Comparison of aortic remodelling after conservative treatment or thoracic endovascular repair in type B dissections

OBJECTIVES: Our aim was to compare aortic remodelling in type B dissections after thoracic endovascular aortic repair (TEVAR) or conservative treatment. METHODS: We conducted a retrospective analysis of computed tomography (CT) data sets at dissection onset and at the last follow-up in a group with conservative (group A) and TEVAR treatment (group B). An additional analysis of the preoperative CT images was performed in patients from group A, who were converted to TEVAR during follow-up. Diameters and lengths of all aortic segments were measured and growth rates were calculated. RESULTS: We included 74 patients: 50 patients in group A (follow-up time: 1625 +/- 209 days) and 24 patients in group B (follow-up time: 554 +/- 129 days). The mean aortic diameter growth rate was significantly higher in group A than in group B in the mid-descending aorta (A: +7 mm/year; B: -4 mm/year; P = 0.003). Length growth difference was only present in the abdominal aortic segment and was more pronounced in group A (+2 vs +/- 0 mm/year; P = 0.009). The conversion rate from conservative treatment to TEVAR was 36% (n = 18). A false lumen diameter of >22mm at baseline was associated with a higher rate of conversion (P = 0.036). After conversion, the mean growth rate in the proximal descending and mid-descending aorta decreased from preoperative +11 and +18 mm/year to postoperative -9 and -14mm/year, respectively (P < 0.001). CONCLUSIONS: In acute type B dissections, TEVAR stops aortic enlargement in the thoracic aorta, but promotes distal dilatation compared to the conservative treatment group. After conversion to TEVAR in conservatively pretreated chronic type B dissections, a more pronounced diameter decrease in the descending aorta was observed than in patients treated in the acute phase.