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Circulation. 2019 Oct 8;140(15):1239-1250. doi: 10.1161/CIRCULATIONAHA.118.038867. Epub 2019 Oct 7.

Interfacility Transfer of Medicare Beneficiaries With Acute Type A Aortic Dissection and Regionalization of Care in the United States.

Author information

1
Departments of Cardiothoracic Surgery (A.B.G., P.C., B.L., M.P.F., Y.J.W.), Department of Medicine, Stanford University, CA.
2
Health Research and Policy (A.B.G., P.C.), Department of Medicine, Stanford University, CA.
3
Stanford Prevention Research Center (M.B.), Department of Medicine, Stanford University, CA.
4
Quantitative Sciences Unit (J.L., J.R.), Department of Medicine, Stanford University, CA.

Abstract

BACKGROUND:

The feasibility and effectiveness of delaying surgery to transfer patients with acute type A aortic dissection-a catastrophic disease that requires prompt intervention-to higher-volume aortic surgery hospitals is unknown. We investigated the hypothesis that regionalizing care at high-volume hospitals for acute type A aortic dissections will lower mortality. We further decomposed this hypothesis into subparts, investigating the isolated effect of transfer and the isolated effect of receiving care at a high-volume versus a low-volume facility.

METHODS:

We compared the operative mortality and long-term survival between 16‚ÄČ886 Medicare beneficiaries diagnosed with an acute type A aortic dissection between 1999 and 2014 who (1) were transferred versus not transferred, (2) underwent surgery at high-volume versus low-volume hospitals, and (3) were rerouted versus not rerouted to a high-volume hospital for treatment. We used a preference-based instrumental variable design to address unmeasured confounding and matching to separate the effect of transfer from volume.

RESULTS:

Between 1999 and 2014, 40.5% of patients with an acute type A aortic dissection were transferred, and 51.9% received surgery at a high-volume hospital. Interfacility transfer was not associated with a change in operative mortality (risk difference, -0.69%; 95% CI, -2.7% to 1.35%) or long-term mortality. Despite delaying surgery, a regionalization policy that transfers patients to high-volume hospitals was associated with a 7.2% (95% CI, 4.1%-10.3%) absolute risk reduction in operative mortality; this association persisted in the long term (hazard ratio, 0.81; 95% CI, 0.75-0.87). The median distance needed to reroute each patient to a high-volume hospital was 50.1 miles (interquartile range, 12.4-105.4 miles).

CONCLUSIONS:

Operative and long-term mortality were substantially reduced in patients with acute type A aortic dissection who were rerouted to high-volume hospitals. Policy makers should evaluate the feasibility and benefits of regionalizing the surgical treatment of acute type A aortic dissection in the United States.

KEYWORDS:

aneurysm, dissecting; causality; confounding factors, epidemiology; epidemiology; patient transfer; surgery

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