Three cases of aortic dissection involving abdominal aortic aneurysms are reported. Two of the 3 cases died from intestinal necrosis. In one of them, the abdominal aortic aneurysm ruptured following aortic dissection. Fenestration was not performed at the proximal anastomosis in the operation, and it is thought that this resulted in occurrence of intestinal necrosis due to superior mesenteric artery obstruction. In the other non-survivor, aortic fenestration and graft replacement were performed. However, he died from descending-sigmoid colon necrosis due to internal iliac artery obstruction. An autopsy demonstrated no problem that with the graft anastomosis. The successful case of aortic fenestration and graft replacement had no postoperative complications. Since the aortic wall is fragile in acute aortic dissection, it is advisable that operation be conducted 1 month after the onset except in cases of aortic rupture and malperfusion syndrome. Fenestration, which is usually safe in chronic dissection, should be performed and it is desirable to fenestrate the aortic wall if possible even in acute dissection.

For the purpose of reducing blood loss and blood transfusion, 100 cases of acute aortic dissection treated at this department were studied, focusing on surgery for aortic dissection and coagulation factors, fibrinogen in particular. In cases of aortic dissection, fibrinogen decreased at the acute stage, and showed concentrations significantly lower in Stanford Type A than in Stanford Type B, in extensive dissection (DeBakey Type I or Type III retrograde dissection) than in limited dissection (DeBakey Type II), and in open false lumen type than in closed false lumen type. In the assessment of 34 cases of acute Stanford Type A aortic dissection operated on within 24h of onset, it was found that a marked prolongation of activated clotting time (ACT≥1, 000s) during cardiopulmonary bypass causes an increase in blood transfusion. When ACT was maintained for 400s or longer, to inhibit the marked prolongation of ACT, by changing at any time the dose of heparin during cardiopulmonary bypass by 50-250units/kg on the basis of the preoperative fibrinogen level, instead of fixing it at 300units/kg, ACT decreased significantly, and was controlled at appropriate levels despite the low concentration of fibrinogen. As fibrinogen can be measured in the hospital, and the result obtained in a short time, it is considered to play an important role in controlling ACT to determine the dose of heparin based on its concentration.

From January 1, 1999 through December 31, 2001, 152 cases of aortic dissection (77 cases of Stanford Type A and 75 Type B) were treated in our department. Among those cases, 25 patients (10 Type A (13.0%) and 15 Type B (20.0%)) were accompanied by atherosclerotic aneurysm. The mean age of onset of those cases was 71.4±9.8 years. Because those patients were older, it is necessary to pay attention to decide on treatment strategy and surgical procedure. In order to prevent atherosclerotic plaque being pumped into the brain vessel, we devised the following surgical procedure and perfusion method of cardiopulmonary bypass as follows; 1. In cases of retrograde perfusion from the femoral artery through the aneurysm, we usually pump the blood more slowly and gently than the antegrade perfusion. 2. We reduce the perfusion pressure after the heart beat changes to ventricular fibrillation. 3. After distal anastomosis of the vascular prosthesis, the blood is pumped from its perfusion branch. An initial tear was located in the spindle-shaped aneurysm in 3 cases (2.0%). Of 11 cases that aortic dissection was in contact with the atherosclerotic aneurysm, 2 cases of saccular shaped aneurysm terminated the dissection. In the 9 cases of spindle shaped aneurysm, however, the dissection involved the aneurysm, suggesting that the effect of aneurysm on the dissection depended on the aneurysmal shape. When the dissection coexists with aneurysm in different portions of the aorta, re-dissection may extend into the aneurysm. Therefore, careful decision making on the timing of surgery is necessary for abdominal aortic aneurysm complicated with aortic dissection, even when treating conservatively.

Patients with Stanford A acute aortic dissection who were treated within 48h of onset in our institution between January 1, 1999 to December 31, 2001 were divided into those younger than 70 years and those 70 years or older to compare the results of surgical and conservative therapies and the cause of death. The total number of patients was 74, the age was 33 to 88 years (66.5±11.9 years), and the ratio of men to women was 39:35. Atherosclerotic aortic aneurysm was concurrently observed in 21.1% in those 70 years or older, which was significantly higher than 5.6% in those younger than 70 years. Of 36 patients younger than 70 years, 27 (75.0%) were saved, compared with 18 of 38 patients (47.4%) 70 years or older. Surgical therapy was performed on 46 patients, 62.2%. The percentage of patients who underwent surgery was 69.4% in those younger than 70 years and 55.3% in those 70 years or older with no significant differences. Operative death occurred in 9 of 21 patients (42.9%) 70 years or older, which was significantly higher than the 12.0% (3 of 25) in those younger than 70 years. For 28 patients who did not receive surgical treatment, death occurred in 6 of 11 patients (54.5%) younger than 70 years compared with 10 of 17 (58.8%) 70 years or older with no significant difference: both rates were higher than 50% and 9 patients died of rupture during operative preparation. Since elderly people have a high risk for various complications and have poor operative results, it is important to carefully determine the therapeutic strategy, select a simple operative technique and conduct the operation as soon as possible.