The influence of coronary microvascular obstruction (no-reflow) syndrome during percutaneous coronary interventions on myocardial infarction outcomes in current clinical practice

Background. Coronary microvascular obstruction (CMVO, no-reflow) syndrome develops in 5–20% of patients with myocardial infarction (MI) during percutaneous coronary intervention (PCI). The negative impact of CMVO on prognosis was known long ago. However, clinical practice in MI treatment has changed significantly. The introduction of new approaches to the prevention and treatment of CMVO requires a reassessment of its prognostic role using modern statistical methods. Furthermore, aspects such as the causes of death in patients with CMVO and the impact of this complication on radiation exposure also remain understudied.

Aim: To compare in-hospital and long-term outcomes in patient groups with MI and PCI, complicated or uncomplicated by CMVO in current clinical practice.

Material and Methods. A single-center cohort study was conducted on patients with MI and PCI, complicated or not complicated by the development of CMVO. The CMVO criteria were a TIMI flow grade of < 3 or a Myocardial blush grade of < 2. To assess patient radiation exposure during PCI, the dose area product (DAP) was analyzed. Propensity score matching was used to adjust for intergroup differences. Multivariate analysis of the risk of long-term mortality was performed using Cox regression, accounting for time-dependent effects. Kaplan – Meier curves were plotted, and the Log-rank test was used to compare survival.

Results. A total of 1264 patients were enrolled. After matching, 418 patients remained: 209 patients without CMVO and 209 with non-CMVO. In the CMVO group, the DAP was 59.9 [39.8; 94.5] Gycm², compared to 82.8 [59.2; 135.5] Gycm² in the CMVO group (p < 0.001). At the in-hospital stage, 9 (4.3%) and 22 (11.0%) patients died, respectively (p = 0.015). Long-term outcomes were tracked in 46% of patients (median follow-up 498 [294; 1001] days). In the long-term period, death was recorded in 15 (7.2%) patients in the group without CMVO and in 37 (18%) in the group with CMVO (p = 0.001). Multivariate analysis of the risk of long-term mortality was performed using Cox regression, accounting for time-dependent effects. Kaplan – Meier curves were plotted, and the Log-rank test was used to compare survival. Among the causes of long-term death, decompensation of chronic heart failure was more frequent in the CMVO group compared to the successful reperfusion group (41% vs. 0%, respectively, p = 0.002).

Conclusion. The development of CMVO during PCI in patients with MI is associated with an extremely high risk of death in the early postoperative period and leading to worse long-term survival overall. The occurrence and perioperative treatment of CMD lead to greater radiation exposure for the patient. Decompensation of chronic heart failure is the leading cause of long-term death in patients with CMD.

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