Use of Pulmonary Arterial Hypertension Therapies in Patients with a Fontan Circulation: Current Practice Across the United Kingdom.

Background The Fontan circulation is a successful operative strategy for abolishing cyanosis and chronic volume overload in patients with congenital heart disease with single ventricle physiology. "Fontan failure" is a major cause of poor quality of life and mortality in these patients. We assessed the number and clinical characteristics of adult patients with Fontan physiology receiving pulmonary arterial hypertension (PAH) therapies across specialist centers in the United Kingdom. Methods and Results We identified all adult patients with a Fontan-type circulation under active follow-up in 10 specialist congenital heart disease centers in England and Scotland between 2009 and 2019. Patients taking PAH therapies were matched to untreated patients. A survey of experts was also performed. Of 1538 patients with Fontan followed in specialist centers, only 76 (4.9%) received PAH therapies during follow-up. The vast majority (90.8%) were treated with a phosphodiesterase-5 inhibitor. In 33% of patients, PAH therapies were started after surgery or during hospital admission. In the matched cohort, treated patients were more likely to be significantly limited, have ascites, have a history of protein-losing enteropathy, or receive loop diuretics (P<0.0001 for all), also reflecting survey responses indicating that failing Fontan is an important treatment target. After a median of 12 months (11-15 months), functional class was more likely to improve in the treated group (P=0.01), with no other changes in clinical parameters or safety issues. Conclusions PAH therapies are used in adult patients with Fontan circulation followed in specialist centers, targeting individuals with advanced disease or complications. Follow-up suggests stabilization of the clinical status after 12 months of therapy.

Echocardiographic Screening for Pulmonary Hypertension in Congenital Heart Disease: JACC Review Topic of the Week.

Echocardiography is the mainstay in screening for pulmonary hypertension (PH). International guidelines suggest echocardiographic parameters for suspecting PH, but these may not apply to many adults with congenital heart disease (ACHD). PH is relatively common in ACHD patients and can significantly affect their exercise capacity, quality of life, and prognosis. Identification of patients who have developed PH and who may benefit from further investigations (including cardiac catheterization) and treatment is thus extremely important. A systematic review and survey of experts from the United Kingdom and Ireland were performed to assess current knowledge and practice on echocardiographic screening for PH in ACHD. This paper presents the findings of the review and expert statements on the optimal approaches when using echocardiography to assess ACHD patients for PH, with particular focus on major subgroups: patients with right ventricular outflow tract obstruction, patients with systemic right ventricles, patients with unrepaired univentricular circulation, and patients with tetralogy of Fallot with pulmonary atresia.

Is the hypercoagulable state in atrial fibrillation mediated by vascular endothelial growth factor?

BACKGROUND AND PURPOSE: Tissue factor (TF; an initiator of coagulation) and vascular endothelial growth factor (VEGF; a marker of angiogenesis) are involved in the hypercoagulable state associated with malignancy. We investigated their roles in chronic atrial fibrillation (AF), a condition also associated with increased risk of stroke and thromboembolism, as well as a prothrombotic or hypercoagulable state. METHODS: We studied 25 patients with AF (20 men; mean+/-SD age, 62+/-13 years) who were compared with 2 control groups in sinus rhythm: 30 healthy control subjects (17 men; mean age, 60+/-9 years) and 35 patient control subjects with coronary artery disease (CAD; 27 men; mean age, 60+/-12 years). Plasma levels of TF, VEGF, and the VEGF receptor sFlt-1 were measured by enzyme-linked immunosorbent assay. RESULTS: VEGF, sFlt-1, and TF were significantly different between the 3 groups, with abnormal levels in AF and CAD patients compared with control subjects (P<0.001, P=0.022, and P=0.008, respectively). Among the AF patients, TF levels were significantly correlated with VEGF (Spearman's r=0.65, P<0.001) and sFlt (r=0.54, P=0.006) levels. Only TF and VEGF levels were significantly correlated in CAD patients (r=0.39, P=0.02). There were no significant correlations among the healthy control subjects. CONCLUSIONS: Patients with chronic AF have high TF levels, in keeping with the prothrombotic state associated with this arrhythmia. The relationships between TF and VEGF and its receptor sFlt-1 in AF suggest a possible role for VEGF in the hypercoagulable state found in AF, as seen in malignancy and atherosclerosis.

Relation of thrombogenesis in systemic hypertension to angiogenesis and endothelial damage/dysfunction (a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial [ASCOT]).

Increasing evidence points toward a prothrombotic state in hypertension and atherosclerosis, conditions associated with thrombosis-related complications, such as myocardial infarction and stroke. We hypothesized that this increased risk of thrombogenesis may be related to endothelial damage/dysfunction and abnormal angiogenesis, and thus, an increased risk of future cardiovascular disease. Thrombogenesis, endothelial damage/dysfunction, and angiogenesis can be assessed by measurement of tissue factor (TF), von Willebrand Factor (vWF), flow-mediated dilatation (FMD), and vascular endothelial growth factor (VEGF), respectively. To test this hypothesis, we measured TF, vWF, FMD, and VEGF in 76 patients with systemic hypertension (71 men; mean age 64; mean blood pressure 167/72 mm Hg), considered additional risk factors such as diabetes, and related them to the patient's 10-year cardiovascular and cerebrovascular risk score using the Framingham equation. Patients were compared with 48 healthy normotensive controls. In these patients, the effects of 6 months of intensified blood pressure and (where appropriate) lipid-lowering treatment were investigated. In our patients, TF, VEGF, and vWF levels were higher, but FMD was lower (all p <0.001) compared with the controls. All markers correlated with each other and with both cardiovascular and cerebrovascular risk scores (all p <0.001). After intensified blood pressure and hypercholesterolemia treatment, total cholesterol, blood pressure, TF, VEGF, and vWF levels all decreased, whereas FMD increased (all p <0.001). Thus, in subjects with hypertension and other risk factors, endothelial damage/dysfunction (and thus, atherogenesis), thrombogenesis, and angiogenesis are abnormal, correlate with overall cardiovascular risk, and importantly, can be related to each other in a "Birmingham Vascular Triangle." Furthermore, these processes are beneficially affected by intensive blood pressure and lipid treatment.

Thrombogenesis and endothelial damage/dysfunction in peripheral artery disease. Relationship to ethnicity and disease severity.

Peripheral artery disease (PAD) and intermittent claudication are common in men aged over 55 years. Once the diagnosis has been made, very few patients suffer from a deterioration of the disease. Those that do deteriorate tend to do so due to thrombosis of an affected artery. It is apparent that the disruption in the vessel wall accounts for some of the cause of the thrombosis but blood constituents also play a role. We hypothesized that levels of soluble P-selectin (sP-sel, a marker of platelet activation), von Willebrand factor (vWf, an index of endothelial damage/dysfunction), tissue factor (TF, a coagulation protein involved in the 'extrinsic' coagulation pathway) and fibrinogen would be abnormally elevated in relation to disease severity and correlated with each other, and related to ethnicity, in a multiethnic population of patients with PAD. To test this hypothesis, we studied 234 patients (80% white, 7% Indo-Asian, 13% Afro-Caribbean) with confirmed PAD [ankle brachial pressure index (ABPI)< or =0.8] and 50 healthy controls. All of the indices studied were increased in patients over controls (p<0.05). None of the indices of the hypercoagulable state were significantly different between the three ethnic groups studied. Patients with ischaemic rest pain were shown to have higher levels of plasma fibrinogen (p<0.001) although none of the other prothrombotic markers were increased in this group. Furthermore, fibrinogen was higher in cases whose ABPI was below the median (<0.52) when compared to those less severely affected, with an inverse correlation between fibrinogen and ABPI (Spearman, r=-0.178, p=0.009). In conclusion, we found a prothrombotic state in patients with PAD with increased levels of markers of endothelial damage/dysfunction, platelet activation and thrombosis, which may contribute to the pathogenesis of this condition. However, disease severity was only related to plasma fibrinogen levels.

Alterations of thrombogenesis, endothelial damage and oxidative stress with reperfusion during femoral artery bypass surgery for peripheral vascular disease.

Peripheral vascular disease (PVD) is a significant cause of cardiovascular morbidity. We hypothesised that there would be significant alterations of thrombogenesis, platelet activation and endothelial damage, which could be associated with abnormal oxidative stress during femoral artery bypass surgery for PVD, where the femoral artery is cross-clamped (causing acute ischaemia) and reperfused (following revascularisation). To test this hypothesis, we measured sequential changes in von Willebrand factor (vWF, and index of endothelial damage/dysfunction), tissue factor (TF, an index of thrombogenesis) and soluble P-selectin (sP-sel, an index of platelet activation) as well as lipid hydroperoxides (LPO, an index of oxidative stress) in 28 consecutive patients undergoing elective peripheral artery bypass surgery. Mean baseline vWF and sP-sel levels in PVD patients (before clamping) were significantly higher compared with age- and sex-matched controls (unpaired t test, both p < 0.05), but there were no significant differences in TF and LPO levels. There was a correlation between TF and vWF (Spearman's, r = 0.374, p = 0.05), as well as between sP-sel and vWF at the start of surgery (r = 0.467, p = 0.012). The patients undergoing peripheral artery bypass surgery had a mean femoral artery clamp time of 28 min (standard deviation 14 min; range 11-65 min). There were no significant overall changes in sP-sel, vWF, TF and LPO with femoral artery cross-clamping and reperfusion (repeated measures ANOVA, p = NS). In conclusion, we found that during ischaemia-reperfusion during peripheral arterial bypass surgery, thrombogenesis (as measured by plasma TF) and oxidative damage (as measured by LPO) within the affected leg does not increase in the immediate perioperative period. Further studies are required to assess the mechanism(s) of ischaemia-reperfusion injury in PVD, and the contributory role(s) of the endothelium and platelets.

Indices of thrombogenesis, endothelial damage and platelet function following percutaneous peripheral artery angiography and angioplasty for peripheral vascular disease.

We hypothesised that there would be alterations in markers of endothelial damage/dysfunction, platelet activation and thrombogenesis in patients with peripheral vascular disease (PVD) as a result of undergoing diagnostic angiography and therapeutic angioplasty. To test this hypothesis, we measured sequential changes in von Willebrand factor (vWf, an index of endothelial damage/dysfunction), tissue factor (TF, an index of thrombogenesis) and soluble P-selectin (sP-sel, an index of platelet activation) in 52 consecutive patients (32 male; mean age 69 years, SD 10) who were undergoing elective angiography and angioplasty for PVD. Patients with PVD had significantly higher vWf and sP-sel levels compared to healthy controls (both p < 0.001), but median TF levels were not significantly different (p = 0.344). In the whole group, there was a significant reduction in sP-sel levels (p < 0.001, paired t test) post-angiography/angioplasty, but no significant change in vWf and TF levels. In patients undergoing angiography only, there was a significant drop in mean sP-sel (p < 0.001, paired t test) and vWf (p = 0.044) values after the procedure, whilst TF levels were not significantly changed (p = 0.370, Mann-Whitney U test). In patients undergoing angioplasty and stent, mean sP-sel levels fell immediately after the procedure (p = 0.001, paired t test), but there were no statistically significant changes in vWf and TF-levels. In conclusion, there appears to be a reduction in plasma sP-sel levels following angioplasty and stenting for PVD, suggesting alterations in platelet physiology, which may be accompanied by some alterations in the endothelium. The possibility that these changes may have pathophysiological implications for understanding platelet and endothelial reactions to angiography and associated interventions (that is, angioplasty and stent) needs to be explored.

Assessment of endothelial damage in atherosclerotic vascular disease by quantification of circulating endothelial cells. Relationship with von Willebrand factor and tissue factor.

BACKGROUND: Increased numbers of CD146-defined circulating endothelial cells (CECs), as are present in the peripheral blood of patients suffering acute coronary syndromes, imply injury to the endothelium. Endothelial damage can also be assessed by the measurement of plasma levels of von Willebrand factor (vWf). Increased levels of procoagulant plasma tissue factor (TF), arising from monocytes/macrophages and endothelial cells, is present in atherosclerosis. We hypothesised increased CECs in patients with ischaemic rest pain (IRP) of the lower limb due to peripheral atherosclerosis and comparable to that seen in patients with acute myocardial infarction (AMI), when compared to patients with intermittent claudication (IC) or healthy controls that would correlate with vWf and TF. PATIENTS AND METHODS: We recruited 20 patients in each of four groups: (i) IRP of the lower limb; (ii) AMI; (iii) 'stable' IC; and (iv) healthy controls. CD146-expressing CECs were measured by immumomagnetic separation and counting under a fluorescence microscope; plasma vWf and TF by ELISA. RESULTS: In IRP, median (IQR) CEC levels were 3.5 (2.0-5.8) cells/ml, in IC were 1.1 (0.6-2.9) cells/ml, and in healthy controls were 1.0 (0.5-1.7) cells/ml (p<0.001). The levels of vWf (p=0.034) and TF (p=0.007) were also significantly different between the groups, with the highest levels in patients with IRP. Levels of CECs correlated with vWf (rs=0.4, p=0.002) and TF ( rs=0.296, p=0.021 ). In AMI, CEC levels were higher than those in IRP at 4.9 (3.6-8.4) cells/ml (p=0.0385). CONCLUSION: This study demonstrates evidence of direct endothelial cell injury (i.e. raised CECs) in patients with IRP that correlated with vWf and TF, but that this is less severe than in AMI.