Is vasoplegic syndrome more prevalent with open-heart procedures compared with isolated on-pump CABG surgery?

Postoperative vasoplegic syndrome (PVS) is a frequent complication and can affect the early postoperative course. Our study investigated the incidence and risk factors of PVS after on-pump isolated coronary artery grafting bypass (CABG) and on-pump open-heart surgery. A total of 629 patients underwent on-pump cardiac surgery from November 21, 2005, to June 9, 2006, at our institution. Of those, 334 patients underwent on-pump isolated CABG and 295 patients had open-heart surgery. PVS was defined based on the recognized criteria. Multivariate logistic regression analysis was used to identify the risk factors for PVS. The overall incidence of PVS was 11.7%. The incidence in isolated on-pump CABG surgery was 6.9% and 17.0% in open-heart surgery (P<.01). In multivariate analysis, isolated CABG reduced by half the incidence of PVS [odds ratio (OR)=0.45, P=.02]; preoperative left ventricular ejection fraction (EF) <35% was identified as an independent predictor of PVS (OR=2.1, P=.01), and a protective effect of female gender for PVS was observed (OR=0.4, P=.01). The association between angiotensin-converting enzyme inhibitors and other preoperative medical treatments was not confirmed by our study. In conclusion, PVS occurred less often after isolated CABG surgery than after open-heart surgery. Advanced age and low preoperative EF strongly predicted PVS.

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.

BPDZ 154 activates adenosine 5'-triphosphate-sensitive potassium channels: in vitro studies using rodent insulin-secreting cells and islets isolated from patients with hyperinsulinism.

A novel ATP-sensitive potassium channel (K(ATP)) channel agonist, BPDZ 154 (6,7-dichloro-3-isopropylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide), was synthesized, and its effects on insulin-secreting cells were evaluated using electrophysiology, (86)Rb(+) and (45)Ca(2+) efflux, and RIA determinations of insulin secretion. BPDZ 154, an analog of diazoxide, inhibited both glucose-induced insulin secretion from isolated perifused islets and the secretion of insulin induced by glucose and tolbutamide. These effects were mediated by the activation of ATP-sensitive potassium channels because BPDZ 154 induced a concentration-dependent increase in channel activity that was inhibited by the sulfonylurea tolbutamide and the imidazoline efaroxan. In beta-cells isolated from patients with either nontypical hyperinsulinism (preserved K(ATP) channel function) or from the control areas of the pancreas of patients with focal hyperinsulinism, BPDZ 154 activated K(ATP) channels and was found to be more effective and less readily reversible than diazoxide. By contrast, it was not possible to activate K(ATP) channels by either diazoxide or BPDZ 154 in beta-cells from patients with hyperinsulinism as a consequence of defects in K(ATP) channel function. In beta-cells isolated from a patient with pancreatic insulinoma, K(ATP) channels were readily recorded and modulated by BPDZ 154. These data suggest that BPDZ 154 or BPDZ 154-like compounds may have therapeutic potential in the treatment of certain forms of hyperinsulinism.