Temporary worsening of renal function after aortic surgery is associated with higher long-term mortality

Abstract

Conclusion: Temporary worsening of renal function after open surgery for abdominal aortic aneurysm (AAA) is associated with an increased long-term mortality rate. Summary: The authors sought to determine the effects of temporary renal dysfunction on the long-term mortality rate in patients undergoing AAA surgery. From January 1995 to June 2006, 1324 patients underwent elective open AAA repair in a single center in Rotterdam. Creatinine clearance was measured preoperatively and on postoperative days 1, 2, and 3. The patients were then divided into three groups. Group 1 had improved or unchanged renal function. Group 2 had temporary worsening of renal function with a >10% decrease on day 1 or 2, and then recovery ≤10% of baseline by day 3. Group 3 patients had persistent worsening of renal function as defined by a >10% decrease in creatinine clearance compared with the baseline value. The 30-day mortality rates in groups 1, 2, and 3 were 1.2%, 5%, and 12.6%, respectively. Adjusting for postoperative complications and baseline characteristics, the 30-day mortality rate was greatest in the patients with persistent worsening of renal function (hazard ratio (HR), 7.3; 95% confidence interval [CI], 2.7-19.8). Those who had temporary worsening of renal function also had an increased mortality risk (HR, 3.7; 95% CI, 1.4-9.9). Follow-up was for 6.0 ± 3.4 years. During follow-up, 348 patients (36.5%) died. The HR for late death was 1.7 (95% CI, 1.3-2.3) in the patients who had persistent worsening of renal function. For those who had temporary worsening of renal function, the HR for death was 1.5 (95% CI, 1.2-1.4). There was a significant association between perioperative blood loss and worsening of renal function (P < .001) and between length of suprarenal aortic clamping and worsening of renal function (P < .001). There was also a greater incidence of hypertension in the patients with temporary and persisting renal dysfunction (P < .001). Comment: Another recent study suggested minimal changes in renal function after cardiothoracic surgery had little impact on long-term prognosis (J Am Soc Nephrol 2004;15:1597-605). The current study reaches an opposite conclusion. Although this study was retrospective, the mean follow-up was long (6 years) and the number of patients was large (n = 1324). It is reasonable, therefore, to conclude that any significant worsening of perioperative renal function in an AAA patient carries an adverse prognosis both in the near- and long-term. Although it seems nice when transient renal dysfunction after AAA surgery returns to baseline levels, it doesn’t appear to do the patient any good.