It is Safe to Follow Patients with Medically Treated Type B Aortic Dissections

Abstract

Introduction - Type B aortic dissection (TABD) is a potentially life threatening disease and early endovascular treatment in uncomplicated cases has been reported. Urgent intervention is necessary in 1/3 of the cases for vascular complications. The promising short-term results of endovascular surgery seem to support the use of stent graft implantation in uncomplicated cases to prevent late aortic complications. Our aim was to analyse the results of late aorta related mortality in medically treated patients and to identify the factors that lead to late aortic interventions. Methods - Consecutive patients presented with acute uncomplicated TBAD in a tertiary care university centre were included in the study. The study period was 10 years (2006-2015). The data were analysed retrospectively. Initial and follow-up CT angiographic images were studied to measure maximal initial and follow-up aortic diameter and the change of the degree of false lumen thrombosis. Statistical methods: univariate analysis and life table calculations. Results - There were 43 patients (74% men), the average age at admission was 62.8 years. The mean follow-up time was 37.2 months. Seven patients (16.28%) had aortic surgery later (4 stent graft implantations, 2 open prosthetic graft implantations and 1 open thoracoabdominal aortic refenestration). Two patients (4.65%) had percutaneous interventions of aortic branches (1 renal artery stent implantation and 1 balloon angioplasty. None of the patients who required late surgery died in 30 days after admission. One patient (2.33%) died during follow up, related to a new dissection (surgery was not performed). CT angiography on admission showed completely patent false lumen in 83.3% of the cases, partial thrombosis was detected in 10% and complete thrombosis in 6.7%.During follow-up of the medically treated patients, the false lumen remained patent in 66.7%, 12.5% had partial thrombosis and 20.8% were thrombosed completely. The patients who required surgery later had patent false lumen in 16.7%, partial thrombosis in 50% and total thrombosis in 33.3%. The average maximum aortic diameter on admission was 41.34 mm (SD: 9.13) with no difference between the cohorts continue to have medical treatment or late surgery (p=0.89). The average increase of aortic diameter was 6.83 mm (SD: 5.31) in the group required surgery later and 5.71 mm (SD: 5.49) in patients without late surgery. The difference was not significant (p=0.16). Conclusion - Based on our low late aorta related mortality in patients treated medically for uncomplicated TABD, we consider the conservative approach and close follow-up (aggressive blood pressure control and serial images) to be a safe strategy in this cohort and we do not recommend early surgery. No death occured following elective late aortic intervention. The changes of the false lumen thrombosis had no relationship to late mortality and aortic intervention.