Ventriculo-arterial coupling detects occult RV dysfunction in chronic thromboembolic pulmonary vascular disease

Can my echo work as a crystal ball? - Echocardiographic parameters predicting residual pulmonary hypertension after pulmonary endarterectomy

INTRODUCTION AND OBJECTIVES

Pulmonary endarterectomy should be considered in all patients with chronic thromboembolic pulmonary hypertension. Twenty five percent of patients maintain pulmonary hypertension after pulmonary endarterectomy, with therapeutic and prognostic implications. We aimed to evaluate echocardiographic parameters at diagnosis as predictors for development of residual pulmonary hypertension.

METHODS

Retrospective, observational, unicentric study of patients with confirmed chronic thromboembolic pulmonary hypertension who underwent pulmonary endarterectomy between January 2010 and October 2024. All patients underwent transthoracic echocardiogram at diagnosis. After pulmonary endarterectomy, patients had a right heart catheterization to exclude residual pulmonary hypertension (mean pulmonary artery pressure ≥30 mmHg). Right heart echocardiographic parameters were assessed and compared.

RESULTS

Thirty-nine patients had chronic thromboembolic pulmonary hypertension and underwent pulmonary endarterectomy during the follow-up period. Mean age at diagnosis was 57.3 years-old. Eighteen patients had documented residual pulmonary hypertension. Tricuspid annular plane systolic excursion (p=0.010), end-diastolic right ventricular area (p<0.001), end-systolic right ventricular area (p<0.001), fractional area change (p=0.006), tricuspid annular plane systolic excursion/pulmonary artery systolic pressure ratio (p=0.002), diastolic (p=0.002) and systolic eccentric ratio (p=0.036) were significantly different between the two groups. End-systolic right ventricular area and end-diastolic right ventricular area were independently associated with residual pulmonary hypertension (p=0.023 and p=0.013), and those with end-diastolic right ventricular area above 27.13 cm2 (area under the curve [AUC] 0.88, sensitivity 89%, specificity 85%, odds ratio 44) and end-systolic right ventricular area >19.54 cm2 (AUC 0.875, sensitivity 88%, specificity 85%, odds ratio 38.5) had higher probability of developing residual pulmonary hypertension after pulmonary endarterectomy.

CONCLUSION

This study shows that certain echocardiographic parameters could be predictors of development of residual pulmonary hypertension after pulmonary endarterectomy; however, validation in larger cohorts is mandatory.

SPARCL1 and NT-proBNP as biomarkers of right ventricular-to-pulmonary artery uncoupling in pulmonary hypertension

AIMS

SPARCL1 was recently identified as a biomarker of right ventricular (RV) maladaptation in patients with pulmonary hypertension (PH), and N-terminal pro-brain natriuretic protein (NT-proBNP) is an established biomarker of RV failure in PH. The present study investigated whether NT-proBNP and SPARCL1 concentrations are associated with load-independent parameters of RV function and RV-to-pulmonary artery (RV-PA) coupling as measured using invasive pressure-volume (PV) loops in the RV.

METHODS

SPARCL1 and NT-proBNP were measured in the plasma of patients with idiopathic pulmonary artery hypertension (IPAH, n = 73). Participants without LV or RV abnormalities served as controls (n = 28). All patients underwent echocardiography and right heart catheterization with invasive PV loop measurements.

RESULTS

Our cohort had more females with IPAH than the control group (64% vs. 35%; P = 0.01) and was older [69 (interquartile range, IQR 57-76) vs. 51 (IQR 35-62) years; P < 0.001]. SPARCL1 and NT-proBNP levels were significantly higher in patients with IPAH as compared with controls (P < 0.0001). Patients with IPAH and maladaptive RV remodelling had higher SPARCL1 and NT-proBNP concentrations than those with adaptive RV remodelling (P < 0.01). Both SPARCL1 and NT-proBNP were good predictors of maladaptive RV remodelling in receiver operating characteristic analysis [area under the curve (AUC) (AUCSPARCL1 = 0.75, AUCNT-proBNP = 0.72, P = 0.36 for AUCSPARCL1 vs. AUCNT-proBNP]. The combined predictive value of SPARCL1 and NT-proBNP (AUC 0.78, P < 0.001) for maladaptive RV was numerically higher than that of either SPARCL1 or NT-proBNP alone (P = 0.16 for AUCSPARCL1 + NT-proBNP vs. AUCNT-proBNP and P = 0.18 for AUCSPARCL1 + NT-proBNP vs. AUCSPARC1). SPARCL1 showed numerically a tendency for a better predictive power than NT-proBNP for parameters of early maladaptive RV remodelling such as RV ejection fraction < 50% (AUCSPARCL1 = 0.77, AUCNT-proBNP = 0.67, P = 0.06 for AUCSPARCL1 vs. AUCNT-proBNP), RV end-diastolic diameter > 42 mm (AUCSPARCL1 = 0.72, AUCNT-proBNP = 0.65, P = 0.19 for AUCSPARCL1 vs. AUCNT-proBNP) and RV end-systolic volume index RVESVI > 31 mL/m2 (AUCSPARCL1 = 0.78, AUCNT-proBNP = 0.71, PP = 0.10 for AUCSPARCL1 vs. AUCNT-proBNP).

CONCLUSIONS

SPARCL1 and NT-proBNP are good predictors of maladaptive RV remodelling and RV-PA uncoupling in IPAH patients. SPARCL1 may be a better predictor of early maladaptive RV remodelling than NT-proBNP.

Cardiopulmonary Exercise Testing With Simultaneous Echocardiography After Pulmonary Embolism

Although current guidelines recommend standard cardiopulmonary exercise testing (CPET) to evaluate symptomatic patients after pulmonary embolism (PE), CPET with simultaneous echocardiography could provide relevant information to evaluate right ventricular-pulmonary arterial coupling. The aim of this study was to investigate exercise-induced changes in echocardiographic variables of RV function or RV- arterial coupling in patients with residual thrombotic defects at 3 months after PE. This retrospective study investigated patients with residual thromboembolic disease on V/Q scintigraphy with persistent symptoms despite adequate anticoagulation after 3 months of acute PE, and resting echocardiography with a low probability of PH. At rest and during exercise, CPET and doppler echocardiography were performed following a standard protocol. Forty-five patients were included, completing a follow-up period of at least 24 months. The mean (standard deviation) age was 63 (15) years, and 24 (53%) patients were male. Four patients developed CTEPH after 2 years follow up. Correlation analyses showed that the peak TAPSE was significantly associated with peak workload (r = 0.454, p = 0.003), peak VO2 (r = 0.558, p < 0.001), VE/VECO2 (AT) (r = -0.531, p < 0.001), and oxygen pulse (r = 0.375, p = 0.02). TAPSE/PASP was only slightly associated with peak workload (r = 0.300, p = 0.045). By contrast, the change on TAPSE (from rest to peak) was significantly correlate with peak oxygen uptake (r = 0.491, p = 0.01). Also, reduced VO2 at AT and TAPSE/PASP was seen in patients with CTEPH. CPET with synchronic echocardiography could be a useful tool in early assessment of symptomatic patients with perfusion defects on imaging after 3 months of correctly treated PE.

Tricuspid annular plane systolic excursion to pulmonary artery systolic pressure ratio in chronic thromboembolic pulmonary hypertension improves with balloon pulmonary angioplasty

Right ventricle (RV)-to-pulmonary artery (PA) coupling measured by the ratio of echocardiography-derived tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP) is a meaningful prognostic marker in pulmonary hypertension (PH). It's unclear if balloon pulmonary angioplasty (BPA) treatment of chronic thromboembolic pulmonary hypertension (CTEPH) alters RV-PA coupling measured by TAPSE/PASP. We reviewed CTEPH patients treated with BPA at our institution who had a transthoracic echocardiogram (TTE) before BPA and a follow-up TTE at any point during BPA. TAPSE was obtained from the initial and lattermost TTE; hemodynamics were obtained before each BPA session. Between March 2015 to October 2023, there were 228 patients treated with BPA. After excluding post-PTE patients and those without PH, 67 were included. Initial TAPSE/PASP was 0.39 ± 0.21 mm/mmHg. Using previously defined TAPSE/PASP tertiles in PH (<0.19, 0.19-0.32, >0.32 mm/mmHg), there were 6 patients (9%) in low, 30 (45%) in middle, and 31 (46%) in the high tertiles at baseline. The lower TAPSE/PASP tertiles had more severe baseline hemodynamics (p < 0.001) compared to the high TAPSE/PASP cohort. At follow-up, TAPSE/PASP improved to 0.47 ± 0.20 mm/mmHg (p = 0.023), with 2 (3%), 13 (19%), and 52 (78%) patients in the low, middle, high TAPSE/PASP tertiles, respectively. As patients progress through BPA sessions, the TAPSE/PASP ratio increases, possibly reflecting improved RV mechanics and RV-PA coupling. TAPSE/PASP ratio as a marker of RV-PA coupling can improve with BPA treatment and may be an important measure to follow during treatment of CTEPH.

Right Ventricle-Pulmonary Artery Coupling in Patients Undergoing Cardiac Interventions

PURPOSE OF REVIEW

This review aims to summarize the fundamentals of RV-PA coupling, its non-invasive means of measurement, and contemporary understanding of RV-PA coupling in cardiac surgery, cardiac interventions, and congenital heart disease.

RECENT FINDINGS

The need for more accessible clinical means of evaluation of RV-PA coupling has driven researchers to investigate surrogates using cardiac MRI, echocardiography, and right-sided pressure measurements in patients undergoing cardiac surgery/interventions, as well as patients with congenital heart disease. Recent research has aimed to validate these alternative means against the gold standard, as well as establish cut-off values predictive of morbidity and/or mortality. This emerging evidence lays the groundwork for identifying appropriate RV-PA coupling surrogates and integrating them into perioperative clinical practice.

Exercise Testing in the Risk Assessment of Pulmonary Hypertension

TOPIC IMPORTANCE

Right ventricular dysfunction in pulmonary hypertension (PH) contributes to reduced exercise capacity, morbidity, and mortality. Exercise can unmask right ventricular dysfunction not apparent at rest, with negative implications for prognosis.

REVIEW FINDINGS

Among patients with pulmonary vascular disease, right ventricular afterload may increase during exercise out of proportion to increases observed among healthy individuals. Right ventricular contractility must increase to match the demands of increased afterload to maintain ventricular-arterial coupling (the relationship between contractility and afterload) and ultimately cardiac output. Impaired right ventricular contractile reserve leads to ventricular-arterial uncoupling, preventing cardiac output from increasing during exercise and limiting exercise capacity. Abnormal pulmonary vascular response to exercise can signify early pulmonary vascular disease and is associated with increased mortality. Impaired right ventricular contractile reserve similarly predicts poor outcomes, including reduced exercise capacity and death. Exercise provocation can be used to assess pulmonary vascular response to exercise and right ventricular contractile reserve. Noninvasive techniques (including cardiopulmonary exercise testing, transthoracic echocardiography, and cardiac MRI) as well as invasive techniques (including right heart catheterization and pressure-volume analysis) may be applied selectively to the screening, diagnosis, and risk stratification of patients with suspected or established PH. Further research is required to determine the role of exercise stress testing in the management of pulmonary vascular disease.

SUMMARY

This review describes the current understanding of clinical applications of exercise testing in the risk assessment of patients with suspected or established PH.

Pathophysiology of the right ventricle in health and disease: an update

The contribution of the right ventricle (RV) to cardiac output is negligible in normal resting conditions when pressures in the pulmonary circulation are low. However, the RV becomes relevant in healthy subjects during exercise and definitely so in patients with increased pulmonary artery pressures both at rest and during exercise. The adaptation of RV function to loading rests basically on an increased contractility. This is assessed by RV end-systolic elastance (Ees) to match afterload assessed by arterial elastance (Ea). The system has reserve as the Ees/Ea ratio or its imaging surrogate ejection fraction has to decrease by more than half, before the RV undergoes an increase in dimensions with eventual increase in filling pressures and systemic congestion. RV-arterial uncoupling is accompanied by an increase in diastolic elastance. Measurements of RV systolic function but also of diastolic function predict outcome in any cause pulmonary hypertension and heart failure with or without preserved left ventricular ejection fraction. Pathobiological changes in the overloaded RV include a combination of myocardial fibre hypertrophy, fibrosis and capillary rarefaction, a titin phosphorylation-related displacement of myofibril tension-length relationships to higher pressures, a metabolic shift from mitochondrial free fatty acid oxidation to cytoplasmic glycolysis, toxic lipid accumulation, and activation of apoptotic and inflammatory signalling pathways. Treatment of RV failure rests on the relief of excessive loading.

Adaptive versus maladaptive right ventricular remodelling

Right ventricular (RV) function and its adaptation to increased afterload [RV-pulmonary arterial (PA) coupling] are crucial in various types of pulmonary hypertension, determining symptomatology and outcome. In the course of disease progression and increasing afterload, the right ventricle undergoes adaptive remodelling to maintain right-sided cardiac output by increasing contractility. Exhaustion of compensatory RV remodelling (RV-PA uncoupling) finally leads to maladaptation and increase of cardiac volumes, resulting in heart failure. The gold-standard measurement of RV-PA coupling is the ratio of contractility [end-systolic elastance (Ees)] to afterload [arterial elastance (Ea)] derived from RV pressure-volume loops obtained by conductance catheterization. The optimal Ees/Ea ratio is between 1.5 and 2.0. RV-PA coupling in pulmonary hypertension has considerable reserve; the Ees/Ea threshold at which uncoupling occurs is estimated to be ~0.7. As RV conductance catheterization is invasive, complex, and not widely available, multiple non-invasive echocardiographic surrogates for Ees/Ea have been investigated. One of the first described and best validated surrogates is the ratio of tricuspid annular plane systolic excursion to estimated pulmonary arterial systolic pressure (TAPSE/PASP), which has shown prognostic relevance in left-sided heart failure and precapillary pulmonary hypertension. Other RV-PA coupling surrogates have been formed by replacing TAPSE with different echocardiographic measures of RV contractility, such as peak systolic tissue velocity of the lateral tricuspid annulus (S'), RV fractional area change, speckle tracking-based RV free wall longitudinal strain and global longitudinal strain, and three-dimensional RV ejection fraction. PASP-independent surrogates have also been studied, including the ratios S'/RV end-systolic area index, RV area change/RV end-systolic area, and stroke volume/end-systolic volume. Limitations of these non-invasive surrogates include the influence of severe tricuspid regurgitation (which can cause distortion of longitudinal measurements and underestimation of PASP) and the angle dependence of TAPSE and PASP. Detection of early RV remodelling may require isolated analysis of single components of RV shortening along the radial and anteroposterior axes as well as the longitudinal axis. Multiple non-invasive methods may need to be applied depending on the level of RV dysfunction. This review explains the mechanisms of RV (mal)adaptation to its load, describes the invasive assessment of RV-PA coupling, and provides an overview of studies of non-invasive surrogate parameters, highlighting recently published works in this field. Further large-scale prospective studies including gold-standard validation are needed, as most studies to date had a retrospective, single-centre design with a small number of participants, and validation against gold-standard Ees/Ea was rarely performed.

Right ventricular-pulmonary artery coupling in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension occurs in a proportion of patients with prior acute pulmonary embolism and is characterised by breathlessness, persistently raised pulmonary pressures and right heart failure. Surgical pulmonary endarterectomy (PEA) offers significant prognostic and symptomatic benefits for patients with proximal disease distribution. For those with inoperable disease, management options include balloon pulmonary angioplasty (BPA) and medical therapy. Current clinical practice relies on the evaluation of pulmonary haemodynamics to assess disease severity, timing of and response to treatment. However, pulmonary haemodynamics correlate poorly with patient symptoms, which are influenced by right ventricular tolerance of the increased afterload. How best to manage symptomatic patients with chronic thromboembolic pulmonary disease (CTEPD) in the absence of pulmonary hypertension is not resolved.Right ventricular-pulmonary artery coupling (RV-PAC) describes the energy transfer within the whole cardiopulmonary unit. Thus, it can identify the earliest signs of decompensation even before pulmonary hypertension is overt. Invasive measurement of coupling using pressure volume loop technology is well established in research settings. The development of efficient and less invasive measurement methods has revived interest in coupling as a viable clinical tool. Significant improvement in RV-PAC has been demonstrated after both PEA and BPA. Further studies are required to understand its clinical utility and prognostic value, in particular, its potential to guide management in patients with CTEPD. Finally, given the reported differences in coupling between sexes in pulmonary arterial hypertension, further work is required to understand the applicability of proposed thresholds for decoupling in therapeutic decision making.

Why are bleeding trauma patients still dying? Towards a systems hypothesis of trauma

Over the years, many explanations have been put forward to explain early and late deaths following hemorrhagic trauma. Most include single-event, sequential contributions from sympathetic hyperactivity, endotheliopathy, trauma-induced coagulopathy (TIC), hyperinflammation, immune dysfunction, ATP deficit and multiple organ failure (MOF). We view early and late deaths as a systems failure, not as a series of manifestations that occur over time. The traditional approach appears to be a by-product of last century's highly reductionist, single-nodal thinking, which also extends to patient management, drug treatment and drug design. Current practices appear to focus more on alleviating symptoms rather than addressing the underlying problem. In this review, we discuss the importance of the system, and focus on the brain's "privilege" status to control secondary injury processes. Loss of status from blood brain barrier damage may be responsible for poor outcomes. We present a unified Systems Hypothesis Of Trauma (SHOT) which involves: 1) CNS-cardiovascular coupling, 2) Endothelial-glycocalyx health, and 3) Mitochondrial integrity. If central control of cardiovascular coupling is maintained, we hypothesize that the endothelium will be protected, mitochondrial energetics will be maintained, and immune dysregulation, inflammation, TIC and MOF will be minimized. Another overlooked contributor to early and late deaths following hemorrhagic trauma is from the trauma of emergent surgery itself. This adds further stress to central control of secondary injury processes. New point-of-care drug therapies are required to switch the body's genomic and proteomic programs from an injury phenotype to a survival phenotype. Currently, no drug therapy exists that targets the whole system following major trauma.

Update on balloon pulmonary angioplasty for treatment of chronic thromboembolic pulmonary hypertension

PURPOSE OF REVIEW

To provide an update on balloon pulmonary angioplasty (BPA) for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH), a pulmonary vascular disease that is characterized by fibro-thrombotic material mechanically obliterating major pulmonary arteries, resulting in increased pulmonary vascular resistance (PVR), progressive pulmonary hypertension (PH) combined with a microscopic pulmonary vasculopathy [1▪▪], right ventricular (RV) failure [2] and premature death.

RECENT FINDINGS

Data from a most recent CTEPH European registry (2015 and 2016) suggest significantly improved survival [3▪] of CTEPH patients compared with survival in the eighties [4], or with data from 2007 and 2009 [5]. Pulmonary endarterectomy (PEA) is still the gold-standard therapy for CTEPH [6,7]. However, only around two thirds of all CTEPH patients are amenable to surgery [3▪,5]. Patients not suitable for PEA and treated conservatively have a poor prognosis [8]. BPA may have a role for this particular group of patients. [9-11]. Currently, BPA programs are available in many countries, with excellent results at expert centers [12-15,16▪,17,18▪▪]. Based on recent data, BPA seems to have a greater impact on symptomatic and hemodynamic improvement than medical therapy with riociguat alone [15].

SUMMARY

The evidence favoring BPA is growing, but there is still a lack of published controlled trials. In addition, treatment concepts including indication, technical performance, use of PH-targeted medication, and the concept of follow-up vary between centers. In addition, there is a significant learning curve impacting outcomes [13]. The data from the International BPA registry will provide answers for some of the open questions.

Prognostic implication of noninvasive right ventricle-to-pulmonary artery coupling in chronic thromboembolic pulmonary hypertension

Aims:

Impairment of right ventricle-to-pulmonary artery coupling (RV-PA coupling) is a major determinant of poor prognosis in patients with pulmonary hypertension. This study sought to evaluate the ability of an echo-derived metric of RV-PA coupling, the ratio between tricuspid annular plane systolic excursion (TAPSE), and pulmonary artery systolic pressure (PASP) and to predict adverse clinical outcomes in chronic thromboembolic pulmonary hypertension (CTEPH).

Methods and results:

A total of 205 consecutive patients with confirmed CTEPH were retrospectively recruited from Fuwai Hospital between February 2016 and November 2020. Baseline echocardiography, right heart catheterization, and cardiopulmonary exercise testing were analyzed. Patients with lower TAPSE/PASP had a significantly compromised echocardiographic and hemodynamic status and exercise capacity at baseline. The TAPSE/PASP ratio correlated significantly with hemodynamic parameters, including pulmonary vascular resistance (r = −0.48, p < 0.001) and pulmonary arterial compliance (r = 0.45, p < 0.001). During a median period of 1-year follow-up, 63 (30.7%) patients experienced clinical worsening. The relationship between TAPSE/PASP and clinical worsening was assessed using different multivariate Cox regression models. After adjustment for a series of previously screened independent predictors, TAPSE/PASP remained significantly associated with outcomes, and the hazard ratio (per standard deviation increase) of the final model was 0.402.

Conclusion:

In patients with CTEPH, baseline RV-PA coupling measured as the TAPSE/PASP ratio is associated with disease severity and adverse outcomes. A low TAPSE/PASP identifies patients with a high risk of clinical deterioration, and this novel metric could be applicable for risk stratification in CTEPH.

Effects of Mechanical Ventilation Versus Apnea on Bi-Ventricular Pressure-Volume Loop Recording

Respiration changes intrathoracic pressure and lung volumes in a cyclic manner, which affect cardiac function. Invasive ventricular pressure-volume (PV) loops can be recorded during ongoing mechanical ventilation or in transient apnea. No consensus exists considering ventilatory mode during PV loop recording. The objective of this study was to investigate the magnitude of any systematic difference of bi-ventricular PV loop variables recorded during mechanical ventilation versus apnea. PV loops were recorded simultaneously from the right ventricle and left ventricle in a closed chest porcine model during mechanical ventilation and in transient apnea (n=72). Variables were compared by regression analyses. Mechanical ventilation versus apnea affected regression coefficients for important PV variables including right ventricular stroke volume (1.22, 95% CI [1.08-1.36], p=0.003), right ventricular ejection fraction (0.90, 95% CI [0.81-1.00], p=0.043) and right ventricular arterial elastance (0.61, 95%CI [0.55-0.68], p<0.0001). Right ventricular pressures and volumes were parallelly shifted with Y-intercepts different from 0. Few left ventricular variables were affected, mainly first derivatives of pressure (dP/dt(max): 0.96, 95% CI [0.92-0.99], p=0.016, and dP/dt(min): 0.92, 95% CI [0.86-0.99], p=0.026), which might be due to decreased heart rate in apnea (Y-intercept -6.88, 95% CI [-12.22; -1.54], p=0.012). We conclude, that right ventricular stroke volume, ejection fraction and arterial elastance were mostly affected by apnea compared to mechanical ventilation. The results motivate future standardization of respiratory modality when measuring PV relationships.

Serial right heart catheter assessment between balloon pulmonary angioplasty sessions identify procedural factors that influence response to treatment

BACKGROUND

Balloon pulmonary angioplasty (BPA) is delivered as a series of treatments for patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) however, there is little published data on the procedural determinants of outcome.

METHODS

Pre- and post-BPA clinical and hemodynamic data, as well as serial hemodynamic and procedural data at each BPA session were evaluated to determine patient and procedure-related factors that influence hemodynamic response.

RESULTS

Per procedure data from 210 procedures in 84 patients and per patient data from 182 procedures in 63 patients with completed treatment and 3-month follow-up were analyzed. A median of 3 (range 1-6) BPA procedures treating a median of 2 segments per procedure (range 1-3) were performed per patient with a median interval between procedures of 42 (range 5-491) days. Clinical outcome correlated with hemodynamic change (pulmonary vascular resistance [ΔPVR] vs Cambridge Pulmonary Hypertension Outcome Review [CAMPHOR] symptom score: p < 0.001, Pearson's r = 0.48, n = 49). Responders to BPA had more severe disease at baseline and 37.5 % of non-responders were post-PEA. There was a dose-response relationship between per procedure and total number of segments treated and hemodynamic improvement (ΔPVR: 1 segment: -0.9%, 2: -14.5%, 3 or more: -16.1%, p < 0.001). Treating totally occluded vessels had a greater hemodynamic effect (mean pulmonary artery pressure [ΔmPAP]: sessions with occlusion: -8.0%, without occlusion treated: -3.2%, p < 0.05) without an increased complication rate.

CONCLUSIONS

The magnitude of clinical benefit is related to the hemodynamic effect of BPA which in turn is related to the number of segments treated and lesion severity. Patients who were post-PEA were less likely to respond to BPA.

ERS statement on chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication of acute pulmonary embolism, either symptomatic or not. The occlusion of proximal pulmonary arteries by fibrotic intravascular material, in combination with a secondary microvasculopathy of vessels <500 µm, leads to increased pulmonary vascular resistance and progressive right heart failure. The mechanism responsible for the transformation of red clots into fibrotic material remnants has not yet been elucidated. In patients with pulmonary hypertension, the diagnosis is suspected when a ventilation/perfusion lung scan shows mismatched perfusion defects, and confirmed by right heart catheterisation and vascular imaging. Today, in addition to lifelong anticoagulation, treatment modalities include surgery, angioplasty and medical treatment according to the localisation and characteristics of the lesions.This statement outlines a review of the literature and current practice concerning diagnosis and management of CTEPH. It covers the definitions, diagnosis, epidemiology, follow-up after acute pulmonary embolism, pathophysiology, treatment by pulmonary endarterectomy, balloon pulmonary angioplasty, drugs and their combination, rehabilitation and new lines of research in CTEPH.It represents the first collaboration of the European Respiratory Society, the International CTEPH Association and the European Reference Network-Lung in the pulmonary hypertension domain. The statement summarises current knowledge, but does not make formal recommendations for clinical practice.

Predictors and prognosis of right ventricular function in pulmonary hypertension due to heart failure with reduced ejection fraction

Aims

Failure of right ventricular (RV) function worsens outcome in pulmonary hypertension (PH). The adaptation of RV contractility to afterload, the RV‐pulmonary artery (PA) coupling, is defined by the ratio of RV end‐systolic to PA elastances (Ees/Ea). Using pressure–volume loop (PV‐L) technique we aimed to identify an Ees/Ea cut‐off predictive for overall survival and to assess hemodynamic and morphologic conditions for adapted RV function in secondary PH due to heart failure with reduced ejection fraction (HFREF).

Methods and results

This post hoc analysis is based on 112 patients of the prospective Magdeburger Resynchronization Responder Trial. All patients underwent right and left heart echocardiography and a baseline PV‐L and RV catheter measurement. A subgroup of patients (n = 50) without a pre‐implanted cardiac device underwent magnetic resonance imaging at baseline. The analysis revealed that 0.68 is an optimal Ees/Ea cut‐off (area under the curve: 0.697, P < 0.001) predictive for overall survival (median follow up = 4.7 years, Ees/Ea ≥ 0.68 vs. <0.68, log‐rank 8.9, P = 0.003). In patients with PH (n = 76, 68%) multivariate Cox regression demonstrated the independent prognostic value of RV‐Ees/Ea in PH patients (hazard ratio 0.2, P < 0.038). Patients without PH (n = 36, 32%) and those with PH but RV‐Ees/Ea ≥ 0.68 showed comparable RV‐Ees/Ea ratios (0.88 vs. 0.9, P = 0.39), RV size/function, and survival. In contrast, secondary PH with RV‐PA coupling ratio Ees/Ea < 0.68 corresponded extremely close to cut‐off values that define RV dilatation/remodelling (RV end‐diastolic volume >160 mL, RV‐mass/volume‐ratio ≤0.37 g/mL) and dysfunction (right ventricular ejection fraction <38%, tricuspid annular plane systolic excursion <16 mm, fractional area change <42%, and stroke‐volume/end‐systolic volume ratio <0.59) and is associated with a dramatically increased short and medium‐term all‐cause mortality. Independent predictors of prognostically unfavourable RV‐PA coupling (Ees/Ea < 0.68) in secondary PH were a pre‐existent dilated RV [end‐diastolic volume >171 mL, odds ratio (OR) 0.96, P = 0.021], high pulsatile load (PA compliance <2.3 mL/mmHg, OR 8.6, P = 0.003), and advanced systolic left heart failure (left ventricular ejection fraction <30%, OR 1.23, P = 0.028).

Conclusions

The RV‐PA coupling ratio Ees/Ea predicts overall survival in PH due to HFREF and is mainly affected by pulsatile load, RV remodelling, and left ventricular dysfunction. Prognostically favourable coupling (RV‐Ees/Ea ≥ 0.68) in PH was associated with preserved RV size/function and mid‐term survival, comparable with HFREF without PH.

Chronic Thromboembolic Pulmonary Hypertension - What Have We Learned From Large Animal Models

Chronic thrombo-embolic pulmonary hypertension (CTEPH) develops in a subset of patients after acute pulmonary embolism. In CTEPH, pulmonary vascular resistance, which is initially elevated due to the obstructions in the larger pulmonary arteries, is further increased by pulmonary microvascular remodeling. The increased afterload of the right ventricle (RV) leads to RV dilation and hypertrophy. This RV remodeling predisposes to arrhythmogenesis and RV failure. Yet, mechanisms involved in pulmonary microvascular remodeling, processes underlying the RV structural and functional adaptability in CTEPH as well as determinants of the susceptibility to arrhythmias such as atrial fibrillation in the context of CTEPH remain incompletely understood. Several large animal models with critical clinical features of human CTEPH and subsequent RV remodeling have relatively recently been developed in swine, sheep, and dogs. In this review we will discuss the current knowledge on the processes underlying development and progression of CTEPH, and on how animal models can help enlarge understanding of these processes.

Trauma of major surgery: A global problem that is not going away

Globally, a staggering 310 million major surgeries are performed each year; around 40 to 50 million in USA and 20 million in Europe. It is estimated that 1-4% of these patients will die, up to 15% will have serious postoperative morbidity, and 5-15% will be readmitted within 30 days. An annual global mortality of around 8 million patients places major surgery comparable with the leading causes of death from cardiovascular disease and stroke, cancer and injury. If surgical complications were classified as a pandemic, like HIV/AIDS or coronavirus (COVID-19), developed countries would work together and devise an immediate action plan and allocate resources to address it. Seeking to reduce preventable deaths and post-surgical complications would save billions of dollars in healthcare costs. Part of the global problem resides in differences in institutional practice patterns in high- and low-income countries, and part from a lack of effective perioperative drug therapies to protect the patient from surgical stress. We briefly review the history of surgical stress and provide a path forward from a systems-based approach. Key to progress is recognizing that the anesthetized brain is still physiologically 'awake' and responsive to the sterile stressors of surgery. New intravenous drug therapies are urgently required after anesthesia and before the first incision to prevent the brain from switching to sympathetic overdrive and activating secondary injury progression such as hyperinflammation, coagulopathy, immune activation and metabolic dysfunction. A systems-based approach targeting central nervous system-mitochondrial coupling may help drive research to improve outcomes following major surgery in civilian and military medicine.

The left atrium and the right ventricle: two supporting chambers to the failing left ventricle

Heart failure (HF) is mainly caused by left ventricular (LV) impairment of function, hence detailed assessment of its structure and function is a clinical priority. The frequent involvement of the left atrium (LA) and the right ventricle (RV) in the overall cardiac performance has recently gained significant interest with specific markers predicting exercise intolerance and prognosis being proposed. The LA and RV are not anatomically separated from the LV, while the LA controls the inlet the RV shares the interventricular septum with the LV. Likewise, the function of the two chambers is not entirely independent from that of the LV, with the LA enlarging to accommodate any rise in filling pressures, which could get transferred to the RV via the pulmonary circulation. In the absence of pulmonary disease, LA and RV function may become impaired in patients with moderate-severe LV disease and raised filling pressures. These changes can often occur irrespective of the severity of systolic dysfunction, thus highlighting the important need for critical assessment of the function of the two chambers. This review evaluates the pivotal role of the left atrium and right ventricle in the management of HF patients based on the available evidence.

Right heart failure in pulmonary hypertension: Diagnosis and new perspectives on vascular and direct right ventricular treatment

Adaptation of right ventricular (RV) function to increased afterload-known as RV-arterial coupling-is a key determinant of prognosis in pulmonary hypertension. However, measurement of RV-arterial coupling is a complex, invasive process involving analysis of the RV pressure-volume relationship during preload reduction over multiple cardiac cycles. Simplified methods have therefore been proposed, including echocardiographic and cardiac MRI approaches. This review describes the available methods for assessment of RV function and RV-arterial coupling and the effects of pharmacotherapy on these variables. Overall, pharmacotherapies for pulmonary hypertension have shown beneficial effects on various measures of RV function, but it is often unclear if these are direct RV effects or indirect results of afterload reduction. Studies of the effects of pharmacotherapies on RV-arterial coupling are limited and mostly restricted to experimental models. Simplified methods to assess RV-arterial coupling should be validated and incorporated into routine clinical follow-up and future clinical trials. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.1/issuetoc.

Pressure Volume System for Management of Heart Failure and Valvular Heart Disease

PURPOSE OF REVIEW

To introduce the reader to the basics of pressure-volume (PV) analysis, its current role in management of heart failure and valvular disease, and the possibilities for future use.

RECENT FINDINGS

The recent introduction of FDA-approved miniaturized conductance catheters that can produce PV loops in the clinical setting has set the stage for the translation of this important research technique into clinical practice. The use of these catheters has shed important insights into the pathophysiology of many common conditions associated with heart failure including heart failure with preserved ejection fraction and right heart failure and has been utilized to assist in optimization of lead placement during cardiac resynchronization therapy. The use of PV loops has enhanced our understanding and diagnosis of common conditions associated with heart failure. In addition, it has shown promise as an adjunct to therapeutic procedures. Future directions may include the use of PV loops in the management of patients with heart failure requiring mechanical circulatory support and to help predict the utility of percutaneous valvular interventions.

Right ventricular function in pulmonary (arterial) hypertension

The right ventricle (RV) is the main determinant of prognosis in pulmonary hypertension. Adaptation and maladaptation of the RV are of crucial importance. In the course of disease, RV contractility increases through changes in muscle properties and muscle hypertrophy. At a certain point, the point of "uncoupling," the afterload exceeds contractility, and maladaptation as well as dilation occurs to maintain stroke volume (SV). To understand the adaptational processes and to further develop targeted medication directly affecting load-independent contractility, an accurate and precise assessment of contractility and RV-pulmonary artery (PA) coupling should be performed. In this review, we shed light on existing methods to assess RV function, including the gold standard measurement of contractility and RV-PA coupling, and we evaluate existing surrogates of RV-PA coupling.

The importance of right ventricular function in patients with pulmonary arterial hypertension

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a progressive, life-threatening, and incurable disease. Its prognosis is based on right ventricular (RV) function. Therefore, adequate assessment of RV function is mandatory. Areas covered: This article presents the case of a patient with PAH in which the traditional diagnostic approach did not provide a complete assessment of RV function. The authors show how the analysis of other parameters yielded additional information that improved the management of this patient. Expert commentary: Despite current treatments, PAH often worsens due to progressive RV dysfunction. Appropriate assessment of RV function may facilitate the early identification of patients at risk of RV function impairment. More aggressive treatment of PAH might delay progression of the disease. Traditional risk stratification, which is based on New York Heart Association/World Health Organization (NYHA/WHO) functional class evaluation, the 6-minute walk test, and right heart catheterization, proves insufficient in many PAH patients, as it does not provide complete information about RV function. Thus, further parameters are required. Analysis of RV function, in addition to echocardiography and cardiopulmonary exercise testing, may add relevant prognostic information and improve therapy.

Three-Dimensional Echocardiography for the Assessment of Right Ventriculo-Arterial Coupling

BACKGROUND

The analysis of right ventriculo-arterial coupling (RVAC) from pressure-volume loops is not routinely performed. RVAC may be approached by the combination of right heart catheterization (RHC) pressure data and cardiac magnetic resonance (CMR)-derived right ventricular (RV) volumetric data. RV pressure and volume measurements by Doppler and three-dimensional echocardiography (3DE) allows another way to approach RVAC.

METHODS

Ninety patients suspected of having pulmonary hypertension underwent RHC, 3DE, and CMR (RHC mean pulmonary artery pressure [mPAP] 37.9 ± 11.3 mm Hg; range, 15-66 mm Hg). Three-dimensional (3D) echocardiography was performed in 30 normal patients (echocardiographic mPAP 18.4 ± 3.1 mm Hg). Pulmonary artery (PA) effective elastance (Ea), RV maximal end-systolic elastance (Emax), and RVAC (PA Ea/RV Emax) were calculated from RHC combined with CMR and from 3DE using simplified formulas including mPAP, stroke volume, and end-systolic volume.

RESULTS

Three-dimensional echocardiographic and RHC-CMR measures for PA Ea (3DE, 1.27 ± 0.94; RHC-CMR, 0.71 ± 0.52; r = 0.806, P < .001), RV Emax (3DE, 0.72 ± 0.37; RHC-CMR, 0.38 ± 0.19; r = 0.798, P < .001), and RVAC (3DE, 2.01 ± 1.28; RHC-CMR, 2.32 ± 1.77; r = 0.826, P < .001) were well correlated despite a systematic overestimation of 3DE elastance parameters. Among the whole population, 3D echocardiographic PA Ea and 3D echocardiographic RVAC but not 3D echocardiographic RV Emax were significantly lower in patients with mPAP < 25 mm Hg (n = 41) than in others (n = 79). Among the 90 patients who underwent RHC, 3D echocardiographic PA Ea and 3D echocardiographic RVAC but not 3D echocardiographic RV Emax increased significantly with increasing levels of pulmonary vascular resistance.

CONCLUSIONS

Three-dimensional echocardiography-derived PA Ea, RV Emax, and RVAC correlated well with the reference RHC-CMR measurements. Ea and RVAC but not Emax were significantly different between patients with different levels of afterload, suggesting failure of the right ventricle to maintain coupling in severe pulmonary hypertension.

Ventriculo-arterial coupling detects occult RV dysfunction in chronic thromboembolic pulmonary vascular disease

Chronic thromboembolic disease (CTED) is suboptimally defined by a mean pulmonary artery pressure (mPAP) <25 mmHg at rest in patients that remain symptomatic from chronic pulmonary artery thrombi. To improve identification of right ventricular (RV) pathology in patients with thromboembolic obstruction, we hypothesized that the RV ventriculo-arterial (Ees/Ea) coupling ratio at maximal stroke work (Ees/Ea_{max sw}) derived from an animal model of pulmonary obstruction may be used to identify occult RV dysfunction (low Ees/Ea) or residual RV energetic reserve (high Ees/Ea). Eighteen open chested pigs had conductance catheter RV pressure-volume (PV)-loops recorded during PA snare to determine Ees/Ea_{max sw} This was then applied to 10 patients with chronic thromboembolic pulmonary hypertension (CTEPH) and ten patients with CTED, also assessed by RV conductance catheter and cardiopulmonary exercise testing. All patients were then restratified by Ees/Ea. The animal model determined an Ees/Ea_{max sw} = 0.68 ± 0.23 threshold, either side of which cardiac output and RV stroke work fell. Two patients with CTED were identified with an Ees/Ea well below 0.68 suggesting occult RV dysfunction whilst three patients with CTEPH demonstrated Ees/Ea ≥ 0.68 suggesting residual RV energetic reserve. Ees/Ea > 0.68 and Ees/Ea < 0.68 subgroups demonstrated constant RV stroke work but lower stroke volume (87.7 ± 22.1 vs. 60.1 ± 16.3 mL respectively, P = 0.006) and higher end-systolic pressure (36.7 ± 11.6 vs. 68.1 ± 16.7 mmHg respectively, P < 0.001). Lower Ees/Ea in CTED also correlated with reduced exercise ventilatory efficiency. Low Ees/Ea aligns with features of RV maladaptation in CTED both at rest and on exercise. Characterization of Ees/Ea in CTED may allow for better identification of occult RV dysfunction.