A need for speed? Bypass time and outcomes after isolated aortic valve replacement surgery.
OBJECTIVE
To determine in the modern era if cardiopulmonary bypass (CPB) time has a significant effect on postoperative morbidity, mortality and long-term survival in patients undergoing isolated aortic valve replacement (AVR) surgery.


METHODS
Analysis of a prospectively collected cardiac surgery database was performed. Uni- and multivariate analysis on the need of resternotomy for bleeding, mediastinal blood loss, intensive care unit (ICU) length of stay, hospital length of stay, in-hospital mortality and long- term survival was performed. Only patients with a cross-clamp time <90 min were analysed to exclude technical issues confounding the results.


RESULTS
A total of 1863 isolated first-time AVR procedures were analysed, with an in-hospital mortality rate of 2.4%. The rate of long-term follow-up achieved was 100%. Univariate analysis revealed that CPB time (minutes) had no significant effect on resternotomy (P = 0.5), creatinine kinase muscle-brain isoenzyme (CKMB) release (P = 0.8) and long-term survival (P = 0.06), but was significantly associated with mediastinal blood loss (P = 0.01), ICU length of stay (P = 0.02), hospital length of stay (P = 0.03) and in-hospital mortality (P < 0.001). Multivariate analysis identified that bypass time (min) was a significant factor associated with mediastinal blood loss (P < 0.001), ICU length of stay (P = 0.01), postoperative length of stay (P < 0.001) and in-hospital mortality (odds ratio [OR] 1.02, 95% CI 1.01-1.04, P = 0.01), but not long-term survival. Multivariate analysis identified that era of surgery had no significant effect on CKMB release (P = 0.2), mediastinal blood loss (P = 0.4) and in-hospital mortality (P = 0.9), but the latter era of this study was significantly associated with a reduced postoperative length of stay (P < 0.001), reduced ICU length of stay (P < 0.001), reduced need for resternotomy for bleeding (OR 0.62, 95% CI 0.41-0.94, P = 0.02) and improved long-term survival (hazard ratio 0.76, 95% CI 0.59-0.96, P = 0.02). Adjusting for era made no difference with respect to the above study findings.


CONCLUSIONS
Despite improvements over time with regard to morbidity, mortality and long-term survival, CPB time remains a significant factor determining mediastinal blood loss, ICU and hospital length of stay, and in-hospital mortality.
Department of Cardiac Surgery, Liverpool Heart and Chest Hospital, Liverpool, UK.
John
J
Chalmers
Department of Cardiac Surgery, Liverpool Heart and Chest Hospital, Liverpool, UK.
Mark
M
Pullan
Department of Cardiac Surgery, Liverpool Heart and Chest Hospital, Liverpool, UK.
Neeraj
N
Mediratta
Department of Cardiac Surgery, Liverpool Heart and Chest Hospital, Liverpool, UK mpoullis@hotmail.com.
Michael
M
Poullis
D000368:Aged; D001021:Aortic Valve / Q000601:surgery*; D016063:Blood Loss, Surgical; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000401:mortality; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000401:mortality; D017052:Hospital Mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D061646:Operative Time; D011183:Postoperative Complications / Q000401:mortality / Q000628:therapy; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
Aortic valve replacement; Cardiopulmonary bypass; Mortality; Survival