Methods and results: The current study analyzed 4894 patients with unprotected LMCAD enrolled in the multicenter IRIS-MAIN registry. Renal insufficiency was graded according to the baseline renal function (eGFR). The primary clinical outcome was major adverse cardiocerebrovascular event (MACCE), defined as a composite of death, myocardial infarction, stroke, and any revascularization. At baseline, 3824 (78%) had preserved renal function (eGFR =60 ml·min -1·1.73m-2), 838 (17%) had moderate renal dysfunction (eGFR of = 30 and <60), and 232 (5%) had severe renal dysfunction (eGFR <30). At 2 years, the rates of MACCE were significantly higher in patients with lower levels of eGRF (9.1% in eGRF =60, 16.0% in eGFR of = 30 and <60, and 36.2% in eGRF <30, respectively, P<0.001). After multivariable adjustment, as compared with patients with eGFR = 60, the hazard ratios (HR) for MACCE proportionally increased for patients with eGFR of = 30 and <60 (HR 1.46, 95% CI 1.18-1.79) and for those with eGFR <30 (HR 3.39, 95% CI 2.61-4.40). The adjusted risks for MACCE was similar between percutaneous coronary intervention (PCI) and coronary-artery bypass grafting (CABG) in patients with preserved and moderate renal dysfunction. However, in patients with severe renal dysfunction, PCI was associated with a significantly higher risk of MACCE compared to CABG (38.5% vs. 24.7%, HR 1.80, 95% CI 1.03-3.13, P=0.04).
Conclusions: The degree of renal insufficiency was proportionately associated with worse clinical outcomes in patients with LMCAD. In patients with severe renal dysfunction of eGFR of <30, PCI was associated with a higher risk of MACCE as compared with CABG.