Introduction:
Quantitative myocardial blood flow (MBF) obtained via Rb82 PET/CT using regadenoson provides the ability to assess ischemia through analysis of stress MBF and coronary flow reserve (CFR), the augmentation of flow expressed as a stress/rest ratio. It is unknown to what extent, if any, age-related changes in arteries (i.e. arterial stiffening, atherosclerosis) impact MBF and, thus, the interpretation of ischemia.
Hypothesis:
MBF values change as a function of age and impact PET interpretation.
Methods:
Patients who underwent PET/CT from May 2013 to April 2015 with normal perfusion images and no history of PCI or CABG were included (n=3329, 1720 women, 1498 men). Rest MBF, stress MBF, and CFR) (mL/min/g) were recorded in all vessels separated by gender and by age <60 or ≥60. Analysis was conducted on individual vessels and global estimates were calculated averaging all vessels. Estimated average median differences between age <60 and ≥60 were adjusted for traditional cardiovascular risk factors (BMI, smoking, diabetes, hypertension, hyperlipidemia, family history).
Results:
Effects of Age on Global MBF Adjusted for Traditional Risk Factors
Conclusions:
In patients ≥60 years of age with normal perfusion imaging, rest MBF increases, stress MBF decreases, and the resultant CFR is decreased, all statistically significant. This may reflect a higher fixed level of vasodilation in older vessels at rest and a more limited ability to vasodilate with stress independent of other CV risk factors. Given the increasing use of PET/CT for ischemia assessment, it is important to recognize expected MBF changes with age to decrease false positive studies and unwarranted invasive testing.
GENDER DIFFERENCES IN MYOCARDIAL BLOOD FLOW IN CARDIAC PET/CT WITH REGADENOSON
