Significance of echocardiographic assessment for right ventricular function after balloon pulmonary angioplasty in patients with chronic thromboembolic induced pulmonary hypertension

Status and Future Directions for Balloon Pulmonary Angioplasty in Chronic Thromboembolic Pulmonary Disease With and Without Pulmonary Hypertension: A Scientific Statement From the American Heart Association

Balloon pulmonary angioplasty continues to gain traction as a treatment option for patients with chronic thromboembolic pulmonary disease with and without pulmonary hypertension. Recent European Society of Cardiology guidelines on pulmonary hypertension now give balloon pulmonary angioplasty a Class 1 recommendation for inoperable and residual chronic thromboembolic pulmonary hypertension. Not surprisingly, chronic thromboembolic pulmonary hypertension centers are rapidly initiating balloon pulmonary angioplasty programs. However, we need a comprehensive, expert consensus document outlining critical concepts, including identifying necessary personnel and expertise, criteria for patient selection, and a standardized approach to preprocedural planning and establishing criteria for evaluating procedural efficacy and safety. Given this lack of standards, the balloon pulmonary angioplasty skill set is learned through peer-to-peer contact and training. This document is a state-of-the-art, comprehensive statement from key thought leaders to address this gap in the current clinical practice of balloon pulmonary angioplasty. We summarize the current status of the procedure and provide a consensus opinion on the role of balloon pulmonary angioplasty in the overall care of patients with chronic thromboembolic pulmonary disease with and without pulmonary hypertension. We also identify knowledge gaps, provide guidance for new centers interested in initiating balloon pulmonary angioplasty programs, and highlight future directions and research needs for this emerging therapy.

Optimal short-term outcomes in balloon pulmonary angioplasty: the minimum frequency of three sessions annually

BACKGROUND

Balloon pulmonary angioplasty (BPA) is typically performed in a sequential manner.

OBJECTIVES

This study aimed to determine the lowest frequency of BPA for patients who could not reach treatment goals in a short period.

DESIGN

Retrospective cohort.

METHODS

We retrospectively enrolled 186 BPA-treated patients diagnosed with chronic thromboembolic pulmonary hypertension. According to the accumulative number of performed BPA sessions or treated pulmonary vessels or the ratio of the number of treated pulmonary vessels/the number of baseline lesions (T/P) prior to the initial occurrence of clinical outcome or censored date, we divided patients into different groups. The principal outcome was clinical worsening.

RESULTS

After stratifying patients by the number of performed BPA sessions, most baseline parameters were comparable among groups. During follow-up, 31 (16.7%) of 186 patients experienced clinical worsening. The 6-month cumulative clinical worsening-free survival rates of ⩾2 performed sessions group were significantly higher than that of 1 performed session group. The 12-month cumulative rates of clinical worsening-free survival exhibited a declining pattern in the subsequent sequence: ⩾3, 2, and 1 performed BPA sessions, and this trend persisted when follow-up time exceeded 12 months. The 6-, 12-, and 24-month cumulative clinical worsening-free survival rates were comparable between patients with 3 and ⩾4 performed BPA sessions. Similar results were also observed when stratifying patients by the accumulative number of treated pulmonary vessels (⩽8, 9-16, ⩾17) and T/P (⩽0.789, 0.790-1.263, ⩾1.264).

CONCLUSION

To achieve optimal short-term outcomes, patients might need to undergo ⩾2 BPA sessions or have ⩾9 pulmonary vessels treated or have T/P ⩾0.790 within 6 months, and undergo ⩾3 BPA sessions or have ⩾17 pulmonary vessels treated or have T/P ⩾1.264 within 12 months.

Monographic Issue on Pulmonary Hypertension: Medical and Interventional Treatment for Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication of acute pulmonary embolism. The reasons why clots do not resorb are incompletely understood, but the result is partial or complete fibrothrombotic obstruction of pulmonary arteries. A secondary microvasculopathy aggravates the pulmonary hypertension (PH) as a consequence of high flow and shear stress in the nonoccluded arteries. The treatment of CTEPH has long been purely surgical, but many patients were inoperable because of inaccessible lesions or severe comorbidities. Alternatives were developed, including medical therapy and more recently balloon pulmonary angioplasty (BPA). Depending on the generation of the obstructed vessels, the treatment will be surgical, up to the (sub)segmental level, or by BPA for more distal vessels. PH drugs are used to treat the microvasculopathy. The current paper describes the therapeutic management of inoperable patients: the medical approach with PH drugs used in mono- or combination therapy; the proper use of anticoagulants in CTEPH; the technique, indications, and results at short- and long-term of BPA; the multimodal approach for inoperable patients combining PH drugs and BPA; and the effects of rehabilitation. It shows the importance of a multidisciplinary approach to the disease.

Impact of Balloon Pulmonary Angioplasty on Right Ventricular Function in Patients With Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) can develop in some patients after an acute pulmonary embolism. The disease is characterized by the conversion of emboli into fibrotic thrombi that chronically impede normal circulation through the pulmonary arteries and increase pulmonary vascular resistance. Over time, this increases right ventricular (RV) afterload and strains the RV. The RV compensates by undergoing cardiomyocyte hypertrophy and RV dilation that can maintain stroke volume. However, these adaptations eventually decrease cardiac output and lead to right heart failure. Balloon pulmonary angioplasty has been developed as a treatment option for CTEPH by systematically disrupting thrombosed vessels and improving blood flow throughout the pulmonary circulation. This ultimately reverses the structural maladaptation's seen in CTEPH and improves RV function.

Evolving Role and Clinical Evidence in the Global Practice of Balloon Pulmonary Angioplasty

Balloon pulmonary angioplasty (BPA) was first described in 2001 and now has evolved into a class I indication for inoperable or residual chronic thromboembolic pulmonary hypertension. This review article aims to describe evidence from studies performed at various pulmonary hypertension (PH) centers across the globe, to better understand the role of BPA in chronic thromboembolic pulmonary disease with and without PH. Additionally, we hope to highlight innovations and the ever-changing safety and efficacy profile of BPA.

Update on the roles of imaging in the management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH), classified as group 4 pulmonary hypertension (PH), is caused by stenosis and obstruction of the pulmonary arteries by organized thrombi that are incompletely resolved after acute pulmonary embolism. The prognosis of patients with CTEPH is poor if untreated; however, in expert centers with multidisciplinary teams, a treatment strategy for CTEPH has been established, dramatically improving its prognosis. CTEPH is currently not a fatal disease and is the only curable form of PH. Despite these advances and the establishment of treatment approaches, early diagnosis is still challenging, especially for non-experts, for several reasons. One of the reasons for this is insufficient knowledge of the various diagnostic imaging modalities, which are essential in the clinical practice of CTEPH. Imaging modalities should detect the following pathological findings: lung perfusion defects, thromboembolic lesions in pulmonary arteries, and right ventricular remodeling and dysfunction. Perfusion lung scintigraphy and catheter angiography have long been considered gold standards for the detection of perfusion defects and assessment of vascular lesions, respectively. However, advances in imaging technology of computed tomography and magnetic resonance imaging have enabled the non-invasive detection of these abnormal findings in a single examination. Cardiac magnetic resonance (CMR) is the gold standard for evaluating the morphology and function of the right heart; however, state-of-the-art techniques in CMR allow the assessment of cardiac tissue characterization and hemodynamics in the pulmonary arteries. Comprehensive knowledge of the role of imaging in CTEPH enables appropriate use of imaging modalities and accurate image interpretation, resulting in early diagnosis, determination of treatment strategies, and appropriate evaluation of treatment efficacy. This review summarizes the current roles of imaging in the clinical practice for CTEPH, demonstrating the characteristic findings observed in each modality.

De-escalation of oxygen-therapy and medication in patients with chronic thromboembolic pulmonary hypertension after balloon pulmonary angioplasty

INTRODUCTION

There is no consensus on the adjustment of home oxygen therapy (HOT) and pulmonary hypertension (PH)-specific medications after balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to examine the status of de-escalation/discontinuation of HOT and PH-specific medications post-BPA and clarify its effect on hemodynamics, biomarkers, and long-term outcomes.

METHODS AND RESULTS

From November 2012 to May 2018, 135 consecutive CTEPH patients who underwent BPA at a single university hospital were enrolled (age, 63.5 ± 13.5 years; World Health Organization functional class [WHO-FC] II/III/IV, 34/92/9). The mean pulmonary arterial pressure decreased from 37.7 ± 11.3 to 20.4 ± 5.1 mmHg 1-year post-BPA (p<0.01). The proportion of patients who required HOT and combination medical therapy (≥2 PH-specific medications) decreased 1-year post-BPA (from 58.5% to 7.4% and from 40.0% to 10.4%, respectively). Baseline factors influencing the requirement of HOT and combination medical therapy post-BPA were almost identical (i.e., lower exercise capacity and pulmonary diffusion capacity, and worse hemodynamics). Regardless of their discontinuation, the improved hemodynamics, functional capacity (WHO-FC), and biomarkers (B-type natriuretic peptide and high-sensitivity troponin T) were almost maintained, and no adverse 1-year clinical outcomes (all-cause death and PH-related hospitalization) were observed.

CONCLUSIONS

Most CTEPH patients discontinued HOT and PH-specific combination medical therapy post-BPA, which was not associated with the deterioration of hemodynamics, functional capacity, or biomarkers. No long-term adverse outcomes were observed.

Riociguat and the right ventricle in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are progressive diseases that can lead to right heart failure and death. Right ventricular dysfunction, hypertrophy and maladaptive remodelling are consequences of increased right ventricular (RV) afterload in PAH and CTEPH and are indicative of long-term outcomes. Because RV failure is the main cause of morbidity and mortality in PAH and CTEPH, successful treatments should lead to improvements in RV parameters. Riociguat is a soluble guanylate cyclase stimulator approved for the treatment of PAH and inoperable or persistent/recurrent CTEPH after pulmonary endarterectomy. This review examines the current evidence showing the effect of riociguat on the right ventricle, with particular focus on remodelling, function and structural parameters in preclinical models and patients with PAH or CTEPH.

A Comprehensive Assessment of Right Ventricular Function in Chronic Thromboembolic Pulmonary Hypertension

While chronic thromboembolic pulmonary hypertension (CTEPH) results from macroscopic and microscopic obstruction of the pulmonary vascular bed, the function of the right ventricle (RV) and increased RV afterload are the main determinants of its symptoms and prognosis. In this review, we assess RV function in patients diagnosed with CTEPH with a focus on the contributions of RV afterload and dysfunction to the pathogenesis of this disease. We will also discuss changes in RV function and geometry in response to treatment, including medical therapy, pulmonary endarterectomy, and balloon pulmonary angioplasty.

The original and two new derivative versions of the COMPERA 2.0 risk assessment model: useful tools for guiding balloon pulmonary angioplasty

Background

The COMPERA 2.0 4-stratum (4-S) risk score has been demonstrated superior over the 3-stratum (3-S) one in patients with pulmonary arterial hypertension and medically managed patients with chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to determine the prognostic value of the original 4-S and 3-S COMPERA 2.0 risk score and two new derivative versions in CTEPH patients who underwent balloon pulmonary angioplasty (BPA).

Methods

We retrospectively enrolled 175 BPA-treated patients with CTEPH. We assessed the risk stratification before and after each BPA session of CTEPH patients by the original 4-S and 3-S COMPERA 2.0 risk score (by rounding decimal to the nearest integer) and two new proposed derivative versions: the modified version (by rounding decimal to the next integer) and a hybrid version that fuses the original and modified versions. The primary endpoint was clinical worsening events. The secondary outcomes were achieving low-risk profile and mean pulmonary arterial pressure (mPAP) < 30 mmHg at follow-up. We used the Kaplan–Meier curve analysis to assess the survival differences between stratified patients. The comparative model’s performance was evaluated in terms of discrimination by Harrell’s C-index.

Results

All versions of COMPERA 2.0 4-S model outperformed the 3-S one in discriminating the differences in echocardiographic and hemodynamic parameters and clinical worsening-free survival rates. The original and hybrid 4-S model could independently predict the primary and secondary endpoints, and the hybrid version seemed to perform better. The first BPA session could significantly improve risk profiles, and these changes were associated with the likelihood of experiencing clinical worsening events, achieving a low-risk profile and mPAP < 30 mmHg at follow-up. The number of BPA sessions required to achieve low risk/mPAP < 30 mmHg increased as the baseline risk score escalated.

Conclusions

The COMPERA 2.0 4-S model outperformed the 3-S one in BPA-treated patients with CTEPH. The 4-S model, especially its hybrid version, could be used to predict clinical outcome before the initiation of BPA and monitor treatment response.

Temporal trends in right heart strain in patients undergoing pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension

BACKGROUND

Pulmonary thromboendarterectomy (PTE) is a curative procedure for chronic thromboembolic pulmonary hypertension (CTEPH). Right ventricular free wall strain (RV FWS) and right atrial strain (RAS) are not well studied in a CTEPH population. We sought to determine temporal trends in RAS and RV FWS in patients post-PTE.

METHODS

28 patients undergoing PTE for CTEPH were prospectively enrolled in a surgical database. Comprehensive echocardiographic assessment of the right heart was performed including RV FWS, right atrial volume, and the three components of RAS: reservoir, conduit, and booster strain.

RESULTS

Patients undergoing PTE demonstrated improvement in NYHA functional class (P < 0.001). Hemodynamic assessment showed improvement in mean pulmonary artery pressure from 49.7 ± 8.5 mm Hg to 23.9 ± 6.5 mm Hg (P < 0.001) and pulmonary vascular resistance decreased from 7.8 ± 3.2 wu to 2.4 ± 1.3 wu (P < 0.001). Tricuspid annular plane systolic excursion (TAPSE) and lateral S` declined immediately post-op. RV FWS improved from -14.4 ± 4% to -19 ± 3.4% post-op and -21.2 ± 4.7% at long-term follow-up (P < 0.001). Improvement in RV FWS post-op was driven primarily by increases in the apical and mid segments. RA volume declined significantly during the study period. RA reservoir and conduit strain improved after PTE.

CONCLUSION

Patients undergoing PTE for CTEPH had significant improvement in right heart hemodynamics immediately post-op. Traditional echo metrics of RV performance including TAPSE and lateral S` did not improve. RV FWS improved, which was driven by changes in the apical and mid segments. This highlights that RV FWS is a viable and useful metric to follow in CTEPH patients post-PTE.

Clinical Significance of Right Ventricular Function in Pulmonary Hypertension

Pulmonary hypertension (PH) is a progressive disease characterized by increased pulmonary vascular resistance that leads to right ventricular (RV) failure, a condition that determines its prognosis. This review focuses on the clinical value of the evaluation of RV function in PH. First, the pathophysiology of PH, including hemodynamics, RV function, and their interaction (known as ventriculoarterial coupling), are summarized. Next, non-invasive imaging modalities and the parameters of RV function, mainly assessed by echocardiography, are reviewed. Finally, the clinical impacts of RV function in PH are described. This review will compare the techniques that yield comprehensive information on RV function and their roles in the assessment of PH.

Evaluation and management of patients with chronic thromboembolic pulmonary hypertension - consensus statement from the ISHLT

ISHLT members have recognized the importance of a consensus statement on the evaluation and management of patients with chronic thromboembolic pulmonary hypertension. The creation of this document required multiple steps, including the engagement of the ISHLT councils, approval by the Standards and Guidelines Committee, identification and selection of experts in the field, and the development of 6 working groups. Each working group provided a separate section based on an extensive literature search. These sections were then coalesced into a single document that was circulated to all members of the working groups. Key points were summarized at the end of each section. Due to the limited number of comparative trials in this field, the document was written as a literature review with expert opinion rather than based on level of evidence.

Clinical Significance of Guanylate Cyclase Stimulator, Riociguat, on Right Ventricular Functional Improvement in Patients with Pulmonary Hypertension

BACKGROUND

Riociguat is a soluble guanylate cyclase stimulator that improves hemodynamics in patients with pulmonary hypertension (PH). Accumulating evidence implicates the additional effect of riociguat on the increase in cardiac output. However, its mechanisms have not been fully understood. This study aimed to investigate whether riociguat could ameliorate right ventricular (RV) contraction as well as hemodynamics.

METHODS

We studied 45 patients with pulmonary arterial hypertension (14) or chronic thromboembolic pulmonary hypertension (31) and evaluated hemodynamics, using right-sided heart catheterization, before and after the administration of riociguat. RV function was assessed by echocardiography, including speckle-tracking echocardiography.

RESULTS

Riociguat significantly improved the WHO functional class and reduced the mean pulmonary arterial pressure and vascular resistance. In addition, the cardiac index increased. RV remodeling was ameliorated after riociguat administration as assessed by the echocardiographic parameters, such as RV diameter and RV area index. RV function, including RV fractional area change and RV global longitudinal strain, also significantly improved, and their improvement was even observed in patients with mild PH after pulmonary endarterectomy or balloon pulmonary angioplasty. Furthermore, covariance analysis revealed that RV global longitudinal strain and RV fractional area change improved after riociguat administration, even with the same mean pulmonary arterial pressure, implicating the improvement of RV contractile function by riociguat, regardless of RV loading.

CONCLUSIONS

Riociguat not only improved the hemodynamics of patients with PH but also ameliorated the echocardiographic parameters with RV function. RV strain could detect the subtle improvement in mild PH, and riociguat may have a benefit even after intervention, as assessed by speckle-tracking echocardiography.

Balloon pulmonary angioplasty reverse right ventricular remodelling and dysfunction in patients with inoperable chronic thromboembolic pulmonary hypertension: a systematic review and meta-analysis

OBJECTIVES

Right ventricular (RV) function is considered the major determinant of prognosis in patients with chronic thromboembolic pulmonary hypertension (CTEPH). The aim of this meta-analysis was to evaluate RV remodelling and function following balloon pulmonary angioplasty (BPA) in patients with inoperable CTEPH or persistent/recurrent pulmonary hypertension (PH) after pulmonary endarterectomy (PEA).

METHODS

We reviewed all studies evaluating RV function by cardiac magnetic resonance (CMR) and/or echocardiography pre- and post-BPA from PubMed/Medline prior to 15 December 2019. Ten (299 patients) of the 29 studies retrieved met the inclusion criteria: 5 CMR and 5 echocardiography studies. The systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Guidelines.

RESULTS

Pooled data from CMR studies revealed BPA resulted in a significantly decreased RV end-diastolic volume index (weighted mean difference (WMD) - 28.33 ml/m², p < 0.00001) and RV end-systolic volume index (WMD - 29.06 ml/m², p < 0.00001) accompanied by an increased RV ejection fraction (RVEF, WMD 8.97%, p < 0.00001). Data from the echocardiography studies showed BPA resulted in decreased RV basal diameter (WMD - 0.37 cm, p = 0.0009) and an increase of RV fractional area change (WMD 5.97 %, p = 0.003), but improvements of tricuspid annular plane systolic excursion (TAPSE) and S' were not significant.

CONCLUSIONS

BPA improves RVEF and decreases RV volumes in patients with inoperable CTEPH or persistent/recurrent PH after PEA.

KEY POINTS

• Balloon pulmonary angioplasty improves RVEF and decreases RV volumes in patients with inoperable CTEPH or persistent/recurrent PH after PEA.

Regional Right Ventricular Abnormalities Implicate Distinct Pathophysiological Conditions in Patients With Chronic Thromboembolic Pulmonary Hypertension

Background

Right ventricular (RV) dysfunction is a prognostic factor for cardiovascular disease. However, its mechanism and pathophysiology remain unknown. We investigated RV function using RV‐specific 3‐dimensional (3D)‐speckle‐tracking echocardiography (STE) in patients with chronic thromboembolic pulmonary hypertension. We also assessed regional wall motion abnormalities in the RV and chronological changes during balloon pulmonary angioplasty (BPA).

Methods and Results

Twenty‐nine patients with chronic thromboembolic pulmonary hypertension who underwent BPA were enrolled and underwent right heart catheterization and echocardiography before, immediately after, and 6 months after BPA. Echocardiographic assessment of RV function included both 2‐dimensional‐STE and RV‐specific 3D‐STE. Before BPA, global area change ratio measured by 3D‐STE was significantly associated with invasively measured mean pulmonary artery pressure and pulmonary vascular resistance (r=0.671 and r=0.700, respectively). Dividing the RV into the inlet, apex, and outlet, inlet area change ratio showed strong correlation with mean pulmonary artery pressure and pulmonary vascular resistance before BPA (r=0.573 and r=0.666, respectively). Only outlet area change ratio was significantly correlated with troponin T values at 6 months after BPA (r=0.470), and its improvement after BPA was delayed compared with the inlet and apex regions. Patients with poor outlet area change ratio were associated with a delay in RV reverse remodeling after treatment.

Conclusions

RV‐specific 3D‐STE analysis revealed that 3D RV parameters were novel useful indicators for assessing RV function and hemodynamics in pulmonary hypertension and that each regional RV portion presents a unique response to hemodynamic changes during treatment, implicating that evaluation of RV regional functions might lead to a new guide for treatment strategies.

Preoperative right ventricular strain predicts sustained right ventricular dysfunction after balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension

AIMS

Balloon pulmonary angioplasty (BPA) improves hemodynamics and exercise tolerance in patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, its diagnostic and predictive values remain unclear. We investigated the diagnostic and predictive values of BPA by assessing the mechanism of right ventricular (RV) dysfunction.

METHODS AND RESULTS

Hemodynamic improvement was maintained over 6 months in 99 patients with CTEPH who underwent BPA. Notably, 57 of 99 patients showed normalization of pulmonary vascular resistance (PVR) after BPA. The RV mid free wall longitudinal strain (RVMFS) was inversely correlated with the 6-min walk distance (r = -.35, P = .01) and serum levels of high-sensitivity cardiac troponin T (hs-cTNT) (r = -.39, P = .004) 6 months post-BPA in the PVR-normalized group. Among all variables analyzed, only the pre-BPA RVMFS was correlated with the post-BPA RVMFS (r = .40, P = .001), and the pre-BPA RVMFS (<-15.8%) was the strongest predictor of post-BPA normalization of RVMFS (area under the curve 0.80, P = .01, sensitivity 89%, and specificity 63%). The immediate post-BPA RVMFS showed worsening over 6 months after the procedure (-25.8% to -21.1%) in patients with high serum hs-cTNT levels (>0.0014 ng/mL). In contrast, we observed an improvement in these values in those with low serum hs-cTNT levels (-23.6% to -24.4%).

CONCLUSION

RVMFS of -15.8% may be a useful cutoff value to categorize the refractory and non-refractory stages of disease. Sustained serum hs-cTNT elevation post-BPA indicates subclinical RV myocardial injury, with resultant RVMFS deterioration and poor exercise tolerance.

Long-term changes of exercise hemodynamics and physical capacity in chronic thromboembolic pulmonary hypertension after pulmonary thromboendarterectomy

BACKGROUND

A substantial number of chronic thromboembolic pulmonary hypertension (CTEPH) patients experience dyspnea on exertion and limited exercise capacity despite surgically successful pulmonary endarterectomy (PEA). We sought to prospectively evaluate resting and peak exercise hemodynamics before, 3 and 12 months after PEA in consecutive CTEPH-patients and correlate it to physical functional capacity.

METHODS AND RESULTS

Twenty consecutive CTEPH-patients were examined. Twelve months after PEA, 75% of patients with severely increased pre-PEA mean pulmonary arterial pressure (mPAP) at rest had normal or mildly increased mPAP. However, mPAP reduction was less pronounced during exercise where only 45% had normal or mildly increased mPAP at 12 months. Hemodynamic changes during exercise were tested using the pressure-flow relationship (i.e. mPAP/cardiac output (CO) slope). The average mPAP/CO slope was 7.5 ± 4.2 mm Hg/L/min preoperatively and 3.9 ± 3.0 mm Hg/L/min at 12 months (p < .005). CO reserve (CO increase from rest to peak exercise) was increased (5.7 ± 2.9 L/min) 12 months after PEA compared with pre-PEA (2.5 ± 1.8 L/min), p < .0001. However, 12 months after PEA, the CO reserve was only 49% of that of healthy controls, p < .0001. Changes in cardiac output (∆CO), calculated as the difference between CO before PEA and 12 months later, were significantly correlated with six-minute-walk-test and peak oxygen uptake (VO2), both at rest and peak exercise.

CONCLUSION

Invasive exercise hemodynamic examination in CTEPH-patients demonstrates that after otherwise successful PEA surgery, >50% of patients have a significant increase in exercise mPAP, and the CO reserve remains compromised 12 months after PEA. Improvement in physical capacity is correlated with ∆CO.

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: State of the art

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complex chronic disease in which pulmonary artery stenosis or obstruction caused by organized thrombus can lead to increased pulmonary artery pressure and pulmonary vascular resistance, ultimately triggering progressive right heart failure and death. Currently, its exact mechanism is not fully understood. Pulmonary endarterectomy (PEA) has immediate effects with low perioperative mortality and satisfactory prognosis in experienced expert centers for CTEPH patients with proximal lesions. Nevertheless, 37% of patients are deemed unsuitable for PEA surgery due to comorbidities and other factors, and nearly half of the operated patients have residual or recurrent pulmonary hypertension. Riociguat is the only approved drug for CTEPH, although its effect is limited. Balloon pulmonary angioplasty (BPA) is a promising alternative treatment for patients with CTEPH. After more than 30 years of development and refinements, emerging evidence has confirmed its role in patients with inoperable CTEPH or residual/recurrent pulmonary hypertension, with acceptable complications and comparable long-term prognosis to PEA. This review summarizes the pathophysiology of CTEPH, BPA history and development, therapeutic principles, indications and contraindications, interventional procedures, imaging modalities, efficacy and prognosis, complications and management, bridging and hybrid therapies, ongoing clinical trials and future prospects.

Multicentre randomised controlled trial of balloon pulmonary angioplasty and riociguat in patients with chronic thromboembolic pulmonary hypertension: protocol for the MR BPA study

INTRODUCTION

Management of inoperable chronic thromboembolic pulmonary hypertension (CTEPH) remains a clinical challenge. Currently, medical treatment involving pulmonary vasodilators (such as soluble guanylate-cyclase stimulators) is recommended, primarily for ameliorating symptoms. More recently, balloon pulmonary angioplasty (BPA) has been developed as alternative treatment for inoperable CTEPH. This study aimed to compare the efficacy and safety of BPA and riociguat (a soluble guanylate-cyclase stimulator) as treatments for inoperable CTEPH.

METHODS AND ANALYSIS

This study is a multicentre randomised controlled trial. Subjects with inoperable CTEPH were randomised (1:1) into either a BPA or riociguat group, and observed for 12 months after initiation of treatment. The primary endpoint will be the change in mean pulmonary arterial pressure from baseline to 12 months after initiation of treatment. For primary analysis, we will estimate the least square means difference and 95% CI for the change of pulmonary arterial pressure between the groups at 12 months using the analysis of covariance adjusted for allocation factors.

ETHICS AND DISSEMINATION

This study and its protocols were approved by the institutional review board of Keio University School of Medicine and each participating institution. Written informed consent was obtained from all participants. Results will be disseminated at medical conferences and in journal publications.

TRIAL REGISTRATION NUMBER

University Hospital Medical Information Network Clinical Trial Registry (UMIN000019549); Pre-results.

Chronic Thromboembolic Pulmonary Hypertension: Evolving Therapeutic Approaches for Operable and Inoperable Disease

Chronic thromboembolic pulmonary hypertension (CTEPH), a rare consequence of an acute pulmonary embolism, is a disease that is underdiagnosed, and surgical pulmonary thromboendarterectomy (PTE) remains the preferred therapy. However, determination of operability is multifactorial and can be challenging. There is growing excitement for the percutaneous treatment of inoperable CTEPH with data from multiple centers around the world showing the clinical feasibility of balloon pulmonary angioplasty. Riociguat remains the only approved medical therapy for CTEPH patients deemed inoperable or with persistent pulmonary hypertension after PTE. We recommend that expert multidisciplinary CTEPH teams be developed at individual institutions. Additionally, optimal and standardized techniques for balloon pulmonary angioplasty need to be developed along with dedicated interventional equipment and appropriate training standards. In the meantime, the percutaneous revascularization option is appropriate for patients deemed inoperable in combination with targeted medical therapy, or those who have failed to benefit from surgery.

Electrocardiographic Criteria of Right Ventricular Hypertrophy in Patients with Chronic Thromboembolic Pulmonary Hypertension after Balloon Pulmonary Angioplasty

Objective Chronic thromboembolic pulmonary hypertension (CTEPH) is a progressive disease that leads to right-sided heart failure with electrocardiographic abnormalities. There are only a few reports about the effects of balloon pulmonary angioplasty for CTEPH on the electrocardiographic criteria of right ventricular hypertrophy. To determine the effect of balloon angioplasty on electrocardiography in patients with CTEPH. Methods We evaluated electrocardiograms in 19 patients (mean age, 64±10 years) who underwent balloon pulmonary angioplasty. Results We compared the hemodynamic parameters after balloon pulmonary angioplasty. The mean pulmonary artery pressure was decreased (p<0.001), and the cardiac index was increased (p=0.025) after balloon pulmonary angioplasty. The level of brain natriuretic peptide was decreased (p=0.001) after balloon pulmonary angioplasty (p<0.001). We applied 15 criteria for right ventricular hypertrophy to the patients, according to the American Heart Association recommendations of the electrocardiogram, after balloon pulmonary angioplasty. Among the criteria, the numbers of patients who met the criteria of deep S in V₆ (p=0.005) and max R in V_{1, 2}+max S in I, aV_L-S in V₁ (p=0.046) were significantly decreased after balloon pulmonary angioplasty. The mean numbers regarding the right ventricular hypertrophic criteria in each patient were significantly decreased after balloon pulmonary angioplasty (4.8±2.6 to 3.1±2.5, p=0.003). Conclusion In addition to improvement in hemodynamics, improvement in right ventricular hypertrophy was also observed using the electrocardiographic criteria in patients with CTEPH after balloon pulmonary angioplasty, suggesting that we should pay more attention to these changes.

Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is associated with several risk factors but is most frequently seen as a rare consequence of an acute pulmonary embolism. Surgical pulmonary thromboendarterectomy (PTE) is potentially curative for CTEPH with the best outcomes seen for the treatment of primarily proximal, accessible lobar or segmental disease. For surgically inoperable patients, percutaneous balloon pulmonary angioplasty (BPA) is feasible and has good short- to mid-term efficacy outcomes. This review focuses on the technique and outcomes associated with BPA which has emerged as a new therapeutic option for CTEPH.

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.

Shortening Hospital Stay Is Feasible and Safe in Patients With Chronic Thromboembolic Pulmonary Hypertension Treated With Balloon Pulmonary Angioplasty

BACKGROUND

There is no consensus on the length of hospital stay (LOHS) and post-interventional management after balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). We examined temporal trends with respect to LOHS and requirement for intensive care for BPA and their relationship with the incidence of BPA-related complications.

METHODS

From November 2012 to September 2017, a total of 123 consecutive patients with CTEPH who underwent BPA were enrolled (age: 66.0 [54.0 to 74.0], World Health Organization [WHO] functional class II/III/IV; 27/88/8). Patients were divided for analysis into 3 groups according to the date of their first BPA: early-, middle-, and late-phase groups.

RESULTS

Mean pulmonary arterial pressure decreased from 36.0 (29.0 to 45.0) to 20.0 (16.0 to 22.0) mm Hg after BPA (P < 0.001). The LOHS was 41.0 (31.0 to 54.0) days in total including all sessions and 6.6 (6.0 to 7.9) days/session. Despite no significant differences in age, baseline hemodynamics, and laboratory data among the 3 groups, there was a significant reduction in LOHS (7.9 [7.0 to 9.5], 6.5 [6.1 to 7.3], 6.0 [5.3 to 6.5] days/session, P < 0.001) and use of intensive/high care unit (100%, 93%, 46%, P < 0.001). The reduction in LOHS and intensive/high care unit use did not affect the occurrence of BPA-related complications.

CONCLUSIONS

Increasing experience with BPA was associated with a reduction in LOHS and the use of intensive/high care unit, but no change was noted in the rate of BPA-related complications. These findings suggest that the reduction in both LOHS and use of the intensive care unit for BPA is feasible and does not jeopardize the safety of the procedure.

Utility of the amplitude of RV1+SV5/6 in assessment of pulmonary hypertension

Electrocardiogram (ECG) has been widely used for assessment of right ventricular (RV) hypertrophy (RVH) in patients with pulmonary hypertension (PH). However, it still remains unclear which ECG criteria of RVH are useful to predict for the severity of PH. The aim of our study was to examine the utility of ECG findings of RVH in assessment of PH. A total of 53 patients (42 women, mean age; 57.6 ± 16.4 years) with pre-capillary PH, who were diagnosed by right heart catheterization, underwent blood sampling, ECG, and cardiac magnetic resonance within a week before the right heart catheterization. We assessed the traditional ECG criteria of RVH in PH patients, and compared to age- and gender-matched control subjects without PH confirmed by 2-dimensional echocardiography (n = 42, mean age 55.3 ± 15.9 years). We also analyzed the clinical variables associated with ECG findings in patients with PH. Mean pulmonary arterial pressure (mPAP), cardiac index, and pulmonary vascular resistance (PVR) in PH patients were 35.3 ± 11.9 mmHg, 2.82 (2.09–3.45) L/min/m², and 576 ± 376 dyne·sec·cm^-5, respectively. The prevalence of right axis deviation (43.4%), R:S ratio V₁ > 1 (32.1%), and RV₁+SV_5/6 > 10.5 mm (69.8%) in PH patients was greater than those in control subjects (p < 0.001). In univariate analysis, mPAP, PVR, RV wall thickness, RV mass index, RV volume, and RV ejection fraction (EF) (inversely) were significantly correlated with the amplitude of RV₁+SV_5/6. Multiple regression analysis revealed that mPAP and RVEF (inversely) were independently associated with the amplitude of RV₁+SV_5/6 (R² = 0.282). Also, we performed the survival analysis among pre-capillary PH patients. During a mean follow-up of 3.7 years, patients with ≥ 16.4 mm of RV₁+SV_5/6 had worse prognosis than those with < 16.4 mm (Log rank p = 0.015). In conclusion, the amplitude of SV₁+RV_5/6 could be the most useful factor reflected for RV remodeling, hemodynamics and survival in patients with pre-capillary PH.

Residual high intrapulmonary shunt fraction limits exercise capacity in patients treated with balloon pulmonary angioplasty

Balloon pulmonary angioplasty (BPA) has emerged as a new treatment strategy for patients with chronic thromboembolic pulmonary hypertension (CTEPH). Improvements in hemodynamic parameters after BPA have been reported, but some patients continue to suffer from reduced exercise tolerance even after the normalization of hemodynamic parameters following BPA. As the amelioration of hemodynamic parameters is reportedly achieved via BPA, we hypothesized that the limiting factors for exercise tolerance in these patients are related to respiratory function. Therefore, we investigated the associations between respiratory function and exercise tolerance, and the mechanisms underlying respiratory dysfunction in patients after BPA. We analyzed 62 patients with CTEPH who underwent 1-year follow-up after BPA. Predictors for reduced exercise tolerance after BPA determined with six-minute walk test were sought from pulmonary hemodynamic and respiratory parameters using logistic regression analysis. After multivariate adjustments, high mean right atrium pressure (mRAP) and high alveolar-arterial oxygen gradient (A-aDO₂) were significant predictors for reduced exercise tolerance. Next, we analyzed factors associated with high A-aDO2. Among the pathophysiological causes of high A-aDO2, including ventilation, diffusing capacity, and low ventilation-perfusion ratio, only low ventilation-perfusion ratio caused by high intrapulmonary shunt fraction was associated with high A-aDO₂. Impaired oxygenation due to residual high intrapulmonary shunt fraction was associated with reduced exercise tolerance in patients with CTEPH, after receiving BPA.

Improvement in the electrocardiograms associated with right ventricular hypertrophy after balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension

Background

Balloon pulmonary angioplasty (BPA) is a treatment option for patients with chronic thromboembolic pulmonary hypertension (CTEPH).

Methods and results

In 60 patients with CTEPH, we examined the hemodynamic data before and after BPA. In addition, the sequential ECG findings for right ventricular hypertrophy (RVH) were assessed. The mean pulmonary arterial pressure (mPAP) decreased from 38 ± 11 to 20 ± 4 mm Hg (p < 0.05). The ROC analysis showed that the S waves in V5, R waves in V1 + S waves in V5, S waves in I, and QRS axis were significant predictors of an mPAP ≧ 30 mm Hg (AUC > 0.75, p < 0.01). The predictive values for the mPAP before the BPA were the S and R waves in lead V6, and P waves in lead II (33.417 + 0.078 × P in II − 0.10 × R in V6 + 0.012 × S in V6). The change in the mPAP (ΔmPAP) correlated with the change in the amplitudes of the ECGs: ΔS wave in lead I (R = 0.544, p < 0.001), ΔR in V1 + S in V5 (R = 0.476, p < 0.001), and ΔP wave in II (R = 0.511, p < 0.001). At 6 months of follow-up, the improvement in an R in V1 + S in V5 of ≧10 mm implied a better functional status.

Conclusion

BPA therapy reduced the pulmonary arterial pressure in patients with CTEPH and was associated with an improvement in the ECG findings related to RVH.

Prognostic value of three-dimensional echocardiographic right ventricular ejection fraction in patients with pulmonary arterial hypertension

Background

Right ventricular (RV) function is an independent predictor of clinical outcomes in patients with pulmonary arterial hypertension (PAH). However, it remains controversial which RV parameter should be measured as an appropriate index for the treatment of PAH. The aim of this study was to identify the most useful parameter that correlates with hemodynamics and predicts clinical outcomes in PAH.

Results

Most of the clinical and echocardiographic RV parameters were significantly correlated with pulmonary vascular resistance (PVR) as well as mean pulmonary arterial pressure (mPAP). Among these, three dimensional right ventricular ejection fraction (3DRVEF) showed the strongest hemodynamic correlation, followed by 6-minute walk distance. Receiver operating characteristic analysis of association with cardiac events including death, hospitalization, and intervention revealed a greater area under the curve for 3DRVEF than for mPAP (0.78 vs. 0.74). Kaplan-Meier analysis showed that patients with 3DRVEF less than 38% had significantly shorter event-free survival than those with greater than 38% (P = 0.0007). Finally, the Cox proportional hazards analysis revealed that 3DRVEF, but not mPAP, was an independent predictor of clinical events in PAH.

Materials and Methods

Eighty-six consecutive patients were enrolled in this study. RV hemodynamic parameters were measured by right heart catheterization (RHC). RV function was assessed using two-dimensional speckle-tracking echocardiography and three-dimensional transthoracic echocardiography (3DTTE) to evaluate RV free wall global strain (RVFS) and RVEF.

Conclusions

RVEF measured by 3DTTE could be a useful parameter for noninvasively assessing RV hemodynamics and predicting the clinical outcomes in PAH patients.

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.

The clinical value of assessing right ventricular diastolic function after balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) has a poor prognosis because of the associated progressive right heart failure. Accurate evaluation of right ventricular (RV) function would thus be useful to predict prognosis. However, the significance of RV diastolic function remains unclear. We aimed to identify which echocardiographic measures are most accurate, and potentially useful, in assessing RV diastolic function in patients with CTEPH, and to study the effects of balloon pulmonary angioplasty (BPA) on them. We enrolled 53 CTEPH patients who underwent BPA. Echocardiographic parameters, including two-dimensional speckle-tracking echocardiography, were compared to the hemodynamic parameters measured by right heart catheterization before and after BPA. RV strain rate during early diastole (SR_E), tricuspid e' and right atrial area (RAA) were ameliorated after BPA, concomitant with a decrease in the time constant of the RV pressure curve during diastole (tau), indicating the improvement of RV diastolic function. Among them, SR_E had the strongest correlation with tau (r = - 0.39, p < 0.001). Furthermore, the receiver operating characteristic analyses revealed that E/SR_E (AUC 0.704) and inferior vena cava diameter (AUC 0.726) had a stronger association with higher mean right atrial pressure than RAA (AUC 0.632). In contrast, RAA had a stronger correlation with 6 min-walk distances than SR_E (r = - 0.39, p < 0.001 vs. r = 0.30, p = 0.005). Taken together, echocardiographic assessment of RV diastolic function might be associated with hemodynamics as well as exercise tolerance in patients with CTEPH, indicating its benefits in evaluating the therapeutic effects of BPA.

Three-dimensional fractal analysis of 99mTc-MAA SPECT images in chronic thromboembolic pulmonary hypertension for evaluation of response to balloon pulmonary angioplasty: association with pulmonary arterial pressure

OBJECTIVE

Balloon pulmonary angioplasty (BPA) is used for inoperable chronic thromboembolic pulmonary hypertension (CTEPH), but its effect cannot be evaluated noninvasively. We devised a noninvasive quantitative index of response to BPA using three-dimensional fractal analysis (3D-FA) of technetium-99m-macroaggregated albumin (Tc-MAA) single-photon emission computed tomography (SPECT).

PATIENTS AND METHODS

Forty CTEPH patients who underwent pulmonary perfusion scintigraphy and mean pulmonary arterial pressure (mPAP) measurement by right heart catheterization before and after BPA were studied. The total uptake volume (TUV) in bilateral lungs was determined from maximum intensity projection Tc-MAA SPECT images. Fractal dimension was assessed by 3D-FA. Parameters were compared before and after BPA, and between patients with post-BPA mPAP more than 30 mmHg and less than or equal to 30 mmHg. Receiver operating characteristic analysis was carried out.

RESULTS

BPA significantly improved TUV (595±204-885±214 ml, P<0.001) and reduced the laterality of uptake (238±147-135±131 ml, P<0.001). Patients with poor therapeutic response (post-BPA mPAP≥30 mmHg, n=16) showed a significantly smaller TUV increase (P=0.044) and a significantly greater post-BPA fractal dimension (P<0.001) than the low-mPAP group. Fractal dimension correlated with mPAP values before and after BPA (P=0.013 and 0.001, respectively). A post-BPA fractal dimension threshold of 2.4 distinguished between BPA success and failure with 75% sensitivity, 79% specificity, 78% accuracy, and area under the curve of 0.85.

CONCLUSION

3D-FA using Tc-MAA SPECT pulmonary perfusion scintigraphy enables a noninvasive evaluation of the response of CTEPH patients to BPA.

Riociguat, a soluble guanylate cyclase stimulator, ameliorates right ventricular contraction in pulmonary arterial hypertension

Riociguat is a soluble guanylate cyclase stimulator used for pulmonary hypertension (PH) treatment. We evaluated right ventricular (RV) contractile function in 27 PH patients receiving riociguat. A comparison of pre- and post-administration echocardiographic studies demonstrated significantly improved RV strain after riociguat treatment, even after adjusting for RV afterload.

Balloon Pulmonary Angioplasty in Chronic Thromboembolic Pulmonary Hypertension: New Horizons in the Interventional Management of Pulmonary Embolism

Chronic thromboembolic pulmonary hypertension (CTEPH) is an underdiagnosed potential complication of acute or recurrent pulmonary thromboembolic disease. Multiple studies suggest that up to 5% of patients with acute pulmonary thromboembolic disease go on to develop CTEPH. The prognosis of untreated CTEPH is poor, but advances in medical and surgical treatments over the past few decades have improved patient outcomes. The gold standard and curative treatment for CTEPH is pulmonary endarterectomy; however, some patients are inoperable and others who have undergone pulmonary endarterectomy experience persistent or recurrent pulmonary hypertension despite medical therapy. In recent years, balloon pulmonary angioplasty has emerged as a primary and adjunctive treatment for these CTEPH patients at expert or specialized centers. This review outlines an approach to balloon pulmonary angioplasty for CTEPH, including clinical presentation and evaluation; patient selection and indications; treatment planning; equipment and technique; overcoming technical challenges; recognition and management of complications; postprocedural care and clinical follow-up; and expected outcomes.

The pathophysiology of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare, progressive pulmonary vascular disease that is usually a consequence of prior acute pulmonary embolism. CTEPH usually begins with persistent obstruction of large and/or middle-sized pulmonary arteries by organised thrombi. Failure of thrombi to resolve may be related to abnormal fibrinolysis or underlying haematological or autoimmune disorders. It is now known that small-vessel abnormalities also contribute to haemodynamic compromise, functional impairment and disease progression in CTEPH. Small-vessel disease can occur in obstructed areas, possibly triggered by unresolved thrombotic material, and downstream from occlusions, possibly because of excessive collateral blood supply from high-pressure bronchial and systemic arteries. The molecular processes underlying small-vessel disease are not completely understood and further research is needed in this area. The degree of small-vessel disease has a substantial impact on the severity of CTEPH and postsurgical outcomes. Interventional and medical treatment of CTEPH should aim to restore normal flow distribution within the pulmonary vasculature, unload the right ventricle and prevent or treat small-vessel disease. It requires early, reliable identification of patients with CTEPH and use of optimal treatment modalities in expert centres.

Balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is thought to result from incomplete resolution of pulmonary thromboemboli that undergo organisation into fibrous tissue within pulmonary arterial branches, filling pulmonary arterial lumina with collagenous obstructions. The treatment of choice is pulmonary endarterectomy (PEA) in CTEPH centres, which has low post-operative mortality and good long-term survival. For patients ineligible for PEA or who have recurrent or persistent pulmonary hypertension after surgery, medical treatment with riociguat is beneficial. In addition, percutaneous balloon pulmonary angioplasty (BPA) is an emerging option, and promises haemodynamic and functional benefits for inoperable patients. In contrast to conventional angioplasty, BPA with undersized balloons over guide wires exclusively breaks intraluminal webs and bands, without dissecting medial vessel layers, and repeat sessions are generally required. Observational studies report that BPA improves haemodynamics, symptoms and functional capacity in patients with CTEPH, but controlled trials with long-term follow-up are needed. Complications include haemoptysis, wire injury, vessel dissection, vessel rupture, reperfusion pulmonary oedema, pulmonary parenchymal bleeding and haemorrhagic pleural effusions. This review summarises the available evidence for BPA, patient selection, recent technical refinements and periprocedural imaging, and discusses the potential future role of BPA in the management of CTEPH.

Balloon pulmonary angioplasty is an emerging percutaneous vascular intervention for non-operable CTEPHhttp://ow.ly/tIN3309hys3

Midterm Effect of Balloon Pulmonary Angioplasty on Hemodynamics and Subclinical Myocardial Damage in Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

The acute favourable effect of balloon pulmonary angioplasty (BPA) has been proven in patients with chronic thromboembolic pulmonary hypertension (CTEPH). However, data on its effect 6 months after therapy (from now on referred to as mid-term) and influence on the right ventricle and myocardial damage are sparse. To evaluate factors that influence improvement in cardiac output (CO) and subclinical myocardial damage, we examined hemodynamics and serum high-sensitivity troponin T (hs-TnT) levels before, 1 week after, and 6 months after BPA.

METHODS

In a retrospective study, we reviewed 67 consecutive patients from November 2012 to January 2016 with CTEPH who had undergone BPA at Keio University Hospital.

RESULTS

Six months after BPA, the mean right atrium pressure, mean pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR), B-type natriuretic peptide (BNP), and hs-TnT levels decreased; CO and 6-minute walking distance increased. Changes in CO and hs-TnT levels varied compared with other hemodynamic parameters and BNP levels. The CO-increase group (n = 42) had higher mean PAP and PVR, and lower CO at baseline than the CO-decrease/stable group (n = 25). The hs-TnT-decrease group (n = 36) had higher mean right atrium pressure, PAP, PVR, and BNP levels, and lower CO at baseline than the hs-TnT-increase/stable group (n = 31).

CONCLUSIONS

Six months after BPA, hemodynamics and exercise capacity improved and hs-TnT levels decreased. Improvements in CO and hs-TnT levels were more prominent in CTEPH patients with impaired baseline hemodynamics, suggesting that BPA has a favourable mid-term effect on hemodynamics and subclinical myocardial damage in patients with CTEPH, especially in those with impaired hemodynamics.

Right ventricular dyssynchrony predicts clinical outcomes in patients with pulmonary hypertension

BACKGROUND

RV dyssynchrony has been described in patients with pulmonary hypertension (PH) and is an independent predictor of clinical worsening; however, the optimal method for measuring RV dyssynchrony has not been fully established. This study aimed to investigate whether RV dyssynchrony is correlated with hemodynamics and prognosis in PH patients and to identify the best parameter for evaluating RV dyssynchrony.

METHODS

This study assessed 100 PH patients, measuring mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), and cardiac index (CI) by right heart catheterization (RHC). RV strain curves were obtained using two-dimensional speckle-tracking echocardiography (2DSTE), and time from QRS onset to maximum peak longitudinal strain (T_max) or time to first peak (T_first) was measured. Difference in time between the earliest and the latest segment (TD) and standard deviation (SD) of T in 6 segments with RV apex (-SD6) and 4 segments without RV apex (-SD4) were also assessed.

RESULTS

Among all RV dyssynchrony parameters, T_max-SD6 showed the strongest correlation with RV hemodynamics such as mPAP (R²=0.27, P<0.0001) and PVR (R²=0.22, P<0.0001). Univariate and multivariate Cox proportional hazard analyses showed that T_max-SD6 significantly correlated with and independently predicted event-free survival in patients with PH.

CONCLUSIONS

RV dyssynchrony is a useful index for RV function and an independent predictor of clinical outcomes in patients with PH. In addition, the inclusion of apical motion is essential for the optimal assessment of RV dyssynchrony.

Changes in Right Ventricular Dysfunction After Balloon Pulmonary Angioplasty in Patients With Chronic Thromboembolic Pulmonary Hypertension

The aim was to investigate the effect of balloon pulmonary angioplasty (BPA) on right ventricular (RV) function in chronic thromboembolic pulmonary hypertension. Twenty-six patients with chronic thromboembolic pulmonary hypertension were enrolled and were divided into 2 groups, group H with high (>30 mm Hg) mean pulmonary arterial pressure and group L with low (25 to 30 mm Hg) mean pulmonary arterial pressure. RV function was assessed using 2-dimensional speckle-tracking echocardiography as well as 3-dimensional echocardiography, and RV dyssynchrony was assessed by the RV strain curves. Exercise capacity was evaluated by the 6-minute walk distance. RV dilatation was significantly reduced after BPA. In group H, RV ejection fraction, RV free wall longitudinal strain and RV dyssynchrony were all impaired before BPA and were ameliorated after BPA. In group L, RV ejection fraction as well as RV dyssynchrony were impaired without the reduction of RV free wall longitudinal strain and were improved after BPA, indicating that RV dysfunction may be attributable to the RV dyssynchrony in group L. Furthermore, RV dyssynchrony at baseline was the only parameter that was correlated with improvement in the 6-minute walk distance after BPA. RV dyssynchrony may affect RV function and could be the useful parameter for clinical outcome after BPA.