Synthetic human alpha-atrial natriuretic peptide improves the management of postoperative hypertension and renal dysfunction after the repair of abdominal aortic aneurysm

Abstract

Objective: Delayed hypertension (HT) and renal dysfunction (RD) are observed after aortic operations accompanied by infra-renal aortic cross-clamping (AXC). Atrial natriuretic peptide (ANP) has effects on vasodilation and renal protection, and we examined the hypothesis that synthetic human alpha-ANP (hANP) improves the postoperative management for abdominal aortic aneurysm (AAA).

Methods: Fifty patients undergoing elective aneurysmectomy for infrarenal-AAA between 1998 and 2001 (M:F = 43:7, mean age 70.5 +/- 7.7 years) were randomly allocated to one of 2 groups; Group H (n = 24) received hANP immediately after operation (initial dose: 0.025 microg/kg/min), and Group C (n = 26) served as a control group.

Results: All patients in Group C required nicardipine hydrochloride (4.41 +/- 1.68 mg/h) for prevention of postoperative HT, whereas only 6 patients in Group H required the increase in hANP dose due to HT (P < 0.0001). Maximum hANP dose was 0.035 +/- 0.019 microg/kg/min. Group H showed significantly smaller furosemide dosage in the initial 3 days (H vs. C; 9.2 +/- 11.0 vs. 58.8 +/- 41.5 mg, P < 0.0001), significantly lower peak-Crn (H vs. C; 1.16 +/- 0.53 vs. 2.58 +/- 1.42 mg/dL, P < 0.0001), and significantly lower plasma renin-activity (7.09 +/- 2.38 vs. 11.52 +/- 4.89 ng/mL/h, P = 0.0002) and aldosterone (51.6 +/- 12.7 vs. 81.2 +/- 34.2 pg/mL, P = 0.0002) on the first postoperative day than Group C did.

Conclusions: These results imply that renin-angiotensin system may play a role in the incidence of postoperative HT and RD, and suggest that hANP infusion is a simple, reliable, and effective method for management during the immediate period after AAA operations.