Regional Transport System for Acute Aortic Syndromes
What are the outcomes of patients with acute aortic syndrome (AAS) during and after transfer to a regional aortic center by a rapid transport system?
The medical records were reviewed for patients with AAS who were transferred by a rapid transport system to a regional aortic center. 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.
During the 18-month period December 2013–July 2015, 183 patients were transferred by a rapid transport system, including 148 (81%) patients 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 = 0.026), coronary artery disease (p = 0.030), prior myocardial infarction (p = 0.049), prior coronary revascularization (p = 0.002), SVSCSS >8 (p < 0.001), abdominal pain (p = 0.002), systolic blood pressure <90 mm Hg at sending hospital (p = 0.001), diagnosis of aortic aneurysm (p = 0.013), systolic blood pressure <90 mm Hg in the intensive care unit (p < 0.001), and APACHE II score >10 (p = 0.004). 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 = 0.001) was independently associated with an increase in system-related mortality on multivariate analysis.
The authors concluded that implementation of a rapid transport system, regardless of mode or distance, can facilitate effective transfer of patients with AAS to a regional aortic center; and that an SVSCSS >8 predicted an increased system-related mortality and may be a useful metric to assess the appropriateness of patient transfer.
Institutional expertise and resources required to comprehensively manage patients with AAS are limited, suggesting that regionalization of treatment potentially could improve outcomes. Regionalization of treatment requires the development of transport systems that can safely and rapidly move an acutely ill patient from a transferring hospital to a regional referral center. This study suggests that the implementation of such a regional rapid transport system to facilitate the transfer and care of patients with AAS can be associated with favorable clinical outcomes.
Keywords: Aortic Aneurysm, Aortic Aneurysm, Abdominal, Aortic Rupture, Blood Pressure, Coronary Artery Disease, Intensive Care Units, Myocardial Infarction, Transportation
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