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Immediate postgadolinium spoiled gradient-echo MRI for evaluating the abdominal aorta in the setting of abdominal MR examination.

To assess the reproducibility and image quality of immediate postgadolinium chelate spoiled gradient-echo MRI in demonstrating disease of the abdominal aorta. All patients (27 patients: 21 men, 6 women) with substantial disease of the abdominal aorta, who underwent abdominal MR examinations at 1.5 T between 1991 and 1995, were entered in the study. Patients were referred for evaluation of suspected aortic disease (14 patients) or other abdominal diseases (13 patients). Three experienced investigators manually measured luminal and external aortic wall diameters and rated image quality, definition of inner and outer walls, extent of disease, and presence of other abdominal abnormalities, in an independent fashion. A cardiovascular surgeon then rated all studies to determine whether clinical management could be based on the MR findings alone. There was 98 to 99% agreement in measurements of luminal and external wall diameter between the three investigators. Overall image quality was rated as good in 77.8 to 88.9% of patients. A total of 31 additional nonaortic abdominal abnormalities were detected by all observers. The cardiovascular surgeon rated 25 of 27 studies as adequate to determine clinical management based on MR findings alone. Immediate postgadolinium spoiled gradient-echo MRI is a reproducible technique for the demonstration of abdominal aortic disease and possesses good image quality. Advantages of this technique include simultaneous evaluation of other nonvascular diseases of the abdomen, short examination time, and easy implementation as part of routine abdominal MRI scanning protocol.

Aged↗

Medial elastin in the thoracic and abdominal aorta of sheep and lambs.

Aortas were removed from six mature lambs and four sheep and pressure fixed at 100 and 120 mmHg pressure (1 mmHg = 133.322 Pa), respectively, in 10% buffered formalin. The numbers of elastin layers were counted from cross sections at different distances down the aorta, from the distal arch to the iliac bifurcation, and showed a linear decrease in the thoracic aorta. In the abdominal aorta there was no difference in values from the diaphragm to the aortoiliac bifurcation in the lamb, but a slight decrease in the sheep. If y = mx + b, where y is the number of medial lamellar units (MLU), b the intercept, x the distance from the last brachiocephalic branch in centimetres, and m the slope, we obtained the following equations (with standard deviations): lamb thoracic aorta; y = -6.29 (+/- 0.71)x + 106 (+/- 12); sheep thoracic aorta; y = -3.46 (+/- 0.40)x + 140 (+/- 21.4); lamb abdominal aorta; y = 0.51 (+/- 1.48)x + 37 (+/- 7.7); sheep abdominal aorta; y = -0.85 (+/- 0.28)x + 66 (+/- 5.9). Tension per lamellar unit was calculated and plotted versus distance yielding a linear increase in the entire lamb aorta but an abrupt increase between thoracic and abdominal aortas in the sheep. This causes the pulse wave to move uniformly with increasing speed along the length of the lamb aorta but would cause an abrupt change in the wave at or about the diaphragm in the sheep. Distortions in the pulse wave could produce local stress concentrations in the abdominal aorta which might render it more susceptible to atherosclerosis than the thoracic aorta.

Animals↗

Spontaneous retrograde dissection of the entire thoracic aorta originating in the abdominal aorta. Case report and review of the literature.

Spontaneous retrograde thoracic extension of the abdominal aortic dissection is extremely rare and difficult to manage. Only five cases have been previously reported in the English literature (dissection reaching the ascending aorta in four, dissection limited in the descending thoracic aorta in one), and all the cases of dissection which reached the ascending aorta were lethal. We herein report one case of a 37-year-old man who was operated on for spontaneous retrograde dissection of the entire thoracic aorta originating in the suprarenal abdominal aorta. Preoperative aortogram revealed the site of the intimal tear just above the celiac artery. He urgently underwent graft replacement of the descending thoracic aorta and the abdominal aorta with reimplantation of the thoracoabdominal visceral arteries. Although the patient had to undergo the second operation for the dissection of the remaining thoracic aorta four months postoperatively, he has been doing well 18 months after the second operation.

Adult↗

[Atherosclerotic aneurysms of the abdominal aorta].

Aneurysm of abdominal aorta was found in 58 cases (0.87 per cent) of a group of 6646 postmortems. The group comprised persons over 15, 45 males and 13 females. The highest frequency of aneurysms (36) was at the age 71 to 80. Rupture of the aneurysm occurred in 15 cases and vascular diseases represented a half part of other causes of death. All the aneurysms were atherosclerotic, in one case a combination with mucold dystrophy was found. Evidence of arterial hypertension was in 43 per cent of the analyzed cases. Histology was performed in 24 cases and proved a destruction of elastic structures in tunica media, fibrosis, loss of smooth muscle cells followed by substantial thinning of the vessel wall. Widening of adventicia was caused by increase of collagen fibres. Discussion concerned formal pathogenesis of the lesion.

Aged↗

Stenting of stenosis of the abdominal aorta.

Isolated abdominal aortic stenosis resulting in bilateral lower limb claudication is uncommon in Asians. We report a 75-year-old Oriental man with isolated abdominal aortic stenosis who underwent intraluminal stenting, resulting in the abolishment of a 76 mmHg gradient. As the stenotic segment was local, only the mid-segment of the Palmaz stent was apposed to the aortic wall. Follow-up ultrasound scans showed that the partially apposed stent was potent, with no thrombosis in the free space between the stent and the wall. Hence, although aortic stenting in this patient resulted in partial apposition of the stent to the aortic wall, there was no thrombosis or migration of the stent. The patient remained symptom-free one year post-stenting. Stenting in this patient with failed balloon angioplasty was a safe and efficacious method of treating significant isolated abdominal aortic stenosis.

Aged↗

Spontaneous dissection of the abdominal aorta.

Spontaneous abdominal aortic dissection is a rare entity, often with a clinically unspecific presentation. The cause of the dissection is unclear. Angiography used to be the definitive diagnostic study, but today a correct diagnosis can be achieved with CT scanning and magnetic resonance angiography. The optimal form of management for the individual patient is not clearly established. Chronic dissections may best be managed conservatively, with close follow-up achieved with CT scanning and magnetic resonance. Acute and complicated dissections should be treated surgically with aortic and aortic branch replacement if it can be offered with low morbidity and mortality. In selected cases, resection of the ischemic organs may represent an alternative.

Acute Disease↗

True juxta-anastomotic aneurysms in the residual infra-renal abdominal aorta.

INTRODUCTION: abdominal aortic dilatation can occur above the graft following repair of infra-renal abdominal aortic aneurysm (AAA). This study aimed to determine the incidence and possible aetiological associations of recurrent juxta-anastomotic aneurysms following open repair of AAA. METHODS: the diameter of the infra-renal aorta above the graft of 135 patients who had previously undergone open AAA repair was determined using ultrasound. In those where the diameter was greater than 40 mm a CT scan was undertaken. Co-morbid and operative details were determined from the patients and their clinical notes. RESULTS: seven patients had true juxta-anastomotic aneurysms (>40 mm) in the residual infra-renal abdominal aorta, the occurrence of which was associated with tobacco smoking and hypertension. There was no association with other co-morbid factors, surgical operative details or the development of iliac aneurysms (which occurred in 3% of patients). CONCLUSIONS: true juxta-anastomotic aneurysms develop in the residual infra-renal neck of patients following open repair of abdominal aortic aneurysm. Tobacco smoking and hypertension are significant factors associated with the development of these aneurysms. This group of patients may warrant surveillance to prevent aneurysm rupture.

Aged↗

Comparison of longitudinal elastic properties of proximal and distal strips of aorta-branch junctions from the abdominal aorta of sheep.

Narrow longitudinal continuous strips were cut from the abdominal aorta and its major branches so that each strip contained the same width of aorta, bifurcation, and branch although the lengths of the three segments were different. A grid was marked on each region, and photographs made at a variety of strains as the whole strip was stretched at a strain rate of 2 cm/min with an Instron tensile testing machine. Measurements from the grids gave the strains for each region, and stress-strain curves were calculated. The proximal bifurcation zone was much more extensible than any of the other regions, owing mainly to changes in the "slack" of the collagen fibers (p less than 0.01). This would imply that the shape and cross-sectional area of the bifurcation region are apt to change between diastole and systole, and implies that model studies which assume the shape of the bifurcation region is constant may not be accurate.

Animals↗

Tandem coarctation of the thoracic aorta with hypoplasia of the abdominal aorta.

After resection of the coarctation in a 3-year-old child with end-to-end anastomosis, a second membrane was found 1.5 cm lower. After a successful reoperation with an aortoplasty using Gore-Tex weak femoral pulses persisted. At catheterization, an area of irregular narrowing of the abdominal aorta just distal to the superior mesenteric artery was found with hypoplasia of the iliac and femoral arteries. In addition, this child had a two-sided cheilo-gnatho-palatoschisis, vesicoureteral reflux and absence of gall bladder and hepato-duodenal ligament. It is worthwhile considering that a second or third aortic abnormality can be hidden by a coarctation of the aorta.

Aorta, Abdominal↗