Postoperative renal dysfunction and preoperative left ventricular dysfunction predispose patients to increased long-term mortality after coronary artery bypass graft surgery.
BACKGROUND
Both preoperative left ventricular dysfunction and postoperative renal function deterioration are associated with increased long-term mortality after cardiac surgery. The influence of preoperative left ventricular dysfunction on postoperative renal dysfunction and long-term mortality is not defined.


METHODS
We collected data from 641 consecutive patients undergoing coronary bypass surgery with cardiopulmonary bypass in 1991 at our institution. Prospective follow-up was through to July 2004.


RESULTS
In-hospital mortality was 2.7% (17 of 641). During follow-up, 248 (40%) patients discharged alive died (5 and 10 yr survival 90% and 70%, respectively). On univariate analysis, preoperative left ventricular dysfunction (ejection fraction <50%) and an increase in serum creatinine > or =25% in the first postoperative week were associated with long-term mortality. The associated mortality risk was additive in predominantly non-overlapping patients groups: the hazard ratio (HR) for renal function deterioration only was 1.41 [95% confidence interval (CI) 0.95-2.32, P=0.083; n=64] and for left ventricular dysfunction only 1.71 (95% CI 1.26-2.95, P=0.0026; n=73). In patients in whom both were present, HR was 3.23 (95% CI 2.52-20.28, P<0.0001; n=20). Although postoperative renal dysfunction was associated with left ventricular dysfunction (P=0.008), both left ventricular dysfunction and postoperative renal function deterioration were independently associated with long-term mortality on multivariate analysis, as were age and the use of venous conduits.


CONCLUSIONS
Both postoperative renal function deterioration and preoperative left ventricular dysfunction independently identify largely non-overlapping groups of patients with increased long-term mortality after coronary bypass surgery. In the group of patients with both factors present, the mortality risks appear additive.
Department of Cardiothoracic Surgery, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, Groningen 9713 GZ, The Netherlands. b.loef@hccnet.nl
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Stegeman
D058186:Acute Kidney Injury / Q000209:etiology* / Q000628:therapy; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000401:mortality; D003404:Creatinine / Q000097:blood; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods; D011379:Prognosis; D017582:Renal Replacement Therapy; D018487:Ventricular Dysfunction, Left / Q000150:complications* / Q000401:mortality
D015415:Biomarkers; D003404:Creatinine