Prediction of outcome by 82Rb PET/CT in patients with ischemia and nonobstructive coronary arteries

Background The purpose of this study was to assess the prognostic value of cardiac Rb-82 positron emission tomography (PET)/computed tomography (CT) imaging in patients with myocardial ischemia of nonobstructive coronary arteries (INOCA). Methods We retrospectively evaluated 311 INOCA patients who underwent rest stress Rb-82 PET/CT. Cardiac end points were cardiac death, myocardial infarction, or late coronary revascularization. A parametric survival model was also used to identify how the variables influenced time to event. Results During a median follow-up of 37 months (range 6-108), 23 (7%) cardiac events occurred. In patients with events total perfusion defect (TPD) was higher and myocardial flow reserve (MFR) lower compared to those without events (both P < .001). At multivariable Cox analysis, increased TPD (i.e., >= 5%) and reduced MFR (i.e., < 2) were predictors of events (both P < .001). At Weibull survival analysis, the highest probability of cardiac events and risk acceleration were observed in patients with both increased TPD and reduced MFR. Annualized event rate was higher in patients with reduced MFR compared to those with preserved MFR (P < .001). Conclusion In patients with INOCA, the combined evaluation of myocardial perfusion and coronary vascular function by Rb-82 PET/CT is able to identify those at higher risk of cardiac events.

Automated summary

The study assessed the prognostic value of cardiac Rb-82 positron emission tomography (PET)/computed tomography (CT) imaging in patients with myocardial ischemia of nonobstructive coronary arteries. The results showed that increased total perfusion defect (TPD) and reduced myocardial flow reserve (MFR) were predictors of cardiac events in these patients. The combined evaluation of myocardial perfusion and coronary vascular function by Rb-82 PET/CT can identify patients at higher risk of cardiac events.