Juan C. Parodi

Transfemoral Intraluminal Graft Implantation for Abdominal Aortic Aneurysms

This study reports on animal experimentation and initial clinical trials exploring the feasibility of exclusion of an abdominal aortic aneurysm by placement of an intraluminal, stent-anchored, Dacron prosthetic graft using retrograde cannulation of the common femoral artery under local or regional anesthesia. Experiments showed that when a balloon-expandable stent was sutured to the partially overlapping ends of a tubular, knitted Dacron graft, friction seals were created which fixed the ends of the graft to the vessel wall. This excludes the aneurysm from circulation and allows normal flow through the graft lumen. Initial treatment in five patients with serious co-morbidities is described. Each patient had an individually tailored balloon diameter and diameter and length of their Dacron graft. Standard stents were used and the diameter of the stent-graft was determined by sonography, computed tomography, and arteriography. In three of them a cephalic stent was used without a distal stent. In two other patients both ends of the Dacron tubular stent were attached to stents using a one-third stent overlap. In these latter two, once the proximal neck of the aneurysm was reached, the sheath was withdrawn and the cephalic balloon inflated with a saline/contrast solution. The catheter was gently removed caudally towards the arterial entry site in the groin to keep tension on the graft, and the second balloon inflated so as to deploy the second stent. Four of the five patients had heparin reversal at the end of the procedure. We are encouraged by this early experience, but believe that further developments and more clinical trials are needed before this technique becomes widely used.

Endovascular repair of abdominal aortic aneurysms and other arterial lesions

The diagnosis of abdominal aortic aneurysm (AAA) has been established with increasing frequency during the past two decades. Although AAA may cause distal embolization, rupture remains the most common and deadly complication. For nearly 40 years, elective replacement with a synthetic graft has proved to be the most appropriate method to prevent AAA rupture, and it has been associated with a postoperative mortality rate of less than 5% at most medical centers. Nonfatal complications occur with some regularity, irrespective of the setting in which the operation is performed. Increasingly, vascular surgeons are encountering older patients with severe comorbid medical conditions that can increase operative morbidity and may significantly elevate mortality. This, in turn, can increase operative morbidity and may significantly elevate mortality for aortic surgery. An alternative form of treatment such as induction of aneurysm thrombosis generally has been abandoned despite preliminary reports ofinitial success.

Transfemoral endoluminal stented graft repair of a popliteal artery aneurysm

This report describes the use of an endoluminally placed stented graft to repair a large (2.6 by 2.6 by 15 cm) popliteal aneurysm in a 63-year-old man with advanced heart disease. Two balloon-expandable stents were attached to a 6 mm polytetrafluoroethylene graft, which was inserted with the patient receiving local anesthetic through a proximal superficial femoral artery arteriotomy. Repeat arteriography and duplex ultrasonography performed up to 3 months after the procedure documented graft and distal artery patency and complete aneurysmal exclusion without distal emboli. This experience demonstrates technical feasibility and early graft patency. However, additional experience and follow-up will be needed to assess the value of this minimally invasive procedure in the management of popliteal aneurysmal disease.

Carotid Artery Stenting Protected With an Emboli Containment System

Background and Purpose— Fear of distal embolization and stroke has aroused concern regarding carotid stenting. Devices to protect the cerebral circulation may make carotid stenting safer. Methods— A multidisciplinary study group tested a balloon occlusion-aspiration emboli entrapment device in conjunction with carotid stenting. The device consists of an elastomeric balloon on a steerable wire with a detachable adapter that inflates and deflates the distal temporary occlusion balloon. An aspiration catheter is used to remove trapped emboli after stenting and before occlusion balloon deflation. Results— Seventy-five patients with severe internal carotid artery stenosis were treated with stents deployed with this cerebrovasculature protection system. All 75 patients (100%) had grossly visible particulate material aspirated, and all were treated successfully without major or minor stroke or death at 30 days. Preintervention stenosis was 81±10%, and residual stenosis was 5±7%. Nine patients (12%) had angiographic evidence of thrombus before intervention, but no patient had thrombus or vessel cutoff after the procedure. Four patients (5%) developed transient neurological symptoms during protection balloon occlusion, but symptoms resolved with balloon deflation. The 22 to 667 particles aspirated per patient ranged from 3.6 to 5262 &mgr;m in maximum diameter (mean, 203±256 &mgr;m). These particles included fibrous plaque debris, lipid or cholesterol vacuoles, and calcific plaque fragments. Conclusions— Protected carotid stenting was performed successfully and safely in this study early in the experience with cerebrovascular protection devices. Particulate emboli are frequent with stenting, and cerebral protection will likely be necessary to minimize stroke. Randomized trials comparing protected carotid stenting with endarterectomy are warranted.

Percutaneous transfemoral insertion of a stented graft to repair a traumatic femoral arteriovenous fistula

This case report describes a new approach to repair a femoral arteriovenous fistula with a transluminally placed intraarterial graft-covered stent. A balloon-expandable stented polytetrafluoroethylene graft was inserted percutaneously to obliterate an arteriovenous fistula after a bullet injured the left superficial femoral artery and vein of an 18-year-old man. Follow-up duplex ultrasonography at 5 months demonstrated patency and luminal integrity of the involved artery and vein, with resolution of the associated pseudoaneurysm. Additional follow-up will be needed to further substantiate the utility of this minimally invasive procedure in the treatment of traumatic arterial injuries.

Relocation of the iliac artery bifurcation to facilitate endoluminal treatment of abdominal aortic aneurysms.

Purpose: To report a surgical technique to preserve the internal iliac arteries (IIAs) and facilitate endovascular repair of abdominal aortic aneurysms (AAAs) with extensive iliac artery involvement. Technique: A new iliac artery bifurcation is created surgically through an 8-cm lower left abdominal incision by implanting the IIA onto the distal external iliac artery either directly or by using a tube graft interposition. Careful technique is required to avoid embolic complications, but after relocating the bifurcation, aortic endografting can be performed, either simultaneously or staged, depending upon patient characteristics. Conclusions: Relocation of the iliac artery bifurcation appears to be a good alternative to preserve pelvic arterial flow in selected candidates for endoluminal AAA repair.

Carotid rupture and intraplaque hemorrhage: Immunophenotype and role of cells involved

BACKGROUND A complete immunohistochemical characterization in complicated carotid plaques is still lacking. The cellular components of 165 carotid endarterectomy specimens were analyzed to assess their role in the pathogenesis of plaque rupture and intraplaque hemorrhage without rupture. METHODS AND RESULTS The fibrous caps at the sites of plaque rupture showed CD68+ macrophages, T-lymphocytes, and scarce B-lymphocytes. Ruptured plaques showed mononuclear infiltrates in the caps, shoulders, and bases of the plaques in 85% of the cases. Only 46% of nonruptured plaques showed such infiltrates (P <.0001). Two types of lipid cores were recognized: avascular or mildly vascularized and highly vascularized. The vessels of the latter type reacted with CD31 and CD34. In 57.5% of the cases, the base and the shoulders of the plaques showed neoformed, CD34+ vessels, often surrounded by mononuclear infiltrates. Intraplaque hemorrhage without rupture had highly vascularized lipid cores in all cases. T-lymphocytes and macrophages were in close contact with neoformed vessels. CONCLUSIONS Plaque rupture is characterized by mononuclear cell infiltration of the caps, whereas intraplaque hemorrhage without rupture is characterized by extensive vascularization of the plaque.

Transfemoral endovascular stented graft treatment of aorto-iliac and femoropopliteal occlusive disease for limb salvage

BACKGROUND Endovascular stented grafts employ a new technique that blends intravascular stent and prosthetic graft technologies. These devices may be used to treat arterial aneurysms, occlusive disease, and vascular injuries. This report describes the application of stented grafts to the treatment of limb-threatening ischemia secondary to occlusive disease of the aorta, iliac, and femoral arteries. METHODS Three patients with limb-threatening ischemia and severe comorbid medical illnesses were treated with transvascular stented grafts that were composed of 6-mm thin-walled polytetrafluoroethylene grafts and Palmaz balloon expandable stents. The grafts were inserted through a cutdown in an artery remote from the site of occlusion and introduced into the vascular system within 14-Fr introducer sheaths. RESULTS Technical success was documented in all three patients with restoration of arterial continuity following stent graft deployment. Patency and limb salvage has been achieved to 1 year. One patient required further dilatation of the proximal stent at 6 weeks. Complications were limited to an iliofemoral deep vein thrombosis in one patient. CONCLUSIONS Endovascular stented grafts can be inserted to treat limb-threatening ischemia. Although these initial results are encouraging, greater experience in more patients observed for longer periods of time is necessary before this technique can be advocated for widespread use.

Endoluminal Aortic Aneurysm Repair Using a Balloon-Expandable Stent-Graft Device: A Progress Report

We describe our experience with endoluminal repair of abdominal aortic aneurysms using the stent-graft device. Twenty-four patients underwent 25 procedures in the 27-month period ending December 31, 1992. Twenty-one of the patients were considered high-risk candidates for conventional surgical repair. The endoluminal stented grafts were aortoaortic in 16 procedures and unilateral aortoiliac in eight. One patient underwent a second procedure consisting of an ilioiliac graft to repair a separate common iliac artery aneurysm. Technical problems were primarily related to retrograde transluminal access across the iliac arteries, tortuous aneurysms, and misjudgments as to measurement of length. One patient died and another required secondary deployment of a distal stent at 4 months; subsequent aneurysm expansion mandated surgical replacement at 18 months. It is clear that this device and methodology will have to undergo further refinement before the technique is acceptable for wider clinical application. Current experience, however, is encouraging. Aneurysm exclusion with an endoluminal prosthesis is likely to become an important therapeutic alternative over the next several years.

Human transluminally placed endovascular stented grafts: preliminary histopathologic analysis of healing grafts in aortoiliac and femoral artery occlusive disease.

PURPOSE The purpose of this study was to perform a preliminary histopathologic analysis of explanted human endovascular stented grafts from patients treated for occlusive disease. METHODS Over a 16-month period, 26 endovascular stented grafts were placed in 21 patients with limb-threatening ischemia caused by aortoiliac or femoral artery occlusive disease. All grafts were inserted through open arteriotomies remote from the region of primary disease. During the follow-up period, two patients died of preexisting heart disease 2 weeks and 7 months after grafting, and a portion of their endovascular grafts were the surrounding artery was explanted. Specimens from five other endovascular grafts were obtained during surgical revision for graft stenosis after 3 and 6 weeks and for outflow artery stenosis after 3, 5, and 6 months. All specimens were formalin fixed and studied with hematoxylin and eosin and trichrome staining and immunohistochemically for factor VIII-related antigen, alpha actin smooth muscle, macrophage antigen (MAC-387) and PC-10 (a mouse monoclonal antibody which specifically recognizes proliferating cell nuclear antigen in paraffin sections). RESULTS Three weeks after placement of the stented grafts, organizing thrombus was present on both surfaces of the expanded polytetrafluoroethylene (PTFE) grafts. At 6 weeks, evidence of a neointima with overlying endothelium was seen in the perianastomotic region, and 3 months after grafting it was seen 1 to 3 cm from the anastomosis. The specimen explanted at 5 months demonstrated factor VIII-positive cells 8 cm from the anastomosis. The histopathologic condition of the external capsule appeared to vary, depending on the presence or absence of an external wrap on the PTFE graft and on which layer in the arterial wall the graft was inserted. A foreign body reaction characterized by multinucleated giant cells was seen adjacent to wrapped grafts or around those placed in an intraadventitial plane. Grafts inserted within the media were surrounded by orderly, arranged, smooth muscle cells and few mononuclear cells. Extensive smooth muscle cell proliferation (PC-10 activity) was not seen within native artery atherosclerotic plaques peripherally displaced and external to prosthetic endovascular grafts. CONCLUSIONS These preliminary observations on the healing of PTFE endovascular stented grafts in human beings demonstrate limited plaque hyperplasia and the presence of endothelial cells on the luminal surface remote from the graft-artery anastomosis. It is unclear whether this is a unique manifestation of healing in prosthetic grafts inserted within the walls of arteries.