Intravascular Stenting of Acute Experimental Type B Dissections
Stanford University, Palo Alto, California, United States Journal of Surgical Research
(Impact Factor: 1.94).
05/1993; 54(4):381-8. DOI: 10.1006/jsre.1993.1061
To evaluate the efficacy of intravascular stenting for acute aortic dissection, 12 dogs underwent surgical creation of an acute type B dissection. Intravascular ultrasound evaluated luminal diameter, distal propagation, and branch involvement. Three animals underwent no further treatment (control). In 9 dogs, balloon-expandable intravascular stents (15-20 mm) were placed proximally to compress the intimal flap. One dog with a small dissection had complete obliteration of the false lumen after initial stent placement. Six dogs with extension below the diaphragm were initially stented proximally to restore flow; 3 were left with a residual distal false lumen, while 3 had additional stents placed to obliterate their entire false lumen. In the final 2 dogs, proximal stenting resulted only in partial compression of the false lumen. Two animals died within 24 hr due to prolonged hemodynamic instability and aortic rupture at the intimal flap, respectively. Six weeks later, radiologic and histologic evaluation was performed on the 10 surviving animals. All stented true lumens were patent without thrombus formation, and stents were covered by neointima. In dogs with stenting of the entire dissection, the aortic wall had healed and no false lumen was present. However, in all dogs with only proximal obliteration, 1/2 with partial compression, and 2/3 controls, a patent false channel was present indicative of a chronic dissection. Thus, we found that intravascular stents can restore true lumen flow and obliterate the false lumen in experimental dissections; however, stenting limited to the proximal dissection does not prevent formation of a chronic residual patent false lumen.
Available from: nih.gov
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ABSTRACT: The authors describe the initial clinical experience with a new device, approved by the FDA for investigation, for repair of abdominal aortic aneurysm by transfemoral endovascular insertion of an aortic graft.
Sixty-nine patients with abdominal aortic aneurysms were screened, and ten were found to be suitable for endovascular grafting. Repair was done in the operating room using general anesthesia. One femoral artery was surgically exposed, and the device, containing a premeasured graft with proximal and distal self-expanding fixation devices, was inserted with fluoroscopic control through an open arteriotomy.
Eight of ten patients underwent successful graft placement, and two patients required conversion to an open repair. On follow-up, six of eight patients who underwent graft placement functioned normally, with documented aneurysm thrombosis. Two patients who underwent graft placement functioned normally, with contrast computed tomography evidence of incomplete aneurysm thrombosis, but without further expansion.
Transfemoral repair is safe and appears to be effective. Phase II study currently is appropriate, with need for long-term follow-up.
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ABSTRACT: To evaluate obliteration of an experimental aortic dissection with a balloon-expandable intravascular stent.
Fourteen adult dogs were divided into two groups. In group 1 (n = 6), a thoracoabdominal aortic dissection was surgically created to observe the natural course of this lesion. In group 2 (n = 8), a balloon-expandable intraluminal vascular graft was introduced via the femoral artery in a dissected aorta to try to obliterate the dissection. Angiography was performed postoperatively and again 6 weeks later before the aortae were explanted for pathologic evaluation.
In group 1, postoperative aortography depicted evidence of aortic dissection in all animals. Autopsy revealed persisting dissection with reentry tear near the celiac axis in five animals. In group 2, placement of a stent at only entry and reentry sites resulted in partial obliteration of the dissection (n = 3). When the entire length of dissected aorta was treated, the dissection was completely obliterated (n = 4).
An aortic dissection can be obliterated with a balloon-expandable stent if the entire dissected aorta is treated.
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ABSTRACT: The aim of this study was to evaluate the accuracy of information obtained with a prototype intravascular ultrasound (IVUS) system in chronic aortic dissection by comparing results with angiography, transesophageal echocardiography (TEE), computed tomography, or magnetic resonance imaging. We assigned 15 patients to IVUS imaging after they underwent angiography. The detection rate of the intimal flap was 100% in all segments of the aorta, and the detection rate of the intimal tear was 0%, 50%, 50%, and 77.8% in the ascending, arch, descending, and abdominal aorta, respectively. IVUS demonstrated 100% of the celiac and renal arteries, and 80% of the superior mesenteric arteries as well as their relation to dissection. It clarified the origin of 12 of 60 main abdominal branches (20%) which were not clear on the angiogram. It also determined the distal extent of the dissection in all cases. With regard to the size of the vessel, there was a good correlation between IVUS and computed tomographic values (r = 0.98, p < 0.01). No complications occurred in any patient. IVUS accurately demonstrated thrombus or spontaneous echo contrast in the false lumen that was confirmed with computed tomography or TEE, or both. It was especially useful in evaluating the abdominal aorta with regard to determining the size of the vessel, the extent of dissection, the relation of the branches to the false lumen, and the detection of intimal tears--important information for follow-up of patients and for planning surgery.(ABSTRACT TRUNCATED AT 250 WORDS)
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