Comparing planned versus ad hoc coronary microvascular assessment: Early findings from the Coronary Microvascular Disease Registry

Background: Coronary microvascular dysfunction (CMD) is an etiology for angina with non-obstructive coronary disease. However, the initial adoption of CMD assessment, whether planned or conducted ad hoc, is limited. We characterize planned and ad hoc CMD assessments and highlight evolving trends of a CMD referral center. Methods: We analyzed outpatient data from the Coronary Microvascular Disease Registry from 2021 to 2023. Patients were categorized into planned or ad hoc CMD assessment groups, and baseline characteristics, hospital stay, medications, and physiological measurements were compared. Secondary analysis evaluated a CMD referral center's evolution. Results: Of 101 included outpatients, 67.3 % underwent ad hoc procedures and 32.7 % planned procedures. Average age was 63.1 +/- 10.1 years. The planned procedure group was 87.9% female, and the ad hoc procedure group was 51.5 % female. There were no significant differences in index of microvascular resistance or coronary flow reserve between groups. Hospital stay duration was <1 day for both groups, and neither reported complications. Ad hoc patients were more frequently prescribed aspirin before (64.7 % vs. 36.4 %, p = 0.007) and after the procedure (66.2 % vs. 39.4%, p = 0.01). CMD rates were higher for planned procedures (30.3 % vs. 10.3 %, p = 0.01). We observed that CMD referral centers have more planned procedures and a higher rate of positive results over time. Conclusion: CMD referral centers'planned procedures, and subsequent positive cases, increased over time. This emphasizes the importance of planned procedures, appropriate patient selection, and increased awareness of CMD among healthcare providers. Clinical trial registration: Coronary Microvascular Disease (CMD) Registry, NCT05960474, https://clinicaltrials.gov/ study/NCT05960474