Comparison of clinical characteristics between patients with microvascular and epicardial coronary artery spasm

Background Coronary functional abnormalities including both epicardial and microvascular coronary artery spasm represent an important role responsible for myocardial ischemia in patients with angina and nonobstructive coronary artery disease. However, clinical characteristics associated with microvascular spasm (MVS) have not been fully evaluated. Purpose The aim of this study was to assess differences in clinical features between patients with MVS and epicardial coronary spasm. Methods A total of 732 consecutive patients with suspected angina who presented nonobstructive coronary arteries and underwent intracoronary acetylcholine provocation test were retrospectively enrolled in this study. Epicardial coronary spasm was defined as total or subtotal occlusion of epicardial coronary arteries accompanied by chest pain and/or ischemic electrocardiographic changes in response to acetylcholine provocation test. MVS was diagnosed when chest pain and/or ischemic electrocardiographic changes developed after administration of acetylcholine in the absence of epicardial coronary spasm. Clinical characteristics were compared between patients with MVS and epicardial coronary spasm. Results Of all patients, 83 patients (11%) had MVS, 367 (50%) had epicardial coronary spasm, and the other patients (39%) showed neither MVS nor epicardial coronary spasm. Patients with MVS tended to be older (65.6±12.7 vs. 63.0±12.3 years, P=0.088) and were more frequently female (60.2% vs. 41.1%, P=0.0016) in comparison with patients with epicardial coronary spasm. Patients with MVS were less likely to be smokers (8.6% vs. 22.9%, P=0.0018), while there were no significant differences in the other coronary risk factors such as hypertension, dyslipidemia, and diabetes mellitus. Serum uric acid were significantly lower in patients with MVS (4.9±1.1 vs. 5.4±1.3 mg/dl, P=0.0018). Conclusion Our study demonstrated that patients with MVS had distinctive clinical background from those with epicardial coronary spasm, suggesting different mechanisms may involve the development of MVS. Funding Acknowledgement Type of funding source: None

P5538Safety and efficacy of acetylcholine provocation test for diagnosis of vasospastic angina in young patients

Background Vasospastic angina (VSA) is considered as a cause of myocardial infarction with nonobstructive coronary arteries. Given the previous reports of higher incidence of cardiovascular events in young VSA patients, early diagnosis and optimal treatment are important for these patients. While acetylcholine provocation test (ACh test) for VSA diagnosis is well reported, ACh test among young patients is not as commonly performed, therefore its safety and usefulness for this patient subset have not been fully evaluated. Purpose The purpose of this study was to evaluate the safety and the proportion of positive results of ACh test for young patients. Methods Data from patients who underwent ACh test in our institution from May 2012 to September 2018 were retrospectively analyzed. A total of 669 patients were enrolled and divided into 2 groups according to age: Young group (Age≤50, n=106); and Senior group (Age>50, n=563). Results The senior group had a higher incidence of hypertension, dyslipidemia, diabetes mellitus, and coronary artery disease. On the other hand, the young group had a significantly higher incidence of current smoker and tendency of daily alcohol. The rate of positive ACh test was similar, and there were no significant differences in major or minor complications between the 2 groups. Patient characteristics and outcome Young group Senior group p (n=106) (n=563) Age (years) 42.8±7.3 68.0±9.0 <0.001 Male (%) 56.6 52.2 0.407 Current smoker (%) 34.9 15.4 <0.001 Daily alcohol (%) 31.1 22.9 0.070 Hypertension (%) 33.0 66.6 <0.001 Dyslipidemia (%) 50.0 68.4 <0.001 Diabetes (%) 12.3 20.8 0.047 ACh positive (%) 52.8 49.9 0.581 Minor adverse event (%) 4.7 5.9 0.820 Major adverse event (%) 0.9 1.4 1.000 Major adverse event: composite of death, ventricular fibrillation, sustained ventricular tachycardia (VT), myocardial infarction and stroke. Minor adverse event: non-sustained VT and paroxysmal atrial fibrillation. Conclusion ACh provocation test for young patients can be safely performed, and the rate of positive results was similar to that of senior patients. In young patients suspected of having VSA, ACh test should be actively performed to identify optimal medical therapy for prevention of cardiovascular events. Acknowledgement/Funding None