Atrial Natriuretic Peptide in Postoperative Acute Renal Failure

Abstract

Acute renal dysfunction is a common postoperative complication following cardiac or major vascular surgery [1–4]. Ten to twenty percent of patients with acute renal dysfunction after cardiovascular surgery may develop dialysis-dependent acute renal failure, with a reported mortality of 30–60 % [1–4]. Dialysis-dependent acute renal failure has been considered an independent risk factor for early mortality in such patients [5, 6]. The pathogenesis of postoperative acute renal failure is believed to be predominantly a consequence of renal hypoperfusion and ischemia, particularly of the renal medulla [7, 8]. The renal medullary concentrating mechanism, requiring large amounts of oxygen, in combination with the relatively low medullary blood flow, renders the renal medulla hypoxic, with low tissue PO₂ levels, already under normal conditions [7]. The renal medulla, particularly the outer portion, is, therefore, sensitive to acute renal ischemia. Perioperative acute renal failure may also be related to factors including nephrotoxin exposure (heme pigments, inflammatory cytokines), embolism, and aortic cross-clamping. In spite of recent advances, outcomes from cardiovascular surgery-related acute renal failure have not changed substantially in the last decades and novel treatment strategies for prevention/treatment of perioperative acute renal dysfunction are, therefore, urgently needed.