Abstract 17801: Age-Specific Normal Values for Myocardial Blood Flow on 82rb Positron Emission Tomography

Abstract

Introduction: Positron emission tomography (PET) myocardial perfusion imaging (MPI) is utilized to evaluate ischemia along with myocardial blood flow (MBF). The ability to adequately augment blood flow, measured by myocardial blood flow reserve (MBFR), is a measure of overall health of the coronary circulation and associated with lower major adverse cardiovascular events (MACE) and all-cause mortality. The age-specific ranges of MBFR in patients without demonstrable coronary artery disease (CAD) has not been well established. Hypothesis/Aim: To determine the effect of age on MBF and MBFR in a cohort of patients without demonstrable CAD. Methods: Patients who underwent PET MPI studies from 2012-2022 on Siemens PET/CT cameras were included if Summed Stress Score=0, coronary calcium score=0, and left ventricular ejection fraction ≥50%. Those with prior history of MI or coronary intervention, heart/kidney/liver transplant, cirrhosis, or CKD stage IV+ were excluded. MBF was calculated using a net retention model (ImagenQ, Cardiovascular Imaging Technologies, Kansas City, MO) and multivariable linear regression models were developed to predict MBF. Results: Among 3,235 patients (age 59.5+/-12.6 years, 24.2% male) with median rest MBF 0.74 [0.61-0.92] and stress MBF 1.71 [1.41-2.10], MBFR was 2.28 [1.93-2.72]. With increasing age, rest MBF remained fairly stable while stress MBF and MBFR decreased, such that for every 10 years of age, stress MBF decreased by 0.07 [95% CI 0.05-0.08] mL/min/g and MBFR decreased by 0.12 [95% CI 0.11-0.14] after multivariable adjustment. Age-specific predicted MBFR values are documented in the Table. Conclusions: In patients without demonstrable CAD, the MBFR decreases with age. Abnormal MBFR values under 2.0 may be seen in a significant number of older patients.