Biomedical subjects
Publications and source records attributed to R K Kerlan.
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The relative merits of aortomonoiliac and bifurcated stent-graft configurations depend on the patient's arterial anatomy and clinical status. Aortomonoiliac stent-grafts are simple to make, simple to insert, and versatile. They are most useful when the iliac artery anatomy is severely distorted and the patient is old, sick, and inactive. The main problems with this approach are all consequences of femorofemoral bypass. The bifurcated stent-graft is the preferred alternative in healthy patients, because it ensures flow to both common iliac arteries, thereby eliminating the need for femorofemoral bypass. However, bifurcated stent-grafts and their delivery systems are difficult to make and difficult to deploy, especially when the iliac anatomy is distorted or emergency circumstances preclude preoperative sizing. This article addresses the advantages and disadvantages of the aortomonoiliac graft.
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Solitary fibrous tumors of the pleura are rare. Approximately 600 cases have been described in the literature. We report a case of a young man with a giant solitary fibrous tumor of the pleura that filled his entire left hemithorax and anterior mediastinum and extended into the right side of his chest. The diagnostic modalities employed, the operation, and the postoperative management resulting in complete resection of the tumor and full lung reexpansion are described.
The standard techniques of endovascular aneurysm repair sometimes fail to produce atraumatic stent-graft delivery of hemostatic implantation, and additional maneuvers are required to avoid conversion to open repair. Between June 1996 and May 1997 elective endovascular aneurysm repair was performed in 33 high risk patients, using a Z-stent-based prosthesis. Challenging anatomic features included: short neck (< 15 mm) in four cases, angulated neck (> 60 degrees) in seven, iliac aneurysm in six, and iliac tortuosity (> 80 degrees) in 24. There were no deaths, no renal failure, no pulmonary failure, no graft thrombosis, no migration, and no conversions to open surgery. Deviations from standard technique were required to treat iliac artery dissection, iliac artery stenosis, and leaks resulting from proximal stent malalignment, proximal stent malposition, and distal stent malposition. The necessary adjunctive maneuvers included: additional stent placement, additional stent-graft placement, and balloon dilatation. Mean operating time was 191 +/- 72 min, mean contrast volume was 148 +/- 76 ml, and mean blood loss was 314 +/- 427 ml. Mean time from operation to discharge from the hospital was 3.5 +/- 1.67 days. These short-term results demonstrate that endovascular aneurysm repair is safe and effective in high risk patients, only if adjunctive maneuvers are available to supplement standard technique.
Expandable metallic stents offer advantages over previously available techniques for treating benign tracheobronchial stenosis or obstruction. Endoluminal stent placement offers a rapid and effective means of opening up narrowed airways, and results in excellent relief of symptoms and improvement in pulmonary function. Because they are delivered in a nonexpanded state using flexible over-wire systems, they can be placed using a flexible bronchoscope and can be located in second-order bronchial branches. Metallic stents have been used to treat benign airway obstruction caused by anastomotic narrowing after lung transplantation, infection, congenital lesions, tracheobronchial malacia, inflammatory conditions including relapsing polychondritis, Wegener granulomatosis, and acquired immunodeficiency syndrome, and external compression from benign mediastinal masses or fibrosis. The stents become epithelialized, which prevents migration and permits ciliary activity to continue. Significant complications can occur, including airway inflammation, stent migration, airway erosion, and stent fracture and collapse, but more serious complications are uncommon. Computed tomography is essential in imaging patients being considered for stent placement, as it allows 1) accurate representation of airway anatomy in three dimensions. 2) measurement of airway diameter, 3) evaluation of airway anatomy distal to a narrowed segment and invisible to bronchoscopy, 4) demonstration of dynamic changes in airway morphologic features during forced exhalation in patients with airway malacia, and 5) demonstration of focal or diffuse air trapping in lung peripheral to the abnormal airway. In patients who have had stent placement, computed tomography is valuable in assessing airway morphologic features and dynamics distal to the stent, and can be valuable in assessing stent dysfunction.
PURPOSE: To analyze the outcome of percutaneous antegrade ureteral stent placement for treatment of ureteral stenoses and leaks after renal transplantation. MATERIALS AND METHODS: Antegrade pyelography and percutaneous ureteral stent placement were performed in 45 patients with ureteral obstruction (n = 40), leak (n = 3), or both (n = 2). Obstructions were graded as mild, moderate, or complete, and as early (< or = 3 months after transplantation) or late (> 3 months). RESULTS: The outcome of stent placement was successful in 25 (57%) patients (average follow-up, 30 months). The ureteroneocystostomy (UNC) was the most common site of obstructions (22 of 41), leaks (four of five), and successful outcomes (16 of 22). Moderate obstructions were most common (29 of 41) and responded best to treatment (17 of 29). Eighteen (69%) of 26 early obstructions and five (33%) of 15 late obstructions were successfully managed percutaneously. All complications (12 of 45 patients) were minor, with infections the most common (n = 7). No mortality or allograft loss was attributable to stent placement. CONCLUSION: Ureteral stents are safe and effective for the treatment of obstructions and leaks and are particularly effective for early and UNC obstructions. These stents may also be useful for temporary drainage.
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Stenosis of vessels proximal to the renal artery is an unusual cause of allograft ischemia. We report four patients who had such 'suprarenal' arterial stenoses leading to graft dysfunction that was reversed with revascularization. We additionally review the existing literature on this entity, outline the etiologies of such stenoses, as well as discuss the surgical and non-surgical therapeutic options in patients with this uncommon cause of allograft dysfunction.
BACKGROUND: Transcatheter embolization is accepted as a safe method for treating acute bleeding from the upper gastrointestinal (GI) tract. Hesitancy persists using this technique below the ligament of Treitz, based on the belief that the risk of intestinal infarction is unacceptably high, despite mounting clinical evidence to the contrary. METHODS: A series of 17 consecutive patients with angiographically demonstrated small intestinal or colonic bleeding was retrospectively reviewed. The success and complication rate of subselective embolization was assessed. RESULTS: Bleeding was stopped in 13 of 14 patients (93%) in whom embolization was possible, and in 13 of 17 patients (76%) where there was an intention to treat. Sufficiently selective catheterization to permit embolization could not be achieved in 3 patients. No clinically apparent bowel infarctions were caused. CONCLUSION: Subselective embolization is a safe treatment option for lower GI bleeding, suitable for many patients and effective in most. Careful technique and a readiness to abandon embolization when a suitable catheter position cannot be achieved are important.
Transcatheter arterial embolization is widely used to treat life-threatening iatrogenic hemobilia, although in the transplanted liver its use has only been reported in two cases. To evaluate more fully whether transcatheter embolization is safe and effective in transplant recipients, we retrospectively reviewed eight cases of severe hemobilia. These occurred after 128 percutaneous transhepatic biliary drainage procedures performed during a 6-year period. In each case, angiography localized the bleeding to a specific intrahepatic branch that was then subselectively catheterized and occluded by transcatheter embolization. Bleeding was successfully controlled by this method in all eight patients with no immediate complications. The main, right, and left hepatic arteries were shown to be patent immediately after embolization by angiography in all patients. Duplex sonography performed in each case (1 to 4 months) after the procedure confirmed that patency was maintained in all patients. No patients developed liver abscesses, sepsis, or clinical liver infarctions after the embolization. No patients underwent retransplantation after embolization. Our experience shows that superselective transcatheter embolization is a safe, effective therapy to correct iatrogenic hemobilia in the liver transplant recipient without threatening the patency of the major hepatic arteries, the viability of the liver, or the integrity of the biliary tree.
BACKGROUND/AIMS: Transjugular intrahepatic portosystemic shunt (TIPS) is a new therapy for variceal bleeding. Immediate technical and short-term clinical results have been reported. This study was undertaken to evaluate mid-term outcome after TIPS in patients who successfully underwent the procedure for variceal bleeding. METHODS: Ninety patients were followed up prospectively by clinical examination and radiological shunt evaluation including Doppler sonography and transjugular portal venography. RESULTS: The average follow-up in surviving patients was 2.2 years. The cumulative survival rate was 60% at 1 year and 51% at 2 years. The rate of cumulative rebleeding was 26% at 1 year and 32% at 2 years. A shunt abnormality was noted in all rebleeding patients. Rebleeding was successfully controlled in all but 1 of the patients who underwent shunt revision. Cumulative detection of stenosis or occlusion was 31% at 1 year and 47% at 2 years. Thirty-eight percent of shunt abnormalities were detected by routine surveillance. Percutaneous shunt revision was attempted in 22 patients and was successful in 21 (95%). CONCLUSIONS: Although mid-term primary patency is limited in many patients by the development of a shunt stenosis or occlusion, shunt function can be maintained in most patients by careful surveillance and periodic percutaneous intervention.
The management of acute variceal hemorrhage from portal hypertension has traditionally included pharmacologic agents, mechanical compression with tamponading balloons, and endoscopic techniques including sclerotherapy and variceal banding. The role of operative portosystemic shunting has diminished in the past several years because of unpredictable postoperative morbidity from hepatic failure or encephalopathy [1-8]. Although orthotopic liver transplantation provides a unique and effective solution to these problems, it is often impractical in the emergent setting and may not be necessary if the hemorrhage can be reliably controlled by other means. The transjugular intrahepatic portosystemic shunt (TIPS) was developed to relieve portal hypertension without the mortality and morbidity of an open surgical procedure. This review summarizes the salient history, technique, and results of this procedure. The evolving role of TIPS in the management of portal hypertension, including indications, contraindications, and the durability of the procedure, is assessed.