Characteristics associated with abnormal dynamic flow in patients with severe obesity undergoing PET myocardial...

To study dynamic flow data in patients with severe obesity undergoing PET myocardial perfusion imaging given that certain dynamic flow parameters are associated with adverse cardiovascular outcomes and can carry prognostic significance.

Cross-sectional study of patients with severe obesity (BMI ≥ 35 kg/m2) who underwent Rb82 stress/rest PET myocardial perfusion imaging(MPI) in 2022-2023. Absolute myocardial blood flow(MBF) in mL/g/min was computed from the dynamic rest and stress images. MFR was calculated as the ratio of stress to rest MBF. Global MFR < 1.7 was considered significantly reduced and a rest MBF > 1.1 mL/g/min was considered elevated. Linear regression was used to investigate an association of patient characteristics with MBF.

Out of 123 patients, 78(63.4%) were male, 38% had reduced MFR, and 30% had an increased rest MBF, whereas 18% had both reduced MFR and increased rest MBF. After adjusting for age and BMI, there was a statistically significant difference in mean rest MBF in female (1.04 mL/g/min; 95%CI 0.96-1.12) versus male (0.85 mL/g/min; 95%CI 0.79-0.91) patients(P = 0.0004). There was a significant association between female sex and rest MBF > 1.1(P = 0.031). Adjusted for sex and BMI, linear regression analysis showed older age was associated with decreasing MFR by 0.14 (95% CI 0.06-0.22) per 10 years of age (P = 0.001).

In a sample of patients with severe obesity undergoing Rb82 PET, there is a high prevalence of reduced MFR and increased rest MBF. Increasing age and female sex are associated with adverse physiologic alterations based on dynamic flow data within this at-risk patient population.