Interventional and Surgical Modalities of Treatment in Pulmonary Hypertension

A Novel Chitosan-coated Leciplex Loaded with Ambrisentan as a Possible Pulmonary Nanosystem: Optimization, Characterization, and Pharmacokinetics Assessments

The purpose of this research was to formulate, optimize, and characterize ambrisentan chitosan-coated LeciPlex (AMS-CTS-LPX) to increase the therapeutic effectiveness and bioavailability of ambrisentan. A central composite design (CCD) was implemented to assess the impact of various factors on the production of AMS-CTS-LPX and to identify the optimum formulation via the use of Design Expert® software. The assembly of AMS-CTS-LPX was conducted using a single-step process. Subsequently, the optimal formulation was chosen and subjected to further assessments. Further, a comparative pharmacokinetic study was carried out using a rat model. The optimized formulation exhibited an entrapment efficiency of 82.39%, with a diameter of 137.53 nm and a surface charge of +43.65 mV. Additionally, it had a sustained cumulative release of 90.41% after 8 h and showed good stability. The safety of AMS-CTS-LPX administered intratracheally was confirmed by in vivo histopathological studies. The pharmacokinetic investigations revealed a 5.6-fold increase in the bioavailability of AMS from the optimal AMS-CTS-LPX formulation compared to the oral AMS solution. Collectively, the results of the current study suggest that CTS-LPX may be beneficial as a pulmonary nanosystem for the administration of AMS.

Antiphospholipid Syndrome in Patients with Venous Thromboembolism

Unprovoked (or provoked by mild risk factors) venous thromboembolism (VTE) in young patients, VTE in uncommon sites, or cases of unexplained VTE recurrence may be positive for antiphospholipid antibodies (aPL) and thus may be diagnosed with antiphospholipid syndrome (APS). The evaluation of aPL is standardized using immunological tests for anticardiolipin and anti-β2-glycoprotein I. The determination of functional antibodies (lupus anticoagulant) is less standardized, especially in patients on anticoagulant treatment. Patients positive for all the three tests are at high risk of recurrence, which, in turn, might lead to chronic obstruction of pulmonary vessels (chronic thromboembolic pulmonary hypertension). Randomized clinical trials have shown that triple-positive patients should be treated with vitamin K antagonists maintaining an international normalized ratio between 2 and 3. Whether patients with VTE and incomplete aPL profile can be treated with direct oral anticoagulants should be further investigated.

Clinical Outcomes of Endoscope-Assisted Pulmonary Endarterectomy for Chronic Thromboembolic Pulmonary Hypertension

PURPOSE

Pulmonary thromboembolism is a potentially life-threatening condition in patients with heart disease; however, limited studies discussing long-term outcomes exist. This study aimed to investigate the long-term outcomes of pulmonary endarterectomy (PEA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH), focusing on the improvement of functional class and right ventricular (RV) pressure.

MATERIALS AND METHODS

Clinical data of patients with CTEPH were obtained from Yonsei Hospital between May 2012 and December 2021, and reviewed retrospectively. Twenty-six patients underwent endoscope-guided PEA during the study period, and the mean follow-up duration was 24.8±23.4 months.

RESULTS

After PEA, most patients (88.5%) were weaned from inotropes without extracorporeal membrane oxygenation support during the first few days. Two patients (7.6%) had cerebrovascular accidents without neurological deficits. On echocardiography, the RV systolic pressure and tricuspid regurgitation grades significantly improved (p<0.001). Furthermore, the mean left ventricle end-diastolic diameter was significant increased (p=0.003), and the left ventricular end-systolic diameter increased (p<0.001). The median intensive care unit stay was 3.0±9.4 days, and median hospital stay 16.0±26.5 days. The 5-year survival rate was 95.5%, and the 5-year freedom rate of cardiac death was 100%. There was a marked improvement in New York Heart Association (NYHA) status (p<0.001). Cox regression suggested that the main pulmonary artery (MPA) involvement is a significant predictor of non-improvement in functional class post-PEA.

CONCLUSION

Mortality rates are low and patients experience a marked improvement in NYHA class and health status after PEA. Moreover, MPA involvement may affect functional outcomes.

Large animal preclinical investigation into the optimal extracorporeal life support configuration for pulmonary hypertension and right ventricular failure

INTRODUCTION

Right ventricular failure (RVF) is a major cause of mortality in pulmonary hypertension (PH). Mechanical circulatory support holds promise for patients with medically refractory PH, but there are no clinical devices for long-term right ventricular (RV) support. Investigations into optimal device parameters and circuit configurations for PH-induced RVF (PH-RVF) are needed.

METHODS

Eleven sheep underwent previously published chronic PH model. We then evaluated a low-profile, ventricular assist device (VAD)-quality pump combined with a novel low-resistance membrane oxygenator (Pulmonary Assist Device, PAD) under one of four central cannulation strategies: right atrium-to-left atrium (RA-LA, N = 3), RA-to-pulmonary artery (RA-PA, N=3), pumpless pulmonary artery-to-left atrium (PA-LA, N = 2), and RA-to-ascending aorta (RA-Ao, N = 3). Acute-on-chronic RVF (AoC RVF) was induced, and mechanical support was provided for up to 6 hours at blood flow rates of 1 to 3 liter/min. Circuit parameters, physiologic, hemodynamic, and echocardiography data were collected.

RESULTS

The RA-LA configuration achieved blood flow of 3 liter/min. Meanwhile, RA-PA and RA-Ao faced challenges maintaining 3 liter/min of flow due to higher circuit afterload. Pumpless PA-LA was flow-limited due to anatomical limitations inherent to this animal model. RA-LA and RA-Ao demonstrated serial RV unloading with increasing circuit flow, while RA-PA did not. RA-LA also improved left ventricular (LV) and septal geometry by echocardiographic assessment and had the lowest inotropic dependence.

CONCLUSION

RA-LA and RA-Ao configurations unload the RV, while RA-LA also lowers pump speed and inotropic requirements, and improves LV mechanics. RA-PA provide inferior support for PH-RVF, while an alternate animal model is needed to evaluate PA-LA.

Comprehensive Review of Pulmonary Hypertension and Treatment Options in the Paediatric Population

Pulmonary hypertension (PH) is a complex condition that can occur as a result of a wide range of disorders, including left heart disease, lung disease, and chronic pulmonary thromboembolism. Multiple improvements have been made in the diagnosis and treatment of pulmonary arterial hypertension (PAH) including a greater understanding of the involvement of extrapulmonary vascular organ systems, validated point of care, clinical assessment tools, and a focus on the initial exposure of numerous pharmacotherapeutics in the appropriate level of care. To achieve a minimal symptom burden, improve the patient's biochemical, hemodynamic, and functional profile, and reduce adverse impact, early diagnosis of PAH is a key objective today. The preferred method of management for thromboembolic PH, which is chronic, is pulmonary endarterectomy since the majority of affected patients are operable. The timing of pulmonary endarterectomy should never be delayed for medical reasons, and risk stratification can enable us to select patients who have a high chance of success. Patients who are not qualified for endarterectomy should be referred for drug trials. Even though there are more effective ways to guarantee a sufficient, long-lasting septostomy, atrial septostomy is promising but undervalued. The procedure's indications remain the same and need to be taken into account more frequently. Class III or IV patients who are not improving need to be consulted at a transplant centre as soon as possible as they may be candidates for potential recipients of bilateral sequential lung or heart-lung transplants, which is a significant choice for some people. PH is rarely linked to other conditions like connective tissue or thromboembolic disease. It is either idiopathic or linked to congenital heart disease. Infants and children with PH are more frequently recognised in conjunction with a congenital diaphragmatic hernia and developmental lung diseases like bronchopulmonary dysplasia. Although the underlying disease has not yet been treated and advanced structural changes have not yet been reversed, the value of natural life and survival have suggestively increased. Children's haemodynamic and functional outcomes have improved as a result of endothelin receptor antagonists, prostacyclin analogues, and phosphodiesterase type 5 inhibitors, which are examples of targeted pulmonary vasodilator therapies. The health maintenance of paediatric PH is still difficult because treatment decisions are largely based on the findings of adult studies that have been supported by evidence and the clinical expertise of paediatric specialists.

Interventionelle Behandlungsverfahren der pulmonalen Hypertension im Kindesalter

Die pulmonale Hypertension (PH) ist eine progressive Gefäßerkrankung und führt über eine Widerstands- und/oder Druckerhöhung im kleinen Kreislauf zu einem fortschreitenden Rechtsherzversagen. Auch wenn mithilfe aktueller medikamentöser Therapien eine deutliche Verbesserung der Lebensqualität und des Überlebens der Betroffenen erreicht werden konnte, bleibt die PH eine zumeist nichtheilbare Erkrankung, die im fortgeschrittenen Stadium eine Lungentransplantation notwendig macht. Interventionelle Verfahren, wie die Anlage eines interatrialen Shunts (z. B. durch atriale Septostomie oder den Atrial Flow Regulator) oder eines Reversed Potts Shunt, verbessern die RV-Funktion und die ventrikuläre Interaktion durch Schaffung einer prä- oder posttrikuspidalen „Eisenmenger-Physiologie“ und stellen eine Überbrückung oder sogar Alternative zur Lungentransplantation dar. Bei Patienten mit segmentaler PH oder chronisch thrombembolischer pulmonaler Hypertension (CTEPH) stellt die Ballonangioplastie eine bereits etablierte Intervention zur Verbesserung der pulmonalen Perfusion und damit rechtsventrikulären (RV-)Funktion dar. Dagegen ist die pulmonalarterielle Denervation ein neuartiges Verfahren, mit dem Ziel, die neurohumorale Dysregulation bei PH positiv zu beeinflussen. Der individuelle Einsatz solcher Interventionen, additiv zu den bereits etablierten medikamentösen Therapien, erweitert die Behandlungsmöglichkeiten und kann die Prognose betroffener Patienten noch weiter verbessern.

Surgical management of giant pulmonary artery aneurysms in patients with severe pulmonary arterial hypertension

BACKGROUND AND AIM

Giant aneurysm of the pulmonary artery (PAA) is an extremely rare condition that may develop in patients with pulmonary arterial hypertension (PAH) which may be complicated by rupture, dissection or intravascular thrombus formation. The aim of this study was to examine available literature with regard to surgical strategies in patients undergoing transplantation for PAH with PAA.

RESULTS

These patients were traditionally considered for heart-lung transplantation but more recently, there have been reports of successful lung transplantation with reconstruction of the pulmonary artery.

CONCLUSIONS

Unless there is a mandatory indication for heart-lung transplantation, patients with PAH and PAA can undergo lung transplantation and reconstruction of the pulmonary artery without compromising the outcome.

Current trends in candidate selection, contraindications, and indications for lung transplantation

Lung transplantation is an established treatment option that can improve quality of life and prolong survival for select patients diagnosed with end-stage lung disease. Given the gaps in organ donation and failures to make effective use of available organs, careful selection of candidates for lung transplant remains one of the most important considerations of the transplant community. Toward this end, we briefly reviewed recent trends in pretransplant evaluation, candidate selection, organ allocation, and organ preservation techniques. Since the latest consensus statement regarding appropriate selection of lung transplant candidates, many advances in the science and practice of lung transplantation have emerged and influenced our perspective of ‘contraindications’ to transplant. These advances have made it increasingly possible to pursue lung transplant in patients with risk factors for decreased survival—namely, older recipient age, increased body mass index, previous chest surgery, poorer nutritional status, and presence of chronic infection, cardiovascular disease, or extrapulmonary comorbid conditions. Therefore, we reviewed the updated evidence demonstrating the prognostic impact of these risk factors in lung transplant recipients. Lastly, we reviewed the salient evidence for current trends in disease-specific indications for lung transplantation, such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, cystic fibrosis, emphysema due to alpha-1 antitrypsin deficiency, and pulmonary arterial hypertension, among other less common end-stage diseases. Overall, lung transplant remains an exciting field with considerable hope for patients as they experience remarkable improvements in quality of life and survival in the modern era.

Oral delivery of ambrisentan-loaded lipid-core nanocapsules as a novel approach for the treatment of pulmonary arterial hypertension

Ambrisentan (AMB) is an orphan drug approved for oral administration that has been developed for the treatment of pulmonary arterial hypertension (PAH), a chronic and progressive pathophysiological state that might result in death if left untreated. Lipid-core nanocapsules (LNCs) are versatile nanoformulations capable of loading lipophilic drugs for topical, vaginal, oral, intravenous, pulmonary, and nasal administration. Our hypothesis was to load AMB into these nanocapsules (LNC_amb) and test their effect on slowing or reducing the progression of monocrotaline-induced PAH in a rat model, upon oral administration. LNC_amb displayed a unimodal distribution of diameters (around 200 nm), negative zeta potential (-11.5 mV), high encapsulation efficiency (78%), spherical shape, and sustained drug release (50-60% in 24 h). The in vivo pharmacodynamic effect of the LNC_amb group was evaluated by observing the echocardiography, hemodynamic, morphometric, and histological data, which showed a significant decrease in PAH in this group, as compared to the control group (AMB_solution). LNC_amb showed the benefit of reversing systolic dysfunction and preventing vascular remodeling with greater efficacy than that observed in the control group. The originality and contribution of our work reveal the promising value of this nanoformulation as a novel therapeutic strategy for PAH treatment.

Right ventricular failure: a comorbidity or a clinical emergency?

There has been ample data providing a convincing perception about the underlying mechanism pertaining to left ventricle (LV) hypertrophy progressing towards LV failure. In comparison, data available on the feedback of right ventricle (RV) due to volume or pressure overload is minimal. Advanced imaging techniques have aided the study of physiology, anatomy, and diseased state of RV. However, the treatment scenario of right ventricular failure (RVF) demands more attention. It is a critical clinical risk in patients with carcinoid syndrome, pulmonary hypertension, atrial septal defect, and several other concomitant diseases. Although the remodeling responses of both ventricles on an increase of end-diastolic pressure are mostly identical, the stressed RV becomes more prone to oxidative stress activating the apoptotic mechanism with diminished angiogenesis. This instigates the advancement of RV towards failure in contrast to LV. Empirical heart failure (HF) therapies have been ineffective in improving the mortality rate and cardiac function in patients, which prompted a difference between the underlying pathophysiology of RVF and LV failure. Treatment strategies should be devised, taking into consideration the anatomical and physiological characteristics of RV. This review would emphasize on the pathophysiology of the RVF and the differences between two ventricles in molecular response to stress. A proper insight into the underlying pathophysiology is required to develop optimized therapeutic management in RV-specific HF.

Advanced Circulatory Support and Lung Transplantation in Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a progressive fatal disease. Although medical therapies have improved the outlook for these patients, there still exists a cohort of patients with PAH who are refractory to these therapies. Lung transplantation (LT), and in certain cases heart-lung transplantation (HLT), is a therapeutic option for patients with severe PAH who are receiving optimal therapy yet declining. ECMO may serve as a bridge to transplant or recovery in appropriate patients. Although, the mortality within the first 3 months after transplant is higher in PAH recipients than the other indications for LT, and the long-term survival after LT is excellent for this group of individuals. In this review, we discuss the indications for LT in PAH patients, when to refer and list patients for LT, the indications for double lung transplant (DLT) versus HLT for PAH patients, types of advanced circulatory support for severe PAH, and short and long-term outcomes in transplant recipients with PAH.

Performance of a 3D convolutional neural network in the detection of hypoperfusion at CT pulmonary angiography in patients with chronic pulmonary embolism: a feasibility study

Background

Chronic pulmonary embolism (CPE) is a life-threatening disease easily misdiagnosed on computed tomography. We investigated a three-dimensional convolutional neural network (CNN) algorithm for detecting hypoperfusion in CPE from computed tomography pulmonary angiography (CTPA).

Methods

Preoperative CTPA of 25 patients with CPE and 25 without pulmonary embolism were selected. We applied a 48%–12%–40% training-validation-testing split (12 positive and 12 negative CTPA volumes for training, 3 positives and 3 negatives for validation, 10 positives and 10 negatives for testing). The median number of axial images per CTPA was 335 (min–max, 111–570). Expert manual segmentations were used as training and testing targets. The CNN output was compared to a method in which a Hounsfield unit (HU) threshold was used to detect hypoperfusion. Receiver operating characteristic area under the curve (AUC) and Matthew correlation coefficient (MCC) were calculated with their 95% confidence interval (CI).

Results

The predicted segmentations of CNN showed AUC 0.87 (95% CI 0.82–0.91), those of HU-threshold method 0.79 (95% CI 0.74–0.84). The optimal global threshold values were CNN output probability ≥ 0.37 and ≤ -850 HU. Using these values, MCC was 0.46 (95% CI 0.29–0.59) for CNN and 0.35 (95% CI 0.18–0.48) for HU-threshold method (average difference in MCC in the bootstrap samples 0.11 (95% CI 0.05–0.16). A high CNN prediction probability was a strong predictor of CPE.

Conclusions

We proposed a deep learning method for detecting hypoperfusion in CPE from CTPA. This model may help evaluating disease extent and supporting treatment planning.

Heart failure therapy based on interventricular mechanics and cardio-vascular communications

The heart should not be divided in right and left, whether in health nor in disease. However, the morphological and functional differences between the right and left ventricle should be known and the impact of the ventricle's position considered. Further, the parameters beyond heart rate, contractility, pre- and afterload guaranteeing a sufficient systemic cardiac output have to be integrated in therapeutic measures; preferentially the influence of interventricular mechanics. Despite of recent developments of specific drug therapies, heart failure is associated with a high rate of morbidity and mortality in children. During the progression of heart failure, pulmonary vascular disease is the consequence or the reason for further failing. Clinical symptoms are associated with congestion and low cardiac output at rest or exercise. Improved understanding of the pathophysiological mechanisms particularly of ventricular failure has resulted in the development of innovative therapies that target atrial/ventricular/arterial interactions. Recent advances in interventional and surgical approaches provide promising new strategies to deal with right and left ventricular deterioration. These techniques may delay listing for heart and (heart-) lung transplantation or even make redundant in individual cases. The beneficial effects of these ventricular interaction strategies are mainly based on the mechanics of the interventricular septum and improvement of systolic and diastolic ventricular performance.

Interventional and Surgical Treatments for Pulmonary Arterial Hypertension

Despite significant advancements in pharmacological treatment, interventional and surgical options are still viable treatments for patients with pulmonary arterial hypertension (PAH), particularly idiopathic PAH. Herein, we review the interventional and surgical treatments for PAH. Atrial septostomy and the Potts shunt can be useful bridging tools for lung transplantation (Ltx), which remains the final surgical treatment among patients who are refractory to any other kind of therapy. Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) remains the ultimate bridging therapy for patients with severe PAH. More importantly, VA-ECMO plays a crucial role during Ltx and provides necessary left ventricular conditioning during the initial postoperative period. Pulmonary denervation may potentially be a new way to ensure better transplant-free survival among patients with the aforementioned disease. However, high-quality randomized controlled trials are needed. As established, obtaining the Eisenmenger physiology among patients with severe pulmonary hypertension by creating artificial defects is associated with improved survival. However, right-to-left shunting may be harmful after Ltx. Closure of the artificially created defects may carry some risk associated with cardiac surgery, especially among patients with Potts shunts. In conclusion, PAH requires an interdisciplinary approach using pharmacological, interventional, and surgical modalities.

Intensive care management of right ventricular failure and pulmonary hypertension crises

Pulmonary hypertension (PH), an often unrelenting disease that carries with it significant morbidity and mortality, affects not only the pulmonary vasculature but, in turn, the right ventricle as well. The survival of patients with PH is closely related to the right ventricular function. Therefore, having an understanding of how to manage right ventricular failure (RVF) and acute pulmonary hypertensive crises is imperative for clinicians who encounter these patients. This review addresses the management of these patients in detail, addressing: (a) the pathophysiology of RVF, (b) intensive care monitoring of these patients in the intensive care unit, (c) imaging of the right ventricle, (d) intubation and mechanical ventilation, (e) inotrope and vasopressor selection, (f) pulmonary vasodilator use, (g) interventional and surgical procedures for the acutely failing right ventricle, and (h) mechanical support for RVF.

Study of the effect of Occlutech Atrial Flow Regulator on symptoms, hemodynamics, and echocardiographic parameters in advanced pulmonary arterial hypertension

Optimal sized balloon atrial septostomy improves hemodynamics in advanced pulmonary arterial hypertension. Occlutech Atrial Flow Regulator is designed to provide an atrial septal fenestration diameter titrated according to the age and right atrial pressures. This observational study analyzed symptoms, exercise distance, oxygen saturations, hemodynamics and echocardiographic parameters after Atrial Flow Regulator implantation in patients with syncope or right-heart failure. Patients with high-risk predictors of mortality during septostomy were scrutinized. Thirty-nine patients (9 children) with syncope (34/39) or right-heart failure (27/39) underwent Atrial Flow Regulator implantation without procedural complications. Six-minute walk distance increased from 310 ± 158.2 to 376.4 ± 182.6 m, none developed syncope. Oxygen saturations reduced from 96.4 ± 6.4% to 92 ± 4.9% at rest and further to 80.3 ± 5.9% on exercise. Right atrial pressures reduced from 9.4 ± 5 (2-27) mmHg to 6.9 ± 2.6 (1-12) mmHg, while cardiac index increased from 2.4 ± 0.8 (0.98-4.3) to 3 ± 1 (1.1-5.3) L/min/m² and systemic oxygen transport increased from 546.1 ± 157.9 (256.2-910.5) to 637.2 ± 191.1 (301.3-1020.2) ml/min. Echocardiographic improvement included significant reduction of pericardial effusion and inferior caval congestion at a median follow-up of 37 months. Overall survival improved except two early and one late deaths in high-risk patients. Five of seven patients with advanced disease and key hemodynamic predictors of mortality survived. Acute hemodynamic benefits in pulmonary arterial hypertension after Atrial Flow Regulator were improved cardiac output, systemic oxygen transport, and reduced right atrial pressures. Improvement of symptoms especially syncope, exercise duration, and right ventricular systolic function as well as device patency were sustained on mid-term follow-up. Implantation was safe in all including young children without procedural complications. Mortality was noted only in patients who had high-risk predictors and patients at advanced stage of the disease.

Focused Update on Pulmonary Hypertension in Children-Selected Topics of Interest for the Adult Cardiologist

Pulmonary hypertensive vascular disease (PHVD), and pulmonary hypertension (PH), which is a broader term, are severe conditions associated with high morbidity and mortality at all ages. Treatment guidelines in childhood are widely adopted from adult data and experience, though big differences may exist regarding aetiology, concomitant conditions and presentation. Over the past few years, paediatric aspects have been incorporated into the common guidelines, which currently address both children and adults with pulmonary hypertension (PH). There are multiple facets of PH in the context of cardiac conditions in childhood. Apart from Eisenmenger syndrome (ES), the broad spectrum of congenital heart disease (CHD) comprises PH in failing Fontan physiology, as well as segmental PH. In this review we provide current data and novel aspects on the pathophysiological background and individual management concepts of these conditions. Moreover, we focus on paediatric left heart failure with PH and its challenging issues, including end stage treatment options, such as mechanical support and paediatric transplantation. PH in the context of rare congenital disorders, such as Scimitar Syndrome and sickle cell disease is discussed. Based on current data, we provide an overview on multiple underlying mechanisms of PH involved in these conditions, and different management strategies in children and adulthood. In addition, we summarize the paediatric aspects and the pros and cons of the recently updated definitions of PH. This review provides deeper insights into some challenging conditions of paediatric PH in order to improve current knowledge and care for children and young adults.

Postpartum Pulmonary Hypertension Masquerading as Submassive Pulmonary Embolism: A Case Report and a Literature Review

Postpartum pulmonary hypertension (PPPHT) is an extremely rare disorder, with few reported cases. Late diagnosis and treatment are associated with significant morbidity and mortality. We present an 18-year-old female patient who presented four-week postpartum with a typical submissive pulmonary embolism picture subsequently diagnosed as postpartum pulmonary hypertension. The patient had an excellent response to treatment, with a dramatic improvement in her functional status. The authors aim to urge physicians to keep this rare disorder in mind as timely and accurate diagnosis is crucial for management—additionally, the importance of counseling patients about the imminent risks associated with planned future pregnancies.

Graded balloon atrial septostomy for palliation of congenital pulmonary hypertension in a dog: A case report

CASE DESCRIPTION

A 6-month-old intact female Maltese dog was presented for acute onset of syncope.

CLINICAL FINDINGS

The dog was presented for collapse upon excitement and exercise. It collapsed at discharge and suffered cardiopulmonary arrest. Echocardiography after resuscitation indicated severe pulmonary hypertension without evidence of intracardiac or extracardiac shunting. A presumptive diagnosis of congenital pulmonary hypertension was made.

TREATMENT AND OUTCOME

Initial treatment with sildenafil was effective at relieving syncope, but the extent of pulmonary hypertension as determined by serial echocardiography was unchanged. Graded balloon atrial septostomy was performed as a palliative procedure. Follow-up echocardiography identified a patent interatrial communication with bidirectional shunting. The dog remained asymptomatic 18 months after treatment.

CLINICAL RELEVANCE

To the best of our knowledge, this study is the first report in the veterinary literature of graded balloon atrial septostomy performed for therapeutic purposes. Further studies are required to determine if this palliative procedure is a beneficial treatment option for dogs with congenital or severe refractory pulmonary hypertension.

Right ventricular dysfunction is associated with the development of chronic thromboembolic pulmonary hypertension but not with mortality post-acute pulmonary embolism

Chronic thromboembolic pulmonary hypertension (CTEPH), a late complication of pulmonary embolism (PE), is associated with high mortality. However, whether the right ventricular (RV) echocardiographic parameters can predict - in the short- and long-term - the development of CTEPH and mortality after PE remains unknown. Herein, we aim to investigate the incidence of CTEPH after acute PE and to evaluate the risk factors of CTEPH. In this retrospective cohort, patients with PE were followed for 10 years for the onset of CTEPH. The screening was initially conducted through echocardiography and confirmed by right heart catheterization. Also, transient and permanent risk factors were identified. Among 358 patients with PE, 8 patients (4%) were subsequently diagnosed with CTEPH at a median time of 36 months and 47 died during the follow-up period. Notably, both short- and long-term RV dilatation, hypertrophy, and increased pulmonary pressure increased the incidence of CTEPH. However, RV echocardiographic parameters failed to differentiate survivors from non-survivors. Instead, malignancy, respiratory, or chronic heart failure was strongly associated with post PE mortality in the multivariable analysis. According to our findings, post PE screening of CTEPH may facilitate early diagnosis and intervention for patients at high risk of developing CTEPH. Also, RV echocardiographic parameters are associated with subsequent CTEPH, but mortality is mainly dependent on underlying comorbidities.

Balloon Pulmonary Angioplasty in Patients With Chronic Thromboembolic Pulmonary Hypertension - A Systematic Review and Meta-Analysis

BACKGROUND

Balloon pulmonary angioplasty (BPA) is a percutaneous treatment option for patients affected by chronic thromboembolic pulmonary hypertension (CTEPH) and either judged inoperable or with persistent symptoms after pulmonary endoarteriectomy. Current data regarding BPA are sparse and results vary according to local center experience. A systematic review of the literature was performed to better understand the effectiveness and safety of BPA in the treatment of CTEPH.Methods and Results:PubMed and EMBASE were searched for studies reporting BPA results in patients with CTEPH. Differences in clinical and hemodynamic parameters before and after the procedure were analyzed. Weighted mean proportion and 95% confidence intervals (CIs) of adverse events were calculated. In total, 14 studies were included (725 patients). BPA was associated with a reduction in mean pulmonary artery pressure (from 43 to 32.5 mmHg), reduction in pulmonary vascular resistance (from 9.94 to 5.06 Woods units), increase in cardiac index (from 2.35 to 2.62 L/min/m²), and improvement of 6-minute walking distance (from 345 to 442 m). Periprocedural mortality occurred in 2.1% of patients (95% CoI 0.8-4.1) while reperfusion and pulmonary vessel injuries occurred in 9.3% (95% CoI 3.1-18.4) and 2.3% (95% CoI 0.9-4.5) of total BPA sessions, respectively.

CONCLUSIONS

Our systematic review suggested that BPA for CTEPH patients was an effective and relatively safe treatment option.

Balloon pulmonary angioplasty vs riociguat in patients with inoperable chronic thromboembolic pulmonary hypertension: A systematic review and meta-analysis

Backgrounds

No previous meta‐analyses have compared the efficacy and safety of BPA with riociguat therapy in inoperable CTEPH patients.

Methods

Relevant published studies were searched in the PubMed, Embase and ClinicalTrial.gov databases.

Results

Twenty‐three clinical trials including 1454 patients (631 underwent BPA; 823 underwent riociguat therapy) were analyzed. BPA was associated with a greater improvement in RAP (mean difference (MD) = −3.53 mmHg, 95% CI: [−4.85, −2.21] vs MD = −1.05 mmHg, 95% CI: [−1.82, −0.29]); mPAP (MD = −15.02 mmHg, 95% CI: [−17.32, −12.71] vs MD = −4.19 mmHg, 95% CI: [−5.58, −2.80]); PVR (standard MD = −1.32 woods, 95% CI: [−1.57, −1.08] vs standard MD = −0.65 woods, 95% CI: [−0.79, −0.50]); NYHA functional class (RR = 6.78, 95% CI: [3.14, 14.64] vs RR = 1.49, 95% CI: [1.07, 2.07]); and 6MWD (MD = 71.66 m, 95% CI: [58.34, 84.99] vs MD = 45.25 m, 95% CI: [36.51, 53.99]) than riociguat treatment. However, the increase in CO was greater with riociguat (MD = 0.78 L/min, 95% CI: [0.61, 0.96]) than with BPA (MD = 0.33 L/min, 95% CI: [0.06, 0.59]). No significant difference in cardiac index (CI) was found between BPA (MD = 0.40 L/min/m², 95% CI: [0.21, 0.58]) and riociguat (MD = 0.40 L/min/m², 95% CI: [0.26, 0.54]). The most common complications of BPA were pulmonary injury (0.3%‐5.6%) and pulmonary edema (0.8%‐28.6%). The most common adverse events of riociguat were headache, dizziness, hypotension and nasopharyngitis.

Conclusions

Our meta‐analysis indicates that BPA might be associated with greater improvements in exercise tolerance and pulmonary hemodynamics except for cardiac output and cardiac index than riociguat therapy. However, both of them were well tolerated.

Principles of pharmacological correction of pulmonary arterial hypertension

Definition and classification: Pulmonary hypertension (PH) is a group of life-threatening progressive diseases of various genesis, characterized by a progressive increase in arterial pressure (AP) in the pulmonary artery (PA), the remodeling of pulmonary vessels, which leads to an increase in pulmonary vascular resistance and pulmonary arterial pressure and more often leads to right ventricular heart failure and premature death. Pulmonary hypertension is clinically divided into five groups: patients in the first group have idiopathic pulmonary arterial hypertension (IPAH), whereas in patients of other groups secondary PH associated with cardiopulmonary or other systemic diseases is observed. The development of secondary LH is caused by congenital heart defects, collagenoses, presence of thrombus in the pulmonary artery, prolonged high pressure in the left atrium, hypoxemia, chronic obstructive pulmonary diseases (COPDs). In case of secondary PH, thrombosis and other changes in the pulmonary veins occur.

Ways of pharmacological correction of pulmonary hypertension: Over the last decade pharmacotherapy of PH has been developing rapidly, and the introduction of modern methods of treatment, especially for primary PAH, has led to positive results. However, despite the progress in treatment, the functional limitations and survival of patients remain unsatisfactory. Currently, there are two levels of treatment for pulmonary hypertension: primary and specific pathogenetic therapies. Primary therapy is aimed at the main cause of PH. It also includes supportive therapy. Pathogenetic therapy includes prostanoids, endothelin receptor antagonists, and phosphodiesterase-5 inhibitors. Tactics of therapy can be established on the basis of either clinical classification, or functional class. Prostanoids are a promising group of drugs for the treatment of pulmonary arterial hypertension (PAH), since they possess not only vasodilating, but also antiplatelet and antiproliferative actions. Therefore, it seems logical to use prostacyclin and its analogs to treat patients with various forms of PAH.

Effect of Patent Foramen Ovale in Patients With Pulmonary Hypertension

Septostomy reduces right ventricular (RV) workload at the expense of hypoxemia in patients with advanced pulmonary hypertension (PH). A patent foramen ovale (PFO) may serve as a "natural" septostomy, but the incidence and impact of a PFO in PH remains uncertain. We prospectively examined echocardiograms in 404 PH patients referred for initial hemodynamic assessment. Patients included had saline bubble injection and if negative repeatinjection after Valsalva maneuver. Echocardiographic and hemodynamic data were examined. Survival was modeled using Kaplan-Meier method. Eisenmenger syndrome or known atrial shunts other than PFO were excluded: 292 patients met entry criteria. A PFO was identified in 16.8% of the entire cohort, 22.9% of pulmonary arterial hypertension (PAH) patients, and 8.6% of Dana Point group 2 PH patients. Right atrial to pulmonary capillary wedge pressure difference was lowest in the latter group (-7.9 ± 7.1 vs -1.7 ± 5.5 mm Hg for all others, p <0.01). Patients with a PFO were younger (53.9 vs 58.6 years, p = 0.02). A PFO was more often present with moderately or severely dilated (p = 0.01) or dysfunctional (p = 0.03) RVs. Six year survival was unchanged by PFO presence for all patients, including those with PAH. Proportional hazards analysis found only age and functional class independently predicted survival (p <0.01). A PFO is identified less often in Dana Point group 2 PH, likely due to inability of Valsalva maneuver to overcome right atrial to pulmonary capillary wedge pressure difference. In conclusion, the incidence of a PFO in the PH population increases with more dilated and dysfunctional RVs, suggesting that the PFO may be stretched open rather than congenital. The presence of a PFO does not impact survival in PH or PAH.

CONTEMPORARY STRATEGY OF PULMONARY HYPERTENSION MANAGEMENT IN PEDIATRICS

Pulmonary hypertension (PH) in pediatrics is a polygenic multifactorial condition with extremely adverse prognosis. Selection of optimal management is a severe task. In absence of treatment the mean life duration in children is not higher one year. Last two decades, revolution in approaches to treatment improved the survival of this patients group. Recently, pediatricians and pediatric cardiologists have three drugs groups that act on the main pathogenetic chains of PH: endothelin pathway, nitric oxide pathway and prostacyclin pathway. At the moment, approaches to pediatric PH are based on the data obtained in the trials on adult patients. However, not long ago there were first randomized trials on children performed. The group of authors of current article presents a modern view on the problem of PH in children, and expert recommendations on children management. Class of recommendations and evidence level were set by the data obtained in pediatric population or on adult population with at least 10% of children included. To the strategy, developed by the Russian clinicians, laid the analysis of experience of the pathology treatment in Russian Federation, as the current practics and clinical guidelines on pediatric PH in Europe, and the recent trials published.

Advanced pulmonary arterial hypertension: mechanical support and lung transplantation

The development of targeted therapies has transformed the outlook for patients with pulmonary arterial hypertension (PAH); however, some patients fail to achieve an adequate clinical response despite receiving maximal treatment. For these patients, lung transplantation remains an important therapeutic option, and recommendations for transplantation are included in the current European Society of Cardiology/European Respiratory Society guidelines for the diagnosis and treatment of pulmonary hypertension. Although lung transplantation is not without risk, overall long-term survival rates are good and substantial improvements in quality of life have been reported for lung transplant recipients. In this review, we describe the important considerations prior to, during and after transplantation, including the role of mechanical support, in patients with advanced PAH.

Lung transplantation and mechanical support play key therapeutic roles in patients with advanced PAHhttp://ow.ly/mqfG30gMcMd

Treatment and Prognosis of Pulmonary Hypertension in the Left Ventricular Assist Device Patient

This review will discuss the medical management of pulmonary hypertension in patients with left ventricular assist devices. Although much has been written on the management of primary pulmonary hypertension, also called pulmonary arterial hypertension, this review will instead focus on the treatment of pulmonary hypertension secondary to left heart disease. The relevant pharmacotherapy can be divided into medications for treating heart failure, such as diuretics and β-blockers, and medications for treating pulmonary hypertension. We also discuss important preoperative considerations in patients with pulmonary hypertension; the relationships between left ventricular assist devices, pulmonary hemodynamics, and right heart failure; as well as optimal perioperative and long-term postoperative medical management of pulmonary hypertension.

Current Trends and Future Perspectives in the Treatment of Pulmonary Arterial Hypertension

Pulmonary hypertension continues to be a life-threatening illness with debilitating physical and emotional consequences affecting around 1% of global population. The progression of this devastating disease is characterized by increase in pulmonary vascular resistance resulting in elevated pulmonary pressure, eventually leading to right heart failure and death. Better understanding of pathophysiology has led to substantial improvements in terms of availability of treatment options. The purpose of this review is to summarize the currently available treatment options along with pertinent trials and possible future therapies of pulmonary arterial hypertension.

Low-flow support of the chronic pressure-overloaded right ventricle induces reversed remodeling

BACKGROUND

Mechanical right ventricular (RV) support in pulmonary arterial hypertension patients has been feared to cause pulmonary hemorrhage and to be detrimental for the after-load-sensitive RV. Continuous low-flow pumps offer promise but remain insufficiently tested.

METHODS

The pulmonary artery was banded in 20 sheep in this study. Eight weeks later, a Synergy micro-pump (HeartWare International, Framingham MA) was inserted in 10 animals, driving blood from the right atrium to the pulmonary artery. After magnetic resonance imaging, hemodynamics and RV pressure-volume loop data were recorded. Eight weeks later, RV function was assessed in the same way, followed by histologic analysis of the ventricular tissue.

RESULTS

During the 8 weeks of support, RV volumes and central venous pressure decreased significantly, whereas RV contractility increased. Pulmonary artery pressure increased modestly, particularly its diastolic component. RV contribution to total right-sided cardiac output increased from 12 ± 12% to 41 ± 9% (p < 1 × 10^-4). After pump inactivation, and compared with 8 weeks earlier, RV volumes had significantly decreased, tricuspid valve regurgitation had almost disappeared, and RV contractility had significantly increased, resulting in significantly increased RV forward power (0.25 ± 0.05 vs 0.16 ± 0.06 W, p = 0.014). Fulton index and RV myocyte size were significantly smaller, and without changes in fibrosis, when compared with controls.

CONCLUSIONS

Prolonged continuous low-flow RV mechanical support significantly unloads the chronic pressure-overloaded RV and improves cardiac output. After 8 weeks, RV hemodynamic recovery and reverse remodeling begin to occur, without increased fibrosis.

Pulmonary Vascular Diseases in the Elderly

Pulmonary hypertension is a pathologic hemodynamic condition defined by a mean pulmonary arterial pressure of 25 mm Hg or greater at rest. Because of age-associated stiffening of the heart and the pulmonary vasculature and the higher prevalence in the elderly of comorbidities associated with the development of pulmonary hypertension, it is an increasingly common finding in this patient population. A right heart catheterization is necessary for the diagnosis and characterization of pulmonary hypertension. The general management is to treat the underlying conditions responsible for the development of the disorder. Pulmonary vasodilators are indicated in patients with pulmonary arterial hypertension.

High Frequency of Acute Adverse Cardiovascular Events After Lung Transplantation in Patients With Pulmonary Arterial Hypertension Receiving Preoperative Long-Term Intravenous Prostacyclin

Adverse cardiovascular events after lung transplantation (LT) increase the mortality in patients with pulmonary arterial hypertension (PAH). Long-term intravenous prostacyclin is the usual treatment in severe patients with PAH, but it may increase the risk of hemorrhage due to its antiplatelet aggregation effect or thrombocytopenia. We investigated the impact of length of intravenous prostacyclin therapy on acute adverse cardiovascular events including hemorrhagic complication after LT. We retrospectively compared the incidence of adverse events (death, intrathoracic hematoma and bleeding, cardiac congestion or shock, cerebral infarction and pulmonary embolism) within 30 days after LT between no/short-term (median 0.6 years, n = 13) and long-term (median 3.7 years, n = 15) intravenous prostacyclin groups. There were no differences in the dose of intravenous prostacyclin and pulmonary artery pressure between the two groups. Among 22 adverse events (0.8 ± 1.1 events/patient), 4 events occurred in the no/short-term intravenous prostacyclin group and 18 occurred in the long-term intravenous prostacyclin group. The event rate per patient in the long-term intravenous prostacyclin group (1.2 ± 1.3 events/patient) was significantly higher than that in the no/short-term intravenous prostacyclin group (0.3 ± 0.5 events/patient) (P < 0.05). Intrathoracic hematoma and bleeding was the most frequent adverse event (9 events, 41%). Preoperative long-term intravenous prostacyclin therapy increases acute adverse cardiovascular events after LT in patients with PAH.

Pulmonary hypertension: diagnosis, imaging techniques, and novel therapies

Pulmonary hypertension (PH), defined as the elevation of mean pulmonary arterial pressure (mPAP) above 25 mmHg, has numerous causes, which the World Health Organization (WHO) has divided into five distinct categories based upon the underlying mechanism of action. This review will explore the pathophysiology, diagnostic testing, and treatment of PH. Identification of PH depends on a strong clinical suspicion, a detailed history, and a thorough physical exam. We review the evidence supporting experimental and clinical laboratory parameters for diagnosis and monitoring of PH. Transthoracic echocardiogram (TTE) is the initial screening test of choice. This review will detail specific echocardiographic techniques for the assessment and classification of PH. Furthermore, the importance of advanced imaging, including computed tomography (CT) and magnetic resonance imagining (MRI) is explored. New developments in pharmacology, percutaneous intervention, and surgical approaches are summarized. Finally, we will address the tools available to predict morbidity and mortality.

Interatrial shunt devices for heart failure with normal ejection fraction: a technology update

Heart failure with normal ejection fraction (HeFNEF) accounts for ~50% of heart failure admissions. Its pathophysiology and diagnostic criteria are yet to be defined clearly which may hinder the search for effective treatments. The clinical hallmark of HeFNEF is exertional breathlessness, often due to an abnormal increase in left atrial pressure during exercise. Creation of an interatrial communication to offload the left atrium is a possible therapeutic approach. There are two percutaneously delivered devices currently under investigation which are discussed in this review.

The dilatation of main pulmonary artery and right ventricle observed by enhanced chest computed tomography predict poor outcome in inoperable chronic thromboembolic pulmonary hypertension

BACKGROUND

Dilatation of the pulmonary artery and right ventricle on chest computed tomography images is often observed in patients with pulmonary hypertension. The clinical significance of these image findings has not been defined in chronic thromboembolic pulmonary hypertension. We investigated whether the pulmonary arterial and right ventricle dilatation was associated with poor outcome in chronic thromboembolic pulmonary hypertension.

METHODS

This was a retrospective cohort investigation in 60 subjects with inoperable chronic thromboembolic pulmonary hypertension diagnosed consecutively between 1997 and 2010 at Chiba University Hospital. Digital scout multi-detector chest computed tomography images were obtained. The main pulmonary arterial to ascending aortic diameter ratio and the right ventricular to left ventricular diameter ratio were calculated.

RESULTS

Main pulmonary arterial to ascending aortic diameter ratio ranged from 0.85 to 1.84, and right ventricular to left ventricular diameter ratio ranged from 0.71 to 2.88. During the observation period of 1284.5days (range, 21-4550days), 13 patients required hospitalization due to worsening; 6 of them died. Kaplan-Meier analysis showed significant differences in hospitalization between the patients with main pulmonary arterial to ascending aortic diameter ratio of ≥1.1 and <1.1 (log-rank test, p=0.014) and between the patients with right ventricular to left ventricular diameter ratio of ≥1.2 and <1.2 (log-rank test, p=0.013). There was a significant difference in the prognosis between the patients with RV/LV ratio≥1.2 and those with RV/LV ratio<1.2 (log-rank test, p=0.033).

CONCLUSIONS

Main pulmonary arterial to ascending aortic diameter ratio measured using enhanced CT images was associated with the risk for first clinical exacerbation, and right ventricular to left ventricular diameter ratio was associated with the risk for poor prognosis in inoperable chronic thromboembolic pulmonary hypertension.

An epidemiological analysis of the burden of chronic thromboembolic pulmonary hypertension in the USA, Europe and Japan

Epidemiological data for chronic thromboembolic pulmonary hypertension (CTEPH) are limited and there are conflicting reports regarding its pathogenesis.

A literature review was conducted to identify CTEPH epidemiological data up to June 2014. Data were analysed to provide estimates of the incidence of CTEPH in the USA, Europe and Japan. An epidemiological projection model derived country-specific estimates of future incidence and diagnosis rates of CTEPH.

Overall, 25 publications and 14 databases provided quantitative epidemiological data. In the USA and Europe, the crude annual incidence of diagnosed pulmonary embolism and crude annual full (i.e. diagnosed and undiagnosed) incidence of CTEPH were 66–104 and 3–5 cases per 100 000 population, respectively, while in Japan these rates were lower at 6.7 and 1.9 per 100 000 population, respectively. In 2013, 7–29% of CTEPH cases in Europe and the USA were diagnosed, and the majority of patients were in New York Heart Association functional class III/IV at diagnosis. The projection model indicated that incidence of CTEPH will continue to increase over the next decade.

These data suggest that CTEPH is underdiagnosed and undertreated, and there is an urgent need to increase awareness of CTEPH. High-quality epidemiological studies are required to increase understanding of CTEPH.

Epidemiological data suggest that CTEPH is underdiagnosed and there is an urgent need to improve disease awarenesshttp://ow.ly/J0KC3095U2W

Comparison of the efficacy of four endobronchial ablation techniques in dogs

The present study aimed to evaluate the safety and efficacy of four commonly used ablation techniques, namely neodymium-doped yttrium aluminium garnet (Nd:YAG) laser therapy, argon plasma coagulation (APC), high-frequency electrocautery and CO₂ cryotherapy. The techniques were performed at various powers or impedance settings, and for various durations, on the trachea of beagle dogs. Pathological changes of the tracheal wall were assessed by bronchoscopy. The endoscopic gross appearance of lesions induced by ablation treatments was consistent with the histopathological changes. The results suggested that cryotherapy was relatively safe, whereas APC induced superficial tissue coagulative necrosis. Furthermore, Nd:YAG laser therapy was the most efficient technique and showed the greatest penetration potential. In general, tissue injury was exacerbated with extended application time, at constant power or impedance. The safest application parameters were 20 W for ≤1 sec for Nd:YAG laser therapy, 40 W for ≤3 sec for electrocautery, 40 W for ≤5 sec for APC and 100 Ω for ≤120 sec for cryotherapy. At the maximum times, these settings resulted in identical pathological changes. Healing of the lesions following ablation was achieved within 3 weeks. The Nd:YAG laser, APC, electrocautery and cryotherapy endobronchial ablation techniques differed according to their potential and limitations for application on the trachea. However, when applied at specific combinations of power or impedance and duration, they exhibited similar efficacies.

An Update on the Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but life-threatening form of pulmonary artery hypertension that is defined as a mean arterial pulmonary pressure greater than 25mmHg that persists for more than 6 months following anticoagulation therapy in the setting of pulmonary emboli. CTEPH is categorized by the World Health Organization as group IV pulmonary hypertension and is thought to be due to unresolved thromboemboli in the pulmonary artery circulation. Among the 5 classes of pulmonary hypertension, CTEPH is unique in that it is potentially curable with the use of pulmonary thromboendarterectomy surgery. Despite an increasing array of medical and surgical treatment options for patients with CTEPH over the past 2 decades, patients commonly present with advanced disease and carry a poor prognosis, thus, the need for early diagnosis and appropriate referral to an expert center. This review article first highlights the epidemiology, pathophysiology, and clinical presentation of CTEPH. The article then provides diagnostic and therapeutic algorithms for the management of the patient with suspected CTEPH.

The Anesthetic Challenges of Lung Biopsy-Associated Intrathoracic Hemorrhage in a Child With Suprasystemic Pulmonary Hypertension

Children with suspected pulmonary hypertension must undergo extensive and invasive evaluations to establish a definitive diagnosis. A previously healthy 4-year old girl, newly diagnosed with suprasystemic pulmonary hypertension required multiple lung biopsies. Each procedure was associated with significant bleeding. The challenging anesthetic management of lung biopsy in the presence of suprasystemic pulmonary hypertension is described.

Treatment of children with pulmonary hypertension. Expert consensus statement on the diagnosis and treatment of paediatric pulmonary hypertension. The European Paediatric Pulmonary Vascular Disease Network, endorsed by ISHLT and DGPK

Treatment of children and adults with pulmonary hypertension (PH) with or without cardiac dysfunction has improved in the last two decades. The so-called pulmonary arterial hypertension (PAH)-specific medications currently approved for therapy of adults with PAH target three major pathways (endothelin, nitric oxide, prostacyclin). Moreover, some PH centres may use off-label drugs for compassionate use. Pulmonary hypertensive vascular disease (PHVD) in children is complex, and selection of appropriate therapies remains difficult. In addition, paediatric PAH/PHVD therapy is vastly based on experience and trial data from adult rather than paediatric studies; however, the first randomised paediatric PAH trials have been conducted recently. We present consensus recommendations for the treatment of children with PH. Class of recommendation and level of evidence were assigned based on paediatric data only or on adult studies that included >10% children. After a systematic literature search and analysis of the published data, we developed treatment strategies and algorithms that can guide goal-oriented PH therapy. We discuss early combination therapy (double, triple) in patients with PAH in functional class II-IV and in those with inadequate response to the initial pharmacotherapy. In those children with progressive, severe PAH and inadequate response, advances in drug development, and interventional and surgical approaches provide promising new strategies to avoid, reverse or ameliorate right heart failure and left ventricular compression. In particular, first follow-up data indicate that Potts shunt (left pulmonary artery to descending aorta anastomosis) may be an alternative destination therapy, or bridge to bilateral lung transplantation, in end-stage paediatric PAH.

Guanylate cyclase stimulators for pulmonary hypertension

BACKGROUND

Pulmonary hypertension is a condition of complex aetiology that culminates in right heart failure and early death. Soluble guanylate cyclase (sGC) stimulators are a promising class of agents that have recently gained approval for use.

OBJECTIVES

To evaluate the efficacy of sGC stimulators in pulmonary hypertension.

SEARCH METHODS

We searched CENTRAL (Cochrane Central Register of Controlled Trials), MEDLINE, EMBASE and the reference lists of articles. Searches are current as of 12 February 2016.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) involving participants with pulmonary hypertension of all ages, severities and durations of treatment.

DATA COLLECTION AND ANALYSIS

AW, MS and RW independently selected studies, assessed evidence quality and extracted data. This process was overseen by RT and SG. All included studies were sponsored by the drug manufacturer.

MAIN RESULTS

Five trials involving 962 participants are included in this review. All trials were of relatively short duration (< 16 weeks). Due to the heterogenous aetiology of pulmonary hypertension in participants, results are best considered according to each pulmonary hypertension subtype.Pooled analysis shows a mean difference (MD) increase in six-minute walking distance (6MWD) of 30.13 metres (95% CI 5.29 to 54.96; participants = 659; studies = 3). On subgroup analysis, for pulmonary arterial hypertension (PAH) there was no effect noted (6MWD; MD 11.91 metres, 95% CI -44.92 to 68.75; participants = 398; studies = 2), and in chronic thromboembolic pulmonary hypertension (CTEPH) sGC stimulators improved 6MWD by an MD of 45 metres (95% CI 23.87 to 66.13; participants = 261; studies = 1). Data for left heart disease-associated PH was not available for pooling. Importantly, when participants receiving phosphodiesterase inhibitors were excluded, sGC stimulators increased 6MWD by a MD of 36 metres in PAH. The second primary outcome, mortality, showed no change on pooled analysis against placebo (Peto odds ratio (OR) 0.57, 95% CI 0.18 to 1.80).Pooled secondary outcomes include an increase in World Health Organization (WHO) functional class (OR 1.53, 95% CI 0.87 to 2.72; participants = 858; studies = 4), no effect on clinical worsening (OR 0.45, 95% CI 0.17 to 1.14; participants = 842; studies = 3), and a reduction in mean pulmonary artery pressure (MD -2.77 mmHg, 95% CI -4.96 to -0.58; participants = 744; studies = 5). There was no significant difference in serious adverse events on pooled analysis (OR 1.12, 95% CI 0.66 to 1.90; participants = 818; studies = 5) or when analysed at PAH (MD -3.50, 95% CI -5.54 to -1.46; participants = 344; studies = 1), left heart disease associated subgroups (OR 1.56, 95% CI 0.78 to 3.13; participants = 159; studies = 2) or CTEPH subgroups (OR 1.29, 95% CI 0.65 to 2.56; participants = 261; studies = 1).It is important to consider the results for PAH in the context of a person who is not also receiving a phosphodiesterase-V inhibitor, a contra-indication to sGC stimulator use. It should also be noted that CTEPH results are applicable to inoperable or recurrent CTEPH only.Evidence was rated according to the GRADE scoring system. One outcome was considered high quality, two were moderate, and eight were of low or very low quality, meaning that for many of the outcomes the true effect could differ substantially from our estimate. There were only minor concerns regarding the risk of bias in these trials, all being RCTs largely following the original protocol. Most trials employed an intention-to-treat analysis.

AUTHORS' CONCLUSIONS

sGC stimulators improve pulmonary artery pressures in people with PAH (who are treatment naive or receiving a prostanoid or endothelin antagonist) or those with recurrent or inoperable CTEPH. In these settings this can be achieved without notable complication. However, sGC stimulators should not be taken by people also receiving phosphodiestase-V inhibitors or nitrates due to the risks of hypotension, and there is currently no evidence supporting their use in pulmonary hypertension associated with left heart disease. There is no evidence supporting their use in children. These conclusions are based on data with limitations, including unavailable data from two of the trials.