Multi-Beat Right Ventricular-Arterial Coupling Predicts Clinical Worsening in Pulmonary Arterial Hypertension

Background Although right ventricular (RV) to pulmonary arterial (RV-PA) coupling is considered the gold standard in assessing RV dysfunction, its ability to predict clinically significant outcomes is poorly understood. We assessed the ability of RV-PA coupling, determined by the ratio of multi-beat (MB) end-systolic elastance (Ees) to effective arterial elastance (Ea), to predict clinical outcomes. Methods and Results Twenty-six subjects with pulmonary arterial hypertension (PAH) underwent same-day cardiac magnetic resonance imaging, right heart catheterization, and RV pressure-volume assessment with MB determination of Ees/Ea. RV ejection fraction (RVEF), stroke volume/end-systolic volume, and single beat-estimated Ees/Ea were also determined. Patients were treated with standard therapies and followed prospectively until they met criteria of clinical worsening (CW), as defined by ≥10% decline in 6-minute walk distance, worsening World Health Organization (WHO) functional class, PAH therapy escalation, RV failure hospitalization, or transplant/death. Subjects were 57±14 years, largely WHO class III (50%) at enrollment, with preserved average RV ejection fraction (RVEF) (47±11%). Mean follow-up was 3.2±1.3 years. Sixteen (62%) subjects met CW criteria. MB Ees/Ea was significantly lower in CW subjects (0.7±0.5 versus 1.3±0.8, P=0.02). The optimal MB Ees/Ea cut-point predictive of CW was 0.65, defined by ROC (AUC 0.78, P=0.01). MB Ees/Ea below this cut-point was significantly associated with time to CW (hazard ratio 5.1, P=0.001). MB Ees/Ea remained predictive of outcomes following multivariate adjustment for timing of PAH diagnosis and PAH diagnosis subtype. Conclusions RV-PA coupling as measured by MB Ees/Ea has prognostic significance in human PAH, even in a cohort with preserved RVEF.

Single-Beat Estimation of Right Ventricular Contractility and Its Coupling to Pulmonary Arterial Load in Patients With Pulmonary Hypertension

Background

An accurate assessment of intrinsic right ventricular (RV) contractility and its relation to pulmonary arterial load is essential for the management of pulmonary hypertension. The pressure‐volume relationship with load manipulation is the gold standard assessment used for this purpose, but its clinical application has been hindered by the lack of a single‐beat method that is valid for the human RV. In the present study, we sought to validate a novel single‐beat method to estimate the preload recruitable stroke work (PRSW) and its derivative for ventriculoarterial coupling in the human RV.

Methods and Results

A novel single‐beat slope of the PRSW relationship (M_sw) was derived by calculating the mean ejection pressure when the end‐systolic volume was equal to volume‐axis intercept of the PRSW relationship. In addition, by using a mathematical transformation of the equation representing the linearity of the PRSW relationship, a novel index for ventriculoarterial coupling, M_sw/mean ejection pressure, was developed. RV pressure‐volume relationships were measured in 31 patients (including 23 patients with pulmonary hypertension) who were referred for right‐sided heart catheterization. In this cohort, the single‐beat M_sw was strongly correlated with the multiple‐beat M_sw (r=0.91, P<0.0001). Moreover, a significant correlation was observed between the single‐ and multiple‐beat M_sw/mean ejection pressure (r=0.53, P=0.002), with a stronger correlation in those with greater RV systolic pressure (r=0.70, P=0.003).

Conclusions

The novel single‐beat approach provided an accurate estimation of indexes for the PRSW relationship and ventriculoarterial coupling. It may be particularly useful in assessing RV adaptation to increased pressure overload.

Distinct Hemodynamic Changes After Interventional Mitral Valve Edge-to-Edge Repair in Different Phenotypes of Heart Failure: An Integrated Hemodynamic Analysis

Background

Percutaneous mitral valve edge‐to‐edge repair (pMVR) with a MitraClip is beneficial for the clinical symptoms of patients irrespective of the ejection fraction (EF). Nevertheless, the consequences on hemodynamics are poorly understood. Therefore, we used data from noninvasive pressure‐volume loops to investigate the left ventricular (LV) remodeling of patients after pMVR dependent on their baseline EF.

Methods and Results

In 130 patients with successful pMVR, the end‐diastolic pressure‐volume relationship (EDPVR) and end‐systolic pressure‐volume relationship were estimated noninvasively from echocardiographic data. We compared EDPVR and end‐systolic pressure‐volume relationship at discharge and follow‐up between patients with a reduced EF (<40%) and patients with a mid‐ranged or preserved EF (≥40%). Reduced EF was present in 71 patients (54%). Mean follow‐up duration was 277±117 days. We observed a significant reduction in degree of mitral regurgitation and an improvement in functional status at follow‐up irrespective of baseline EF. In patients with a mid‐ranged or preserved EF, the EDPVR and end‐systolic pressure‐volume relationship were shifted leftwards, suggesting an improvement in LV function. In contrast, in patients with a reduced EF, EDPVR and end‐systolic pressure‐volume relationship remained stable, although comparison with the baseline data indicates a rightward shift of the EDPVR. This indicates that there is no improvement in LV function after pMVR in patients with reduced EF.

Conclusions

The pMVR is associated with improved clinical symptoms in all patient subgroups. However, it leads to different hemodynamic responses. In patients with mid‐ranged or preserved EF, we found reverse remodeling with reduced LV dilatation and increased contractility. In contrast, in patients with reduced EF, we observed no reverse remodeling and no improvement in LV function.