Association between 82Rb positron emission tomography-derived regional myocardial blood flow, severity of angiographic coronary artery stenosis, and mortality in patients with chest pain

Impairment in global myocardial flow reserve (MFR) on rubidium-82 (82Rb) positron emission tomography (PET) stress testing predicts cardiovascular events; however, the relationship between regional coronary artery territory myocardial blood flow (MBF) and invasive coronary angiography is unknown. In this study, patients with acute chest pain who were referred for coronary angiography after abnormal PET stress testing were evaluated. Both global and regional coronary territory stress and rest MBF were derived using 82Rb PET. Coronary artery stenosis severity was assessed using quantitative coronary angiography (QCA) performed within 3 months of PET. A total of 189 patients were followed for a median of 4.1 years. The results showed a weak correlation between regional MFR impairment (<1.7) and stenosis severity in the left descending artery (r = −0.20, P = 0.005), left circumflex artery (r = −0.15, P = 0.042), and right coronary artery (r = −0.26, P < 0.001). In addition, a weak correlation was observed between global MFR and stenosis in any vessel, in both binary and continuous analyses. However, impairment in MFR within any territory was associated with increased all-cause mortality in both unadjusted and adjusted analyses. In conclusion, this is the first large-scale study to examine the relationship between regional coronary territory MBF, coronary artery stenosis severity as assessed using QCA, and mortality. Although coronary territory MFR demonstrated a weak correlation with coronary stenosis severity, impairment in per-territory MFR was significantly associated with increased all-cause mortality, suggesting that mechanisms such as diffuse atherosclerosis and/or microvascular disease may be contributing factors.