Left Internal Mammary Artery Versus Coronary Stents: Impact on Downstream Coronary Stenoses and Conduit Patency

BACKGROUND The study compared downstream coronary and conduit disease progression in the left anterior descending coronary artery treated with coronary artery bypass grafting using the left internal mammary artery (LIMA) versus percutaneous coronary intervention with bare metal stent (BMS) or drug eluting stent (DES). METHODS AND RESULTS A total of 12 301 consecutive patients underwent isolated primary coronary revascularization, of which 2386 met our inclusion criteria (Percutaneous coronary intervention, n=1450; coronary artery bypass grafting, n=936). Propensity score analysis matched 628 patients, of which 468 were treated to the left anterior descending with coronary artery bypass grafting with LIMA (n=314), percutaneous coronary intervention with BMS (n=94), and DES (n=60). Coronary angiograms were analyzed by quantitative coronary angiography (QCA; n=433). Cumulative downstream coronary and conduit disease progression were estimated by Kaplan-Meier method and effect of treatment type by Cox proportional hazard models. Patients treated with LIMA had significantly lower risk of downstream coronary disease progression at follow-up angiogram compared with BMS and DES (hazard ratio [HR] [95% CI], 0.34; [0.20-0.59]; P=0.0002; and HR [95% CI], 0.39; [0.20-0.79]; P=0.01, respectively). LIMA was associated with a lower risk of conduit disease progression compared to BMS and DES (HR [95% CI], 0.18; [0.12-0.28]; P<0.001; and HR [95% CI], 0.27; [0.16-0.46]; P<0.001, respectively). BMS was associated with higher HR for downstream coronary and conduit disease progression compared with DES, but the difference did not reach statistical significance (HR [95% CI], 1.13; [0.57-2.36]; P=0.73; and HR [95% CI], 1.46; [0.88-2.50]; P=0.14, respectively). CONCLUSIONS LIMA grafting to left anterior descending is associated with significantly lower risk of downstream coronary and conduit disease progression compared to percutaneous coronary intervention with BMS and DES.