Abstract Body (Do not enter title and authors here): BACKGROUND: Coronary artery spasm (CAS) is a cause of variant angina and is typically diagnosed by intracoronary provocation test. Investigations regarding association between the burden of coronary artery stenosis and the minimum responsive dose of ergonovine (ERG) required for provocation is limited.
METHODS: In this study, 356 patients who underwent the ergonovine (ERG) provocation test and showed CAS between October 2004 and December 2022 were enrolled. Significant CAS was defined as temporary narrowing of ≥70% during the ERG test. Patients were divided into three groups, based on the minimum responsive dose of ERG: E1 group (20ug, n=13), E2 group (40ug, n=53) and E3 group (80ug, n=290).
RESULTS: In patients who were documented with positive intracoronary ERG provocation test, 3.7% responded at the lowest dose (20ug), 14.9% responded at the medium dose (40ug) and 81.5% responded only at the highest dose of ERG (80ug). The baseline characteristics of the patients among the 3 groups were similar, demonstrating no significant difference in the prevalence of hypertension, diabetes mellitus, and dyslipidemia. However, patients who responded at E2 dose showed higher proportion of smokers than E3 dose (E2 34.0% vs. E3 25.9%, p=0.043). E1 group demonstrated the highest proportion of severe stenosis (92.3%), followed by E2 group (90.6%) and E3 group (71.4%) (Figure 1). In addition, incidence of focal CAS and multi-vessel CAS were higher among those who responded to lower doses (focal CAS: 23.1% vs. 20.8% vs. 10.0%; multi-vessel CAS: 61.5% vs.50.9% vs. 36.6%).
CONCLUSION: In patients with chest pain with positive intracoronary ERG provocation test, higher burden of stenotic lesions was found to be more frequent and more susceptible in patients who responded at lower doses of ERG.