[Long-term clinical outcomes after percutaneous coronary intervention for ST-segment elevation myocardial infarction due to late and very late stent thrombosis].

Objective: To explore the prognosis and influencing factors of ST-segment elevation myocardial infarction (STEMI) due to late stent thrombosis (LST) and very late stent thrombosis (VLST).

Methods: Patients who underwent percutaneous coronary intervention (PCI) for STEMI caused by LST and VLST at Tianjin Chest Hospital from January 2016 to June 2021 were selected as the study subjects, and long-term follow-up was conducted. The baseline clinical features, laboratory examination indicators, echocardiography results, coronary angiography and intervention treatment characteristics, and antiplatelet treatment status of patients were collected. The study endpoint was major adverse cardiovascular event (MACE), including all-cause mortality, target vessel revascularization (TVR), myocardial infarction, and recurrent stent thrombosis (RST). Patients were divided into MACE group and non-MACE group based on the occurrence of MACE. Cox regression analysis was used to determine the univariate and multivariate predictive factors for MACE occurrence in STEMI patients caused by LST and VLST during long-term follow-up after PCI. Kaplan-Meier survival curves were plotted to analyze the cumulative survival rate without MACE during follow-up in subgroups of patients with different levels of fibrinogen (Fib) and initial number of stents. The incidence of MACE among patients receiving different drug-eluting stent (DES) treatments was compared.

Results: A total of 418 patients diagnosed STEMI caused by LST and VLST through coronary angiography were enrolled, of which 115 had MACE and 303 did not. Among them, 404 cases (96.65%) completed follow-up, with a median follow-up time of 27.25 (18.00, 37.00) months. Cox regression analysis showed that Fib [hazard ratio (HR) = 2.840, 95% confidence interval (95%CI) was 1.329-6.066, P = 0.007], non-culprit vascular stenosis > 50% (HR = 5.974, 95%CI was 1.634-21.848, P = 0.007), initial stent quantity (HR = 3.314, 95%CI was 1.677-6.552, P = 0.001), B2/C lesions (HR = 5.463, 95%CI was 1.396-21.373, P = 0.015), and cardiogenic shock (HR = 4.141, 95%CI was 1.101-15.568, P = 0.035) were independently associated with the occurrence of MACE. The Kaplan-Meier survival curve showed that the higher the Fib level, the lower the cumulative survival rate without MACE (82.8%, 70.1%, 40.5%, P < 0.01); the more initial stents, the lower the cumulative survival rate without MACE (75.0%, 57.7%, 36.5%), with patients with initial stents ≥ 3 having the lowest cumulative survival rate without MACE (P < 0.001). A total of 210 patients (50.2%) received secondary stent treatment, and there was no significant difference in the incidence of MACE between patients receiving first and second generation DES treatment (27.3% vs. 24.7%, P > 0.05), but patients receiving first generation DES had a higher proportion of all-cause mortality (22.3% vs. 10.1%, P < 0.05). Compared with patients receiving smaller diameter DES treatment (< 2.75 mm), patients receiving larger diameter DES treatment (≥2.75 mm) had a significantly lower incidence of MACE (20.5% vs. 35.9%, P < 0.05).

Conclusions: Long-term clinical outcomes after PCI for STEMI due to LST and VLST are unfavorable, with a high rate of MACE. The treatment of this particular type STEMI remains challenging, re-implantation of second generation DES or a larger diameter DES (≥2.75 mm) may be beneficial.