[Consideration of management of type B dissecting aneurysms of the thoracic aorta: clinical comparative study between surgical and medical treatments].

Between 1970 and 1989, 116 patients with type B dissecting aneurysms of the thoracic aorta were seen in our institution and affiliated hospitals. The patients were classified into 5 groups according to the acuity (acute vs chronic) and modes of therapy (surgical vs medical). Group I: 24 patients with acute B dissection were treated surgically during the acute stage. Group II: 21 patients with acute B dissection were initially treated with intensive medical therapy and followed by elective operation during the subacute stage. Group III: 22 patients with acute B dissection were treated medically. Group IV: 42 patients with chronic dissection were treated surgically. Group V: 7 patients with chronic B dissection were treated medically. The 5-year survival rates including early mortality were 70.5 +/- 9.4% for Group I, 88.9 +/- 7.5% for Group II, 68.3 +/- 11.2% for Group III, 64.6 +/- 8.4% for Group IV and 71.4 +/- 17.1% for Group V. The 5-year survival rates of Group II was significantly better than those of Group I, III and IV, respectively. The present data suggests that acute type B dissection without complications (bleeding, visceral or lower limbs ischemia) should be treated initially with intensive medical therapy and then followed by elective operation during the subacute stage, if the false lumen were not thrombosed.