Single-beat right ventricular-pulmonary artery coupling and residual heart failure in patients with a HeartMate 3 left ventricular assist device.

BACKGROUND

Contemporary left ventricular assist devices (LVADs) improve survival, yet residual heart failure (HF) remains despite optimized device support. The extent to which right ventricular (RV)-pulmonary artery (PA) interaction, measured by single-beat elastance-based indices, identifies residual risk is unknown.

METHODS

We studied 70 adults implanted with HeartMate3 LVADs (2018-2022) who underwent pre-discharge right heart catheterization after echocardiographic and invasive LVAD optimization. Using a single-beat method, RV end-systolic elastance (Ees), PA effective arterial elastance (Ea), and the Ees:Ea ratio (RV-PA coupling) were derived from high-fidelity pressure waveforms. Associations between these indices and surrogates of residual HF (cardiac output [CO] at discharge, need for high-dose outpatient diuretics, and 3-month 6-minute walking distance [6MWD]) were evaluated using multivariable regressions.

RESULTS

Despite optimized LVAD support, patients demonstrated preserved RV Ees (0.40 ± 0.19mmHg/ml), elevated PA Ea (0.54 ± 0.21 mmHg/ml) and reduced Ees:Ea ratio (0.78 ± 0.36), consistent with RV-PA uncoupling. Higher PA Ea independently associated with lower CO and greater likelihood of high-dose diuretic use, while impaired RV-PA coupling (lower Ees:Ea) was the only hemodynamic parameter associated with reduced 6MWD. Traditional RV indices, including PAPi and CVP-to-wedge ratio, were not associated with outcomes.

CONCLUSION

Single-beat RV-PA elastance metrics identify residual HF phenotypes in clinically optimized HM3 recipients not captured by standard right-sided indices. If prospectively validated, incorporating RV Ees, PA Ea ("flow obstruction") and Ees:Ea ("energy inefficiency") into pre-discharge assessment may be used to refine risk stratification and inform device-directed and pulmonary vascular interventions during LVAD.