Biomedical subjects

Vincent L Rowe

Publications and source records attributed to Vincent L Rowe.

At least 19 recordsLinked to original sources

PubMed2006

Insulin resistance of muscle protein metabolism in aging.

A reduced response of older skeletal muscle to anabolic stimuli may contribute to the development of sarcopenia. We hypothesized that muscle proteins are resistant to the anabolic action of insulin in the elderly. We examined the effects of hyperinsulinemia on muscle protein metabolism in young (25+/-2 year) and older (68+/-1 year) healthy subjects using stable isotope tracer techniques. Leg blood flow was higher in the young at baseline and increased during hyperinsulinemia, whereas it did not change in the elderly. Glucose concentrations and muscle uptake were not different between groups at baseline and during hyperinsulinemia. Leg phenylalanine net balance was not different at baseline and significantly increased in both groups with hyperinsulinemia (P<0.05) but to a greater extent in the young (P<0.05). Muscle protein synthesis increased only in the young during hyperinsulinemia. Muscle protein breakdown did not significantly change in either group, although it tended to decrease in the elderly. Changes in muscle protein synthesis were correlated with changes in leg amino acid delivery (R=0.89; P=0.0001) and blood flow (R=0.90; P<0.0001). In conclusion, skeletal muscle protein synthesis is resistant to the anabolic action of insulin in older subjects, which may be an important contributor to the development of sarcopenia.

Adult↗

PubMed2005

Treatment options for traumatic pseudoaneurysms of the paravisceral abdominal aorta.

Penetrating gunshot wounds (GSWs) to the abdominal aorta are frequently lethal. Alternative management options for treatment of traumatic pseudoaneurysms of the abdominal aorta are illustrated by three patient case histories. Patient A sustained two GSWs to the abdomen (midepigastrium, right subcostal region). He was hypotensive in the field. Emergent laparotomy was undertaken with suture ligature of a celiac injury and distal pancreatectomy/splenectomy for a pancreatic injury. Postoperative abdominal CT for an intraabdominal infection with leukocytosis revealed a 4 cm traumatic pseudoaneurysm of the abdominal aorta that extended from the suprarenal aorta to the level of the renal arteries. Six weeks later, he underwent an open repair. Patient B sustained multiple GSWs to his right arm and right upper quadrant. He was hemodynamically stable. He underwent abdominal exploration for a grade 3 liver laceration. Postoperative abdominal CT revealed a supraceliac abdominal aortic pseudoaneurysm. An aortogram demonstrated a 1.5 cm defect in the aortic wall above the celiac trunk communicating with the inferior vena cava (IVC). He underwent endovascular repair with covered aortic stent graft. Patient C sustained multiple thoracoabdominal GSWs. He was hemodynamically stable. Emergent laparotomy revealed multiple left colonic perforations, two duodenal lacerations, and an unsalvageable left kidney laceration. Postoperatively, he developed a duodenal-cutaneous fistula with multiple intraabdominal abscesses. Serial CT scans revealed an enlarging infrarenal aortic pseudoaneurysm. He underwent angiographic coil embolization and intraarterial injection of thrombin into the pseudoaneurysm sac. The average time from injury to surgical treatment was 46 days (range 29-67). Postoperatively, none of the patients developed paraplegia. Advances in endovascular techniques have provided options to deal with traumatic pseudoaneurysms of the abdominal aorta. In a hemodynamically stable patient with a traumatic pseudoaneurysm, careful selection of a specific intervention can be tailored to the clinical scenario electively.

Adolescent↗

PubMed2005

Neointimal hyperplasia on a cell-seeded polytetrafluoroethylene graft is promoted by transfer of tissue plasminogen activator gene and inhibited by transfer of nitric oxide synthase gene.

OBJECTIVE: The objective of this study was to examine the effect of tissue plasminogen activator (tPA) and endothelial nitric oxide synthase (eNOS) on thrombosis and neointimal hyperplasia on a polytetrafluoroethylene (PTFE) graft seeded with smooth muscle cells (SMCs). METHODS: SMCs retrovirally transduced with tPA and eNOS genes were seeded on PTFE grafts and then implanted into the infrarenal rabbit aorta. Thrombosis and neointimal hyperplasia on the grafts were examined after 30 and 100 days of implantation. RESULTS: At 30 days of implantation, thrombus was observed on the luminal surface of both unseeded and SMC seeded control grafts, whereas grafts seeded with SMCs secreting tPA were nearly free of thrombus. At 100 days, the neointima on grafts seeded with tPA transduced SMCs was significantly thicker (925 +/- 150 microm, n = 5) than neointima on the other grafts (range, 132 to 374 microm; P < .001). Neointima thickness on grafts seeded with eNOS transduced SMCs (154 +/- 27 microm) was similar to that of unseeded grafts (132 +/- 16 microm, P > .05); both were thinner than those on grafts seeded with SMCs transduced with only lacZ gene (287 +/- 35 microm). The ratio of seeded cells in the neointima was significantly higher on SMC/tPA grafts (46% +/- 8%) than SMC/NOS grafts (21% +/- 6%, P < .05), indicating tPA transduced cells proliferated more than eNOS transduced cells. CONCLUSIONS: Engineered tPA expression in seeded SMCs causes significantly more neointimal hyperplasia, despite the favorable inhibition of luminal thrombus. eNOS expression in the seeded cells inhibits neointimal hyperplasia.

Animals↗

PubMed2004

Endovascular management of iliac vein occlusive disease.

Iliac vein occlusive disease presents with either acute or chronic symptoms, both of which can be managed with endovascular techniques. This report summarizes our experience in a small cohort of patients undergoing percutaneous treatment of iliac vein occlusive disease. Six women and one man with occlusive lesions in the iliac veins are included in this report. All patients reported leg pain and swelling, involving the right leg in one and the left leg in six. Symptoms were acute in one patient and chronic in six. Two patients presented with a chronic stasis ulcer. All patients with chronic symptoms were treated with self-expanding stents deployed across the occlusive lesion. The patient with acute symptoms was treated successfully with thrombolysis, which uncovered a fixed stenosis that was then stented. Post-procedure follow-up with duplex scanning was used for vein patency. No significant complications occurred. All patients reported symptomatic improvement, with four having complete resolution. Duplex scanning showed all treated venous segments to be patent at a mean of 12 months. Recanalization of obstructed iliac vein segments can be performed successfully and leads to improvement in pain and edema in the affected limb. Midterm patency rates are excellent.

Adult↗

PubMed2004

Renal revascularization in Takayasu arteritis-induced renal artery stenosis.

PURPOSE: This study was undertaken to define the long-term effects of renal revascularization on blood pressure, and renal and cardiac function in patients with Takayasu arteritis-induced renal artery stenosis (TARAS). METHODS: Twenty-seven patients (25 women; mean age, 27 years) with TARAS underwent intervention. Primary, primary assisted, and secondary patency rates were determined, and the late effects on blood pressure, renal and cardiac function, and survival were analyzed. RESULTS: All patients had hypertension (mean blood pressure, 167/99 mm Hg; 2.5 antihypertensive medications per patient). Mean estimated glomerular filtration rate in patients not receiving hemodialysis was 76 mL/min, and in five patients serum creatinine concentration was greater than 1.5 mg/dL. Three patients were hemodialysis-dependent, and two had intractable congestive heart failure. Forty interventions were performed, including 32 aortorenal bypass procedures, two repeat implantations, four nephrectomies, and two transluminal angioplasty procedures. Postoperative morbidity was 19%. There were no deaths. During follow-up (mean, 68 months), three graft stenoses, all due to intimal hyperplasia, and three graft occlusions occurred. Two of three graft stenoses were successfully revised. At 1, 3, and 5 years of follow-up, primary patency was 87%, 79%, and 79%, respectively; primary assisted patency was 93%, 89%, 89%, respectively; and secondary patency was 93%, 89%, and 89%, respectively. Intervention resulted in a decrease in blood pressure to a mean of 132/79 mm Hg (P<.0001), and the need for antihypertensive medications was reduced to one per patient (P<.01). Mean glomerular filtration rate increased to 88 mL/min (P<.005), and two patients no longer required hemodialysis. Congestive heart failure resolved in both patients, and did not recur. There were three deaths during follow-up, with 5-year and 10-year actuarial survival of 96% and 80%, respectively. CONCLUSIONS: Renal revascularization to treat TARAS is durable, has a salutary effect on blood pressure, and enhances long-term renal and cardiac function. This response establishes renal revascularization as a successful and durable intervention for TARAS, and a benchmark to which other therapies should be compared.

Adult↗

PubMed2004

Basilic vein transposition fistula: a good option for maintaining hemodialysis access site options?

PURPOSE: The primary use of autogenous arteriovenous access for chronic hemodialysis is recommended by the National Kidney Foundation-Dialysis Outcomes Quality Initiative practice guidelines. We review the outcomes of basilic vein transposition (BVT) to assess its value as a primary upper arm arteriovenous access option. METHODS: A retrospective review of 56 patients undergoing BVT was performed. Thirty patients were men; average age was 56 years. Etiology of end-stage renal disease, complications, and time to maturation were tabulated. Primary and secondary patency rates were determined by using life table methods. Multivariate regression analysis was performed to assess risk factors for fistula failure. RESULTS: Renal failure was associated with diabetes in 32 (57%) patients, and BVT was the primary access procedure in 22 (39%) patients. Perioperative complications occurred in 5 (9%) patients and included hematoma (n = 3), myocardial infarction (n = 1), and death (n = 1). The average time to maturation was 74 days (range, 12-265 days), and maturation failure occurred in 21 (38%) patients. Logistic regression analysis showed that age older than 60 years was associated with poorer maturation and patency rates. On an intent-to-treat basis, 1-year primary and secondary patencies were 35% and 47%, respectively, but only 18% and 28%, respectively, for age >60 years. Forty-two percent of failed BVT were subsequently replaced with a prosthetic graft by using the same upper arm vessels. CONCLUSION: BVT frequently do not mature in patients older than 60 years, which compromises its utility as a primary access. However, fistulas that mature provide acceptable patency rates, and subsequent conversion to a prosthetic access is frequently possible. Selective use of BVT might improve the utilization of available access sites.

Arm↗

PubMed2004

Advances in vascular imaging.

The improvement of vascular imaging has allowed the acquisition of vascular images with higher resolution while minimizing the risks and discomfort to patients. As imaging developments continue to progress, establishment of valid clinical-based evidence, before the application of each innovation, will assure maintenance of the current trend. Also, as the vascular surgeon adopts a more comprehensive approach in the care of vascular patients, a high-quality endovascular suite will provide an environment for integration of both traditional open and evolving endovascular procedures.

Angiography↗

PubMed2004

Influence of transmetatarsal amputation in patients requiring lower extremity distal revascularization.

When a transmetatarsal amputation (TMA) is required, successful long-term limb salvage is questioned. We evaluated the influence of TMA on limb salvage in patients undergoing lower extremity revascularization. Patients who had distal bypasses extending to the infrapopliteal arterial tree and adjunctive TMA were retrospectively reviewed. Limb salvage was determined with life-table analysis. Twenty-four patients (29 limbs) were evaluated: 15 male and 9 female. Average age was 64.2 years old. Gangrene was the indication for bypass and TMA in 25 (86.2%) patients. Seven limbs were lost to follow-up. Nine of the remaining 22 limbs required below-knee (8) or above-knee (1) amputations, seven limbs within the first 3 months. In the group of patients who had major amputations within the first 3 months, graft thrombosis was the cause of leg amputation in six (85.7%) cases. No significant predictors of early major amputation were identified. Limb salvage was 62 per cent at 1 year in the TMA group. In comparison, among historical controls requiring distal revascularization and no adjunctive toe or foot amputations, limb salvage was 76.5 per cent (P = NS). Long-term limb salvage is dependent on successful lower extremity revascularization. Requirement for TMA should not influence the decision for limb salvage.

Amputation, Surgical↗

PubMed2003

Rupture of a previously thrombosed thoracoabdominal aneurysm.

Spontaneous thrombosis of abdominal aortic aneurysms is rare. A patient with a 12-cm thoracoabdominal aneurysm developed sudden thrombosis of his aneurysm. He was treated with axillobifemoral bypass. He went on to rupture 7 months later. While spontaneous thromboses of abdominal aortic aneurysms have been previously reported, we did not find any reports of a thrombosed thoracoabdominal aneurysm or a subsequent rupture of this type of aneurysm. The literature on thrombosis of aneurysms is reviewed as well as proposed etiologies for thrombosis and subsequent rupture. We believe that resectional therapy may be warranted even in high-risk patients.

Aged↗

PubMed2003

Analysis of 185 iliac vessel injuries: risk factors and predictors of outcome.

HYPOTHESIS: Iliac vascular injuries incur high mortality. DESIGN: Retrospective 100-month study (January 1, 1992, through April 30, 2000). PATIENTS: One hundred forty-eight patients with 185 iliac vessel injuries. OUTCOME MEASURES: Survival and mortality, analyzed by univariate and logistic regression. RESULTS: Admission mean +/- SD systolic blood pressure was 81 +/- 42 mm Hg, mean Revised Trauma Score was 6.0 +/- 2.8, and mean Injury Severity Score was 20.0 +/- 9.5. The mechanism of injury was penetrating in 140 patients (95%) and blunt in 8 (5%). The mean estimated blood loss was 6246 +/- 6174 mL. Of the 185 injured vessels, 71 (99%) of 72 iliac arteries were repaired, 101 (89%) of 113 iliac veins were ligated, and 12 (11%) of 113 iliac veins were repaired. Overall survival was 51% (76/148). Mortality was 82% (49/72) in patients with exsanguination. Survival by vessel: iliac artery, 57% (20/35); iliac vein, 55% (42/76); and iliac artery and vein, 38% (14/37). Significant predictors of outcome were thoracotomy in the emergency department, associated aortic injury, inferior vena cava injuries, iliac artery and vein injury, intraoperative arrhythmia, and intraoperative coagulopathy. On logistic regression, independent risk factors for survival were absence of thoracotomy in the emergency department, surgical management, and arrhythmia. Mortality by grade on the Organ Injury Scale of the American Association for the Surgery of Trauma (AAST-OIS) was as follows: grade III, 35% (33/95); grade IV, 71% (24/34); and grade V, 79% (15/19). CONCLUSIONS: Mortality remains high. Associated vessel injuries and intraoperative complications predict mortality. AAST-OIS grade for abdominal vascular injuries correlates well with mortality.

Adolescent↗

PubMed2003

The vasculopathic patient: uncommon surgical emergencies.

Recognition of the patient who has an emergent vascular disorder and the early initiation of simple management steps in the ED can significantly impact patient outcome. The vasculopathic patient presents with significant comorbid conditions and a small window of opportunity to alter the prognosis favorably. The critical role of the EP lies in prompt use of this opportunity and appropriate direction of further care.

Axillary Vein↗

PubMed2003

Smooth muscle cells improve endothelial cell retention on polytetrafluoroethylene grafts in vivo.

OBJECTIVE: We investigated the influence of smooth muscle cells (SMC) on endothelial cell (EC) retention on polytetrafluoroethylene (PTFE) grafts and the effect of SMC seeding on intimal hyperplasia in vivo in a rabbit model. METHODS: Fibronectin-coated PTFE grafts (4 mm diameter) were seeded with either EC alone, SMC alone, or SMC followed 24 hours later by EC. The grafts were connected to an extracorporal aortic shunt for 1 hour or were individually implanted for 1, 30, and 100 days into the infrarenal aorta as an end-to-side bypass graft. The number of retained cells was compared at 1 hour and at 1 day after implantation. Neointimal thickness was measured 30 and 100 days after implantation. RESULTS: After 1-hour exposure to blood flow, EC retention rate was greater (P <.005) if seeded on top of SMC (98% +/- 2%; n = 8) versus being seeded alone (65 +/- 11%; n = 8). SMC retention rate was 95 +/- 5% (n = 8) when seeded alone. Similar cell retention was obtained 1 day after implantation. After 30-day implantation the neointima was thicker in grafts seeded with EC and SMC (282 +/- 136 microm; n = 3) than with EC only (52 +/- 45 microm; n = 3; P <.001). However, the neointimal thickness for dual-cell-seeded grafts (126 +/- 60 microm; n = 3) was not significantly different (P =.09) from EC-seeded grafts (79 +/- 48 microm; n = 3) after 100-day implantation. CONCLUSION: EC retention on PTFE grafts in vivo is improved if seeded over a layer of SMC. Further studies are needed to determine whether overlying EC modulate proliferation of underlying SMC.

Animals↗

PubMed2002

The utility of preoperative routine carotid artery duplex scanning in patients undergoing aortic valve replacement.

Patients with aortic valve disease (AVD) typically have a cardiac murmur that radiates to the neck and may be indistinguishable from a cervical bruit secondary to carotid artery occlusive disease. The purpose of this report was to determine the prevalence of significant asymptomatic carotid artery occlusive disease in patients undergoing aortic valve replacement (AVR). All patients scheduled for AVR were prospectively studied. Preoperative carotid artery color-flow duplex was performed in all patients. A total of 204 patients were included in the study and significant carotid disease (>50% stenosis of the internal carotid artery) was found in 17 (8%). In patients with isolated aortic valve disease, 4/129 (3%) had significant stenosis. Of the patients with concurrent aortic valve and coronary artery disease, 13/75 (17%) had significant stenosis. The incidence of significant carotid stenosis in patients with aortic valve disease was over five fold higher in patients with concurrent coronary artery disease (3% vs. 17%, p <0.001). The yield of routine carotid duplex scanning for patients undergoing isolated AVR is low. However, in the subset of patients with concurrent coronary disease, the yield is higher. This finding supports the use of routine carotid duplex scanning in patients with coexistent aortic valve and coronary artery disease.

Adult↗

PubMed2002

Initial experience with dorsal venous arch arterialization for limb salvage.

Surgical reconstruction for patients with symptomatic lower extremity arterial occlusive disease is successful when a suitable distal target vessel is present. In patients with unreconstructable disease, practical surgical options are at a minimum. We report our initial experience with dorsal venous arch arterialization (DVAA) for limb salvage. Patients with a lower extremity arteriogram and tibia/plantar artery duplex scan demonstrating unreconstructable occlusive disease were evaluated for DVAA. The venous arch valve lysis technique consisted of retrograde balloon catheter, arterial dilator disruption, and direct valvulectomy. Outcome variables included patency, limb salvage rate, and toe pressure alterations. Initial results suggest that DVAA may be a viable option for end-stage limb salvage. Application of the DVAA appears to be more suitable for patients with symptoms secondary to atherosclerosis than those with Buerger's disease.

Adult↗

PubMed2002

Concomitant vascular procedures for malignancies with vascular invasion.

HYPOTHESIS: Contemporary reconstructive vascular techniques can be safely used to permit resection of tumors invading major vascular structures. DESIGN: Review of vascular surgery registry between January 1, 1987, and December 31, 2001. SETTING: An academic medical center and affiliated institutions. PATIENTS: Forty-nine patients (37 males and 12 females) aged 15 through 80 years (mean age, 55 years) who required concomitant vascular resection and reconstruction to allow complete tumor resection. MAIN OUTCOME MEASURES: Early (<30 days) morbidity and mortality, late (>30 days) vascular morbidity and mortality, primary patency of the vascular reconstruction, and tumor-free survival. RESULTS: Aortic resection with graft reconstruction was performed in 20 patients (41.7%) and inferior vena cava resection with reconstruction in 6 patients (12.5%). Five patients (10.4%) had both the aorta and inferior vena cava resected and reconstructed. Iliac, femoral, or popliteal reconstructions were performed in 15 patients (31.3%). Portal vein reconstruction was performed to permit resection of pancreatic neoplasms in 8 patients (16.7%). Resection and reconstruction of either a brachiocephalic vessel or superior vena cava was performed in 4 patients. Thirty-day mortality was 2.1%, as 1 patient died of a myocardial infarction following tumor resection with vascular reconstruction. Overall 30-day morbidity was 12.2%. Early vascular morbidity included bleeding from an arterial anastomosis and a compartment syndrome requiring fasciotomy. Primary patency of the vascular reconstructions at 24 months was 90% and tumor-free survival was 70%. Thirty-one patients (63%) were alive, without tumor recurrence and with a patent vascular reconstruction at 24 months. No patient died or lost a limb due to occlusion of the vascular reconstruction. CONCLUSION: Contemporary reconstructive vascular procedures permit resection of tumors that involve major vascular structures with acceptable early and late morbidity and mortality.

Adolescent↗

PubMed2002

Injury induced neointima formation and its inhibition by retrovirus-mediated transfer of nitride oxide synthase gene in an in-vitro human saphenous vein culture model.

Human saphenous veins were cultured to characterize neointima formation and feasibility of gene transfer to inhibit the intimal proliferative response to injury. Mechanical injury was introduced by abrading the luminal surface of the vein patch with a sterile cotton bud. Both injured and non-injured vein patches were cultured and transduced with retroviral vectors carrying marker or therapeutic genes. After a 14-day culture, the thickness of the intimal layer of non-injured vein patches reached 90+/-28 microm at the edge and 61+/-22 microm at the center (n=29) from the original 22+/-12 microm at harvest (n=6, P=0.02). Mechanical injury to the intimal surface prior to culture resulted in an exaggerated proliferative response. The intimal thickness of injured vein patches increased from 3.4+/-1 microm right after injury to 128+/-23 microm (n=12, P<0.001) at the edge after 14-day culture. Genes were transduced efficiently into a luminal layer of cultured veins using a pseudotyped murine leukemia viral vector. Transduction of gene encoding nitric oxide synthase resulted in reduction of neointima formation to 33+/-7 microm (n=12) at the edge after 14-day culture compared to 90 microm (P<0.01) seen in untransduced non-injured vein patches. Marker gene transduction did not alter intimal proliferative response or its immunohistochemical profile. The data suggest that cultured vein can be used as a model for studying the effects of injury to blood vessels and to evaluate the effects of candidate therapeutic genes.

Cells, Cultured↗

PubMed2002

Shank vessel injuries.

The management of lower extremity vascular injuries has undergone dramatic changes over the last century. With the optimal management of femoral and popliteal injuries established, controversy still exists with respect to management of vascular injuries below the popliteal fossa, in the shank arterial vessels. These injuries are uncommon, often limb threatening, and usually require complex management decisions. Incidence of shank vessel injuries, imaging studies required for accurate and expedient diagnosis, determinants influencing the decision for repair or amputation, and details of techniques in surgical intervention are discussed.

Amputation, Surgical↗

PubMed2002

Clinical importance of the "seat belt sign" in blunt trauma to the neck.

Currently a carotid duplex scan is the initial screening modality routinely used to evaluate occult extracranial carotid artery injuries secondary to blunt neck trauma. The objective of this study was to investigate the role of carotid artery duplex scanning in patients who suffered blunt trauma to the neck with a "seat belt sign." The medical records of 131 consecutive patients who sustained blunt trauma to the neck from a motor vehicle accident were reviewed. Patients with the cervical seat belt sign underwent a complete physical examination and carotid duplex scan in an accredited vascular laboratory. An intimal flap with severe carotid artery stenosis was found in one of 131 patients (0.76%). This patient has multiple injuries to the face, head, chest, lateralizing neurological signs, and a Glasgow Coma Scale score of 8. In an era of cost containment, resource consumption should target appropriate populations. A cervical seat belt sign should not serve as a sole indicator for evaluation of the carotid artery in the absence of other pertinent signs or symptoms.

Accidents, Traffic↗