Background: Medical therapy is the cornerstone of managing uncomplicated type B aortic dissections (uTBAD), however there are limited guidelines on its implementation. This study aimed to investigate variations in the interpretation and implementation of medical therapy among principal investigators of an ongoing international randomised clinical trial on uTBAD management. Methods: A cross-sectional questionnaire-based study was conducted among all principal investigators participating in the Scandinavian trial of Uncomplicated Aortic Dissection Therapy (SUNDAY) trial across 7 countries. A secure online survey was distributed and entered into REDCap, collecting categorical data on different aspects of medical therapy, including therapy targets, reporting standards, medical management and investigations. Results: A total of 34 of 46 investigators responded (74%). While 31 (91%) agreed upon blood pressure targets of less than 120mmHg, refractory hypertension was defined as blood pressure exceeding 140mmHg by 12 (35%), with 17 (50%) considering the number of antihypertensives used to determine refractory hypertension of which 8 (24%) set this at >3, and 9 (27%) at >5. The upper limit for heart rate was agreed as 60 bpm by 20 (59%). There was no agreement on the definition of refractory pain, with 7 (21%) not even considering it in decision-making. There was notable variation in reporting standards regarding chronicity, with 11 (32%) deeming hyperacute to be <24hrs, 13 (38%) deeming it <48hrs and 5 (15%) not considering it at all. 29 (85%) stated that they have a standardised hospital protocol for medical therapy for acute uTBAD. There was general agreement on escalation of anti-hypertensives in acute uTBAD with 30 (88%) starting with IV labetalol as first line, followed by calcium channel antagonists by 13 (38%) as second- and third-line treatments. Adjunctive medications were used consistently with 20 (59%) commenced statins as part of medical therapy and 22 (65%) commenced life-long single antiplatelets.