Risk factors for perioperative mortality after revascularization for acute aortic occlusion

Abstract

Objective: Acute aortic occlusion (AAO) is a life-threatening event necessitating prompt revascularization to the pelvis and lower extremities. Because of its uncommon nature, outcomes after revascularization for AAO are not well characterized. Our aim was to describe the perioperative morbidity and mortality associated with revascularization and to identify the patients at highest risk.

Methods: A retrospective chart review was performed of patients who presented to our institution from 2006 to 2017 with acute distal aortic occlusion. Patients with a prior aortofemoral bypass were excluded, but those with aortoiliac stents were included. Baseline demographics and comorbidities, preoperative clinical presentation and imaging, procedural details, and postoperative hospital course were reviewed. The primary outcome was 30-day mortality, and major complications were evaluated as secondary outcomes. Logistic regression models were constructed to identify factors associated with 30-day mortality.

Results: We identified 65 patients who underwent revascularization for AAO. Median age was 63 years (range, 35-89 years), and 64.6% were male; 56.4% of patients presented within 24 hours of symptom onset, and 43.8% were treated within 6 hours of presentation. There were particularly high rates of prior coronary artery disease (62.3%) and chronic obstructive pulmonary disease (41.0%); 18.5% had prior iliac stents. Preoperative imaging in 44 patients showed occlusion of the inferior mesenteric artery in 36.0% and both internal iliac arteries in 34.7%. Treatments for revascularization included axillobifemoral bypass (55.4%), aortoiliac thromboembolectomy (15.4%), aortobifemoral bypass (13.9%), and aortoiliac stenting (15.4%). Overall 30-day mortality was 27.7% and was not affected by treatment modality. Mortality was highest in patients older than 60 years (40.5% vs 10.7%; P = .01) and those presenting with lactate elevation (45.5% vs 5.9%; P = .004) or motor deficit in at least one extremity (36.6% vs 9.5%; P = .03). Univariate predictors of 30-day mortality were age ≥60 years (odds ratio [OR], 5.68; 95% confidence interval [CI], 1.45-22.26; P = .01), presentation with motor deficit (OR, 5.48; 95% CI, 1.12-26.86; P = .04), presentation with elevated lactate level (OR, 13.33; 95% CI, 1.58-11.57; P = .02), history of prior stroke (OR, 4.80; 95% CI, 1.21-18.97; P = .03), and bilateral internal iliac artery occlusion (OR, 7.11; 95% CI, 1.54-32.91; P = .01). At least one postoperative complication was observed in 78.5% of patients, including acute kidney injury (56.9%, with 21.5% requiring hemodialysis), respiratory complications (46.2%), cardiovascular complications (33.9%), major amputation (15.4%, bilateral in 7.7%), and bowel ischemia (10.8%).

Conclusions: Even with prompt revascularization and despite the chosen treatment modality, AAO carries high risk of mortality and numerous life-threatening complications. Older patients presenting with elevated lactate levels, motor deficit, and bilateral internal iliac artery occlusions are at the highest risk of perioperative mortality. These factors may aid in risk stratification and managing expectations in this critically ill population.

Keywords: Acute aortic occlusion; Aortobifemoral bypass; Aortoiliac thromboembolectomy; Axillobifemoral bypass.