Key result
Patients with MINOCA had a significantly elevated average angiography-based index of microvascular resistance compared to controls (30.5 vs 22.1, p<0.001), indicating microvascular dysfunction.
Why the study?
Data on coronary microvascular dysfunction in MINOCA are scarce, and it is unclear whether it is equally present across all subtypes or differentially identifies specific conditions.
Does coronary microvascular dysfunction, assessed by aIMR, differ between patients with MINOCA and controls, and among different MINOCA subtypes?
Observational (n=92)
No
Does coronary microvascular dysfunction, assessed by aIMR, differ between patients with MINOCA and controls, and among different MINOCA subtypes?
Absolute Event Rate: 30.5% vs 22.1%
p-value: p=<0.001
Coronary microvascular dysfunction is a consistent hallmark across all subtypes of MINOCA and co-localizes with diseased myocardium, suggesting a key pathophysiological role.
MINOCA patients show higher aIMR than controls across subtypes; hypothesis-generating for microvascular dysfunction but should not yet change practice.
INTRODUCTION: Myocardial infarction without obstructive coronary artery disease (MINOCA) is a heterogeneous clinical condition presenting with myocardial necrosis not due to an obstruction of a major coronary artery. Recently, a relevant role of coronary microvascular dysfunction (CMD) in the pathogenesis of MINOCA has been suggested; however, data on this are scarce. Particularly, it is unclear if CMD is equally present in all subtypes of MINOCA or differentially identifies one or more of these conditions. Therefore, the aim of this study was to assess CMD in all three coronary vessels of MINOCA patients, relating it with the clinical subtype. METHODS: We retrospectively assessed coronary microvascular function in all three coronary territories by means of angiography-based index of microvascular resistance (aIMR) in 92 patients (64 with working diagnosis of MINOCA, 28 control patients). To further assess the association of CMD with MINOCA subtypes, MINOCA patients were subdivided according to clinical data in coronary cause (n = 13), takotsubo (n = 13), infiltrative or inflammatory cardiomyopathy (n = 9) or unclear (n = 29). RESULTS: Patients with working diagnosis of MINOCA showed a significantly elevated average aIMR compared to control patients (30.5 ± 7.6 vs. 22.1 ± 5.9, p < 0.001) as a marker of a relevant CMD; these data were consistent in all vessels. Among MINOCA subtypes, no significant difference in average aIMR could be detected between patients with coronary cause (33.2 ± 6.6), takotsubo cardiomyopathy (29.2 ± 6.9), infiltrative or inflammatory cardiomyopathy (28.1 ± 6.8) or unclear cause (30.6 ± 8.5; p = 0.412). Interestingly, aIMR was significantly elevated in the coronary vessel supplying the diseased myocardium compared with other vessels (31.9 ± 11.4 vs. 27.8 ± 8.2, p = 0.049). CONCLUSION: Coronary microvascular dysfunction is a hallmark of all MINOCA subtypes. This study adds to the pathophysiological understanding of MINOCA and sheds light into the role of CMD in MINOCA.
No takes yet. Share an insight, caveat, or question.
Milzi et al. (2023) conducted an observational in Myocardial infarction without obstructive coronary artery disease (MINOCA) (n=92). MINOCA vs. Control patients without ischemia or obstructive coronary artery disease was evaluated on Average angiography-based index of microvascular resistance (aIMR) (p=<0.001). Patients with MINOCA had a significantly elevated average angiography-based index of microvascular resistance compared to controls (30.5 vs 22.1, p<0.001), indicating microvascular dysfunction.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: