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Acute increases in arterial blood pressure produced by occlusion of the abdominal aorta induces antinociception: peripheral and central substrates.

Occlusion of the abdominal aorta proximal to the renal arteries results in an increase in arterial blood pressure, inhibition of forepaw and hindpaw withdrawal to a noxious mechanical stimulus, and inhibition of the tail-flick reflex to noxious heat. Occlusion of the abdominal aorta distal to the renal arteries does not elevate arterial blood pressure and produces no antinociceptive effects. Occlusion of the vena cava lowers arterial blood pressure and produces no antinociception. The inhibitory effects of occlusion of the abdominal aorta depend upon activation of high pressure baroreceptors since bilateral sinoaortic denervation, but not bilateral vagotomy, eliminates the inhibition with respect to all behavioral measures. The inhibitory effects with respect to the tail-flick reflex also depend upon activation of a descending inhibitory system since reversible cold block of the spinal cord at the level of the second thoracic vertebra eliminates the antinociception. This antinociception is also eliminated following intrathecal administration of the noradrenergic receptor antagonist phentolamine, but not by intrathecal administration of either methysergide or naloxone. These data support the view that activation of high pressure baroreceptors by increases in arterial blood pressure produces antinociception via activation of a spinopetal noradrenergic system.

Animals↗

[A case of ruptured aneurysm of the thoraco-abdominal aorta associated with Behçet's disease].

A 41-year-old male with incomplete type of Behçet's disease was operated on because of ruptured aneurysm of the thoraco-abdominal aorta. A saccular pseudoaneurysm developed by rupture of the aortic wall involved the left postero-lateral portion of the supra-renal abdominal aorta. The defect in the aneurysm was closed using Dacron patch. The post-operative course was uneventful. However, seven months after discharge, the patient developed severe back pain at midnight, and was referred to our institution. On physical examination, a pulsatile mass was found in the right epigastric area. CT and DSA showed saccular pseudoaneurysm at the patch anastomotic site. Extra-anatomic long bypass grafting was performed from the ascending aorta to the infra-renal abdominal aorta. The abdominal aorta was occluded just below the diaphragm and the supra-renal portion of the aorta. Reconstruction of coeliac artery and superior mesenteric artery was made using branch grafts attached to the long graft. Surgical treatment of the complicated Behçet's disease should include extra-anatomic bypass, especially in the re-operative cases of ruptured aneurysm of the aorta.

Adult↗

Acute dissection originating in the abdominal aorta.

A primary abdominal aortic dissection was encountered in a 53-year-old hypertensive man who was admitted with a 2-week history of back pain. Treatment with an infrarenal aortic bifurcation graft complemented by reconstruction of the proximal aortic cuff was curative.

Aortic Dissection↗

[Thrombosis in the bifurcation of the abdominal aorta through the eyes of a neurologist].

We described a case of the malign course of the abdominal aorta bifurcation in a 75-year old woman with the case history of a successfully removed neurinom of the eleventh thoracic root on the left side. Despite a timely diagnosis with the recurrence of a spinal tumor being ruled out and followed by the streptokinase therapy, the course of the disease was lethal. Another six lethal cases of the thrombosis of the abdominal aorta studied retrospectively proved the necessity to improve both the diagnostics and the therapy of this disease. The possibilities of modern angiosurgery are, however, being put to very little use. In our opinion, it is better to use the term Lerich's syndrome to describe the chronic closure of the abdominal aorta bifurcation in men. In all other cases we recommend to use the descriptive term of the complete closure of the distal abdominal aorta. The complete thrombosis of the terminal abdominal aorta is not a very rare disease since it was found four times out of the total number of 4,746 dissections carried out in the period of five years (1986-1990). Reference is being made to the dissection materials of the 2nd Institute of Pathology and Anatomy of the 1st Medical Faculty of Charles University, Prague.

Aged↗

False aneurysm of the abdominal aorta due to blunt trauma.

Nonpenetrating trauma to the abdominal aorta is uncommon and the development of a traumatic abdominal aortic aneurysm is even more rare. The victims of blunt trauma to the abdomen should be examined for diminution or absence of femoral pulses, especially if numbness, diminished sensations, or motor weakness appear following trauma. If pulse abnormalities are present, aortography should be performed promptly to exclude aortic disruption or dissection. Immediate surgery should be performed once the diagnosis of aortic disruption is made. To our knowledge, this is the second reported case of successful surgical treatment of a false aneurysm of the abdominal aorta following nonpenetrating trauma.

Aorta, Abdominal↗

Age dependency of the biaxial biomechanical behavior of human abdominal aorta.

BACKGROUND: The biomechanical behavior of the human abdominal aorta has been studied with great interest primarily due to its propensity to develop such maladies as atherosclerotic occlusive disease, dissections, and aneurysms. The purpose of this study was to investigate the age-related biaxial biomechanical behavior of human infrarenal aortic tissue. METHODS OF APPROACH: A total of 18 samples (13 autopsy, 5 organ donor) were harvested from patients in each of three age groups: Group 1 (<30 years old, n=5), Group 2 (between 30 and 60 years old, n=7), and Group 3 (>60 years old, n=6). Each specimen was tested biaxially using a tension-controlled protocol which spanned a large portion of the strain plane. Response functions fit to experimental data were used as a tool to guide the appropriate choice of the strain energy function W. RESULTS: Under an equibiaxial tension of 120 N/m, the average peak stretch values in the circumferential direction for Groups 1, 2, and 3 were (mean +/-SD) 1.46 +/- 0.07, 1.15 +/- 0.07, and 1.11 +/- 0.06, respectively, while the peak stretch values in the longitudinal direction were 1.41 +/- 0.03, 1.19 +/- 0.11, and 1.10 +/- 0.04, respectively. There were no significant differences between the average longitudinal and circumferential peak stretch within each group (p > 0.1), but both of these values were significantly less (p < 0.001) for Groups 2 and 3 when compared to Group 1. Patients in Group 1 were modeled using a polynomial strain energy function W, while patients in Groups 2 and 3 were modeled using an exponential form of W, suggesting an age-dependent shift in the mechanical response of this tissue. CONCLUSION: The biaxial tensile testing results reported here are, to our knowledge, the first given for the human infrarenal aorta and reinforce the importance of determining the functional form of W from experimental data. Such information may be useful for the clinician or researcher in identifying key changes in the biomechanical response of abdominal aorta in the presence of an aneurysm.

Adult↗

Aortic dissection originating in the suprarenal abdominal aorta.

Spontaneous dissection of the abdominal aorta originating from the suprarenal aorta is very rare. Previous reports attest to the lethal nature of this disorder. This case represents the first report of successful repair of a spontaneous suprarenal abdominal aortic dissection by graft insertion with obliteration of both the entrance tear and the false lumen with reimplantation of the visceral vessels.

Aged↗

Inflammatory aneurysms of the abdominal aorta.

Inflammatory aneurysms of the abdominal aorta (IAAAs) have distinctive clinical and physical characteristics that separate them from typical atherosclerotic aneurysms. They were identified in 19 (7.2%) of 265 patients undergoing abdominal aortic aneurysm repair. Symptoms were present in 12 (63%) of 19, with one patient presenting with rupture, and multiple symptoms were present in six (32%). Intraoperatively, all aneurysms exhibited dense periaortic inflammation. Adjacent structures most frequently involved were the duodenum in 15 (79%) of 19 patients, the left renal vein in six (32%) of 19, and the ureter in five (26%) of 19. Seventeen (94%) of the 18 patients who underwent elective aneurysm resection survived. The involvement of retroperitoneal structures varied in number and severity, demonstrating that a wide spectrum of inflammation is present in IAAAs, making diagnosis and definition difficult.

Aged↗

Endoluminal repair of atypical dissecting aneurysm of descending thoracic aorta and fusiform aneurysm of the abdominal aorta.

A 62-year-old male patient was admitted with acute dissociation of the descending thoracic aorta and an infrarenal abdominal aortic aneurysm (AAA). Investigation revealed that the thoracic dissection probably had arisen retrogradely in the posterior wall of the AAA and extended superiorly to the left subclavian artery as a blind sac. Implantation of an endoluminal graft device below the renal arteries enabled simultaneous treatment of the AAA and the thoracic aortic dissection. The patient had an uncomplicated recovery. Postoperative aortography and computed tomography demonstrated normal flow through the aorta and endograft without leak of contrast into the AAA sac or the false lumen of the dissection. Contrast computed tomography 6 months after operation demonstrated that the false lumen was no longer evident.

Aortic Dissection↗

[Simultaneous revascularization of the renal arteries in conjunction with reconstruction of aneurysms of the abdominal aorta].

Simultaneous revascularization of stenosed renal arteries during resection of aneurysms of the abdominal aorta was performed in a consecutive series of 30 patients (mean age: 65 +/- 7 years; men 27 [90%]; women 3 [10%]). Right renal artery was operated upon in 20/30 cases (66%) and left renal artery in 15/30 cases (50%) for a mean degree of stenosis of 79 +/- 19%. Suprarenal extension of the aneurysm of the abdominal aorta was observed in 7/30 cases (23%). Emergency operation because of rupture of the aneurysm was necessary in 7/30 cases (23%). The following procedures were performed upon the renal arteries, either isolated or combined, in addition to resection of the aneurysm of the abdominal aorta: reimplantation of the renal artery in 15 cases, thrombendarteriectomy of the renal artery in 11 cases, patchangioplasty in 8 cases, bypass in 4 cases, dilatation in 1 case, autotransplantation in 1 case. The 30-day mortality was 1/23 (4%) for elective procedures versus 3/7 (43%) for emergency procedures (ruptures). Systolic (diastolic) blood pressure dropped from a preoperative mean value of 181 +/- 139 (104 +/- 18) mm Hg to a postoperative mean value of 147 +/- 18 (80 +/- 18) mm Hg: p less than 0.05 (p less than 0.05). Hence, simultaneous revascularization of stenosed renal arteries during resection of aneurysms of the abdominal aorta helps not only to salvage renal parenchyma but also to control the risk factor hypertonia in a significant number of patients.

Adult↗

Measurements of the diameter of the abdominal aorta using C.T.

The purpose of this study was to verify the difference between diameters of abdominal aorta obtained on corpses and on living bodies, using C.T. The Authors focused the attention on abdominal aorta, beneath kidney veins. Moreover, a linear relationship was found between height and diameter of abdominal aorta. A careful examination of the literature has shown discordance among the values of the abdominal aorta. The Authors conclude that improved techniques of radiological anatomy may offer an important support to obtain important data for clinical practice.

Adult↗

Ruptured aneurysms of the abdominal aorta.

The experience with ruptured aneurysms of the abdominal aorta is reported. Out of 395 aneurysms observed, 78 were ruptured. A review of case histories and an analysis of the causes of death demonstrate the importance of prompt diagnosis and early operation: delay and the use of complicated (TC) or invasive (angiography) instrumental examinations does not appear justified since clinical symptoms, plain standard abdominal films and ultrasound almost always lead to prompt diagnosis. Notwithstanding the improvements in resuscitation and intensive care procedures, a significant difference persists between the mortality rate of elective surgery (3 to 8%) and that of emergency surgery. There were 28 deaths (36%) for emergency surgery as against 3.4% for operations performed for non-ruptured aneurysms. This confirms the need for preventive treatment of aneurysmal lesions of the abdominal aorta, since even aneurysms smaller than 5 cm may rupture.

Aged↗

Follow-up of aortic dissection: contribution of MR angiography for evaluation of the abdominal aorta and its branches.

Spin-echo MR is an established method to evaluate thoracic aortic dissections, but is not well suited to study the abdominal aorta. In this study we evaluated whether MR angiography could provide a complete examination of the abdominal aorta. In 28 patients (40 MR studies) with suspected (n = 6) or known (n = 34) aortic dissection, MR studies were performed. Thoracic aorta was evaluated with spin-echo and gradient-recalled-echo MR imaging. Axial two-dimensional time-of-flight MR angiography with thin overlapping slices was used to study the abdominal aorta. Intermediate and high signal intensity on MR angiography was interpreted as patent flow, and low signal was interpreted as thrombus. The presence of an intima flap and the re-entry site could be depicted in all MR studies. Thrombus in the false channel was seen in 8 studies. The origin of the abdominal visceral branches and their relation to the false-true channel could be depicted, except in 4 of 80 renal arteries studied. Extension of the dissection into the coeliac trunk was seen in 2 and in the superior mesenteric artery in 10 studies. Dilatation of the suprarenal abdominal aorta was seen in 20 studies, and of the infrarenal aorta in 9 studies. MR angiography provides valuable information about the abdominal aorta and its branches in patients with aortic dissection. This makes MR imaging appealing as the preferred imaging modality for the diagnosis and follow-up of aortic dissection.

Aortic Dissection↗

Percutaneous transluminal angioplasty of the lower abdominal aorta.

Percutaneous transluminal angioplasty (PTA) of the lower abdominal aorta was performed in 14 patients aged 29-66 years (mean, 50). The disease was largely isolated to the distal aorta in this group. There were 13 women and 1 man; all were heavy smokers. Initial success, defined as improved or subsided clinical symptoms, improved ankle/arm indices, and improved angiogram, was achieved in all but one patient who thrombosed at the puncture site. At a mean follow-up period of 16 months (range, 1-58), a persistent beneficial effect was maintained in all patients. These results suggest that PTA is a safe alternative to surgery in patients with signs and symptoms of aortoiliac disease secondary to a significant but short stenotic segment of the lower abdominal aorta.

Adult↗

Sex difference in the mechanical properties of the abdominal aorta in human beings.

PURPOSE: A previous study has shown age- and sex-related differences in abdominal aortic compliance. In that study blood pressure determined by auscultation in the brachial artery was assumed to be equal to blood pressure in the abdominal aorta. To validate our findings we investigated the pressure-diameter (P-D) relationship of the abdominal aorta. METHODS: Diameter and pulsatile diameter change of the abdominal aorta were determined noninvasively by an ultrasound phase-locked echo-tracking system with simultaneous measurement of aortic pressure resulting in P-D curves in 27 healthy male and female volunteers 23 to 72 years of age. The degree of error in aortic compliance as calculated from blood pressure determined by auscultation of the brachial artery rather than from direct measurement of aortic pressure was evaluated. Compliance was defined as the inverse of pressure strain elastic modulus (Ep) or of stiffness (beta). RESULTS: There was no significant difference in the systolic pressure at the two sites, but the diastolic pressure was systematically overestimated by approximately 10 mm Hg when determined by the auscultatory method (p < 0.01) leading to a 15% to 20% underestimation of Ep and stiffness (beta). The individual P-D curves exhibited hysteresis, were nonlinear, and revealed that the aorta is more distensible at lower than at higher pressures. The steepness of the P-D curve decreased with increasing age and this occurred at an earlier age in men than in women. CONCLUSION: This investigation demonstrates a decrease in abdominal aortic wall distensibility with age, which occurs at an earlier age in men, and confirms earlier results by use of the indexes Ep and stiffness (beta). This implies that the abdominal aorta in men is more prone to degenerative changes, which may be one of the factors responsible for the sex difference in aortic vascular disease.

Adult↗

Surgical excision of sacral tumors assisted by occluding the abdominal aorta with a balloon dilation catheter: a report of 3 cases.

STUDY DESIGN: A report of 3 cases of upper sacral tumors excised by occluding the abdominal aorta with a balloon dilation catheter (BDC). OBJECTIVE: To investigate the feasibilities of reducing intraoperative hemorrhage and improving the safety of surgical excision of sacral tumors assisted by occluding the abdominal aorta with a BDC. SUMMARY OF BACKGROUND DATA: Surgical excision of upper sacral tumors has been considered a high-risk and difficult operation, with multiple complications because of its massive and uncontrollable intraoperative hemorrhage. However, until now and to our knowledge, no report on resection of sacral tumors assisted by occluding the abdominal aorta with a BDC is available. METHODS: A BDC was used to occlude the abdominal aorta for 40-65 minutes in assisting with resection of upper sacral tumors in 3 cases. RESULTS: After the abdominal aorta was occluded, much less intraoperative hemorrhage was found, and the volume of blood loss was only 100-200 mL. This procedure assisted the surgeon in identifying clearly the surgical margin and sacral nerves surrounded by the tumors. In addition, intraoperative contamination was also minimized. The blood pressure remained stable during the operation. CONCLUSION: To occlude the abdominal aorta with a BDC may effectively reduce intraoperative hemorrhage, thus assisting the surgeon in the complete and safe resection of upper sacral tumors.

Adult↗

Calcitonin gene-related peptide (CGRP) causes endothelium-dependent cyclic AMP, cyclic GMP and vasorelaxant responses in rat abdominal aorta.

Calcitonin gene-related peptide (CGRP), a neuropeptide found in nerves surrounding most blood vessels, is a potent hypotensive agent in both humans and rats. In isolated strips of rat thoracic aorta, CGRP has been reported to cause endothelium-dependent relaxation. To study the cellular and molecular mechanisms involved in CGRP-induced vasodilation, we investigated the roles of two second messengers, cyclic AMP and cyclic GMP, as potential mediators of the signal transduction mechanism leading to vasodilation in response to CGRP in rat aorta. In the present study, the abdominal aorta, rather than thoracic aorta, was used because of its higher content of endogenous CGRP and, therefore, the greater likelihood of regulation by CGRP in vivo. Each abdominal aortic ring was precontracted with norepinephrine (NE) at its EC50 concentration (10-20 nM). CGRP (3-300 nM) caused concentration-dependent relaxations (reducing the NE-induced contractions by 34%) that were completely dependent on endothelium. The relaxations in response to CGRP were correlated in a time- and concentration-dependent manner with increases in aortic levels of both cyclic AMP and cyclic GMP. CGRP (100 nM) caused significant elevations of cyclic AMP levels (1.4 to 3.2 pmol/mg protein, at 1 min) and cyclic GMP levels (1.6 to 3.6 pmol/mg protein, at 30 s). Like the vasorelaxant responses, both cyclic AMP and cyclic GMP responses to CGRP were totally dependent on the endothelium. Pre-incubation with indomethacin (3 microM, 15 min) did not alter cyclic AMP responses to CGRP (100 nM), suggesting that prostaglandins are not involved. Therefore, CGRP-induced vasodilations of abdominal aorta involve an endothelium-dependent mechanism associated with cyclic GMP elevations, similar to the mechanisms of vasodilation in response to acetylcholine and other endothelium-dependent vasodilators. However, CGRP-induced relaxations of aorta involve an additional mechanism (i.e., endothelium-dependent cyclic AMP elevations), which may also contribute to the intracellular mechanism of aortic vasodilation in response to CGRP.

1-Methyl-3-isobutylxanthine↗

Traumatic aneurysm of the abdominal aorta with acute thrombosis of bilateral iliac arteries.

A traumatic aneurysm of the abdominal aorta resulting in acute peripheral thrombosis is rare. A 29-year-old man suffered a sudden occlusion of the terminal abdominal aorta and bilateral iliac arteries. An infrarenal abdominal aortic aneurysm was found, along with destruction of lumbar vertebrae and an aberrant renal artery. The pathogenesis of this false aneurysm was thought to be traumatic rather than inflammatory because the patient's history and laboratory findings showed no signs of inflammatory reactions. He had been in an automobile accident five years previously, resulting in lumbar vertebral injury. Arterial reconstruction and intraoperative perfusion of the aberrant renal artery were performed successfully. To our knowledge, our case is the seventh one reported in the English literature of a traumatic aneurysm of the abdominal aorta successfully repaired by surgery.

Accidents, Traffic↗