Does quantification of myocardial flow reserve using rubidium-82 positron emission tomography facilitate detection of multivessel coronary artery disease?

Abstract

BackgroundRelative myocardial perfusion imaging (MPI) is the standard imaging approach for the diagnosis and prognostic work-up of coronary artery disease (CAD). However, this technique may underestimate the extent of disease in patients with 3-vessel CAD. Positron emission tomography (PET) is also able to quantify myocardial blood flow. Rubidium-82 (82Rb) is a valid PET tracer alternative in centers that lack a cyclotron. The aim of this study was to assess whether assessment of myocardial flow reserve (MFR) measured with 82Rb PET is an independent predictor of severe obstructive 3-vessel CAD. MethodsWe enrolled a cohort of 120 consecutive patients referred to a dipyridamole 82Rb PET MPI for evaluation of ischemia neither with prior coronary artery bypass graft nor with recent percutaneous coronary intervention that also underwent coronary angiogram within 6 months of the PET study. Patients with and without 3-vessel CAD were compared. ResultsAmong patients with severe 3-vessel CAD, MFR was globally reduced (<2) in 88% (22/25). On the adjusted logistic Cox model, MFR was an independent predictor of 3-vessel CAD [.5 unit decrease, HR: 2.1, 95% CI (1.2-3.8); P = .015]. The incremental value of 82Rb MFR over the SSS was also shown by comparing the adjusted SSS models with and without 82Rb MFR (P = .005). Conclusion82Rb MFR is an independent predictor of 3-vessel CAD and provided added value to relative MPI. Clinical integration of this approach should be considered to enhance detection and risk assessment of patients with known or suspected CAD.