[Clinical investigation on the adjunctive method in the surgery of thoracic aortic aneurysms--comparison of the temporary bypass and partial extracorporeal bypass].

Since 1980, two different operative strategies were employed during resection to provide distal aortic perfusion by temporary bypass (Group "TB", 39 patients) or partial extracorporeal bypass (Group "PEC", 39 patients) in the operation for the thoracic descending aortic aneurysms or the dissecting aortic aneurysms with DeBakey type III. No significant differences were found in the patient population or the operative procedures between two groups. Mean bypass flow in Group "PEC" was 1850 +/- 70 (ml/min), which is significantly higher than in Group "TB" (1000 +/- 240 ml/min). However, there were no significant differences in the distal aortic pressure between two groups, which was due to administration of vasodilators. Platelet counts in Group "PEC" were significantly lower in the postoperative courses, probably caused by the use of roller pumps or suckers. The incidence of the postoperative renal dysfunction was almost the same in two groups. Cardiac functions during temporary bypass were suppressed by the aortic cross-clamping, therefore, it is necessary to evaluate the cardiac function preoperatively in employing this method. Partial extracorporeal bypass has the disadvantages of the requirement for full heparinization, but it can be indicated to almost all cases, even to the patients with poor cardiac function. It also has the advantage to maintain the distal perfusion in the unexpected intraoperative situations. The method of distal aortic perfusion should be determined by patient-related and disease-related factors.