Abstract Body (Do not enter title and authors here): Introduction: Assessment of invasive hemodynamics is a critical aspect of heart failure (HF) management influencing treatment decisions. However, standard metrics including intracardiac filling pressures and cardiac output do not consistently predict clinical outcomes. The myocardial performance score (MPS) is a novel hemodynamic parameter that combines myocardial power and efficiency into a single variable. We aimed to evaluate the prognostic significance of MPS and assess whether it can improve risk stratification compared to traditional measures.

Methods: All patients who underwent isolated right heart catheterization for chronic, or acute on chronic HF between 2013-2019 at our institution were retrospectively analyzed. MPS is calculated as [aortic pulsatility index (API) x cardiac power output (CPO)]/2. The primary outcome was a composite endpoint of death or need for left ventricular assist device or heart transplant over a two-year period. MPS thresholds of 0.5 and 1.0 were selected from prior analyses showing declining efficiency less than 0.5 in addition to balanced power and efficiency greater than 1.0. Kaplan-Meier curves were calculated with statistical significance determined by log-rank tests.

Results: A total of 709 patients (60±14 years; 54% male) were included, of which 102 (14%) had an MPS<0.5, 169 (24%) had an MPS between 0.5-1.0, and 438 (62%) had an MPS≥1.0. Of the 607 patients with an MPS≥0.5, 379 (62%) demonstrated freedom from the composite endpoint compared to 37 (36%) patients with an MPS<0.5 (p<0.0001). An intermediate MPS (0.5≤MPS<1.0) conveyed significantly greater freedom compared to patients with a low MPS<0.5 (57% vs 36%; p<0.001), yet lower freedom compared to those with a high MPS≥1.0 (57% vs. 66%, p<0.05). An MPS<0.5 demonstrated superior risk stratification with an odds ratio for the composite endpoint at two years of 3.1 compared to 1.8 for pulmonary capillary wedge pressure>15 mmHg and cardiac index<2.0 L/min/m² estimated by Fick equation or thermodilution (Figure).

Conclusions: MPS is a novel, advanced hemodynamic measurement that outperforms current invasive hemodynamic parameters in accurately predicting long-term clinical outcomes in all patients with heart failure.