Objective — To compare the long-term outcomes of MAR versus SAR in patients with renal insufficiency.
Summary of Background Data — Previous studies have been insufficiently powered to address whether MAR confers long-term benefit over SAR in patients with renal dysfunction who require CABG.
Methods — We conducted retrospective cohort study in Ontario, Canada of patients who underwent isolated CABG (n = 23,406). The primary outcome was MACE, defined as the composite of stroke, myocardial infarction, and repeat revascularization. We compared patients by matching them on the propensity to have received SAR versus MAR, within groups with preoperative glomerular filtration rate (GFR) ≥60 mL/min/1.73 m; GFR between 30 and 60; and GFR <30.
Results — In patients with GFR ≥60, the use of MAR versus SAR was associated with a lower rate of MACE [hazard ratio (HR) 0.87 (0.80-0.94)], and a lower rate of long-term mortality [HR 0.87 (0.79-0.97)]. In those with GFR between 30 and 60, MAR was not associated with a difference in MACE [HR 1.04 (0.87-1.26)], and a lower rate of long-term mortality [HR 0.75 (0.65-0.87)] was observed. In those with GFR <30, MAR was not associated with a difference in outcomes.
Conclusions — MAR versus SAR does not correlate with a difference in MACE amongst patients with GFR between 30 and 60 and better survival raises the possibility of indication bias. Furthermore, MAR did not confer a benefit in those with severely reduced renal function. These data suggest that the potential long-term benefits of using MAR in CABG patients with renal insufficiency may be offset by competing health risks.