Renal function is associated with risk of atrial fibrillation after cardiac surgery.

BACKGROUND

Atrial fibrillation (AF) frequently occurs after cardiac surgery and is responsible for increased morbidity and resource use. The aim of the present study was to evaluate the association of impaired renal function and the development of postoperative AF.

METHODS AND RESULTS

Patients undergoing elective cardiac surgery in the absence of significant left ventricular dysfunction (n=253; average age 65+/-11 years) were recruited to the present prospective study. Ninety-nine patients (39.1%) developed AF during the postoperative period. Creatinine clearance, estimated by the calculated glomerular filtration rate (GFR), was prospectively assessed to determine the association of baseline renal function and the development of postoperative AF. Baseline calculated GFR was assessed as a continuous and a categorical variable (normal: greater than 90 mL/min/1.73 m(2); mildly decreased: 60 mL/min/1.73 m(2) to 89 mL/min/1.73 m(2); and moderately to severely decreased: less than 60 mL/min/1.73 m(2)). Baseline creatinine clearance was 72+/-22.2 mL/min/1.73 m(2) and 78.8+/-23.5 mL/min/1.73 m(2) in patients with and without postoperative AF, respectively (P=0.02). There was an independent association between decreasing calculated GFR and the development of postoperative AF (OR for 10 mL decrease in calculated GFR: 1.21, 95% CI 1.02 to 1.39). In addition to calculated GFR, surgery for valvular heart disease (versus coronary artery bypass grafting [OR 2.23, 95% CI 1.09 to 3.14; P<0.01]), age (OR per 10-year increase in age 1.92, 1.18 to 2.59) and perioperative nonuse of beta-adrenergic blockers (OR 1.62, 95% CI 1.12 to 3.55; P<0.01) were identified as independent predictors of postoperative AF.

CONCLUSIONS

In the setting of cardiac surgery, impaired calculated GFR is associated with an increased risk for the development of postoperative AF. These data provide additional evidence supporting the association between renal dysfunction and adverse cardiovascular outcomes.