NEW YORK — Off-pump coronary surgery cut mortality compared with on-pump surgery in a retrospective assessment of 270 patients with an extremely low ejection fraction.
The study reviewed all 5,765 patients who underwent coronary artery surgery at Lenox Hill Hospital in New York during January 1995-October 2004. The overall in-hospital mortality in all of these patients was 26%, reported Ramachandra C. Reddy, M.D., and his associates in a poster at the annual meeting of the International Society for Minimally Invasive Cardiothoracic Surgery.
The group included 270 patients who had a left ventricular ejection fraction of less than 20% when they were examined prior to coronary bypass surgery. Within this subgroup, 142 patients underwent surgery on cardiopulmonary bypass (on pump), and 128 had their surgery done without bypass (off pump). Assignment to the on-pump or off-pump groups was not done on a randomized basis. Eight of the off-pump patients were converted to on-pump patients during their surgery, but their follow-up results were counted in the off-pump group.
The on-pump and off-pump groups had very similar demographic and clinical profiles. The off-pump patients had a significantly higher prevalence of diabetes, 58%, compared with a 42% prevalence in the on-pump patients. The off-pump group also had a higher prevalence of a history of stroke, though this was not a significant difference—13% off pump and 6% on pump, respectively. The incidence of postsurgical complications was also very similar in the two subgroups. However, postsurgical mortality was 4.7% in the off-pump patients and 11.3% in the on-pump patients, a statistically significant difference, reported Dr. Reddy, a cardiothoracic surgeon at Lenox Hill Hospital.
In a multivariate logistic regression analysis adjusted for baseline differences between groups, on-pump coronary bypass surgery was associated with a 2.6-fold increased risk of death compared with off-pump surgery in this high-risk group.
Another difference between these two techniques of cardiopulmonary bypass was seen in the length of hospitalization following surgery. The on-pump patients had an average, postsurgical length of stay of 13 days, compared with an average of 10 days in the off-pump patients, a statistically significant difference.