ORal anticoagulation risks Late Aortic intervention in Conservatively Managed Type B Aortic Dissection (ORCA-Study).

OBJECTIVE: Single-center retrospective cohort study to evaluate the impact of oral anticoagulation (OAC) on long-term outcomes of conservatively managed acute type B aortic dissection (TBAD).

METHODS: Clinical and morphological data of eligible patients from a high-volume vascular center from January 1st, 2003 through December 31st, 2020 were evaluated. Patients were excluded for: type A or non-A-non-B dissection, isolated abdominal dissection, intramural haematoma, connective tissue disease. The primary outcome was freedom from late aortic events (intervention, rupture, mortality). Secondary outcomes included spinal cord ischaemia, bleeding, reno-visceral artery occlusion, ilio-femoral intervention, dissection propagation, aortic growth, aortic remodelling, deterioration of false lumen thrombosis as well as 30-day and overall mortality. Time-to-event was analyzed using multivariable Cox proportional hazard models with OAC as time-varying covariate and mortality as a competing risk. The impact of OAC was adjusted for potential confounding factors.

RESULTS: 69 patients (50 males, median age 65 (IQR: 58 to 72) years) were enrolled. Median follow-up was 49.3 (28 to 92) months. 47 patients (68%) received OAC at any time throughout the follow-up for a median length of 26 (11 to 61) months. Late aortic events occurred in 28 patients (41%) including intervention (n = 27, 39%) and rupture (n = 1, 1%). OAC was associated with more late aortic events (HR 3.94, 95%-CI 1.06-14.6, p = 0.040). Secondary outcomes were not associated with OAC.

CONCLUSIONS: Our data suggests a relation of OAC therapy with an increased risk for late aortic interventions. TBAD should not be the primary indication for OAC and patients with OAC for other indications require frequent follow-up imaging.