The association of clinical variables and filter design with carotid artery stenting thirty-day outcome.

OBJECTIVE: Patient and device selection are important for the success of carotid artery stenting (CAS). We hypothesize that distal protection filter (DPF) design characteristics that minimize blood flow resistance and maximize capture efficiency are associated with the absence of transient ischemic attack (TIA), stroke and neurologic-related death after 30 days. METHODS: Records from 208 patients were reviewed retrospectively. Filter design characteristics were quantified previously in our laboratory. The association between risk factors and design characteristics with 30-day outcome was quantified using univariate analysis. RESULTS: The 30-day all-cause stroke and death rate was 8.7% (asymptomatic: 7.7%, symptomatic: 10.6%). Five DPFs were used in the study: Accunet (41.3%), Angioguard (33.2%), FilterWire (24%), Emboshield (1%), and Spider (.5%). Diabetes (P = .04) and prior carotid endarterectomy (CEA, P = .03) were associated with adverse outcome. Prior stroke (P = .01) and prior CEA (P = .04) were significant for peri-procedural stroke. Design characteristics such as capture efficiency were associated with favorable outcomes. CONCLUSIONS: Patients with prior CEA or stroke are more likely to have unfavorable CAS outcomes after 30 days. Filters with high capture efficiency may yield the best clinical results. Analysis of the effect of design characteristics on CAS outcome should aid the design of future devices.

Current status in cervical carotid artery stent placement.

Based upon recent and old medical literature, with the exception of high surgical risk symptomatic patients, there remains much debate on how to manage extracranial carotid arterial disease, whether by surgical or endovascular intervention or by medical therapy alone. A review of the various global current carotid artery stent and endarterectomy registries and trials was performed incorporating more than 14,000 patients who have received carotid stents. There is substantial evidence supporting the benefit of carotid artery stenting (CAS) for the high anatomic risk population. Complication rates with symptomatic patients, including octogenarians, continue to show trend towards improvement as operators gain experience. The results are limited for standard risk carotid stenting for symptomatic patients though results with recent trials are pending but will probably show equivalence with endarterectomy. The asymptomatic patient population remains controversial: there is a small but reproducible benefit for revascularization. Long term (1-3 years) neurological results are now being reported for the major registries and trials. Analysis of target lesion revascularization, stroke and death rates of carotid stenting is comparable or better than rates for endarterectomy. Carotid artery stent placement has met the CMS targets 3% for MAE for asymptomatic patients and 6% for symptomatic patients with numerous registries and trials. CAS has also proven outcomes at 3 years with restenosis rates and stroke-free rates comparable or better than CEA. CAS provides an option for patients not suited for medical therapy and who were high-risk for CEA, especially for those symptomatic patients. It is still controversial with the role of stenting asymptomatic patients as well as for octogenarians. However, forthcoming trials will be helpful in providing more insight. Despite questionable studies and bad press, carotid stenting in the right hands with good patient selection is an excellent procedure. Finally, it is important to remember, carotid stenting is still in its early development and will only get better.

The expanding indications for virtual histology intravascular ultrasound for plaque analysis prior to carotid stenting.

Complications of carotid artery stenting (CAS), including stroke, remain relatively high when compared with carotid endarterectomy (CEA). Current selection criteria for patients undergoing CAS are based predominately on surgical risk related to other comorbidities. Little attention is given to the morphology of the atherosclerotic plaque, although studies have shown that extensive variability exists which confers certain risks for plaque vulnerability. Virtual Histology intravascular ultrasound (VH IVUS) offers a unique method of assessing plaque morphology prior to CAS. Herein, the authors review the concepts of atherosclerotic plaque morphology and discuss the background of VH IVUS and illustrate its use in the carotid system. With selection of the appropriate patient and the appropriate plaque, more favorable outcomes of CAS may be achieved which will solidify its place as a frontline treatment of carotid vascular disease.

Current status in cervical carotid artery stent placement.

Aim of this paper is to provide background information and the latest developments and studies pertaining to carotid artery stent placement in the treatment of carotid artery occlusive disease. A review of current literature combined with personal experience in the field of carotid stenting is presented. Endovascular stent placement for carotid artery occlusive disease is evolving from its initial controversial position to that of an alternative treatment of extracranial carotid artery disease. The high technical success (98-99%) as well as the relatively few complications makes carotid stenting a substitute for carotid endarterectomy for symptomatic patients and especially those with high medical comorbidities. With the advent of distal embolic protection, the complication rates for carotid stenting have decreased by approximately 50% to 2-4% for most major centers. Hence, with improved technology, carotid stenting is becoming an option for asymptomatic patients, especially those with high surgical risk. Early results for patency and neurological follow-up have also been encouraging. When we first began performing carotid stenting in 1995, we used a mixture of peripheral and coronary techniques. As stent design, guide catheters and cerebral protection devices have become dedicated and sophisticated, the technical success, patency and complication rates have improved. Carotid stenting will increase in application in the future especially among high surgical-risk patients with symptomatic and asymptomatic carotid occlusive disease.

Performance of a hybrid central venous catheter utilized for both peripheral blood stem cell harvest and transplant support of patients undergoing autologous peripheral blood stem cell transplantation.

Patients undergoing autologous peripheral blood stem cell transplantation (PBSC) frequently require the sequential insertion of two central venous catheters, one for leukapheresis and one for transplant support. Hybrid catheters suitable for leukapheresis and long-term use have been increasingly used, but there is limited information regarding their performance and complication rate. The purpose of this study was to determine the performance of the Pheres-Flow hybrid catheter when utilized for both leukapheresis and transplant support, with particular emphasis on the incidence of infectious and occlusive complications. We prospectively analyzed the performance of 92 catheters in 82 consecutive patients who underwent autologous peripheral blood stem cell (PBSC) transplantation. Occlusion was the most frequent complication of this catheter with 29% of the patients experiencing difficulty drawing blood or infusing fluids. Infection was another frequent complication. Twenty-two percent of patients developed catheter-related bloodstream infections and 15 catheters had to be removed because of proven or suspected infection that did not respond to antibiotic therapy. Nevertheless, 77% of patients were able to complete leukapheresis and transplant support with only one catheter. We conclude that the utilization of the Pheres-Flow catheter for both leukapheresis and transplant support is feasible, but that new strategies need to be developed to decrease the incidence of occlusive and infectious complications of hybrid catheters.

Management of neurological complications of carotid artery stenting.

PURPOSE: To review the neurological complications associated with extracranial carotid artery stenting and to preliminarily assess techniques used to manage these complications. METHODS: Between April 1994 and August 2000, 450 patients (270 men; mean age 70.2 years, range 27-89) had stents implanted to treat 472 cervical carotid artery stenoses. Over half (257, 57%) of the patients were symptomatic. A variety of stents were implanted percutaneously after predilation of the lesion; a third of the patients received glycoprotein IIb/ IIIa inhibitors intraprocedurally in addition to a standard oral antiplatelet regimen (aspirin and ticlopidine or clopidogrel). Occurrence and management of neurological complications within the 30-day periprocedural period were reviewed. RESULTS: There were 14 (3.1%) transient ischemic attacks (TIAs), 10 (2.2%) minor strokes, and 3 (0.7%) major strokes. Among 6 (1.3%) procedure-related deaths, 4 had neurological causes. The total stroke and death rate was 4.2% (n = 19). All the TIAs, 4 of which occurred between 1 and 14 days poststenting, were treated medically, as were the minor strokes, 3 of which occurred >24 hours after stenting. Only 2 minor stroke patients had mild residual upper extremity motor deficits. Intra-arterial thrombolytic therapy was administered in 5 cases (2 major strokes survivors and 3 patients who suffered a neurologically-related death); occlusions were identified in the proximal middle cerebral artery (MCA) in 3 and the distal MCA in 2. Angiographic improvement was noted in 4 (80%), but only the 2 (40%) with distal MCA occlusions did well clinically. CONCLUSIONS: Neurological complications following carotid artery stenting are inevitable. The occurrence of minor strokes >24 hours following stenting may indicate a possible late embolic phenomenon, which warrants investigation. Likewise, the marginal efficacy of intra-arterial thrombolytic therapy demonstrates an inability to lyse embolic plaque and underscores the need for effective distal protection.

Current status of carotid bifurcation angioplasty and stenting based on a consensus of opinion leaders.

OBJECTIVE: Carotid bifurcation angioplasty and stenting (CBAS) has generated controversy and widely divergent opinions about its current therapeutic role. To resolve differences and establish a unified view of CBAS' present role, a consensus conference of 17 experts, world opinion leaders from five countries, was held on November 21, 1999. METHODS: These 17 participants had previously answered 18 key questions on current CBAS issues. At the conference these 18 questions and participants' answers were discussed and in some cases modified to determine points of agreement (consensus), near consensus, (prevailing opinion), or divided opinion (disagreement). RESULTS: Conference discussion added two modified questions, placing a total of 20 key questions before the participants, representing four specialties (interventional radiology, seven; vascular surgery, six; interventional cardiology, three; neurosurgery, one). It is interesting that consensus was reached on the answers to 11 (55%) of 20 of the questions, and near consensus was reached on answers to 6 (30%) of 20 of the questions. Only with the answers to three (15%) of the questions was there persisting controversy. Moreover, both these differences and areas of agreement crossed specialty lines. Consensus Conclusions: CBAS should not currently undergo widespread practice, which should await results of randomized trials. CBAS is currently appropriate treatment for patients at high risk in experienced centers. CBAS is not generally appropriate for patients at low risk. Neurorescue skills should be available if CBAS is performed. When cerebral protection devices are available, they should be used for CBAS. Adequate stents and technology for performing CBAS currently exist. There were divergent opinions regarding the proportions of patients presently acceptable for CBAS treatment (<5% to 100%, mean 44%) and best treated by CBAS (<3% to 100%, mean 34%). These and other consensus conclusions will help physicians in all specialties deal with CBAS in a rational way rather than by being guided by unsubstantiated claims.

Covered stent for renal artery aneurysm.

This is a case of a 51-year-old female with difficult-to-control hypertension and a 3-cm renal artery aneurysm. Successful exclusion of this was performed using a prefabricated stent graft. To our knowledge, this is the first report on the use of a prefabricated covered stent for this indication.

Modified technique for using vascular sheaths in carotid artery stent placement.

PURPOSE: To report a technical modification that will prevent sheath kinking in acutely angled vessels during carotid stent placement. TECHNIQUE: If a long vascular sheath kinks when engaging an acutely angled common carotid or innominate artery, the sheath is pulled caudally approximately 2 cm while a 0.014-inch guidewire, supported by a coronary balloon catheter, is advanced toward the internal carotid artery (ICA). Alternatively, to avoid kinking, the original 0.035-inch super stiff wire is maintained within the sheath until the 0.014-inch wire and coronary balloon have exited the sheath's distal tip. CONCLUSIONS: If an aortic arch is tortuous and the angle of the common carotid artery is unfavorable, a guiding catheter is preferable to a long vascular sheath for accessing the ICA during carotid stent procedures.

Endovascular AAA repair in a patient with a horseshoe kidney and an isthmus mass.

PURPOSE: To report the endovascular exclusion of an abdominal aortic aneurysm (AAA) in a patient with a horseshoe kidney and an isthmus mass with preservation of accessory renal vessels. CASE REPORT: A 70-year-old man with a 5-cm AAA and renal cell carcinoma involving a horseshoe kidney was treated with an AneuRx bifurcated graft. Two accessory renal arteries believed to feed the isthmus mass were sacrificed, but 2 other accessory renal arteries from the left common iliac artery (CIA) were preserved by using an extension cuff to cover the aneurysmal left CIA distal to their origins. The right renal isthmus mass decreased in size on follow-up imaging. At 9 months, there was no endoleak evident on computed tomographic scans, and the aneurysm measured 4.8 cm. CONCLUSIONS: The presence of accessory renal arteries in AAA patients with horseshoe kidneys should not automatically exclude them from consideration for endovascular repair. Creative stent-graft arrangements can be a treatment option.

Cerebral protection systems for distal emboli during carotid artery interventions.

Carotid angioplasty and stenting is associated with liberation of cerebral emboli that can cause periprocedural stroke. There are currently three classes of emboli protection devices (EPDs) that are undergoing feasibility studies and one randomized clinical trial. Preliminary data from a small series appear to be promising, and there appears to be attenuation of embolic signals on a cerebral Doppler exam with EPD use. However, rare strokes and patient intolerance due to imposed ischemia have been observed. The advantages and disadvantages of each EPD class and the issues involving clinical trials and surrogate end points in this area of study are discussed.

New developments in endovascular interventions for extracranial carotid stenosis.

We provide an overview of recent developments in carotid interventional technique and equipment, including new stents and emboli protection devices. The newer self-expanding stents lessen the problem of external stent compression associated with balloon expandable stents, but precise deployment and the matching (by length) of stents to lesions remain problematic. We also discuss emerging pharmacologic strategies for cerebral protection in stroke. Multiple randomized clinical trials and multicenter registries are under way to compare percutaneous with surgical strategies for the treatment of carotid stenosis. These include the evaluation of emboli protection devices, and, to a lesser degree, intravenous glycoprotein IIb/IIIa antagonists. Other clinical trials are aimed towards refining the ability to stratify patients by risk, in order to identify the subsets that would benefit most from these complex and expensive procedures.

Safety, efficacy, and durability of carotid artery stenting for restenosis following carotid endarterectomy: a multicenter study.

PURPOSE: To present the results of a multicenter registry established to collect data on carotid stent procedures in patients with restenosis following carotid endarterectomy. METHODS: The procedural details, outcomes, and late follow-up results were collected from 14 centers in the United States. Thirty-day and late stroke and death rates were analyzed. RESULTS: Three hundred and thirty-eight patients (201 men; 71 +/- 8 years) underwent carotid stenting in 358 arteries. The average duration from carotid endarterectomy was 5.5 +/- 7.3 years. Sixty-one percent of the patients were asymptomatic. The overall 30-day stroke and death rate was 3.7%. The minor stroke rate was 1.7% (6/358), and the major nonfatal stroke rate was 0.8% (3/358). The fatal stroke rate was 0.3% (1/358), and the nonstroke-related death rate was 0.9% (3/338). There was 1 (0.3%) fatal and 1 (0.3%) nonfatal stroke during the follow-up period. The overall 3-year rate of freedom from all fatal and nonfatal strokes was 96% +/- 1% (+/- SE). CONCLUSIONS: Carotid artery stenting can be performed in patients with restenosis following carotid endarterectomy with 30-day complication rates comparable to those of most published studies on repeat carotid endarterectomy. Results of late follow-up suggest that this technique is durable and efficacious.

Global experience in cervical carotid artery stent placement.

The purpose of this article is to review and update the current status of carotid artery stent placement in the world. Surveys to major interventional centers in Europe, North and South America, and Asia were initially completed in June 1997. Subsequent information from these 24 centers in addition to 12 new centers has been obtained to update the information. The survey asked the various questions regarding the patients enrolled, procedure techniques, and results of carotid stenting, including complications and restenosis. The total number of endovascular carotid stent procedures that have been performed worldwide to date included 5,210 procedures involving 4,757 patients. There was a technical success of 98.4% with 5,129 carotid arteries treated. Complications that occurred during the carotid stent placement or within a 30-day period following placement were recorded. Overall, there were 134 transient ischemic attacks (TIAs) for a rate of 2.82%. Based on the total patient population, there were 129 minor strokes with a rate of occurrence of 2.72%. The total number of major strokes was 71 for a rate of 1.49%. There were 41 deaths within a 30-day postprocedure period resulting in a mortality rate of 0.86%. The combined minor and major strokes and procedure-related death rate was 5.07%. Restenosis rates of carotid stenting have been 1.99% and 3.46% at 6 and 12 months, respectively. The rate of neurologic events after stent placement has been 1.42% at 6-12-month follow-up. Endovascular stent treatment of carotid artery atherosclerotic disease is growing as an alternative for vascular surgery, especially for patients that are high risk for standard carotid endarterectomy. The periprocedure risks for major and minor strokes and death are generally acceptable at this early stage of development and have not changed significantly since the first survey results. Cathet. Cardiovasc. Intervent. 50:160-167, 2000.