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Biomedical subjects

B Toursarkissian

Publications and source records attributed to B Toursarkissian.

At least 19 recordsLinked to original sources
PubMed1998

Surgical treatment of patients with symptomatic vertebrobasilar insufficiency.

We report our experience with surgical management of symptomatic vertebrobasilar insufficiency (VBI). Forty revascularizations were carried out in 39 patients over 90 months. Dizziness (52%) and syncope/presyncope (32%) were the most common symptoms. Arteriography was performed in all patients, with subclavian steal seen in 55% of patients. Procedures performed included 22 cases of carotid-subclavian bypass or transposition (55%), seven direct vertebral reconstructions (17.5%), four great vessel reconstructions (10%), four isolated carotid endarterectomies (10%), and three axilloaxillary bypasses (7.5%). One patient died, and the combined morbidity and mortality rate was 15%. Outpatient follow-up was available on 37 of the 38 patients discharged alive. At a mean follow-up of 16.4 months, 34 patients had no VBI complaints. Three of four patients treated with CEA alone had persistent VBI complaints. We conclude that a variety of anatomic lesions can result in VBI symptoms, with subclavian steal being the most common. Procedures which directly correct the anatomic abnormality result in sustained symptom resolution with acceptable complication rates.

Aged↗
PubMed1997

Surgical treatment of thoracic outlet compression syndromes. II. Supraclavicular exploration and vascular reconstruction.

Supraclavicular exploration has become a widely utilized, versatile, and effective approach in the treatment of thoracic outlet compression syndromes. It is applicable to neurogenic, arterial, and venous form of TOS. Although certain aspects of the surgical anatomy are quite familiar to most vascular surgeons, considerable attention must be given to the details of this procedure to avoid inadequate decompression, serious injury, or predictable causes of recurrent compression. Supraclavicular exploration and its variations provide an excellent approach to the entire spectrum of problems encountered in patients with TOS, and in many centers it has superceded the transaxillary approach previously popularized for these disorders. Because supraclavicular exploration for TOS involves a number of unique technical considerations and because it is typically applied to a difficult clinical problem outside the routine experience of most vascular surgeons, it should be undertaken only with appropriate training and interest in the comprehensive management of patients with TOS.

Blood Vessel Prosthesis↗
PubMed1997

Ischemic colitis.

This article contains a current review of ischemic colitis, including its etiology, pathophysiology, diagnostic modalities, and treatment options. A special emphasis is given to ischemic colitis following aortic reconstruction.

Aortic Aneurysm, Abdominal↗
PubMed1997

Arterial thrombosis induces early upregulation of intercellular adhesion molecule in the media.

PURPOSE: Thrombosed peripheral vessels that are pharmacologically or mechanically recanalized have diminished long-term patency rates compared with vessels that are repaired before occlusion. We hypothesized that thrombosis induces proinflammatory changes in the arterial media that may contribute to postthrombotic vascular remodeling. METHODS: We studied expression of intercellular adhesion molecule (ICAM), a mediator of leukocyte recruitment, in the arterial wall after thrombosis. Thrombosis was induced in rabbit superficial femoral arteries by embolizing polystyrene beads (Thr-emb) or by ligation (Thr-lig). Control vessels were dissected but not ligated (C-dis) or were subjected to bead embolization and immediate removal (C-emb). Arterial wall ICAM expression was measured by indirect immunohistochemical analysis at 6 hours, 24 hours, and 1 week. Staining intensity was graded from 0 (none) to 4 (intense) by observers who were blinded to the experimental conditions. RESULTS: No increase in ICAM expression by thrombosed vessels was present at 6 hours. After 24 hours, ICAM expression in the media of thrombosed vessels was increased (Thr-emb, 2.3 +/- 0.5; Thr-lig, 2.0 +/- 0) compared with control vessels (C-dis, 0 +/- 0; C-emb, 0.8 +/- 0.5; p < 0.004). This difference became more marked at 1 week. ICAM staining localized to actin-staining regions of the media. CONCLUSIONS: Arterial thrombosis, but not surgical injury, induces pronounced early and sustained upregulation of ICAM expression in smooth muscle-containing regions of the arterial media. Upregulation of ICAM is likely to promote recruitment of inflammatory cells or mediate vascular remodeling after luminal thrombosis.

Animals↗
PubMed1997

Spontaneous closure of selected iatrogenic pseudoaneurysms and arteriovenous fistulae.

PURPOSE: We report our approach to the management of postcatheterization femoral artery pseudoaneurysms and arteriovenous fistulae in an attempt to determine the frequency of spontaneous resolution of selected lesions. METHODS: We studied 196 pseudoaneurysms, 81 arteriovenous fistulae, and 9 combined lesions that were identified by duplex scan. Indications for immediate surgical repair included pseudoaneurysm greater than 3 cm, enlarging hematoma, pain, groin infection, nerve compression, limb ischemia, concomitant surgical procedure, and patient refusal or inability to comply with follow-up. All other lesions were observed. RESULTS: One hundred thirty-nine patients underwent prompt surgical repair, and 147 patients were initially managed without operation. There were no limb-threatening complications associated with nonoperative management in this subset of patients. Eighty-six percent of the lesions being observed resolved spontaneously within a mean of 23 days, whereas 14% required surgical closure for a variety of reasons (at a mean of 111 days after the initial diagnosis). There was no statistically significant difference in the rate of spontaneous pseudoaneurysm closure (89%) as opposed to fistulae (81%) (p < 0.17). By life-table analysis, 90% of selected pseudoaneurysms had resolved by 2 months. Patients selected for observation underwent an average of 2.6 duplex scans per patient versus 1.4 scans per patient for those treated with immediate surgery (p < 0.01). CONCLUSION: The natural history of stable pseudoaneurysms and arteriovenous fistulae is benign and frequently results in spontaneous resolution, which allows properly selected patients to be managed without operation.

Analysis of Variance↗
PubMed1997

Thrombogenicity of small-diameter prosthetic grafts: relative contributions of graft-associated thrombin and factor Xa.

PURPOSE: We evaluated the contributions of coagulation factors IIa (thrombin) and Xa to small-diameter prosthetic graft thrombogenicity in vivo. METHODS: Preclotted and nonpreclotted (collagen-coated) polyester grafts were studied before and 24 hours after implantation into pig femoral arteries. After incubation of explanted grafts was performed with plasma depleted of vitamin K-dependent coagulation factors by barium chloride adsorption (Ba-plasma), graft-associated thrombin activity was determined by radioimmunoassay for fibrinopeptide A. Fibrinopeptide A levels reflect thrombin-mediated fibrin formation. Factor Xa activity was characterized by measuring activation of prothrombin added to Ba-plasma. RESULTS: Thrombin and factor Xa were associated with the luminal surfaces of preclotted grafts before and 24 hours after implantation. Nonpreclotted grafts had negligible procoagulant activity before implantation. After 24 hours in vivo graft-associated factor Xa activity was similar in both nonpreclotted and preclotted grafts; however, more thrombin was bound to nonpreclotted coated grafts (p < 0.01). CONCLUSIONS: The procoagulant activity of small-diameter prosthetic grafts persists for 24 hours after implantation and is attributable not only to graft-associated thrombin but also to de novo thrombin elaboration induced by factor Xa. Moreover, graft-associated procoagulant activity is not dependent on preclotting because it develops on nonpreclotted, collagen-coated grafts as well. Treatment strategies to attenuate graft thrombosis may require the inhibition of both thrombin and factor Xa.

Adsorption↗
PubMed1996

Preincubation of Dacron grafts with recombinant tissue factor pathway inhibitor decreases their thrombogenicity in vivo.

BACKGROUND: We have previously shown that preincubation of whole blood clots with recombinants tissue factor pathway inhibitor (rTFPI) attenuates clot-associated procoagulant activity assessed ex vivo. This study was undertaken to determine whether a single local application of rTFPI induces similar attenuation of the procoagulant activity on preclotted Dacron grafts implanted in an artery in vivo. METHODS: Dacron grafts (4 mm x 4 cm long) were preclotted in porcine blood and incubated with either rTFPI (5 mg/ml) or arginine-phosphate buffer for 15 minutes. Grafts were implanted end-to-end in the femoral arteries of 10 pigs, with one rTFPI-treated and one buffer-treated graft implanted in each animal. Animals did not undergo anticoagulation either before or after graft implantation. Radiolabeled porcine fibrinogen was injected intravenously, and the grafts underwent perfusion for 1 hour. A subgroup of animals (n = 7) also had infusion of radiolabeled autologous platelets at the time of administration of radiolabeled fibrinogen. RESULTS: Fibrin(ogen) deposition was decreased in rTFPI-treated grafts by 36% +/- 7% (mean +/- SEM) compared with buffer-treated grafts (p = 0.001). Platelet deposition was also reduced in the rTFPI-treated grafts by 31% +/- 15%, although the reduction did not reach statistical significance (p = 0.10). The extent of rTFPI-mediated attenuation of fibrin(ogen) versus platelet deposition varied independently among animals. CONCLUSIONS: Clot-directed anticoagulant effects of rTFPI appear to be useful for substantially decreasing the thrombogenicity of Dacron grafts immediately after their implantation. Chronic studies to determine whether the decreases in thrombogenicity result in improved long-term graft patency appear warranted.

Animals↗
PubMed1996

Percutaneous dilational tracheostomy: report of 356 cases.

OBJECTIVE: To evaluate the procedure time, complications, and percutaneous dilational tracheostomy (PDT) charges. DESIGN: Operative data were prospectively collected for 356 PDTs including the initial series of 141 PDTs reported in 1994. Short- and long-term complications were retrospectively identified by review of medical records and patient telephone interviews. MATERIALS AND METHODS: PDT was performed using the "Ciaglia" method of serial dilation over a Seldinger guidewire. Discharged patients (n = 258) were followed for a mean (+/-SD) of 10 +/- 7 months. MEASUREMENTS AND MAIN RESULTS: The mean procedure time was 15 +/- 8 minutes; operative mortality rate, 0.3% (1/356); overall complication rate, 19% (69/356); long-term symptomatic tracheal stenosis rate, 3.7% (8/214). The mean total patient charge for bedside PDT was $1,370; for open tracheostomy in the operating room, $2,675. CONCLUSIONS: Surgeons can rapidly perform PDT at the bedside with a lower risk of complications than open tracheostomy and at a significantly reduced patient charge.

Adolescent↗
PubMed1996

Regulation of polyamine synthesis and transport by fibroblast growth factor in aortic smooth muscle cells.

Basic-FGF (FGF2) is implicated as a regulator of smooth muscle cell proliferation that develops after arterial injury. Polyamines are essential for cell growth and differentiation and may mediate some of the FGF2-elicited responses. To examine this possibility, the effect of FGF2 on polyamine synthesis and uptake was tested on rat arterial smooth muscle cells. Exposure of cells to FGF2 for 24 and 48 h resulted in increased intracellular polyamine content. Ornithine decarboxylase (ODC) activity increased in FGF2-treated cells after 6 h of treatment, whereas no increases were detected in ODC mRNA steady-state levels. Basic-FGF increased maximal polyamine transport rate without changes in Km. Treatment with actinomycin D decreased polyamine transport. The effect of cyclohexamide on polyamine uptake was dose dependent. These studies indicate that treatment of vascular smooth muscle cells with FGF2 results in increases in intracellular polyamine content, polyamine synthetic activity, and polyamine transport.

Animals↗
PubMed1995

Biliary sludging in critically ill trauma patients.

We used serial weekly ultrasonography to prospectively screen 19 critically ill trauma victims for the development of biliary sludge. Fourteen patients had sludge formation during their hospitalization. Sludge development was positively associated with increased transfusion requirements, but not with any other laboratory or clinical findings, including injury severity scores. The enteral feedings administered to most patients did not prevent sludge formation in the majority of cases; all five patients receiving total parenteral nutrition had sludge. Three patients had complications that could possibly be attributed to the sludge (one case of acalculous cholecystitis and two cases of mild pancreatitis). No such problems occurred in the five patients who did not have sludge. No long-term clinical problems related to sludge have occurred. We conclude that gallbladder sludge frequently develops in critically ill trauma patients and that sludge may be associated with pancreatobiliary complications.

Adolescent↗
PubMed1995

The ramifications of immediate reconstruction in the management of breast cancer.

A retrospective review of 50 patients who underwent immediate postmastectomy breast reconstruction was performed to determine the effect of reconstruction on the treatment of these patients. The overall complication rate was 50% (25 of 50). Smoking statistically correlated with an increased rate of wound complications (0 = 0.0001). Obese patients had nearly twice as many wound complications; however, this finding was not statistically significant (P = 0.261). Eleven of the 50 patients underwent reconstruction with a prosthesis, with an overall complication rate of 64% (seven of 11) and a 55% (six of 11) rate of prosthesis loss. Thirty-nine of the 50 patients underwent reconstruction with autologous tissue. Forty-six per cent (18 of 39) of the patients in the autologous group developed complications, and eight required emergent reoperation to prevent flap loss. The wound complication rate was significantly lower for bipedicled transverse rectus abdominis muscle (TRAM) flap reconstructions than for other forms of autologous reconstruction (P = 0.040). total operative time (including mastectomy) was 3.11 hours (range, 2-4 hours) for the prosthetic group and 9.4 hours (range, 5-15 hours) for the autologous group. All but two patients undergoing autologous tissue reconstruction required blood transfusions; an average of 2.4 U of blood was transfused per patient (range, 0-7 U). Only two patients in the prosthetic group required a transfusion. The average hospital stay was 5 days (range, 2-7 days) for the prosthetic group and 8.3 days (range, 5-19 days) for the autologous tissue group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Characterization of polyamine transport in rat aortic smooth muscle cells.

Increased arterial wall polyamine content has been linked to intimal hyperplasia (IH) formation. Intracellular polyamine content may be regulated by a polyamine transmembrane transport mechanism, but the existence of such a system has not been demonstrated in systemic arterial smooth muscle cells. This study characterizes polyamine transport as found in rat aortic smooth muscle cells. Smooth muscle cells were isolated and cultured from Sprague-Dawley rat aortas. Polyamine transport was determined by adding [14C]-polyamines to the medium, calculating transport kinetic parameters, Vmax and Km. Competition studies with unlabeled polyamines and uptake in the presence of paraquat, a polyamine transport inhibitor, were done to test the specificity of the uptake system. We identified polyamine transporters in aortic smooth muscle cells which were temperature, concentration, and time dependent. Kinetic studies revealed that spermidine and spermine had greater affinity for the transporter(s) than putrescine (Km = 0.3, 0.3, and 3.7 microM respectively; P = 0.0001) while maximum uptake velocity was similar for all polyamines (26.6-31.0 pmole/mg protein/min). Inhibition of de novo polyamine synthesis upregulated polyamine transport 2.8-3.8 times (P = 0.0001) while transporter affinity (as reflected by Km) remained unchanged. Competition studies and paraquat treatment indicated the presence of two polyamine transporters: one shared by all polyamines, the other specific for spermine and spermidine. These data indicate that transmembrane polyamine transport occurs in arterial smooth muscle cells. Upregulation of this system may represent one control mechanism for IH development.

Animals↗
PubMed1994

Percutaneous dilational tracheostomy: report of 141 cases.

Tracheostomy is indicated frequently in the treatment of critically ill patients who require prolonged mechanical ventilation. The purpose of this prospective study was to evaluate our initial experience with 141 cases of percutaneous dilational tracheostomy (PDT) performed over a 2-year period. One hundred twenty PDTs (85%) were placed at the bedside, and 21 (15%) were performed in the operating room in conjunction with other procedures. The procedural complication rate was 11% (16 of 141). Most complications were easily recognized and did not preclude the completion of PDT. One death occurred secondary to severe bronchospasm. The postoperative complication rate was 8% (11 of 141). The most frequent complication was peristomal oozing. The average duration of follow-up after decannulation for patients discharged alive and decannulated was 36 +/- 27 weeks. There were 3 recognized cases of clinically symptomatic tracheal stenosis. We conclude that PDT is comparable with the open method and can be performed rapidly and safely at the patient's bedside.

Adolescent↗
PubMed1994

Percutaneous dilational tracheostomy in children and teenagers.

Percutaneous dilational tracheostomy (PDT) is a new technique that has been successfully performed in adult patients who required long-term mechanical ventilation, but it has not been used in children. The authors report their initial experience with PDT in 11 children and teenagers. The procedure is as follows. Using Seldinger's technique, the trachea is cannulated with a guide-wire. It is then progressively dilated, to an appropriately sized tract, with dilators from a commercially available kit. Then, a tracheostomy tube can be inserted into the trachea, loaded over a dilator. Eleven children, aged 10 to 20 years, underwent PDT in an average of 20 minutes. In eight cases, PDT was performed at the bedside. One intraoperative and one postoperative complication developed in the same patient; both complications were easily recognized and treated. Tracheal stenosis has not developed in eight decannulated patients at an average of 43 +/- 30 weeks after decannulation. PDT appears to be a safe, potentially cost-effective alternative to open tracheostomy in young patients.

Adolescent↗
PubMed1994

Mirizzi's syndrome.

Mirizzi's syndrome is a partial obstruction of the biliary tree caused by a stone impacted in the cystic duct, with or without development of a cholecysto-biliary fistula. We report our experience with five cases and review current methods of diagnosis and management. Preoperative diagnosis greatly facilitates management. Diagnosis may require a combination of ultrasonography, computed tomography, and cholangiography (percutaneous or endoscopic retrograde). At surgery, dissection in the triangle of Calot should be minimized to avoid injury to the common bile duct. Often, a partial cholecystectomy is the only safe option. Defects in the common bile duct can be repaired by a variety of methods. The morbidity and mortality associated with this rare syndrome can be relatively high. A number of patients may have late biliary strictures.

Abdomen↗
PubMed1993

Traumatic ventral abdominal hernia associated with small bowel gangrene: case report.

A rare case is presented of traumatic subcutaneous rupture of the rectus abdominis with ventral herniation and decollement of the jejunum and transverse colon. Irreversible ischemia of the small bowel had occurred following a large mesenteric avulsion. Computed tomographic scanning detected the parietal defect and identified the herniating viscera.

Abdominal Muscles↗
PubMed1993

Coexisting hyperthyroidism and primary hyperparathyroidism.

The simultaneous occurrence of hyperthyroidism and primary hyperparathyroidism is rare in the absence of previous neck irradiation. We report two cases from our institution. Hypercalcemia secondary to hyperthyroidism is common and may obfuscate the diagnosis of concomitant primary hyperparathyroidism. Therefore the continued presence of hypercalcemia in a patient with successfully treated hyperthyroidism should lead the physician to search for primary hyperparathyroidism. Treatment of these concomitant disease processes consists of combined thyroidectomy and parathyroidectomy.

Adult↗