Reverse right ventricular remodeling after pulmonary endarterectomy in patients with chronic thromboembolic pulmonary hypertension: Utility of magnetic resonance imaging to demonstrate restoration of the right ventricle

Cardiothoracic Imaging for Outcome Prediction in Chronic Thromboembolic Pulmonary Hypertension after Pulmonary Endarterectomy or Balloon Pulmonary Angioplasty: A Scoping Review

There has been a rapid expansion in centers performing balloon pulmonary angioplasty (BPA) and pulmonary thromboendarterectomy (PTE) for chronic thromboembolic pulmonary hypertension (CTEPH). The purpose of this scoping review was to identify cardiothoracic imaging predictors of outcomes and to identify gaps to address in future work. A scoping review was conducted using the framework outlined by Arksey and O'Malley and Levac et al. in MEDLINE and EMBASE. The study protocol was preregistered in OSF Registries and performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR) guidelines. There were 1117 identified studies, including 48 involving pulmonary thromboendarterectomy (n = 25) and balloon pulmonary angioplasty (n = 23). CT was the most common preoperative imaging modality used (n = 21) and CT level of disease was the most reported imaging predictor of outcomes for pulmonary thromboendarterectomy. Although must studies evaluated hemodynamic improvements, imaging was of additional use in predicting clinically significant procedural complications after balloon pulmonary angioplasty, as well as mortality and long-term outcome after pulmonary endarterectomy. Predictors reported in MRI and digital subtraction angiography were less commonly reported and warrant multicenter validation. Cardiothoracic imaging may predict clinically significant outcomes after balloon pulmonary angioplasty and pulmonary thromboendarterectomy. Radiologists involved in the assessment of CTEPH patients should be aware of key predictors and future investigations could focus on multicenter validation and new technologies.

Chronic Thromboembolic Pulmonary Hypertension: Clinical and Imaging Evaluation

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of pulmonary embolism and is an important cause of pulmonary hypertension. As a clinical entity, it is frequently underdiagnosed with prolonged diagnostic delays. This study reviews the clinical and radiographic findings associated with CTEPH to improve awareness and recognition. Strengths and limitations of multiple imaging modalities are reviewed. Accompanying images are provided to supplement the text and provide examples of important findings for the reader.

Long-term effects of pulmonary endarterectomy on pulmonary hemodynamics, cardiac function, and exercise capacity in chronic thromboembolic pulmonary hypertension

BACKGROUND

Long-term changes in exercise capacity and cardiopulmonary hemodynamics after pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) have been poorly described.

METHODS

We analyzed the data from 2 prospective surgical CTEPH cohorts in Hammersmith Hospital, London, and Amsterdam UMC. A structured multimodal follow-up was adopted, consisting of right heart catheterization, cardiac magnetic resonance imaging, and cardiopulmonary exercise testing before and after PEA. Preoperative predictors of residual pulmonary hypertension (PH; mean pulmonary artery pressure >20 mm Hg and pulmonary vascular resistance ≥2 WU) and long-term exercise intolerance (VO2max <80%) at 18 months were analyzed.

RESULTS

A total of 118 patients (61 from London and 57 from Amsterdam) were included in the analysis. Both cohorts displayed a significant improvement of pulmonary hemodynamics, right ventricular (RV) function, and exercise capacity 6 months after PEA. Between 6 and 18 months after PEA, there were no further improvements in hemodynamics and RV function, but the proportion of patients with impaired exercise capacity was high and slightly increased over time (52%-59% from 6 to 18 months). Long-term exercise intolerance was common and associated with preoperative diffusion capacity for carbon monoxide (DLCO), preoperative mixed venous oxygen saturation, and postoperative PH and right ventricular ejection fraction (RVEF). Clinically significant RV deterioration (RVEF decline >3%; 5 [9%] of 57 patients) and recurrent PH (5 [14%] of 36 patients) rarely occurred beyond 6 months after PEA. Age and preoperative DLCO were predictors of residual PH post-PEA.

CONCLUSIONS

Restoration in exercise tolerance, cardiopulmonary hemodynamics, and RV function occurs within 6 months. No substantial changes occurred between 6 and 18 months after PEA in the Amsterdam cohort. Nevertheless, long-term exercise intolerance is common and associated with postoperative RV function.

Characteristics and prognostic significance of right heart remodeling and tricuspid regurgitation after pulmonary endarterectomy

OBJECTIVE

Right heart remodeling and tricuspid regurgitation (TR) are common in patients with chronic thromboembolic pulmonary hypertension. This study aimed to investigate the significance of right heart remodeling and TR after pulmonary endarterectomy (PEA) in patients with chronic thromboembolic pulmonary hypertension.

METHODS

Patients who underwent PEA with preoperative and postoperative transthoracic echocardiograms at our center between June 2010 and July 2019 were retrospectively reviewed. The composite end point was defined as death or hospitalization due to worsening heart failure, bleeding, or recurrent pulmonary embolism.

RESULTS

In total, 158 patients were included for analysis. Right ventricular basal (48 [45-52] vs 43 [39-47] mm, P < .001), midcavitary (46 [42-50] vs 38 [34-42] mm, P < .001), and longitudinal dimensions (87 [83-93] vs 80 [75-84] mm, P < .001), along with the right atrial volume index (37 [25-51] vs 24 [18-34] mL/m2, P < .001), significantly decreased, whereas left ventricular and atrial sizes and left ventricular ejection fraction increased after PEA. Overall, 78 patients (49%) showed significant TR on preoperative transthoracic echocardiograms, and 33 (21%) had significant residual TR after PEA. Fourteen patients died, and 24 patients met the composite end point. Residual TR after PEA was independently associated with mortality (P = .005) and the composite end point (P = .003). Patients with residual TR had significantly worse survival (log-rank P < .001) and greater event rates (log-rank P = .003) than those without residual TR.

CONCLUSIONS

Significant improvements in right heart remodeling were seen following PEA. However, residual TR was a poor prognostic marker.

Meijboom L, Symersky P, Winkelman JA, Nossent EJ, Aman J, Bogaard HJ, Vonk Noordegraaf A, van Es J. Patients with CTEPH and mild hemodynamic severity of disease improve to a similar level of exercise capacity after pulmonary endarterectomy compared to patients with severe hemodynamic disease

The correlation between hemodynamics and degree of pulmonary vascular obstruction (PVO) is known to be poor in chronic thromboembolic pulmonary hypertension (CTEPH), which makes the selection of patients eligible for pulmonary endarterectomy (PEA) challenging. It can be postulated that patients with similar PVO but different hemodynamic severity have different postoperative hemodynamics and exercise capacity. Therefore, we aimed to assess the effects of PEA on hemodynamics and exercise physiology in mild and severe CTEPH patients. We retrospectively studied 18 CTEPH patients with a mild hemodynamic profile (mean pulmonary arterial pressure [mPAP] between 25 and 30 mmHg at rest) and CTEPH patients with a more severe hemodynamic profile (mPAP > 30 mmHg), matched by age, gender, and PVO. Cardiopulmonary exercise testing parameters were evaluated at baseline and 18 months following PEA. At baseline, exercise capacity, defined as oxygen uptake, was less severely impaired in the mild CTEPH group compared to the severe CTEPH group. After PEA, in the mild CTEPH group, ventilatory efficiency and oxygen pulse improved significantly (p < 0.05), however, the change in ventilatory efficiency and oxygen pulse was smaller compared to the severe CTEPH group. Only in the severe CTEPH group exercise capacity improved significantly (p < 0.001). Hence, in the present study, postoperative hemodynamic outcome and the CPET-determined recovery of exercise capacity in mild CTEPH patients did not differ from a matched group of severe CTEPH patients.

Functional and molecular determinants of right ventricular response to severe pulmonary hypertension in a large animal model

Right ventricular (RV) failure is the major determinant of outcome in pulmonary hypertension (PH). Calves exposed to 2-wk hypoxia develop severe PH and unlike rodents, hypoxia-induced PH in this species can lead to right heart failure. We, therefore, sought to examine the molecular and structural changes in the RV in calves with hypoxia-induced PH, hypothesizing that we could identify mechanisms underlying compensated physiological function in the face of developing severe PH. Calves were exposed to 14 days of environmental hypoxia (equivalent to 4,570 m/15,000 ft elevation, n = 29) or ambient normoxia (1,525 m/5,000 ft, n = 25). Cardiopulmonary function was evaluated by right heart catheterization and pressure volume loops. Molecular and cellular determinants of RV remodeling were analyzed by cDNA microarrays, RealTime PCR, proteomics, and immunochemistry. Hypoxic exposure induced robust PH, with increased RV contractile performance and preserved cardiac output, yet evidence of dysregulated RV-pulmonary artery mechanical coupling as seen in advanced disease. Analysis of gene expression revealed cellular processes associated with structural remodeling, cell signaling, and survival. We further identified specific clusters of gene expression associated with 1) hypertrophic gene expression and prosurvival mechanotransduction through YAP-TAZ signaling, 2) extracellular matrix (ECM) remodeling, 3) inflammatory cell activation, and 4) angiogenesis. A potential transcriptomic signature of cardiac fibroblasts in RV remodeling was detected, enriched in functions related to cell movement, tissue differentiation, and angiogenesis. Proteomic and immunohistochemical analysis confirmed RV myocyte hypertrophy, together with localization of ECM remodeling, inflammatory cell activation, and endothelial cell proliferation within the RV interstitium. In conclusion, hypoxia and hemodynamic load initiate coordinated processes of protective and compensatory RV remodeling to withstand the progression of PH.NEW & NOTEWORTHY Using a large animal model and employing a comprehensive approach integrating hemodynamic, transcriptomic, proteomic, and immunohistochemical analyses, we examined the early (2 wk) effects of severe PH on the RV. We observed that RV remodeling during PH progression represents a continuum of transcriptionally driven processes whereby cardiac myocytes, fibroblasts, endothelial cells, and proremodeling macrophages act to coordinately maintain physiological homeostasis and protect myocyte survival during chronic, severe, and progressive pressure overload.

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.

The Role of Strain by Cardiac Magnetic Resonance Imaging in Predicting the Prognosis of Patients with Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by thrombotic obstruction of the pulmonary arteries, and right ventricular (RV) dysfunction is a major cause of death. Cardiac magnetic resonance (CMR) is the gold standard for assessing heart wall deformation; therefore, we aimed to determine the prognostic value of CMR strain in patients with CTEPH. Strain derived by CMR was measured at the time of diagnosis in 45 patients with CTEPH, and the relationship between RV strain and prognosis was determined through follow-up. The value of RV strain in the prognostic model was compared with that of pulmonary arterial hypertension (PAH) risk stratification. The RV global peak longitudinal strain (GLS) and global peak circumferential strain (GCS) in CTEPH patients were lower than the normal references of RV strain in the control group. GLS and longitudinal strain in the basal segment were independent risk factors for adverse events (P < .050). Adding CMR parameters to PAH risk stratification improved its predictive power in patients with CTEPH. GLS and GCS scores were impaired in patients with chronic RV overload. RV strain derived by CMR imaging is a promising noninvasive tool for the follow-up of patients with 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.

4D flow cardiovascular magnetic resonance recovery profiles following pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension

BACKGROUND

Four-dimensional flow cardiovascular magnetic resonance imaging (4D flow CMR) allows comprehensive assessment of pulmonary artery (PA) flow dynamics. Few studies have characterized longitudinal changes in pulmonary flow dynamics and right ventricular (RV) recovery following a pulmonary endarterectomy (PEA) for patients with chronic thromboembolic pulmonary hypertension (CTEPH). This can provide novel insights of RV and PA dynamics during recovery. We investigated the longitudinal trajectory of 4D flow metrics following a PEA including velocity, vorticity, helicity, and PA vessel wall stiffness.

METHODS

Twenty patients with CTEPH underwent pre-PEA and > 6 months post-PEA CMR imaging including 4D flow CMR; right heart catheter measurements were performed in 18 of these patients. We developed a semi-automated pipeline to extract integrated 4D flow-derived main, left, and right PA (MPA, LPA, RPA) volumes, velocity flow profiles, and secondary flow profiles. We focused on secondary flow metrics of vorticity, volume fraction of positive helicity (clockwise rotation), and the helical flow index (HFI) that measures helicity intensity.

RESULTS

Mean PA pressures (mPAP), total pulmonary resistance (TPR), and normalized RV end-systolic volume (RVESV) decreased significantly post-PEA (P < 0.002). 4D flow-derived PA volumes decreased (P < 0.001) and stiffness, velocity, and vorticity increased (P < 0.01) post-PEA. Longitudinal improvements from pre- to post-PEA in mPAP were associated with longitudinal decreases in MPA area (r = 0.68, P = 0.002). Longitudinal improvements in TPR were associated with longitudinal increases in the maximum RPA HFI (r=-0.85, P < 0.001). Longitudinal improvements in RVESV were associated with longitudinal decreases in MPA fraction of positive helicity (r = 0.75, P = 0.003) and minimum MPA HFI (r=-0.72, P = 0.005).

CONCLUSION

We developed a semi-automated pipeline for analyzing 4D flow metrics of vessel stiffness and flow profiles. PEA was associated with changes in 4D flow metrics of PA flow profiles and vessel stiffness. Longitudinal analysis revealed that PA helicity was associated with pulmonary remodeling and RV reverse remodeling following a PEA.

Atrioventricular plane displacement and regional function to predict outcome in pulmonary arterial hypertension

To investigate if left and right atrioventricular plane displacement (AVPD) or regional contributions to SV are prognostic for outcome in patients with pulmonary arterial hypertension (PAH). Seventy-one patients with PAH and 20 sex- and age-matched healthy controls underwent CMR. Myocardial borders and RV insertion points were defined at end diastole and end systole in cine short-axis stacks to compute biventricular volumes, lateral (SVlat%) and septal (SVsept%) contribution to stroke volume. Eight atrioventricular points were defined at end diastole and end systole in 2-, 3- and 4-chamber cine long-axis views for computation of AVPD and longitudinal contribution to stroke volume (SVlong%). Cut-off values for survival analysis were defined as two standard deviations above or below the mean of the controls. Outcome was defined as death or lung transplantation. Median follow-up time was 3.6 [IQR 3.7] years. Patients were 57 ± 19 years (65% women) and controls 58 ± 15 years (70% women). Biventricular AVPD, SVlong% and ejection fraction (EF) were lower and SVlat% was higher, while SVsept% was lower in PAH compared with controls. In PAH, transplantation-free survival was lower below cut-off for LV-AVPD (hazard ratio [HR] = 2.1, 95%CI 1.2-3.9, p = 0.02) and RV-AVPD (HR = 9.8, 95%CI 4.6-21.1, p = 0.005). In Cox regression analysis, lower LV-AVPD and RV-AVPD inferred lower transplantation-free survival (LV: HR = 1.16, p = 0.007; RV: HR = 1.11, p = 0.01; per mm decrease). LV-SVlong%, RV-SVlong%, LV-SVlat%, RV-SVlat%, SVsept% and LV- and RVEF did not affect outcome. Low left and right AVPD were associated with outcome in PAH, but regional contributions to stroke volume and EF were not.

Right ventricle remodeling in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is an underdiagnosed, but potentially curable pulmonary vascular disease. The increased pulmonary vascular resistance in CTEPH is caused by unresolved proximal thrombus and secondary microvasculopathy in the pulmonary vasculature, leading to adaptive and maladaptive remodeling of the right ventricle (RV), eventual right heart failure, and death. Knowledge on the RV remodeling process in CTEPH is limited. The progression to RV failure in CTEPH is a markedly slower process. A detailed understanding of the pathophysiology and underlying mechanisms of RV remodeling may facilitate early diagnosis and the development of targeted therapy. While ultrasound, magnetic resonance imaging, right heart catheterization, and serum biomarkers have been used to assess cardiac function, the current treatment strategies reduce the afterload of the right heart, but are less effective in improving the maladaptive remodeling of the right heart. This review systematically summarizes the current knowledge on adaptive and maladaptive remodeling of the right heart in CTEPH from molecular mechanisms to clinical practice.

EGR1 Is Implicated in Right Ventricular Cardiac Remodeling Associated with Pulmonary Hypertension

Background: Pulmonary hypertension (PH) is a vasoconstrictive disease characterized by elevated mean pulmonary arterial pressure (mPAP) at rest. Idiopathic pulmonary arterial hypertension (iPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) represent two distinct subtypes of PH. Persisting PH leads to right ventricular (RV) hypertrophy, heart failure, and death. RV performance predicts survival and surgical interventions re-establishing physiological mPAP reverse cardiac remodeling. Nonetheless, a considerable number of PH patients are deemed inoperable. The underlying mechanism(s) governing cardiac regeneration, however, remain largely elusive. Methods: In a longitudinal approach, we profiled the transcriptional landscapes of hypertrophic RVs and recovered hearts 3 months after surgery of iPAH and CTEPH patients. Results: Genes associated with cellular responses to inflammatory stimuli and metal ions were downregulated, and cardiac muscle tissue development was induced in iPAH after recovery. In CTEPH patients, genes related to muscle cell development were decreased, and genes governing cardiac conduction were upregulated in RVs following regeneration. Intriguingly, early growth response 1 (EGR1), a profibrotic regulator, was identified as a major transcription factor of hypertrophic RVs in iPAH and CTEPH. A histological assessment confirmed our biocomputational results, and suggested a pivotal role for EGR1 in RV vasculopathy. Conclusion: Our findings improved our understanding of the molecular events driving reverse cardiac remodeling following surgery. EGR1 might represent a promising candidate for targeted therapy of PH patients not eligible for surgical treatment.

Imaging in Women with Heart Failure: Sex-specific Characteristics and Current Challenges

Cardiovascular disease (CVD) represents a significant threat to women's health. Heart failure (HF) is one CVD that still has an increasing incidence and about half of all cases involve women. HF is characterised by strong sex-specific features in aetiology, clinical manifestation and outcomes. Women are more likely to have hypertensive heart disease and HF with preserved ejection fraction, they experience worse quality of life but have a better overall survival rate. Women's hearts also have unique morphological characteristics that should be considered during cardiovascular assessment. It is important to understand and highlight these sex-specific features to be able to provide a tailored diagnostic approach and therapeutic management. The aim of this article is to review these aspects together with the challenges and the unique characteristics of different imaging modalities used for the diagnosis and follow-up of women with HF.

Cardiac biomarkers as indicators of right ventricular dysfunction and recovery in chronic thromboembolic pulmonary hypertension patients after balloon pulmonary angioplasty therapy - a cardiac magnetic resonance imaging cohort study

Background

In chronic thromboembolic pulmonary hypertension, right heart failure determines outcome. Balloon pulmonary angioplasty therapy allows right heart recovery, which can be monitored by cardiac magnetic resonance imaging. This study evaluates whether cardiac biomarkers (NT-proBNP, MR-proANP, sST2, and PAPP-A) are associated with cardiac magnetic resonance imaging findings prior to and after balloon pulmonary angioplasty therapy.

Methods

This observational cohort study enrolled 22 chronic thromboembolic pulmonary hypertension patients who underwent balloon pulmonary angioplasty therapy and completed a six-month follow-up including cardiac magnetic resonance imaging. Biomarker levels were compared with findings for right heart morphology and function derived from cardiac magnetic resonance imaging.

Results

Pulmonary hemodynamics improved after balloon pulmonary angioplasty therapy [pulmonary vascular resistance: 7.7 (6.0–9.0) vs. 4.7 (3.5–5.5) wood units, p < 0.001; mean pulmonary artery pressure 41 (38–47) vs. 32 (28–37) mmHg, p < 0.001]. Cardiac magnetic resonance imaging findings indicated right heart maladaptation at baseline and recovery after therapy [right ventricular end-diastolic volume 192 (141–229) ml vs. 143 (128–172) ml, p = 0.002; right ventricular end-systolic volume 131 (73–157) ml vs. 77 (61–99) ml (p < 0.001); right ventricular ejection fraction (RVEF) 34 (28–41) % vs. 52 (41–54) %; p < 0.001]. Biomarker level cut-offs [NT-proBNP 347 ng/L (area under the curve (AUC) 0.91), MR-proANP 230 pg/L (AUC 0.78), PAPP-A 14.5 mU/L (AUC 0.81), and sST2 48.0 ng/ml (AUC 0.88)] indicated a RVEF ≤ 35% at baseline. The dynamics of NT-proBNP (rs = −0.79; p < 0.001), MR-proANP (rs = –0.80; p < 0.001), and sST2 (rs = –0.49; p = 0.02) correlated inversely with the improvement in RVEF after therapy. A relative decrease of NT-proBNP < 53% (AUC 0.86) and MR-proANP < 24% (AUC 0.82) indicated a limited RVEF response.

Conclusions

In chronic thromboembolic pulmonary hypertension patients, cardiac magnetic resonance imaging findings illustrate right heart failure and recovery after balloon pulmonary angioplasty therapy. Cardiac biomarker levels correlate with right heart parameters at baseline and their dynamics after therapy.

Raising the bar to ultradisciplinary collaborations in management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is an underdiagnosed and potentially fatal subgroup of pulmonary hypertension, if left untreated. Clinical signs include exertional dyspnea and non-specific symptoms. Diagnosis requires multimodality imaging and heart catheterization. Pulmonary endarterectomy, an open heart surgery, is the gold standard treatment of choice in selected patients in specialized centers. Targeted medical therapy and balloon pulmonary angioplasty can be effective in high-risk patients with significant comorbidities, distal pulmonary vascular obstructions, or recurrent/persistent pulmonary hypertension after pulmonary endarterectomy. Currently, there is a limited number of data regarding novel coronavirus-2019 infection in patients with chronic thromboembolic pulmonary hypertension and the changing spectrum of the disease during the pandemic. Challenging times during this outbreak due to healthcare crisis and relatively higher case-fatality rates require convergence; that is an ultradisciplinary collaboration, which crosses disciplinary and sectorial boundaries to develop integrated knowledge and new paradigms. Management strategies for the "new normal" such as virtual care, preparedness for further threats, redesigned standards and working conditions, reevaluation of specific recommendations, and online collaborations for optimal decisions for chronic thromboembolic pulmonary hypertension patients may change the poor outcomes.

Pulmonary artery obstruction index, pulmonary artery diameter and right ventricle strain as prognostic CT findings in patient with acute pulmonary embolism

OBJECTIVE

This study was designed to determine predictors of pulmonary hypertension and signs of right heart dysfunction caused by pulmonary embolism (PE) that may lead to early detection of high-risk patients. So the predictive value of pulmonary artery obstruction index (PAOI), measured by pulmonary CT angiography (PCTA) in the acute setting, in predicting the patients susceptible to PE cardiac complications was evaluated. Also two other PCTA indices, pulmonary artery diameter (PAD), and right ventricle (RV) strain, in these patients were investigated and their predictive value for cardiac complications on follow up echocardiography were demonstrated.

MATERIALS AND METHODS

In the study 120 patients with a definite diagnosis of PE were included. The PAOI, PAD and RV strain were measured using PCTA at the time of the initial diagnosis. Transthoracic echocardiography was done 6 months after the diagnosis of PE and RV echocardiographic indices were measured. Pearson correlation was used to investigate correlation between PAOI, PAD, RV strain and signs of right heart dysfunction.

RESULTS

PAOI was strongly correlated with systolic pulmonary artery pressure (SPAP) (r=0.83), RV systolic pressure (r=0.78) and RV wall thickness (r=0.61) in long-term follow up echocardiography. A higher rate of RV dysfunction and RV dilation was detected among the patients with higher PAOI (P<0.001). PAOI≥18 was strongly predictive for development of RV dysfunction. Also developments of pulmonary hypertension, RV systolic hypertension, RV dilation, RV dysfunction, and RV hypertrophy were significantly more common among patients with higher PAD and RV strain (P<0.001).

CONCLUSIONS

PAOI, PAD and RV strain are sensitive and specific PCTA indices that can predict the development of long-term complications such as pulmonary hypertension and right heart dysfunction, at the time of initial PE diagnosis.

Evaluating the Right Ventricle in Acute and Chronic Pulmonary Embolism: Current and Future Considerations

The right ventricle (RV), due to its morphologic and physiologic differences, is susceptible to sudden increase in RV afterload, as noted in patients with acute pulmonary embolism (PE). Functional impairment of RV function is a stronger presage of adverse outcomes in acute PE than the location or burden of emboli. While current iterations of most clinical prognostic scores do not incorporate RV dysfunction, advancements in imaging have enabled more granular and accurate assessment of RV dysfunction in acute PE. RV enlargement and dysfunction on imaging is noted only in a subset of patients with acute PE and is dependent on underlying cardiopulmonary reserve and clot burden. Specific signs like McConnell's and "60/60" sign are noted in less than 20% of patients with acute PE. About 2% of patients with acute PE develop chronic thromboembolic pulmonary hypertension, characterized by continued deterioration in RV function in a subset of patients with a continuum of RV function from preserved to overt right heart failure. Advances in molecular and other imaging will help better characterize RV dysfunction in this population and evaluate the response to therapies.

Imaging of pulmonary hypertension in adults: a position paper from the Fleischner Society

Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mmHg and classified into five different groups sharing similar pathophysiologic mechanisms, haemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was formed from within the Fleischner Society based on expertise in the imaging and/or management of patients with PH, as well as experience with methodologies of systematic reviews. The working group identified key questions focusing on the utility of CT, MRI, and nuclear medicine in the evaluation of PH: a) Is noninvasive imaging capable of identifying PH? b) What is the role of imaging in establishing the cause of PH? c) How does imaging determine the severity and complications of PH? d) How should imaging be used to assess chronic thromboembolic PH before treatment? e) Should imaging be performed after treatment of PH? This systematic review and position paper highlights the key role of imaging in the recognition, work-up, treatment planning, and follow-up of PH.

Imaging of Pulmonary Hypertension in Adults: A Position Paper from the Fleischner Society

Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mm Hg and classified into five different groups sharing similar pathophysiologic mechanisms, hemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was formed from within the Fleischner Society based on expertise in the imaging and/or management of patients with PH, as well as experience with methodologies of systematic reviews. The working group identified key questions focusing on the utility of CT, MRI, and nuclear medicine in the evaluation of PH: (a) Is noninvasive imaging capable of identifying PH? (b) What is the role of imaging in establishing the cause of PH? (c) How does imaging determine the severity and complications of PH? (d) How should imaging be used to assess chronic thromboembolic PH before treatment? (e) Should imaging be performed after treatment of PH? This systematic review and position paper highlights the key role of imaging in the recognition, work-up, treatment planning, and follow-up of PH. This article is a simultaneous joint publication in Radiology and European Respiratory Journal. The articles are identical except for stylistic changes in keeping with each journal's style. Either version may be used in citing this article. © 2021 RSNA and the European Respiratory Society. Online supplemental material is available for this article.

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.

Growth factors in pulmonary arterial hypertension: Focus on preserving right ventricular function

Pulmonary arterial hypertension (PAH) is a rare and progressive disease, characterized by increased vascular resistance leading to right ventricle (RV) failure. The extent of right ventricular dysfunction crucially influences disease prognosis; however, currently no therapies have specific cardioprotective effects. Besides discussing the pathophysiology of right ventricular adaptation in PAH, this review focuses on the roles of growth factors (GFs) in disease pathomechanism. We also summarize the involvement of GFs in the preservation of cardiomyocyte function, to evaluate their potential as cardioprotective biomarkers and novel therapeutic targets in PAH.

Emerging role of cardiovascular magnetic resonance imaging in the management of pulmonary hypertension

Pulmonary hypertension (PH) is a clinical condition characterised by elevation of pulmonary arterial pressure (PAP) above normal range due to various aetiologies. While cardiac right-heart catheterisation (RHC) remains the gold standard and mandatory for establishing the diagnosis of PH, noninvasive imaging of the heart plays a central role in the diagnosis and management of all forms of PH. Although Doppler echocardiography (ECHO) can measure a range of haemodynamic and anatomical variables, it has limited utility for visualisation of the pulmonary artery and, oftentimes, the right ventricle. Cardiovascular magnetic resonance (CMR) provides comprehensive information about the anatomical and functional aspects of the pulmonary artery and right ventricle that are of prognostic significance for assessment of long-term outcomes in disease progression. CMR is suited for serial follow-up of patients with PH due to its noninvasive nature, high sensitivity to changes in anatomical and functional parameters, and high reproducibility. In recent years, there has been growing interest in the use of CMR derived parameters as surrogate endpoints for early-phase PH clinical trials. This review will discuss the role of CMR in the diagnosis and management of PH, including current applications and future developments, in comparison to other existing major imaging modalities.

Effects of pulmonary endarterectomy on pulmonary hemodynamics in chronic thromboembolic pulmonary hypertension, evaluated by interventricular septum curvature

The interventricular septum curvature, measured in images of electrocardiogram-gated 320-slice multidetector computed tomography, is reportedly useful and less invasive than right heart catheterization, as it could provide clues regarding pulmonary arterial pressure in patients with chronic thromboembolic pulmonary hypertension. Although pulmonary endarterectomy is an efficient treatment for chronic thromboembolic pulmonary hypertension, the interventricular septum curvature in patients who have received pulmonary endarterectomy has not been evaluated. We evaluated whether the interventricular septum curvature on electrocardiogram-gated 320-slice multidetector computed tomography can predict pulmonary hemodynamics in chronic thromboembolic pulmonary hypertension even after pulmonary endarterectomy. We studied 40 patients with chronic thromboembolic pulmonary hypertension (60.5 ± 9.7 years; 30 females), who underwent pulmonary endarterectomy at Chiba University Hospital between December 2010 and July 2018. To measure the interventricular septum curvature, we prepared left ventricular short-axis tomographic images from 4D images of electrocardiogram-gated 320-slice multidetector computed tomography. We calculated the radius of interventricular septum and determined the interventricular septum curvature in both the systolic and diastolic phases. We compared the interventricular septum curvature with pulmonary hemodynamics measured by right heart catheterization before and after pulmonary endarterectomy. After pulmonary endarterectomy, the correlations of the interventricular septum curvature with mean pulmonary arterial pressure, systolic pulmonary arterial pressure, and pulmonary vascular resistance disappeared, although the interventricular septum curvature was correlated with these pulmonary hemodynamic parameters before pulmonary endarterectomy. Changes in systolic interventricular septum curvature revealed significant correlations with changes in mean pulmonary arterial pressure, systolic pulmonary arterial pressure and pulmonary vascular resistance. Diastolic interventricular septum curvature also showed significant correlations with preoperative pulmonary hemodynamics, but not with postoperative pulmonary hemodynamics. Changes in the interventricular septum curvature after pulmonary endarterectomy could estimate the efficacy of pulmonary endarterectomy, although the interventricular septum curvature after pulmonary endarterectomy showed no significant correlations with pulmonary hemodynamics. Additionally, our findings confirmed that the interventricular septum curvature before pulmonary endarterectomy could be used to evaluate the severity of disease.

Evaluation of Right Ventricular Function on Cardiac Magnetic Resonance Imaging and Correlation With Hemodynamics in Patients With Chronic Thromboembolic Pulmonary Hypertension

Background: Balloon pulmonary angioplasty (BPA) is an alternative therapy for chronic thromboembolic pulmonary hypertension (CTEPH). Right heart catheterization (RHC) is essential to evaluate the efficacy of BPA. Cardiac magnetic resonance imaging (CMR) is also now used to assess the structure and function of the right heart non-invasively. The aim of this study was to correlate improvement in CMR with that on RHC, and compared with improvement in other non-invasive findings after BPA. Methods and Results: Forty-two patients underwent BPA between July 2012 and March 2015, and CMR, electrocardiography (ECG), and echocardiography were performed at the same time before and 6 months after BPA. Median pulmonary vascular resistance (PVR) was improved from 5.7 Wood units (IQR, 3.1-7.9 Wood units) to 2.7 Wood units (IQR, 1.6-3.9 Wood units; P<0.001). Changes in PVR were correlated with the changes in 5 CMR, 9 ECG, and 5 echocardiography parameters. On logistic analysis to identify the indicators of improving PH (i.e., PVR <3 Wood units), 4 CMR parameters were independently correlated with PVR change, one of which was median septal inversion ratio (SIR; 0.59; IQR, 0.54-0.63 to 0.54; IQR, 0.50-0.58, P<0.0001). SIR was the best predictor of PH (OR, 1.27; P<0.05). Conclusions: CMR can be used to estimate hemodynamic changes after BPA, and SIR is useful to predict alleviation of PH.

Right Ventricular Fibrosis

The role of right ventricular (RV) fibrosis in pulmonary hypertension (PH) remains a subject of ongoing discussion. Alterations of the collagen network of the extracellular matrix may help prevent ventricular dilatation in the pressure-overloaded RV. At the same time, fibrosis impairs cardiac function, and a growing body of experimental data suggests that fibrosis plays a crucial role in the development of RV failure. In idiopathic pulmonary arterial hypertension and chronic thromboembolic PH, the RV is exposed to a ≈5 times increased afterload, which makes these conditions excellent models for studying the impact of pressure overload on RV structure. With this review, we present clinical evidence of RV fibrosis in idiopathic pulmonary arterial hypertension and chronic thromboembolic PH, explore the correlation between fibrosis and RV function, and discuss the clinical relevance of RV fibrosis in patients with PH. We postulate that RV fibrosis has a dual role in patients with pressure-overloaded RVs of idiopathic pulmonary arterial hypertension and chronic thromboembolic PH: as part of an adaptive response to prevent cardiomyocyte overstretch and to maintain RV shape for optimal function, and as part of a maladaptive response that increases diastolic stiffness, perturbs cardiomyocyte excitation-contraction coupling, and disrupts the coordination of myocardial contraction. Finally, we discuss potential novel therapeutic strategies and describe more sensitive techniques to quantify RV fibrosis, which may be used to clarify the causal relation between RV fibrosis and RV function in future research.

The right treatment for the right ventricle

PURPOSE OF REVIEW

Right ventricular (RV) function is an important determinant of morbidity and mortality in patients with pulmonary arterial hypertension (PAH). Although substantial progress has been made in understanding the development of RV failure in the last decennia, this has not yet resulted in the development of RV selective therapies. In this review, we will discuss the current status on the treatment of RV failure and potential novel therapeutic strategies that are currently being investigated in clinical trials.

RECENT FINDINGS

Increased afterload results in elevated wall tension. Consequences of increased wall tension include autonomic disbalance, metabolic shift and inflammation, negatively affecting RV contractility. Compromised RV systolic function and low cardiac output activate renin-angiotensin aldosterone system, which leads to fluid retention and further increase in RV wall tension. This vicious circle can be interrupted by directly targeting the determinants of RV wall tension; preload and afterload by PAH-medications and diuretics, but is also possibly by restoring neurohormonal and metabolic disbalance, and inhibiting maladaptive inflammation. A variety of RV selective drugs are currently being studied in clinical trials.

SUMMARY

Nowadays, afterload reduction is still the cornerstone in treatment of PAH. New treatments targeting important pathobiological determinants of RV failure directly are emerging.

Non-invasive Multimodality Cardiovascular Imaging of the Right Heart and Pulmonary Circulation in Pulmonary Hypertension

Pulmonary hypertension (PH) is defined as resting mean pulmonary arterial pressure (mPAP) ≥25 millimeters of mercury (mmHg) via right heart (RH) catheterization (RHC), where increased afterload in the pulmonary arterial vasculature leads to alterations in RH structure and function. Mortality rates have remained high despite therapy, however non-invasive imaging holds the potential to expedite diagnosis and lead to earlier initiation of treatment, with the hope of improving prognosis. While historically the right ventricle (RV) had been considered a passive chamber with minimal role in the overall function of the heart, in recent years in the evaluation of PH and RH failure the anatomical and functional assessment of the RV has received increased attention regarding its performance and its relationship to other structures in the RH-pulmonary circulation. Today, the RV is the key determinant of patient survival. This review provides an overview and summary of non-invasive imaging methods to assess RV structure, function, flow, and tissue characterization in the setting of imaging's contribution to the diagnostic, severity stratification, prognostic risk, response of treatment management, and disease surveillance implications of PH's impact on RH dysfunction and clinical RH failure.

MRI-derived Regional Biventricular Function in Patients with Chronic Thromboembolic Pulmonary Hypertension Before and After Pulmonary Endarterectomy

RATIONALE AND OBJECTIVES

The aim of this study was to assess regional myocardial function in patients with chronic thromboembolic hypertension (CTEPH) before and after successful pulmonary endarterectomy (PEA) using magnetic resonance imaging.

METHODS

Twenty-two patients with CTEPH underwent cardiac magnetic resonance imaging before and 12 (11, 17) days after PEA. Mean pulmonary artery pressure was evaluated preoperatively by right heart catheterization and during post-PEA intensive care unit-stay using a Swan-Ganz catheter. Biventricular peak systolic longitudinal, radial, circumferential strain and time-to-peak strain were obtained by tissue-tracking analysis.

RESULTS

Mean pulmonary artery pressure decreased (46 mm Hg (34.5, 55) to 24 mm Hg (16, 27); P < .0001) and stroke volume increased (P < .0001) after PEA. In the right ventricle (RV) peak radial strain increased in the anterior (P = .04) and in the inferior wall (P = .0012) and slightly missed statistical significance in the lateral wall (P = .051) and septum (P = .07). Circumferential strain increased in the lateral (P = .0002) and inferior wall of the RV (P = .03) and in the lateral as well as in the inferior wall of the left ventricle (P = .01; P = .03). Radial, longitudinal, and circumferential time-to-peak strain shortened (P < .0001) with resynchronization of the ventricles 12 days after PEA.

CONCLUSION

While biventricular resynchronization and recovery of global predominantly RV function was observed, regional circumferential function mainly improved in the lateral and inferior walls of both ventricles and regional radial function in the RV wall and septum 12 days after PEA, suggesting fibers primarily affected by myocardial stress in patients with CTEPH possibly need a relatively longer recovery time.

[Treatment of chronic thromboembolic pulmonary hypertension in elderly patients]

AIM OF THE STUDY

To establish efficacy and security of invasive treatments for chronic thromboembolic pulmonary hypertension (CTEPH) in elderly patients (≥80 years old): pulmonary endarterectomy (PEA) and balloon pulmonary angioplasty (BPA).

PATIENTS AND METHODS

Between 2014 and 2017, 549 CTEPH patients were addressed to our hospital for PEA (364 patients) or BPA (225). From this total, patients 80 years old and over were: 17 treated by PEA and 21 by BPA. Demographic characteristics as well as hemodynamic parameters, results and complications were compared for both groups (Young - Y - versus Old - O).

RESULTS

Elderly BPA patients presented a higher functional class (mean O: 3,16 versus Y: 2,73; P=0,001), with similar hemodynamics parameters compared with the younger patients. Indication for BPA in the elderly was the presence of comorbidities contraindicating surgery in 33% of cases vs. 9,3% in the younger group (P=0,005). Response to treatment was comparable in both groups with significant reductions of mPAP, PVR and improvement of functional class. Complications rate was alike between groups for hemoptysis, reperfusion lesions or mortality, with the exception of a higher incidence of contrast-induced nephropathy, without need for dialysis, in the elderly group (O: 8,4% versus 2,6%; P=0,010). Elderly PEA patients were more often male (O: 76,5% versus Y: 50,1%; P=0,034) and with a lower creatinine clearance (O: 57,6±13,4 versus Y: 72,2±21,2mL/min/m²; P=0,004). Functional class, hemodynamics, surgical times and in-hospital stay was similar between groups. There is a non-significant trend towards higher in-hospital mortality in the elderly group, CONCLUSIONS: In our experience, treatment of CPC PE in elderly patients, either by PEA or BPA is effective with acceptable complication rates.

Autologous endothelial progenitor cell therapy improves right ventricular function in a model of chronic thromboembolic pulmonary hypertension

BACKGROUND

Right ventricular (RV) failure is the main prognostic factor in pulmonary hypertension, and ventricular capillary density (CD) has been reported to be a marker of RV maladaptive remodeling and failure. Our aim was to determine whether right intracoronary endothelial progenitor cell (EPC) infusion can improve RV function and CD in a piglet model of chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

We compared 3 groups: sham (n = 5), CTEPH (n = 6), and CTEPH with EPC infusion (CTEPH+EPC; n = 5). After EPC isolation from CTEPH+EPC piglet peripheral blood samples at 3 weeks, the CTEPH and sham groups underwent right intracoronary infusion of saline, and the CTEPH+EPC group received EPCs at 6 weeks. RV function, pulmonary hemodynamics, and myocardial morphometry were investigated in the animals at 10 weeks.

RESULTS

After EPC administration, the RV fractional area change increased from 32.75% (interquartile range [IQR], 29.5%-36.5%) to 39% (IQR, 37.25%-46.50%; P = .030). The CTEPH+EPC piglets had reduced cardiomyocyte surface areas (from 298.3 μm² [IQR, 277.4-335.3 μm²] to 234.6 μm² (IQR, 211.1-264.7 μm²; P = .017), and increased CD31 expression (from 3.12 [IQR, 1.27-5.09] to 7.14 [IQR, 5.56-8.41; P = .017). EPCs were found in the RV free wall at 4 and 24 hours after injection but not 4 weeks later.

CONCLUSIONS

Intracoronary infusion of EPC improved RV function and CD in a piglet model of CTEPH. This novel cell-based therapy might represent a promising RV-targeted treatment in patients with pulmonary hypertension.

Treatment strategies for the right heart in pulmonary hypertension

The function of the right ventricle (RV) determines the prognosis of patients with pulmonary hypertension. While much progress has been made in the treatment of pulmonary hypertension, therapies for the RV are less well established. In this review of treatment strategies for the RV, first we focus on ways to reduce wall stress since this is the main determinant of changes to the ventricle. Secondly, we discuss treatment strategies targeting the detrimental consequences of increased RV wall stress. To reduce wall stress, afterload reduction is the essential. Additionally, preload to the ventricle can be reduced by diuretics, by atrial septostomy, and potentially by mechanical ventricular support. Secondary to ventricular wall stress, left-to-right asynchrony, altered myocardial energy metabolism, and neurohumoral activation will occur. These may be targeted by optimising RV contraction with pacing, by iron supplement, by angiogenesis and improving mitochondrial function, and by neurohumoral modulation, respectively. We conclude that several treatment strategies for the right heart are available; however, evidence is still limited and further research is needed before clinical application can be recommended.

Chronic pulmonary embolism: diagnosis

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complication of venous thromboembolic disease. Differently from other causes of pulmonary hypertension, CTEPH is potentially curable with surgery (thromboendarterectomy) or balloon pulmonary angioplasty. Imaging plays a central role in CTEPH diagnosis. The combination of techniques such as lung scintigraphy, computed tomography and magnetic resonance angiography provides non-invasive anatomic and functional information. Conventional pulmonary angiography (CPA) with right heart catheterization (RHC) is considered the gold standard method for diagnosing CTEPH. In this review, we discuss the utility of these imaging techniques in the diagnosis of CTEPH.

Mechanisms of right heart disease in pulmonary hypertension (2017 Grover Conference Series)

Current dogma is that pathological hypertrophy of the right ventricle is a direct consequence of pulmonary vascular remodeling. However, progression of right ventricle dysfunction is not always lung-dependent. Increased afterload caused by pulmonary vascular remodeling initiates the right ventricle hypertrophy, but determinants leading to adaptive or maladaptive hypertrophy and failure remain unknown. Ischemia in a hypertrophic right ventricle may directly contribute to right heart failure. Rapidly enlarging cardiomyocytes switch from aerobic to anaerobic energy generation resulting in cell growth under relatively hypoxic conditions. Cardiac muscle reacts to an increased afterload by over-activation of the sympathetic system and uncoupling and downregulation of β-adrenergic receptors. Recent studies suggest that β blocker therapy in PH is safe, well tolerated, and preserves right ventricle function and cardiac output by reducing right ventricular glycolysis. Fibrosis, an evolutionary conserved process in host defense and wound healing, is dysregulated in maladaptive cardiac tissue contributing directly to right ventricle failure. Despite several mechanisms having been suggested in right heart disease, the causes of maladaptive cardiac remodeling remain unknown and require further research.

Consequences of Venous Thromboembolism, Including Chronic Thromboembolic Pulmonary Hypertension

Venous thromboembolism includes both deep vein thrombosis and pulmonary embolism. They pose a significant risk for morbidity and mortality. In an appropriate clinical setting, invasive interventions, including administration of thrombolytics, anticoagulation, and placement of vena cava filter, are warranted. Bleeding, postthrombotic syndrome, recurrence, and filter-associated complications are few of the complications of this disease. More recently, chronic thromboembolic pulmonary hypertension has gained clinical interest in patients with pulmonary embolism and has warranted close follow-up.

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.

A new CT-score as index of hemodynamic changes in patients with chronic thromboembolic pulmonary hypertension

PURPOSE

The aim of this study was to retrospectively assess the relationship between radiological and hemodynamic parameters in patients with chronic thromboembolic pulmonary hypertension (CTEPH). We introduced a new CT-score to evaluate hemodynamic changes, only employing CT-pulmonary angiography (CTPA).

MATERIALS AND METHODS

145 patients affected by CTEPH underwent hemodynamic and CTPA evaluation. Among these 145 patients, 69 underwent pulmonary endarterectomy (PEA) and performed a CTPA evaluation even after surgery. Hemodynamic assessment considered the values of mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR), obtained through right heart catheterization (RHC). Radiological evaluation included CTPA signs of pulmonary hypertension.

RESULTS

A highly significant statistical correlation was observed between the new CT-score and both mPAP and PVR (p < 0.000) in the whole sample and also in the subgroup who underwent PEA. In addition, mPAP and PVR showed an important association with the severity of mosaic perfusion (p < 0.000). mPAP also correlated with main pulmonary artery diameter (p < 0.01); a significant association was found in both between PVR and tricuspid regurgitation(p < 0.000) and with PVR and presence of unilateral or bilateral pulmonary thromboembolic occlusion (p < 0.05).

CONCLUSION

Our results confirm the diagnostic role of CTPA in evaluating patients with CTEPH and in addition open a new horizon in assessing hemodynamic changes in patients with CTEPH, only employing a CTPA, especially when RHC is contraindicated or not possible.

Pulmonary hypertension

In 2015, more than 800 papers were published in the field of pulmonary hypertension. A Clinical Year in Review article cannot possibly incorporate all this work and needs to be selective. The recently published European guidelines for the diagnosis and treatment of pulmonary hypertension contain an inclusive summary of all published clinical studies conducted until very recently. Here, we provide an overview of papers published after the finalisation of the guideline. In addition, we summarise recent advances in pulmonary vasculature science. The selection we made from the enormous amount of published work undoubtedly reflects our personal views and may not include all papers with a significant impact in the near or more distant future. The focus of this paper is on the diagnosis of pulmonary arterial hypertension, understanding the success of combination therapy on the right ventricle and scientific breakthroughs.

Successful Lung Transplant After Prolonged Extracorporeal Membrane Oxygenation (ECMO) in a Child With Pulmonary Hypertension: A Case Report

INTRODUCTION

The use of extracorporeal membrane oxygenation (ECMO) is considered a risk factor for, or even a potential contraindication to, lung transplantation. However, only a few pediatric cases have been described thus far.

CASE PRESENTATION

A 9-year-old boy with idiopathic pulmonary arterial hypertension developed cardiac arrest after the insertion of a central catheter. ECMO was used as a bridge to lung transplantation. However, after prolonged resuscitation, he developed medullary ischemia and medullary syndrome. After 6 weeks of ECMO and triple combination therapy for pulmonary hypertension, including continuous intravenous prostacyclin, he was weaned off support, and after 2 weeks, bilateral lung transplantation was performed. At 4 years post-transplant, he has minimal problems. The medullary syndrome has also alleviated. He is now back to school and can walk with aids.

CONCLUSIONS

Increasing evidence supports the use of ECMO as a bridge to LT, reporting good outcomes. In the modern era of PAH therapy, it is feasible to use prolonged ECMO support as a bridge to lung transplant, with the aim of weaning off this support; however, its use requires more experience and knowledge of long-term outcomes.

Heart rate response during 6-minute walking testing predicts outcome in operable chronic thromboembolic pulmonary hypertension

BACKGROUND

Six-minute walk test (6MWT) is routinely performed in chronic thromboembolic pulmonary hypertension (CTEPH) before pulmonary endarterectomy (PEA). However, the clinical relevance of heart rate response (ΔHR) and exercise-induced oxygen desaturation (EID) during 6MWT is remaining unknown.

METHODS

Patients undergoing PEA in our center between 03/2013-04/2014 were assessed prospectively with hemodynamic and exercise parameters prior to and 1 year post-PEA. Patients with symptomatic chronic thromboembolic disease (mean pulmonary artery pressure (mPAP) <25 mmHg) and clinical relevant obstructive pulmonary disease were excluded. The following definitions were used: ΔHR = (peak HR - resting HR), percent heart rate reserve (HRR) = (peak HR -rest HR)/(220 - age - rest HR) x 100 and EID = SpO2 ≤88 %.

RESULTS

Thirty-seven patients (of 116 patients screened) with mPAP of 43.2 ± 8.7 mmHg, pulmonary vascular resistance (PVR) of 605.5 ± 228.7 dyn*s/cm(5), cardiac index (CI) of 2.4 ± 0.5 l/min/m(2) and a 6MWT-distance of 404.7 ± 148.4 m and a peak VO2 of 12.3 ± 3.4 ml/min/kg prior to PEA were included. Baseline ΔHR during 6MWT was significantly associated with PVR 1 year post-PEA using linear regression analysis (r = 0.43, p = 0.01). Multivariate analysis indicated an association of HRR during 6MWT and residual PH with a hazard ratio of 1.06 (95 % Confidence interval for hazard ratio 0.99-1.14, p = 0.08). EID was observed commonly during 6MWT but no correlations to outcome parameters were found.

CONCLUSIONS

This is the first prospective study to describe an association of ΔHR during 6MWT with pulmonary hemodynamics 1 year post-PEA. Our preliminary results indicate that HRR derived from 6MWT is of clinical significance. EID was commonly observed, albeit failed as a significant prognostic factor.

Chronic Thromboembolic Pulmonary Hypertension: the End Result of Pulmonary Embolism

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