on HVPG or PVRI. Conclusions: ET-1 contributes to maintenance of systemic and pulmonary haemodynamics without acutely affecting HVPG in patients with early cirrhosis. In this group of patients, the use of selective ET-A and ET-B antagonists for the management of variceal haemorrhage is likely to be limited. [ABSTRACT FROM AUTHOR]

Objectives: To measure survival, haemodynamic function and functional class in patients with systemic sclerosis associated pulmonary arterial hypertension (SSc-PAH) in two treatment eras. Methods: Six year longitudinal study of 92 consecutive patients with SSc-PAH diagnosed by cardiac catheterisation. Data were collected both prospectively and retrospectively. Patients were given basic treatment (diuretics, digoxin, oxygen and warfarin). Where clinically indicated, a prostanoid was used as advanced treatment (historical control group). From 2002, the range of treatments available expanded to include bosentan, which was generally the preferred treatment (current treatment era group). Survival was measured from the date of diagnosis of pulmonary hypertension by cardiac catheterisation. Six minute walking distance and haemodynamic function were measured at the time of diagnosis and at least one month after treatment was started. Results: The historical control group comprised 47 patients, all of whom received basic treatment; 27 of these were also treated with prostanoids. The current treatment era group comprised 45 patients, all of whom received bosentan as preferred treatment. Kaplan-Meier survival in the historical control group was 68% at one year and 47% at two years. Survival in the current treatment era group was 81% and 71% (p = 0.016) at one and two years, respectively. Pulmonary vascular resistance increased in the historical control group (by 147 dyn·s·cm-5), whereas in the current treatment era group, it remained stable over an average of nine months (decrease of 16 dyn·s·cm-5, p < 0.006). Conclusion: Survival of selected patients with SSc-PAH has improved in the current treatment era. In contrast to patients treated historically with basic drugs and prostanoids, patients treated in the current treatment era had improved survival associated with a lack of deterioration in cardiac haemodynamic function. [ABSTRACT FROM AUTHOR]

Objectives: To test whether magnetic resonance (MR) imaging can be used to assess differential lung blood flow as accurately as isotope lung perfusion studies in patients investigated for congenital heart disease. Methods and results: Radionuclide lung perfusion and MR imaging were performed in 12 children with suspected unilateral branch pulmonary artery stenosis (mean age 12.1 (5.9) years, range 3.1–17.2 years). A non-breath hold, fast gradient echo phase contrast MR sequence was used to measure flow in the pulmonary trunk and one pulmonary artery to calculate differential flow. Good agreement was shown between the two imaging methods by Bland-Altman analysis. There was excellent correlation between the radionuclide and MR phase contrast calculated total lung blood flow (r = 0.98, p < 0.0001). Conclusion: MR phase contrast is an accurate method for measuring differential total right and left lung blood flow. If MR imaging is performed to assess the branch pulmonary arteries, differential lung blood flow can be also measured, avoiding the need for an additional radionuclide lung perfusion scan and reducing the overall radiation burden to this group of patients. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the growth of the pulmonary arteries after a Fontan procedure. Design: Retrospective review. Selling: Two paediatric cardiology tertiary care centres. Patients: 61 children who underwent a modified Fontan operation and had angiography suitable for assessment of pulmonary artery size before the Fontan procedure and during long term follow up. An atriopulmonary connection (APC) was present in 23 patients (37.7%) and a total cavopulmonary connection (TCPC) was present in 38 (62.3%). Postoperative angiograms were performed 0.5–121 months (median 19 months) after the Fontan operation. Main outcome measure: Growth of each pulmonary artery measured just before the first branching point. The diameter was expressed as a z score with established nomograms used to standardise for body surface area. Results: The mean change in the preoperative to postoperative z scores of the right pulmonary artery was -1.06 (p = 0.004). The mean change in the preoperative to postoperative z scores of the left pulmonary artery was -0.88 (p = 0.003). Changes in the preoperative to postoperative z scores were more pronounced in the patients undergoing APC than TCPC, especially for the right pulmonary artery. Conclusion: After the Fontan operation, growth of the pulmonary arteries often fails to match the increase in body surface area. [ABSTRACT FROM AUTHOR]

Objective: To investigate the feasibility of catheter ablation as a treatment for symptomatic patients with longstanding permanent atrial fibrillation (AF). Methods: Radiofrequency ablation was applied to encircle all pulmonary veins (PVs) and create lines from the left inferior PV to the mitral valve, along the roof of the left atrium between the PVs, and along the tricuspid valve-inferior vena cava isthmus. A seven day Holter was recorded at discharge and at follow up to assess arrhythmia burden. If patients developed a symptomatic, sustained atrial arrhythmia a repeat ablation procedure was advised. Results: 42 patients underwent the procedure that took a mean of five hours with 50 minutes of fluoroscopy. After a median follow up of 8.4 months, 31 of 41 surviving patients (76%) were in sinus rhythm. Of these, 29 patients were no longer taking any antiarrhythmic drugs but 22 (52%) required more than one procedure. During follow up 49% experienced a sustained atrial tachycardia. Twenty six repeat procedures were performed. Maintenance of sinus rhythm after the first, second, or third procedure was 36% (15 of 42), 58% (11 of 19), and 71% (5 of 7), respectively. From a total of 68 procedures there were two serious complications (2.9%): a stroke from which a full recovery was made, and a PV stenosis. Conclusion: Catheter ablation can be used to cure longstanding permanent AF; however, there is a significant complication rate. Whether this is offset by a mortality benefit associated with sinus rhythm is unknown. Many patients will need more than one procedure to achieve success. [ABSTRACT FROM AUTHOR]

Objective: To review the outcome of cardiac transplantation for restrictive cardiomyopathy (RCM) in children and to assess the ability of new strategies to modulate the effects of high pulmonary vascular resistance. Design: Retrospective case note analysis of all patients receiving a transplant for RCM. Patients: 18 children with RCM referred for transplantation assessment to Great Ormond Street Hospital, London. Results: Eight boys and 10 girls were referred for assessment. Median age at presentation was 5.0 (mean (SD) 6.1 (4.0)) years. Fourteen orthotopic and two heterotopic transplantations were performed and two patients were referred for heart-lung transplantation. Mean duration from diagnosis to transplantation was 3.3 (3.0) years. Three patients with haemodynamic decompensation before transplantation had increased morbidity in the postoperative period. No patients died while awaiting a transplant. Three patients died in the first year after transplantation, one within 30 days. Five patients received pre-transplantation prostacyclin for a mean duration of 57 (18) days. Transpulmonary gradient was reduced in four of the patients. Mean transpulmonary gradient was 27 (9.8) mm Hg before and 17 (6.7) mm Hg after treatment with prostacyclin (p < 0.05). Conclusion: Most children with RCM require transplantation within four years of diagnosis. Referral for transplantation assessment should precede haemodynamic decompensation. Increase of pulmonary vascular resistance is a variable problem but can be modulated with pre-transplantation prostacyclin. With these strategies, orthotopic transplantation is possible in the majority of cases. [ABSTRACT FROM AUTHOR]

The article presents abstracts on pulmonary vascular diseases. They include "Haemolytic Disorders Complicated by Pulmonary Hypertension," by C.A. Elliot, J. Wright, K. Ryan, M. Woodhead, I.J. Armstrong, T.S. Saba and D.G. Kiely, "Histology of Arteriolar Wall Remodelling in a Lung Volume Reduction Surgery Patient Cohort," by G. Sirico, K. Pinnion, P. Vaughan, D.A. Waller and M.L. Foster and "Long Term Experience With Bosentan for the Treatment of Idiopathic Pulmonary Arterial Hypertension Under Routine Conditions," by D.G. Kiely, J. Carlsen, M. Humbert, C. van Lierop and M.M. Hoeper.

Background: An increased prevalence of splenectomy has been reported in patients with idiopathic pulmonary arterial hypertension. Examination of small pulmonary arteries from these subjects has revealed multiple thrombotic lesions, suggesting that thrombosis may contribute to this condition. Based on these findings, we hypothesised that splenectomy could be a risk factor for chronic thromboembolic pulmonary hypertension (CTEPH), a condition defined by the absence of thrombus resolution after acute pulmonary embolism that causes sustained obstruction of the pulmonary arteries and subsequent pulmonary hypertension. Methods: The medical history, clinical characteristics, thrombotic risk factors and haemodynomics of 257 patients referred for CTEPH between 1989 and 1999 were reviewed. In a case-control study the prevalence of splenectomy in patients with CTEPH was compared with that of patients evaluated during the same period for idiopathic pulmonary hypertension (n = 276) or for lung transplantation in other chronic pulmonary conditions (n = 180). Results: In patients with CTEPH, 8.6% (95% CI 5.2 to 12.0) had a history of splenectomy compared with 2.5% (95% Cl 0.7 to 4.4) and 0.56% (95% CI 0 to 1.6) in cases of idiopathic pulmonary arterial hypertension and other chronic pulmonary conditions, respectively (p<0.01). Conclusion: Splenectomy may be a risk factor for chronic thromboembolic pulmonary hypertension. [ABSTRACT FROM AUTHOR]

This article focuses on congenital anomalies of coronary arteries. The classification of primary forms of coronary artery anomalies varies between ectopic origin of the coronary arteries from the aortic sinus, stenosis of the coronary arteries, absence of a coronary artery, to anomalous origin of the left or right coronary artery from the pulmonary artery or congenital coronary artery fistula. Both coronary arteries arising from the pulmonary trunk constitute an extremely rare situation. In such cases symptoms appear within a few days of birth, and death follows within two weeks; it is compatible with life only if associated with pulmonary hypertension.

Objectives: To validate in vivo a magnetic resonance imaging (MRI) method for measurement of pulmonary vascular resistance (PYR) and subsequently to apply this technique to patients with pulmonary hypertension (PHT). Methods and results: PVR was assessed from velocity encoded cine MRI derived pulmonary artery (PA) How volumes and simultaneously determined invasive PA pressures. For pressure measurements flow directed catheters were guided under magnetic resonance fluoroscopy at 1.5 T into the PA. In preliminary validation studies (eight swine) PVR was determined with the thermodilution technique and compared with PVR obtained by MRI (0.9 (0.5) v 1.1 (0.3) Wood units·m², p = 0.7). Bland-Altman test showed agreement between both methods. inter-examination variability was high for thermodilution (6.2 (2.2)%) but low for MRI measurements (2.1 (0.3)%). After validation, the MRI method was applied in 10 patients with PHI and five controls. in patients with PHT PYR was measured at baseline and during inhalation of nitric oxide. Compared with the control group, PVR was significantly increased in the PHI group (1.2 (0.8) v 13.1 (5.6) Wood units·m² , p < 0.001) but decreased significantly to 10.3 (4.6) Wood units·m² during inhalation of nitric oxide (p < 0.05). inter-examination variability of MRI derived PYR measurements was 2.6 (0.6)%. In all experiments (in vivo and clinical) flow directed catheters were guided successfully into the PA under MRI control. Conclusions: Guidance of flow directed catheters into the PA is feasible under MRI control. PVR can be determined with high measurement precision with the proposed MRI technique, which is a promising tool to assess PVR in the clinical setting. [ABSTRACT FROM AUTHOR]

Background: The effect of hypoxia on the formation of superoxide (O2-), the expression of gp91phox and endothelial NO synthase (eNOS) were studied in pig intact pulmonary artery (PA) segments and PA vascular smooth muscle cells (PAVSMCs) and PA endothelial cells (PAECs). Methods: Segments and cells were incubated under hypoxic conditions for 2 hours (with or without enzyme inhibitors) and the formation of O2- measured spectrophotometrically. Protein expression was assessed using Western blotting and immunocytochemistry. Results: Hypoxia promoted the formation of O2- in PA segments, PAVSMCs and PAECs, an effect inhibited by diphenylene iodonium and apocynin (NAD[P]H oxidase inhibitors). Hypoxia induced O2- formation was enhanced by inhibition of eNOS and augmented by endotoxin and cytokines and re-oxygenation. Hypoxia also promoted the expression of gp91phox and eNOS. In intact PA segments hypoxia induced the expression of nitrotyrosine and eNOS in the endothelium. Conclusions: The simultaneous upregulation of NAD[P]H oxidase and eNOS in response to hypoxia in the PA results in the simultaneous formation of O2-, NO, and ONOO-. This may represent either a protective mechanism designed to counter the pro-oxidant effect of hypoxia or a novel pathological mechanism underlying the progression of acute respiratory distress syndrome (ARDS). [ABSTRACT FROM AUTHOR]

Objectives: To report six month outcome in patients undergoing their first pulmonary vein ablation procedure for idiopathic atrial fibrillation (AF) at a "non-pioneering" hospital. Design: Prospective observational study. Setting: Specialist electrophysiology unit at a university hospital. Patients: The first 100 consecutive patients undergoing their first pulmonary vein catheter ablation procedure for highly symptomatic, drug resistant AF in the period 1999-2002. Main outcome measures: Incidence of symptomatic or asymptomatic, Holter documented AF six months after oblation. Results: Mean patient age was 52 years (range 23-73 years), mean length of AF history 53 months (range 6-180 months), mean number of antiarrhythmic drug failures was 3 (range 1-5), and 81 were men. At the time of the ablation procedure, 64 had progressed to persistent AF and 23 had increased transverse left atrial diameter. The number of pulmonary veins ablated in each patient was one in 11, two in 45, three in 36, and four in 8. Six months after ablation, 55 patients were consistently in sinus rhythm, asymptomatic, and without any Holter evidence of AF. The chance of being in sinus rhythm was 73% (29 of 64) in those with paroxysmal as compared with only 45% (26 of 36) in those with persistent AF at the time of ablation (p = 0.01). Outcome was not influenced by patient age, length of AF history, or duration of persistent AF before ablation or to left atrial dimension. Follow up was complete and no patient has died or experienced a stroke during or after ablation; nor have any developed symptoms of late pulmonary vein stenosis. However, other complications occurred during or shortly after the procedure in 12 patients, including cardiac tamponade in six. Conclusions: In selected patients with drug resistant AF, focal pulmonary vein catheter ablation offers a realistic prospect of achieving stable sinus rhythm compared with alternatives. However, it is a complex form of ablation with a significant risk of serious complications. Although a new milestone in arrhythmia management, the optimum ablation technique is still evolving and any impact on the natural history of AF remains to be determined. [ABSTRACT FROM AUTHOR]

The article presents some papers related to clinical aspects of pulmonary vascular disease. The study investigates the validation of pulmonary arterial hypertension, specific health related quality of life, and quality of life scores against haemodynamic and functional assessment of disease severity. It has been shown a statistically significant correlation between activity, symptom and quality of life scores, as described by patients and functional capacity measured by 6MWD. There was also a statistically significant correlation between patient described symptom score and invasive haemodynamic measurement.

Background: Chronic thromboembolic pulmonary hypertension (CTEPH) can be successfully treated surgically by pulmonary thromboendarterectomy (PTE) but there are few data on mid-term cardiopulmonary function, particularly on exertion, and clinical benefits following pulmonary PTE.Methods: A 2 year follow up study was undertaken of clinical status, haemodynamic and lung function indices, gas exchange, and exercise tolerance in 38 patients of mean (SD) age 50 (15) years who had undergone PTE.Results: In-hospital mortality was about 10%. Before PTE all the patients were severely impaired (NYHA classes III-IV). There was no time difference in the improvement in the parameters: nearly all the improvement in cardiac output, gas exchange, and clinical status was achieved in the first 3 months as a result of the relief of pulmonary obstruction. At 3 months the percentage of patients with normal cardiac output and PaO(2) and of those with reduced clinical impairment increased to 97%, 59%, and 87%, respectively, without any further change. Only mean pulmonary artery pressure (mPAP), carbon monoxide transfer factor (TLCO), and exercise tolerance improved gradually during the second year, probably due to the recovery of the damaged small vessels. TLCO was overestimated before PTE but afterwards the trend was similar to that of mPAP.Conclusions: At mid term only a few patients did not have a satisfactory recovery because of lack of operative success, hypertension relapse, or the effect of preoperative hypertension on vessels in non-obstructed segments. Most of the patients, even the more compromised ones, had excellent long lasting results. [ABSTRACT FROM AUTHOR]

Background: As there is controversy about changes in lung function in primary pulmonary hypertension (PPH), lung mechanics were assessed with a focus on expiratory airflow in relation to pulmonary haemodynamics.Methods: A cross sectional study was performed in 64 controls and 171 patients with PPH (117 women) of mean (SD) age 45 (13) years, pulmonary artery pressure (PAPmean) 57 (15) mm Hg, and pulmonary vascular resistance 1371 (644) dyne.s/cm(5).Results: Mean (SD) total lung capacity was similar in patients with PPH and controls (98 (12)% predicted v 102 (17)% predicted, mean difference -4 (95% confidence interval (CI) -7.89 to -0.11); residual volume (RV) was increased (118 (24)% predicted v 109 (27)% predicted, mean difference 9 (95% CI 1.86 to 16.14); and vital capacity (VC) was decreased (91 (16)% predicted v 102 (10)% predicted, mean difference -11 (95% CI 15.19 to -6.80). RV/TLC was increased (117 (27)% predicted v 97 (29)% predicted, mean difference 20 (95% CI 12.3 to 27.8)) and correlated with PAPmean (r=0.31, p<0.001). In patients with PAPmean above the median of 56 mm Hg, RV/TLC was further increased (125 (32)% predicted v 111 (22)% predicted, mean difference -14 (95% CI -22.2 to -5.8)). Expiratory flow-volume curves were reduced and curvilinear in patients with PPH.Conclusions: Peripheral airway obstruction is common in PPH and is more pronounced in severe disease. This may contribute to symptoms. Reversibility of bronchodilation and relation to exercise capacity need further evaluation. [ABSTRACT FROM AUTHOR]

Background: The design of devices currently used for closure of persistent ductus arteriosus (PDA) with high pulmonary artery pressure is not ideal and there is a risk of embolisation into the aorta.Objective: To investigate the use of the Amplatzer muscular ventricular septal defect occluder (AMVSDO) for treatment of PDA with high pulmonary artery pressure.Patients and Design: Seven patients, aged 5-12 years, with large PDAs and systemic or near systemic pulmonary artery pressure underwent attempted transcatheter closure using the AMVSDO. The device consists of two low profile disks made of a nitinol wire mesh with a 7 mm connecting waist. Balloon occlusion of the duct was performed before closure from the venous side, and prosthesis size was chosen according to the measured diameter of the occluding balloon. A 7 French sheath was used to deliver the device. All patients underwent a complete haemodynamic and angiographic study one year after occlusion.Results: The mean (SD) angiographic PDA diameter was 9.8 (1.7) mm (range 7-13 mm) and the mean AMVSDO diameter was 11.4 (1.8) mm (range 9-16 mm). Q(p)/Q(s) ranged from 1.9-2.2 (mean 2.0 (0.1)). Successful device delivery and complete closure occurred in all patients (100% occlusion rate, 95% confidence interval 59.04% to 100.00%). Mean systolic pulmonary artery pressures were as follows: before balloon occlusion, 106 (13) mm Hg; during occlusion, 61 (6) mm Hg; immediately after the procedure, 57 (5) mm Hg; and at the one year follow up catheterisation, 37 (10) mm Hg. Fluoroscopy time was 10.4 (4.3) min (range 7-18 min). No complications occurred.Conclusions: AMVSDO is an important adjunct for closure of large PDAs associated with high pulmonary artery pressure. Further studies are required to document its efficacy, safety, and long term results in a larger number of patients. [ABSTRACT FROM AUTHOR]

This article presents various studies that explore different aspects of pulmonary vascular disease. An ex-vivo isolated, perfused and ventilated human lung model is ideal for many physiological, biochemical and surgical studies in cancer. Prostacyclin is an effective treatment for pulmonary hypertension, however, increased doses are required to maintain efficacy. There was a significant improvement in the median gradient of changes in exercise capacity during treatment compared to pre treatment.

Objective: To determine whether inhaled NO (iNO) can reduce pulmonary vascular resistance in adults with congenital heart disease and obstructive pulmonary hypertension or Eisenmenger syndrome.Design: 23 patients received graded doses of iNO. Pulmonary and systemic haemodynamic variables and circulating cyclic guanosine monophosphate (cGMP) concentrations were measured at baseline and after 20 and 80 ppm iNO. Patients were considered responders when total pulmonary resistance was reduced by at least 20%, and rebound was defined as a greater than 10% increase in total pulmonary resistance upon withdrawal from iNO.Results: In response to 20 ppm iNO, total pulmonary resistance decreased in four patients (18%, 95% confidence interval (CI), 2% to 34%), while in response to 80 ppm iNO it decreased in six patients (29%, 95% CI 10% to 38%). Systemic blood pressure did not change. Withdrawal resulted in rebound in three patients (16%, 95% CI 0% to 32%) after cessation of 20 ppm iNO, and in six patients (35%, 95% CI 12% to 58%) after cessation of 80 ppm iNO. Patients with predominant right to left shunting did not respond. In all patients cGMP increased from (mean (SD)) 28 (13) micromol/l at baseline to 55 (30) and 78 (44) micromol/l after 20 and 80 ppm iNO (p < 0.05 v baseline).Conclusions: NO inhalation is safe and is associated with a dose dependent increase in circulating cGMP concentrations. Pulmonary vasodilatation in response to iNO was observed in 29% of patients and was influenced by baseline pulmonary haemodynamics. Responsiveness to acute iNO may identify patients with advanced obstructive pulmonary hypertension and Eisenmenger syndrome who could benefit from sustained vasodilator treatment. [ABSTRACT FROM AUTHOR]

Examines the hypersensitivity of lung vessels to catecholamines on patients with systemic hypertension pressure. Comparison between the pulmonary vascular reactivity on patients; Evaluation of the response to catecholamines; Influence of alterations of vascular receptors on the hypersensitivity of lung.

This report describes two cases of segmental pulmonary vein occlusion secondary to lung malignancy in which lung biopsies showed histological features of veno-occlusive disease. These are the first cases to be reported in the literature in which such lung parenchymal histological changes are described in association with lung malignancy. [ABSTRACT FROM AUTHOR]

Background: A study was undertaken to investigate the compliance with and accuracy of peak flow diaries in childhood asthma.Methods: Forty asthmatic children (5-16 years) were asked to perform peak flow measurements twice daily for 4 weeks by means of an electronic peak flow meter and to record values in a written diary. Patients and parents were unaware that the device stored the peak flow values on a microchip. In random order, half of the patients were only told that the device allowed for more accurate assessment of peak flow while the other half were told that accurate recording of peak flow was important because the results would be used in guiding adjustments to treatment. Data in the written diary (reported data) were compared with those from the electronic diary (actual data).Results: In the entire study population the mean (SD) actual compliance (77.1 (20.5)%) was much lower than the mean reported compliance (95.7 (9.1)%) (95% CI for difference 12.7% to 24.4%) The percentage of correct peak flow entries decreased from 56% to <50% from the first to the last study week (p<0.04), mainly as a result of an increase in self-invented peak flow entries. Results were comparable for both groups. For incorrect peak flow entries the mean difference between written and electronically recorded entries ranged from -72 to 34 l/min per patient.Conclusions: Peak flow diaries kept by asthmatic children are unreliable. Electronic peak flow meters should be used if peak flow monitoring is required in children with asthma. [ABSTRACT FROM AUTHOR]

In this article, the author discusses the accurate estimation of cardiac output and the oxygen consumption in children and adults with congenital and acquired heart disease. Topics discussed include calculation of pulmonary vascular resistance (PVR) on cardiac catheterisation, measurement of oxygen consumed directly by the lung tissue, and use of thermodilution method for estimation in congenital heart disease (CHD).

The authors report a novel case of exercise-induced haemoptysis with an unexpected underlying pathology. The report discusses the case and provides a pragmatic overview of the diagnosis and management of the pulmonary vein stenosis. [ABSTRACT FROM AUTHOR]

Introduction Elevated levels of inflammatory cytokines are associated with idiopathic and heritable pulmonary hypertension (PAH) and predict mortality, but their role in the pathobiology of PAH and the underlying mechanisms remain unclear. We investigated whether loss of bone morphogenetic protein receptor type II (BMPR-II), the underlying cause of heritable PAH, predisposes to increased inflammatory cytokine expression and pulmonary vascular remodelling. Methods Regulation of cytokine expression by lipopolysaccharide (LPS) was studied in two in vitro models: (1) mouse pulmonary artery smooth muscle cells (PASMCs) heterozygous for a null allele in bmpr2 (BMPR2±), and (2) human PASMCs with a mutation in BMPR2 (BMPR2mut) and their wild-type counterparts. Cytokine production, regulation and effects on the pulmonary vascular system were examined in an in vivo model using the bmpr2± mouse. Results Both mouse and human in vitro models showed that loss of BMPR2 function leads to increased mRNA expression and secretion of interleukin 6 and IL-8 both at baseline and after stimulation with LPS. This was associated with loss of expression of antioxidant enzymes such as superoxide dismutase 1 (SOD1) and SOD3, which is demonstrable in both mouse bmpr2± and human BMPR2mut cells. Treatment with the superoxide dismutase-mimetic, Tempol, partially reversed the exaggerated cytokine response to LPS but did not affect the underlying baseline increase. We demonstrated increased phospho-Stat3 signalling and pro-proliferative and pro-survival effects of IL-6 in BMPR2mut PASMCs which is not seen in the wild-type. This was confirmed in the in vivo model, as bmpr2± mice demonstrated increased IL-6 and IL-8 expression in sera, lung and liver tissue 3 and 24 h after exposure to 10 µg of LPS. A similar pattern of antioxidant enzyme reduction was also seen in lung tissue from these LPS-treated bmpr2± mice. Conclusions Loss of BMPR-II predisposes to both an abnormal increase in IL-6 and IL-8 after stimulation with LPS and a dysfunctional response to these cytokines in PASMCs and mice. The mechanism for this involves loss of antioxidant function. This abnormal response may underlie the additional lung-specific trigger that promotes the development of PAH in patients with BMPR-II mutations, and may represent a target for future therapeutic interventions. [ABSTRACT FROM AUTHOR]

The article highlights the results of a research on a case series of ductal stenting with a median follow-up of 12 months. It examines ductal stenting for restricted pulmonary blood flow in neonates. The article suggests that while postaglandins are almost always highly effective at maintaining duct patency medically in the short term, they become less reliable and have more side effects if given long term.

The article presents a study which indicates that circumferential pulmonary vein isolation (CPVI) can be introduced in the treatment of atrial fibrillation (AF) in laboratories with experienced electrophysiologists with promising and reproducible outcome and safety. The effectiveness rate for CPVI was similar to results from other centres. Investigators have reported a success rate of up to 90% AF freedom after CPVI depending on AF classification.

Presents various articles published in recent editions of major medical journals. Article on long term anticoagulation and venous thromboembolism in the "Journal of the American Medical Association"; Article on pulmonary artery catheters and mortality rates of intensive care patients in "Lancet"; Article on antibiotic susceptibility testing and cystic fibrosis in "Lancet"; Others.

Pulmonary hypertension frequently complicates mitral stenosis. Increased pulmonary artery pressure results from raised left atrial pressure, pulmonary arteriolar constriction, and obliterative changes in the pulmonary vascular bed, and usually responds to surgical relief of mitral stenosis. However, severe pulmonary hypertension may persist after surgical treatment of mitral stenosis. We describe a patient whose severe pulmonary hypertension following mitral valve replacement was treated successfully with continuous intravenous epoprostenol. [ABSTRACT FROM AUTHOR]

A response from the author of the article "Pulmonary vascular volumes and airways obstruction in SCD patients" in the current issue is presented.

The article presents a case study of a 56-year-old woman with unique pattern of bilateral, anomalous, curvilinear pulmonary vessels. It reports the demonstration of bilateral pulmonary veins through CT (Computerized Tomography) with volume-rendered reconstruction, coronal and axial maximum intensity projection (MIP) images. It discusses the impact of benign malformation of anomalous pulmonary veins on left-to-right shunt.

Background Pulmonary vein (PV) reconnection is the Achilles heel of pulmonary vein isolation (PVI) for atrial fibrillation (AF). Dissociated pulmonary vein potentials (dPVP) may reflect abnormal PV automaticity, indicate more extensive PV muscular sleeve or may simply be an epiphenomenon. Objective This study sought to determine the incidence, characteristics and prognostic significance of dPVP following PVI for AF. Methods 89 consecutive patients (mean age 58.2±8.4⇔…years, 75% male, 74% paroxysmal, 26% persistent AF) underwent antral PVI using three-dimensional mapping systems with image integration with the endpoint of bidirectional PV block. Following PV electrical isolation the presence and characteristics of dPVP were recorded. Holter monitoring was performed at 3, 6 and 12⇔…months. Acute PV reconnection was assessed over a 30-min waiting period. Results Electrical isolation was achieved in all 372 PV targeted for ablation. 69 of 372 isolated PV (19%) demonstrated dPVP after acute electrical isolation. Sites of dPVP origin were the left superior in 36%, left inferior in 20%, right superior in 31% and right inferior in 12%. All 69 dPVP demonstrated slow activity (cycle length >1500⇔…ms) with only four persisting more than 30⇔…min after acute isolation. There was no difference in the clinical characteristics between dPVP-positive vs dPVP-negative patients. At a mean follow-up of 21±8⇔…months the single procedure success was 25/33 (76%) in dPVP-positive versus 39/60 (64%) in dPVP-negative patients (p=⇔'0.3). In the eight dPVP-positive patients who underwent a second procedure, 11 of the 14 (79%) veins with initial dPVP demonstrated PV-left atrial reconnection. Conclusion dPVP are present in 19% of PV following acute antral electrical isolation. The presence of dPVP did not predict recurrent AF following PVI. [ABSTRACT FROM AUTHOR]

The article presents a pulmonary artery hypertension examination conducted to a 68-year-old woman. To investigate the cause of this disease, a CT pulmonary angiogram, a cardiac MRI, and a catheter angiogram were performed, its images are showed. It infers that most ruptures of the right pulmonary artery occur in the middle or lower lobe branches and carry a mortality rate up to 50%. Treatment using transcatheter embolisation is recommended.

A personal narrative which explores the author's experience pulmonary veins is presented.

Several images of giant coronary-pulmonary artery fistula with multiple saccular aneurysms are presented.

The article summarizes a study by M. Nguyen and colleagues on the benefits of Na+K+Cl cotransporter (NKCC1) inhibition in sepsis. The study found that NKCC1 contributes to changes in pulmonary vascular permeability during inflammation and loss of NKCC1 expression shows a protective effect against hypothermic sepsis and bacteremia.

The article analyzes the vulnerability of pulmonary capillaries to mechanical failure during strenuous exercise. Such mechanical failures are possible when the capillary wall stresses as a result of severe exercise. This can cause the integrity of the blood-gas barrier to break the stress. The exercise induced pulmonary hemorrhage in the galloping racehorses is an example for capillary stress failure. The pulmonary artery wedge pressures can rise to 30 mm Hg during intense exercise while giving an induced strain to the capillary walls.

The article presents a case of a 63-year old-patient with drug refractory paroxysmal atrial fibrillation. Previous clinical and echocardiographic information suggested that the heart was structurally normal. A complex, unsuspected coronary artery to pulmonary artery fistula was diagnosed and clearly delineated using three-dimensional volume rendering software.