Background: Cardiac power output at rest (CPO) is a known predictor of worse clinical outcome in various domains of heart failure (HF). However, the prognostic utility of CPO at rest in transcatheter edge-to-edge-repair (TEER) has never been tested.

Objective: To assess the impact of CPO at rest on mortality in chronic HF patients with severe mitral regurgitation (MR) undergoing TEER.

Method: Consecutive patients with chronic HF (left ventricular systolic ejection fraction ≤ 50% from any cause) with severe MR who underwent TEER were included and followed prospectively. Primary endpoint was defined as all-cause mortality during a median follow-up period of 20±11 months. CPO at rest was calculated as: [Cardiac output * mean arterial pressure] * K (conversion factor 2.22 × 10-3) = W. Receiver operator characteristic (ROC) analysis was used to determine discriminative capacity of CPO at rest. Kaplan-Meier estimate was used for survival analysis. A multivariable Cox proportional-hazards regression analysis was performed to identify independent risk factors for all-cause mortality.

Results: 230 patients (median age 77 years (interquartile range (IQR) 71-81years, 60.9% male) at high operative risk (LogEuro-SCORE 18%, IQR 12-29%) were enrolled. Median CPO at rest was 0.69 W (IQR 0.55-0.85W). At long-term follow-up, 86 patients died (37.4%). ROC curve analysis demonstrated that CPO at rest was associated with an area under the curve of 0.62 (95% confidence interval (CI) 0.55-0.70; p=0.01). A CPO at rest threshold of 0.51 W was associated with 54% sensitivity and 88.9% specificity for all-cause mortality. All-cause mortality was significantly higher in patients with CPO ≤0.51 W compared to those with CPO at rest >0.51 W (54.3% vs. 34.4%; log-rank p=0.02). In Cox regression analysis CPO at rest was an independent predictor for all-cause mortality (hazard ratio 0.13; 95% CI 0.04 to 0.46; p=0.002).