Tae Oh Kim MD^a, Do-Yoon Kang MD^a, Jung-Min Ahn MD^a, Seon Ok Kim MSc^b, Pil Hyung Lee MD^a, Junghoon Lee MD^a, Ju Hyeon Kim MD^a, Ho Jin Kim MD^c, Joon Bum Kim MD^c, Suk Jung Choo MD^c, Cheol-Hyun Chung MD^c, Jae-Won Lee MD^c, Seung-Jung Park MD^a, Duk-Woo Park MD^a,* on behalf of the Asan Medical Center–Multivessel Revascularization Registry Investigators

^aDivision of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
^bDivision of Biostatistics, Center for Medical Research and Information, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
^cDivision of Cardiac Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea

^*Corresponding author.

Background
The long-term prognostic impact of mildly decreased renal function in patients undergoing coronary revascularization is still unknown.

Objectives
The goal of this study was to investigate the long-term prognostic impact of mildly decreased renal function and comparative outcomes after percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) in such a risk group of patients.

Methods
From the Asan Medical Center–Multivessel Revascularization registry, 10,354 eligible patients who underwent coronary revascularization were classified into 3 groups (stage I [n = 3,735]: normal renal function; stage II [n = 5,122]: mild dysfunction; and stage III [n = 1,497]: moderate dysfunction) according to estimated glomerular filtration rate. The primary outcome was the composite of death, spontaneous myocardial infarction, or stroke. Propensity score matching was used to assemble a cohort of patients with similar baseline characteristics.

Results
After propensity matching, the risk for primary composite outcome was not different between the stage I and the stage II group (HR: 1.12; 95% CI: 0.97-1.30). However, the risk of the primary outcome was significantly higher in the stage III group than in the stage I group (HR: 1.50; 95% CI: 1.22-1.84). The relative effect of PCI vs CABG for the primary outcome was similar in the matched cohort of each renal function group of stages I, II, and III.

Conclusions
In patients with multivessel disease after revascularization by PCI or CABG, the presence of mildly decreased renal function was not significantly associated with an increased risk of the primary composite outcome and mortality. Comparative outcomes after PCI and CABG were similar in the borderline-risk group. (Asan Medical Center–Multivessel Revascularization registry; NCT02039752)