Impact of severity of renal dysfunction on determinants of in-hospital mortality among patients undergoing percutaneous coronary intervention

Background: Chronic kidney disease (CKD) is a known prognostic indicator of poor outcomes following percutaneous coronary intervention (PCI) for coronary artery disease. However, it is unclear whether other predictors of mortality differ among patients with varying degrees of renal impairment. Thus, we aimed to identify determinants of in-hospital mortality which are specific to patients with preserved renal function, moderate CKD, or end stage renal disease (ESRD) on dialysis, undergoing PCI. Methods: The study population included 25,018 patients who underwent PCI between January 1, 2004, and December 31, 2007, at four New York State hospitals. The primary endpoint of the study was in-hospital mortality. Results: A total of 474 (1.9%) patients had ESRD on dialysis, 6,596 (26.4%) had moderate CKD (GFR<60 ml/min/1.73m²), and 17,948 (71.7%) had preserved renal function (GFR>60 ml/min/1.73m²). Patients with ESRD and moderate CKD were older, more often male, and had higher rates of prior coronary revascularization, peripheral vascular disease, congestive heart failure, prior stroke, and diabetes than those with preserved function. All-cause in-hospital mortality rates were significantly higher in patients with ESRD and moderate CKD compared to patients with GFR >60ml/min/1.73m² (2.1% and 1.3%, respectively vs. 0.3%, p < 0.001). In multivariable analysis, ESRD (OR: 3.68, 95% CI 1.62-8.36) and moderate CKD (OR: 2.92, 95% CI 1.91-4.46) were independently associated with higher rates of in-hospital mortality. Independent predictors of mortality were markedly distinct in each group and included female gender and myocardial infarction within the past 72 hr in the ESRD group, versus left ventricular ejection fraction, peripheral vascular disease, congestive heart failure, emergency PCI, and absence of prior PCI in the moderate CKD group and age, prior bypass graft surgery, congestive heart failure, emergency PCI, and absence of prior myocardial infarction in patients with preserved renal function Conclusions: Patients with moderate CKD or ESRD undergoing PCI have an approximately threefold increase in the risk of in-hospital mortality compared with patients with preserved renal function, with radically different mortality predictors existing for varying levels of renal function.