Search

Although acute aortic occlusion (AAO) and acute mesenteric ischemia (AMI) are relatively rare condition, it is very important to know clinical features and managements for these because a delay in diagnosis and appropriate interventions results in high morbidity and mortality. AAO can result from aortic saddle embolus, acute thrombosis of an atherosclerotic aorta, and so on. Superior mesenteric artery embolism and thrombosis are main cause of AMI. The purpose of this article is to review the pathophysiology, clinical presentation, diagnosis, and management of these diseases. The latest information in this article may help readers to promptly make the diagnosis and effectively manage it in a timely manner.

Cardiomyopathy is a major life-threatening complication in Duchenne muscular dystrophy (DMD). Cardiac output is always low in advanced stage patients. Impaired muscles presumably require extremely low circulation, while blood flow to brain and internal organs is probably maintained. Therefore, the redistribution of systemic circulation must be another important factor which determines whether or not the cardiomyopathy results in fatal heart failure. Although great efforts have been focused on the cardiac function, this problem has seldom attracted attentions. Assuming that diameter of blood vessels reflects blood flow, we measured the diameter of abdominal aorta on CT at four levels: 1) beginning of the abdominal aorta, 2) before and 3) after the branching of renal arteries, 4) before bifurcation of the common iliac arteries. Six bed-ridden DMD patients were compared with 10 ambulant patients suffering from other neurological and non-neurological diseases. We obtained following results. First, the diameter of abdominal aorta is significantly smaller in DMD patients. Second, the decrement is most prominent between before and after the branching of the renal arteries. These results clearly showed predilection of renointestinal circulation at the sacrifice of lower extremities. This narrowing of distal aorta was also observed in Kugelberg-Welander disease and understood as a sequelae of longstanding abolition of lower extremity functions.

Composite grafts have a tendency to develop intimal hyperplasia (IH) at the anastomosis between the different graft materials. The author developed a new prosthesis, modified composite graft (MCG) to control this problem. Experimental study: MCG consists of proximal 3cm of Dardik Biograft and a distal 3cm of autogenous vein (AV). Proximal segment of AV, which is anastomosed to the Biograft, was treated with 1% glutaraldehyde during operation. Then MCG was implanted in the canine infrarenal abdominal aorta. The anastomosis between Biograft and AV was wrapped with a strip of Biograft to prevent the invasion from the surrounding tissue that may also cause IH. The patency rate at 33 months was 75% (9/12). No IH was observed at Biograft-AV anastomosis. Clinical study: Thirty MCG's were implanted in patients with chronic obstructive arterial disease. None of the patients had enough autogenous vein for a complete graft. Cumulative patency rates were 67.3% at 1 year and 31.6% at 5 years. Over-all limb salvage rate was 75%. All graft failure was caused by IH at the site of proximal anastomosis between the femoral artery and Biograft or graft thrombosis probably due to low blood flow. In conclusion, IH was successfully prevented at the site of Biograft-AV anastomosis in MCG.

The important two-dimensional echocardiographic finding of dissecting aneurysm in the acute stage is characterized by the presence of an oscillating intimal flap which is thought to be of highly diagnostic value. This report describes about three cases with dissecting aneurysm in which an oscillating flap was transiently observed. In Case 1 (62-year-old female), an oscillating flap observed in the aortic arch seven hours after the onset was not detected three days later. A flap in Case 2 (65-year-old male) which had been present in the descending aorta three hours after the onset of illness disappeared two days later. In Case 3 (55-year-old male), only an intimal flap without fine oscillation was demonstrated in the abdominal aorta by echocardiography performed three days after the onset of illness. In the acute phase of dissection, the echocardiographic detection of an oscillating flap seems to depend on the time of the study after the attack.

In order to investigate the function of the circulatory system in SART rats, systolic blood pressure and regional arterial blood flow were examined. It was found in SART stressed rats that the blood pressure was about 10 mmHg lower than that of the non-stressed group on the 6th day of stressing and after stressing, and such low blood pressure was maintained for several days. SART rats showed a decrease in the average blood flow value in the common carotid artery, increases in the average and instantaneous maximum blood flow values in the superior mesenteric artery, and the instantaneous maximum blood flow value in the abdominal aorta had a tendency to increase, though little changes were observed in the renal and the femoral arteries. It was suggested by flow contours that there was hardening in the vessel walls of the common carotid artery and the abdominal aorta, and softening in the superior mesenteric artery. SART stress-induced hypotension was further decreased by a single dose of guanethidine, clonidine, or hydralazine, but not by neurotropin. Continuous preadministration of neurotropin prevented the SART stress-induced hypotension and changes in blood flow. From the above mentioned results, the sympathetic nerve may be thought to be decreased in tension, or be depressed, in the circulatory system of SART rats.