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Biomedical subjects

W C Sternbergh

Publications and source records attributed to W C Sternbergh.

At least 19 recordsLinked to original sources
PubMed2003

Brave new world: the role for endovascular aneurysm repair in contemporary vascular surgery.

Endovascular abdominal aortic aneurysm repair (EVAR) poses certain challenges to the vascular surgeon. Based upon our 6-year experience, we have highlighted important aspects of patient selection. EVAR can be performed in patients with significant co-morbidities, but technical success may be limited by anatomic criteria. Short to mid-term outcomes report low mortality and morbidity from EVAR. Acute and delayed conversion, rupture, endoleak, limb occlusion, and migration are complications occurring in EVAR; their frequency, presentation and management are described. EVAR has up to 90% success rate at several years follow-up including the use of secondary procedures. Secondary procedures are not infrequent after EVAR; thus close follow-up is of the utmost importance. We predict that EVAR will continue to be a valuable tool in the future.

Aortic Aneurysm, Abdominal↗
PubMed2001

Comparison of open transabdominal AAA repair with endovascular AAA repair in reduction of postoperative stress response.

Operative intervention causes a necessary biologic response known as the hypermetabolic stress response. Less invasive operative procedures may cause fewer metabolic and endocrine derangements. To evaluate the metabolic and endocrine differences between endovascular and transperitoneal abdominal aortic aneurysm (AAA) repair, 10 patients underwent standard open repair (open group) and 10 patients underwent endovascular repair of AAA (endovascular group) with a modular bifurcated endograft. Blood samples were obtained prior to general anesthesia (baseline) and every 6 hr for a 24-hr period. Assays for hormones related to the postoperative stress response as well as retinol-binding protein were performed. Peak hormonal values are presented in relation to the baseline. Demographic analysis of the two groups showed that there were no significant differences in age or ASA classification. The open group had a 9.6-fold increase in epinephrine release, which was significantly higher than the 1.6-fold increase in the endovascular group (p < 0.05). Elevations in cortisol were also significantly higher in the open group. Early postoperative nutritional derangements, as reflected by the levels of retinol-binding protein, were far less in the endovascular group than in the open group. Endovascular AAA repair appears to be associated with a marked reduction in the hypermetabolic stress response and nutritional deterioration, compared to traditional open repair. This reduction in physiologic stress may have salutary effects on the incidence of postoperative medical morbidity.

Abdominal Muscles↗
PubMed2001

Multicenter evaluation of a polyurethaneurea vascular access graft as compared with the expanded polytetrafluoroethylene vascular access graft in hemodialysis applications.

OBJECTIVES: The purpose of this study was to compare in a randomized, prospective, and controlled study, the performance of a multilayered, self-sealing polyurethane vascular access graft (PVAG) and expanded polytetrafluoroethylene (ePTFE) vascular access grafts in hemodialysis applications. Performance measures included graft survival, complications, time to early cannulation, and hemostasis times after cannulation. STUDY DESIGN: A total of 142 patients were randomized equally to receive one of the two grafts after meeting all eligibility requirements. All patients were followed up prospectively to 12 months or to the end of secondary patency. Specifically, this study documented the performance of the PVAG and ePTFE grafts by determining the patencies and complications for both grafts. RESULTS: Patient characteristics between the two groups were similar with respect to risk factors and demographic characteristics (P >.05). Life-table patencies from the date of first dialysis were primary patency: PVAG 55% versus ePTFE 47% (6 months) and PVAG 44% versus ePTFE 36% (12 months) and secondary patency: PVAG 87% versus ePTFE 90% (6 months) and PVAG 78% versus ePTFE 80% (12 months). None of these differences were significant (P >.05). Both primary and secondary patencies were also not significantly different when the date of implantation was the starting point. Adverse events and complications were similar for the two groups, except the PVAG group had a higher incidence of technical complications manifested by graft kinking when compared with the control cohort (P <.05). Additionally, there was no significant difference in complication rates between these two groups with regard to infection and bleeding. When the time to hemostasis after cannulation was compared at 5minutes or less, there were more PVAG cannulation sites that achieved hemostasis compared with ePTFE sites, and this difference was significant (P <.0001). When time to first dialysis access was compared between the two grafts, 53.9% of all PVAG grafts were cannulated before 9 days versus none with the ePTFE grafts (P <.001). However, long-term graft survival was not significantly different when PVAG patients were stratified into early (< 9 days) and the late access (9 >/= days) groups (P =.29). CONCLUSIONS: The PVAG graft allows for early access without compromising long-term performance. Both PVAG and standard ePTFE grafts have similar long-term outcomes, despite early access with the PVAG vascular access grafts.

Biocompatible Materials↗
PubMed2001

Influence of NASCET/ACAS trial eligibility on outcome after carotid endarterectomy.

PURPOSE: Proponents of carotid angioplasty and stenting suggest that "high risk" patients, defined as patients excluded from the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Asymptomatic Carotid Atherosclerosis Study (ACAS), may have a significantly higher risk of stroke with carotid endarterectomy (CEA). However, this selected patient cohort has been poorly studied. METHODS: A retrospective review of patients who underwent CEA during a 2-year period at a tertiary referral institution was performed. Each patient was evaluated and categorized, according to the exclusion criteria, by NASCET and ACAS standards. Statistical analysis using chi(2) and Fisher exact tests was performed. RESULTS: There were 366 CEAs performed on 348 patients, including 32 (8.7%) for recurrent stenosis. A subgroup of 169 (46.2%) patients were trial ineligible. Focal ipsilateral symptoms were present in 148 (40.4%) of the patients. There were 9 (2.5%) strokes and 1 (0.3%) death, secondary to a major stroke, for an overall stroke and death rate of 2.5%. Trial-eligible patients had a stroke/death rate of 1.5% (3/197) while trial-ineligible patients had a 3.6% (6/169) stroke/death rate (P = .17). CONCLUSION: Patients who were considered high risk for CEA as defined by trial ineligibility were common, comprising approximately half of our patients. Although trial-ineligible patients had a nonsignificant trend toward higher neurologic morbidity when compared with the eligible group, the risks were still comparable with NASCET/ACAS results. CEA was a safe procedure even in this "high risk" group. As such, ineligibility for a randomized carotid intervention trial should not be employed as a "de novo" indication for carotid stenting.

Aged↗
PubMed2000

Orally administered unfractionated heparin with carrier agent is therapeutic for deep venous thrombosis.

BACKGROUND: Orally administered heparin (OHEP) is unreliable because of poor absorption. Sodium N-(8[2-hydroxybenzoyl]amino) caprylate (SNAC) is an amido acid that facilitates the gastrointestinal absorption of heparin. We evaluated the effectiveness of OHEP combined with SNAC (OHEP/SNAC) in the treatment of deep-vein thrombosis (DVT). METHODS AND RESULTS: An internal jugular DVT was produced in 54 male Sprague-Dawley rats. Animals were assigned to 6 different groups for 7 days of treatment: untreated control, subcutaneous heparin (SC HEP) (300 U/kg SC TID), SNAC only (300 mg/kg PO TID), OHEP only (30 mg/kg PO TID), low-molecular-weight heparin (LMWH) (enoxaparin 5 mg/kg SC QD), and OHEP/SNAC (30 mg/kg:300 mg/kg PO TID). The activated partial thromboplastin time (aPTT) and anti-factor X (anti-Xa) levels were measured. The incidence of residual DVT after 1 week of treatment was 100% (9 of 9) in the control group versus 10% (1 of 10) in the OHEP/SNAC and 10% (1 of 10) in the LMWH groups (P<0.001). There was also a significant reduction in clot weights between these groups. Compared with controls, there were no significant differences in the residual DVT in the SNAC-only (6 of 6), OHEP-only (9 of 9), or SC HEP (8 of 10) groups. Combination OHEP/SNAC was as effective in the resolution of the clot and reducing clot weight as LMWH. The aPTT levels in the OHEP/SNAC group peaked at 30 minutes and were significantly higher than in all other groups (P<0.01). Anti-Xa levels were elevated at 15 minutes after dosing in the OHEP/SNAC group and remained significantly elevated at 4 hours (P<0.001). CONCLUSIONS: OHEP combined with a novel carrier agent (SNAC) successfully treated DVT in this rat model.

Administration, Oral↗
PubMed2000

Hospital cost of endovascular versus open repair of abdominal aortic aneurysms: a multicenter study.

BACKGROUND: Technology-driven innovation in medicine is frequently associated with higher costs than conventional therapy. A significantly higher cost for endovascular ($21,250, n = 190) versus open abdominal aortic aneurysm (AAA) repair ($12,342, n = 60) was suggested by a direct cost analysis of patients in a multicenter trial. Estimated inpatient costs (not charges) incurred nationwide by hospitals for endovascular and open repair of AAA were studied to validate these observed trends. METHODS: A retrospective analysis of 131 patients undergoing endovascular AAA repair was compared with 49 patients undergoing open repair as part of a Food and Drug Administration phase II prospective multicenter clinical investigation (AneuRx-Medtronic). A model to estimate costs was constructed using important clinical descriptors of these patients. These clinical characteristics where then matched with those from 22, 460 patients undergoing AAA repair obtained from a large national database (Medicare Provider Analysis and Review). Estimated hospital cost was then assigned to each study patient according to the national average of the total hospital costs for the respective matched patients in Medicare Provider Analysis and Review. RESULTS: Total inpatient hospital costs of endovascular repair were significantly higher than that of open repair ($19,985 +/- 7396 versus $12,546 +/- 5944, respectively, P =.0001). Endograft device cost ($10,400) accounted for 52% of the total cost of endovascular repair. The 1999 mean blended Medicare reimbursement for AAA repair was $18,989. CONCLUSION: In this early development stage, hospital cost for endovascular AAA repair is significantly greater than open repair when device cost greatly exceeds $5000. Although incremental reductions in cost of endovascular repair may be anticipated if use of diagnostic studies, operating time, and length of stay decrease, device cost has the single greatest impact on the expense of endovascular AAA repair. At current device pricing, mean blended Medicare reimbursement does not cover the cost of endovascular AAA repair.

Aged↗
PubMed2000

Treatment of experimentally induced caval thrombosis with oral low molecular weight heparin and delivery agent in a porcine model of deep venous thrombosis.

OBJECTIVE: This experiment evaluated enterally administered low molecular weight heparin (LMWH) combined with sodium N-[10-(2-hydroxybenzoyl)amino] decanoate (SNAD) for the treatment of induced venous thrombosis. SUMMARY BACKGROUND DATA: SNAD is a delivery agent that potentiates the gastrointestinal absorption of LMWH. METHODS: Forty female pigs were equally assigned to four groups: control (saline); enteral LMWH, 2,000 IU/kg; enteral SNAD, 50 mg/kg; and enteral LMWH, 2,000 IU/kg and SNAD, 50 mg/kg. Under fluoroscopic guidance, the infrarenal vena cava was occluded with a balloon catheter. Two milliliters of ethanol was injected into the distal vena cava. The inflated balloon catheter remained in situ for 5 days, at which time animals angiographically exhibiting thrombus were randomly assigned to the four groups. Study medications were dosed at 12-hour intervals by means of a gastrostomy tube placed previously. After 7 days of treatment, thrombus was extracted. A separate group of 10 animals was used to measure plasma antifactor Xa levels for 6 hours after enteral dosing of LMWH/SNAD. RESULTS: The amount of residual thrombus after treatment with enteral LMWH/SNAD was significantly decreased. Antifactor Xa levels were significantly elevated in the LMWH/SNAD group versus baseline. CONCLUSION: The combination of enterally administered LMWH and SNAD given for 7 days appeared to decrease caval thrombosis in this model of deep vein thrombosis. Enteral LMWH/SNAD effected an increase in plasma levels of antifactor Xa.

Animals↗
PubMed2000

Endovascular treatment of multiple visceral artery paradoxical emboli with mechanical and pharmacological thrombolysis.

PURPOSE: To report a case of paradoxical emboli to multiple visceral vessels treated with both mechanical (AngioJet device) and pharmacological (urokinase) thrombolysis. METHODS AND RESULTS: A 72-year-old man presented with a 48-hour history of symptomatic right renal ischemia, which was treated with heparinization. Five days later, an abrupt creatinine elevation prompted arteriography, which demonstrated thromboembolism of the superior mesenteric artery (SMA) and both renal arteries. The AngioJet aspiration device was employed to successfully remove the clot from the SMA; urokinase infusion restored flow to the left kidney. At the 16-month follow-up evaluation, the patient was normotensive without medication and had a stable creatinine (1.4 mg/dL). CONCLUSIONS: Because of its speed and minimal morbidity, the AngioJet device may be an attractive alternative to surgical embolectomy or pharmacological thrombolysis in highly selected cases of acute visceral artery thromboembolism.

Aged↗
PubMed2000

Acute renal failure after redo thoracoabdominal aortic aneurysm repair in a patient with a solitary kidney: successful percutaneous treatment.

PURPOSE: To report the successful percutaneous treatment of renal artery stenosis that precipitated renal failure following surgical repair of a thoracoabdominal aortic aneurysm (TAAA). METHODS AND RESULTS: A 70-year-old woman with a solitary kidney became anuric 2 hours after urgent repair of a symptomatic true aneurysm of the Carrel patch from an 8-year-old TAAA repair. After medical treatment failed, aortography was performed, identifying complete occlusion of the solitary renal artery. Balloon dilation and implantation of a Palmaz stent restored renal perfusion and improved function. At 6-month follow-up, she was normotensive and her creatinine within normal limits. CONCLUSIONS: Renal artery stenosis or occlusion is a treatable cause of acute renal failure after TAAA repair. Percutaneous treatment options are likely to be better tolerated than surgical revascularization in this patient population.

Acute Kidney Injury↗
PubMed1999

Complications associated with percutaneous closure devices.

BACKGROUND: In an effort to reduce time to hemostasis after angiography, several closure devices have been marketed. We report some of their complications. METHODS: A retrospective review was conducted. RESULTS: Over an 8-month study period, 2,181 diagnostic and interventional procedures were performed. Closure devices were used in 408 (19%) of these patients. The Angio-Seal closure device is composed of a collagen sponge and an absorbable polymer anchor that compresses the hole in the arteriotomy. The ProstarXL sealing device consists of a rotating barrel that deploys 4 needles through the arteriotomy, and then individual knots are extracorporeally tied. The Duett device consists of a balloon occluding catheter and injectable collagen and thrombin. Ten of the patients developed a complication from the closure device (2.5%). Four of these were subcutaneous abscesses. Two of these patients had expanding pseudaneurysms, 2 had lower extremity ischemia, and 1 patient had an acute bleed. These complications were all managed surgically. Another patient developed a retroperitoneal bleed that was managed nonoperatively. CONCLUSIONS: As the use of these devices increase, these complications will become more common.

Hemostatic Techniques↗
PubMed1999

Oral low-molecular weight heparin and delivery agent prevents jugular venous thrombosis in the rat.

PURPOSE: Sodium N-[10-(2-hydroxybenzoyl)amino]decanoate (SNAD) is a novel carrier that allows the gastrointestinal absorption of low-molecular weight heparin (LMWH). The purpose of this experiment was to evaluate oral LMWH with SNAD for the prevention of deep venous thrombosis. METHODS: Sixty Sprague-Dawley rats were equally assigned to five experimental groups: group 1 (control), oral saline solution; group 2, oral LMWH (15 mg/kg); group 3, oral SNAD (300 mg/kg); group 4, subcutaneous LMWH (5 mg/kg); and group 5, oral LMWH (15 mg/kg) and SNAD (300 mg/kg). After treatment, the jugular vein was isolated, occluded, and bathed in an ethanol and formalin solution for 2 minutes. Two hours later, the vessel was examined for patency, presence of thrombus, and thrombus weight. Serum measurement of anti-factor Xa activity was performed in a separate set of 30 rats, which were placed into the following four groups: group A, LMWH (5 mg/kg); group B, oral LMWH (15 mg/kg) and SNAD (300 mg/kg); group C, oral LMWH (15 mg/kg); and group D, SNAD (300 mg/kg). RESULTS: The animals that underwent oral LMWH/SNAD therapy had a statistically significant decrease in visible thrombi. The thrombus weight of the oral LMWH/SNAD group was significantly less than the weights of all other groups, except the subcutaneous LMWH group. Anti-factor Xa levels were significantly elevated in the LMWH/SNAD group. There was no statistically significant difference between the data for the oral LMWH/SNAD group and the subcutaneous LMWH group. CONCLUSION: The combination of oral LMWH and SNAD prevented deep venous thrombosis. The oral LMWH and SNAD therapy effected an increase in levels of anti-factor Xa.

Administration, Oral↗
PubMed1999

Carotid endarterectomy in patients with significant renal dysfunction.

PURPOSE: Recent reports suggest that carotid endarterectomy (CEA) should not be performed in patients with end-stage renal disease (ESRD) because of an unacceptable rate of perioperative stroke and other morbidity. Because these conclusions were based on a small number of patients, we reviewed the perioperative and long-term outcome of patients with ESRD and chronic renal insufficiency (CRI) who underwent CEA at our institution. METHODS: The 1081 patients who had a CEA between 1990 and 1997 were cross-referenced with those patients in whom renal insufficiency had been diagnosed. These charts were reviewed for patient demographics and perioperative and long-term outcome. Patients undergoing CEA during a 1-year period (1993) served as controls. RESULTS: Fifty-one CEAs were performed in 44 patients with CRI (32 in 27 patients) and ESRD (19 in 17 patients). In the CRI+ESRD group, 66.7% were symptomatic, and 70.7% of the control group were symptomatic. Six operations (11.8%) in the CRI+ESRD group were redo endarterectomies. There were no perioperative strokes in the CRI+ESRD group, but one patient died 29 days postoperatively because of a myocardial infarction, for a combined stroke-mortality rate of 2.0%. The control group had a 2.6% combined stroke-mortality rate. Long-term survival analysis revealed a 4-year survival rate of 12% for patients with ESRD and 54% for patients with CRI, compared with 72% for controls (P <.05). CONCLUSION: CEA can be performed safely in patients with ESRD or CRI, with perioperative stroke and death rates equivalent to that of patients without renal dysfunction. However, the benefit of long-term stroke prevention in the asymptomatic patient with ESRD is in question because of the high 4-year mortality rate of this patient population.

Aged↗
PubMed1998

Orally administered heparin for preventing deep venous thrombosis.

BACKGROUND: Sodium N-(8-[2-hydroxybenzoyl] amino) caprylate (SNAC) is an acetylated amino acid molecule that facilitates the gastrointestinal absorption of heparin. This study was undertaken to evaluate the efficacy of orally administered combination SNAC:heparin in preventing deep venous thrombosis in a standard rat model. METHODS: Forty-four adult male Sprague-Dawley rats were randomly divided into five groups: group I control, group II SNAC, group III oral heparin, group IV combination SNAC:heparin, and group V intravenous heparin. Thirty minutes after drug administration, the internal jugular vein was bathed in a sclerosant mixture for 2 minutes and reexplored at 120 minutes. Activated partial thromboplastin times (aPTT) were measured in 30 rats equally divided into three groups: group I SNAC, group II oral heparin, and group III combination SNAC:heparin. Forty-five minutes posttreatment, blood was obtained for aPTT levels. RESULTS: The incidence of deep venous thrombosis in the control group was 89% (8 of 9) versus 25% (2 of 8) in the combination SNAC:heparin group (p < 0.01). There was also a significant reduction in clot weight among groups. Combination SNAC:heparin significantly increased aPTT levels compared with SNAC or oral heparin alone. CONCLUSION: In a rat model of venous thrombosis, combination of orally administered heparin:SNAC elevated aPTT levels and significantly reduced the formation of deep venous thrombosis.

Administration, Oral↗
PubMed1998

Abdominal and thoracoabdominal aortic aneurysm.

Most abdominal aortic aneurysms (AAA) and thoracoabdominal aortic aneurysms (TAAA) are asymptomatic and are found on physical exam or incidentally during radiological studies for other indications. These aneurysms are repaired primarily because their risk of rupture increases geometrically as the size exceeds 5 cm. The potential morbidity of intraoperative visceral and spinal ischemia involved with TAAA repair may be reduced with various adjunctive maneuvers.

Aortic Aneurysm, Abdominal↗
PubMed1998

Management of severe proximal vascular and neural injury of the upper extremity.

PURPOSE: Early amputation has been suggested to be the optimal treatment for severe combined vascular and neural injuries of the proximal upper extremity. This retrospective study was done to evaluate the long-term clinical outcome of our policy of limb salvage by revascularization and delayed treatment of neural injuries. METHODS: Forty-six patients with neural and vascular trauma to the upper extremity were treated at our institution. All of these patients had aggressive treatment directed at limb salvage with restoration of vascular supply and nerve function. Long-term vascular and neurologic outcomes were recorded. Neurologic deficits were validated by the American Medical Association's standardized disability impairment scale (0% to 100%). RESULTS: The rate of preoperative disability was 83%, which improved to 52% (p < 0.01) after treatment (mean follow-up, 43 months). Overall, 87% showed improvement. CONCLUSION: These results suggest that early amputation should not be performed unless there is massive tissue loss or an attempt at limb salvage might endanger life. Final outcomes cannot be predicted on the basis of initial clinical presentation. As a group, the majority of these patients improved with aggressive intervention.

Adolescent↗