Compared with the open group, the laparoscopic group was younger and had lower American Society of Anesthesiologists scores, higher serum albumin levels, and lower prothrombin time and platelet count.
In unadjusted analysis among patients whose operations lasted 3 hours or less, the laparoscopic group fared better than did the open group in terms of 30-day mortality (1.1% vs 2.6%, P less than .001), cardiopulmonary and cerebrovascular complications (5.4% vs. 8.4%, P less than .001), and infectious complications (9.2% vs. 13.3%, P less than .001).
In contrast, among patients whose operations lasted more than 3 hours, differences in these outcomes were not significant. If anything, there was a trend toward a higher rate of infectious complications with laparoscopy.
To assess the role of preoperative risk factors, the investigators looked at NSQIP estimates of morbidity and mortality for all gastrointestinal and abdominal surgery by operative duration and including 37 preoperative risk factors, and found patterns differing from those in the study cohort.
Specifically, these estimates suggested mortality was consistently lower for procedures lasting more then 3 hours, whether laparoscopic or open. And the risk of infectious complications was constant for each type and less for laparoscopy, regardless of the operative duration.
Thus, "there is something other than preoperative risk factors causing an increase in mortality" with longer operative time for laparoscopic procedures in the study cohort, said Dr. Bailey, who disclosed no conflicts of interest related to the research. Also, "the increased infectious complications that we demonstrated are not related to the morbidity risk."
Patients in the laparoscopic group had a significantly higher risk of surgery lasting more than 3 hours if they had recently received radiation therapy (odds ratio, 6.5), were morbidly obese (3.0), or had peripheral vascular disease (2.5).
Hospital length of stay was consistently shorter with the laparoscopic approach, regardless of how long the operation lasted, according to Dr. Bailey.