ABSTRACT
<b>Background</b> : Endovascular treatment of the thoracic aorta (TEVAR) for type B aortic dissection is reported to be effective if the interval between the onset and the procedure is relatively short. However, the optimal timing for TEVAR is still controversial. <b>Method</b> : From December 2008 to April 2015, we experienced 46 TEVARs for type B aortic dissection. The interval between onset and TEVAR was within 3 months in 15 cases (Group A), from 3 months to 1 year in 10 cases (Group B), and more than 1 year in 21 cases (Group C). <b>Result</b> : Primary success was obtained in all cases, and no new intimal tear was formed during the procedure. There was no hospital death. At the time of discharge, disappearance of ULP or thrombosed thoracic false lumen occurred significantly more frequently in Group A (93%) than in Group B (50%) and Group C (43%) (<i>p</i><0.05). At 6 months, the rate of the patients with reduced aneurysm diameter more than 5 mm was significantly higher in Group A (87%) and Group B (70%) than in Group C (19%) (<i>p</i><0.05). Three cases of Group C had enlargement of the aneurysm despite of TEVAR, and graft replacement of thoracoabdominal aorta was performed in one of the cases. <b>Conclusion</b> : For type B aortic dissection, TEVAR is more effective if performed within 3 months from the onset.