Abstract 4142037: Age Differences in Patients with Ischemia and Nonobstructive Coronary Arteries

Introduction: Ischemia and nonobstructive coronary arteries (INOCA) is increasingly recognized and encompasses vasomotor disorders such as coronary microvascular dysfunction (CMD) and vasospastic angina (VA). The prevalence of atherosclerotic coronary artery disease increases with age, but the age at the time of diagnosis in patients with INOCA is not well described. Methods: From 2017 to 2024, 221 patients with INOCA underwent invasive coronary physiologic assessment including vasoreactivity testing with acetylcholine provocation, guidewire-based assessment of coronary flow reserve (CFR), index of microcirculatory resistance (IMR), and fractional flow reserve (FFR). Age cut-off of 60 years was selected to create two groups of adequate size. Results: Mean age was 57.7 ± 10.8 years and 158 (71.5%) were females. Older INOCA patients (>60 years old) had higher rates of hypertension and obstructive sleep apnea, but similar rates of hyperlipidemia, diabetes, depression, anxiety, and active smoking compared to younger patients (<60 years old). There were significant differences in medical therapy at baseline with older patients being more likely to receive statin (69.7% vs 54.9%, p=0.024), ACEi/ARB (35.4% vs. 22.1%, p=0.029), or β-blockers (50.5% vs. 35.3%, p=0.022). Increasing age was associated with progressive decrease in CFR (rho=-0.21; R 2 = 0.04; p<0.001), and a progressive increase in IMR (rho=0.35; R 2 = 0.12; p=0.002) (Figure 1). Older INOCA patients had higher rates of CMD (38.4% vs. 21.3%; p=0.005), and myocardial bridging was more frequent in younger patients (14.8% vs. 5.1%; p=0.015) (Figure 2). Conclusion: In our study sample, increasing age was associated with a reduction in CFR and increase in IMR. Older INOCA patients were more likely to have CMD and less likely to have myocardial bridging compared to younger patients.