High-efficiency endovascular gene delivery via therapeutic ultrasound.
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OBJECTIVES: We studied enhancement of local gene delivery to the arterial wall by using an endovascular catheter ultrasound (US). BACKGROUND: Ultrasound exposure is standard for enhancement of in vitro gene delivery. We postulate that in vivo endovascular applications can be safely developed. METHODS: We used a rabbit model of arterial mechanical overdilation injury. After arterial overdilation, US catheters were introduced in bilateral rabbit femoral arteries and perfused with plasmidor adenovirus-expressing blue fluorescent protein (BFP) or phosphate buffered saline. One side received endovascular US (2 MHz, 50 W/cm2, 16 min), and the contralateral artery did not. RESULTS: Relative to controls, US exposure enhanced BFP expression measured via fluorescence 12-fold for plasmid (1,502.1+/-927.3 vs. 18,053.9+/-11,612 microm2, p < 0.05) and 19-fold for adenovirus (877.1+/-577.7 vs. 17,213.15+/-3,892 microm2, p < 0.05) while increasing cell death for the adenovirus group only (26+/-5.78% vs. 13+/-2.55%, p < 0.012). CONCLUSIONS: Endovascular US enhanced vascular gene delivery and increased the efficiency of nonviral platforms to levels previously attained only by adenoviral strategies. (+info)
Completion angioscopy following carotid endarterectomy by the eversion technique or the standard longitudinal arteriotomy with patch closure.
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INTRODUCTION: Technical defects are a potential cause of peri-operative strokes following carotid endarterectomy (CEA) by either the eversion technique or the standard method of longitudinal arteriotomy with or without patch closure. AIM: A non-randomised retrospective study was undertaken to assess the value of angioscopy for the identification of technical errors following CEA and to compare those detected following eversion and standard endarterectomy with patch closure. MATERIALS AND METHODS: Intra-operative completion angioscopy was performed following 110 CEAs (56 eversion, 54 standard). Angioscopy was omitted in 5 patients because of technical problems (2) or extreme shunt dependency (3). RESULTS: Significant technical defects were identified and corrected in 10 cases (9%) and were equally distributed between the eversion and standard procedures. There was no peri-operative stroke or death in this series. CONCLUSIONS: Significant residual defects may occur after CEA by either technique. Angioscopy allows their correction peri-operatively and has the potential to reduce peri-operative stroke. (+info)
Mechanical and structural characteristics of vulnerable plaques: analysis by coronary angioscopy and intravascular ultrasound.
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OBJECTIVES: Mechanical and structural characteristics of vulnerable plaques were evaluated using coronary angioscopy and intravascular ultrasound. BACKGROUND: Mechanical stress and composition of plaques play an important role in plaque disruption. METHODS: Thirty-eight lesions in 38 patients were examined pre-interventionally. The plaques were classified as either yellow or white using coronary angioscopy. Intravascular ultrasound imaging was performed simultaneously with electrocardiographic and intracoronary pressure recordings to calculate distensibility index and stiffness beta. Moreover, the type of remodeling was classified. RESULTS: We identified 27 patients with yellow plaques and 11 patients with white plaques. Patients with yellow plaques presented acute coronary syndromes more frequently than stable angina (85% vs. 36%, p < 0.01). The distensibility index in yellow plaques was significantly greater than it was in white plaques (2.7 +/- 0.8 mm Hg(-1) vs. 0.7 +/- 0.8 mm Hg(-1), p < 0.0001), while stiffness beta for white plaques was significantly greater than it was for yellow plaques (34.9 +/- 16.3 vs. 8.7 +/- 2.7, p < 0.0001). Compensatory enlargement occurred more frequently with yellow plaques than with white plaques (56% vs. 9%, p < 0.01), while paradoxical shrinkage occurred more frequently with white plaques than it did with yellow plaques (64% vs. 4%, p < 0.001). CONCLUSIONS: Yellow plaques with an increased distensibility and a compensatory enlargement may be mechanically and structurally weak. As a result, mechanical "fatigue," caused by repetitive stretching, may lead to plaque disruption. Plaques with a high distensibility and a compensatory enlargement may be vulnerable. (+info)
Long-term results of infrainguinal arterial reconstruction with spliced veins are equal to results with non-spliced veins.
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OBJECTIVES: to determine the long term patency of spliced and non-spliced infrainguinal vein grafts. METHODS: a prospective registry of all patients undergoing infrainguinal arterial reconstruction with autogenous vein material was retrospectively interrogated. RESULTS: between October 1988 and August 2000, 515 infrainguinal arterial reconstructions were performed on 472 patients. A total of 429 bypasses were performed with uninterrupted greater saphenous vein, 86 reconstructions using spliced vein segments. There was no significant difference in primary (63% vs 57%) and primary assisted patency (81% vs 81%) of limb salvage (88% vs 91%) at 5 years. Limb salvage was not different (88% and 91% respectively). CONCLUSION the splicing of vein grafts does not compromise patency of limb salvage. (+info)
Clinical imaging of the high-risk or vulnerable atherosclerotic plaque.
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The study of atherosclerotic disease during its natural history and after therapeutic intervention will enhance our understanding of disease progression and regression and aid in selecting appropriate treatments. Several invasive and noninvasive imaging techniques are available to assess atherosclerotic vessels. Most of the standard techniques identify luminal diameter, stenosis, wall thickness, and plaque volume; however, none can characterize plaque composition and therefore identify the high-risk plaques. We will present the different imaging modalities that have been used for the direct assessment of the carotid, aortic, and coronary atherosclerotic plaques. We will review in detail the use of high-resolution, multicontrast magnetic resonance for the noninvasive imaging of vulnerable plaques and the characterization of plaques in terms of their various components (ie, lipid, fibrous, calcium, or thrombus). (+info)
The durability of endoscopic saphenous vein grafts: a 5-year observational study.
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BACKGROUND: Endoscopic saphenous vein harvest has been explored as a minimally invasive alternative to a long continuous leg incision for removal of the greater saphenous vein. The endoscopic technique uses limited incisions (2-4) with extended "skin bridges" and videoscopic equipment for the dissection and removal of the greater saphenous vein. This study was undertaken to evaluate the long-term durability of saphenous vein grafts harvested by an endoscopic technique and used for lower extremity arterial revascularization. METHODS: All patients who underwent endoscopic saphenous vein harvesting for lower extremity arterial bypass grafting were prospectively followed for graft patency and risk factors. Grafts were surveyed with serial duplex scans at 3- to 6-month intervals over this 5-year study. Life-table methods were used to assess graft survival. A computerized registry and medical records were reviewed to determine graft patency and patient survival. RESULTS: From September 1994 to August 2000, 164 lower extremity arterial saphenous vein grafts harvested by an endoscopic technique were used for lower extremity arterial bypass grafting in 150 patients. The patient population included 111 males (75%) and 112 smokers (75%), but also included a high-risk cohort of 65 diabetic patients (43%) and 15 patients undergoing dialysis/renal transplant (10%). Twenty-eight patients (19%) died within the study period. With life-table methods, 1-, 3-, and 5-year secondary patency rates were 85% (+/- 3.2%), 74% (+/- 5.7%), and 68% (+/- 11.6%). Of the 30 failed grafts, 7 (4%) failed in the first month related to inadequate runoff (4), cardiac instability (2), and an additional surgical procedure (1). Twenty-three grafts (14%) failed between 1 and 42 months. Twenty-two (16%) of these 134 patent grafts underwent a second procedure to maintain patency (13 as primary-assisted patency and 9 as secondary patency). CONCLUSIONS: Endoscopic saphenous vein harvest for lower extremity arterial reconstruction provides a satisfactory conduit for lower extremity bypass grafting. Although increased manipulation from this limited access technique may incite an injury response in the vein, these vein grafts can maintain an adequate patency for lower extremity bypass grafting. (+info)
Endovascular repair of para-anastomotic aneurysms of the aorta and iliac arteries: preferred treatment for a complex problem.
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PURPOSE: Standard surgical repair of para-anastamotic aneurysms (PAAs) of the abdominal and thoracic aorta and the iliac arteries has been associated with high morbidity and mortality rates. We reviewed our continuing experience with endovascular repair of these lesions to determine whether this approach is favorable and durable. METHODS: All patients with PAAs of the aorta or iliac arteries who underwent endovascular treatment of their lesions between August 1993 and July 1999 were prospectively followed up, and data on age, previous aortic pathology and surgery, size of PAA, time to diagnosis, and symptoms at presentation were recorded. Preoperative, intraoperative, and postoperative imaging studies were analyzed. All patients had endovascular stent-grafts placed under digital fluoroscopic guidance in the operating room. Data on intraoperative and postoperative complications, mortality, and endoleaks were reviewed. RESULTS: From August 1993 to July 1999, 28 patients (20 men, 8 women) had 35 PAAs of the aorta or iliac arteries. There were 5 thoracic aortic, 12 abdominal aortic, and 18 iliac artery PAAs. Three patients had a contained rupture of their PAA. All patients who had originally undergone reconstruction for occlusive disease had lesions consistent with false aneurysms, whereas 73% of the aortic or iliac PAAs in patients originally treated for aneurysm disease appeared to be true aneurysms. Thirty-four of 35 PAAs were successfully excluded with stent-grafts (97%). There was one death at 30 days (3.6%) in a patient who was successfully treated endovascularly for a contained rupture of a thoracic PAA. There were four major postoperative complications (14.2%) in the 28 patients who were treated. One patient had continued perfusion of a thoracic aortic PAA (type I endoleak). The in-hospital length of stay after endovascular repair of PAA was 4 days (range, 1-18 days). The mean follow-up period was 21 months (range, 1-68 months). CONCLUSION: Endovascular repair of aortic and iliac artery PAAs is technically feasible and provides a high rate of lesion exclusion. Morbidity and mortality rates appear lower than those reported for open surgical repair. These patients can typically be discharged by the second postoperative day. Endovascular therapy for stable ruptured PAAs can be successfully performed and should be considered as an option only when appropriate devices and expertise are available. For uncomplicated PAAs of the aorta and iliac arteries, endovascular therapy may be more favorable than surgical repair. (+info)
Transluminal imaging with perspective volume rendering of computed tomographic angiography for the delineation of cerebral aneurysms.
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Transluminal imaging with perspective volume rendering of computed tomographic angiography was used to investigate three patients with unruptured cerebral aneurysms. Selective changes in the opacity chart of computed tomography values, based on a spiked peak curve, represented the contour of the vessel and aneurysmal walls as a series of rings, and allowed a transluminal view from outside or inside the vessel lumen through the spaces between the rings. This imaging technique provided direct visualization of the underlying structures and an extensive perspective view of the cerebral aneurysms, including the parent arteries and surrounding bony structures, through the overlying vessel and aneurysmal walls. Transluminal imaging may be a useful method for the extra- and intraluminal diagnosis of a cerebral aneurysm, and for simulation of the interventional and surgical procedures considered for cerebral aneurysms. (+info)