OBJECTIVES: To examine if preoperative microalbuminuria (MA) is associated with in increased risk of adverse outcomes in patients undergoing elective cardiothoracic surgery, and if adding information on MA could improve the accuracy of the additive EuroSCORE.

METHODS: In a follow-up study we included 962 patients undergoing elective cardiothoracic surgery from 1 April 2005 to 30 September 2007 at our department. MA (urine albumin/creatinine ratio between 2.5-25 mg/mmol) was assessed in a morning spot-urine sample. We used population-based medical registries for 30-day follow-up and compared the length of stay and adverse outcomes including (i) all-cause death, myocardial infarction, stroke, or atrial fibrillation, (ii) surgical reintervention, renal insufficiency, sternal wound infection, or septicaemia among patients with and without MA.

RESULTS: MA was found in 180 (18.7%) patients. The risk of both combined outcomes (adjusted odds ratios (ORs): 1.00 (95% confidence interval (CI): 0.77-1.30) and 1.18 (95% CI: 0.79-1.75), respectively) and most individual outcomes did not differ between the micro- and normoalbuminuric patients. The patients with MA and an additive EuroSCORE of 5 had a significantly prolonged median length of intensive care unit (ICU) stay (0.15 days [95% CI: 0.04-0.26]) and total hospital stay (0.5 days [95% CI: 0.04-0.96]). Patients with MA had a higher risk of postoperative septicaemia (OR: 12.1 [95% CI: 3.2-45.9]). Area under receiver operating characteristics curves of the EuroSCORE with regard to 30-day mortality was 0.86 both with and without MA.

CONCLUSIONS: Preoperative MA in patients undergoing elective cardiothoracic surgery was not associated with most early adverse outcomes. However, risk of septicaemia was higher and patients with MA also had a marginally longer length of ICU and hospital stay. Information on preoperative MA did not improve the accuracy of the additive EuroSCORE.