Abstract 4137449: Diagnostic Yield and Testing Characteristics of an Invasive Coronary Function Testing Program

Background: Angina, ischemia, or myocardial infarction in the absence of obstructive coronary artery disease (ANOCA, INOCA, or MINOCA) is common and underdiagnosed. Invasive coronary function testing (CFT) for microvascular disease through coronary thermodilution and for coronary vasospasm through coronary reactivity testing can provide definitive diagnoses and improve patient quality of life. Here, we describe a single site experience launching a CFT program and present the diagnostic yield and test characteristics of the first 66 patients. Methods: The first 66 patients who underwent invasive CFT at Mass General Hospital after the launch of the program in 2022 were included. Invasive CFT data and clinical characteristics before and after were entered into a registry. We used descriptive statistics to summarize patient characteristics, diagnostic yield and change in management with invasive CFT. We describe the dose-response and safety of incremental doses of acetylcholine. Results: Among 66 patients (mean age 61.73±11.02 years, 56% female), 17 patients underwent testing at the time of an index angiogram and 49 were scheduled after knowledge of coronary anatomy. Reasons for invasive coronary function testing were post-revascularization angina (n=30, 45.5%), ANOCA (n=21, 31.8%), INOCA (n=9, 13.6%), MINOCA (n=4, 6.1%), and heart transplant patients (n=2, 3%). 24 (36.3%) patients underwent coronary thermodilution only, 6 (9.1%) coronary reactivity testing only , and 36 (54.5%) both. CFT resulted in a definitive diagnosis in 45 (68.1%) of participants – 37.9% with coronary vasospasm only, 13.6% with microvascular dysfunction only, and 16.7% with both. There were 21 (31.8%) patients who remained negative after invasive CFT. Invasive CFT led to a change in management in 46 (70%) patients. For example, nitrate, calcium channel blocker and beta blocker prescriptions were modified in 47%, 50%, and 52.3% of patients, respectively. Among 42 patients who underwent coronary reactivity testing by provocation with intracoronary acetylcholine doses of 20, 100, and 200 mcg, there was a dose-response to angina (18.5%, 70.2%, and 95.2%), ischemic ECG changes (11.1%, 75.7%, and 95.2%), and vessel spasm of greater than 90% (3.7%, 27%, and 57.1%). There was only one safety event(PTCA to re-establish flow after spasm). Conclusions: We demonstrate the safe implementation of an invasive coronary function testing program with very high diagnostic yield and impact on management.