Graft replacement of aneurysm in descending thoracic aorta: results without bypass or shunting

During the 24-year period from 1956 to 1980, 148 patients with aneurysms confined to the thoracic aortic segment, bounded above by the left subclavian artery and below the diaphragm, were treated with replacement therapy. From 1956 to 1967, 36 patients were treated by use of temporary bypass or shunts which carried a 6% incidence of paraplegia and a mortality rate of 22%. From 1962 to 1980, 112 patients were treated without shunts or bypass; this report is concerned with the latter cases. The incidence of paraplegia and the survival rate in this group were 0.9% and 91%, respectively. There were 89 men and 25 women in the series whose ages ranged from 22 to 87 years with an average age of 61. All types of aneurysms were represented; however, arteriosclerosis and dissection were the most common causes. The extent of aneurysm was variable, but most of the descending thoracic aorta was involved in more than half the cases. Associated diseases were present in 77% of cases. Operation consisted of aneurysmal replacement using inclusion technique with cardiac hemodynamics controlled by vasodilators and fluid replacement. During the past 4 years, proximal blood pressure has been controlled with nitroprusside. Cardiovascular hemodynamics, blood gases, electrolytes, and plasma osmolarity were monitored extensively and frequently to achieve the most desirable physiologic response to aortic clamping and operation. During this time 69 patients were treated. There were four (6%) deaths. None developed paraplegia or renal failure. Concomitant subclavian artery clamping was employed in 34 of these patients and in 22 additional patients with distal arch lesions. None in either group developed paraplegia. This indicated the safety of temporary subclavian artery occlusion. Death, both early and late, was due to a number of causes, but rupture of another aneurysm was the most common. This emphasizes the value of concomitant operation in patients with multiple aneurysms and careful follow-up in all patients.