Role of the right ventricular contractile reserve during low-load exercise in predicting heart failure readmission

Background: Exercise intolerance in patients with heart failure (HF) increases HF-associated readmission, and right ventricular (RV) contractile reserve assessed by low-load exercise stress echocardiography (ESE) is associated with exercise intolerance. This study investigated the impact of RV contractile reserve evaluated by low-load ESE on HF readmission.

Methods: We prospectively examined 81 consecutive patients hospitalized for HF who underwent low-load ESE under a stabilized HF condition between May 2018 and September 2020. We performed a 25-W low-load ESE and defined RV contractile reserve as the increment in RV systolic velocity (RV s'). The primary outcome was hospital readmission. Incremental values of the change in RV s' over a readmission risk (RR) score were analyzed using the receiver operating characteristic (ROC) area under the curve; internal validation using bootstrapping was performed. The association between RV contractile reserve and HF readmission was illustrated with the Kaplan-Meier curve.

Results: Eighteen (22 %) patients were readmitted due to worsening HF during the observation period (median 15.6 months). The cut-off value of 0.68 cm/s for the change in RV s' to predict HF readmission with the ROC curve analysis indicated good sensitivity (100 %) and specificity (76.2 %). The discriminatory ability for HF readmission was significantly improved by adding the change in RV s' to the RR score (p = 0.006), and the c-statistic using the bootstrap method was 0.92. The cumulative survival rate free of HF readmission was significantly lower in patients with reduced-RV contractile reserve (log-rank test, p < 0.001).

Conclusions: The change in RV s' during low-load exercise had an incremental prognostic value for predicting HF readmission. The results demonstrated the loss of RV contractile reserve assessed by low-load ESE was associated with HF readmission.