Late Referral and Patient Transfer is Associated with Worse Outcomes for Patients Presenting with Initially Uncomplicated Type B Aortic Dissections

Background: Acute type B aortic dissections (TBADs) can become complicated at any time point, necessitating surgical repair. We sought to investigate the effect of interhospital transfer on the development of delayed complications in acute type B aortic dissection (dcTBAD).Methods: All patients who presented with acute TBAD to a tertiary aortic center from 2015 to 2019 were analyzed. Patients were divided into initially complicated type B aortic dissection (icT-BAD) (0-24 hours from symptom onset), dcTBAD (25 hours to 14 days), and uncomplicated type B aortic dissection (ucTBAD) groups. Criteria for complicated dissection were aortic rupture, malperfusion, or rapid aortic growth. Demographics, patient history, the timing of pre-sentation, imaging findings, and clinical outcomes were compared between groups.Results: Of 120 acute TBADs included, 27 (22%) were initially complicated (aortic rupture, n = 9; malperfusion, n = 18). Twenty-one (18%) developed delayed complications (aortic rupture, n = 3; malperfusion, n = 14; rapid growth, n = 4) at a median of 7.0 [4.0, 9.0] days from symptom onset. Seventy-two (60%) remained uncomplicated. Overall, 111 (93%) presented as transfers from outside hospitals (icTBAD, n = 25; dcTBAD, n = 21; ucTBAD, n = 65). Of those, dcTBADs were more likely to have a prolonged delay between presentation to the outside hospital and referral to the tertiary center compared to ucTBADs (median = 1.00 [0.0, 5.0] days delayed vs. 0.00 [0.0, 0.0] days delayed; P < 0.001). Initially uncomplicated patients referred for transfer >= 24 hours from presentation went on to develop dcTBAD more often than those transferred in <24 hours (73% vs 13%; P < 0.001). Of dcTBADs, 38% had no high -risk features on initial imaging. Patients with dcTBAD had significantly longer length of stay (median = 12 vs 7 days; P = 0.006). In-hospital mortality was significantly higher in dcTBADs than ucTBADs (9.5% vs 0%; P = 0.047). In-hospital mortality was not significantly different be-tween dcTBADs and icTBADs (9.5% vs. 11%; P > 0.05).Conclusions: The incidence and consequence of dcTBADsare not insignificant. Late referral and transfer to a tertiary aortic center (>= 24 hours from initial presentation) was associated with dcTBADsrequiring surgical intervention. The development of dcTBADwas associated with increased length of stay and increased in-hospital mortality.