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Purpose: To evaluate the feasibility of a percutaneously created type-B aortic dissection as an experimental model for percutaneous therapy. This model was used to evaluate the hemodynamic effects of single-balloon fenestration of the intimal flap., Materials and Methods: Acute type-B dissections were created in descending aortae of 15 swine via a femoral (n = 6) or carotid (n = 9) approach. The initial subintimal tear was made with use of a Colapinto needle. The dissections were extended to a predefined position in the aorta. The proximal and distal tears were balloon dilated. The mural flap was balloon fenestrated in six animals, just above the celiac artery. Aortograms were obtained to establish the presence and extent of the dissection. Manometry was performed in both lumina to evaluate the hemodynamics of the dissected aorta and the effects of balloon fenestration in this model. Pathologic specimens were also examined., Results: Creation of dissection was successful in 11 of 15 animals, with six developing true lumen narrowing (group A). The other five animals (group B) had flow in both lumina without evidence of true lumen narrowing. After the creation of a single-balloon fenestration in the group A swine, the arteriograms revealed no evidence of blood admixture between the true and false lumina, and there was no change in the intravascular pressures. Examination of the explanted aortae showed a more extensive circumferential dissection in group A animals as compared with group B., Conclusion: The percutaneously created acute type-B aortic dissection is a feasible model for experimentation. The hemodynamics of the aorta did not change after single-balloon fenestration in this model.

Purpose: To compare pulse-spray to continuous-infusion thrombolysis with high-dose urokinase in thrombosed dialysis access grafts., Methods: A prospective randomized controlled trial was performed. From August 1992 to September 1993, 30 thrombosed polytetrafluoroethylene (PTFE) grafts in 24 patients were included, 15 grafts in each group. The success of thrombolysis, mean time to thrombolysis, mean urokinase dose, and 60-day patency rate were evaluated., Results: In the pulse-spray group, the mean time to thrombolysis was 72 min with a mean urokinase dose of 560,000 U. The 60-day patency rate was 71%. In the continuous-infusion group, the mean infusion time to thrombolysis was 55 min with a mean dose of 479,000 U. The 60-day patency rate was 73%., Conclusion: No statistically significant difference was found between the two techniques in the mean time to thrombolysis, the mean urokinase dose used, or the 60-day patency rate.

Purpose: The authors describe their experience with the use of single-piece, tapered stent-grafts for the treatment of abdominal aortic or aortoiliac aneurysms., Materials and Methods: Single-piece, tapered stent-grafts were placed in 15 patients for the treatment of abdominal aortic aneurysms with small distal necks (n = 13), and aortoiliac aneurysms (n = 2). There were 13 men and two women who ranged in age from 59 to 83 years (mean, 71 years). Usual open surgery was considered high risk in all patients because of comorbid medical conditions. The stent-grafts were made of Z stents covered with polytetrafluoroethylene (PTFE). Additional stent-grafts needed to treat perigraft leaks were made of Z stents covered with woven polyester (n = 5), Wallstents covered with PTFE (n = 2), Z stents covered with PTFE (n = 1), and a PTFE-covered Palmaz stent (n = 1). After stent-graft placement, the contralateral iliac artery was occluded by a blocking device composed of either a PTFE-covered Palmaz (n = 1) or Z stent (n = 13), and a femoral-femoral bypass was created., Results: After placement of the stent-grafts, immediate perigraft leaks were observed in eight patients (53%). These were at the proximal (n = 5) or the distal end (n = 3). All, except one, were treated successfully with additional stent-grafts. The one failure was in a patient who developed aortic rupture after balloon dilation, requiring open surgical repair. Second procedures were required in four patients (27%), including three leaks treated successfully with coil embolization and/or a back-up stent-graft, and one stent-graft migration and thrombosis treated by thrombolysis and placement of an additional stent-graft. One patient died of respiratory failure 23 days after placement of the stent-graft. The mean follow-up was 12 months (range, 4-26 months). On the last follow-up, the aneurysms in the 13 living patients remained thrombosed., Conclusion: Treatment of aortoiliac aneurysms with use of single-piece, tapered stent-grafts is feasible in selected patients. The morbidity and mortality rates compare favorably with those of the open surgical procedures in a high-risk population. Further improvements in the technique and longer follow-up data are needed before this procedure can be recommended for the treatment of all aortoiliac aneurysms.

Purpose: To evaluate use of catheter-directed thrombolysis and/or endovascular stent placement to treat superior vena cava (SVC) syndrome., Materials and Methods: Fifty-nine consecutive patients with SVC syndrome were studied. The cause was underlying malignancy in 43 and benign disease in 16. All patients underwent bilateral upper-extremity venography. The SVC was occluded in 31 cases and stenosed in 28. Twenty-seven patients underwent catheter-directed thrombolysis; 51 underwent endovascular stent placement. Patency was defined in terms of absence of symptoms and signs of SVC syndrome., Results: Technical success was achieved in 56 of 59 patients (95%). Among 42 patients with underlying malignancy (mean follow-up, 7.0 months; range, 1-34 months), primary clinical patency was achieved in 33 (79%) and secondary clinical patency was achieved in 39 (93%). Among 13 patients with benign disease (mean follow-up, 17.0 months; range, 1-27 months), primary clinical patency was achieved in 10 (77%) and secondary clinical patency was achieved in 11 (85%). Four patients were lost to follow-up. Periprocedural mortality and morbidity rates were 3% (two of 59 patients) and 10% (six of 59 patients), respectively., Conclusion: Catheter-directed thrombolysis and endovascular stent placement is a safe and effective treatment for SVC syndrome.

Purpose: Standard therapy of mycotic aneurysms in the descending aorta consists of thoracotomy and in situ graft placement or extraanatomic bypass. The alternative use of endovascular stent-grafts was evaluated for management of infected aneurysms of the thoracic aorta., Materials and Methods: In a retrospective analysis during a 5-year period, 112 patients underwent stent-graft placement for thoracic aortic aneurysms. Three patients (mean age, 68.6; range, 64-70 years) had mycotic thoracic aneurysms. Stent-grafts were constructed from Z stents covered with polyester fabric and were delivered remotely through a catheter under fluoroscopic guidance., Results: Complete thrombosis of the mycotic aneurysms was achieved in all patients. One patient required a second separate stent-graft placement procedure because of migration of the initial device; the second patient underwent surgical repair of a ruptured mycotic abdominal aortic aneurysm followed immediately by stent-graft placement for a chronic mycotic thoracic aneurysm; a third patient underwent repair of two infected false aneurysms secondary to complete rupture of a surgical interposition graft. There were no complications of persistent bacteremia despite placement of the stent-graft device at the site of primary infection, reinfection, delayed rupture, paraplegia, distal emboli, or surgical conversion. One patient died of cardiac arrest at 25 months; there were no perioperative deaths (< or = 30 days). The remaining two patients were alive and well at median follow-up of 24 months (range, 4-25 months)., Conclusion: Endovascular stent-grafts combined with antibiotic therapy may be an alternative to conventional thoracotomy in managing mycotic aneurysms of the descending thoracic aorta.

Purpose: To demonstrate the feasibility and safety of endovascular stent-graft placement for treatment of traumatic aortic aneurysm., Materials and Methods: Ten patients with traumatic aortic aneurysm were treated with endovascular stent-grafts. Three patients had an acute traumatic aneurysm; seven had a chronic aneurysm. Stent-grafts were constructed from modified Z-stents covered with woven polyester or expanded polytetrafluoroethylene graft material and were deployed through a 20-24-F delivery sheath in an exposed artery located remotely from the lesion., Results: Stent-graft placement and thrombosis of the aneurysmal sac were successful in all patients. Major complications were encountered in three patients after endovascular treatment. One patient had a peri-graft leak; complete thrombosis of the aneurysmal sac was achieved after coil embolization of the leak. Transposition of the left subclavian artery was necessary to relieve left arm ischemia in another patient. In the third patient, stent placement in the left main stem bronchus was needed to relieve left lung atelectasis. All patients were alive and without complications during the follow-up period (mean, 15 months)., Conclusion: Transluminal placement of endovascular stent-grafts is a technically feasible method for treatment of traumatic thoracic aortic aneurysm and may be an effective alternative to open-chest surgery.

Purpose: To evaluate the feasibility of stent-grafts for treatment of isolated iliac artery aneurysms (IAAs)., Materials and Methods: Nine IAAs in eight patients were treated with transluminally placed endovascular stent-grafts. All patients were men (median age, 72 years). In three, the aneurysm involved both the common and internal iliac arteries. In one, common and external iliac arteries were involved. The other aneurysms involved only the common iliac artery. Two aneurysms were treated with balloon-expandable stents covered with polytetrafluoroethylene (PTFE) graft material, three were treated with self-expanding Z-stents covered with a woven polyester graft, and four were treated with self-expanding Z-stents covered with PTFE., Results: Transluminal placement of the stents was successful in all patients with thrombosis of the aneurysms. There were no distal thromboembolic events, deaths, or infections. The median follow-up period was 8.5 months., Conclusion: Initial results suggest that transluminal stent-graft placement for treating isolated IAAs is a safe and effective alternative to surgery in selected patients. Long-term follow-up data are needed before this approach can be recommended for the primary treatment of IAAs.

Although carcinoma of the gallbladder has a low overall prevalence, it is the most common malignant tumor of the biliary tract. Retrospectively, 59 cases of histologically proved gallbladder carcinoma were reviewed. The series consisted of 42 women and 17 men, ranging in age from 35 to 86 years. Clinical manifestations of gallbladder carcinoma include right upper quadrant pain, anorexia, weight loss, and jaundice. Radiologic findings included focal or diffuse thickening of the gallbladder wall (49%), a mass in the gallbladder fossa (37%), and an intraluminal mass (14%). Associated findings were cholelithiasis (64%), biliary duct dilatation (38%), invasion of the adjacent structures (67%), distant metastases other than those of the liver (3%), and porcelain gallbladder (4%). The histologic diagnoses were adenocarcinoma (90%) and squamous cell carcinoma (10%). Differential diagnoses include all conditions in which the gallbladder wall appears thickened. A general awareness of the radiologic features of gallbladder carcinoma enhances preoperative diagnoses.

Background: The clinical staging and management of both primary and metastatic lung lesions depends on accurate imaging techniques. Biochemical imaging with positron emission tomography, (PET), and the glucose analog 2-[18F]-fluoro-2-deoxy-D-glucose, (FDG), complements anatomic imaging with conventional radiologic methods., Methods: A new "whole-body" PET FDG technique that produces two-dimensional, nontomographic and tomographic longitudinal images of the entire body has been developed at UCLA. Sixteen patients with known pulmonary nodules who had undergone thoracic computed tomography (CT) were studied with whole-body PET FDG imaging at the UCLA Medical Center., Results: This PET FDG imaging method identified metabolically active tumor foci in all eight patients with bronchogenic carcinomas, four patients with metastatic lesions to the thorax, and two patients with Hodgkin disease. All diagnoses were confirmed histologically. Additionally, the PET FDG technique detected extrathoracic metastases in 4 of 16 patients. Thoracic CT was not diagnostic of neoplasm in two of the eight patients with bronchogenic carcinomas. In one patient with an ACTH-producing bronchial carcinoid, the lesion ultimately was detected on high-resolution CT but was not metabolically active on PET FDG imaging., Conclusions: This is the first report of whole-body PET FDG imaging in patients with thoracic lesions. PET FDG imaging accurately detected metabolically active tumor (both intrathoracic and extrathoracic) in patients with bronchogenic carcinoma, pulmonary metastatic disease, and Hodgkin lymphoma. Because lung cancer is characteristically a multisystem disease, this whole-body PET FDG technique has significant implications for treatment planning.

Mouse hepatitis virus (MHV), a murine coronavirus, replicates in the cytoplasm and synthesizes 7 viral mRNAs containing an identical stretch of leader RNA sequences at the 5'-end of each RNA. The leader-coding sequences at the 5'-end of genomic RNA are at least 72 nucleotides in length and are joined to the viral mRNAs by a unique mechanism. Utilizing a leader-specific cDNA probe, we have detected several free leader RNA species ranging from 70 to 82 nucleotides in length. The predominant leader RNA was approximately 75 nucleotides. In addition, larger distinct leader-containing RNAs were also detected ranging from 130 to 250 nucleotides in length. The 70-82-nucleotide leader-related RNAs were present in both the cytosol and membrane fractions of infected cells. They were also detected only in the small RNA fractions but not associated with the replicative-intermediate RNA. These data suggest that the leader RNAs were associated with the membrane-bound transcription complex but at least part of them were dissociated from the RNA template. We have also identified a temperature-sensitive mutant, which synthesizes only leader RNA but not mRNAs at nonpermissive temperature, indicating that leader RNA synthesis is distinct from the transcription of mRNAs. These data support the leader-primed mechanism for coronavirus transcription and suggest that one or more free leader RNAs are used as primers of mRNA synthesis.