A preoperative index of mortality for patients undergoing surgery of type A aortic dissection.
BACKGROUND
The aim of this study was to identify and stratify the most important preoperative factors for in-hospital death after surgery for type A aortic dissection.


METHODS
From January 1985 to June 1998, 108 patients underwent surgery for type A aortic dissection. 89.9% of the patients had an acute type A dissection (AD), whereas 11.1% had a chronic dissection (CD). Cardiac tamponade and shock occurred in 22% and 14.8% of the patients, respectively. The location of the primary intimal tear was in the ascending aorta in 71.2% of the cases, in the arch in 16.6% and in the descending aorta in 7.4%. Univariate and multivariate analyses were conducted to identify non-embolic variables independently correlated to in-hospital death. A predictive model of in-hospital mortality was then constructed by means of a mathematical method with the variables selected from logistic regression analysis.


RESULTS
The overall in-hospital mortality rate was 20.3% (22/108 patients), being 9% for CD and 21.6% for AD. Emergent procedures had an in-hospital mortality rate of 47.6%, whereas non-emergent operations had an in-hospital mortality rate of 13.7% (p<0.01). Univariate analysis revealed among 39 preoperative and operative variables, age (years), age >70 years, remote myocardial infarction, cerebrovascular dysfunction, diabetes, preoperative renal failure, shock, cardiopulmonary bypass time (minutes), emergency operation as factors associated to in-hospital death (p<0.05). Stepwise logistic regression analysis selected as independent predicting variables (p<0.05), remote myocardial infarction (p=0.006), preoperative renal failure (p=0.032), shock (p=0.001), age >70 years (p=0.007). Finally, a probability table of death risk was obtained with the logistic regression coefficients. The lower death probability (10.6%) was calculated in absence of risk variables; the higher one in presence of all of them (79.7%). Between these extremes, a total of 64 combinations of death risk were obtained.


CONCLUSIONS
Increasing age, shock, coronary artery disease and renal failure are variously associated to a high risk of in-hospital death after surgical correction of type A aortic dissection. This predictive model of death probability allows to collocate preoperatively patients with type A aortic dissection at different levels of risk for in-hospital death.
Spirito
R
R
Department of Cardiovascular Surgery, Cardiological Center I Monzino Foundation, IRCCS, University of Milan, Via Parea 4, 20138 Milan, Italy.
Pompilio
G
G
Alamanni
F
F
Agrifoglio
M
M
Dainese
L
L
Parolari
A
A
Reali
M
M
Grillo
F
F
Fusari
M
M
Biglioli
P
P
D000208:Acute Disease; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000784:Aortic Dissection / Q000401:mortality* / Q000601:surgery; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality* / Q000601:surgery; D017545:Aortic Aneurysm, Thoracic / Q000401:mortality* / Q000601:surgery; D002305:Cardiac Tamponade / Q000209:etiology; D002908:Chronic Disease; D004630:Emergencies; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D011336:Probability; D012044:Regression Analysis; D051437:Renal Insufficiency / Q000401:mortality; D012770:Shock, Cardiogenic / Q000209:etiology