['The goal of the retrospective study was to relate the site of the primary entry tear in acute type B aortic dissections to the presence or development of complications.', 'A consecutive series of 52 patients referred with acute type B aortic dissection was analysed with regard to the location of the primary entry tear (convexity or concavity of the distal aortic arch) using the referral CT scans at the time of diagnosis. These findings were related to the clinical outcome as well as to the need for intervention.', 'Twenty-five patients (48%) had the primary entry tear located at the convexity of the distal aortic arch, whereas 27 patients (52%) had the primary entry tear located at the concavity of the distal aortic arch. Twenty per cent of patients with the primary entry tear at the convexity presented with or developed complications, whereas 89% had or developed complications with the primary entry tear at the concavity (P < 0.001). Furthermore, in patients with complicated type B aortic dissection, the distance of the primary entry tear to the left subclavian artery was significantly shorter as in uncomplicated patients (8 vs. 21 mm; P = 0.002). In Cox regression analysis, a primary entry tear at the concavity of the distal aortic arch was identified as an independent predictor of the presence or the development of complicated type B aortic dissection.'] Does the location of the primary entry tear in acute type B aortic dissection affect early outcome?