Chronic thromboembolic pulmonary hypertension global cross-sectional scientific survey (CLARITY) – interim results on the adoption and perception of guidelines

Background

The chronic thromboembolic pulmonary hypertension (CTEPH) global cross-sectional scientific survey (CLARITY) was established to provide insights into current clinical practices and unmet needs in the diagnosis and treatment of CTEPH. The European Society of Cardiology (ESC) plays a leading role in establishing guidelines (GLs) for clinical decision-making in acute pulmonary embolism (PE) and CTEPH. It is of interest to better understand how these GLs affect real-world practice.

Purpose

To assess the adoption and perception of clinical practice GLs among medical specialists working in the fields of cardiology.

Methods

The online survey was developed by an independent committee of 11 international CTEPH experts using the Delphi method and designed to elicit responses regarding disease awareness and management, including follow-up after acute PE and diagnosis of suspected CTEPH. Logic functions were implemented to ensure respondents only viewed questions relevant to their clinical practice. To date, professional members of 17 Scientific Societies and other medical organizations were invited to respond to the survey. For this interim analysis response data were collected from 10.09.2021 to 10.02.2022.

Results

Out of 242 respondents, 107 specialized in cardiology (44%) and 7 specialized in angiology (3%) were included in this interim analysis. Respondents were from Europe (75%, n=85), Asia Pacific (20%, n=23) and the Americas (5%, n=6) and generally had 15–29 (40%, n=45) or 5–14 (37%, n=42) years of working experience. Of the 67 respondents (59%) that did not work in a pulmonary hypertension (PH)/CTEPH expert centre, only 24 (36%) were affiliated with such a centre.

Of respondents involved in acute PE management (n=101) and CTEPH diagnosis (n=87), 87 (86%) and 71 (82%) reported following the 2019 PE ESC/European Respiratory Society (ERS) and 2015 PH ESC/ERS GLs, respectively. Regardless of country, a higher proportion of respondents from Asia Pacific also reported using national GLs for PE (44%, n=10) and CTEPH (52%, n=12) compared to respondents from Europe (15%, n=11; 25%, n=15) and the Americas (25%, n=1; 40%, n=2). Overall, GLs were perceived to facilitate clinical practice (Fig. 1).

Lack of GLs to screen for CTEPH following acute PE was more often reported as a barrier by respondents from Asia Pacific and those working in an expert centre. Low adherence to GLs was reported as a barrier to CTEPH diagnosis by approximately 1/3 of respondents, irrespective of care setting, and in higher proportion among those with more working experience.

Conclusion

Despite the availability of GLs, reported barriers indicate an opportunity for educational activities to improve adoption and adherence to GLs. Observed differences and potential gaps between clinical practice and the GLs warrant further exploration through additional global insights collected by the survey throughout April 2022.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This survey is sponsored by Actelion Pharmaceuticals Ltd, a Janssen Pharmaceutical Company of Johnson & Johnson

Chronic thromboembolic pulmonary hypertension and left ventricular filling pressures

Background

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by chronic obstruction of major pulmonary arteries with organized thrombi and is classified as pre-capillary pulmonary hypertension (PH) by the current hemodynamic definition of the guidelines. However, clinical risk factors for PH due to left heart disease including features of the metabolic syndrome, left-sided valvular heart disease and stable ischemic heart disease can be frequently observed in patients with CTEPH. The aim of this study was to investigate the prevalence, mechanisms and prognostic implications of elevated left ventricular filling pressures (LVFP) in patients with CTEPH.

Methods

394 consecutive CTEPH patients undergoing a first diagnostic right and left heart catheterization were included in this study. mPAWP and LVEDP were utilized for assessment of LVFP. Two cutoffs were applied to identify patients with elevated LVFP: (1) mPAWP and/or LVEDP >15 mmHg as recommended by the current PH guidelines and (2) mPAWP and/or LVEDP >11 mmHg, which is the upper limit of normal in healthy subjects. Clinical and echocardiographic features as well as long-term mortality data were assessed.

Results

LVFP was >15 mmHg in 41 (10.4%) and >11 mmHg in 155 patients (39.3%). Univariable logistic regression analysis identified age, body mass index, systemic hypertension, diabetes, atrial fibrillation, mitral regurgitation and left atrial volume as significant clinical predictors of elevated LVFP. Systemic hypertension, atrial fibrillation, mitral regurgitation and left atrial volume remained independent determinants of LVFP in adjusted analysis. LVFP >11 mmHg was associated with worse long-term survival (p-logrank = 0.020).

Conclusions

Elevated LVFP is common in patients with CTEPH at the time of diagnosis. Elevated LVFP in CTEPH appears to be due to comorbid left heart disease. CTEPH patients with LVFP >11 mmHg have worse outcomes.

Funding Acknowledgement

Type of funding sources: None.

The prognostic value of vasoresponse to nitric oxide in patients with chronic thromboembolic pulmonary hypertension

Background

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by pulmonary artery obstructions due to organized chronic thrombotic material in major pulmonary arteries. In addition, about half of the patients suffer from a small vessel pulmonary arteriopathy that is a strong predictor of outcomes. Currently available treatment of CTEPH includes interventional strategies such as pulmonary endarterectomy (PEA) and balloon pulmonary angioplasty (BPA), and non-interventional strategies with PH-specific medications. A simple way of assessing small vessel disease is the degree of vasodilation (“vasoresponse”) in response to inhaled nitric oxide (iNO). In idiopathic pulmonary arterial hypertension vasoresponse serves as the best marker for good prognosis and treatment selection. In CTEPH, the prognostic value of vasoresponse remains unclear.

Purpose

We investigated the prognostic value of three definitions of vasoresponse to nitric oxide in patients with CTEPH.

Methods

We studied 325 CTEPH patients who underwent baseline diagnostic right heart catheterization (RHC) with 40ppm iNO testing at a general hospital (AKH) between 1995 and 2019. Cox regression models, adjusting for covariates including age, sex, comorbidities, and markers for disease severity at baseline, such as proBNP, GFR, NYHA functional class, were used to determine the risk of death or lung transplantation with respect to vasoresponse. We analysed three currently used definitions of vasoresponse to nitric oxide – the classical definition (CD) as a 10mmHg reduction in mPAP to a level below 40mmHg; an absolute definition (AD) as a 10mmHg reduction in mPAP regardless of resulting mPAP; and the percent definition (PD) as a 10% reduction in mPAP regardless of resulting mPAP.

Results

Patients had a median age of 62 (interquartile range [IQR]: 50, 71) at time of baseline right heart catheterization and 50% were female. During a median observation time of 5 years (IQR: 2.2, 9.0), the combined endpoint of death or lung transplantation occurred in 88 cases (27%). In the cox regression model PD vasoresponders, showed improved survival when undergoing PEA (p=0.0019). In PD vasoresponsive patients who were not given PEA surgery (n=66), PH medication therapy was associated with improved survival (p=0.0053), whereas BPA had no association with survival (p=0.58). In PD non-vasoresponsive patients who were not given PEA surgery (n=107) BPA improved survival (p<0.0001), whereas PH medication therapy did not improve survival (p=0.08).

Conclusion

The PD vasoresponse to iNO carries valuable prognostic information about freedom from death or lung transplantation in patients with CTEPH. In patients who are not eligible for PEA, PD vasoresponse can improve optimal therapy selection.

Funding Acknowledgement

Type of funding sources: None.

Response to anticoagulation in chronic thromboembolic pulmonary hypertension

Introduction

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by fibrotic thrombus in the pulmonary arteries, likely originating from pulmonary embolism. Inadequate anticoagulation is one of the suspected mechanisms of disease in CTEPH. The aim of our study was to assess phenprocoumon dosing and genetic polymorphisms of vitamin K epoxide reductase complex subunit 1 (VKORC 1) that are known to affect the dose required to reach therapeutic range.

Methods

The ratio of mean weekly phenprocoumon dose in relation to mean INR levels was assessed in CTEPH patients on phenoprocoumon oral anticoagulation for at least 6 months, compared with PAH patients. VKORC 1 (–1639, –3730) single nucleotide polymorphisms (SNPs) were determined by polymerase chain reaction (PCR).

Results

In 225 patients (167 CTEPH, 58 PAH) mean treatment duration was 51.7±44.7 months, and mean age was 62.9±13.87 years (49.7% female). Median weekly dose of phenprocoumon was 10.5 mg (IQR 9.0–16.5) for PAH vs. 14.25 mg (IQR 10.5–18.0) in the CTEPH cohort (p=0.016). Although median INR was not significantly different among the two groups (2.28 vs. 2.40 in the PAH vs. CTEPH, respectively, p=0.084), achieving the mentioned INR require significantly higher weekly doses in the CTEPH group. While distribution of VKORC1 variants was according to the Hardy Weinberg equilibrium, patients with CTEPH and VKORC1 –1639 GG homozygous wild type required significantly higher phenprocoumon doses compared with VKORC1 –1639 AA homozygous mutants (P<0.001).

Conclusion

CTEPH patients require more vitamin K antagonists in relation to INR levels than PAH patients. Unmet phenprocoumon dosing requirements may be one mechanism of disease in CTEPH.

Funding Acknowledgement

Type of funding sources: None.

Efficacy and safety of percutaneous pulmonary artery subtotal occlusion and CTO intervention in chronic thromboembolic pulmonary hypertension

Background

Balloon pulmonary angioplasty (BPA) is an emerging percutaneous therapy for patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH), and patients with mean pulmonary artery pressure (mPAP) ≤30mmHg have an excellent survival. Common vascular lesion types are ring-like stenoses (type A), web lesions (type B), subtotal occlusions (type C), chronic total occlusions (CTO, type D) and tortuous lesions (type E). Occlusive lesions (i.e. subtotal occlusions and CTOs) are most challenging. While the CTO intervention the coronary arteries remains controversial, risk and benefit of pulmonary artery occlusive lesion intervention in CTEPH has not been studied yet. We evaluated the impact of percutaneous pulmonary artery subtotal occlusion and CTO intervention on BPA treatment response.

Methods

120 patients underwent 712 BPA procedures between April 2014 and October 2019. Clinical features and hemodynamics were assessed at baseline and 6–12 months after the last BPA session.

Results

A total of 2542 lesions were targeted; 720 occlusions (28.3%; 352 CTOs and 368 subtotal occlusions) and 1822 non-occlusion lesions (71.7%). Complications occurred in 6.0% of all procedures (severe complications in 0.4% of all procedures). 45 patients completed BPA treatment after a median of 6 (4; 10) procedures per patient. In these patients, mPAP dropped from 40.1±10.8 to 25.6±5.1mmHg (p<0.001), without significant change in cardiac output (5.2±1.4 to 5.5±3.1L/min, p=0.409). In the overall cohort, success rate for recanalization of occlusions was 81% (subtotal occlusions (type C lesions): 98%; CTOs (type D lesions) 50%). Number of successfully treated lesions of any type (β −0.86 [−1.19; −0.53]; p<0.001), number of successfully treated occlusions (β −2.17 [−3.38; −0.97]; p=0.001) and number of successfully treated non-occlusion lesions (β −0.81 [−1.25; −0.37]; p<0.001) emerged as predictors of relative change in mPAP. The impact on relative change in mPAP was higher for CTOs (β −5.88 [−10.49; −1.26]; p=0.014) than for subtotal occlusions (β −2.51 [−4.18; −0.83]; p=0.004).

Conclusions

The number of successfully treated vascular lesions predicts treatment response to BPA. The number of successfully recanalized occlusions (particularly CTOs) appears to have the strongest impact on change in mPAP, highlighting the importance of advanced BPA technique.

Funding Acknowledgement

Type of funding sources: None. Visual overview

Lowering of mean pulmonary arterial pressure is a prognostic marker in pulmonary hypertension patients treated with subcutaneous treprostinil

Background

Treprostinil (TRE), a prostacyclin analog, is effective for the treatment of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension (CTEPH). We hypothesized that change of hemodynamics is of prognostic value. In our prospective registry we evaluated effects of first-line subcutaneous (sc) TRE in patients with severe pulmonary hypertension (PH) and analyzed the prognostic value of hemodynamic changes from baseline on long-term follow-up.

Methods

Data was collected from patients with pre-capillary PH in WHO functional class III or IV, mean right atrial pressure of ≥10mmHg, and/or cardiac index ≤2.2 liters/min/m2. Patients received first-line scTRE. Dose adjustments were performed individually according to clinical symptoms and side effects.

Results

Between 1999 and 2018 138 patients were treated. Of these, 18 (13%) patients underwent double lung transplantation, and 59 (42.8%) died of any cause. Overall survival rates at 1, 5, 10, and 15 years were 91%, 57%, 31% and 29%. The strongest predictor of outcome was change in mPAP after one year of scTRE. Change in mPAP (−18.4±7.9 mmHg) was associated with the best subsequent survival of 12.7±1.5 years.

Conclusion

The data suggest that patients benefit from aggressive lowering of mPAP in the first year of treatment.

Funding Acknowledgement

Type of funding source: None

The role of asymmetric dimethylarginine (ADMA) in the follow-up of patients with precapillary pulmonary hypertension (PH)

Introduction

Asymmetric dimethylarginine (ADMA) interferes with L-arginine in the production of nitric oxide, a key mediator of endothelial cell function. ADMA is elevated in pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) and is associated with unfavorable outcomes.

Aim

To assess the role of ADMA to monitor disease progression of PH patients treated with PAH-specific therapy.

Methods

ADMA was measured by competitive ELISA at baseline (BL) and follow-up (FU). Risk assessment including a clinical assessment, echocardiography, 6-minute walking test, NT-pro-BNP and hemodynamic assessment by right heart catheterization was performed accordingly. Risk was calculated according to the ESC/ERS 2015 guidelines by the SPHAR method.

Results

ADMA samples were collected from 113 patients treated at our institution between 2012 and 2019. 89 (79%) patients had PAH, 15 (13%) were diagnosed with CTEPH and 9 (8%) with group 3 – PH associated with lung disease. 69% were females. 15 (13.3%) patients had a low risk at baseline, 96 (85%) intermediate risk and 2 (1.8%) were high risk patients. 75% received oral medications, 31% received subcutaneous treprostinil. Median baseline ADMA was 0.738umol/l. At BL no significant difference of ADMA plasma levels was found among the different PH types (p=0.063), or between different risk categories (p=0.531).

Change in ADMA plasma levels correlated with change in risk (p=0.002, rs 0.291) and with change in mixed venous saturation (p=0.034, rs −0.205). Change in ADMA plasma levels also correlated with risk at FU (p=0.011, rs 0.240).

Patients categorized as low risk at FU had a median ADMA plasma level decrease of 22%, compared with −3 to 0% ADMA plasma level change in patients with moderate to high risk at FU (p=0.04). Patients who improved their risk category had a median decrease of ADMA plasma level of 23% vs. 2.3% in patients who did not improve (p=0.011). Decrease of ADMA plasma levels was a weak but significant discriminator for improvement of risk in ROC analysis (p=0.032, AUC 0.374).

Conclusion

ADMA plasma levels paralleled the hemodynamic and clinical benefit of PAH-specific treatments in patients with precapillary PH. ADMA could be used as a biomarker for monitoring treatment effects in precapillary PH.

Funding Acknowledgement

Type of funding source: None

P4160Safety and efficacy of triple combination therapy with parenteral prostanoids in patients with Eisenmenger physiology

Aim

While combination therapy is currently strongly advocated for idiopathic pulmonary arterial hypertension (PAH) patients, evidence to support its use in patients with PAH related to congenital heart disease (CHD), especially patients with Eisenmenger syndrome, is lacking. We evaluated the efficacy and safety of sequential triple combination therapy with parenteral prostanoids after failure of double oral therapy in patients with PAH-CHD and Eisenmenger physiology.

Methods

This is an international, multicentre, retrospective cohort study conducted in adult patients with Eisenmenger physiology on double oral PAH therapy in whom intravenous or subcutaneous prostanoid treatment was added due to clinical deterioration or failure to reach the treatment goals. Clinical status, 6-minute walk test distance (6MWD), biomarkers and haemodynamics were assessed at baseline and during the follow-up.

Results

A total 28 patients with Eisenmenger syndrome (6 [21%] male, age 37.6±14.3 years) were included. A post-tricuspid shunt was present in 16 (57%), 86% of whom had a ventricular septal defect. The majority (89%) were treated with subcutaneous treprostinil. At 27±14 months follow-up, WHO functional class improved in 18 (64%), remained unchanged in 8 (29%), and deteriorated in 2 (7%) patients. There was also an increase in 6MWD (mean 339±145 versus 233±140m, p=0.0001, fig 1A) and a reduction in NT-proBNP levels (median 1125 [123–5882] versus 3087 [234–7428] pg/mL, p<0.0001, fig 1B). On follow-up cardiac catheterization, an improvement in right atrial pressure (8±2 versus 11±5 mmHg, p=0.01), mean pulmonary artery pressure (68±12 versus 72±17 mmHg, p=0.005), cardiac index (2.3±0.3 versus 2.0±0.5 l/min/m2, p=0.005, fig 1C), and pulmonary vascular resistance (17±7 versus 21±10, p=0.008, fig 1D), was observed compared to baseline. No patients discontinued treatment. Five (18%) patients died during follow up.

Figure 1

Conclusions

Triple combination therapy with subcutaneous treprostinil or endovenous epoprostenol in patients with Eisenmenger syndrome is safe and well tolerated at 2 years follow-up, resulting in a significant improvement in clinical status, exercise tolerance and haemodynamics.

A noninvasive algorithm to exclude pre-capillary pulmonary hypertension

Current guidelines recommend right heart catheterisation (RHC) in symptomatic patients at risk of pre-capillary pulmonary hypertension (PH) with echocardiographic systolic pulmonary artery pressures ≥ 36 mmHg. Growing awareness for PH, a high prevalence of post-capillary PH and the inability to distinguish between pre- and post-capillary PH by echocardiography have led to unnecessary RHCs. The aim of our study was to assess whether standard noninvasive diagnostic procedures are able to safely exclude pre-capillary PH. Data from 251 patients referred for suspicion of pre-capillary PH were used to develop a noninvasive diagnostic decision tree. A prospectively collected data set of 121 consecutive patients was utilised for temporal validation. According to the decision tree, patients were stratified by the presence or absence of an electrocardiographic right ventricular strain pattern (RVS) and serum N-terminal brain natriuretic peptide (NT-proBNP) levels below and above 80 pg·mL⁻¹. In the absence of RVS and elevated NT-proBNP, none of the patients in the prospective validation cohort were diagnosed with pre-capillary PH by RHC. Combining echocardiography with the diagnostic algorithm increased specificity to 19.3% (p = 0.0009), while sensitivity remained at 100%. Employing ECG and NT-proBNP on top of echocardiography helps recognise one false positive case per five patients referred with dyspnoea and echocardiographic suspicion of PH, while not missing true pre-capillary PH.

Risk factors for chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterised by nonresolving pulmonary thromboemboli that can be treated by surgical pulmonary endarterectomy (PEA). The authors of the present study sought to confirm known and to identify novel CTEPH risk factors in a controlled retrospective cohort study of prevalent CTEPH cases collected in three European centres offering PEA. Data from CTEPH patients were compared with nonthromboembolic pre-capillary pulmonary arterial hypertension cohorts at the participating institutions. The study population comprised 687 patients assessed at the time of diagnosis between 1996 and 2007. Ventriculo-atrial shunts and infected pacemakers (odds ratio (OR) 76.40, 95% confidence interval (CI) 7.67-10,351), splenectomy (OR 17.87, 95% CI 1.56-2,438), previous venous thromboembolism (VTE; OR 4.52, 95% CI 2.35-9.12), recurrent VTE (OR 14.49, 95% CI 5.40-43.08), blood groups other than 0 (2.09, 95% CI 1.12-3.94), and lupus anticoagulant/antiphospholipid antibodies (OR 4.20, 95% CI 1.56-12.21) were more often associated with CTEPH. Thyroid replacement therapy (OR 6.10, 95% CI 2.73-15.05) and a history of malignancy (OR 3.76, 95% CI 1.47-10.43) emerged as novel CTEPH risk factors. In conclusion, the European database study confirmed previous knowledge of chronic thromboembolic pulmonary hypertension risk factors, and identified thyroid replacement therapy and a history of malignancy as new medical conditions associated with chronic thromboembolic pulmonary hypertension.

Heart-type fatty acid-binding protein for risk assessment of chronic thromboembolic pulmonary hypertension

Heart-type fatty acid-binding protein (H-FABP) is a reliable marker of myocardial injury and was recently identified as a predictor of outcome in acute pulmonary embolism. The aim of the present study was to investigate the prognostic value of H-FABP in chronic thromboembolic pulmonary hypertension (CTEPH). In total, 93 consecutive patients with CTEPH were studied. During long-term follow-up (median duration 1,260 days, interquartile range (IQR) 708-2,460 days), 46 (49%) patients had an adverse outcome, defined as CTEPH-related death, lung transplantation or persistent pulmonary hypertension after pulmonary endarterectomy (PEA). Baseline H-FABP levels in plasma ranged from 0.69-24.3 ng x mL(-1) (median (IQR) 3.41 (2.28-4.86) ng x mL(-1)). Cox regression analysis revealed a hazard ratio of 1.10 (95% confidence interval 1.04-1.18) for each increase of H-FABP by 1 ng x mL(-1), and continuous elevations of H-FABP emerged as an independent predictor of adverse outcome by multivariable analysis. PEA was performed in 52 patients and favourably affected the long-term outcome. Kaplan-Meier analysis revealed that patients with baseline H-FABP concentrations >2.7 ng x mL(-1), the median value of the biomarker in the surgically treated population, had a lower probability of event-free survival after PEA. Heart-type fatty acid-binding protein is a promising novel biomarker for risk stratification of patients with chronic thromboembolic pulmonary hypertension.

Treprostinil for severe inoperable chronic thromboembolic pulmonary hypertension

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) results from non-resolving pulmonary thromboemboli that are resistant to plasmatic anticoagulation. Because of a secondary pulmonary arteriopathy accompanying major vessel obstruction, the disorder may be a target for vasodilator therapy.

OBJECTIVES

In an open-label uncontrolled study, we investigated the prostacyclin analog treprostinil given s.c. in patients with severe inoperable CTEPH.

METHODS

Between September 1999 and September 2005, 25 patients were included if their World Health Organization (WHO) functional class was III or IV, if their six-minute walking distance (6-MWD)

RESULTS

Treprostinil-treated patients demonstrated significant improvements in 6-MWD (P = 0.01), WHO functional class (P = 0.001), B-type brain natriuretic peptide plasma levels (P = 0.02), cardiac outputs (P = 0.007) and pulmonary vascular resistances (P = 0.01) after 19 +/- 6.3 months. Treprostinil plasma concentrations correlated with drug dose (P < 0.001), indicating stable absorption over time. Long-term survival was significantly better than in controls.

CONCLUSIONS

Treprostinil improves exercise capacity, hemodynamics and survival in patients with severe inoperable CTEPH. We speculate that the effects may be explained by a combined vasodilatory, platelet-antagonistic and potential antiproliferative action of the drug.

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MESH Headings

• Aged
• Antihypertensive Agents/administration & dosage
• Antihypertensive Agents/blood
• Antihypertensive Agents/therapeutic use
• Cardiac Output/drug effects
• Case-Control Studies
• Chronic Disease
• Epoprostenol/administration & dosage
• Epoprostenol/analogs & derivatives
• Epoprostenol/blood
• Epoprostenol/therapeutic use
• Female
• Follow-Up Studies
• Humans
• Hypertension, Pulmonary/blood
• Hypertension, Pulmonary/drug therapy
• Hypertension, Pulmonary/etiology
• Hypertension, Pulmonary/mortality
• Infusion Pumps
• Kaplan-Meier Estimate
• Male
• Middle Aged
• Natriuretic Peptide, Brain/blood
• Odds Ratio
• Pain/drug therapy
• Pain/etiology
• Pain Measurement
• Platelet Aggregation Inhibitors/administration & dosage
• Platelet Aggregation Inhibitors/blood
• Platelet Aggregation Inhibitors/therapeutic use
• Proportional Hazards Models
• Prospective Studies
• Pulmonary Embolism/blood
• Pulmonary Embolism/complications
• Pulmonary Embolism/drug therapy
• Pulmonary Embolism/mortality
• Risk Assessment
• Severity of Illness Index
• Thromboembolism/blood
• Thromboembolism/complications
• Thromboembolism/drug therapy
• Thromboembolism/mortality
• Time Factors
• Treatment Outcome
• Vascular Resistance/drug effects
• Vasodilator Agents/administration & dosage
• Vasodilator Agents/blood
• Vasodilator Agents/therapeutic use
• Walking

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Bosentan therapy for pulmonary arterial hypertension associated with hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT) is a disorder of arteriovenous malformations and telangiectases. In rare cases affected individuals may develop typical pulmonary arterial hypertension (PAH). Vasodilator therapy has not been recommended because of a potential increase in arteriovenous shunt volume. This report is on two patients with severe HHT-associated PAH who were treated with bosentan, an oral endothelin ET(A)/ET(B) receptor antagonist. After 1 year, symptomatic and functional improvements were confirmed by haemodynamic evaluation demonstrating a significant decrease of mean pulmonary artery pressures and an increase in cardiac index, without evidence for an increase in effective shunt volume.