Spinal cord ischemia after abdominal aortic operation: is it preventable?
(33/1622)
PURPOSE: Spinal cord ischemia after operation on the abdominal aorta is a rare event that is attributed to variations in the spinal cord blood supply. The purpose of this study was to evaluate the possible causes of this devastating event. METHODS: A survey of patients among the members of the Southern Association for Vascular Surgery was performed, and 18 patients were identified with spinal cord ischemia manifested by paraplegia or paraparesis after abdominal aortic operation. RESULTS: Preoperative computed tomographic, magnetic resonance, and aortographic results did not visualize the greater radicular artery (Adamkiewicz's artery) in any patient. Eleven patients underwent resection of infrarenal abdominal aortic aneurysms (AAAs): seven of these patients had tube grafts, three had aortobifemoral grafts, and one had an aortobiiliac graft. Five other patients underwent placement of aortobifemoral grafts, and one patient underwent aortobiiliac graft placement for occlusive disease. One patient underwent suprarenal AAA resection with an interposition graft to a previous aortobiiliac graft. The mean operative time was 3 hours and 39 minutes (range, 2 hours and 45 minutes to 6 hours and 30 minutes), with a mean aortic cross-clamp time of 48 minutes (range, 24 to 97 minutes). Sixteen aortic cross-clamps were placed infrarenally and two suprarenally (one in a case of ruptured AAA, the other a suprarenal AAA). Seventeen proximal anastomoses were end to end. The average minimum systolic blood pressure during the aortic cross-clamping was 96 mm Hg (range, 80 to 130 mm Hg). All the patients had internal iliac artery flow preserved with either prograde perfusion (10 patients) or retrograde perfusion (eight patients), and one patient underwent unilateral internal iliac artery ligation because of aneurysmal disease. One aortobifemoral-graft limb necessitated thrombectomy, but no cases of massive peripheral embolization occurred. When paraplegia was suspected after operation (6 to 20 hours after surgery), five patients underwent lumbar drainage. No clinical improvement was noted. CONCLUSION: Interference with pelvic blood supply from prolonged aortic cross clamping, intraoperative hypotension, aortic embolization, and interruption of internal iliac artery circulation have all been suggested as possible causes of spinal cord ischemia. In this survey, none of these factors proved to be significant as the sole cause of spinal cord ischemia. In the performance of an aortic operation with an end-to-end proximal anastomosis in the presence of severe external or internal iliac artery disease, there may be an increased incidence of spinal cord ischemia despite appropriate surgical techniques to ensure internal iliac perfusion. Spinal cord ischemia after abdominal aortic operations appears to be a tragically unpredictable, random, and unpreventable event. (+info)
Comparison between the transabdominal and retroperitoneal approaches for aortic reconstruction in patients at high risk.
(34/1622)
PURPOSE: The purpose of this study was to compare the transabdominal approach with the retroperitoneal approach for elective aortic reconstruction in the patient who is at high risk. METHODS: From January 1992 through January 1997, 148 patients underwent aortic operations: 92 of the patients were classified as American Society of Anesthesia (ASA) class IV. Forty-four operations on the patients of ASA class IV were performed with the transabdominal approach (25 for abdominal aortic aneurysms and 19 for aortoiliac occlusive disease), and 48 operations were performed with the retroperitoneal approach (27 for abdominal aortic aneurysms and 21 for aortoiliac occlusive disease). There were no significant differences between the groups for comorbid risk factors or perioperative care. RESULTS: Among the patients of ASA class IV, eight (8.7%) died after operation (retroperitoneal, 3 [6.26%]; transabdominal, 5 [11.3%]; P =.5). There was no difference between groups in the number of pulmonary complications (retroperitoneal, 23 [47.9%]; transabdominal, 19 [43.2%]; P =.7) or in the development of incisional hernias (retroperitoneal, 6 [12.5%]; transabdominal, 5 [11.3%]; P =.5). The retroperitoneal approach was associated with a significant reduction in cardiac complications (retroperitoneal, 6 [12.5%]; transabdominal, 10 [22.7%]; P =.004) and in gastrointestinal complications (retroperitoneal, 5 [8.3%]; transabdominal, 15 [34.1%]). Operative time was significantly longer in the retroperitoneal group (retroperitoneal, 3.35 hours; transabdominal, 2.98 hours; P =.006), as was blood loss (retroperitoneal, 803 mL; transabdominal, 647 mL; P =.012). The patients in the retroperitoneal group required less intravenous narcotics (retroperitoneal, 36.6 +/- 21 mg; transabdominal, 49.5 +/- 28.5 mg; P =.004) and less epidural analgesics (retroperitoneal, 39.5 +/- 6.4 mg; transabdominal, 56.6 +/- 9.5 mg; P =.004). Hospital length of stay (retroperitoneal, 7.2 +/- 1.6 days; transabdominal, 12.8 +/- 2.3 days; P =.024) and hospital charges (retroperitoneal, $35,587 +/- $980; transabdominal, $54,832 +/- $1105; P =.04) were significantly lower in the retroperitoneal group. The survival rates at the 40-month follow-up period were similar between the groups (retroperitoneal, 81.3%; transabdominal, 78.7%; P =.53). CONCLUSION: In this subset of patients who were at high risk for aortic reconstruction, the postoperative complications were common. However, the number of complications was significantly lower in the retroperitoneal group. Aortic reconstruction in patients of ASA class IV appears to be more safely and economically performed with the retroperitoneal approach. (+info)
Coronary and aortic calcification among women 8 years after menopause and their premenopausal risk factors : the healthy women study.
(35/1622)
In the Healthy Women Study, the relationship between cardiovascular risk factors measured premenopausally at age 48, use of hormone therapy, and coronary and aortic calcification at age 58 were evaluated among 169 women. Approximately 63% of women had no coronary calcification, but only 29% had no aortic calcification. Coronary calcification and aortic calcification were positively correlated with each other. There was a very strong association between low density lipoprotein cholesterol (LDL-C) level and coronary calcification. Among women with premenopausal levels of LDL-C <100 mg/dL, only 9% had a coronary calcium score >/=101 compared with 30% of women with an LDL-C >160 mg/dL. Only 5% of women with a high density lipoprotein cholesterol (HDL-C) level >60 mg/dL had high coronary scores. The level of HDL(2)-C was especially strongly inversely related to coronary calcium scores. Cigarette smoking was a very important determinant of both high aortic and high coronary calcium scores. Other risk factors associated with greater coronary calcium were higher systolic blood pressure, triglycerides levels, and blood glucose. Use of hormone replacement therapy was associated with less coronary calcium (NS). For both hormone replacement therapy users and nonusers, the levels of LDL-C and HDL-C measured premenopausally were predictors of coronary and aortic calcium scores. Thus, risk factors evaluated premenopausally are powerful predictors of coronary and aortic calcification, a marker of atherosclerosis, measured 8 years after menopause, 11 years later in these women. (+info)
Differential suppression of pressure-overload cardiac and aortic hypertrophy in rats by angiotensin-converting enzyme inhibitors.
(36/1622)
Role of tissue angiotensin-converting enzyme (ACE) in the development of pressure-overload cardiovascular hypertrophy was examined in rats by comparing the inhibitory effect of trandolapril (high efficiency on tissue ACE) with that of enalapril (low efficiency) at equally antihypertensive doses. Rats with abdominal aorta banded or sham-operated were orally treated with trandolapril (0.5 mg/kg per day), enalapril (20 mg/kg per day) or vehicle for 8 weeks after the surgical maneuvers. In vehicle-treated rats, the banding raised the intra-aortic systolic pressure by 58%, diastolic pressure by 31%, maximum velocity of pressure rise by 65%, left ventricular (LV) weight by 41%, LV hydroxyproline concentration by 56%, aortic mass by 46%, LV ACE activity by 45%, and aortic ACE activity by 265%. Although both drugs equally reduced the aortic systolic pressure to approx. 70% and diastolic pressure to approx. 80% that of banded rats receiving vehicle, trandolapril partially prevented the LV hypertrophy, whereas enalapril yielded nonsignificant suppression. Trandolapril completely prevented the LV increments in hydroxyproline and ACE activity, whereas enalapril partially inhibited the LV hydroxyproline increase with little inhibition of LV ACE activity. In contrast, both inhibitors almost completely prevented the aortic hypertrophy, with the ACE activity of the aorta being potently inhibited. These results suggest that tissue ACE is the principal factor for pressure-induced aortic hypertrophy and an important yet non-essential factor for LV hypertrophy. (+info)
Aspirin inhibits development of coronary atherosclerosis in cynomolgus monkeys (Macaca fascicularis) fed an atherogenic diet.
(37/1622)
The effect of aspirin in the primary prevention of diet-induced atherogenesis in cynomolgus monkeys was studied. The diet consisted of 2% cholesterol and 10% butter by weight for 24 wk. Six monkeys received only the atherogenic diet and five monkeys received the diet plus aspirin, 81 mg/monkey per day. Aspirin did not affect plasma cholesterol levels or aortic atherosclerosis. Platelet aggregation to arachidonic acid was almost completely suppressed. Aspirin decreased significantly the number of coronary vessels with atherosclerotic involvement, and the number of coronary vessels narrowed by 20% or more. Thus, aspirin appears to exert a protective effect in the primary prevention of diet-induced coronary atherosclerosis in a primate model. (+info)
The use of endovascular stents in the treatment of penetrating ulcers of the thoracic aorta.
(38/1622)
Penetrating atheromatous ulcers of the aorta are increasingly recognized as a distinct entity. Although their natural history remains ill-defined, such ulcers may lead to pseudoaneurysmal formation, dissection, rupture, or embolization. Given the morbidity associated with open repair, endovascular repair of penetrating atheromatous ulcers may be the treatment of choice. Although stent-graft replacement of acute aortic dissections has recently been described, endovascular repair of penetrating thoracic aortic ulcers has not previously been reported. We report two cases of successful endovascular repair of penetrating atheromatous ulcers that previously ruptured. (+info)
Distribution of early atherosclerotic lesions in the human abdominal aorta correlates with wall shear stresses measured in vivo.
(39/1622)
OBJECTIVES: to study the relationship between wall shear stresses measured in vivo and early atherosclerotic lesions in the abdominal aorta. MATERIALS: eight young volunteers for in vivo wall shear-stress measurements. Abdominal aortas from 10 young adults without signs or history of atherosclerotic disease were obtained by autopsy for histomorphometric measurements. METHODS: wall shear stresses were measured in the abdominal aorta above and below the renal arteries using a magnetic resonance technique with high resolution for imaging and blood velocity mapping. At identical abdominal aortic locations, intimal thickness was measured blindly using histomorphometric techniques and correlated to wall shear-stress variables using linear-regression analysis. RESULTS: intimal thickness showed a linear decrease with mean wall shear stress (r=-0.90, p<0.01) and with maximum wall shear stress (r=-0.86, p<0.01). CONCLUSIONS: intimal thickness in the normal abdominal aorta is associated with mean, maximum and oscillating wall shear stresses. These in vivo data corroborate previous in vitro studies suggesting that low and oscillating wall shear stresses are localising factors for intimal thickening and hence the early development of atherosclerosis. (+info)
Chlamydia pneumoniae DNA detection in peripheral blood mononuclear cells is predictive of vascular infection.
(40/1622)
Abdominal aortic aneurysm tissue and peripheral blood mononuclear cells (PBMC) of 41 consecutive subjects undergoing abdominal aortic aneurysm surgery were analyzed by polymerase chain reaction (PCR) for the presence of Chlamydia pneumoniae, Mycoplasma pneumoniae, and Helicobacter pylori DNA. Twenty patients (49%) were positive for C. pneumoniae DNA-16 (39%) in both PBMC and aneurysm tissue, 3 (7.3%) in PBMC only, and 1 (2.4%) in the artery specimen only. Previous exposure to C. pneumoniae was confirmed in 19 (95%) of the 20 PCR positive subjects by C. pneumoniae-specific serology, using the microimmunofluorescence test. None was positive for H. pylori or M. pneumoniae DNA, either in the PBMC or in the artery specimens. In conclusion, carriage of C. pneumoniae DNA is common both in PBMC and in abdominal aortic tissue from patients undergoing abdominal aneurysm surgery. Blood PCR may be a useful tool for identifying subjects carrying C. pneumoniae in the vascular wall. (+info)