Evaluation and Prognostic Relevance of Right Ventricular-Arterial Coupling in Pulmonary Hypertension

Right ventricular dysfunction: pathophysiology, experimental models, evaluation, and treatment

Interest in the right ventricle has substantially increased due to advances in knowledge of its pathophysiology and prognostic implications across a wide spectrum of diseases. However, we are still far from understanding the multiple mechanisms that influence right ventricular dysfunction, its evaluation continues to be challenging, and there is a shortage of specific treatments in most scenarios. This review article aims to update knowledge about the physiology of the right ventricle, its transition to dysfunction, diagnostic tools, and available treatments from a translational perspective.

An interactive dose optimizer based on population pharmacokinetic study to guide dosing of methotrexate in Chinese patients with osteosarcoma

PURPOSE

Osteosarcoma is a rare tumor with an incidence of 4.4 cases per million per year in adolescent. High-dose methotrexate (HD-MTX) is the standard first-line chemotherapeutic agent for osteosarcoma. However, its efficacy can vary significantly among individuals due to wide pharmacokinetic variability. Despite this, only a few population pharmacokinetics (popPK) models based on Chinese patients with osteosarcoma have been reported. Thus, this study aimed to develop a HD-MTX popPK model and an individual model-based dose optimizer for osteosarcoma therapy.

METHOD

A total of 680 MTX serum concentrations from 57 patients with osteosarcoma were measured at the end of MTX infusion and 10 h, 24 h, 48 h, and 72 h after the start of infusion. Using the first-order conditional estimation method with NONMEM, a popPK model was estimated. Goodness-of-fit plots, visual predictive checks, and bootstrap analysis were generated to evaluate the final model. A dose optimizer tool was developed based on the validated models using R Shiny. Additionally, clinical data from 12 patients with newly diagnosed osteosarcoma were collected and used as the validation set to preliminarily verify the predictive ability of the popPK model and the dose optimizer tool.

RESULTS

Body surface area (BSA) was the most significant covariate for compartment distribution. Creatinine clearance (CrCL) and co-administration of NSAIDs were introduced as predictors for central compartmental and peripheral compartmental clearance, respectively. Co-administration of NSAIDs was associated with significantly higher MTX concentrations at 72 h (p = 0.019). The dose optimizer tool exhibited a high consistency in predicting MTX AUC compared to the actual AUC (r = 0.821, p < 0.001) in the validation set.

CONCLUSION

The dose optimizer tool could be used to estimate individual PK parameters, and optimize personalized MTX therapy in particular patients.

The role of TandemHeartTM combined with ProtekDuoTM as right ventricular support device: A simulation approach

BACKGROUND AND OBJECTIVE

Right ventricular failure increases short-term mortality in the setting of acute myocardial infarction, cardiogenic shock, advanced left-sided heart failure and pulmonary arterial hypertension. Percutaneous and surgically implanted right ventricular assist devices (RVAD) have been investigated in different clinical settings. The use of the ProtekDuo™ is currently a promising approach due to its features such as groin-free approach leading to early mobilisation, easy percutaneous deployment, compatibility with different pumps and oxygenators, and adaptability to different configurations. The aim of this work was to simulate the behaviour of the TandemHeart™ pump applied "in series" and "in parallel" mode and the combination of TandemHeart™ and ProtekDuo™ cannula as RVAD using CARDIOSIM© software simulator platform.

METHODS

To achieve our aim, two new modules have been implemented in the software. The first module simulated the TandemHeart™ pump in RVAD configuration, both as a right atrial-pulmonary arterial and a right ventricular-pulmonary arterial connection, driven by four different rotational speeds. The second module reproduced the behaviour of the ProtekDuo™ cannula plus TandemHeart™.

RESULTS

The effects induced on the main haemodynamic and energetic variables were analysed for both the right atrial-pulmonary arterial and right ventricular-pulmonary arterial configuration with different pump rotational speed and following Milrinone administration. The TandemHeart™ increased right ventricular end systolic volume by 10 %, larger increases were evident for higher speeds (6000 and 7500 rpm) and connections with 21-Fr inflow and 17-Fr outflow cannula, respectively. Both TandemHeart™ and ProtekDuo™ support increased left ventricular preload. When different RVAD settings were used, Milrinone therapy increased the left ventricular pressure-volume area and decreased the right pressure-volume area slightly. A reduction in oxygen consumption (demand) was observed with reduced right stroke work and pressure volume area and increased oxygen supply (coronary blood flow).

CONCLUSIONS

The outcome of our simulations confirms the effective haemodynamic assistance provided by the ProtekDuo™ as observed in the acute clinical setting. A simulation approach based on pressure-volume analysis combined with modified time-varying elastance and lumped-parameter modelling remains a suitable tool for clinical applications.

The predictive role of the TAPSE/sPAP ratio for cardiovascular events and mortality in systemic sclerosis with pulmonary hypertension

Introduction

Reduced TAPSE/sPAP ratio has recently emerged as a predictive parameter risk factor for PH, however its role in SSc has been poorly investigated. The aim of the study was to investigate the prognostic value of the TAPSE/sPAP ratio for the prediction of mortality and cardiovascular events in patients with SSc complicated by PH. A comparison between SSc patients with PAH (SSc-PAH) and those with PH and significant ILD (SSc-PH) was also carried out.

Materials and methods

A retrospective single-center study in which all patients having SSc-complicated by PH-referring to the Scleroderma-Unit of the AOU Policlinico of Modena, from October 2013 to October 2023 were evaluated. All SSc patients underwent recurrent clinical examination, routine blood chemistry analysis, functional, instrumental evaluation.

Results

61 SSc patients (F/M 52/9) were enrolled. During the follow-up, 60.1% of patients experienced at least one cardiovascular event and 62% died. The main causes of death were PH (39.4%) and other heart-related events (39.4%). The TAPSE/sPAP ratio was significantly lower in deceased patients compared to survivors (mm/mmHg 0.3 ± 0.12SD vs. 0.48 ± 0.17SD, p < 0.001). Compared to the SSc-PAH subgroup, the SSc-PH patients had lower survival rates (55.3 ± 31.2 SD months vs. 25 ± 19 SD, p = 0,05). At the multivariate analysis, TAPSE/sPAP ratio <0.32 mm/mmHg, male gender, and the presence of significant ILD were identified as independent predictors of mortality and cardiovascular events.

Conclusion

Our work confirmed the predictive role of the TAPSE/sPAP ratio for mortality and cardiovascular events in patients with SSc complicated by PH.

Non-invasive surrogates for right Ventricular-Pulmonary arterial coupling: a systematic review and Meta-Analysis

Right ventricle-pulmonary artery (RV-PA) coupling describes the energetic relationship between RV contractility and its afterload. The gold standard for assessment of this relationship requires invasive pressure-volume (PV) loop measurements. Non-invasive surrogates of RV-PA coupling have been developed, such as the echocardiographic tricuspid annular plane systolic excursion to pulmonary artery systolic pressure ratio (TAPSE/PASP), but their performance has not been systematically assessed. We sought to assess performance of TAPSE/PASP ratio compared to PV loop-defined RV-PA coupling. A systematic search was conducted. Studies were included if PV loop derived RV-PA coupling metrics were compared to echocardiographic or magnetic resonance imaging surrogates. We conducted a meta-analysis of TAPSE/PASP correlation to PV loop-defined RV-PA coupling. 1452 studies were identified in the initial search, of which ten met inclusion criteria. Five studies allowed for pooled analysis of TAPSE/PASP to Ees/Ea correlation (r = 0.52, 95% confidence interval 0.36-0.65). There was moderate heterogeneity across the pooled studies. Despite the common use of Non-invasive surrogates of RV-PA coupling, there is only moderate correlation with gold standard measurements. These metrics do not inform on the individual components of RV-PA coupling, limiting their use in the management of patients with RV dysfunction.

Prognostic Relevance of Tricuspid Annular Plane Systolic Excursion to Systolic Pulmonary Arterial Pressure Ratio and Its Association With Exercise Hemodynamics in Patients With Normal or Mildly Elevated Resting Pulmonary Arterial Pressure

BACKGROUND

Echocardiographic tricuspid annular plane systolic excursion (TAPSE) to systolic pulmonary arterial pressure (sPAP) ratio is a noninvasive surrogate for right ventricle (RV)-pulmonary arterial (PA) coupling. It has been related to outcome in patients with moderate to severe pulmonary hypertension (PH).

RESEARCH QUESTION

Is RV-PA coupling of prognostic relevance in patients with suspected PH, but only normal or mildly elevated mean pulmonary arterial pressure (mPAP), and is it associated with impaired exercise capacity and exercise hemodynamics?.

STUDY DESIGN AND METHODS

Patients with mPAP of < 25 mm Hg who underwent echocardiography and exercise right heart catheterization in our PH clinic were analyzed retrospectively. Mild PH was defined as mPAP of 21 to 24 mm Hg and exercise PH (EPH) was defined as an mPAP to cardiac output (CO) slope of > 3 mm Hg/L/min. Multivariate analysis was performed to identify independent predictors for clinical worsening (CW), defined by disease-related hospitalization, transplantation, or death.

RESULTS

Two hundred thirty-seven patients (155 female with median age, 64 years [interquartile range (IQR), 54-73 years]; no PH: n = 147; mild PH: n = 90; EPH: n = 202) were included. During the observation time of 63 months (IQR, 29-104 months), 36 patients died and 126 CW events occurred. TAPSE to sPAP ratio was an age- and sex-independent predictor of mortality (hazard ratio [HR], 0.09; 95% CI, 0.01-0.62; P = .014) and CW (HR, 0.05; 95% CI, 0.35-0.78; P = .002). TAPSE to sPAP ratio also was correlated significantly to 6-minute walk distance (6MWD; r = 0.33; P < .001) and exercise hemodynamics (mPAP to CO slope: rρ = -0.56; P < .001). The best multivariate predictive model for CW in this population consisted of TAPSE to sPAP ratio (HR, 0.71; 95% CI, 0.53-0.95; P = .021), NT-proBNP (HR, 1.15; 95% CI, 0.99-1.34; P = .065), and 6MWD (HR, 0.998; 95% CI, 0.995-1.00; P = .042).

INTERPRETATION

In patients with suspected PH, but normal or only mildly elevated resting mPAP, TAPSE to sPAP ratio is an independent predictor of outcome. In addition, it is associated significantly with exercise capacity and exercise hemodynamics and may be a helpful tool in the prediction of future CW of this patient population.

Pulmonary Hypertension and Right Ventricle: A Pathophysiological Insight

Background

Pulmonary hypertension (PH) is a pulmonary vascular disease characterized by elevated pulmonary vascular pressure. Long-term PH, irrespective of its etiology, leads to increased right ventricular (RV) pressure, RV hypertrophy, and ultimately, RV failure.

Main body

Research indicates that RV failure secondary to hypertrophy remains the primary cause of mortality in pulmonary arterial hypertension (PAH). However, the impact of PH on RV structure and function under increased overload remains incompletely understood. Several mechanisms have been proposed, including extracellular remodeling, RV hypertrophy, metabolic disturbances, inflammation, apoptosis, autophagy, endothelial-to-mesenchymal transition, neurohormonal dysregulation, capillary rarefaction, and ischemia.

Conclusions

Studies have demonstrated the significant role of oxidative stress in the development of RV failure. Understanding the interplay among these mechanisms is crucial for the prevention and management of RV failure in patients with PH.

[Research progress of right ventricular strain imaging evaluation technology in pulmonary arterial hypertension]

Pulmonary arterial hypertension (PAH) has a subtle onset, rapid progression, and high mortality rate. Imaging evaluation is an important diagnostic and follow-up method for PAH patients. Right ventricular (RV) strain evaluation can identify early changes in RV function and predict the prognosis. Currently, various methods such as tissue Doppler imaging, velocity vector imaging, speckle tracking imaging, and cardiac magnetic resonance imaging can be used to evaluate RV strain in PAH patients. This article aims to summarize the research progress of RV strain imaging evaluation technology in PAH patients, in order to provide a basis for clinical diagnosis and follow-up of PAH patients.

Current trends and latest developments in echocardiographic assessment of right ventricular function: load dependency perspective

Right ventricle (RV) failure is a common complication of many cardiopulmonary diseases. Since it has a significant adverse impact on prognosis, precise determination of RV function is crucial to guide clinical management. However, accurate assessment of RV function remains challenging owing to the difficulties in acquiring its intricate pathophysiology and imaging its complex anatomical structure. In addition, there is historical attention focused exclusively on the left ventricle assessment, which has led to overshadowing and delayed development of RV evaluation. Echocardiography is the first-line and non-invasive bedside clinical tool for assessing RV function. Tricuspid annular plane systolic excursion (TAPSE), RV systolic tissue Doppler velocity of the tricuspid annulus (RV S'), and RV fractional area change (RV FAC) are conventional standard indices routinely used for RV function assessment, but accuracy has been subject to several limitations, such as load-dependency, angle-dependency, and localized regional assessment. Particularly, load dependency is a vexing issue, as the failing RV is always in a complex loading condition, which alters the values of echocardiographic parameters and confuses clinicians. Recently, novel echocardiographic methods for improved RV assessment have been developed. Specifically, "strain", "RV-pulmonary arterial (PA) coupling", and "RV myocardial work" are newly applied methods for RV function assessment, a few of which are designed to surmount the load dependency by taking into account the afterload on RV. In this narrative review, we summarize the latest data on these novel RV echocardiographic parameters and highlight their strengths and limitations. Since load independency is one of the primary advantages of these, we particularly emphasize this aspect.

Impairment in Right Ventricular-Pulmonary Arterial Coupling in Overweight and Obesity

Background: The association of obesity with right ventricular function and the interplay between right heart and pulmonary circulation is incompletely understood. We evaluate the role of obesity as a determinant of right ventricular-pulmonary artery coupling (RVAC). Methods: We retrospectively studied consecutive subjects without overt cardiovascular or pulmonary disease. Subjects were stratified according to body mass index (BMI) as normal weight, overweight, or obese. A transthoracic echocardiographic study was used to assess left and right heart functional and structural parameters. RVAC was assessed using the ratio of peak systolic velocity of the tricuspid annulus to pulmonary artery systolic pressure (PASP). Results: A total of 145 subjects were enrolled with diabetes mellitus incidence higher in obese. There was no difference in left ventricular global longitudinal strain and in PASP or markers of right ventricular systolic function based on BMI. RVAC was significantly lower in the presence of obesity (normal weight: 0.52 (0.19) cm·(sec·mmHg)-1 vs. overweight: 0.47 (0.16) cm·(sec·mmHg)-1 vs. obese: 0.43 (0.14) cm·(sec·mmHg)-1, p = 0.03), even after adjustment for confounders (β: -0.085, 95% confidence interval: -0.163, -0.009, p = 0.029). Conclusions: Our findings highlight the relationship between metabolic impairment and RVAC, suggesting additional mechanisms for heart failure development observed in obese subjects.

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.

Comparison of admittance and cardiac magnetic resonance generated pressure-volume loops in a porcine model

Objective. Pressure-volume loop analysis, traditionally performed by invasive pressure and volume measurements, is the optimal method for assessing ventricular function, while cardiac magnetic resonance (CMR) imaging is the gold standard for ventricular volume estimation. The aim of this study was to investigate the agreement between the assessment of end-systolic elastance (Ees) assessed with combined CMR and simultaneous pressure catheter measurements compared with admittance catheters in a porcine model.Approach. Seven healthy pigs underwent admittance-based pressure-volume loop evaluation followed by a second assessment with CMR during simultaneous pressure measurements.Main results. Admittance overestimated end-diastolic volume for both the left ventricle (LV) and the right ventricle (RV) compared with CMR. Further, there was an underestimation of RV end-systolic volume with admittance. For the RV, however, Ees was systematically higher when assessed with CMR plus simultaneous pressure measurements compared with admittance whereas there was no systematic difference in Ees but large differences between admittance and CMR-based methods for the LV.Significance. LV and RV Ees can be obtained from both admittance and CMR based techniques. There were discrepancies in volume estimates between admittance and CMR based methods, especially for the RV. RV Ees was higher when estimated by CMR with simultaneous pressure measurements compared with admittance.

Advanced hemodynamic and cluster analysis for identifying novel RV function subphenotypes in patients with pulmonary hypertension

BACKGROUND

Quantifying right ventricular (RV) function is important to describe the pathophysiology of in pulmonary hypertension (PH). Current phenotyping strategies in PH rely on few invasive hemodynamic parameters to quantify RV dysfunction severity. The aim of this study was to identify novel RV phenotypes using unsupervised clustering methods on advanced hemodynamic features of RV function.

METHODS

Participants were identified from the University of Arizona Pulmonary Hypertension Registry (n = 190). RV-pulmonary artery coupling (Ees/Ea), RV systolic (Ees), and diastolic function (Eed) were quantified from stored RV pressure waveforms. Consensus clustering analysis with bootstrapping was used to identify the optimal clustering method. Pearson correlation analysis was used to reduce collinearity between variables. RV cluster subphenotypes were characterized using clinical data and compared to pulmonary vascular resistance (PVR) quintiles.

RESULTS

Five distinct RV clusters (C1-C5) with distinct RV subphenotypes were identified using k-medoids with a Pearson distance matrix. Clusters 1 and 2 both have low diastolic stiffness (Eed) and afterload (Ea) but RV-PA coupling (Ees/Ea) is decreased in C2. Intermediate cluster (C3) has a similar Ees/Ea as C2 but with higher PA pressure and afterload. Clusters C4 and C5 have increased Eed and Ea but C5 has a significant decrease in Ees/Ea. Cardiac output was high in C3 distinct from the other clusters. In the PVR quintiles, contractility increased and stroke volume decreased as a function of increased afterload. World Symposium PH classifications were distributed across clusters and PVR quintiles.

CONCLUSIONS

RV-centric phenotyping offers an opportunity for a more precise-medicine-based management approach.

Exploratory analysis of the accuracy of echocardiographic parameters for the assessment of right ventricular function and right ventricular-pulmonary artery coupling

Echocardiography is a widely used modality for the assessment of right ventricular (RV) function; however, few studies have comprehensively compared the accuracy of echocardiographic parameters using invasively obtained reference values. Therefore, this exploratory study aimed to compare the accuracy of echocardiographic parameters of RV function and RV-pulmonary artery (PA) coupling. We calculated four indices of RV function (end-systolic elastance [Ees] for systolic function [contractility], τ for relaxation, and β and end-diastolic elastance [Eed] for stiffness), and an index of RV-PA coupling (Ees/arterial elastance [Ea]), using pressure catheterization, cardiac magnetic resonance imaging, and a single-beat method. We then compared the correlations of RV indices with echocardiographic parameters. In 63 participants (54 with pulmonary hypertension (PH) and nine without PH), Ees and τ correlated with several echocardiographic parameters, such as RV diameter and area, but the correlations were moderate (|correlation coefficients (ρ)| < 0.5 for all parameters). The correlations of β and Eed with echocardiographic parameters were weak, with |ρ| < 0.4. In contrast, Ees/Ea closely correlated with RV free wall longitudinal strain (RVFW-LS)/estimated systolic PA pressure (eSPAP) (ρ = -0.72). Ees/Ea also correlated with tricuspid annular plane systolic excursion/eSPAP, RV diameter, and RV end-systolic area, with |ρ | >0.65. In addition, RVFW-LS/eSPAP yielded high sensitivity (0.84) and specificity (0.75) for detecting reduced Ees/Ea. The present study indicated a limited accuracy of echocardiographic parameters in assessing RV systolic and diastolic function. In contrast to RV function, they showed high accuracy for assessing RV-PA coupling, with RVFW-LS/eSPAP exhibiting the highest accuracy.

Right Ventricular Contractility and Pulmonary Arterial Coupling After Less Invasive Left Ventricular Assist Device Implantation

Right ventricular failure contributes significantly to morbidity and mortality after left ventricular assist device implantation. Recent data suggest a less invasive strategy (LIS) via thoracotomy may be associated with less right ventricular failure than conventional median sternotomy (CMS). However, the impact of these approaches on load-independent right ventricular (RV) contractility and RV-pulmonary arterial (RV-PA) coupling remains uncertain. We hypothesized that the LIS approach would be associated with preserved RV contractility and improved RV-PA coupling compared with CMS. We performed a retrospective study of patients who underwent durable, centrifugal left ventricular assist device implantation and had paired hemodynamic assessments before and after implantation. RV contractility (end-systolic elastance [Ees]), RV afterload (pulmonary effective arterial elastance [Ea]), and RV-PA coupling (Ees/Ea) were determined using digitized RV pressure waveforms. Forty-two CMS and 21 LIS patients were identified. Preimplant measures of Ees, Ea, and Ees/Ea were similar between groups. After implantation, Ees declined significantly in the CMS group (0.60-0.40, p  = 0.008) but not in the LIS group (0.67-0.58, p  = 0.28). Coupling (Ees/Ea) was unchanged in CMS group (0.54-0.59, p  = 0.80) but improved significantly in the LIS group (0.58-0.71, p  = 0.008). LIS implantation techniques may better preserve RV contractility and improve RV-PA coupling compared with CMS.

The value of right ventricular to pulmonary arterial coupling in the critically ill: a National Echocardiography Database of Australia (NEDA) substudy

BACKGROUND

Right ventricular (RV) function is tightly coupled to afterload, yet echocardiographic indices of RV function are frequently assessed in isolation. Normalizing RV function for afterload (RV-PA coupling) using a simplified ratio of tricuspid annular plane systolic excursion (TAPSE)/ tricuspid regurgitant velocity (TRV) could help to identify RV decompensation and improve risk stratification in critically ill patients. This is the first study to explore the distribution of TAPSE/TRV ratio and its prognostic relevance in a large general critical care cohort.

METHODS

We undertook retrospective analysis of echocardiographic, clinical, and mortality data of intensive care unit (ICU) patients between January 2012 and May 2017. A total of 1077 patients were included and stratified into tertile groups based on TAPSE/TRV ratio: low (< 5.9 mm.(m/s)-1), middle (≥ 5.9-8.02 mm.(m/s)-1), and high (≥ 8.03 mm.(m/s)-1). The distribution of the TAPSE/TRV ratio across ventricular function subtypes of normal, isolated left ventricular (LV), isolated RV, and biventricular dysfunction was explored. The overall prognostic relevance of the TAPSE/TRV ratio was tested, including distribution across septic, cardiovascular, respiratory, and neurological subgroups.

RESULTS

Higher proportions of ventricular dysfunctions were seen in low TAPSE/TRV tertiles. TAPSE/TRV ratio is impacted by LV systolic function but to a lesser extent than RV dysfunction or biventricular dysfunction. There was a strong inverse relationship between TAPSE/TRV ratio and survival. After multivariate analysis, higher TAPSE/TRV ratios (indicating better RV-PA coupling) were independently associated with lower risk of death in ICU (HR 0.927 [0.872-0.985], p < 0.05). Kaplan-Meier analysis demonstrated higher overall survival in middle and high tertiles compared to low tertiles (log rank p < 0.0001). The prognostic relevance of TAPSE/TRV ratio was strongest in respiratory and sepsis subgroups. Patients with TAPSE/TRV < 5.9 mm (m/s)-1 had a significantly worse prognosis than those with higher TAPSE/TRV ratios.

CONCLUSION

The TAPSE/TRV ratio has prognostic relevance in critically ill patients. The prognostic power may be stronger in respiratory and septic subgroups. Larger prospective studies are needed to investigate the role of TAPSE/TRV in pre-specified subgroups including its role in clinical decision-making.

Comparison of prognostic value among echocardiographic surrogates of right ventricular-pulmonary arterial coupling: A three-dimensional echocardiographic study

OBJECTIVES

Right ventricular (RV)-pulmonary arterial (PA) coupling is important in various cardiac diseases. Recently, several echocardiographic surrogates for RV-PA coupling have been proposed and reported to be useful in predicting outcomes. However, it remains unclear which surrogate is the most clinically relevant. This study aimed to comprehensively compare the prognostic value of different echocardiographic RV-PA coupling surrogates.

METHODS

We retrospectively reviewed 242 patients with various cardiac conditions who underwent comprehensive transthoracic echocardiography with three-dimensional RV data. In addition to conventional parameters including tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), and PA systolic pressure (PASP), we analyzed RV free wall and global longitudinal strain (FWLS and GLS). We also obtained RV ejection fraction (RVEF), stroke volume (SV), and end-systolic volume (ESV) using three-dimensional RV analysis. RV-PA coupling surrogates were calculated as TAPSE/PASP, FAC/PASP, FWLS/PASP, GLS/PASP, RVEF/PASP, and SV/ESV. The study endpoint was a composite outcome of all-cause death or cardiovascular hospitalization within 1 year.

RESULTS

In multivariable analysis, all the RV-PA coupling surrogates were independent predictors of the outcome. Among the surrogates, the model with TAPSE/PASP showed the lowest prognostic value in model fit and discrimination ability, whereas the model with RVEF/PASP exhibited the highest prognostic value. The partial likelihood ratio test indicated that the model with RVEF/PASP was significantly better than the model with TAPSE/PASP (p < .024).

CONCLUSION

All the RV-PA coupling surrogates were independent predictors of the outcome. Notably, RVEF/PASP had the highest prognostic value among the surrogates.

MRI pulmonary artery flow detects lung vascular pathology in preterms with lung disease

BACKGROUND

Pulmonary vascular disease (PVD) affects the majority of preterm neonates with bronchopulmonary dysplasia (BPD) and significantly determines long-term mortality through undetected progression into pulmonary hypertension. Our objectives were to associate characteristics of pulmonary artery (PA) flow and cardiac function with BPD-associated PVD near term using advanced magnetic resonance imaging (MRI) for improved risk stratification.

METHODS

Preterms <32 weeks postmenstrual age (PMA) with/without BPD were clinically monitored including standard echocardiography and prospectively enrolled for 3 T MRI in spontaneous sleep near term (AIRR (Attention to Infants at Respiratory Risks) study). Semi-manual PA flow quantification (phase-contrast MRI; no BPD n=28, mild BPD n=35 and moderate/severe BPD n=25) was complemented by cardiac function assessment (cine MRI).

RESULTS

We identified abnormalities in PA flow and cardiac function, i.e. increased net forward volume right/left ratio, decreased mean relative area change and pathological right end-diastolic volume, to sensitively detect BPD-associated PVD while correcting for PMA (leave-one-out area under the curve 0.88, sensitivity 0.80 and specificity 0.81). We linked these changes to increased right ventricular (RV) afterload (RV-arterial coupling (p=0.02), PA mid-systolic notching (t2; p=0.015) and cardiac index (p=1.67×10-8)) and correlated echocardiographic findings. Identified in moderate/severe BPD, we successfully applied the PA flow model in heterogeneous mild BPD cases, demonstrating strong correlation of PVD probability with indicators of BPD severity, i.e. duration of mechanical ventilation (rs=0.63, p=2.20×10-4) and oxygen supplementation (rs=0.60, p=6.00×10-4).

CONCLUSIONS

Abnormalities in MRI PA flow and cardiac function exhibit significant, synergistic potential to detect BPD-associated PVD, advancing the possibilities of risk-adapted monitoring.

[18 F] -FAPI-42 PET/CT assessment of Progressive right ventricle fibrosis under pressure overload

BACKGROUND

Right heart failure (RHF) is a complication of pulmonary hypertension (PH) and increases the mortality independently of the underlying disease. However, the process of RHF development and progression is not fully understood. We aimed to develop effective approaches for early diagnosis and precise evaluation of RHF.

METHODS

Right ventricle (RV) pressure overload was performed via pulmonary artery banding (PAB) surgery in Sprague-Dawley (SD) rats to induce RHF. Echocardiography, right heart catheterization, histological staining, fibroblast activation protein (FAP) immunofluorescence and 18 F-labelled FAP inhibitor-42 ([18 F] -FAPI-42) positron emission tomography/computed tomography (PET/CT) were performed at day 3, week 1, 2, 4 and 8 after PAB. RNA sequencing was performed to explore molecular alterations between PAB and sham group at week 2 and week 4 after PAB respectively.

RESULTS

RV hemodynamic disorders were aggravated, and RV function was declined based on right heart catheterization and echocardiography at week 2, 4 and 8 after PAB. Progressive cardiac hypertrophy, fibrosis and capillary rarefaction could be observed in RV from 2 to 8 weeks after PAB. RNA sequencing indicated 80 upregulated genes and 43 downregulated genes in the RV at both week 2 and week 4 after PAB; Gene Ontology (GO) analysis revealed that fibrosis as the most significant biological process in the RV under pressure overload. Immunofluorescence indicated that FAP was upregulated in the RV from week 2 to week 8 after PAB; and [18 F] -FAPI-42 PET/CT revealed FAPI uptake was significantly higher in RV at week 2 and further increased at week 4 and 8 after PAB.

CONCLUSION

RV function is progressively declined with fibrosis as the most prominent molecular change after pressure overload, and [18 F] -FAPI-42 PET/CT is as sensitive and accurate as histopathology in RV fibrosis evaluation.

Standardization of the Right Heart Catheterization and the Emerging Role of Advanced Hemodynamics in Heart Failure

The accurate assessment of hemodynamics is paramount to providing timely and efficacious care for patients presenting in cardiogenic shock. Recently, the regular use of the pulmonary artery catheter in cardiogenic shock has had a resurgence with emerging data indicating improved survival in the modern era. Optimal multidisciplinary management of advanced heart failure and cardiogenic shock relies on our ability to effectively communicate and understand the complete hemodynamic assessment. Standardization of data acquisition and a renewed focus on the physiological processes, and thresholds driving disease progression, including the coupling ratio and myocardial reserve, are needed to fully understand and interpret the hemodynamic assessment. This State-of-the-Art review discusses best practices in the cardiac catheterization laboratory as well as emerging data on the prognostic role of emerging advanced hemodynamic parameters.

Echocardiographic evaluation of right ventricular diastolic function in pulmonary hypertension

Background

Right ventricular (RV) diastolic dysfunction may be prognostic in pulmonary hypertension (PH). However, its assessment is complex and relies on conductance catheterisation. We aimed to evaluate echocardiography-based parameters as surrogates of RV diastolic function, provide validation against the gold standard, end-diastolic elastance (Eed), and define the prognostic impact of echocardiography-derived RV diastolic dysfunction.

Methods

Patients with suspected PH who underwent right heart catheterisation including conductance catheterisation were prospectively recruited. In this study population, an echocardiography-based RV diastolic function surrogate was derived. Survival analyses were performed in patients with precapillary PH in the Giessen PH Registry, with external validation in patients with pulmonary arterial hypertension at Sapienza University (Rome).

Results

In the derivation cohort (n=61), the early/late diastolic tricuspid inflow velocity ratio (E/A) and early tricuspid inflow velocity/early diastolic tricuspid annular velocity ratio (E/e') did not correlate with Eed (p>0.05). Receiver operating characteristic analysis revealed a large area under the curve (AUC) for the peak lateral tricuspid annulus systolic velocity/right atrial area index ratio (S'/RAAi) to detect elevated Eed (AUC 0.913, 95% confidence interval (CI) 0.839-0.986) and elevated end-diastolic pressure (AUC 0.848, 95% CI 0.699-0.998) with an optimal threshold of 0.81 m2·s-1·cm-1. Subgroup analyses demonstrated a large AUC in patients with preserved RV systolic function (AUC 0.963, 95% CI 0.882-1.000). Survival analyses confirmed the prognostic relevance of S'/RAAi in the Giessen PH Registry (n=225) and the external validation cohort (n=106).

Conclusions

Our study demonstrates the usefulness of echocardiography-derived S'/RAAi for noninvasive assessment of RV diastolic function and prognosis in 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.

Pressure Overload and Right Ventricular Failure: From Pathophysiology to Treatment

Right ventricular failure (RVF) is often caused by increased afterload and disrupted coupling between the right ventricle (RV) and the pulmonary arteries (PAs). After a phase of adaptive hypertrophy, pressure-overloaded RVs evolve towards maladaptive hypertrophy and finally ventricular dilatation, with reduced stroke volume and systemic congestion. In this article, we review the concept of RV-PA coupling, which depicts the interaction between RV contractility and afterload, as well as the invasive and non-invasive techniques for its assessment. The current principles of RVF management based on pathophysiology and underlying etiology are subsequently discussed. Treatment strategies remain a challenge and range from fluid management and afterload reduction in moderate RVF to vasopressor therapy, inotropic support and, occasionally, mechanical circulatory support in severe RVF.

A new assessment method for right ventricular diastolic function using right heart catheterization by pressure-volume loop

Diastolic stiffness coefficient (β) and end-diastolic elastance (Eed) are ventricular-specific diastolic parameters. However, the diastolic function of right ventricle had not been investigated sufficiently due to the lack of established evaluation method. We evaluated the validity of these parameters calculated using only data of right heart catheterization (RHC) and assessed it in patients with restrictive cardiomyopathy (RCM) and cardiac amyloidosis. We retrospectively analyzed 46 patients with heart failure who underwent RHC within 10 days of cardiac magnetic resonance (CMR). Right ventricular end-diastolic volume and end-systolic volume were calculated using only RHC data, which were found to be finely correlated with those obtained from CMR. β and Eed calculated by this method were also significantly correlated with those derived from conventional method using CMR. By this method, β and Eed were significantly higher in RCM with amyloidosis group than dilated cardiomyopathy group. In addition, the β and Eed calculated by our method were finely correlated with E/A ratio on echocardiography. We established an easy method to estimate β and Eed of right ventricle from only RHC. The method finely demonstrated right ventricular diastolic dysfunction in patients with RCM and amyloidosis.

Role of Exercise Stress Echocardiography in Pulmonary Hypertension

Resting and exercise right heart catheterisation is the gold standard method to diagnose and differentiate types of pulmonary hypertension (PH). As it carries technical challenges, the question arises if non-invasive exercise stress echocardiography may be used as an alternative. Exercise echocardiography can unmask exercise PH, detect the early stages of left ventricular diastolic dysfunction, and, therefore, differentiate between pre- and post-capillary PH. Regardless of the underlying aetiology, a developed PH is associated with increased mortality. Parameters of overt right ventricle (RV) dysfunction, including RV dilation, reduced RV ejection fraction, and elevated right-sided filling pressures, are detectable with resting echocardiography and are associated with worse outcome. However, these measures all fail to identify occult RV dysfunction. Echocardiographic measures of RV contractile reserve during exercise echocardiography are very promising and provide incremental prognostic information on clinical outcome. In this paper, we review pulmonary haemodynamic response to exercise, briefly describe the modalities for assessing pulmonary haemodynamics, and discuss in depth the contemporary key clinical application of exercise stress echocardiography in patients with PH.

Assessment of Right Ventricular Function-a State of the Art

PURPOSE OF REVIEW

The right ventricle (RV) has a complex geometry and physiology which is distinct from the left. RV dysfunction and failure can be the aftermath of volume- and/or pressure-loading conditions, as well as myocardial and pericardial diseases.

RECENT FINDINGS

Echocardiography, magnetic resonance imaging and right heart catheterisation can assess RV function by using several qualitative and quantitative parameters. In pulmonary hypertension (PH) in particular, RV function can be impaired and is related to survival. An accurate assessment of RV function is crucial for the early diagnosis and management of these patients. This review focuses on the different modalities and indices used for the evaluation of RV function with an emphasis on PH.

Assessment and diagnosis of right ventricular failure-retrospection and future directions

The right ventricle (RV) has a critical role in hemodynamics and right ventricular failure (RVF) often leads to poor clinical outcome. Despite the clinical importance of RVF, its definition and recognition currently rely on patients' symptoms and signs, rather than on objective parameters from quantifying RV dimensions and function. A key challenge is the geometrical complexity of the RV, which often makes it difficult to assess RV function accurately. There are several assessment modalities currently utilized in the clinical settings. Each diagnostic investigation has both advantages and limitations according to its characteristics. The purpose of this review is to reflect on the current diagnostic tools, consider the potential technological advancements and propose how to improve the assessment of right ventricular failure. Advanced technique such as automatic evaluation with artificial intelligence and 3-dimensional assessment for the complex RV structure has a potential to improve RV assessment by increasing accuracy and reproducibility of the measurements. Further, noninvasive assessments for RV-pulmonary artery coupling and right and left ventricular interaction are also warranted to overcome the load-related limitations for the accurate evaluation of RV contractile function. Future studies to cross-validate the advanced technologies in various populations are required.

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.

Clinical Usefulness of Right Ventricle-Pulmonary Artery Coupling in Cardiovascular Disease

Right ventricular-pulmonary artery coupling (RV-PA coupling) refers to the relationship between RV contractility and RV afterload. Normal RV-PA coupling is maintained only when RV function and pulmonary vascular resistance are appropriately matched. RV-PA uncoupling occurs when RV contractility cannot increase to match RV afterload, resulting in RV dysfunction and right heart failure. RV-PA coupling plays an important role in the pathophysiology and progression of cardiovascular diseases. Therefore, early and accurate evaluation of RV-PA coupling is of great significance for a patient's condition assessment, clinical decision making, risk stratification, and prognosis judgment. RV-PA coupling can be assessed by using invasive or noninvasive approaches. The aim of this review was to summarize the pathological mechanism and evaluation methods of RV-PA coupling, the advantages and disadvantages of each method, and the application value of RV-PA coupling in various cardiovascular diseases.

Right ventricular function across the spectrum of health and disease

Knowledge of right ventricular (RV) structure and function has historically lagged behind that of the left ventricle (LV). However, advancements in invasive and non-invasive evaluations, combined with epidemiological analyses, have advanced the current understanding of RV (patho)physiology across the spectrum of health and disease, and reinforce the centrality of the RV in contributing to clinical outcomes. In the healthy heart, ventricular-arterial coupling is preserved during rest and in response to increased myocardial demand (eg, exercise) due to substantial RV contractile reserve. However, prolonged exposure to increased myocardial demand, such as endurance exercise, may precipitate RV dysfunction, suggesting that unlike the LV, the RV is unable to sustain high levels of contractility for extended periods of time. Emerging data increasingly indicate that both LV and RV function contribute to clinical heart failure. Reductions in quality-of-life, functional capacity and overall clinical outcomes are worsened among patients with heart failure when there is evidence of RV dysfunction. In addition, the RV is adversely impacted by pulmonary vascular disease, and among affected patients, overall RV function differs based on mechanisms of the underlying pulmonary hypertension, which may result from variations in sarcomere function within RV cardiomyocytes.

A review of cardio-pulmonary microvascular dysfunction in pulmonary hypertension

Microvascular dysfunction progressing to pulmonary hypertension can be a primary cause of right ventricular failure or a secondary cause because of an underlying systemic illness. Little is known regarding the etiology and epidemiology of coronary microvascular dysfunction in pulmonary hypertension. Despite this limitation, its presence has been described in patients with pulmonary hypertension. This review focuses on the pathogenesis of cardiac and pulmonary microvascular dysfunction in pulmonary hypertension. Additionally, this review provides a contemporary assessment on the diagnosis and treatment of microvascular dysfunction in patients in pulmonary hypertension. This topic is important to raise awareness of microvascular dysfunction in the coronary and pulmonary circulation, so that future studies will investigate its impact on the pulmonary hypertension patient cohort.

The prognostic role of the echocardiographic tricuspid annular plane systolic excursion/systolic pulmonary arterial pressure (TAPSE/sPAP) ratio and its relationship with NT-proANP plasma level in systemic sclerosis

Background

The tricuspid annular plane systolic excursion/systolic pulmonary arterial pressure (TAPSE/sPAP) ratio is an echocardiographic estimation of the right ventricle to pulmonary artery (RV/PA) coupling, with a validated prognostic role in different clinical settings. Systemic sclerosis (SSc) patients without evident cardiovascular involvement frequently display subtle RV impairment. The amino-terminal atrial natriuretic peptide (NT-proANP) plasma level relates to SSc disease progression and mortality. We aimed to assess the prognostic value of the TAPSE/sPAP ratio and its relationship with NT-proANP plasma level in SSc patients without overt cardiovascular involvement.

Methods

We retrospectively analysed 70 SSc consecutive patients, with no clinical evidence of cardiovascular involvement or pulmonary hypertension (PH), and 30 healthy controls (HC) in a retrospective, single-centre study. All SSc patients underwent recurrent clinical and echocardiographic assessments and NT-proANP plasma level was assessed at baseline. SSc-related cardiovascular events and deaths were extracted during a 6-year follow-up. The complete work-up for the diagnosis, treatment and management of PH performed along the 6 years of follow-up referred to the 2015 European Society of Cardiology guidelines.

Results

Systemic sclerosis patients showed lower TAPSE/sPAP ratio at baseline compared to HC [SSc median value = 0.71 mm/mmHg, (IQR 0.62-0.88) vs. HC median value = 1.00 mm/mmHg, (IQR 0.96-1.05); p < 0.001]. Multivariable Cox analysis revealed TAPSE/sPAP ratio as an independent predictor for SSc-related cardiovascular events [HR = 3.436 (95% CI 1.577-7.448); p = 0.002] and mortality [HR = 3.653 (95% CI 1.712-8.892); p = 0.014]. The value of TAPSE/sPAP ratio < 0.7 mm/mmHg was identified as an optimal cut-off for predicting adverse outcomes (p < 0.001) by receiver operating characteristic (ROC) analyses. NT-proANP level significantly related to TAPSE/sPAP ratio (r = 0.52, p < 0.001). TAPSE/sPAP ratio combined with NT-proANP showed an overall significant prognostic role in this SSc population, confirmed by Kaplan-Meier analysis (Log rank p < 0.001).

Conclusion

The TAPSE/sPAP ratio, as an index of RV/PA coupling, is an affordable predictor of cardiovascular events and mortality in SSc and, combined with NT-proANP level, may improve the clinical phenotyping and prognostic stratification of SSc patients.

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.

A computational study of aortic insufficiency in patients supported with continuous flow left ventricular assist devices: Is it time for a paradigm shift in management?

BACKGROUND

De novo aortic insufficiency (AI) following continuous flow left ventricular assist device (CF-LVAD) implantation is a common complication. Traditional early management utilizes speed augmentation to overcome the regurgitant flow in an attempt to augment net forward flow, but this strategy increases the aortic transvalvular gradient which predisposes the patient to progressive aortic valve pathology and may have deleterious effects on aortic shear stress and right ventricular (RV) function.

MATERIALS AND METHODS

We employed a closed-loop lumped-parameter mathematical model of the cardiovascular system including the four cardiac chambers with corresponding valves, pulmonary and systemic circulations, and the LVAD. The model is used to generate boundary conditions which are prescribed in blood flow simulations performed in a three-dimensional (3D) model of the ascending aorta, aortic arch, and thoracic descending aorta. Using the models, impact of various patient management strategies, including speed augmentation and pharmacological treatment on systemic and pulmonary (PA) vasculature, were investigated for four typical phenotypes of LVAD patients with varying degrees of RV to PA coupling and AI severity.

RESULTS

The introduction of mild/moderate or severe AI to the coupled RV and pulmonary artery at a speed of 5,500 RPM led to a reduction in net flow from 5.4 L/min (no AI) to 4.5 L/min (mild/moderate) to 2.1 L/min (severe). RV coupling ratio (Ees/Ea) decreased from 1.01 (no AI) to 0.96 (mild/moderate) to 0.76 (severe). Increasing LVAD speed to 6,400 RPM in the severe AI and coupled scenario, led to a 42% increase in net flow and a 16% increase in regurgitant flow (RF) with a nominal decrease of 1.6% in RV myocardial oxygen consumption (MVO2). Blood pressure control with the coupled RV with severe AI at 5,500 RPM led to an 81% increase in net flow with a 15% reduction of RF and an 8% reduction in RV MVO2. With an uncoupled RV, the introduction of mild/moderate or severe AI at a speed of 5,500 RPM led to a reduction in net flow from 5.0 L/min (no AI) to 4.0 L/min (mild/moderate) to 1.8 L/min (severe). Increasing the speed to 6,400 RPM with severe AI and an uncoupled RV increased net flow by 45%, RF by 15% and reduced RV MVO2 by 1.1%. For the uncoupled RV with severe AI, blood pressure control alone led to a 22% increase in net flow, 4.2% reduction in RF, and 3.9% reduction in RV MVO2; pulmonary vasodilation alone led to a 18% increase in net flow, 7% reduction in RF, and 26% reduction in RV MVO2; whereas, combined BP control and pulmonary vasodilation led to a 113% increase in net flow, 20% reduction in RF and 31% reduction in RV MVO2. Compared to speed augmentation, blood pressure control consistently resulted in a reduction in WSS throughout the proximal regions of the arterial system.

CONCLUSION

Speed augmentation to overcome AI in patients supported by CF-LVAD appears to augment flow but also increases RF and WSS in the aorta, and reduces RV MVO2. Aggressive blood pressure control and pulmonary vasodilation, particularly in those patients with an uncoupled RV can improve net flow with more advantageous effects on the RV and AI RF.

Accuracy of Swan‒Ganz catheterization‐based assessment of right ventricular function: Validation study using high‐fidelity micromanometry‐derived values as reference

Right ventricular (RV) function critically affects the outcomes of patients with pulmonary hypertension (PH). Pressure wave analysis using Swan‒Ganz catheterization (SG‐cath) allows for the calculation of indices of RV function. However, the accuracy of these indices has not been validated. In the present study, we calculated indices of systolic and diastolic RV functions using SG‐cath‐derived pressure recordings in patients with suspected or confirmed PH. We analyzed and validated the accuracies of three RV indices having proven prognostic values, that is, end‐systolic elastance (Ees)/arterial elastance (Ea), β (stiffness constant), and end‐diastolic elastance (Eed), using high‐fidelity micromanometry‐derived data as reference. We analyzed 73 participants who underwent SG‐cath for the diagnosis or evaluation of PH. In this study, Ees/Ea was calculated via the single‐beat pressure method using [1.65 × (mean pulmonary arterial pressure) − 7.79] as end‐systolic pressure. SG‐cath‐derived Ees/Ea, β, and Eed were 0.89 ± 0.69 (mean ± standard deviation), 0.027 ± 0.002, and 0.16 ± 0.02 mmHg/ml, respectively. The mean differences (limits of agreement) between SG‐cath and micromanometry‐derived data were 0.13 (0.99, −0.72), 0.002 (0.020, −0.013), and 0.04 (0.20, −0.12) for Ees/Ea, β, and Eed, respectively. The intraclass correlation coefficients of the indices derived from the two catheterizations were 0.76, 0.71, and 0.57 for Ees/Ea, β, and Eed, respectively. In patients with confirmed or suspected PH, SG‐cath‐derived RV indices, especially Ees/Ea and β, exhibited a good correlation with micromanometry‐derived reference values.

Utility of Real-Time Three-Dimensional Echocardiography for the Assessment of Right Ventricular Morphology and Function in Large Animal Models

Real-time three-dimensional echocardiography (RT3DE) enables a noninvasive assessment of right ventricular (RV) morphology. However, no study has evaluated the relationship between RV function obtained by RT3DE and RV pressure-volume loops. This hypothesis-driven, experimental study aimed to assess the utility of RT3DE in the evaluation of RV morphology and function. Ten anesthetized beagle dogs sequentially underwent dobutamine infusion, acute infusion of lactated Ringer’s solution, and furosemide administration to alter RV contractility and loading conditions. RV pressure-volume loop-derived hemodynamic measurements and echocardiography, including two-dimensional speckle-tracking echocardiography and RT3DE, were performed in each study protocol. Bland−Altman analysis showed strong agreement in RV volume, ejection fraction, and stroke volume obtained by right heart catheterization and RT3DE. Multiple regression analyses revealed that the peak myocardial velocity of the lateral tricuspid annulus (RV s’) and global RV longitudinal strain rate were significantly associated with end-systolic elastance (adjusted r2 = 0.66, p < 0.001). RV s’, RV free wall longitudinal strain, and RT3DE-derived stroke volume/end-systolic RV volume ratio were associated with RV pressure-volume loops-derived end-systolic/arterial elastance ratio (adjusted r2 = 0.34, p < 0.001). RT3DE could detect the changes in catheterization-derived RV volume with a strong agreement and might be useful in estimating RV-pulmonary arterial coupling.

Pressure-based estimation of right ventricular ejection fraction

AIMS

A method for estimating right ventricular ejection fraction (RVEF) from RV pressure waveforms was recently validated in an experimental model. Currently, cardiac magnetic resonance imaging (MRI) is the clinical reference standard for measurement of RVEF in pulmonary arterial hypertension (PAH). The present study was designed to test the hypothesis that the pressure-based method can detect clinically significant reductions in RVEF as determined by cardiac MRI in patients with PAH.

METHODS AND RESULTS

RVEF estimates derived from analysis of RV pressure waveforms recorded during right heart catheterization (RHC) in 25 patients were compared with cardiac MRI measurements of RVEF obtained within 24 h. Three investigators blinded to cardiac MRI results independently performed pressure-based RVEF estimation with the mean of their results used for comparison. Linear regression was used to assess correlation, and a receiver operator characteristic (ROC) curve was derived to define ability of the pressure-based method to detect a maladaptive RV response, defined as RVEF <35% on cardiac MRI. In 23 patients, an automated adaptation of the pressure-based RVEF method was also applied as proof of concept for beat-to-beat RVEF monitoring. The study cohort was comprised of 16 female and 9 male PAH patients with an average age of 53 ± 13 years. RVEF measured by cardiac MRI ranged from 16% to 57% (mean 37.7 ± 11.6%), and estimated RVEF from 15% to 54% (mean 36.2 ± 11.2%; P = 0.6). Measured and estimated RVEF were significantly correlated (r2  = 0.78; P < 0.0001). ROC curve analysis demonstrated an area under the curve of 0.94 ± 0.04 with a sensitivity of 81% and specificity of 85% for predicting a maladaptive RV response. As a secondary outcome, with the recognized limitation of non-coincident measures, Bland-Altman analysis was performed and indicated minimal bias for estimated RVEF (-1.5%) with limits of agreement of ± 10.9%. Adaptation of the pressure-based estimation method to provide beat-to-beat RVEF also demonstrated significant correlation between the median beat-to-beat value over 10 s with cardiac MRI (r2  = 0.66; P < 0.001), and an area under the ROC curve of 0.94 ± 0.04 (CI = 0.86 to 1.00) with sensitivity and specificity of 78% and 86%, respectively, for predicting a maladaptive RV response.

CONCLUSIONS

Pressure-based estimation of RVEF correlates with cardiac MRI and detects clinically significant reductions in RVEF. Study results support potential utility of pressure-based RVEF estimation for assessing the response to diagnostic or therapeutic interventions during RHC.

Invasive Right Ventricular Pressure-Volume Analysis: Basic Principles, Clinical Applications, and Practical Recommendations

Right ventricular pressure-volume (PV) analysis characterizes ventricular systolic and diastolic properties independent of loading conditions like volume status and afterload. While long-considered the gold-standard method for quantifying myocardial chamber performance, it was traditionally only performed in highly specialized research settings. With recent advances in catheter technology and more sophisticated approaches to analyze PV data, it is now more commonly used in a variety of clinical and research settings. Herein, we review the basic techniques for PV loop measurement, analysis, and interpretation with the aim of providing readers with a deeper understanding of the strengths and limitations of PV analysis. In the second half of the review, we detail key scenarios in which right ventricular PV analysis has influenced our understanding of clinically relevant topics and where the technique can be applied to resolve additional areas of uncertainty. All told, PV analysis has an important role in advancing our understanding of right ventricular physiology and its contribution to cardiovascular function in health and disease.

Sex and gender in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare disease characterised by pulmonary vascular remodelling and elevated pulmonary pressure, which eventually leads to right heart failure and death. Registries worldwide have noted a female predominance of the disease, spurring particular interest in hormonal involvement in the disease pathobiology. Several experimental models have shown both protective and deleterious effects of oestrogens, suggesting that complex mechanisms participate in PAH pathogenesis. In fact, oestrogen metabolites as well as receptors and enzymes implicated in oestrogen signalling pathways and associated conditions such as BMPR2 mutation contribute to PAH penetrance more specifically in women. Conversely, females have better right ventricular function, translating to a better prognosis. Along with right ventricular adaptation, women tend to respond to PAH treatment differently from men. As some young women suffer from PAH, contraception is of particular importance, considering that pregnancy in patients with PAH is strongly discouraged due to high risk of death. When contraception measures fail, pregnant women need a multidisciplinary team-based approach. This article aims to review epidemiology, mechanisms underlying the higher female predominance, but better prognosis and the intricacies in management of women affected by PAH.

Unmasking right ventricular-arterial uncoupling during fluid challenge in pulmonary hypertension

BACKGROUND

Patients with pulmonary hypertension (PH) frequently show preserved right ventricular (RV) function at rest. However, volume challenge may uncover pending RV dysfunction. We aimed to assess the physiological and prognostic impact of RV-pulmonary arterial (RV-PA) uncoupling during volume challenge in patients with precapillary PH.

METHODS

We prospectively assessed 32 patients with PH (pulmonary arterial hypertension, n = 27; inoperable chronic thromboembolic disease, n = 5) and 4 controls using invasive pressure-volume (PV) catheterization. PV loops were recorded during preload reduction (balloon occlusion of inferior vena cava; baseline) and acute volume loading (200 ml saline in 20 s). Contractility (multi-beat end-systolic elastance [Ees]), arterial elastance (Ea), and RV-PA coupling (Ees/Ea) were obtained at baseline and at maximum volume loading (MVL).

RESULTS

Median [interquartile range] time to MVL was 19 [18-22] s. Ees/Ea significantly declined from baseline (0.89 [0.69-1.23]) to MVL (0.16 [0.12-0.34]; p < 0.001) in patients with PH but remained stable in controls (baseline: 1.08 [0.94-1.80]; MVL: 1.01 [0.80-2.49]; p = 0.715). The same pattern was observed for Ees, while Ea remained unchanged. The percent decline of RV-PA coupling (ΔEes/Ea) during fluid challenge was significantly associated with pulmonary resting hemodynamics, RV ejection fraction (RVEF), and RV end-diastolic volume. Kaplan-Meier analysis revealed that patients with PH who had a smaller ΔEes/Ea (<-65%) had a significantly better prognosis (log-rank p = 0.0389). In multivariate Cox regression analysis, clinical worsening was predicted by ΔEes/Ea (hazard ratio: 0.96 [95% confidence interval: 0.93-1.00]) and RVEF (hazard ratio: 0.95 [95% confidence interval: 0.92-0.98]).

CONCLUSIONS

Assessment of PV loops during fluid challenge uncovers exhausted RV coupling reserve with severely reduced contractility in PH. RV-PA uncoupling during volume challenge can be predicted by pulmonary resting hemodynamics and RVEF. RV-PA uncoupling during fluid challenge and RVEF (as a noninvasive correlate) are predictors of clinical worsening.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT03403868 (January 19, 2018).

The physiologic basis of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare dyspnea-fatigue syndrome caused by a progressive increase in pulmonary vascular resistance (PVR) and eventual right ventricular (RV) failure. In spite of extensive pulmonary vascular remodeling, lung function in PAH is generally well preserved, with hyperventilation and increased physiologic dead space, but minimal changes in lung mechanics and only mild to moderate hypoxemia and hypocapnia. Hypoxemia is mainly caused by a low mixed venous PO₂ from a decreased cardiac output. Hypocapnia is mainly caused by an increased chemosensitivity. Exercise limitation in PAH is cardiovascular rather than ventilatory or muscular. The extent of pulmonary vascular disease in PAH is defined by multipoint pulmonary vascular pressure-flow relationships with a correction for hematocrit. Pulsatile pulmonary vascular pressure-flow relationships in PAH allow for the assessment of RV hydraulic load. This analysis is possible either in the frequency-domain or in the time-domain. The RV in PAH adapts to increased afterload by an increased contractility to preserve its coupling to the pulmonary circulation. When this homeometric mechanism is exhausted, the RV dilates to preserve flow output by an additional heterometric mechanism. Right heart failure is then diagnosed by imaging of increased right heart dimensions and clinical systemic congestion signs and symptoms. The coupling of the RV to the pulmonary circulation is assessed by the ratio of end-systolic to arterial elastances, but these measurements are difficult. Simplified estimates of RV-PA coupling can be obtained by magnetic resonance or echocardiographic imaging of ejection fraction.

The Right Ventricular-Pulmonary Arterial Coupling and Diastolic Function Response to Therapy in Pulmonary Arterial Hypertension

BACKGROUND

Multiparametric risk assessment is used in pulmonary arterial hypertension (PAH) to target therapy. However, this strategy is imperfect as most patients remain in intermediate or high risk after initial treatment with low risk being the goal. Metrics of right ventricular (RV) adaptation are promising tools that may help refine our therapeutic strategy.

RESEARCH QUESTION

Does RV adaptation predict therapeutic response over time?

STUDY DESIGN AND METHODS

We evaluated 52 incident treatment naïve patients with advanced PAH by catheterization and cardiac imaging longitudinally at baseline, follow-up 1 (∼3 mo.) and follow-up 2 (∼18 mo.). All patients were placed on goal-directed therapy with parenteral treprostinil and/or combination therapy with treatment escalation if functional class I-II was not achieved. Therapeutic response was evaluated at follow-up 1 as non-responders (died) or responders and again at follow-up 2 as super-responders (low risk) or partial-responders (high/intermediate risk). Multiparametric risk was based on a simplified ERS/ESC guideline score. RV adaptation was evaluated with the single-beat coupling ratio (Ees/Ea) and diastolic function with diastolic elastance (Eed). Data are expressed as mean±SD or odds ratio [95%CI].

RESULTS

Nine patients (17%) were non-responders. PAH-directed therapy improved ERS low risk from 1 (2%) at baseline to 23 (55%) at follow-up 2. Ees/Ea at presentation was non-significantly higher in responders (0.9±0.4) versus non-responders (0.6±0.4, p=0.09) but was unable to predict super-responder status at follow-up 2 (odds ratio 1.40 [0.28-7.0], p=0.84). Baseline RVEF and change in Eed successfully predicted super-responder status at follow-up 2 (odds ratio 1.15 [1.0-1.27], p=0.009 and 0.29 [0.86-0.96], p=0.04, respectively).

INTERPRETATION

In patients with advanced PAH, RV-PA coupling could not discriminate irreversible RV failure (non-responders) at presentation but showed a late trend to improvement by follow-up 2. Early change in Eed and baseline RVEF were the best predictors of therapeutic response.

Ventricular-vascular coupling is predictive of adverse clinical outcome in paediatric pulmonary arterial hypertension

Aims

Ventricular–vascular coupling, the ratio between the right ventricle’s contractile state (E_es) and its afterload (E_a), may be a useful metric in the management of paediatric pulmonary arterial hypertension (PAH). In this study we assess the prognostic capacity of the ventricular–vascular coupling ratio (E_es/E_a) derived using right ventricular (RV) pressure alone in children with PAH.

Methods

One hundred and thirty paediatric patients who were diagnosed with PAH via right heart catheterisation were retrospectively reviewed over a 10-year period. Maximum RV isovolumic pressure and end-systolic pressure were estimated using two single-beat methods from Takeuchi et al (E_es/E_a_(Takeuchi)) and from Kind et al (E_es/E_a_(Kind)) and used with an estimate of end-systolic pressure to compute ventricular–vascular coupling from pressure alone. Patients were identified as either idiopathic/hereditary PAH or associated PAH (IPAH/HPAH and APAH, respectively). Haemodynamic data, clinical functional class and clinical worsening outcomes—separated into soft (mild) and hard (severe) event categories—were assessed. Adverse soft events included functional class worsening, syncopal event, hospitalisation due to a proportional hazard-related event and haemoptysis. Hard events included death, transplantation, initiation of prostanoid therapy and hospitalisation for atrial septostomy and Pott’s shunt. Cox proportional hazard modelling was used to assess whether E_es/E_a was predictive of time-to-event.

Results

In patients with IPAH/HPAH, E_es/E_a_(Kind) and E_es/E_a_(Takeuchi) were both independently associated with time to hard event (p=0.003 and p=0.001, respectively) and when adjusted for indexed pulmonary vascular resistance (p=0.032 and p=0.013, respectively). Neither E_es/E_a_(Kind) nor E_es/E_a_(Takeuchi) were associated with time to soft event. In patients with APAH, neither E_es/E_a_(Kind) nor E_es/E_a_(Takeuchi) were associated with time to hard event or soft event.

Conclusions

E_es/E_a derived from pressure alone is a strong independent predictor of adverse outcome and could be a potential powerful prognostic tool for paediatric PAH.

Role of cardiovascular magnetic resonance in pediatric pulmonary hypertension-novel concepts and imaging biomarkers

Pulmonary hypertension (PH) in children is a heterogenous disease of the small pulmonary arteries characterized by a progressive increase in pulmonary vascular resistance. Despite adequate medical therapy, long-term pressure overload is frequently associated with a progressive course leading to right ventricular failure and ultimately death. Invasive hemodynamic assessment by cardiac catheterization is crucial for initial diagnosis, risk stratification and therapeutic strategy. Although echocardiography remains the most important imaging modality for the assessment of right ventricular function and pulmonary hemodynamics, cardiovascular magnetic resonance (CMR) has emerged as a valuable non-invasive imaging technique that enables comprehensive evaluation of biventricular performance, blood flow, morphology and the myocardial tissue. In this review, we summarize the principles and applications of CMR in the evaluation of pediatric PH patients and present an update about novel CMR based concepts and imaging biomarkers that may provide further diagnostic, therapeutic and prognostic information.

Defining end-systolic pressure for single-beat estimation of right ventricle-pulmonary artery coupling: simple… but not really

Surrogates of right ventricle (RV) end-systolic pressure (ESP) used to determine RV-pulmonary artery coupling vary across studies. ESP using point of maximal time varying elastance provides most accurate estimate of actual ESP. https://bit.ly/3xuqX3B.