Postoperative renal dysfunction independently predicts late mortality in patients undergoing aortic reconstruction

Abstract

Objective: Preoperative chronic kidney disease (CKD) has been shown to predict postoperative renal complications and mortality after open aortic surgery; the impact of postoperative renal complications less severe than permanent dialysis are unknown. We evaluated the impact of postoperative renal dysfunction severity on survival using a regional quality improvement registry.

Methods: Patients undergoing intact open aortic reconstruction in the Vascular Study Group of New England registry (2003-2012) were stratified by severity of postoperative renal complications; none, creatinine increase of greater than 0.5 mg/dL (incCr), or any hemodialysis (HD). Predictors of renal dysfunction and impact of renal complications on survival were analyzed using multivariable methods.

Results: We included 2695 patients, of which 65% (n = 1733) underwent open abdominal aortic aneurysm repair, and 35% (n = 962) open aortoiliac reconstruction. At baseline, 15% of patients had preoperative moderate CKD and 1.2% had severe CKD. Postoperative renal complications of incCr occurred in 8.5% of patients, and 1.5% required HD. Multivariable cumlogit regression identified severe baseline CKD (odds ratio [OR], 15; 95% confidence interval [CI], 6.4-34; P < .001, moderate CKD (OR, 2.8; 95% CI, 1.9-3.3; P < .001), suprarenal clamp use (OR, 2.2; 95% CI, 1.6-2.9; P < .001), perioperative vasopressor requirements (OR, 2.2; 95% CI, 1.6-2.9; P < .001), operating time (OR, 1.004 per minute; 95% CI, 1.003-1.006; P < .001), and chronic obstructive pulmonary disease (OR, 1.5; 95% CI, 1.2-1.8; P < .001) as independent predictors of worsening strata of postoperative renal dysfunction. Multivariable logistic regression analysis showed that patient age (OR, 1.06 per year; 95% CI, 1.01-1.1; P = .01), baseline chronic obstructive pulmonary disease (OR, 1.6; 95% CI, 1.2-2.2; P < .01), incCr (OR, 3.7; 95% CI, 1.8-7.4; P = .009), and HD (OR, 4.8; 95% CI, 1.8-12.7); P = .009) independently increased 30-day mortality. Risk-adjusted multivariable Cox regression showed that incCr (hazard ratio, 1.8; 95% CI, 1.3-2.6; P < .001) and HD (hazard ratio, 4.4; 95% CI, 2.8-6.9; P < .001) increased risk of late death independent of a variety of other clinical variables, including baseline CKD. The 5-year survival was lower (log-rank P < .001) in patients with incCr (66% ± 4%), and HD (38% ± 10%) compared with those with no renal complications (77% ± 1%).

Conclusions: Increasing severity of postoperative renal dysfunction independently predicts increased risk of late mortality after open aortic surgery. Perioperative measures to decrease renal complications may potentially prolong the survival of patients after open aortic surgery.