Ultrasound criteria for severe in-stent restenosis following carotid artery stenting

PURPOSE: In-stent restenosis (ISR) is a known complication following carotid artery stenting (CAS). However, ultrasound criteria determining ISR are not well established. We evaluated alternative ultrasound velocity criteria for >70% ISR in our institution. METHODS: Clinical records of 256 patients undergoing 282 consecutive CAS procedures over a 42-month period were reviewed. Follow-up ultrasounds were available for analysis in 237 patients. Selective angiograms and repeat interventions were performed for >70% ISR. Ultrasound criteria including peak systolic velocity (PSV), end diastolic velocity (EDV), and internal carotid to common carotid artery ratios (ICA/CCA) were examined. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for PSV (200, 250, 300, 350, and 400 cm/s), EDV (70, 80, 90, 100 cm/s), and CCA/ICA (3, 3.5, 4, 4.5, 5). RESULTS: Twenty-two carotid angiograms were performed and 18 lesions had confirmations of >70% ISR in 11 patients including prior CEA in five patients and neck irradiation in two patients. Receiver operator characteristics (ROC) was analyzed for PSV, EDV, and CCA/ICA ratio. For 70% or greater angiographic ISR, PSV > 300 cm/s correlated to a 94% sensitivity, 50% specificity, 90% positive predictive value (PPV), and 67% negative predictive value (NPV); EDV > 90 cm/s correlated to an 89% sensitivity, 100% specificity, 100% PPV, and 67% NPV; and ICA/CCA > 4 had a 94.4% sensitivity, 75% specificity, 94% PPV, and 75% NPV. A significant color flow disturbance was detected in one patient who did not meet the aforementioned ultrasound velocity criteria. Further statistical analysis showed that an EDV of 90 cm/s provided the best discriminant value. CONCLUSION: Our study demonstrated that PSV > 300 cm/s, EDV > 90 cm/s, and ICA/CCA > 4 correlated well with >70% ISR. Although still rudimentary, these velocity criteria combined with color flow patterns can reliably predict severe ISR in our vascular laboratory. However, due to the relatively infrequent cases of severe ISR following CAS, a multicentered study is warranted to establish standard post-CAS ultrasound surveillance criteria for severe ISR.     

Risk factors for restenosis after carotid artery angioplasty and stenting

OBJECTIVES: With carotid artery stenting (CAS) becoming an ever-increasing procedure, we sought to determine risk factors for in-stent restenosis after CAS. METHODS: Consecutive patients undergoing CAS between January 2002 and October 2004 at a tertiary care hospital were retrospectively reviewed. Patient, filter, and stent selection were left to the discretion of the attending surgeon. High-risk patients were defined by significant comorbidities or a hostile neck (prior surgery or radiation, or both), and risk factor analysis was performed. In-stent restenosis was defined as >60%, and selective angiography was performed on patients with an in-stent restenosis >80% by duplex ultrasound imaging. RESULTS: Reviewed were 101 patients (55 men, 46 women) who underwent 109 CAS procedures. Comorbidities were typical for patients with atherosclerosis. In addition, 38% (n = 41) of procedures were performed in patients who had prior neck surgery, of which 29% (n = 32) had previous ipsilateral carotid endarterectomy. Seventeen patients (16%) had a history of neck cancer, and all had prior neck radiation. Median follow-up was 5 months (range, 0 to 30 months). Neurologic complications included three transient ischemic attacks (2.8%) and one nondisabling stroke (0.9%). There were two myocardial infarctions (1.9%) and no periprocedural deaths (30 days), for a combined stroke, myocardial infarction, and death rate of 2.9%. Asymptomatic in-stent restenosis developed in 12 carotids (11%), five of which required endovascular intervention, with a mean of 6 months to restenosis. Univariate Cox proportional hazard regression models were used to determine risk factors for the development of restenosis. Prior stroke, transient ischemic attack, amaurosis fugax, and prior neck cancer were all significant risk factors. When these significant risk factors from univariate analysis were put into multivariate analysis, however, the only marginally significant risk factor was prior neck cancer (P = .06). Kaplan-Meier analysis revealed a cumulative freedom from in-stent restenosis at 24 months of 88% +/- 6% in patients without neck cancer compared with 27% +/- 17% (P = .02) in patients with neck cancer. CONCLUSIONS: CAS has been shown to be safe and effective in high-risk patients, with minimal adverse events.     

Intrapatient comparison of restenosis between carotid artery angioplasty with stenting and carotid endarterectomy

AIM: Comparison of restenosis in patients who underwent both carotid artery angioplasty with stenting (CAS) and contralateral carotid endarterectomy (CEA). METHODS: From our CAS data registry (1998-present) all patients with a history of contralateral CEA at any other time were selected (n = 63). Mean age was 70.6, SD = 6.8 for CAS and 68.2, SD = 6.1 for CEA and symptomatic carotid artery stenosis was present in 24% of patients pre-CAS and 40% pre-CEA. All CEAs were primary interventions, 19% of CAS were secondary to restenosis after previous ipsilateral CEA. All patients were followed up prospectively with duplex at 1 year (CAS: n = 58, CEA: n = 59), 2 years (CAS: n = 44, CEA: n = 53), 3 years (CAS: n = 27, CEA: n = 41), and every year thereafter. Within each patient we compared restenosis (>50%) between CAS and CEA procedures. RESULTS: After a follow-up of 28.7 months for CAS (SD = 16.9) and 54.4 months for CEA (SD = 39.5) the rate of = or > 50% restenosis for CAS vs CEA at 1, 2, and 3 years was 23% vs 10%; 31% vs 19%; and 34 vs 24%, respectively (log rank P = NS). CONCLUSIONS: Our intrapatient comparison of patients who underwent both CAS and contralateral CEA did not reveal significant difference in restenosis between both procedures.     

Dealing with complications related to carotid artery stenting

This paper will describe the complications that can occur during and after carotid artery angioplasty and stenting. Etiology, prevention and treatment of procedure related complications will be dealt with.     

Surgical management of acute carotid thrombosis after carotid stenting: a report of three cases

We report three cases of symptomatic acute carotid thrombosis occurring after carotid artery stenting (CAS). CASE 1: A patient presented with crescendo transient ischemic attacks on the second day after CAS. Ultrasound images demonstrated incomplete in-stent thrombosis due to plaque protrusion. The urgent surgical procedure consisted of stent removal and carotid thromboendarterectomy. CASE 2: A case of complete thrombosis of a carotid stent occurred 4 days after implantation in a patient with essential thrombocythemia diagnosed by chance. The surgical strategy included stent removal and carotid thromboendarterectomy. CASE 3: Cardiac multiple embolisms in a patient with chronic atrial fibrillation caused concomitant leg ischemia and acute carotid stent occlusion 2 hours after CAS. Cerebral reperfusion was established by embolectomy, without removing the stent. At the same time, the right leg ischemia was resolved by a thromboembolectomy with a Fogarty catheter. These three cases demonstrate that acute thrombosis after carotid stenting can be managed successfully with emergent surgical intervention. Thromboendarterectomy with stent removal or in selected cases, simple thromboembolectomy, can minimize neurologic sequelae in patients suffering from acute post-stenting carotid thrombosis.     

Management of in-sent restenosis after carotid artery stenting in high-risk patients

BACKGROUND: Carotid artery stenting (CAS) has emerged as an acceptable treatment alternative in patients with carotid bifurcation disease. Although early results of CAS have been promising, long-term clinical outcomes remain less certain. We report herein the frequency, management, and clinical outcome of in-stent restenosis (ISR) after CAS at a single academic institution. METHODS: Clinical records of 208 CAS procedures in 188 patients with carotid stenosis of 80% or greater, including 48 (26.5%) asymptomatic patients, during a 42-month period were analyzed. Follow-up serial carotid duplex ultrasound scans were performed. Selective angiography and repeat intervention were performed when duplex ultrasound scans showed 80% or greater ISR. Treatment outcomes of ISR interventions were analyzed. RESULTS: Over a median 17-month follow-up, 33 (15.9%) ISRs of 60% or greater were found, according to the Doppler criteria. Among them, seven patients (3.4%) with a mean age of 68 years (range, 65-87 years) developed high-grade ISR (> or =80%), and they all underwent further endovascular interventions. Six patients with high-grade ISR were asymptomatic, whereas one remaining patient presented with a transient ischemic attack. Five of seven ISRs occurred within 12 months of CAS, and two occurred at 18 months' follow-up. Treatment indications for initial CAS in these seven patients included recurrent stenosis after CEA (n = 4), radiation-induced stenosis (n = 1), and high-cardiac-risk criteria (n = 2). Treatment modalities for ISR included balloon angioplasty alone (n = 1), cutting balloon angioplasty alone (n = 4), cutting balloon angioplasty with stent placement (n = 1), and balloon angioplasty with stent placement (n = 1). Technical success was achieved in all patients, and no periprocedural complications occurred. Two patients with post-CEA restenosis developed restenosis after ISR interventions, both of whom were successfully treated with cutting balloon angioplasty at 6 and 8 months. The remaining five patients showed an absence of recurrent stenosis or symptoms during a mean follow-up of 12 months (range, 3-37 months). By using the Kaplan-Meier analysis, the freedom from 80% or greater ISR after CAS procedures at 12, 24, 36, and 42 months was 97%, 97%, 96%, and 94%, respectively. CONCLUSIONS: Our study showed that ISR after CAS remains uncommon. Successful treatment of ISR can be achieved by endovascular interventions, which incurred no instance of periprocedural complications in our series. Patients who developed ISR after CEA were likely to develop restenosis after IRS intervention. Diligent ultrasound follow-up scans are important after CAS, particularly in patients with post-CEA restenosis.     

Prosthetic bypass for restenosis after endarterectomy or stenting of the carotid artery

Objective

The objective of this study was to evaluate the results of prosthetic carotid bypass (PCB) with polytetrafluoroethylene (PTFE) grafts as an alternative to carotid endarterectomy (CEA) in treatment of restenosis after CEA or carotid artery stenting (CAS).

Late outcomes of carotid artery stenting: a critical review

The role of carotid artery stenting (CAS) as an alternative to carotid endarterectomy for the treatment of extracranial carotid occlusive disease for stroke prevention continues to evolve. Although technical and device refinements aimed at making CAS safer continue to this day, safety as measured by 30-day and 1-year outcomes has been the primary recipient of regulatory and practice attention. Relatively less emphasis has been placed on the incidence of recurrent stenosis after CAS and the efficacy of CAS in late stroke prevention. Data on late outcomes of CAS, including factors of potential influence, have been emerging and are addressed in this review.     

In-stent restenosis of innominate artery with critical stenosis of right internal carotid artery

A lady with aortitis syndrome developed in-stent restenosis (ISR) of the innominate artery stent and critical stenosis of right internal carotid artery. The therapeutic challenge was gaining access to the carotid vessel, after treating the innominate artery ISR and all the while using distal protection to circumvent potential cerebral embolism. Percutaneous transluminal angioplasty (PTA) with or without stenting is a safe therapeutic option for re-vascularization of the supra aortic vessels. In the event of re-stenosis, re-treatment with PTA and stenting is safe. Ample evidence-base exists now for carotid artery stenting (CAS) in preference to carotid endarterectomy in patients with stenotic lesions of the carotid vessels.     

Incidence and risk factors for medical complications after carotid artery stenting

OBJECTIVE: Carotid angioplasty and stenting (CAS) is being evaluated as an alternative to carotid endarterectomy for the treatment of carotid artery stenosis; however, to date little is known about the incidence of medical complications after CAS. The goal of this study was to determine the frequency of, and to identify potential clinical risk factors for, the development of medical complications after CAS. METHODS: Medical complications that occurred < or = 30 days after CAS in 327 consecutive patients (241 men, 86 women; mean age, 69 +/- 9 years; range, 45 to 90 years) treated for symptomatic (n = 182, 56%) or asymptomatic (n = 145, 44%) carotid artery stenosis were recorded. The effect of clinical characteristics on the subsequent development of medical complications was analyzed by logistic regression. RESULTS: Fifty-one patients (15%) had 62 medical complications: 3 (0.9%) myocardial infarctions, 3 (0.9%) cardiac arrhythmias, 4 (1.2%) episodes of angina pectoris, 3 (0.9%) episodes of symptomatic hypertension, 16 (4.9%) episodes of symptomatic hypotension, 10 (3.1%) chest infections, 9 (2.7%) had periods of confusion, 5 (1.5%) had urinary retention, and 9 (2.7%) urinary tract infections. One chest infection was fatal and 16 complications prolonged the intensive care unit monitoring period > 24 hours. Advanced age (odds ratio [OR], 1.1; 95% confidence interval [CI], 1.05 to 1.14) and a symptomatic carotid stenosis (OR, 2.1; 95% CI, 1.07 to 4.1) independently predicted the occurrence of medical complications. CONCLUSION: Although life-threatening or fatal non-neurologic events were uncommon in this series, the overall incidence of medical complications after CAS might be higher than currently anticipated. Older and symptomatic patients are at the highest risk, and these subgroups should be monitored closely.     

Perioperative management for a case of carotid artery stenting

A 70-year-old male patient with severe cardiac dysfunction underwent carotid artery stenting for severe left carotid artery stenosis under monitored anesthetic care. He was sedated with propofol and fentanyl, and was monitored with ECG, pulse-oximeter and direct blood pressure measurement. He breathed spontaneously without severe hypoxia during the procedure. Followed by insertion of transient ventricular pacing wire against expected severe bradycardia, a guidewire was introduced into left internal carotid artery lesion via the right femoral artery. Soon after dilating the stenotic portion with a ballon catheter, sudden hypotension and bradycardia were recognized, which were successfully managed with bolus injections of vasoconstrictors and atropine sulphate. Even after stenting, hypotension continued for two days in spite of continuous administration of dopamine. Postoperative examination showed that the blood flow of the left carotid artery was doubled. Two weeks after the operation, he was discharged uneventfully.     

Surgical management of extracranial carotid artery aneurysms

Between 1982 and 1991 we performed eight operations on seven patients with carotid artery aneurysms. Their mean age was 52.8 years (range: 20–67 years). Five aneurysms were atherosclerotic, one was associated with Marfan's syndrome, and two were pseudoaneurysms, one occurring after Dacron patch angioplasty and the other due to tuberculosis. Seven aneurysms were treated electively; one patient underwent an emergency surgical procedure. In one case, the internal carotid artery was ligated. Seven operations were reconstructive. No intraluminal shunt was used. No perioperative deaths occurred. Regressive hemiparesis and ipsilateral Horner's syndrome developed in one patient. The follow-up period ranged from six months to nine and a half years. One patient died of myocardial infarction three months after surgery.     

Surgical management of the occluded carotid artery

Of 36 patients with symptomatic total occlusion of the common carotid and/or internal carotid arteries, ipsilateral operation was performed in 20. Twenty-eight patients had occlusion of the internal carotid artery, four of the common carotid alone, and four had occlusion of both vessels. Thirteen patients had completed stroke. Noninvasive examination erroneously suggested internal carotid patency in three patients. Of six patients with occluded common carotid arteries, two underwent thromboendarterectomy, two underwent saphenous vein bypass, and two underwent Dacron graft bypass procedures. Five patients underwent attempted internal carotid thromboendarterectomy and three patients underwent external carotid endarterectomy. Seven patients underwent primary temporal to middle cerebral bypass procedures. There were no perioperative deaths and no patients had permanent neurologic deterioration. There were two postoperative complications. At follow-up 1 to 43 months after operation, five of six patients who had undergone common carotid revascularization had improved neurologically while other treatment groups had no definite improvement. Revascularization of an occluded common carotid artery is a safe procedure that successfully alleviates symptoms of cerebral ischemia. Internal carotid disobliteration and external carotid endarterectomy alone provide limited neurovascular benefit. Benefits of extracranial-to-intracranial bypass were not apparent from this small series.     

Surgical management of extracranial carotid artery aneurysms

Extracranial carotid artery aneurysms are uncommon and not much is known about them. The purpose of this study is to report the authors’ surgical experience and present a review of this entity. This single institution experience shows that resection of these aneurysms and restoration of flow can be accomplished using a number of surgical techniques with relatively low morbidity and mortality. Endovascular techniques are also increasingly being considered in the repair of these aneurysms, although long‐term data from such techniques are not currently available.     

Carotid endarterectomy performed after carotid artery restenosis following stent migration

Right carotid occlusion and left carotid stenosis were determined in a patient who had undergone a cerebrovascular accident. We performed a carotid endarterectomy for the high-risk patient who developed middle cerebral artery occlusion during stenting and a restenosis owing to stent migration.