[A correlation between atrial natriuretic peptide, brain natriuretic peptide, and perioperative cardiac and renal functions in open heart surgery].

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are homeostatic hormones secreted from the human heart which protect both cardiac and the renal function. It is well known that these hormones increase in patients along with increases in the severity of congestive heart failure or acute myocardial infarction. However, as yet there are no reports in the literature on changes of the secreted level of ANP or BNP in surgical patients undergoing cardiopulmonary bypass (CPB). We evaluated the relationship between ANP, BNP, and perioperative cardiac and renal functions in patients with heart failure caused by CPB. We selected 45 patients of elective open heart surgery. We measured plasma level of ANP in all 45 cases, and BNP in 18 cases at preoperation, postoperation, and postoperatively three days after, respectively. At the same time, the cardiac index (CI) was measured. These cases were divided into the following groups. Group A1 (n = 23): cases in which the preoperative ANP was less than 40 pg/ ml. Group A2 (n = 22): cases in which the preoperative ANP was more than 40. Group B1 (n = 8): cases in which the preoperative BNP is increased to the level of 5 times as mach as the normal level. Group B2 (n = 8): cases in which the preoperative BNP is increased to the level of 5 times as much as the normal level. Group B2 (n = 10): cases in which the preoperative BNP was more than that of 10 times as mach as normal level. We then carried out a comparative study of the perioperative cardiac and renal functions in group A1 and A2, and group B1 and B2, respectively. In the terms of preoperative cardiac and renal function, there were no significant differences between groups A1 and A2, and there were no significant differences in urinary volume during CPB or post operative CI. However, the urinary volume during CPB of group B1 was significantly more than that of B2. Furthermore, the incidence of postoperative CI in group B1. Furthermore, the incidence of postoperative CI in group B1 was significantly higher than in B2. The preoperative and post operative third day BNP level had significant negative correlations with postoperative CI and postoperative third day CI, respectively (r = -0.641, -0.514, p = 0.008, 0.012). The postoperative ANP and BNP levels tend to a mean level roughly similar to one another because of the easing of cardiac stress by surgery and postoperative management. According to these results and several instances in the literature, a preoperative high BNP is considered to suggest a potential perioperative risk for cardiac and renal function. We conclude that determination of the plasma BNP level can be helpful for decisions related to CPB flow and measures taken to enhance cardiac and renal protection during surgery, and therefore is a useful reference for perioperative management.