Background: Prolonged dual antiplatelet therapy (DAPT) after coronary stenting might reduce incidence of stent thrombosis at the expense of higher bleeding risk. There was conflicting evidence for effect of prolonged DAPT on survival. The aim of this retrospective study was to examine the effect of prolonged DAPT on survival in left main disease treated with drug eluting stent (DES).
Methods: From January 2007 to December 2010, 550 consecutive patients who underwent left main stenting in 8 public hospitals of Hong Kong were recruited for retrospective analysis. Clinical follow up data were collected up till 30 June 2014. Subgroup (389 patients) analysis was performed in DES patients who survived the first year without major adverse cardiac event (MACE).
Results: The mean age was 68±11 years with male predominance (74%). Diabetes mellitus, hypertension, hypercholesterolemia and smoking history was present in 158 (41%), 247 (64%), 296 (76%) and 161 (41%) patients respectively. Prior myocardial infarction (MI), prior stroke, peripheral vascular disease and creatinine >200 mmol/L (CRI) was found in 136 (35%), 36 (9%), 6 (1.5%), and 12 (3%) patients respectively. Intravascular ultrasonography was performed in 307 (79%) patients. High pressure post-dilatation was performed in 338 (87%) patients. One hundred ninety-two (49%) patients received prolonged DAPT beyond one year. By cox proportional hazard function analysis, old age, prior stroke, CRI were independent predictors of medium term (262±74 weeks) all-causes death. The hazard ratio for prolonged DAPT group was 1.08 (95% confidence interval 0.55–2.10). Stent thrombosis, nonfatal MI and major bleeding rate beyond the first year after implantation of DES was 0.3%, 1% and 0.6% per year respectively for patients receiving just one year DAPT while the corresponding figure was 0.5%, 0.7% and 0.9% per year for patients receiving prolonged DAPT.
Conclusion: For patients without MACE at one year after implantation of DES in left main artery, prolonging DAPT did not affect medium term survival.