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T C Bower

Publications and source records attributed to T C Bower.

69 records · Page 4Linked to original sources
PubMed1992

Ruptured abdominal aortic aneurysms: repair should not be denied.

The records of 231 patients (189 men, 42 women) treated during the last decade for ruptured infrarenal abdominal aortic aneurysm were reviewed to evaluate complications and mortality rates and to determine if preoperative factors would preclude attempt at surgical repair. Mean age was 73.7 years (range, 50 to 95 years). Fifty-seven patients (24.7%) were greater than or equal to 80 years of age. Sixty-eight patients (29.4%) had known abdominal aortic aneurysm before rupture. Preoperative systolic blood pressure was less than or equal to 90 mm Hg in 155 patients (67.1%). Fifty-six patients (24.2%) had cardiac arrest before operation. The overall mortality rate from admission until the end of the hospital stay was 49.4% (114 of 231). Seventeen patients (7.4%) died in the emergency department, 40 (17.3%) in the operating room, 27 (11.7%) during the first 48 postoperative hours, and 30 (13.0%) died later but during the same hospitalization. The 30-day operative mortality rate was 41.6%. Mean age of those who died was higher (75.3 years) than of those who survived (72.2 years) (p less than 0.02). Of patients greater than or equal to 80 years, 43.9% survived. Survival was lower among women (35.7%) than men (54.0%; p less than 0.04). A high APACHE II score, a low initial hematocrit, preoperative hypotension, and chronic obstructive pulmonary disease were associated multivariately with increased mortality rates (p less than 0.02). However, 59 of the 155 patients (38.1%) with preoperative hypotension survived. Deaths were high (80.4%) among patients with cardiac arrest (45 of 56); still, 28.2% of patients (11 of 39) survived repair after cardiac arrest.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1991

Brachiocephalic aneurysm: the case for early recognition and repair.

Over a 40 year period (1950-1990) only 73 patients were treated surgically for brachiocephalic aneurysms. An operation was performed for 38 subclavian, 25 extracranial carotid, six innominate, three aberrant right subclavian, and one vertebral artery aneurysm. Twenty-three other associated aneurysms occurred in 14 patients. Five patients had an additional untreated brachiocephalic aneurysm, and nine patients had 18 aneurysms located in different anatomic regions. There were 40 men and 33 women with a mean age of 50.5 years (range 16 to 82 years). Forty patients (54.8%) presented with potentially life- or limb-threatening signs or symptoms, including stroke or transient ischemic attacks (31.5%), upper extremity ischemia (19.2%), and rupture (4.1%). Atherosclerosis was most common in innominate aneurysms (66.7%) but also occurred in subclavian (34.1%) and carotid aneurysms (12.0%). Thoracic outlet compression was a common etiology for subclavian aneurysms while trauma or spontaneous dissection was more frequent for carotid aneurysms. Six deaths (8.2%) occurred within 30 days of operation: two from rupture, three in association with concomitant cardiovascular operations, and one from emergency carotid ligation. There were no deaths with elective isolated surgical repair. Overall five and 10 year survival in patients with brachiocephalic aneurysms was 80.8% and 61.4%, respectively. The majority of brachiocephalic aneurysms present with life- or limb-threatening complications and are associated with a high mortality for emergency or concomitant repair. Early elective isolated surgical repair remains the optimal therapy.

Aneurysm↗
PubMed1991

Ischemic injury to the spinal cord or lumbosacral plexus after aorto-iliac reconstruction.

Between January 1, 1980, and June 30, 1989, 9 patients (6 males and 3 females) developed ischemic injury to the spinal cord or lumbosacral plexus following 3,320 operations on the abdominal aorta (0.3%). The incidence of this complication was 0.1% (2 of 1,901) after elective and 1.4% (3 of 210) after emergency abdominal aortic aneurysm repair, and 0.3% (4 of 1,209) after repair for occlusive disease. Three of the latter had prior clinical evidence of distal embolization. Eight grafts were bifurcated (aorto-iliac:four, aorto-femoral: three, aorto-ilio-femoral:one). One patient underwent extra-anatomic revascularization. Only two patients had supraceliac aortic cross-clamping and one patient underwent exclusion of both internal iliac arteries. Four patients had hypotension. Early mortality was 22% (two of nine). Severe perioperative complications, mostly due to associated visceral and somatic ischemia and sepsis, were present in seven of the nine patients. The extent and type of the neurologic injury correlated with long-term outcome. Patients with ischemic injury of the lumbosacral roots or plexus had better recovery. Attention to the pelvic circulation and the collateral blood supply is important. Use of gentle technique to prevent embolization, avoidance of hypotension and prolonged supraceliac cross-clamping, revascularization of at least one internal iliac artery, and the use of heparin may decrease but not eliminate paraplegia. Once this unexpected complication occurs, careful neurologic evaluation should be done to localize the lesion and aid prognosis.

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PubMed1991

Stump pressure, the contralateral carotid artery, and electroencephalographic changes.

Electroencephalographic (EEG) monitoring and measurement of stump pressure are the most widely employed methods of assessing the risk of cerebral ischemia during carotid endarterectomy. The status of the contralateral carotid artery has also been thought to influence the need for placing a shunt. The relationship of EEG monitoring, stump pressure, and the contralateral carotid artery has not been completely delineated. We retrospectively reviewed these three variables in 113 patients undergoing 124 carotid endarterectomies. The contralateral artery was classified as occluded, stenotic (greater than 50% decrease in diameter), or nonstenotic. There was a 48% incidence of EEG changes with contralateral occlusion, 18% with stenosis, and 21% with nonstenotic arteries (p = 0.014). There was a 73% incidence of EEG changes when the stump pressure was less than 25 mm Hg, 32% when the stump pressure was 25 to 50 mm Hg, and 2% when the stump pressure was greater than 50 mm Hg (p less than 0.001). There was no significant difference in the mean stump pressure for patients with occlusion (43.8 mm Hg), stenosis (44.7 mm Hg), or nonstenotic contralateral arteries (51.3 mm Hg). All patients with contralateral occlusion and a stump pressure less than 25 mm Hg had EEG changes. No patient with a stump pressure greater than 50 mm Hg and a patent contralateral artery had EEG changes. Although the incidence of EEG changes in the majority of patients was not accurately predicted by the stump pressure and the status of the contralateral carotid artery, stump pressure less than or equal to 50 mm Hg was sensitive, identifying 97% of patients with EEG changes.

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PubMed1991

Microvascular pedal bypass for salvage of the severely ischemic limb.

Bypass to the pedal arteries was performed with use of the operating microscope and standard microsurgical technique in 37 patients with severe, chronic ischemia of a lower extremity. Twenty-one patients (57%) had three or more cardiovascular risk factors, and 22 (59%) had diabetes. Preoperative arteriography identified a pedal artery suitable for bypass in all but one patient. The greater or lesser saphenous vein was used in all patients, most frequently as a nonreversed, translocated vein graft. An arm vein was used as part of a composite graft in only one patient. No early deaths occurred, and only one patient had a perioperative myocardial infarction. Although five grafts occluded within 30 days, four were successfully revised, and 36 patients had a patent graft at the time of dismissal from the hospital. At 1 year, the primary graft patency rate (patency without revision) was 60.8%, and the secondary patency rate was 68.8%. One early and six late amputations were performed; the cumulative 1-year limb salvage rate was 82.4%. Grafts with an intraoperative flow rate of 50 ml/min or more had a better patency rate than those with a lower flow rate. The presence of diabetes did not adversely affect long-term patency. Of the 34 patients who were alive at the time of this report, 27 (79%) had a functional foot that allowed ambulation, had no rest pain, and had no substantial loss of tissue. Pedal bypass should be considered for critical, chronic ischemia, even if the patient has an increased surgical risk and advanced distal atherosclerotic disease.

Adult↗
PubMed1991

Failure of motor evoked potentials to predict neurologic outcome in experimental thoracic aortic occlusion.

Motor evoked potential monitoring was tested as an alternative to somatosensory evoked potential monitoring in evaluating spinal cord function during thoracic aortic occlusion in dogs. Twenty-seven animals underwent 60 minutes of cross-clamping of the proximal descending thoracic aorta with (n = 18) or without (n = 9) cerebrospinal fluid drainage. Spinal cord blood flow was measured with microspheres, and neurologic outcome was evaluated at 24 hours with Tarlov's scoring system. Cerebrospinal fluid drainage improved neurologic outcome (p less than 0.05). Motor evoked potentials recorded over the lumbar spinal cord were lost in 9 of 20 dogs with ischemic cord injury and were not lost in any of the 7 dogs that were neurologically normal. Somatosensory evoked potential were lost in 19 of 20 paraplegic/paraparetic dogs and lost in 3 of 7 normal dogs (p less than 0.01). After reperfusion, motor evoked potentials returned in all nine neurologically injured dogs that lost the potentials and were still present at 24 hours. Changes in amplitude, latency, or time until loss or return of motor evoked potentials or somatosensory evoked potentials did not predict neurologic injury. Loss of somatosensory evoked potentials had a high sensitivity (95%) but had low specificity (67%) because of peripheral nerve ischemia. Loss of motor evoked potentials recorded from the spinal cord had high specificity (100%) but a low sensitivity (46%) and was therefore not a reliable predictor of neurologic injury. Return of motor evoked potentials during reperfusion did not correlate with functional recovery. Motor evoked potentials stimulated in the cortex and recorded from the spinal cord had low overall accuracy (59%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Unusual manifestations of abdominal aortic aneurysms.

Repair of an asymptomatic infrarenal abdominal aortic aneurysm is straightforward and can be accomplished with low morbidity and mortality rates. However, certain complications of abdominal aortic aneurysm, such as contained rupture, inflammatory aneurysm, aortovenous fistula, infected aneurysm, primary aortoenteric fistula, and lower-extremity atheroembolism can be both limb- and life-threatening. Unusual signs and symptoms in a patient with an abdominal aortic aneurysm should alert the physician to the possibility of one of these complications. Careful history-taking and physical examination and appropriate diagnostic imaging, combined with a well-planned operation, will minimize the morbidity and mortality rates otherwise associated with these complications.

Aorta, Abdominal↗
PubMed1989

Effects of thoracic aortic occlusion and cerebrospinal fluid drainage on regional spinal cord blood flow in dogs: correlation with neurologic outcome.

We studied the effect of thoracic aortic occlusion and cerebrospinal fluid (CSF) drainage on regional spinal cord blood flow and its correlation with neurologic outcome. Using isotope-tagged microspheres, we determined blood flow to the gray and white matter of five regions of the spinal cord in dogs: group I (control), group II (cross-clamp only), group III (cross-clamp plus CSF drainage). At 60 minutes after thoracic aortic occlusion in group II, median gray matter blood flow (GMBF) in the lower thoracic and lumbar cord decreased from 23.1 and 27.0 ml/100 gm/min at baseline to 4.0 and 2.5 ml/100 gm/min, respectively. The addition of CSF drainage improved GMBF during aortic cross-clamping in the lower thoracic and lumbar cord to 11.3 (p less than 0.05) and 15.1 ml/100 gm/min (p less than 0.03), respectively. After removal of the aortic cross-clamp, median blood flow more than tripled from baseline blood flow in group II, whereas CSF drainage prevented significant reperfusion hyperemia. Both low GMBF during cross-clamping and reperfusion hyperemia were associated with a worse neurologic outcome. In group II, no dog was neurologically normal, and more than 60% of the dogs had spastic paraplegia. In contrast, almost 60% of dogs in group III were normal, and none had spastic paraplegia (p less than 0.001). We conclude that CSF drainage in dogs during thoracic aortic occlusion maintained spinal cord perfusion above critical levels, diminished reperfusion hyperemia, and improved neurologic outcome.

Animals↗
PubMed1988

Mirizzi syndrome.

The Mirizzi syndrome refers to benign obstruction of the common hepatic duct by a stone impacted within the neck or cystic duct of the gallbladder, which causes extrinsic compression of the common hepatic duct and obstructive jaundice. Although a rare cause of obstructive jaundice, it remains a clinically and surgically challenging problem. Five patients with the Mirizzi syndrome were culled from over 9000 patients undergoing operation for gallstone disease. The management of these patients was detailed. Diagnosis requires a high index of clinical suspicion but can be confirmed with the use of ultrasonography and percutaneous transhepatic cholangiography. Cholecystectomy and common duct exploration are essential components of operative therapy, but additional procedures to repair non-circumferential bile duct defects or strictures must be anticipated.

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PubMedDate not supplied

Intraoperative duplex ultrasound during carotid endarterectomy.

The purpose of this study was to examine the technical aspects of intraoperative duplex ultrasound (DUS) following carotid endarterectomy (CEA), suggest criteria to differentiate significant lesions requiring immediate surgical revision from normal or benign defects, and evaluate how frequently intraoperative DUS provides useful or unsuspected information. A retrospective study was performed on all patients who had both CEA and intraoperative carotid DUS between January 1, 1990, and January 1, 1995. A total of 155 DUS examinations were performed in 149 patients. Findings were grouped into three categories: normal; minor/insignificant lesions; and hemodynamically significant lesions based on the presence or absence of elevated peak systolic velocities, visible stenosis/thrombus, or intimal flap/dissection. Postoperative status was correlated with intraoperative DUS findings. Ninety-one (59%) examinations performed on 87 patients produced normal findings. Forty-seven (30%) examinations performed on 45 patients showed minor abnormalities consisting of insignificant residual plaque, residual external carotid artery stenoses, small intimal flaps, elevated velocities with no associated anatomic lesion, or an arterial kink. Fourteen patients (9%) had significant findings requiring immediate surgical revision. These consisted of large intimal flaps or dissection in six patients, marked residual plaque and significant stenosis in five patients, thrombus in two patients, and a kink in one patient. Three additional patients (2%) had significant findings but were not revised for various reasons. No significant difference was identified in morbidity or mortality rates between those patients with normal findings, those patients with minor technical defects, and those patients with significant abnormalities undergoing immediate surgical revision. However, two of three patients who had significant abnormalities within the common carotid artery that were not revised suffered perioperative ipsilateral strokes. Intraoperative DUS is a safe and accurate method to assess the technical adequacy of CEA. Intraoperative DUS showed significant lesions in 11% of patients. Identification and immediate repair of significant technical defects may decrease perioperative complication rate and long-term restenosis rate.

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PubMedDate not supplied

Renal artery stenosis and a functioning hilar paraganglioma: a rare cause of renovascular hypertension--a case report.

Surgically correctable causes of hypertension are uncommon. Simultaneous occurrence of 2 such causes in the same individual is extremely rare. The authors describe a 25-year-old woman with congenital erythrocytosis, renal artery stenosis, and a paraganglioma. The possible mechanisms of renal artery stenosis in the presence of a catecholamine-secreting tumor are discussed.

Adult↗
PubMedDate not supplied

Failure of selective shunting to intercostal arteries to prevent spinal cord ischemia during experimental thoracoabdominal aortic occlusion.

Paraplegia from spinal cord ischemia during thoracoabdominal aneurysm repair remains an unpredictable and unpreventable complication. In an effort to prevent spinal cord ischemia during aortic cross-clamping, preoperative angiographic localization of the blood supply to the spinal cord was performed in dogs. Sixteen animals underwent 60 minutes of thoracoabdominal aortic cross-clamping either without (control, n = 8) or with (shunted, n = 8) a selective shunt. Shunting was performed from the aortic arch to that isolated aortic segment angiographically shown to supply the thoracolumbar anterior spinal artery. Spinal cord blood flow was measured with microspheres just prior to cross-clamping, at 5 and 60 minutes after cross-clamping and at 5 minutes after restoration of aortic blood flow. Functional neurologic outcome was evaluated in animals at 24 hours postoperatively. Shunting did not decrease spinal cord injury. Seven of the 8 animals in the control group and 7 of the 8 in the shunted group developed paraplegia or paraparesis. Thoracic, but not lumbar spinal cord blood flow, was significantly increased in shunted animals. Spinal cord blood supply in dogs may be more segmental than previously believed. Technical problems in angiographic localization, spinal artery spasm, loss of spinal cord autoregulation or poor collateral circulation from the distal thoracic to the lumbar cord may also account for these results. Although shunting to aortic segments supplying the anterior spinal artery during thoracoabdominal aortic clamping may be attractive in humans, no benefit could be shown in this experimental model.

Angiography↗
PubMedDate not supplied

The current role of surgical revascularization for combined renovascular hypertension and renal insufficiency.

The number of elderly patients presenting with the difficult combination of renovascular hypertension and deteriorating renal function is increasing. The majority of these patients have diffuse cardiovascular disease requiring careful preoperative evaluation and stabilization. Adequate control of hypertension and preservation of renal function frequently requires bilateral renal procedures in addition to aortic replacement in patients with significant aorto-iliac disease or aortic aneurysms. Early and late results continue to justify prompt surgical consultation and revascularization of patients with combined renovascular hypertension and renal insufficiency.

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