The relationship between renal function and outcome from heart valve surgery.
BACKGROUND
The prognostic importance of renal function in patients undergoing surgery for valvular heart disease is poorly defined. The current study addresses this issue.


METHODS
Baseline demographic and clinical variables, including the European system for cardiac operative risk evaluation (EuroSCORE), were recorded prospectively from 514 consecutive patients undergoing heart valve surgery between April 2000 and March 2004. Patients with active infective endocarditis and/or requiring emergency surgery were excluded. The glomerular filtration rate was estimated (eGFR) using the Modification of Diet in Renal Disease equation. The primary outcome was all-cause mortality.


RESULTS
During a median follow-up of 2 years, 87 patients died. In univariable analysis, both eGFR (hazard ratio [HR] 0.69 per 10 mL/min per 1.73 m2, P<.001) and creatinine (HR 1.04 per 10 micromol/L, P<.001) predicted mortality. Estimated GFR was a stronger predictor and was used in subsequent multivariable models. It remained a powerful independent predictor of death in a multivariable model including all study variables (HR 0.70 per 10 mL/min per 1.73 m2 increase, P<.001) and in a model including EuroSCORE (HR 0.64 per 10 mL/min per 1.73 m2 increase, P<.001). After correction for preoperative EuroSCORE, an eGFR of <60 mL/min per 1.73 m2 was associated with an excess hazard of death of 2.31 (P=.001).


CONCLUSIONS
Renal function, particularly the eGFR, is a powerful predictor of outcome in patients undergoing heart valve surgery. This prognostic utility is independent of other recognized risk factors and the EuroSCORE.
Gibson
Patrick H
PH
Department of Cardiology, University of Aberdeen and Aberdeen Royal Infirmary, Aberdeen, UK.
Croal
Bernard L
BL
Cuthbertson
Brian H
BH
Chiwara
Mildred
M
Scott
Anne E
AE
Buchan
Keith G
KG
El-Shafei
Hussein
H
Gibson
George
G
Jeffrey
Robert R
RR
Hillis
Graham S
GS
D000368:Aged; D005260:Female; D005919:Glomerular Filtration Rate; D006349:Heart Valve Diseases / Q000401:mortality* / Q000601:surgery*; D006801:Humans; D007668:Kidney / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis