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.

Intra-aneurysmal pressure after incomplete endovascular exclusion.

PURPOSE: An endoleak results from the incomplete endovascular exclusion of an aneurysm. We developed an experimental model to analyze hemodynamic changes within the aneurysm sac in the presence of an endoleak, with and without a simulated open collateral branch. METHODS: With a latex aneurysm model connected to a pulsatile pump, pressures were measured simultaneously within the system (systemic pressure) and the aneurysm sac (intrasac pressure). The experiments were performed without endoleak (control group) and after creating a 3.5-mm (group 1), 4.5-mm (group 2), and 6-mm (group 3) diameter orifice in the endograft, simulating an endoleak. Pressures were also registered with and without a patent aneurysm side branch. RESULTS: In each endoleak group, the intrasac diastolic pressure (DP) and mean pressure (MP) were significantly higher than the systemic DP and MP (P =.01, P =.006, and P =.001, respectively), although the pressure curve was damped. The presence of an open side branch significantly reduced the intrasac DP and MP. CONCLUSION: In this model, intrasac pressures were significantly higher than systemic pressures in the presence of all endoleaks, even the smallest ones. Intrasac pressures higher than systemic pressure may pose a high risk for aneurysm rupture. Although patent side branches significantly reduce these pressures, the aggressive management of an endoleak should be pursued.

Neutrophil respiratory burst activity and pro- and anti-inflammatory cytokines in AAA surgery: conventional versus endoluminal treatment.

PURPOSE: To examine the inflammatory impact of endovascular and conventional surgery of abdominal aortic aneurysm (AAA) as assessed by the activation of neutrophils and serum levels of pro- and anti-inflammatory cytokines. METHODS: Twenty-four patients undergoing AAA exclusion were treated with either endovascular (n = 14) or conventional (n=10) techniques. Clinical and hematological data, respiratory burst of neutrophils, and the expression of adhesion and activation molecules (CD18, CD11b, CD69, and HLA-DR) were analyzed by flow cytometry. The enzyme-linked immunosorbent assay technique was used to measure proinflammatory cytokine interleukin (IL)-8 and anti-inflammatory cytokines IL-1 receptor antagonist (IL-1RA) and transforming growth factor beta1 (TGF-beta1). RESULTS: All patients, most of whom had normal cytokine values before surgery, were successfully treated. No significant changes were found in surface antigens. Basal respiratory burst was quite heterogeneous; in all cases respiratory burst activity decreased after surgery and remained low throughout the observation period. Despite marked interpatient differences, IL-1RA and IL-8 increased after surgery, whereas TGF-beta1 decreased, although the variation achieved statistical significance only in the conventional group. Elevated IL-1RA returned to normal within 48 hours in the endoluminal group, whereas the level remained high in the conventional group in the last sample. CONCLUSIONS: Despite heterogeneity before surgery, the respiratory burst decreased for most of the patients regardless of the approach, and both techniques increased IL-1RA. Although both procedures seemed to decrease TGF-beta1, the difference was significant only with the conventional approach. IL-1RA levels fell toward basal values quicker in the endograft patients, suggesting that the endoluminal approach was less aggressive.

Initial evaluation of carotid angioplasty and stenting with three different cerebral protection devices.

OBJECTIVE: The purpose of the study was to assess the effectiveness of cerebral protection devices during carotid artery angioplasty and stent placement. METHODS: Between September 1998 and September 1999, carotid angioplasty and stenting were performed in 46 patients with symptomatic (39.1%) or asymptomatic (60.9%) severe carotid artery stenosis. Wallstents were used in all patients with selective predilatation. Cerebral protection devices were used in 25 of these patients. Primary end points were perioperative neurologic complications and mortality. Data were collected prospectively. RESULTS: The overall combined end point of all neurologic deficits and death rate was 4.34%. Two neurologic events (one transient ischemic attack and one minor stroke) occurred in the unprotected group (9.53%) versus none in the group with cerebral protection. This difference is not statistically significant. The mortality rate was 0% for both groups. On an intention to treat basis, the overall technical success rate for carotid angioplasty was 97.8%, and for placement of cerebral protection devices it was 100%. An important number of particles of different sizes were captured in all cases in which cerebral protection devices were used. CONCLUSION: Experience has shown that cerebral protection during carotid angioplasty and stenting is technically feasible and appears to be effective in preventing procedure-related neurologic complications. Further investigation is warranted.

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.

Acute rupture of an aortic false aneurysm treated with a stent-graft.

PURPOSE: To report the use of an aortic endograft to treat a ruptured false aneurysm at the anastomosis of an aortofemoral bypass graft. METHODS AND RESULTS: A 68-year-old man with a 30-year-old aorto-right femoral bypass and multiple comorbidities was admitted to the hospital complaining of acute abdominal pain. Imaging identified a 60-mm ruptured aortic false aneurysm with associated retroperitoneal hematoma, a 9-cm right femoral false aneurysm, and a calcified 23-mm left common iliac aneurysm. Two slightly overlapping Vanguard straight stent-grafts were implanted in the aorta and left common iliac artery in an emergency procedure owing to the patient's high surgical risk. The anastomotic false aneurysm and the bypass were excluded. A left-to-right femorofemoral bypass was performed to re-establish flow to the right femoral artery with ligation of the external iliac artery. The patient recovered uneventfully. He remained well with a successful repair until his death of a myocardial infarction 6 months after the procedure. CONCLUSIONS: Endovascular grafting can be used successfully for the urgent treatment of aortic false aneurysm rupture.

Endovascular stent-graft treatment of traumatic arterial lesions.

Twenty-nine cases of post-traumatic false aneurysms and arteriovenous fistulas (AVF), with a mean follow-up of 24 months (1-65 months), are presented here. Diagnosis was established by color duplex and arteriogram. The time between injury and treatment varied between 3 days and 61 months. Endovascular treatment was accomplished using a covered Palmaz stent [vein, polytetrafluoroethylene (PTFE), or polyester], Corvita endoluminal graft, or a Wallgraft. Complimentary treatment of a branch injury was performed using a detachable balloon in one patient. The initial result was favorable for all patients. One case of asymptomatic stenosis of an iliac stent graft and three occlusions of the stent (one subclavian, one axillary, and one internal carotid) were registered during the follow-up period, and no clinical manifestations of the occlusions were reported. Endovascular treatment of post-traumatic false aneurysms and AVF appears to be a promising alternative for treatment of these lesions. Less pain and disability as well as rapid recovery time and lower cost after endovascular treatment compare favorably to the standard surgical technique.

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.

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 treatment of abdominal aortic aneurysms: lessons learned.

The authors offer an overview of their 20-year involvement in the development of an endovascular graft for abdominal aortic aneurysm exclusion. Clinical experience gained throughout 6 years of clinical evaluation are reviewed, along with observations and insights on preoperative assessment, implantation techniques, and complications.

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.