Resting myocardial blood flow (MBFrest) and myocardial flow reserve (MFR) may improve prognostic assessment beyond left ventricular ejection fraction (LVEF). A large cohort study published in the European Heart Journal evaluated 8,089 consecutive patients who underwent Rb-82 positron emission tomography (PET) stress/rest myocardial perfusion imaging between 2019 and 2024.

The median follow-up was 519 days (IQR: 186–916). During this time, 466 patients died and 819 were hospitalized for heart failure (HF). Both high MBFrest and low MFR independently predicted the composite endpoint of all-cause mortality or HF hospitalization. Hazard ratios reached 1.39 (95% CI: 1.18–1.63) for high MBFrest and 1.70 (95% CI: 1.41–2.04) for low MFR. Prognostic strength increased across the LVEF spectrum. At 40%, 50%, 60%, and 70% LVEF, hazard ratios for high versus low MBFrest were 1.24, 1.61, 1.97, and 2.46, respectively. For low versus high MFR, hazard ratios were 1.57, 2.06, 2.59, and 3.13, respectively. Across constant MFR values, a higher MBFrest consistently carried a greater risk of adverse outcomes.

High MBFrest and low MFR provided prognostic value beyond EF. Both measures identified patients at high risk of death or heart failure hospitalization, especially when EF was preserved.