Microembolization during carotid stenting with the distal-balloon antiemboli system.

BACKGROUND: The distal-balloon protection system is being evaluated for its efficacy in preventing embolic neurological events during carotid stenting (CAS). We sought to determine the effect of this system on the frequency of the Doppler-detected microembolic signals (MES) during CAS. METHODS: Using transcranial Doppler, we compared the frequency of MES during CAS in 2 groups; 39 patients without distal protection and 37 with the distal-balloon protection system (GuardWire, Percusurge, Sunnyville, CA). There was no significant difference in the clinical or angiographic characteristics between the 2 groups. Three phases with increased MES counts were identified during the unprotected CAS; stent deployment, predilation, and postdilation (mean+/-SD: 75+/-57, 32+/-36, and 27+/-25, respectively). RESULTS: The distal-balloon protection significantly reduced the frequency of MES during CAS (MES-counts: 164+/-108 in the control vs 68+/-83 in the protection group, p=0.002) particularly during these 3 phases. MES in the protection group were detected predominantly during sheath placement, guidewire manipulation and during the distal-balloon deflation. CONCLUSIONS: Three phases with increased MES counts were identified during the unprotected CAS, e.g. stent deployment, predilation and postdilation. The distal-balloon protection system significantly reduced the frequency of MES during CAS, particularly during these 3 phases.

Subarachnoidal hemorrhage following carotid stenting with the distal-balloon protection.

A 61-year-old man underwent carotid stenting with the distal-balloon protection system for symptomatic carotid artery stenosis. During the procedure, progressive elevation of the systolic blood pressure occurred, reaching a peak of 220 mm Hg immediately following deflation of the distal balloon. This was associated with severe headaches and progressive deterioration in the mental status to a coma. Head CT scan showed massive subarachnoidal hemorrhage contralateral to the stented side and a secondary intracerebral hemorrhage. Despite immediate successful blood pressure control, his condition deteriorated and he died 2 days later.

Effect of the distal-balloon protection system on microembolization during carotid stenting.

BACKGROUND: The distal-balloon protection system is being evaluated for its efficacy in preventing embolic neurological events during carotid stenting (CAS). We sought to determine the effect of this system on the frequency of Doppler-detected microembolic signals (MES) during CAS. METHODS AND RESULTS: Using transcranial Doppler, we compared the frequency of MES during CAS in 2 groups: 39 patients without distal protection and 37 who used the distal-balloon protection system (GuardWire). There were no significant differences in the clinical or angiographic characteristics between the 2 groups. Three phases with increased MES counts were identified during unprotected CAS; these were stent deployment, predilation, and postdilation (75+/-57, 32+/-36, and 27+/-25 METS, respectively). The distal-balloon protection significantly reduced the frequency of MES during CAS (MES counts: 164+/-108 in the control versus 68+/-83 in the protection group; P=0.002), particularly during these 3 phases. MES in the protection group were detected predominantly during sheath placement, guidewire manipulation, and distal-balloon deflation. CONCLUSION: Three phases with increased MES counts were identified during unprotected CAS (eg, stent deployment, predilation, and postdilation). The distal-balloon protection system significantly reduced the frequency of MES during CAS, particularly during these 3 phases.

Procedural safety and short-term outcome of ambulatory carotid stenting.

BACKGROUND AND PURPOSE: Ambulatory procedures increase patient comfort and enhance cost-effectiveness. We sought to determine the feasibility and safety of ambulatory carotid stenting. METHODS: A selected group of patients was admitted and discharged the same day after the carotid stenting procedure. Immediate and short-term outcomes are reported. RESULTS: A total of 98 ambulatory carotid stenting procedures (98 hemispheres in 92 patients) were performed. There were 66 men (72%), and the mean age was 70+/-9 years. Of the patients, 28% had neurological symptoms related to the treated artery within 3 months before the procedure. Sixteen percent of the patients had prior carotid endarterectomy, 4% had prior ipsilateral neck radiation, and 8% had complete occlusion of the contralateral internal carotid artery. Successful access site hemostasis was ensured in all patients with suture-mediated vascular closure devices in 96 (98%) and manual compression in 2. Clinical follow-up was available for 96% of the patients at a mean time of 6+/-4 months. There were no neurological events, deaths, repeated procedures, or major access site complications. CONCLUSIONS: Ambulatory carotid stenting is both safe and feasible. This approach will enhance the applicability of the procedure by increasing patient comfort and potentially reducing procedural costs.

Embolization via collateral circulation during carotid stenting with the distal balloon protection system.

PURPOSE: To describe a potential route for embolization to the middle cerebral artery (MCA) during carotid stenting with the distal balloon protection system. CASE REPORT: An 82-year-old man with symptomatic severe carotid artery stenosis underwent elective carotid stenting with distal-balloon protection. Despite complete occlusion of the distal internal carotid artery, frequent emboli were detected in the ipsilateral MCA by transcranial Doppler (TCD) during the procedure. Intracranial angiography, performed during the distal-balloon protection, revealed filling of the MCA through collaterals from the ipsilateral external carotid artery. The procedure was successfully completed without complications. The patient remains asymptomatic at 6 months. CONCLUSIONS: During carotid stenting with distal-balloon protection, asymptomatic embolization into the ipsilateral MCA may occur through collateral circulation. The clinical significance of these emboli is uncertain.

Emergency stenting to treat neurological complications occurring after carotid endarterectomy.

OBJECTIVES: The purpose of this study was to assess the efficacy of emergency stent implantation for the treatment of perioperative stroke after carotid endarterectomy (CEA). BACKGROUND: Carotid endarterectomy has been proven safe and effective in reducing the risk of stroke in symptomatic and asymptomatic patients with >60% carotid artery stenosis. However, perioperative stroke has been reported in 1.5% to 9% of CEA cases. The management of such a complication is challenging. Recently, percutaneous transluminal carotid angioplasty with stent deployment has emerged as a valuable and alternative strategy for the treatment of carotid artery disease. METHODS: Between April 1998 and February 2000, 18 of the 995 patients (1.8%) who had CEA in our institution experienced perioperative major or minor neurological complications. Of these, 13 patients underwent emergency carotid angiogram and eventual stent implantation, whereas the remaining five had surgery re-exploration. RESULTS: Carotid angiogram was performed within 20+/-10 min and revealed vessel flow-limiting dissection (five cases) or thrombosis (eight cases). Percutaneous transluminal carotid angioplasty with direct stenting (self-expandable stent) was performed in all 13 cases. Angiographic success was 100%. Complete remission of neurological symptoms occurred in 11 of the 13 patients treated by stent implantation and in one of the five patients treated by surgical re-exploration (p = 0.024). CONCLUSIONS: Stent implantation seems to be a safe and effective strategy in the treatment of perioperative stroke complicating CEA, especially when carotid dissection represents the main anatomic problem.

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.

Immediate and late clinical outcomes of carotid artery stenting in patients with symptomatic and asymptomatic carotid artery stenosis: a 5-year prospective analysis.

BACKGROUND: Carotid stenting is a less invasive percutaneous procedure than carotid endarterectomy for the treatment of carotid stenosis. Reports suggest that it can be performed with periprocedural complication rates similar to those of carotid endarterectomy. The purpose of this study was to determine short- and long-term outcomes in the largest prospective cohort of carotid stenting patients. METHODS AND RESULTS: This study followed 528 consecutive patients (604 hemispheres/arteries) undergoing carotid stenting. There was a 0.6% (n=3) fatal stroke rate and 1% (n=5) nonstroke death rate at 30 days. The major stroke rate was 1% (n=6), and the minor stroke rate was 4.8% (n=29). The overall 30-day stroke and death rate was 7.4% (n=43). Over the 5-year study period, the 30-day minor stroke rate improved from 7.1% (n=7) for the first year to 3.1% (n=5) for the fifth year (P:<0.05 for trend). The best predictor of 30-day stroke and death was age >/=80 years. After the 30-day period, the incidence of fatal and nonfatal stroke was 3.2% (n=31). On Kaplan-Meier analysis, the 3-year freedom from ipsilateral or fatal stroke was 92+/-1%. CONCLUSIONS: Experience from a single group of operators demonstrates that carotid stenting can be performed with an acceptable 30-day complication rate. Late follow-up also demonstrates a low rate of fatal and nonfatal stroke. These results suggest that carotid stenting may be comparable to carotid endarterectomy, and it underscores the clinical equipoise and premise for the National Institute of Health-supported, randomized Carotid Revascularization Endarterectomy Versus Stent Trial comparing carotid stenting with carotid endarterectomy.

Carotid angioplasty with stenting in post-carotid endarterectomy restenosis.

Recurrent stenosis post-carotid endarterectomy (CEA) is not a solitary or unusual phenomenon. Compared to the initial CEA, the reoperation is often more technically challenging and frequently results in local and neurological complications. Carotid artery angioplasty with stenting (CAS) is currently being investigated as an alternative to carotid endarterectomy. In our study, ninety-nine patients underwent CAS in 110 arteries. Procedural success was 99% (109/110). Our results show that CAS treatment in post-CEA restenosis, especially with improved technique and distal protection, is safe with a low neurological complication rate, without any "local" complications and without any cranial nerve palsies. This study suggests that the future primary mode of treatment of post-CEA restenosis might be carotid stenting rather than surgery.

Integrated minimally invasive approaches for the treatment of atherosclerotic vascular diseases: Hybrid procedures.

Patients may develop simultaneous symptoms of atherosclerotic vascular disease from different arterial beds. A concurrent minimally invasive approach to the management of these clinical situations may be an advantage over conventional surgical procedures. This study describes two separate case series of patients undergoing coronary/peripheral (n = 38) and peripheral/peripheral procedures (n = 10). Technical and clinical success was achieved in all patients. There were two periprocedural complications (retroperitoneal bleed and septicemia) in the coronary/peripheral series and no complications in the peripheral/peripheral series. We also present five case reports to illustrate the utility of hybrid procedures in various clinical settings. This study suggests that the use of simultaneous or sequential minimally invasive procedures appears to be a safe and feasible strategy for the treatment of patients with symptoms from more than one vascular bed. Cathet Cardiovasc Intervent 2001;52:154-161.

Validity of duplex ultrasound as a diagnostic modality for internal carotid artery disease.

There is an increasing trend to rely on duplex ultrasound rather than angiography to measure an internal carotid artery stenosis. The aim of this study was to determine the validity of ultrasound assessment of carotid stenosis performed in community based vascular laboratories. We compared ultrasound with angiography in 225 patients referred to us for carotid intervention. Mild lesions were diagnosed by ultrasound with a sensitivity of 54%, specificity of 89%, and a positive predictive value of 89% compared with angiography. Severe lesions had a sensitivity of 93%, a specificity of 67%, and a positive predictive value of 45%. Receiver operator characteristic curves demonstrated the optimal ultrasound cut-off value of 66% stenosis as a predictor of >60% stenosis measured angiographically, is associated with a false positive rate of 38%, and a false negative rate of 9%. Similarly, if a cut-off of 76% on ultrasound is used to predict >70% stenosis measured angiographically, it would be associated with a 29% false positive rate and a false negative rate of 11%. Despite the value of non-invasive testing for carotid disease, duplex ultrasonography performed in non-accredited and some accredited laboratories may produce highly variable results. Using ultrasound as the sole diagnostic test to determine the severity of a carotid stenosis may result in a high number of inappropriate operations and a large proportion of patients who may not be offered treatment due to false negative diagnoses.

Carotid stenting with distal-balloon protection via the transbrachial approach.

PURPOSE: To document the feasibility of brachial artery access for carotid stenting with distal-balloon protection of the internal carotid artery (ICA). TECHNIQUE: Via percutaneous access to the brachial artery, a large double-curve catheter is advanced into the aortic arch over a hydrophilic guidewire to cannulate the left common carotid artery. Following sheath exchange, a GuardWire distal-protection balloon is positioned within the left ICA distal to the stenosis. The lesion is dilated, followed by deployment and dilation of a self-expanding stent. Transcranial Doppler monitoring shows only scarce microembolic signals during the procedure. CONCLUSIONS: Carotid stenting with distal balloon protection via the brachial artery appears feasible as an alternative to standard femoral access.

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.

Photoactivation of vascular iNOS and elevation of cGMP in vivo: possible mechanism for photovasorelaxation and inhibition of restenosis in an atherosclerotic rabbit models.

Recently, intravascular low-power red laser light (LPRLL) therapy has been proposed for the prevention of postangioplasty restenosis due to the observed inhibition of experimental neointimal formation. The objective of this study was to determine the impact of endoluminal LPRLL on vascular levels of inducible nitric oxide synthase (iNOS) and cyclic guanosine monophosphate (cGMP) to help define the mechanism of this effect. Eight atherosclerotic male adult New Zealand White rabbits weighing 4-6 kg were used in these studies. The iliac arteries were treated in separate zones with: (1) balloon inflation only; (2) laser illumination only; and (3) balloon inflation + laser illumination. An uninjured zone of the iliac artery served as a control. Laser irradiation (630 nm) was delivered to the vessel wall via a Cold laser Illuminator (Cook, Inc., Bloomington, IN), with a 3 mm-diameter balloon. Experiments demonstrated that vascular cGMP levels obtained immediately following treatment in the balloon only group was the lowest (0.29 +/- 0.05 pmol/mg protein) and significantly lower compared with the uninjured controls (1.01 +/- 0.07 pmol/ mg protein) (P < 0.001). In the laser only treated group cGMP levels were significantly increased (2.87 +/- 0.12 pmol/mg protein) compared with the uninjured control (P < 0.001) and the balloon only group (P < 0.001). Vascular cGMP levels in the balloon + laser group (2.09 +/0.07 pmol/mg protein) was also increased compared to the balloon only (P < 0.001) and control (P < 0.001) groups. Qualitative analysis of Western blot demonstrated that laser illumination induces iNOS. In contrast balloon dilatation did not induce iNOS. Balloon + laser treatment, however, tended to restore the expression of iNOS. Our study demonstrated that intravascular low dose laser irradiation induces iNOS and elevates vascular cGMP in an in vivo atherosclerotic rabbit model.

Carotid artery stenting: technical considerations.

BACKGROUND AND PURPOSE: Carotid endarterectomy (CEA) is one of the most frequently performed operations in the United States. To offer patients a less invasive means to achieve the same goal, carotid artery stenting (CAS) is investigated as an alternative treatment to CEA. METHODS: Three hundred ninety patients underwent CAS, with 451 vessels treated. CAS was performed using a coaxial system with a 7F 90-cm sheath for predilation, stent placement, and stent dilation. Pretreatment antiplatelet therapy was administered. We currently practice same-day admissions and 23-hour discharges. RESULTS: The technical success rate was 98%. The 30-day mortality/morbidity rates were as follows: death, 1.7% (two [0.5%] neurologic and five [1.2%] systemic] major strokes, 0.9% (two of four were related to the intervention); minor strokes, 5.5%. Among 25 patients who suffered minor strokes, 14 achieved complete recovery. On an annual basis, the incidence of minor stroke declined from 6.8% (1994-1995), to 5.8% (1995-1996), 5.3% (1996-1997), and then 4% (1997-1998), with no major strokes or neurologic deaths occurring during the 1997 to 1998 period. CONCLUSION: CAS is an effective treatment for carotid stenosis. With proper selection of patients and meticulous technique, complication rates compare favorably with those of CEA.

Randomized comparison of GR-II stent and Palmaz-Schatz stent for elective treatment of coronary stenoses.

BACKGROUND: This prospective multicenter randomized clinical trial was designed to evaluate the long-term angiographic and clinical outcomes of elective treatment with the GR-II stent compared with the Palmaz-Schatz (PS) stent in patients with coronary stenoses. METHODS AND RESULTS: Seven hundred fifty-five patients with myocardial ischemia and de novo native coronary stenoses in 3- to 4-mm vessels were randomly assigned to the PS (375 patients) or the GR-II stent (380 patients). The primary end point was 12-month target lesion revascularization (TLR)-free survival. Angiography was performed at baseline and at follow-up in the first 300 consecutive patients to assess the frequency of angiographic restenosis. Procedure success was 98.5% for the GR-II stent and 99.4% for the PS stent (P:=0.19). At 30 days, patients assigned to the GR-II stent had a higher stent thrombosis rate (3.9% versus 0.3% for PS stent, P:<0.001) and TLR rate (3.9% versus 0.5% for PS stent, P:<0.001). The GR-II group had a higher follow-up restenosis frequency (47.3% versus 20.6% for the PS group, P:<0.001) and a lower 12-month TLR-free survival rate (71.7% versus 83.9% for the PS group, P:<0. 001). Multivariate logistic regression analysis identified a smaller final stent minimal lumen diameter (odds ratio [OR] 2.49, 95% CI 1. 56 to 3.98; P:<0.001), diabetes mellitus (OR 2.14, 95% CI 1.42 to 3. 22; P:<0.001), and use of the GR-II stent (OR 1.78, 95% CI 1.20 to 2. 64; P:<0.01) as independent determinants of 12-month TLR. CONCLUSIONS: On the basis of these long-term follow-up data, we conclude that use of the GR-II stent should be limited to the acute treatment of abrupt or threatened closure after failed conventional balloon angioplasty procedures.

Techniques of carotid artery stenting: the state of the art.

The technique of carotid stenting has undergone significant refinement since its introduction and continues to improve as experience with the procedure matures and more suitable equipment becomes available. Improved stent designs and the utilization of cerebral protection devices are expected to significantly impact on the technique, its ultimate outcomes, and widespread application. In using the currently available technology for carotid stenting, patient selection and meticulous attention to procedural details are very important in minimizing embolic events. In this article, we provide a comprehensive practical discussion of the state-of-the-art carotid stenting techniques that have allowed us to maintain low event rates.