A Bayesian Risk Index for Predicting Risk of Major Adverse Cardiac Events at 12 Months Post Angioplasty and Its Application to Clinical Service Quality Improvement

Abstract

Background: Stent thrombosis (ST) is a feared complication of percutaneous coronary intervention due to its adverse consequences.Methods: We analysed records of 4226 consecutive patients from January 2004 to October 2010 who underwent successful stenting. Baseline clinical characteristics, angiographic features and outcomes were compared in patients with and without ST.Results: A total of 64 cases of angiographic ST were recorded including six patients who had more than one episode of ST. Fifty-six percent of ST cases occurred in the first 30 days, 31% in days 30-365 and 13% after 365 days. Patients undergoing primary PCI (PPCI) had the highest risk of ST (3.1% vs 1.1% in all others, p = 0.0001). There was no difference in ST rate between patients treated with DES and BMS (1.4% vs 1.6%, p = ns). Incidence of ST beyond one year was 0.2% for BMS and 0.3% for DES (p = ns). There was a trend towards higher ST rate in patients who had a 2.25 mm diameter stent compared to larger stents (3.8% vs 1.5%, p = 0.06). Age, sex, diabetes and smoking status were not predictive of ST. Early experience with 20 primary PCI patients treated with Prasugrel was associated with no stent thrombosis. Patients with ST had a mortality rate of 10.9% compared with 2.7% in those without ST (p < 0.01).Conclusions: The risk of ST is higher in the first 30 days post procedure. PPCI patients had the highest risk of ST. There was no significant difference in ST rate between DES and BMS. ST was associated with significantly higher mortality during follow-up.