Stent-graft treatment of trauma to the supra-aortic arteries. A review.

Trauma to the carotid, subclavian, vertebral, or innominate arteries may be blunt or penetrating. Some injuries, such as those caused by central venous catheterization, are iatrogenic. Trauma-induced fistulas and pseudoaneurysms of the supra-aortic arteries are relatively rare, but may result in disabling neurologic symptoms or death. Traditional surgical approaches to supra-aortic artery trauma have high morbidity and mortality rates, especially in patients with multiple injuries and patients with a serious concomitant illness. The minimally invasive endovascular approach may offer an alternative that avoids the tissue damage, bleeding, infectious complications, pain and disability, long recovery time, and high financial cost associated with surgery. In the past 15 years, stent-grafts have evolved from bare-metal stents to which the operator attached autologous vein or a prosthetic material to manufactured balloon-expandable or self-expanding endoprosthetic systems. No devices designed specifically for use in the supra-aortic arteries are yet available. Nevertheless, the reported experience with stent-graft treatment of supra-aortic artery trauma is growing rapidly, although it remains limited to case reports and small series with relatively short follow-up times. Results have been very promising: complete lesion exclusion from the circulation and resolution of symptoms has been achieved in almost all cases, and few procedural complications and stent-graft stenoses and thromboses have been reported. The stent-graft approach warrants additional research on its long-term outcomes, as well as continued development of enhancements for the devices used.

Initial 200 cases of carotid artery stenting using a reversal-of-flow cerebral protection device.

AIM: Because embolic complications can occur during carotid angioplasty and stenting (CAS), a new device, the Parodi Anti-Emboli System (PAES) was developed to protect the brain from embolization. We describe our initial experience with this device. METHODS: Between September 1999 and December 2003, CAS was performed in 200 consecutive patients (146 men; mean age, 70.4 years) with symptomatic (52%) or asymptomatic (48%) severe carotid artery stenosis (>70%). De novo lesions were present in 169 patients, restenosis in 18, and radiation-induced stenosis in 13. Wallstents were inserted in all cases, with selective predilatation, and the PAES was employed during all CAS procedures. Patients were evaluated by a neurologist before and after CAS. Minor strokes, major or fatal strokes, and myocardial infarctions that occurred within 30 days of the procedure were recorded. RESULTS: The overall technical success rate for CAS using the PAES (with the PAES placed in position percutaneously) was 99%. The overall perioperative stroke and death rate was 1.5%. There were four transient neurologic events after CAS, three of which were related to hemodynamic instability and one to postoperative embolization. CONCLUSIONS: Our experience indicates that CAS using the PAES is safe and effective. The protection device may prevent the debris released by angioplasty from entering the cerebral circulation. Additional studies of this device are warranted.

Is there evidence that cerebral protection is beneficial? Clinical data.

Advances in angioplasty techniques and the development of low-profile, flexible, tapered nitinol stents designed specifically for carotid applications have made carotid artery stenting a viable alternative to carotid endarterectomy for treatment of occlusive disease of the carotid arteries. During the stenting process, however, debris may be released and cause distal embolization that can lead to stroke or death. Thus, several embolic protection devices have been developed for use in carotid stenting, two of which are available in the United States. In the past 5 years, data from several large trials, series, and registries of carotid artery stenting-reflecting the experience in thousands of patients-have become available. These investigations include the CAVATAS study, the Global Carotid Artery Stent Registry, the SAPPHIRE study, the ARCHeR trials, the CABERNET registry, the BEACH registry, the SECuRITY registry, the German Registry, and the EVA-3S trial. The studies have provided considerable evidence that use of an embolic protection device decreases the incidence of cerebral embolic events during carotid stenting in both symptomatic and asymptomatic patients. They have also shown that increased experience with angioplasty in the carotid artery decreases complication rates associated with the procedure, even when a protection device is not employed. Although the benefits of routine use of cerebral protection have not been confirmed by level 1 evidence, a consensus supports such use.

Techniques for carotid artery stenting under cerebral protection.

Carotid angioplasty and stenting is an alternative to carotid endarterectomy in the treatment of carotid artery stenosis. During the stenting process, however, distal embolization usually occurs, and the particles released may cause neurologic problems or death. Thus, the safety of carotid stenting depends partly on use of a cerebral protection device during the procedure. Three principal types of protection mechanisms have been developed: distal balloon occlusion, distal filtration, and proximal occlusion with or without reversal of flow. Products using these mechanisms have been manufactured by a variety of companies, and many are used routinely outside the United States (US). One distal filter, the RX Accunet, has been approved by the US Food and Drug Administration for clinical use. Large clinical trials of most of the newest carotid stents and cerebral protection devices are under way, and some initial results have been reported. Several clinical series in which cerebral protection was employed have also been described. Each type of protection device has advantages and disadvantages, which are discussed in this review.

Transfemoral, endovascular stented graft repair of an abdominal aortic aneurysm.

Endovascular aortic graft implantation is a new procedure for the repair of arterial aneurysms. We report on the first such case successfully performed in the United States. A 76-year-old man with severe oxygen-dependent pulmonary insufficiency, coronary artery disease, and recurrent ventricular tachyrhythmia was also diagnosed as having a 7.5-cm infrarenal abdominal aortic aneurysm. Because of the high risks associated with conventional surgical repair, consent was obtained for compassionate use of an experimental device. Using local anesthesia, a 22-mm Dacron prosthesis was inserted under fluoroscopic guidance through an open, left transfemoral route. Completion arteriography demonstrated aneurysm exclusion. No blood transfusion was required and there were no perioperative complications. Further technical refinements and clinical trials will be required prior to the broad implementation of this technique.

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.

Varying strategies and devices for endovascular repair of abdominal aortic aneurysms.

The endovascular repair of abdominal aortic aneurysms has been investigated in a clinical setting since 1991. Although initially the procedure was performed using surgeon-made devices, it did not take long for the medical industry to realize the potential of this procedure. There are six commercially made devices, which are unique, each with their own strengths and weaknesses. This article describes the principal endovascular graft types that are currently under investigation as well as the strategies for their use. In addition, the inclusion criteria for endovascular repair of abdominal aortic aneurysms are discussed.

Endovascular repair of aortic aneurysms, arteriovenous fistulas, and false aneurysms.

The diagnosis of abdominal aortic aneurysms (AAA) has been established with increasing frequency during the past two decades. This is probably due to the aging of the population as well as to the extensive use of ultrasonography and computerized tomography (CT) scanning for different pathologies. Although AAA may occasionally cause distal embolization, rupture remains the most common and deadly complication. Elective replacement with a synthetic graft has proved to be the most appropriate method to prevent AAA rupture for nearly 40 years, and at respected medical centers, it has been associated with a postoperative mortality of less than 5%. Non-fatal complications occur with some regularity irrespective of the setting in which the operation is performed. Increasingly, vascular surgeons are encountering older patients with severe co-morbid conditions. This can increase operative morbidity and may even elevate mortality of aortic surgery to a figure in excess of 60%. It seems inevitable that every vascular surgeon will, with some frequency, encounter patients who represent a prohibitive risk for conventional graft replacement, yet alternative forms of treatment (such as axillofemoral bypass in conjunction with induced AAA thrombosis) generally have been abandoned despite preliminary reports of their initial success.

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.

Endovascular aortic devices: the Parodi and Palmaz system.

Based on the concept of endoluminal aneurysm exclusion, we began to develop a plan for endovascular treatment for abdominal aortic aneurysm (AAA) in 1976.Two prototypes have been developed and were marked by a high failure rate.' The first was a thin fabric graft mounted on a metallic cage-like structure composed by a self-expandable mesh with a zigzag configuration. The apparatus was compressed inside a tubular sheath, which acted as a vessel introducer and carrier. Experiments in normal canine aor- tas led to the abandonment of this prototype due to an inconsistent deployment of the metallic cage. The radial expansion properties of the cage were difficult to control and predict. Over-expansion resulted in aortic wall injury and subsequent rupture. Controversially, underexpansion led to leakage of blood be- tween the apparatus and the host aorta with subsequent device migrations. The second prototype involved a Dacron graft fitted on a Silastic bag with a cylindrical lumen, which could be distended by injection of silicone into the bag. Unfortunately, this method was associated with prompt graft thrombosis of the aorta in all experimental essays.

Stented drafts for the treatment of arterial vascular disease.

Vascular surgery has evolved considerably over the past 100 years from a specialty that offered patients only palliative procedures to treat significant vascular diseases to a field centered on the diagnosis and correction of vascular disorders. Aortic and peripheral artery aneurysms were once medical problems rarely diagnosed and frequently fatal. Diffuse, occlusive arterial disease secondary to atherosclerosis frequently resulted in limb gangrene or specific end-organ ischemia. Modern vascular therapy has dramatically reduced the incidence of primary limb amputations and significantly decreased the risk of fatal complication of arterial aneurysm rupture.

Endovascular repair of abdominal aortic aneurysms and other arterial lesions.

PURPOSE: This report describes our experience with endovascular stented graft repair of abdominal aortic aneurysms and other arterial lesions. METHODS: Between September 1990 and April 1994, 57 patients were treated with endovascular stented grafts (50 with abdominal aortic aneurysms or iliac aneurysms; five with traumatic arteriovenous fistulas; one with an infected femoral false aneurysm; and one with a false aneurysm of the proximal right common carotid artery). The devices consist of either a Dacron or an autogenous vein graft sutured to a balloon-expandable stent. The stented grafts are placed through remote arteriotomies, advanced under fluoroscopic guidance to their predetermined sites, and secured into position. RESULTS: Forty of the 50 endovascular stented graft procedures used to treat abdominal aortic aneurysms or iliac aneurysms were considered successful, even though some secondary treatment was required in six patients (two open operations; four secondary endovascular procedures). The 10 failures include four early procedural deaths, one late procedural death, and five leaks. All five arteriovenous fistulas and the two false aneurysms were successfully treated with endovascular stented grafts. CONCLUSIONS: Although our experience with endovascular stented grafts has been promising, remaining problems require resolution, and further follow-up is needed. However, the potential advantages of these endovascular grafts warrant their continued evaluation.

Endovascular stent graft repair of aortic aneurysms.

Vascular surgeons are increasingly encountering older patients with large aneurysms associated with severe comorbid conditions. This situation can increase operative morbidity and elevate the mortality rate of aortic surgery over 60%. With some frequency many patients will represent a prohibitive risk for conventional graft replacement. The endoluminal treatment of 110 patients has proved to be feasible and may represent an alternative solution. One hundred six of the patients had an abdominal aortic aneurysm and in four patients, the thoracic aorta was involved. All of them underwent endoluminal repair for the aortic pathology using the combination of stents and grafts in aorto-aortic or aorto-iliac position, with straight, tapered, or bifurcated stent-graft devices. The results are as follows: Initial success was 84% in aorto-aortic abdominal devices and 100% in aorto-aortic thoracic devices. In aorto-iliac devices, initial success was 75%. Late success rates were 62% of the initial group and 80% of the initially successful group.

Endovascular repair of aortic aneurysms, arteriovenous fistulas, and false aneurysms.

Between September 1990 and June 1995, 103 patients were treated with transluminal placed endovascular grafts: 87 had abdominal aortic aneurysms (AAA), two had iliac artery aneurysms (one in association with an AAA), 3 had thoracic aneurysms, and 12 had vascular injuries in various localization of the arterial tree. The AAAs were excluded from the blood flow with a device composed of a balloon-expandable stent (modification of the Palmaz stent) attached to a Dacron graft designed to expand at both ends of the accompanying stent extension. An 18F sheath containing the stent-graft device was introduced through a small cut-down in the common femoral arteries and advanced under fluoroscopic guidance. Color duplex, contrast-enhanced computed tomography (CT) scanning and angiography were performed before the procedure and then every 6 months. (Arteriography was performed once during the follow-up period and whenever other studies disclosed an abnormal finding.) A total of 87 patients (75 men, 12 women) harboring an AAA were treated: Forty-five patients underwent an aortoaortic procedure (8 patients had only a proximal stent implanted, and 37 had proximal and distal stents). Forty-two patients were treated by implanting an aortoiliac graft, completing the procedure with a femorofemoral bypass. The contralateral common iliac artery was occluded by means of an occluding stent. One type A dissecting aneurysm and two descending thoracic aneurysms were successfully treated by the endovascular technique. The longest follow-up period was 60 months and the shortest 1 month. Initial success was obtained in 84% of the aortoaortic cases and in 75% of the aortoiliac procedures. Long-term follow-up (> 12 months) disclosed 78% success for the aortoaortic cases and 90% for the aortoiliac procedures. Late failures included distal aortic dilatation, distal leak into the aneurysmal cavity, and proximal leak into the aneurysm. All trauma cases were successful over the short and long terms. Trauma cases included false aneurysms (common carotid, subclavian, common femoral arteries) and arteriovenous fistulas (subclavian, aortocava, common iliac-cava and superficial femoral artery and vein). We concluded that stent-graft combination devices appear to be an alternative for treating vascular trauma and aneurysms. Initial success for treating AAAs is almost 100%, and late success in aortoiliac cases is also high (90%) for aortoaortic reconstruction. However, late failures are frequent and require further evaluation in relation to a persistent increase in the diameter of the proximal neck and distal cuff.

Gadolinium-based contrast: an alternative contrast agent for endovascular interventions.

The radiocontrast substance gadoterate meglumine (Gd-DOTA) is used in magnetic resonance imaging. Because of its low rate of adverse drug reactions, we evaluated Gd-DOTA as an alternative contrast medium in diagnostic and therapeutic procedures. Twenty-three consecutive procedures were performed using undiluted contrast agent Gd-DOTA (376.9 mg/mL, Dotarem) in digital subtraction techniques. A dosage of 30-90 mL was used. Serum creatinine levels were registered before and at 24 and 48 hr after the procedure. Based on this limited experience, Gd-DOTA may be used as an alternative contrast agent in selected endovascular procedures, when iodine is contraindicated.

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.

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.