Canadian Journal of Cardiology



      Ischemia with non-obstructive coronary artery disease (INOCA) is a common heart condition often overlooked in cardiology practice. There is still under-recognition of this condition, but it is unclear if the referral patterns for invasive testing have changed. We aimed to determine if the prevalence of patients diagnosed with INOCA through invasive testing has changed over time.

      Methods and Results

      A population-based cohort of patients who had their first cardiac angiography for a chest pain syndrome in Alberta between 1999 and 2019 was extracted retrospectively from the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH©) database. A temporal trend analysis was performed to compare patients with INOCA to obstructive coronary artery disease (CAD) and investigate the ratios of these two populations between acute coronary syndrome (ACS) and stable angina (SA), males and females, and males and females with SA and ACS. In our analysis, 121,066 patients were included (26% INOCA, 31% female, mean age 62 years). Patients with INOCA were more likely to be female and associated with stable angina and atrial fibrillation as compared to patients with obstructive CAD (OR=3.29, 95% CI: 3.01, 3.59, p< 0.001; OR=2.62, 95% CI: 2.4, 2.86, p< 0.001; OR=2.21, 95% CI: 1.77, 2.76, p< 0.001, respectively). The percent of INOCA to obstructive CAD ranged between 24.2% and 26.7% in all patients (p < 0.001), 19.4% and 21.4% in patients with ACS (p=0.002), and 30.6% and 37.5% in patients with SA (p < 0.001). Additionally, women had a higher prevalence of INOCA than men, with the percentage of INOCA to obstructive CAD ranging between 17.4% and 20.2% in males and 37.9% and 40.9% in females (p < 0.001; p=0.011, respectively). A similar trend was observed in both males and females with ACS and SA, with the percent of INOCA to obstructive CAD ranging between 14.1% and 15.7% in males with ACS and 31.4% and 33.5% in females with ACS and 27.3% and 29.5% in males with stable angina and 49.7% and 54.6% in females with stable angina. Overall, there was no substantial difference in the percentage of INOCA to obstructive CAD over time.