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Publication Date

11-20-2015

Keywords

stent thrombosis, percutaneous coronary intervention, coronary artery bypass grafting, left anterior descending artery

Abstract

Background: Stent thrombosis is an infrequent but catastrophic complication of percutaneous coronary intervention (PCI). Many studies usually involve few stent thrombosis patients, generally less than 60, given its prevalence. While dual antiplatelet therapy has decreased stent thrombosis significantly in the general population, there are still patients who present with occurrence and recurrence of stent thrombosis.

Purpose: We sought to define the prevalence of site-specific stent thrombosis in a larger cohort of patients by specific coronary territories and determine if this had an effect on cardiovascular outcomes. In addition we sought to elucidate the role of previous coronary artery bypass grafting (CABG) and subsequent PCI to determine if there is increased risk of stent thrombosis in specific post-CABG coronary artery territories and if these altered overall cardiovascular outcomes.

Methods: A retrospective review of our database on all patients presenting with stent thrombosis over the last 5 years was performed. Patients were included based on the accepted Academic Research Consortium definition of stent thrombosis.

Results: From January 2009 to February 2014, 220 patients were found to have had a stent thrombosis. Of these, 110 (50.0%) had left anterior descending (LAD) artery lesions, 82 (37.3%) had right coronary artery (RCA) lesions and 26 (11.8%) had a stent thrombosis in the left circumflex artery (LCx). Prevalences of traditional risk factors were essentially equivalent regardless of which coronary artery developed stent thrombosis. All patients were on dual antiplatelet prior to developing stent thrombosis. Further analysis revealed 38 (17.3%) had a prior history of CABG. A significant difference among the location of stent thrombosis and the history of CABG (P = 0.043) was seen; 30.8% (n = 8) of patients with LCx stent thrombosis had prior CABG compared to 10.9% (n = 12) and 22% (n = 18) with LAD and RCA stent thrombosis, respectively.

Conclusion: In a large cohort of patients with stent thrombosis, LAD and RCA lesions were predominant, with LAD lesions representing half of all stent thromboses. PCI of these coronary territories thus infers a higher risk of stent thrombosis even in the presence of optimal medical therapy. Once stent thrombosis occurs, no significant difference in outcomes is seen based on location of the lesion alone. Additionally, patients who had prior CABG were significantly more likely to have stent thrombosis in the LCx and less likely in the LAD. This could be due to the fact that the left internal mammary artery graft is more often patent than vein grafts, which are more often anastomosed to the LCx and RCA and are at higher risk of needing stent placement after CABG.

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