Standard cardiac PET stress tests may miss a clinically important group of patients at elevated heart risk. Researchers analyzed over 6,600 patients with normal perfusion scans and found that measuring blood flow specifically to the inner heart layer — the subendocardium — identified nearly 900 patients whose risk of heart attack, death, or heart failure hospitalization was 41% higher than those with truly normal results. This subendocardial myocardial flow reserve metric captured risk that conventional transmural flow measurements missed entirely. The findings suggest cardiologists could refine risk stratification and potentially intervene earlier in patients currently reassured by a normal stress test result.
