Differential Longitudinal Outcomes Following Percutaneous Coronary Intervention to the Left Internal Mammary Artery and Other Bypass Grafts of the LAD: Findings From the NCDR.

Objectives: Limited studies of percutaneous coronary intervention (PCI) of the left internal mammary artery (LIMA) graft exist. We compared outcomes of different bypass grafts to the left anterior descending (LAD) coronary artery.
Methods: Participants ≥65 years old in the CathPCI Registry who underwent PCI of a bypass graft to the LAD between 2009 and 2014 were included. Individuals were divided by graft type: LIMA; saphenous vein graft (SVG); or other. Clinical characteristics and outcomes using Medicare claims data for mortality, rehospitalization for myocardial infarction (MI), stroke, or unplanned repeat revascularization at 1 year were examined.
Results: There were 10,051 PCIs performed on grafts to the LAD: 6797 SVGs (67.6%), 3011 LIMA grafts (30.0%); and 243 other (2.4%). Procedural success rates (SVG 92.9%, LIMA 91.1%, other 93.4%; P=.65) and in-patient mortality rates (SVG 3.0%, LIMA 2.7%, other 2.1%; P=.61) were similar. However, dissection rates were higher in LIMA interventions (SVG 0.7%, LIMA 2.8%, other 2.5%; P<.001). At 1 year, mortality, MI, and repeat revascularization were lower in arterial grafts (mortality: SVG 16.6%, LIMA 14.8%, other 11.8% [P<.001]; MI: SVG 9.9%, LIMA, 6.6%, other 8.1% [P<.001]; revascularization: SVG 14.4%, LIMA 9.5%, other 10.4% [P<.001]). After multivariable adjustment, LIMA patients had lower rates of MI (hazard ratio, 0.71; 95% confidence interval, 0.60-0.84) and repeat revascularization (hazard ratio, 0.68; 95% confidence interval, 0.59-0.79) compared with the SVG group. Mortality was not significantly different.
Conclusions: Despite similar procedural success rates compared with SVG and other graft types, LIMA interventions were independently associated with lower rates of recurrent MI and repeat revascularization at 1 year.