Data Sheet 1_Coronary microvascular dysfunction mediates in-hospital adverse outcomes in ST-segment elevation myocardial infarction patients without standard modifiable cardiovascular risk factors.docx

BackgroundRecent studies have demonstrated that patients with ST-segment elevation myocardial infarction (STEMI) without standard modifiable cardiovascular risk factors (SMuRF-less) experience worse in-hospital outcomes than those with standard modifiable cardiovascular risk factors (SMuRFs); however, the role of a critical pathological mechanism coronary microvascular dysfunction (CMVD) in this context remains unclear.
ObjectivesTo investigate whether CMVD mediates the association between SMuRF-less status and in-hospital major adverse cardiovascular events (MACE).
MethodsA total of 1,027 STEMI patients undergoing percutaneous coronary intervention (PCI) were enrolled and classified into a SMuRFs group (≥1 SMuRF, n = 806) and a SMuRF-less group (no SMuRFs, n = 221). In-hospital MACE and post-procedural coronary angiography–derived index of microcirculatory resistance (caIMR) were compared between groups. Mediation analysis was performed to assess the mediating effect of post-procedural caIMR on the association between SMuRF-less status and in-hospital outcomes.
ResultsThe incidence of in-hospital MACE was significantly higher in the SMuRF-less group than in the SMuRFs group (15.3% vs. 7.0%, P < 0.001). After adjustment for potential confounders, mediation analysis demonstrated that post-procedural caIMR partially mediated the association between SMuRF-less status and increased in-hospital MACE risk (β = 0.284, 95% bootstrap CI: 0.101–0.498).
ConclusionElevated post-procedural caIMR, as a quantitative surrogate of CMVD, independently predicted in-hospital MACE and partially mediated the association between SMuRF-less status and adverse in-hospital outcomes in STEMI patients.