Frequency, Risk Factors, and Outcome of Definite Stent Thrombosis: A Single-Center Experience

Introduction Stent thrombosis (ST) is a serious and potentially life-threatening complication of primary or complex high-risk percutaneous coronary intervention (PCI). Multiple factors are said to precipitate ST, related to the patient's clinical comorbidities, lesion characteristics, operative technique, and post-procedural care. The older-generation stents were thought to be involved in early ST. Though the new generation of drug-eluting stents decreases the incidence of early and late ST, patients are still at risk of very late stent thrombosis (VLST). Objective To evaluate the frequency, risk factors, and outcomes of definite ST in developing and resource-constrained countries like Pakistan, where PCIs, including primary PCI, complex PCI, and PCI in high-risk populations, are performed routinely. Methods This observational cross-sectional study included all patients who underwent primary and complex high PCI between 2012 and 2017 at TABBA Heart Institute (THI), Karachi, Pakistan. Results We included a total of 6587 patients in our study, and among the enrolled sample size, 22 (0.33%) had definite ST. Acute stent thrombosis (AST) was found in seven patients, sub-acute stent thrombosis (SAST) in 10, late stent thrombosis (LST) in two, and VLST were observed in three patients. The basic characteristics of our study ST population were as follows: mean age was 58 years, 95.5% were male, 4.5% were female, nine patients (40%) had diabetes mellitus, 15 patients (68%) had hypertension, 11 (50%) had dyslipidemia, and four patients were smokers (18%). Conclusion The frequency, risk factors, and rate of mortality of definite ST in the Pakistani population who underwent primary and complex high-risk PCI reflect nearly equal statistics observed in other studies. As seen in other international studies, the incidence rate of VLST was higher in our population.