Predictors and prognosis of PCI-related myocardial injury in chronic total occlusion

Background: Periprocedural myocardial injury (PMI) is associated with major adverse cardiovascular events (MACE) after percutaneous coronary intervention (PCI). However, its incidence and prognostic impact in chronic total occlusion (CTO) PCI remains unclear. Method: To evaluate the predictors and prognostic impact of PMI following PCI in patients with CTO. This study included 132 patients; of them, 8 in whom procedure failed were excluded. Thus, a total of 124 patients in whom procedure was successful were divided into the PMI group (n=42) and the non-PMI group (n=82) according to their c-TnI levels measured hourly after procedure. By comparing the baseline data and angiographic characteristics of the two groups, we analyzed PMI predictors and the correlation between PMI and in-hospital major adverse cardiac events. Results: : Overall, PMI occurred in 42 patients (33.9%). Comparing with non-PMI group, PMI group had more diabetes (54.8% vs 31.7%,P=0.013) and dyslipidemia (54.8% vs 13.4%, P＜0.001). Also, there were significant differences between the two groups in left ventricular ejection fraction(43.2±7.2vs47.2±8.0，P=0.027), prior myocardial infarction(54.8%vs43.1%，P=0.020), prior PCI(57.1%vs22.0%，P＜0.001) and prior CABG(14.3%vs2.4%，P=0.011). In angiographic characteristic, patients with PMI had more calcified lesions (52.4%vs24.4%，P=0.002) and were more likely to have multivessel artery disease (71.4%vs35.4%，P＜0.001). In addition, patients in the PMI group had higher J-CTO scores (3.3±1.0vs1.9±0.5，P＜0.001) and were more likely to have wire-crossing difficulties (64.3%vs37.8%，P=0.005), require the use of retrograde approach (38.1%vs7.3%，P＜0.001) and have procedural complications (19.0%vs2.4%，P=0.003). In the multivariate analysis, multivessel artery disease (odd ratio [OR]，4.347；confidence interval [CI]，1.601-11.809；P=0.004), retrograde approach (OR，4.036；CI，1.162-14.020；P=0.028) and the presence of procedural complications (a composite of iatrogenic coronary artery dissection/haematoma/perforation or cardiac tamponade)(OR，16.480；CI，2.515-107.987；P=0.003) were predictors of PMI. Conclusion: The incidence of PMI in CTO patients after PCI was about 33%. Multivessel artery disease, retrograde approach, and the presence of procedural complications were predictors of PMI after CTO-PCI. Patients who develop PMI tend to have a poorer clinical prognosis and more in-hospital MACE than those who do not develop PMI.