Extracranial Carotid Artery Stenting Research Articles

Extracranial carotid artery stenting followed by intracranial stent-based thrombectomy for acute tandem occlusive disease

ObjectiveAcute tandem occlusions of the extracranial internal carotid artery (ICA) and a major intracranial artery respond poorly to intravenous tissue plasminogen activator (tPA) and present an endovascular challenge. We describe...

Safety of Preprocedural Antiplatelet Medication in Coil Embolization of Ruptured Cerebral Aneurysms at the Acute Stage

Preoperative antiplatelet medication for aneurysm coil embolization during acute subarachnoid hemorrhage (SAH) is not common. However, recent advances in neurointerventional devices make antiplatelet medication necessary for SAH surgery. We tested the hypothesis that preprocedural antiplatelet therapy in the acute stage of SAH prevents complications due to ischemia or induced bleeding. We retrospectively reviewed 35 consecutive ruptured cerebral saccular aneurysms that underwent coiling at our institute. Two hundred milligrams of aspirin and 150 mg of clopidogrel were administered to the patients at least two hours before coiling. Systemic heparinization was given after sheath insertion. Procedure-related thrombus formation on digital subtraction angiography, and clinical evidence of ischemia and procedure-related stroke on CT were reviewed. The median patient age was 69 years. Five males and 30 females were included. Seventy-seven percent of patients were Hunt-Hess grades 1 to 3. Assist techniques were used in 20 cases (57%). We inserted one extracranial internal carotid artery stent, but no intracranial stent. Intraoperative thrombosis occurred in one case (2.9%), with no clinical symptoms. Postoperative cerebrospinal fluid drainage was done in three cases, but we experienced no bleeding complications. Preoperative antiplatelet therapy leads to a low rate of thromboembolic events in coiling during acute stage SAH, and this strategy had no adverse influence on bleeding complications.

Clinical Investigation of Fasudil for the Prevention of Cerebral Vasospasm in Extracranial Carotid Artery Stenting

To evaluate fasudil hydrochloride for the prevention of cerebral vasospasm (CVS) in extra-cranial carotid angioplasty and stenting (CAS). We retrospectively analyzed 178 patients with unilateral CAS who were given intravenous fasudil hydrochloride during the perioperative period. CVS, hypotension, stroke, and mortality incidence rates were recorded. Of the cohort studied, 80.9 % patients exhibited no local CVS, asymptomatic vasospasm was observed in 17.4 % patients and symptomatic vasospasm in 1.7 % patients via DSA imaging. All CVS was relieved and symptoms disappeared after intra-arterial infusion of papaverine hydrochloride. Intracerebral hemorrhage occurred in two cases during the perioperative period, one of which resulted in death. CVS is a severe complication of CAS. Fasudil hydrochloride can rapidly relieve cerebral vasospasm, has no selective effect on cerebral vasculature, and little influence on blood pressure. It is suitable for the prevention of CVS during interventional treatment of ischemic cerebrovascular disease.

Single-Stage Extracranial Carotid Artery Stenting and Intracranial Aneurysm Coiling: Technical Feasibility and Clinical Outcome

The coexistence of carotid artery stenosis and cerebral aneurysm in a patient presents challenges for treatment decision-making. The purpose of this study was to evaluate the technical feasibility and clinical outcome after single-stage extracranial carotid artery stenting (CAS) and ipsilateral intracranial aneurysm coiling in a single institution. From March 2005 to February 2011, 17 patients with 21 aneurysms underwent single-stage CAS and coiling for ipsilateral aneurysms. There were symptomatic atherosclerotic carotid stenoses with unruptured aneurysms in eight, ruptured or symptomatic aneurysms with simultaneous asymptomatic carotid stenoses in two and asymptomatic lesions in seven. CAS was followed by aneurysm coiling in all 17 patients. Clinical and radiological data were reviewed. There were two procedure-related complications: acute in-stent thrombosis in one and premature aneurysmal rupture in the other. After aneurysm coiling, complete occlusion was demonstrated in 17 aneurysms and near-total occlusion in four. No neurological deficit was found at discharge and follow-up outcomes were excellent in all the patients (mean, 32.9 months). Follow-up imaging studies were performed in all the patients, including neck CT angiography in 14 (mean, 26.1 months), brain MR angiography in 14 (mean, 31.2 months), and conventional angiography in three (mean, 14.7 months). They revealed two asymptomatic, mild carotid re-stenoses and one major aneurysmal recanalization requiring re-coiling. A single-stage CAS and coiling procedure appears to be feasible and the complication rate seems to be reasonable. We suggest that there is no need for separate therapeutic procedures when a patient has carotid artery stenosis and accompanying ipsilateral intracranial aneurysm.

Routinely transradial arterial approach for extra-cranial carotid stenting

Background The purpose of this study is to report a single center experience with its safety and feasibility of transradial arterial (TRA) approach in extra-cranial carotid artery (ECCA) stenting. Methods and results 74 patients were consecutively enrolled in this study. A retrograde-engagement technique, involving looping 6-F Kimny guiding catheter, was utilized for ECCA angiographic study. For ECCA stenting, the 6-F Kimny guiding catheter was replaced with a 7-F Kimny guiding catheter and the procedure was performed as the follows. First, a 0.035-in. Teflon wire was carefully advanced into the common CA. Second, a PercuSurge GuardWire was inserted into the external CA, followed by distal balloon inflation for an anchoring support. Third, the 6-F guiding catheter was removed, followed by exchanging a 7-F kimny guiding catheter which was advanced along the 0.035-in. Teflon wire and the PercuSurge GuardWire to proximal part of common CA. Distal protection device was then utilized to protect from distal embolization during the procedure. One procedure failed due to external CA did not provide an anchoring support. Thus, the procedure was successful in 74 (98.7%) patients. No vascular or bleeding complication was observed. Minor stroke occurred in 3 (4.0%) patients during the procedure. All of them were completely recovery within 1 week. Conclusions The TRA approach for ECCA stenting is safe and feasible. This access may offer a last resort for patients with unsuited to femoral arterial access and endarterectomy.

Abstract 162: Rescue Carotid Stenting To Reestablish Flow In The Middle Cerebral Artery And Anterior Cerebral Artery In Patients Who Present With Acute Ischemic Stroke And Carotid Occlusion

Introduction: Acute ischemic stroke due to the occlusion of the internal carotid artery (ICA) is associated with malignant stroke and poor outcome. Without revascularization of ICA, perfusion to the middle cerebral artery (MCA) and anterior cerebral artery (ACA) is not possible. Objective: Objective of our study is to evaluate the technical feasibility of emergent extracranial carotid artery revascularization using stent and to evaluate the impact of stenting in distal cerebral perfusion. Method: From an established stroke database consecutive patients with acute ischemic stroke who underwent emergent extracranial carotid artery stenting and thrombolysis/clot retrieval of the MCA and ACA from July 2007 to December 2008 were enrolled. Patients’ demographics including presenting National Institute of Health Stroke Scale (NIHSS), degree of revascularization, hemorrhagic conversion and 30 days outcome data using Glasgow Outcome Scale (GOS) were collected. Result: Successful ICA stenting was possible in 20/21 (95%) patients. The mean age of patients was 62 plus-minus 15 years and mean NIHSS was 18 plus-minus 5. Carotid stenting facilitated successful revascularization of the MCA and ACA using TPA (tissue plasminogen activator) and MERCI (mechanical embolus removal in cerebral ischemia) clot retriever device in 18 patients (85.7%), 14 (67%) of which has achieved complete recanalization in the MCA and ACA. In complete recanalization group, a 4 point or higher NIHSS improvement was observed in 11/14 (78.5%) patients. Symptomatic intracranial hemorrhage was observed in 9.5% patients. Seven (50%) of 14 patients who achieved complete recanalization had a good outcome. Five (71%) of 7 patients who did not achieve complete recanalazation of the MCA and ACA died and had NIHSS 20 or higher. NIHSS 20 or higher was associated with incomplete recanalization of the MCA and ACA and poor outcome. Conclusion: Emergent extracranial carotid artery revascularization using stent is not only technically feasible in patients with acute ischemic stroke who present with acute carotid artery occlusion, but it also facilitates successful reestablishment of flow in the MCA and ACA with good outcome. Further study is necessary.

Abstract 2383: The Antiplatelet Effect Of Clopidogrel Is Associated With CYP2C19 *2 And *3 Polymorphism But Not With Pon-1 Q192R Polymorphism In Japanese Patients Undergoing neurointervention

Background Patients with cervical carotid or intracranial stenting are routinely premedicated with antithrombotic agents, clopidogrel and aspirin (ASA). A recent study has showed paraoxonase-1 (PON-1) Q192R genotypes impacts on antiplatlet effect of clopidogrel rather than CYP2C19 mutation. We investigate the influence of CYP2C19 *2, *3, and PON-1 Q192R genotypes on antiplatelet effect of clopidogrel in Japanese patients scheduled for neurointervention such as extracranial carotid artery stenting, intracranial artery stenting, or coil embolization of the cerebral aneurysm. Method A total of 102 consecutive patients scheduled for neurointervention and treated with ASA and clopidogrel were enrolled. Genotyping of three single-nucleotide polymorphisms (SNPs) defining the two major CYP2C19 alleles *2, *3 and PON-1 Q192R was performed with the use of TaqMan® SNP Genotyping Assays (Applied Biosystems, CA) from stored DNA. Antiplatlet effect of clopidogrel was assessed by VerifyNow P2Y12 assay. Result The frequencies of CYP2C19 *1/*1, *1/*2, *1/*3, *2/*2, *2/*3, and *3/*3 were 28 (27.5%), 39 (38.2%), 13 (12.7%), 9 (8.8%), 11 (10.8%), and 2 (2.0%), respectively. On the basis of CYP2C19 genotype, 28 patients (27.5%) were classified as an extensive metabolizer (EM), 52 (51.0%) as an intermediate metabolizer (IM) and 22 (21.6%) as a poor metabolizer (PM). The proportion of patients harboring CYP2C19 loss of function SNPs is 72.5%. The frequencies of PON-1 QQ192, QR192, and RR192 were 8 (7.8%), 52 (51.0%), and 42 (41.2%), respectively. P2Y12 reaction unit (PRU) in the VerifyNow P2Y12 assay was significantly higher in patients with CYP2C19 loss of function SNPs than those without (253.6±100.2 vs. 161.3±85.5, P<0.001). However, the PRU in patients with QR192 or RR192 were not significantly different from those with QQ192 ( 227.0±128.1 vs. 228.8±103.0, P=0.973). Conclusion: In Japanese patients undergoing neurointervention, antiplatlet effect of clopidogrel was associated with CYP2C19 genotype *2and *3 but not with PON-1 Q192R genotype.

Bivalirudin Used as Alternative Anticoagulant in Carotid Artery Stenting: A Single Center Observational Study

To analyze and report the safety and effectiveness of bivalirudin in a large patient population undergoing carotid artery stenting (CAS). Between January 2001 and November 2010 extracranial CAS was performed in 272 patients in our institution. These patients were stratified according to the anticoagulant used during the CAS procedure into 2 groups (bivalirudin n = 217 vs. unfractionated heparin [UFH] n = 55) and analyzed regarding bleeding complications and periprocedural (within 30 days) stroke and myocardial infarction (MI) rates. The combined end-point of death, stroke, and MI occurred in 12 patients (4.4%) with no significant difference between the groups (bivalirudin 4.6% vs. UFH 3.6% P value 0.96). Stroke rates were 1.8% in the bivalirudin and 1.8% in the UFH group (P value 1.00), with 4/5 strokes being nondisabling. Periprocedural MI was observed in 7 patients (2.1%) with no significant differences between the groups (bivalirudin 2.7% vs. UFH 1.8%, P value 0.94). Bleeding complications occurred in 13/272 patients (4.7%) with no significant difference between the groups (bivalirudin 3.6% vs. UFH 9.0%, P value 0.15). The first activated clotting time after administration of the anticoagulants was therapeutic in 209/217 (96%) in the bivalirudin group and in 30/55 (55%) in the UFH group (P < 0.001). In this single-center study, bivalirudin was a safe and efficient anticoagulation strategy for CAS and could be considered a therapeutic alternative to UFH.

Endovascular carotid artery stenting and early coronary artery bypass grafting for asymptomatic carotid artery stenosis: Long‐term outcomes and neurologic events

Optimal management of patients with asymptomatic critical carotid artery stenoses prior to coronary artery bypass grafting (CABG) has no clear consensus. Further, optimal timing for surgical coronary revascularization has not been defined after or with any carotid revascularization. We reviewed the data from 2002 to 2007, of all patients in our institution who underwent carotid artery stenting (CAS) for critical carotid artery stenoses, prior to CABG. Twenty patients with critical carotid disease were referred for preoperative carotid intervention prior to CABG. Carotid duplex demonstrated evidence of critical stenoses in all patients. Patients were serially assessed by a stroke neurologist before and after the procedure (immediately, at 24 hr, at 48 hr, immediately following CABG, and at 30 days). We evaluated initial procedural success as well as freedom from periprocedure stroke. Prior to undergoing CABG, 20 patients had stents placed in a single carotid artery for unilateral asymptomatic critical carotid artery stenoses. All the procedures, except one, were performed with distal embolic protection. Patients received aspirin and clopidogrel. There were no strokes or deaths up to a mean follow up of 486 days. The mean time from CAS to CABG performed in the same hospital admission was 6.4 days. Transfusion rates were not excessive despite dual antiplatelet therapy. In a real-world setting, endovascular extracranial CAS for asymptomatic carotid artery stenosis by experienced operators, prior to CABG was safe and permitted early coronary revascularization without increased risk of strokes or death in this high-risk cardiovascular patient population.

Initial Experience in Establishing an Academic Neuroendovascular Service: Program Building, Procedural Types, and Outcomes

To report our initial experience in setting up a neuroendovascular service in a university-based comprehensive stroke center. We determined the rates of referral path, procedural type, and independently adjudicated 1-month outcomes (actual rates) in first 150 procedures (120 patients) and subsequently compared with rates derived from pertinent clinical trials after adjustment for procedural type (predicted rates). The patients were referred from the emergency department (n= 44), transferred from another hospital (n= 13), or admitted for elective procedures from the clinic (n= 63). The procedures included treatment of acute ischemic stroke (n= 12); extracranial carotid stent placement (n= 33); extracranial vertebral artery stent placement (n= 13); intracranial angioplasty and/or stent placement (n= 12); embolization for intracranial aneurysms (n= 35), arteriovenous malformations (n= 5), and tumors (n= 10); cerebral vasospasm treatment (n= 26); and others (n= 4). The technical success rate was 100% for intracranial aneurysm obliteration and extracranial carotid artery stent placement, and 95% for those undergoing intracranial or vertebral artery stent placements; and partial or complete recanalization was achieved in 72% of patients undergoing intra-arterial thrombolysis. After adjusting for procedural type, the actual adverse event rate of 3% compared favorably with the predicted rate of 7% based on the results of clinical trials. We provide estimates of procedure volumes and outcomes observed in the initial phase of setting up a neuroendovascular service with an active training program.

Protection Filter–Related Events in Extracranial Carotid Artery Stenting:A Single-Center Experience

To report the complications, rescue procedures, and consequences related to the use of an embolus protection filter during carotid artery stenting (CAS). A retrospective review was undertaken of 72 patients (58 men; mean age 70.0+/-8.2 years, range 56-87) with extracranial atherosclerotic carotid stenosis who underwent 77 CAS procedures under filter protection. Filter-related events and rescue procedures according to each procedural step were retrospectively evaluated on CAS angiograms. In addition, neurological events and outcomes were also assessed. CAS using a filter was successful in 99% of cases, and the overall rate of minor stroke (n=1), major stroke (0), or mortality (n=1) was 2.6% at 30 days. Filter placement was successful in all cases. However, arterial tortuosity made it difficult for a filter to pass through the stenosis in 1 case; this was overcome with an additional supportive wire (0.018-inch). Filter-related events were flow impairment in 6 (7.8%), filter wedging in the catheter tip in 4 (5.2%), vasospasm >50% narrowing in 7 (9.1%), filling defects within the filter membrane in 5 (6.5%), retrieval failure with the provided retriever in 3 (3.9%), and insecure retrieval without filter collapse in 2 (2.6%). Flow impairment caused drowsy mentality and impaired verbal response in 4, which resolved after prompt filter retrieval. All the cases of filter wedging were resolved with a catheter pulled down into the stented segment to separate the filter element from the catheter tip. Significant vasospasm and filling defects were spontaneously resolved in all cases after filter retrieval. Inability to pass a retriever catheter through a stent was overcome with curved 5-F catheter manipulation in all 3 cases. The use of a filter during CAS may induce various angiographic or technical events at each step. For a severely stenotic and tortuous carotid lesion with difficult access, a filter may become trapped or irretrievable during flow arrest. Physicians should be aware of the preventive and rescue maneuvers to counter filter-related events, perhaps even considering another type of protection mechanism or carotid endarterectomy.

Fatal Intraventricular Hemorrhage After the Extracranial Carotid Artery Angioplasty and Stent Placement

We report on a 72-year-old female with an unusual intracranial bleeding complication after an extracranial carotid artery stenting procedure performed for a tight left ICA stenosis associated with contralateral carotid occlusion. Two hours after the procedure, the initial signs of intracranial bleeding appeared that led to the patient's demise 5 days later. A brain CT showed and autopsy proved massive intraventricular bleeding. To our knowledge, our case is only the second report of isolated reperfusion intraventricular hemorrhage post-CAS.

Endovascular repair of an infected carotid artery pseudoaneurysm

Pseudoaneurysm formation after carotid endarterectomy is a rare but potentially lethal complication. The risks for embolization and continued expansion necessitate repair. Traditional surgical repair of carotid pseudoaneurysms is often technically demanding, and is associated with relatively high morbidity and mortality. Endovascular stent grafts have been used to treat both posttraumatic and postoperative carotid pseudoaneurysms. An endovascular approach to these pseudoaneurysms limits the risks for operative damage to surrounding structures and the potential for substantial blood loss. We present the case of an infected carotid pseudoaneurysm that was successfully treated with a covered stent graft.

Intracranial Haemorrhage Probably Due to an Angiographically Occult AVM after Carotid Stenting

Angiographically occult vascular malformations refer to cerebrovascular malformations that are not demonstrable on technically satisfactory cerebral angiography. Authors herein present a very unusual intracranial bleeding complication related to an angiographically occult vascular malformation after extracranial carotid artery stenting procedure. A 52-year-old male patient admitted to the hospital with 2 episodes of amaurosis fugax in the left eye. Cervical carotid angiography and bilateral carotid Doppler ultrasonography revealed a 98% stenosis of the left internal carotid artery just distal to the bifurcation. Post-stenting control cervical carotid angiography revealed neither any residual stenosis nor a developmental venous anomaly. The patient developed left pupil dilatation with loss of consciousness two hours after the neurovascular intervention. Emergent cranial CT showed acute subdural haematoma, intracerebral and subarachnoid haemorrhage with massive midline shift. He underwent an emergent craniotomy with left temporal lobectomy. Abnormal cortical vascular structures with prominent engorgement were remarkable over the posterior temporal cortex. Histopathological studies confirmed the diagnosis of an occult AVM. Classically, these lesions are not visualized with angiography.Our patient's cerebral angiography and MR investigations were all normal. To our knowledge this is the first case in literature in which intracranial haemorrhage (acute subdural haematoma, intracerebral haematoma, SAH) occurred due to hyperperfusion of angiographically occult vascular malformation.

Extracranial carotid artery stenting in surgically high-risk patients using the Carotid Wallstent endoprosthesis: midterm clinical and ultrasound follow-up results.

The purpose of this study was to evaluate the feasibility, safety and midterm outcome of elective implantation of the Carotid Wallstent in patients considered to be at high surgical risk. In a prospective study, 54 carotid artery stenoses in 51 patients were stented over a 24-month period. Three patients underwent bilateral carotid artery stenting. Institutional inclusion criteria for invasive treatment of carotid occlusive disease (carotid endarterectomy or carotid artery stenting) are patients presenting with a 70% or more symptomatic stenosis and those with an 80% or more asymptomatic stenosis having a life-expectancy of more than 1 year. All patients treated by carotid artery stenting were considered at high risk for carotid endarterectomy because of a hostile neck (17 patients--31.5%) or because of severe comorbidities (37 patients--68.5%). No cerebral protection device was used. Of the 54 lesions, 33 (61.1%) were symptomatic and 21 (38.8%) were asymptomatic. Follow-up was performed by physical examination and by duplex ultrasonography at 1 month, 6 months, 1 year and 2 years after the procedure. All 54 lesions could be stented successfully without periprocedural stroke. Advert events during follow-up (mean 13.9 +/- 5.7 months) were non-stroke-related death in 6 patients (11.1%), minor stroke in 4 stented hemispheres (7.4%), transient ipsilateral facial pain in 1 patient (1.8%), infection of the stented surgical patch in 1 patient (1.8%) and asymptomatic instent restenosis in 4 patients (7.4%). The percutaneous implantation of the Carotid Wallstent, even without cerebral protection device, appears to be a safe procedure with acceptable clinical and ultrasonographic follow-up results in patients at high surgical risk. But some late adverse events such as ipsilateral recurrence of non-disabling (minor) stroke or instent restenosis still remain real challenging problems.

Evaluation of glycoprotein IIb/IIIa inhibitors in carotid angioplasty and stenting.

To review the immediate neurological and bleeding complications associated with the use of glycoprotein (GP) IIb/IIIa inhibitors in patients undergoing extracranial carotid artery stent placement. A retrospective review was performed of 550 patients (321 men; mean age 71.1 years, range 28-91) who underwent carotid artery angioplasty and stent placement. Glycoprotein IIb/IIIa inhibitors were given prophylactically along with heparin to 216 patients, whose outcomes were compared to a control group of 334 patients who received intravenous heparin alone. Primary endpoints were the immediate and 30-day neurological complications, including transient ischemic attacks (TIAs), minor and major strokes, and neurologically-related deaths. The secondary endpoint was any abnormal bleeding. The all stroke/neurological death rate in 216 patients treated with heparin and GP IIb/IIIa inhibitors was 6.0% (13 events) compared 2.4% (8 events) in the 334 patients in the heparin-only control group (p=0.0430). Two of the 4 neurologically-related deaths in the GP IIb/IIIa inhibitor group resulted from intracranial hemorrhages; there were no intracranial hemorrhages in the heparin-only group. There was 1 episode of extracranial bleeding in the GP IIb/IIIa inhibitor group treated with embolization. The incidences of significant puncture-site bleeding requiring transfusion were similar in the groups. Neurological complications following percutaneous carotid artery interventions have been relatively few. The neurological sequelae in carotid stent patients receiving glycoprotein IIb/IIIa inhibitors were more numerous and consequential, which suggests that the use of GP IIb/IIIa inhibitors in carotid stenting should be discouraged.

Follow-up of Stented Carotid Arteries by Doppler Ultrasound

OBJECTIVE Blood flow velocity (BFV) in the carotid artery is altered by stent placement. The significance of these alterations is unknown. In our experience, both standard BFV criteria for stenosis and customized criteria recommended by other authors have led to high rates of false-positive studies. We reviewed our experience with Doppler ultrasonography immediately after extracranial carotid artery stent placement to define criteria for restenosis by BFV. METHODS Complete carotid angiograms and BFV results were available for 114 patients treated between January 1998 and December 1999. Angiographic images obtained immediately after stent placement and at follow-up were measured for residual or recurrent stenosis by a blinded reviewer according to the North American Symptomatic Carotid Endarterectomy Trial method. Results of BFV studies obtained within 1 week of stent placement were interpreted by using two standard criteria (A, peak in-stent systolic velocity greater than 125 cm/s;B, internal carotid artery-to-common carotid artery ratio greater than 3.0) and two customized criteria (C, peak in-stent velocity greater than 170 cm/s;D, internal carotid artery-to-common carotid artery ratio greater than 2.0). The results of follow-up angiography and the most recent Doppler study were compared for nine patients. RESULTS On the basis of an examination of Doppler studies obtained immediately after stent placement, 36 patients met Criterion A for stenosis according to measured BFV (corresponding mean angiographic stenosis, 14.73 ± 18.45%), 3 patients met Criterion B (mean stenosis, 1.67 ± 2.89%), 8 patients met Criterion C (mean stenosis, 12.61 ± 13.18%), and 14 met Criterion D (mean stenosis, 7.98 ± 21.74%). No patient with Doppler criteria for significant stenosis had more than 50% residual stenosis. Three of nine patients who underwent follow-up angiography had stenosis of 50% or more; of these three patients, two underwent second angioplasty procedures. The peak in-stent systolic velocity or internal carotid artery-to-common carotid artery BFV ratio for each of the three patients with restenosis, but not for the six other patients, had increased by more than 80% since the immediate post-stenting Doppler study. CONCLUSION Strict BFV criteria for restenosis after carotid artery stenting are less reliable than change in BFV over time. An immediate post-stenting Doppler study must be obtained to serve as a reference value for future follow-up evaluation.

Follow-up of Stented Carotid Arteries by Doppler Ultrasound

Blood flow velocity (BFV) in the carotid artery is altered by stent placement. The significance of these alterations is unknown. In our experience, both standard BFV criteria for stenosis and customized criteria recommended by other authors have led to high rates of false-positive studies. We reviewed our experience with Doppler ultrasonography immediately after extracranial carotid artery stent placement to define criteria for restenosis by BFV. Complete carotid angiograms and BFV results were available for 114 patients treated between January 1998 and December 1999. Angiographic images obtained immediately after stent placement and at follow-up were measured for residual or recurrent stenosis by a blinded reviewer according to the North American Symptomatic Carotid Endarterectomy Trial method. Results of BFV studies obtained within 1 week of stent placement were interpreted by using two standard criteria (A, peak in-stent systolic velocity greater than 125 cm/s; B, internal carotid artery-to-common carotid artery ratio greater than 3.0) and two customized criteria (C, peak in-stent velocity greater than 170 cm/s; D, internal carotid artery-to-common carotid artery ratio greater than 2.0). The results of follow-up angiography and the most recent Doppler study were compared for nine patients. On the basis of an examination of Doppler studies obtained immediately after stent placement, 36 patients met Criterion A for stenosis according to measured BFV (corresponding mean angiographic stenosis, 14.73 +/- 18.45%), 3 patients met Criterion B (mean stenosis, 1.67 +/- 2.89%), 8 patients met Criterion C (mean stenosis, 12.61 +/- 13.18%), and 14 met Criterion D (mean stenosis, 7.98 +/- 21.74%). No patient with Doppler criteria for significant stenosis had more than 50% residual stenosis. Three of nine patients who underwent follow-up angiography had stenosis of 50% or more; of these three patients, two underwent second angioplasty procedures. The peak in-stent systolic velocity or internal carotid artery-to-common carotid artery BFV ratio for each of the three patients with restenosis, but not for the six other patients, had increased by more than 80% since the immediate post-stenting Doppler study. Strict BFV criteria for restenosis after carotid artery stenting are less reliable than change in BFV over time. An immediate post-stenting Doppler study must be obtained to serve as a reference value for future follow-up evaluation.

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...

Management of neurological complications of carotid artery stenting.

To review the neurological complications associated with extracranial carotid artery stenting and to preliminarily assess techniques used to manage these complications. 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. 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. 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.