Incremental prognostic value of coronary flow reserve derived from SPIM digital positron emission tomography

Abstract

Abstract Introduction Positron emission tomography (PET) myocardial perfusion imaging (MPI) is an established test in the diagnosis and prognosis of patients with cardiac diseases. Silicon photomultiplier (SiPM) digital PET is the latest advancement in this technology with improved detector sensitivity, coincidence time resolution, and spatial resolution, allowing for Sub-milliSievert cardiac PET MPI. Purpose We aimed to assess the independent and incremental prognostic value of SiPM digital PET derived coronary flow reserve (CFR) to clinical and nuclear variables. Methods Consecutive patients who had clinically indicated digital Rubidium PET MPI were included. Rubidium dose was 10–20 mCi according to patient's weight. Patients were followed from the date of imaging to incident major adverse cardiovascular event (MACE: inclusive of all-cause death, myocardial infarction, admission for heart failure and late revascularization – percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) >90 days after imaging). Results The study population consisted of 2,893 patients with clinically indicated PET MPI (mean age 67 (±12), 53% male, 41% Caucasian). Cardiovascular risk factors were prevalent (88% hypertensive, 80% dyslipidemic, 47% diabetics, 18% ever smoking). After a mean follow-up of 8±7 months, 250 patients (8.6%, 10.7 per 1000 person-year) experienced MACE (90 D / 38 MI / 51 PCI / 11 CABG / 113 HF). In nested multivariable cox models, CFR was independently associated with incident MACE (HR 0.38, 95% CI 0.29–0.51, p<0.001) and incrementally improved risk prediction (Harrell's C=0.77, p=0.002). Conclusion Our findings showed that a Sub-milliSievert SiPM digital PET-derived CFR provided incremental value in risk-stratifying patients and identifying those at increased risk of incident outcomes. Funding Acknowledgement Type of funding sources: None.