Impact of renal failure on in-hospital outcomes after coronary artery bypass surgery.

BACKGROUND

Chronic kidney disease (CKD) is a predictor of increased mortality in patients undergoing coronary artery bypass surgery (CABG).

OBJECTIVE

To evaluate the characteristics and predictors of increased mortality in the CKD population submitted to CABG. To compare in-hospital outcomes between patients with and without CKD, and with and without development of acute renal failure (ARF).

METHODS

Retrospective analysis of a prospective database of all isolated CABG performed in a single public tertiary hospital from 1999 to 2007. CKD was considered when creatinine > 1.5 mg/dl. Clinical characteristics, mortality and post-operative complications were evaluated according to renal function.

RESULTS

Of 3,890 patients, 362 (9.3%) had CKD. This population was older, presented grater prevalence of hypertension, left ventricular dysfunction, previous stroke, peripheral vascular disease and three-vessel disease. In-hospital outcomes revealed greater incidence of stroke (5.5% vs 2.1%), atrial fibrillation (16 vs 8.3%), low cardiac ouput syndrome (14.4% vs 8.5%), longer stay in intensive care unit (4.04 vs 2.83 days), and greater mortality (10.5% vs 3.8%). Logistic regression: female gender, smoking, diabetes and peripheral vascular disease were associated with higher in-hospital mortality within the CKD group. Patients who did not develop post-operative ARF presented 3.5% mortality; non-dialytic ARF: 35.4%; dialytic ARF: 66.7% mortality. Mortality was directly related to the stage of CKD, according to glomerular filtration rate.

CONCLUSION

CKD patients submitted to CABG represent a high risk population, with increased incidence of complications and mortality. Post-operative ARF is a strong in-hospital mortality predictor. Glomerular filtration rate was inversely related to mortality.