Long-Term Bosentan in Chronic Thromboembolic Pulmonary Hypertension

Performance-based outcome measures for assessing physical capacity in patients with pulmonary embolism: A scoping review

INTRODUCTION

Up to 50 % of patients surviving a pulmonary embolism (PE) report persisting shortness of breath, reduced physical capacity and psychological distress. As the PE population is heterogeneous compared to other cardiovascular patient groups, outcome measures for assessing physical capacity traditionally used in cardiac populations may not be reliable for the PE population as a whole. This scoping review aims to 1) map performance-based outcome measures (PBOMs) used for assessing physical capacity in PE research, and 2) to report the psychometric properties of the identified PBOMs in a PE population.

METHODS

The review was conducted according to the Joanna Briggs Institute framework for scoping reviews and reported according to the PRISMA-Extension for Scoping Reviews guideline.

RESULTS

The systematic search of five databases identified 4585 studies, of which 243 studies met the inclusion criteria. Of these, 185 studies focused on a subgroup of patients with chronic thromboembolic pulmonary hypertension. Ten different PBOMs were identified in the included studies. The 6-minute walk test (6MWT) and cardiopulmonary exercise test (CPET) were the most commonly used, followed by the (Modified) Bruce protocol and Incremental Shuttle Walk test. No studies reported psychometric properties of any of the identified PBOMs in a PE population.

CONCLUSIONS

Publication of studies measuring physical capacity within PE populations has increased significantly over the past 5-10 years. Still, not one study was identified, reporting the validity, reliability, or responsiveness for any of the identified PBOMs in a PE population. This should be a priority for future research in the field.

Effect of riociguat on right ventricular function in patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

BACKGROUND

In the Phase III PATENT-1 (NCT00810693) and CHEST-1 (NCT00855465) studies, riociguat demonstrated efficacy vs placebo in patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). Clinical effects were maintained at 2 years in the long-term extension studies PATENT-2 (NCT00863681) and CHEST-2 (NCT00910429).

METHODS

This post hoc analysis of hemodynamic data from PATENT-1 and CHEST-1 assessed whether riociguat improved right ventricular (RV) function parameters including stroke volume index (SVI), stroke volume, RV work index, and cardiac efficiency. REVEAL Risk Score (RRS) was calculated for patients stratified by SVI and right atrial pressure (RAP) at baseline and follow-up. The association between RV function parameters and SVI and RAP stratification with long-term outcomes was assessed.

RESULTS

In PATENT-1 (n = 341) and CHEST-1 (n = 238), riociguat improved RV function parameters vs placebo (p < 0.05). At follow-up, there were significant differences in RRS between patients with favorable and unfavorable SVI and RAP, irrespective of treatment arm (p < 0.0001). Multiple RV function parameters at baseline and follow-up were associated with survival and clinical worsening-free survival (CWFS) in PATENT-2 (n = 396; p < 0.05) and CHEST-2 (n = 237). In PATENT-2, favorable SVI and RAP at follow-up only was associated with survival and CWFS (p < 0.05), while in CHEST-2, favorable SVI and RAP at baseline and follow-up were associated with survival and CWFS (p < 0.05).

CONCLUSION

This post hoc analysis of PATENT and CHEST suggests that riociguat improves RV function in patients with PAH and CTEPH.

Interventional and pharmacological management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by obstruction of the pulmonary vasculature, leading to increased pulmonary vascular resistance and ultimately right ventricular failure, the leading cause of death in non-operated patients. This article reviews the current management of CTEPH. The standard of care in CTEPH is pulmonary endarterectomy (PEA). However, up to 40% of patients with CTEPH are ineligible for PEA, and up to 51% develop persistent/recurrent PH after PEA. Riociguat is currently the only medical therapy licensed for treatment of inoperable or persistent/recurrent CTEPH after PEA based on the results of the Phase III CHEST-1 study. Studies of balloon pulmonary angioplasty (BPA) have shown benefits in patients with inoperable or persistent/recurrent CTEPH after PEA; however, data are lacking from large, prospective, controlled studies. Studies of macitentan in patients with inoperable CTEPH and treprostinil in patients with inoperable or persistent/recurrent CTEPH showed positive results. Combination therapy is under evaluation in CTEPH, and long-term data are not available. In the future, CTEPH may be managed by PEA, medical therapy or BPA - alone or in combination, according to individual patient needs. Patients should be referred to experienced centers capable of assessing and delivering all options.

Comparison of Balloon Pulmonary Angioplasty and Pulmonary Vasodilators for Inoperable Chronic Thromboembolic Pulmonary Hypertension: A Systematic Review and Meta-Analysis

Treatment options for chronic thromboembolic pulmonary hypertension (CTEPH) that is not amenable to thromboendarterectomy or is recurrent/persistent after thromboendarterectomy (inoperable CTEPH) include pulmonary vasodilators or balloon pulmonary angioplasty (BPA). We compared efficacy and safety outcomes of BPA with or without pulmonary vasodilators to pulmonary vasodilator therapy alone in patients with inoperable CTEPH. Observational and randomized trial data reporting outcomes for >5 patients with inoperable CTEPH were sought. Single-arm random effects meta-analyses were performed. The primary outcome was change in six-minute walk distance (6MWD). Secondary outcomes included safety; World Health Organization functional class (WHO FC); and change in mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), and cardiac index. Thirty-four studies with 1604 patients were eligible for analyses. Both treatments resulted in significant improvement in 6MWD (71.0 meters, 95% CI: 47.4–94.5 meters with BPA versus 47.8 meters, 95% CI: 34.5–61.2 meters with pulmonary vasodilators), PVR [−3.1 Wood Units (WU), 95% CI: −4.9 to −1.4 WU versus −1.6 WU, 95% CI: −2.4 to −0.8 WU] and mPAP (−14.8 mmHg, 95% CI: −18.2 to −11.5 mmHg versus −4.9 mmHg, 95% CI: −6.9 to −2.8 mmHg). Cardiac index was similar and most patients were WHO FC II and III after their respective interventions. More complications occurred in the BPA arm. In conclusion, BPA and pulmonary vasodilators both improve 6MWD and hemodynamics in patients with inoperable CTEPH. While BPA may offer greater functional and hemodynamic improvements, this technique carries the accompanying risks of an invasive procedure.

Chronic Thromboembolic Pulmonary Hypertension: Epidemiology, Diagnosis, and Management

Chronic thromboembolic pulmonary hypertension (CTEPH), classified as World Health Organization (WHO) group 4 pulmonary hypertension (PH), is an interesting and rare pulmonary vascular disorder secondary to mechanical obstruction of the pulmonary vasculature from thromboembolism resulting in PH. The pathophysiology is complex, beginning with mechanical obstruction of the pulmonary arteries, which eventually leads to arteriopathic changes and vascular remodeling in the nonoccluded arteries and in the distal segments of the occluded arteries mediated by thrombus nonresolution, abnormal angiogenesis, endothelial dysfunction, and various local growth factors. Based on available data, CTEPH is a rare disease entity occurring in a small proportion (0.5-3%) of patients after acute pulmonary embolism with an annual incidence ranging anywhere between 1 and 7 cases per million population. It is often underdiagnosed or misdiagnosed as idiopathic pulmonary arterial hypertension due to a lack of clinical suspicion or the under-utilization of radionuclide ventilation/perfusion scan. Although the current standard remains planar ventilation/perfusion scintigraphy as the initial imaging study to screen for CTEPH, and invasive pulmonary angiography with right heart catheterization as confirmatory modalities, they are likely to be replaced by modalities that can provide both anatomic and functional data while minimizing radiation exposure. Surgery is the gold standard treatment and offers better improvements in clinical and hemodynamic parameters compared with medical therapy. The management of CTEPH requires a multidisciplinary team, operability assessment, experienced surgical center, and the consideration of medical PH-directed therapies in patients who have inoperable disease, in addition to supportive therapies. Although, balloon pulmonary angioplasty is gaining interest to improve pulmonary hemodynamics and symptoms in CTEPH patients not amenable to surgery, further investigative randomized studies are needed to validate its use. It is very important for the present-day physician to be familiar with the disease entity and its appropriate evaluation to facilitate early diagnosis and appropriate management.

Bosentan therapy for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: A systemic review and meta-analysis

BACKGROUND AND OBJECTIVE

Bosentan therapy has been recommended for pulmonary arterial hypertension (PAH) and might be beneficial for chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to evaluate the specific effects of bosentan for PAH and CTEPH.

MATERIALS AND METHODS

We performed a systemic review and meta-analysis of randomized controlled trials (RCTs), comparing efficacy and safety of bosentan treatment for PAH and CTEPH through major biomedical database.

RESULTS

A total of 10 RCTs including 1185 patients were enrolled. For PAH patients, bosentan prolonged 6-minute walk distance with a weighted mean difference of 35.7 m, reduced mean pulmonary arterial pressure by 5.7 mm Hg, increased cardiac index by 0.4 L/min/m2 , reduced pulmonary vascular resistance by 305.1 dyn·s/cm5 , prevented functional class from deterioration and reduced clinical worsening as compared with placebo. For CTEPH patients, bosentan improved cardiac index by 0.3 L/min/m2 and reduced pulmonary vascular resistance by 176.0 dyn·s/cm5 . Other efficacy outcomes regarding CTEPH did not attain statistical difference. For both PAH and CTEPH, there was no significant difference in mortality or adverse event between bosentan and placebo group. However, bosentan raised the risk of abnormal liver function in both PAH and CTEPH patients.

CONCLUSIONS

Bosentan is effective in treating PAH, whereas it improves only certain hemodynamic parameters of CTEPH. Incidence of liver function abnormality is higher in bosentan treatment.

Prevention and treatment of the chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is an uncommon and late complication of pulmonary embolism resulting from misguided remodelling of residual pulmonary thromboembolic material and small-vessel arteriopathy. CTEPH is the only form of pulmonary hypertension (PH) potentially curable by pulmonary endarterectomy (PEA). Unfortunately, several patients have either an unacceptable risk-benefit ratio for undergoing the surgical intervention or develop persistent PH after PEA. Novel medical and endovascular therapies can be considered for them. The soluble guanylate cyclase stimulator riociguat is recommended for the treatment of patients with inoperable disease or with recurrent/persistent PH after PEA. Other drugs developed for the treatment of other forms of PH, as prostanoids, phosphodiesterase-5 inhibitors and endothelin receptor antagonists have been used in the treatment of CTEPH, with limited benefit. Balloon pulmonary angioplasty is a novel and promising technique and is progressively emerging from the pioneering phase. Highly specialized training level and complex protocols of postoperative care are mandatory to consolidate the technical success of the surgical and endovascular intervention.

Medical management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) results from incomplete resolution of acute pulmonary emboli, organised into fibrotic material that obstructs large pulmonary arteries, and distal small-vessel arteriopathy. Pulmonary endarterectomy (PEA) is the treatment of choice for eligible patients with CTEPH; in expert centres, PEA has low in-hospital mortality rates and excellent long-term survival. Supportive medical therapy consists of lifelong anticoagulation plus diuretics and oxygen, as needed.

An important recent advance in medical therapy for CTEPH is the arrival of medical therapies for patients with inoperable disease or persistent/recurrent pulmonary hypertension after PEA. The soluble guanylate cyclase stimulator riociguat is licensed for the treatment of CTEPH in patients with inoperable disease or with recurrent/persistent pulmonary hypertension after PEA. Clinical trials of this agent have shown improvements in patients' haemodynamics and exercise capacity. Phosphodiesterase-5 inhibitors, endothelin receptor antagonists and prostanoids have been used in the treatment of CTEPH, but evidence of benefit is limited. Challenges in the future development of medical therapy for CTEPH include better understanding of the underlying pathology, end-points to monitor the condition's progress, and the optimisation of pulmonary arterial hypertension therapies in relation to diverse patient characteristics and emerging options such as balloon pulmonary angioplasty.

Medical Therapy Versus Balloon Angioplasty for CTEPH: A Systematic Review and Meta-Analysis

BACKGROUND

A significant number of chronic thromboembolic pulmonary hypertension (CTEPH) patients will have an inoperable disease. Medical therapy and balloon pulmonary angioplasty (BPA) have provided alternate therapeutic options for patients with inoperable CTEPH, although there are a limited number of published studies examining the outcomes. Thus, our study aims to evaluate and compare the efficacy of medical therapy and BPA in patients with inoperable CTEPH.

METHODS

An electronic search of six databases was performed and the search results were screened against established criteria for inclusion into this study. Data was extracted and meta-analytical techniques were used to analyse the data.

RESULTS

Pooled data from RCTs revealed that medical therapy, compared with a placebo, was associated with a significant improvement of at least one functional class (p=0.038). With regards to pulmonary haemodynamics, medical therapy also resulted in a significant reduction in both mean pulmonary arterial pressure (mPAP) (p=0.002) and pulmonary vascular resistance (PVR) (p<0.001). From the included observational studies, the 6-minute walk distance (6MWD) significantly increased following medical therapy by an average of 22.8% (p<0.001). The pooled improvement in 6MWD was found to be significantly higher in the BPA group when compared to medical therapy for CTEPH (p=0.001). Pooled data from available observational studies of medical therapy or BPA all demonstrated significant improvements in mPAP and PVR for pre versus post intervention comparisons. The improvement in mPAP (p=0.002) and PVR (p=0.002) were significantly greater for BPA intervention when compared to medical therapy.

CONCLUSIONS

High-quality evidence supports the use of targeted medical therapy in improving haemodynamics in patients with inoperable CTEPH. There is only moderate-quality evidence from observational studies supporting the efficacy of BPA in improving both haemodynamics and exercise capacity. Further RCTs and prospective observational studies comparing medical therapy and BPA in patients with inoperable CTEPH are required.

Chronic Thromboembolic Pulmonary Hypertension: the End Result of Pulmonary Embolism

Chronic thromboembolic pulmonary hypertension (CTEPH) occurs when a pulmonary embolism fails to undergo complete thrombolysis leading to vascular occlusion and pulmonary hypertension. Despite the fact that CTEPH is a potential consequence of pulmonary embolism, diagnosis requires a high degree of vigilance as many patients will not have a history of thromboembolic disease. The ventilation perfusion scan is used to evaluate for the possibility of CTEPH although right heart catheterization and pulmonary artery angiogram are needed to confirm the diagnosis. Pulmonary thromboendarterectomy is the first-line treatment for patients who are surgical candidates. Recently, riociguat has been approved for patients with nonsurgical disease or residual pulmonary hypertension despite surgical intervention. This review describes the pathophysiology, risk factors, diagnosis, and management of CTEPH.

Pharmacological therapy for patients with chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but life-threatening disease resulting from unresolved thromboembolic obstructions. Pulmonary endarterectomy (PEA) surgery is the gold-standard treatment as it is potentially curative; however, not all patients are deemed operable and up to one-third have persistent or recurrent CTEPH after the procedure. Pulmonary arterial hypertension (PAH) and CTEPH have similar clinical presentations and histopathological features, so agents shown to be effective in PAH have often been prescribed to patients with CTEPH in the absence of proven therapies. However, clinical evidence for this strategy is not compelling. A number of small uncontrolled trials have investigated endothelin receptor antagonists, prostacyclin analogues and phosphodiesterase type 5 inhibitors in CTEPH with mixed results, and a phase III study of the endothelin receptor antagonist bosentan met only one of its two co-primary end-points. Recently, however, the soluble guanylate cyclase stimulator, riociguat, was approved in the USA and Europe for the treatment of inoperable or persistent/recurrent CTEPH following positive results from the phase III CHEST study (Chronic Thromboembolic Pulmonary Hypertension Soluble Guanylate Cyclase–Stimulator Trial). This article reviews the current evidence for the use of pharmacological therapies in CTEPH.

A review of pharmacological treatment of inoperable or persistent/recurrent CTEPH and the future standard of carehttp://ow.ly/KMUQV

Developments in pulmonary arterial hypertension-targeted therapy for chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease characterised by the presence of organised chronic thromboembolic material occluding the proximal pulmonary arteries and a vasculopathy in the distal pulmonary arterial tree. Pulmonary endarterectomy (PEA) is a potential cure for many patients with CTEPH. However, PEA is not suitable for patients with a significant distal distribution of chronic thromboembolic material or with significant comorbidities. Also, a proportion of patients are left with residual CTEPH post PEA. Until recently, pulmonary arterial hypertension-targeted therapies have been used off licence to treat patients with inoperable or residual CTEPH. The CHEST1 study investigated the use of riociguat and was the first randomised controlled trial to show efficacy in inoperable or residual CTEPH. In this review, we explore the pathophysiology of CTEPH and review the current trial evidence for pulmonary arterial hypertension-targeted therapies. We also include a discussion of physiological considerations that require further investigation.

Diagnostic evaluation and management of chronic thromboembolic pulmonary hypertension: a clinical practice guideline

BACKGROUND

Pulmonary embolism is a common condition. Some patients subsequently develop chronic thromboembolic pulmonary hypertension (CTEPH). Many care gaps exist in the diagnosis and management of CTEPH patients including lack of awareness, incomplete diagnostic assessment, and inconsistent use of surgical and medical therapies.

METHODS

A representative interdisciplinary panel of medical experts undertook a formal clinical practice guideline development process. A total of 20 key clinical issues were defined according to the patient population, intervention, comparator, outcome (PICO) approach. The panel performed an evidence-based, systematic, literature review, assessed and graded the relevant evidence, and made 26 recommendations.

RESULTS

Asymptomatic patients postpulmonary embolism should not be screened for CTEPH. In patients with pulmonary hypertension, the possibility of CTEPH should be routinely evaluated with initial ventilation/perfusion lung scanning, not computed tomography angiography. Pulmonary endarterectomy surgery is the treatment of choice in patients with surgically accessible CTEPH, and may also be effective in CTEPH patients with disease in more 'distal' pulmonary arteries. The anatomical extent of CTEPH for surgical pulmonary endarterectomy is best assessed by contrast pulmonary angiography, although positive computed tomography angiography may be acceptable. Novel medications indicated for the treatment of pulmonary hypertension may be effective for selected CTEPH patients.

CONCLUSIONS

The present guideline requires formal dissemination to relevant target user groups, the development of tools for implementation into routine clinical practice and formal evaluation of the impact of the guideline on the quality of care of CTEPH patients. Moreover, the guideline will be updated periodically to reflect new evidence or clinical approaches.

Long-term efficacy of bosentan in inoperable chronic thromboembolic pulmonary hypertension

Background. Inoperable chronic thromboembolic pulmonary hypertension (CTEPH) is associated with a poor survival.Objectives. To evaluate the long-term response to a dual endothelin receptor antagonist in patients with inoperable CTEPH.Methods. All consecutive 18 patients (mean age 63+/-14 years) treated with bosentan for symptomatic inoperable CTEPH were included. Efficacy was evaluated by the log value of serum levels of N-terminal-pro brain natriuretic peptide (log NTpro BNP), New York Heart Association functional class (NYHA), and the six-minute walk test (6-MWT). All follow-up data (median 31 months) were compared with baseline and divided into: short-term (<12 months), mid-term (between 12 and 24 months), and long-term follow-up (>24 months).Results. At baseline, 15 patients were in NYHA class III and three in NYHA class IV, mean log NT-pro BNP level was 7.2+/-1.4 log pg/ml, and mean 6-MWT distance was 404+/-125 m. During short-term follow-up (n=18), the NYHA class improved (p=0.001), 6-MWT distance increased by 33 m (p=0.03), and log NT-pro BNP decreased to 6.9+/-1.4 log pg/ml (p=0.007). During mid-term follow-up (n=17), the NYHA class improved (p<0.001), the mean 6-MWT distance increased by 41 m (p=0.01), and log NT-pro BNP was 6.9+/-1.4 log pg/ml (p=0.31). During late followup (n=14) the NYHA class was still improved (p=0.03), the 6-MWT distance decreased by 9 m (p=0.73), and log NT-pro BNP was 7.1+/-1.5 log pg/ml (p=0.91). The overall four year survival rate was 88%.

CONCLUSION

Bosentan seems to be effective during long-term treatment in patients with inoperable CTEPH. (Neth Heart J 2009;17:329-33.).

Bosentan in pulmonary arterial hypertension: a comparison between congenital heart disease and chronic pulmonary embolism

Background. In patients with pulmonary hypertension, it is unknown whether the treatment effect of bosentan is dependent on the duration of pulmonary vessel changes. Therefore, we studied the response to bosentan in patients with life-long pulmonary vessel changes (pulmonary arterial hypertension (PAH) due to congenital heart disease (CHD)) and in patients with subacutely induced pulmonary vessel changes (chronic thromboembolic pulmonary hypertension (CTEPH)).Methods. In this open-label study, 18 patients with PAH due to CHD and 16 patients with CTEPH were treated with bosentan for at least one year. All patients were evaluated at baseline and during follow-up by means of the six-minute walk distance (6-MWD) and laboratory tests.Results. Improvement of 6-MWD was comparable in patients with PAH due to CHD (444+/-112 m to 471+/-100 m, p=0.02), and in CTEPH (376+/-152 m to 423+/-141 m, p=0.03) after three months of treatment. After this improvement, 6-MWD stabilised in both groups.Conclusion. Although duration of pulmonary vessel changes is strikingly different in patients with PAH due to CHD and CTEPH, the effect of one year of bosentan treatment was comparable. The main treatment effect appears to be disease stabilisation and decreasing the rate of deterioration. (Neth Heart J 2009;17:334-8.).

Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association

Venous thromboembolism (VTE) is responsible for the hospitalization of >250 000 Americans annually and represents a significant risk for morbidity and mortality. Despite the publication of evidence-based clinical practice guidelines to aid in the management of VTE in its acute and chronic forms, the clinician is frequently confronted with manifestations of VTE for which data are sparse and optimal management is unclear. In particular, the optimal use of advanced therapies for acute VTE, including thrombolysis and catheter-based therapies, remains uncertain. This report addresses the management of massive and submassive pulmonary embolism (PE), iliofemoral deep vein thrombosis (IFDVT),and chronic thromboembolic pulmonary hypertension (CTEPH). The goal is to provide practical advice to enable the busy clinician to optimize the management of patients with these severe manifestations of VTE. Although this document makes recommendations for management, optimal medical decisions must incorporate other factors, including patient wishes, quality of life, and life expectancy based on age and comorbidities. The appropriateness of these recommendations for a specific patient may vary depending on these factors and will be best judged by the bedside clinician.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is one of the few forms of pulmonary hypertension that is surgically curable. It is likely underdiagnosed and must be considered in every patient presenting with pulmonary hypertension to avoid missing the opportunity to cure these patients. This article discusses the epidemiology, risk factors, natural history, diagnosis, and preoperative evaluation of patients with this disorder. Also covered are putative mechanisms for the conversion of acute emboli into fibrosed thrombembolic residua. Mechanical obstruction of the central pulmonary vasculature is rarely the sole cause of the pulmonary hypertension, and a discussion of the small vessel arteriopathy present in these patients is offered. Technical aspects of pulmonary endartectomy and the data supporting its role are discussed, as are the limited data on pulmonary arterial hypertension specific medical therapies for patients deemed noncandidates for the operation.

[Medical treatment in patients with chronic thromboembolic pulmonary hypertension]

Pulmonary thromboendarterectomy is the treatment of choice in patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, specific medical treatment of pulmonary hypertension (PH) can be an alternative or play a complementary role to surgery. Thus, in patients unsuitable for surgery due to distal thrombotic obstruction, residual or persistent PH after surgery or very severe PH and a high-risk hemodynamic profile, medical treatment may improve their clinical course and the outcome of thromboendarterectomy. Patients with distal obstruction in the pulmonary tree and those with residual PH after surgery show clinical and hemodynamic deterioration due to progression of the pulmonary vascular disease in the smallcaliber arterioles. Conventional treatment with diuretics, anticoagulants and oxygen therapy has been demonstrated to have little effectiveness. In the last decade, numerous drugs have been developed for the treatment of PH: prostacyclin analogs, endothelin receptor antagonists, and phosphodiesterase-5 inhibitors acting principally in vascular remodelling of small-caliber arterioles. Although evidence of the effectiveness of these drugs in PH and the histological similarity of small-vessel vasculopathy in CTEPH to that of other forms of PH provide the main rationale for the use of these drugs in patients with CTEPH, the evidence from clinical trials is still limited.

Anaesthesia and right ventricular failure

Acute right ventricular (RV) failure has until recently received relatively little attention in the cardiology, critical care or anaesthesia literature. However, it is frequently encountered in cardiac surgical cases and is a significant cause of mortality in patients with severe pulmonary hypertension who undergo non-cardiac surgery. RV dysfunction may be primarily due to impaired RV contractility, or volume or pressure overload. In these patients, an increased pulmonary vascular resistance (PVR) or a decreased aortic root pressure may lead to RV ischaemia, resulting in a rapid, downward haemodynamic spiral. The key aspects of 'RV protection' in patients who are at risk of perioperative decompensation are prevention, detection and treatment aimed at reversing the underlying pathophysiology. Minimising PVR and maintaining systemic blood pressure are of central importance in the prevention of RV decompensation, which is characterised by a rising central venous pressure and a falling cardiac output. Although there are no outcome data to support any therapeutic strategy for RV failure when PVR is elevated, the combination of inhaled iloprost or intravenous milrinone with oral sildenafil produces a synergistic reduction in PVR, while sparing systemic vascular resistance. Levosimendan is a promising new inotrope for the treatment of RV failure, although its role in comparison to older agents such as dobutamine, adrenaline and milrinone has yet to be determined. This is also the case for the use of vasopressin as an alternative pressor to noradrenaline. If all else has failed, mechanical support of the RV should be considered in selected cases.

Chronic thromboembolic pulmonary hypertension: an updated review

PURPOSE OF REVIEW

Venous thromboembolism is a spectrum of disease comprising deep vein thrombosis, thrombus in transit, acute pulmonary embolism, and chronic thromboembolic pulmonary hypertension (CTEPH) as a rare and late possible sequela.

RECENT FINDINGS

On the basis of a prospective long-term study, the incidence of CTEPH is estimated at 3.8% within 2 years of all patients surviving an episode of symptomatic idiopathic pulmonary embolism. Young age, a large perfusion defect, and idiopathic clinical presentation are associated with a higher probability of CTEPH. Current pathophysiological concepts suggest a misguided thrombus resolution process that is triggered by infection, inflammation, autoimmunity, and malignancy. Diagnosis and therapy of CTEPH are interdisciplinary achievements and nowadays still based on a positive lung perfusion scan and for assessment of operability on a classical pulmonary angiography. Treatment of choice is surgical pulmonary endarterectomy of the pulmonary obstructions, which leads to restoration of normal pulmonary hemodynamics at rest in nearly 80% of patients. In expert centers, surgical mortality is under 10%.

SUMMARY

CTEPH has emerged as a 'dual' pulmonary vascular disorder with major vessel vascular remodeling of thrombus organization, combined with a small vessel pulmonary arteriopathy that is a target for classic vasodilator treatments.

Bosentan for patients with chronic thromboembolic pulmonary hypertension

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) is a progressive disease leading to worsening functional status and reduced survival for those patients who cannot undergo pulmonary endarterectomy (PEA). Pharmacotherapy with novel drugs for pulmonary hypertension may be useful in treating patients who are poor candidates for surgery, but there are still few clinical data on medical therapy for CTEPH. The aim of this prospective open-label, multicenter, study is to compare the efficacy of 1-year bosentan treatment to standard drugs in nonoperated patients with CTEPH.

PATIENTS AND METHODS

Thirty-four nonoperated patients with CTEPH were enrolled. Functional assessment included 6 minute walk test (6MWT), Borg index, WHO classification, arterial blood gases and echocardiography systolic pulmonary artery pressure (sPAP). Seventeen patients received bosentan (62.5 mg b.i.d. for 4 weeks and then 125 mg b.i.d.); 17 patients were treated with standard therapy alone.

RESULTS

At admission sPAP was 76.18+/-5.96 mmHg in bosentan group and 71.48+/-3.71 mmHg in controls, p(a)O(2) 64.68+/-2.25 mmHg in bosentan group, and 59.52+/-2.05 mmHg in controls, 6MWT 297.53+/-34.25 mt in bosentan group, and 268.47+/-36.54 mt in controls. After 12 months there were significant differences between the groups in the 6MWT (+57.24+/-22.21 m vs -73.13+/-21.23 m, p<0.001), dyspnoea index (Borg score 4.29+/-0.49 vs 7.06+/-0.32, p<0.001) and oxygenation (p(a)O(2) 65.93+/-3.76 mmHg vs 48.48+/-1.31 mmHg, p<0.001). The sPAP was stable after 12 months of bosentan (76.18+/-5.96 mmHg vs 71.00+/-5.41 mmHg, p=0.221) in contrast to controls (71.48+/-3.71 mmHg vs 80.44+/-4.70 mmHg, p=0.029).

CONCLUSION

The data of this open-label study in nonoperated CTEPH patients suggest an improvement in functional outcomes adding Bosentan to diuretics and oral anticoagulants. No improvement was observed using only standard drugs after 1-year.