Multivariable prediction of in-hospital mortality associated with aortic and mitral valve surgery in Northern New England.
BACKGROUND
Predicting risk for aortic and mitral valve surgery is important both for informed consent of patients and objective review of surgical outcomes. Development of reliable prediction rules requires large data sets with appropriate risk factors that are available before surgery.


METHODS
Data from eight Northern New England Medical Centers in the period January 1991 through December 2001 were analyzed on 8943 heart valve surgery patients aged 30 years and older. There were 5793 cases of aortic valve replacement and 3150 cases of mitral valve surgery (repair or replacement). Logistic regression was used to examine the relationship between risk factors and in-hospital mortality.


RESULTS
In the multivariable analysis, 11 variables in the aortic model (older age, lower body surface area, prior cardiac operation, elevated creatinine, prior stroke, New York Heart Association [NYHA] class IV, congestive heart failure [CHF], atrial fibrillation, acuity, year of surgery, and concomitant coronary artery bypass grafting) and 10 variables in the mitral model (female sex, older age, diabetes, coronary artery disease, prior cerebrovascular accident, elevated creatinine, NYHA class IV, CHF, acuity, and valve replacement) remained independent predictors of the outcome. The mathematical models were highly significant predictors of the outcome, in-hospital mortality, and the results are in general agreement with those of others. The area under the receiver operating characteristic curve for the aortic model was 0.75 (95% confidence interval [CI], 0.72 to 0.77), and for the mitral model, 0.79 (95% CI, 0.76 to 0.81). The goodness-of-fit statistic for the aortic model was chi(2) [8 df] = 11.88, p = 0.157, and for the mitral model it was chi(2) [8 df] = 5.45, p = 0.708.


CONCLUSIONS
We present results and methods for use in day-to-day practice to calculate patient-specific in-hospital mortality after aortic and mitral valve surgery, by the logistic equation for each model or a simple scoring system with a look-up table for mortality rate.
Nowicki
Edward R
ER
Dartmouth Medical School, Hanover, New Hampshire 03756, USA.
Birkmeyer
Nancy J O
NJ
Weintraub
Ronald W
RW
Leavitt
Bruce J
BJ
Sanders
John H
JH
Dacey
Lawrence J
LJ
Clough
Robert A
RA
Quinn
Reed D
RD
Charlesworth
David C
DC
Sisto
Donato A
DA
Uhlig
Paul N
PN
Olmstead
Elaine M
EM
O'Connor
Gerald T
GT
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001021:Aortic Valve / Q000601:surgery*; D019540:Area Under Curve; D006348:Cardiac Surgical Procedures / Q000401:mortality*; D001026:Coronary Artery Bypass; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000401:mortality; D017052:Hospital Mortality; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery*; D015233:Models, Statistical; D015999:Multivariate Analysis; D009511:New England / Q000453:epidemiology; D012372:ROC Curve; D012307:Risk Factors