[The impact of myocardial infarct size dynamics on left ventricular remodeling in STEMI patients after primary percutaneous coronary intervention].

Objective: To explore the impact of changes of myocardial infarct size on left ventricular adverse remodeling in patients with acute ST-segment elevation myocardial infarction (STEMI) after primary percutaneous coronary intervention (PCI). Methods: This was a prospective cohort study. The STEMI patients who underwent primary PCI in the First Medical Center of the Chinese People's Liberation Army General Hospital, Beijing Anzhen Hospital, Hainan Hospital of the Chinese People's Liberation Army General Hospital and Guangxi Yulin First People Hospital from January 1, 2017 to January 1, 2022 were enrolled. Cardiac magnetic resonance (CMR) was performed to dynamically assess the myocardial infarct size and calculate the rate of infarct size change between the acute phase (5 to 7 days post-primary PCI) and 6-month follow-up. The endpoint was left ventricular adverse remodeling which was defined as an increase of more than 20% in left ventricular end-diastolic volume (LVEDV) assessed by CMR at 6 months after primary PCI compared with LVEDV at 1 week after primary PCI. Based on serial CMR assessments, the patients were divided into left ventricular adverse remodeling group and non-remodeling group. The receiver operating characteristic (ROC) curve was used to evaluate the predictive performance of infarct size change for left ventricular adverse remodeling, and according to the optimal cutoff value, improved infarct size was defined as a decrease of >20% in the infarct size measured by CMR at 6 months after primary PCI compared with infarct size at 1 week after primary PCI. Multivariate logistic regression analysis was performed to identify the protective factors and risk factors for left ventricular adverse remodeling. Results: A total of 267 patients were enrolled, aged (58±11) years, with 234 males (87.6%). And 73 cases in the left ventricular remodeling group and 194 cases in the non-remodeling group. Infarct size assessed by CMR at 6 months after primary PCI decreased significantly compared with infarct size at 1 week after primary PCI in the left ventricular remodeling group ((23±13)% vs. (27±12)%, P=0.004), the same as in the non-remodeling group ((18±10)% vs. (23±10)%, P<0.001). The area under the ROC curve for the rate of infarct size change in predicting left ventricular remodeling was 0.735 (95%CI 0.670-0.799, P<0.001), a 20% reduction was the optimal cut-off value. Compared to the patients with non-improved infarct size, the incidence of left ventricular adverse remodeling was significantly lower in the patients with improved infarct size (18% (24/133) vs. 37% (49/134), P=0.001). Multivariate logistic regression analysis showed that improvement in IS was a protective factor for left ventricular adverse remodeling (OR=0.376, 95%CI 0.236-0.721, P=0.002). Conclusion: Patients with STEMI who experience obvious reduction in infarct size after primary PCI have a significantly reduced risk of left ventricular adverse remodeling.