Continuous administration of recombinant human B-type natriuretic peptide can improve heart and renal function in patients after cardiopulmonary bypass surgery.

BACKGROUND

Any cardiac surgery under cardiopulmonary bypass (CPB) will induce ischemia-reperfusion injury and systematic inflammatory response, which may lead to exacerbation. Conventional therapy strategy is to use inotropes, diuretics and vasodilator drugs, yet, the therapeutic effects of which need to be improved. Recombinant human B-type natriuretic peptide (rhBNP) has been shown to be efficacious in the treatment of acute decompensated heart failure and acute myocardial infarction. However, the effects of rhBNP on patients carried out CPB surgery is unknown.

METHODS

We retrospect 357 patients carried out CPB surgery between Jan 1st 2014 and Dec 31st 2015 of our department. And according the use of rhBNP, these patients were divided into two groups: rhBNP group and control group. Patients in rhBNP group were received continuous intravenous rhBNP (0.0075-0.01 µg/kg/min) in 6 hours after CPB surgery, for a period of 72 h. Hemodynamic parameters were measured immediately after CPB surgery, and then at 2, 4, 8, 12 and 24 h after surgery. Blood samples were obtained immediately after surgery and thereafter once a day at 6:00 AM within the first 3 days after surgery. The daily urine volume as well as the time of tracheal intubation, ICU stay and chest drainage were also recorded.

RESULTS

The baseline characteristics and heart functions were well balanced between two groups, and no patient died in the surgery. It showed significant differences in time-dependent changes in both groups of MAP (P<0.0001, within groups), MPAP (P<0.0001, within groups), PAWP (P<0.0001, within groups), CI (P<0.0001, within groups), SVRI (P<0.0001, within groups), serum BNP (P<0.0001, within groups), CK-MB (P<0.0001, within groups), troponin (P<0.0001, within groups) and creatinine (P<0.0001, within groups). It also showed significant differences in time-dependent changes between the two groups of MAP (P=0.04, between groups), PAWP (P=0.04, between groups), serum troponin (P<0.0001, between groups), serum creatinine (P<0.0001, between groups) and urine volume (P<0.0001, between groups). Interestingly, our results showed that patients in rhBNP group tended to wean off the respirator half a day later than those in control group (P=0.05), while no significant difference showed in both the length of chest drainage time and intensive care unit stay between the two groups.

CONCLUSIONS

The administration of rhBNP can improve heart and renal function in patients underwent CPB surgery as well as accelerating the recovery from myocardial injury. But the prognosis of the patients who were administrated rhBNP did not improve in our study.