Decreased kidney function: an unrecognized and often untreated risk factor for secondary cardiovascular events after carotid surgery.

BACKGROUND AND
PURPOSE: Chronic kidney disease is an important risk factor for development and progression of atherosclerosis. The objective of the current study was to investigate the contribution of moderate kidney failure to cardiovascular (CV) mortality and morbidity after carotid endarterectomy (CEA). In addition, we investigated which proportion received optimal medical treatment or underwent diagnostic workup of the kidneys prior to CEA.
METHODS: Between 2002 and 2009, 1085 patients undergoing CEA were included in this study. Estimated glomerular filtration rate (eGFR) was assessed at baseline. Moderate kidney failure was defined as an eGFR 30-59 and compared with normal or mildly reduced kidney function (eGFR ≥60). Primary endpoint was CV death, composed of fatal myocardial infarction, fatal stroke, and ruptured abdominal aneurysm. Secondary endpoints were CV morbidity.
RESULTS: Moderate kidney failure (eGFR 30-59) was observed in 26.5% (288/1085) of the patients. During a median follow-up of 2.95 years (0.0 to 3.0 years), the adjusted hazard ratio for CV death with an eGFR 30-59 was 2.22 (1.27 to 3.89). Adjusted hazard ratio for MI with an eGFR 30-59 was 1.90 (1.04 to 3.47). No higher risk for stroke and peripheral interventions was observed. Of all patients with an eGFR 30-59, 38.3% (105/274) received angiotensin-converting enzyme inhibitors, 74.5% (204/274) received statins, and 34.4% (99/288) visited a nephrologist.
CONCLUSIONS: Patients with an eGFR 30-59 have a 2.2-fold increased risk for CV death and 1.9-fold increased risk for myocardial infarction the 3 three years after CEA compared with patients with an eGFR ≥60, independent of other CV risk factors. A minority of these patients receive optimal medical treatment, which might explain the increased risk for progression of chronic kidney disease and CV morbidity and mortality.