The impact of interhospital transfer on mortality for acute aortic dissections

Background — There is a time-sensitive increase to mortality for acute type A dissections, yet interhospital transfer has not shown to increase operative death. Operative death does not account for all deaths attributable to transfer. We sought to determine the impact of transfer on mortality for all patients transferred with acute aortic dissections.

Methods — A retrospective study of de-identified health data between April 2003 and March 2020 for Ontario, Canada (14.7 million population) was performed to identify all patients hospitalized with acute aortic dissections. Non-transfers and interhospital transfers were reviewed and characteristics associated with transfer assessed. Associations between transfer and death were estimated using modified Poisson regression.

Results — There were 6,218 acute aortic dissections (type A, n=2,641; type B, n=3,577). For 148 hospitals, 11 had onsite cardiac surgery. There was a 2.02-fold (95% CI 1.66 – 2.45) increased risk of mortality for type A dissection patients transferred to a cardiac surgery hospital for surgical consideration (32.6%), relative to those at a cardiac surgery hospital who had surgery (16.3%). For patients that transferred alive and had surgery, there was no mortality difference (18.1% vs. 16.3%, p=0.37). A nontransfer palliation strategy was more likely for females (p<.001), age >75 (p<.001), rural residence (p<.008), and increased Charlson index (p<.001). Type B dissections showed no difference in mortality across non-cardiac and tertiary hospitals (9.8% vs. 10.2%, p=0.70).

Conclusions — Transfers for acute type A dissections were associated with increased mortality. Palliation instead of transfer for surgical consideration was more common for women.