Is incidence of postoperative vasoplegic syndrome different between off-pump and on-pump coronary artery bypass grafting surgery?

OBJECTIVE: Postoperative vasoplegic syndrome (PVS) is a potentially lethal condition with increased mortality and other postoperative morbidities. Many previous studies have examined the outcomes associated with on-pump coronary artery bypass grafting (CABG) surgery, little is known about the incidence of PVS after off-pump CABG.

METHODS: From November 21, 2005 to June 9, 2006, 334 patients underwent isolated on-pump CABG and 362 had off-pump CABG surgery. Perioperative variables were retrospectively compared between on-pump and off-pump CABG surgery using univariate analysis. Significant variables were included into a stepwise regression model to ascertain their independent impact on the incidence of PVS.

RESULTS: The incidence of PVS in isolated on-pump CABG was 6.9%; in off-pump CABG was 2.8% (p=0.01). However, in multivariable models adjusted for confounders, on-pump CABG did not reach statistical significance as a risk factor of PVS (OR=2.3, 95% CI 0.94-5.78; p=0.07). In on-pump CABG, preoperative left ventricular EF less than 35% (OR=3.6; p=0.02) and increased body mass index (OR=1.1; p=0.04) were identified as risk predictors of PVS; whereas elective surgery (OR=0.2; p=0.02) and preoperative use of beta-blockers (OR=0.21; p=0.02) were associated with a decreased rate of PVS. PVS was associated with longer ICU stay (OR=6.0; p<0.01), postoperative ventilation (OR=4.6; p<0.01), and hospital stay (OR=2.62; p=0.03). There was a stronger association between preoperative ACE inhibitors therapy and increased risk of PVS in off-pump CABG surgery (OR=4.52, 95% CI 0.95-21.67; p=0.06) than in on-pump CABG surgery (OR=1.06, 95% CI 0.35-3.19; p=0.91), but neither of them reaches statistical significance.

CONCLUSIONS: The incidence of PVS after off-pump CABG surgery was significantly lower than after on-pump CABG surgery.