Management of patients with acute aortic syndrome through a regional rapid transport system

Abstract

Objective: The objective of this study was to describe the outcomes of patients with acute aortic syndrome (AAS) during and after transfer to a regional aortic center by a rapid transport system.

Methods: Review of patients with AAS who were transferred by a rapid transport system to a regional aortic center was performed. Data regarding demographics, diagnosis, comorbidities, transportation, and hospital course were acquired. Severity of existing comorbidities was determined by the Society for Vascular Surgery Comorbidity Severity Score (SVSCSS). The Acute Physiology and Chronic Health Evaluation II (APACHE II) score assessed physiologic instability on admission. Risk factors associated with system-related (transfer and hospital) mortality were identified by univariate and multivariate linear regression analysis.

Results: During a recent 18-month period (December 2013-July 2015), 183 patients were transferred by a rapid transport system; 148 (81%) patients were transported by ground and 35 (19%) by air. Median distance traveled was 24 miles (range, 3.6-316 miles); median transport time was 42 minutes (range, 10-144 minutes). Two patients died during transport, one with a type A dissection, the other of a ruptured abdominal aortic aneurysm. There were 118 (66%) patients who received operative intervention. Median time to operation was 6 hours. Type B dissections had the longest median time to operation, 45 hours, with system-related mortality of 1.9%; type A dissections had the shortest median time, 3 hours, and a system-related mortality of 16%. Overall, system-related mortality was 15%. On univariate analysis, factors associated with system-related mortality were age ≥65 years (P = .026), coronary artery disease (P = .030), prior myocardial infarction (P = .049), prior coronary revascularization (P = .002), SVSCSS of >8 (P < .001), abdominal pain (P = .002), systolic blood pressure <90 mm Hg at sending hospital (P = .001), diagnosis of aortic aneurysm (P = .013), systolic blood pressure <90 mm Hg in the intensive care unit (P < .001), and APACHE II score >10 (P = .004). Distance traveled and transport mode and duration were not associated with increased risk of system-related mortality. Only SVSCSS of >8 (odds ratio, 7.73; 95% confidence interval, 2.32-25.8; P = .001) was independently associated with an increase in system-related mortality on multivariate analysis.

Conclusions: Implementation of a rapid transport system, regardless of mode or distance, can facilitate effective transfer of patients with AAS to a regional aortic center. An SVSCSS of >8 predicted an increased system-related mortality and may be a useful metric to assess the appropriateness of patient transfer.