Carotid stenting for severe radiation-induced extracranial carotid artery occlusive disease

Imaging Characteristics and Reintervention in Patients After Radiation Induced Carotid Artery Stenting

OBJECTIVE

To evaluate and describe the radiographic imaging findings in a series of patients who underwent re-intervention after radiation-induced carotid artery stenting (RICAS).

METHODS

Retrospective review of patients with prior RICAS and subsequent re-intervention.

RESULTS

We describe ten patients including eight male and two female patients with twelve re-interventions due to prior diagnosed radiation induced carotid artery stenosis (RICS) and subsequent stenting during the period 2000-2019. The rate of re-intervention was found to be 10%. The pattern of stenosis is unique to this patient population including specifically long-segment stenosis, proximal and distal to the stent location, which tends not to occur in the atherosclerotic patient population.

CONCLUSION

Careful surveillance after RICAS is necessary to assess for the risk and the unusual pattern of stenosis to offer re-intervention in this high-risk patient population.

Late Outcomes of Carotid Artery Stenting for Radiation Therapy-Induced Carotid Stenosis

PURPOSE

Carotid artery stenting (CAS) appears as a promising alternative treatment to carotid endarterectomy for radiation therapy (RT)-induced carotid stenosis. However, this is based on a poor level of evidence studies (small sample size, primarily single institution reports, few long-term data). The purpose of this study was to report the long-term outcomes of a multicentric series of CAS for RT-induced stenosis.

METHODS

All CAS for RT-induced stenosis performed in 11 French academic institutions from 2005 to 2017 were collected in this retrospective study. Patient demographics, clinical risk factors, elapsed time from RT, clinical presentation and imaging parameters of carotid stenosis were preoperatively gathered. Long-term outcomes were determined by clinical follow-up and duplex ultrasound. The primary endpoint was the occurrence of cerebrovascular events during follow-up. Secondary endpoints included perioperative morbidity and mortality rate, long-term mortality rate, primary patency, and target lesion revascularization.

RESULTS

One hundred and twenty-one CAS procedures were performed in 112 patients. The mean interval between irradiation and CAS was 15 ± 12 years. In 31.4% of cases, the lesion was symptomatic. Mean follow-up was 42.5 ± 32.6 months (range 1-141 months). The mortality rate at 5 years was 23%. The neurologic event-free survival and the in-stent restenosis rates at 5 years were 87.8% and 38.9%, respectively. Diabetes mellitus (p=0.02) and single postoperative antiplatelet therapy (p=0.001) were found to be significant predictors of in-stent restenosis. Freedom from target lesion revascularization was 91.9% at 5 years.

CONCLUSION

This study showed that CAS is an effective option for RT-induced stenosis in patients not favorable to carotid endarterectomy. The CAS was associated with a low rate of neurological events and reinterventions at long-term follow-up.

Outcomes of carotid artery stenting in patients with radiation arteritis compared with those with atherosclerotic disease

OBJECTIVE

Head and neck malignancies are often treated with radiotherapy (RT). Nearly 80% of patients who have undergone RT will develop carotid radiation arteritis to some degree and 29% will develop stenosis >50%. Surgery in a radiated neck has higher rates of complications, and carotid artery stenting (CAS) has become the primary therapy. The outcomes for CAS in patients with radiation arteritis have not been rigorously evaluated. The objective of the present study was to evaluate the differences in perioperative outcomes, restenosis rates, the need for reintervention, and freedom from mortality between RT patients and patients with atherosclerotic disease who had undergone CAS.

METHODS

The national Vascular Quality Initiative CAS dataset from 2016 to 2019 comprised the sample for analyses (n = 7343). The primary independent variable was previous head and/or neck RT. The primary endpoint was the interval to mortality. The secondary endpoints were the cumulative incidence of restenosis (>50% and >70% by duplex ultrasound) and reintervention. We also examined the following secondary perioperative endpoints: myocardial infarction, in-hospital mortality (death before discharge), neurologic events, ipsilateral stroke, and contralateral stroke. Kaplan-Meier and multivariable Cox proportional hazard models were used to assess for mortality, and cumulative incidence function estimates were used for the nonfatal endpoints.

RESULTS

Of the 7218 patients, 1199 (17%) had undergone prior RT. We found a significant difference in the 3-year estimates of mortality for those with and without prior RT (9.4% and 7.5%, respectively; P = .03). Furthermore, on adjusted analysis, we observed a 58% increase in the risk of mortality for those with prior RT (adjusted hazard ratio, 1.58; 95% confidence interval, 1.13-2.21). We did not observe any differences in the risk of perioperative complications (myocardial infarction, in-hospital mortality, ipsilateral or contralateral stroke), restenosis (>50% or >70%), or reintervention for the prior RT group compared with those without RT.

CONCLUSIONS

The CAS patients with RT had significantly greater mortality at all time points compared with those without RT, even after adjusting for other covariates. No significant difference was found in the incidence of perioperative complications, reintervention, or restenosis between the two groups. The present study is unique because of the large sample size and length of follow-up. The results suggest that for this high-risk group, CAS provides the same patency as it does for atherosclerotic carotid stenosis and avoids potentially morbid cranial nerve injury and wound healing complications.

Radiation-Induced Vascular Disease-A State-of-the-Art Review

Since the 1990s, there has been a steady increase in the number of cancer survivors to an estimated 17 million in 2019 in the US alone. Radiation therapy today is applied to a variety of malignancies and over 50% of cancer patients. The effects of ionizing radiation on cardiac structure and function, so-called radiation-induced heart disease (RIHD), have been extensively studied. We review the available published data on the mechanisms and manifestations of RIHD, with a focus on vascular disease, as well as proposed strategies for its prevention, screening, diagnosis, and management.

Higher Risk for Reintervention in Patients after Stenting for Radiation-Induced Internal Carotid Artery Stenosis: A Single-Center Analysis and Systematic Review

BACKGROUND

This study aimed to review short- and long-term outcomes of all carotid artery stenting (CAS) in patients with radiation-induced (RI) internal carotid artery (ICA) stenosis compared with patients with atherosclerotic stenosis (AS).

METHODS

We performed a single-center, multisite case-control study of transfemoral carotid artery intervention in patients stented for RI or AS. Cases of stented RI carotid arteries were identified using a CAS database covering January 2000 to December 2019. These patients were randomly matched 2:1 with stented patients because of AS by age, sex, and year of CAS. A conditional logistic regression model was performed to estimate the odds of reintervention in the RI group. Finally, a systematic review was performed to assess the outcomes of RI stenosis treated with CAS.

RESULTS

There were 120 CAS in 113 patients because of RI ICA stenosis. Eighty-nine patients (78.8%) were male, and 68 patients (60.2%) were symptomatic. The reasons for radiation included most commonly treatment for diverse malignancies of the head and neck in 109 patients (96.5%). The mean radiation dose was 58.9 ± 15.6 Gy, and the time from radiation to CAS was 175.3 ± 140.4 months. Symptoms included 31 transient ischemic attacks (TIAs), 21 strokes (7 acute and 14 subacute), and 17 amaurosis fugax. The mean National Institutes of Health Stroke Scale in acute strokes was 8.7 ± 11.2. In asymptomatic patients, the indication for CAS was high-grade stenosis determined by duplex ultrasound. All CAS were successfully completed. Reinterventions were more frequent in the RI ICA stenosis cohort compared with the AS cohort (10.1% vs. 1.4%). Reinterventions occurred in 14 vessels, and causes for reintervention were restenosis in 12 followed by TIA/stroke in two vessels. On conditional regression modeling, patients with RI ICA stenosis were at a higher risk for reintervention (odds ratio = 7.1, 95% confidence interval = 2.1-32.8; P = 0.004). The mean follow-up was 33.7 ± 36.9 months, and the mortality across groups was no different (P = 0.12).

CONCLUSIONS

In our single-center, multisite cohort study, patients who underwent CAS for RI ICA stenosis experienced a higher rate of restenosis and a higher number of reinterventions compared with CAS for AS. Although CAS is safe and effective for this RI ICA stenosis cohort, further data are needed to reduce the risk of restenosis, and close patient surveillance is warranted. In our systematic review, CAS was considered an excellent alternative option for the treatment of patients with RI ICA stenosis. However, careful patient selection is warranted because of the increased risk of restenosis on long-term follow-up.

Peripheral Artery Disease and Stroke

Peripheral artery disease (PAD) and stroke can occur as vascular complication of anticancer treatment. Although the mechanisms, monitoring, and management of cardiotoxicities have received broad attention, vascular toxicities remain often underrecognized. In addition, the development of new chemotherapeutic drugs bears the risk of vasotoxicities that are yet to be identified and may not be realized with short-term follow-up periods. The propensity to develop PAD and/or stroke reflects the complex interplay between patient's baseline risk and preexisting vascular disease, particularly hypertension and diabetes, while evidence for genetic predisposition is increasing. Chemotherapeutic agents with a prominent vascular side effect profile have been identified. Interruption of vascular endothelial growth factor (VEGF) inhibitors (VEGFIs) signaling (i.e., bevacizumab) is associated with vascular toxicity and clinical sequelae such as hypertension, stroke, and thromboembolism beyond acute coronary syndromes. Cisplatin and 5-fluorouracil are the main drugs involved in the stroke risk. In addition, circulating concentrations of VEGF are reduced by cyclophosphamide administered at continuous low doses, which might underpin some of the observed vascular toxicity, such as stroke, as seen in patients treated with VEGF inhibitors. The risk of stroke is also increased after treatment with anthracyclines that can induce endothelial dysfunction and increase arterial stiffness. Proteasome inhibitors ( bortezomib and carfilzomib) and immunomodulatory agents (thalidomide, lenalidomide, and pomalidomide), approved for use in multiple myeloma, carry a black box warning for an increased risk of stroke. Finally, head-and-neck radiotherapy is associated with a doubled risk of cerebrovascular ischemic event, especially if exposure occurs in childhood. The mechanisms involved in radiation vasculopathy are represented by endothelial dysfunction, medial necrosis, fibrosis, and accelerated atherosclerosis. However, BCR-ABL tyrosine kinase inhibitor (TKI), used for the treatment of chronic myeloid leukemia (CML), is the main antineoplastic drugs involved in the development of PAD. In particular, second- and third-generation TKIs, such as nilotinib and ponatinib, while emerging as a potent arm in contrasting CML, are associated with a higher risk of PAD development rather than traditional imatinib. Factors favoring vascular complication are the presence of traditional cardiovascular risk factors (CVRF) and predisposing genetic factors, high doses of BCR-ABL TKIs, longer time of drug exposure, and sequential use of potent TKIs. Therefore, accurate cardiovascular risk stratification is strongly recommended in patient candidate to anticancer treatment associated with higher risk of vascular complication, in order to reduce the incidence of PAD and stroke through CVRF correction and selection of appropriate tailored patient strategy of treatment. Then, a clinical follow-up, eventually associated with instrumental evaluation through vascular ultrasound, should be performed.

Carotid Stenting for Radiation-Induced Extracranial Carotid Artery Occlusive Disease: Efficacy and Midterm Outcomes

Purpose:

To investigate the immediate and midterm results of carotid stenting for severe radiation-induced extracranial carotid artery disease.

Methods:

Between April 1998 and May 2002, 16 patients (15 men; mean age 64±8 years, range 48–72) presented with 18 severe radiation-induced carotid stenoses in the internal carotid artery (n=3), common carotid artery (n=7), and both vessels (n=8). Thirteen (76%) patients were symptomatic; the mean degree of carotid stenosis was 85%±10% (range 70%–95%). An independent neurological specialist assessed perioperative neurological complications before and after treatment. The patients were followed prospectively for at least 12 months by clinical examination and serial duplex ultrasound scanning. Restenosis was defined as a diameter reduction >50%.

Results:

Of 18 stent procedures attempted (2 staged), 1 was abandoned owing to failure to pass the guidewire across a tight lesion (94% technical success by intent to treat). In the 17 successfully completed procedures, 17 Wallstents and 4 SMART stents were deployed with satisfactory anatomical results. One postoperative stroke occurred as a result of thromboembolism to the ipsilateral middle cerebral artery and led to hospital death (5.9% combined stroke and death rate). One transient ischemic attack occurred (11.6% neurological event rate). With a median 30-month follow-up (range 5–55), 3 (17.6%) recurrent stenoses (>50%) were detected on duplex scan; 1 repeat angioplasty was performed. No new neurological event has been detected.

Conclusions:

Carotid stenting may be performed in patients with irradiation-induced carotid stenosis with acceptable risks and midterm durability.

SCAI Expert consensus statement: Evaluation, management, and special considerations of cardio-oncology patients in the cardiac catheterization laboratory (endorsed by the cardiological society of india, and sociedad Latino Americana de Cardiologıa intervencionista)

In the United States alone, there are currently approximately 14.5 million cancer survivors, and this number is expected to increase to 20 million by 2020. Cancer therapies can cause significant injury to the vasculature, resulting in angina, acute coronary syndromes (ACS), stroke, critical limb ischemia, arrhythmias, and heart failure, independently from the direct myocardial or pericardial damage from the malignancy itself. Consequently, the need for invasive evaluation and management in the cardiac catheterization laboratory (CCL) for such patients has been increasing. In recognition of the need for a document on special considerations for cancer patients in the CCL, the Society for Cardiovascular Angiography and Interventions (SCAI) commissioned a consensus group to provide recommendations based on the published medical literature and on the expertise of operators with accumulated experience in the cardiac catheterization of cancer patients.

Relationship between histologic features and outcomes of carotid revascularization for radiation-induced stenosis

OBJECTIVE

This study aimed to elucidate the relationships between preoperative carotid imaging results, histologic characteristics, and surgical treatment outcomes of radiation-induced carotid stenosis (RICS), using control subjects without RICS for comparison.

METHODS

We retrospectively reviewed records of 17 patients who underwent carotid revascularization for 22 instances of RICS, including 10 cases of carotid artery stenting (CAS), 11 cases of carotid endarterectomy (CEA), and 1 case of CEA with retrograde CAS, between July 2004 and April 2013. The controls were 475 patients with no history of radiation therapy who underwent carotid revascularization in a similar period. Preoperative magnetic resonance imaging (MRI), ultrasonography (US), and computed tomography angiography results were correlated with outcomes of histologic analysis of CEA specimens. End points included ipsilateral and contralateral stroke, myocardial infarction, restenosis, in-stent thrombosis, and target lesion revascularization.

RESULTS

Vulnerable plaques on carotid MRI (86% vs 64.2%; P = .010) and mobile (27% vs 8.0%; P = .008) and ulcerative (50% vs 15.8%; P < .001) plaques on US were more frequent in the RICS group. All revascularization procedures were successful, and no occlusion occurred. Adverse events in the CAS group, including one minor stroke and one transient ischemic attack within 30 days as well as five ipsilateral neurologic events after 30 days, including three minor strokes and two transient ischemic attacks, were significantly more frequent than in the CEA group. All three cases of late ipsilateral stroke displayed vulnerable plaque on preoperative MRI and late in-stent thrombosis or restenosis on US.

CONCLUSIONS

Our radiologic and histologic analyses revealed that advanced RICS is often accompanied by formation of vulnerable plaque. CEA can prevent undesirable late outcomes in such cases.

Vascular Reconstruction for Radiation-induced Bilateral Internal Carotid Artery Occlusion and Unilateral External Carotid Artery Stenosis by a Combination of Surgical and Endovascular Method: Case Report

We present a case of a 63-year-old male presenting with right hemiparesis and diagnosed as cerebral infarction. He had a previous history of left pharyngeal carcinoma, which was treated by radial dissection and radiation therapy 10 years before. Magnetic resonance imaging (MRI) showed multiple cerebral infarction in the bilateral cerebral hemisphere, predominantly on the left. Cerebral angiography showed occlusion of bilateral internal carotid arteries and severe stenosis at the orifice of the left external carotid artery (ECA). Single photon emission tomography (SPECT) showed reduced cerebral blood flow and decreased cerebral vascular reserve in the bilateral anterior cerebral artery and left middle cerebral artery territories. He was successfully treated by a combination of carotid stenting for the left ECA and left superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. He did not have further ischemic symptom for more than 2 years. Radiation-induced carotid vasculopathy often involves multiple arteries and treatment is often complex and difficult. Safer and less invasive treatment strategy should be considered using both endovascular and direct surgery.

Conjoined stent technique for radiation induced long segment carotid stenosis and pseudoaneurysm

Radiation induced carotid stenosis (RICS) is known but challenging complication of head and neck irradiation. Endovascular revascularization is preferred treatment modality than surgical revascularization. Sometimes endovascular treatment may be difficult in view of long segment of stenosis and associated pseudoaneurysm. We report a unique technique of carotid stenting named as "conjoined stent technique" in a challenging case of RICS with long segment of stenosis and pseudoaneurysm. In this technique we overlapped distal end of one stent with proximal end of second stent to occlude pseudoaneurysm. "Conjoined stent technique" may be viable option in case of long segment of RICS with associated pseudoaneurysm and alternative to flow diverters in extracranial carotid pseudoaneurysm.

Periprocedural outcomes after surgical revascularization and stenting for postradiotherapy carotid stenosis

BACKGROUND

Treatment of head and neck malignancy commonly involves radiotherapy, which is associated with the development of carotid artery stenosis. There is little evidence to guide clinicians on how to intervene in significant postradiotherapy carotid stenosis. This systematic review collated data pertaining to perioperative outcomes of carotid artery surgery and carotid stenting in postradiotherapy carotid stenosis to aid the clinical decision-making process.

METHODS

A systematic review of the literature, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2009 guidelines, was performed. We screened 575 articles related to carotid artery surgery or stenting in postradiotherapy carotid stenosis, from which 21 studies were included for quantitative analysis. The primary outcome was stroke or death ≤ 30 days of the procedure. Secondary outcomes included cranial nerve injury, restenosis, stroke, and death at >30 days.

RESULTS

Nine publications recorded 211 surgical procedures in 179 patients. In symptomatic patients, the 30-day mortality rate was 2.6% and the stroke or death rate was 2.7%. In asymptomatic patients, the 30-day mortality rate was 0% and the stroke or death rate was 1.1%. Permanent cranial nerve palsy was experienced by 0.6% of patients. Twelve publications recorded 510 carotid artery stenting procedures in 482 patients. In symptomatic patients, the 30-day mortality rate was 5.1%, and the stroke or death rate was 5.1%. In asymptomatic patients, the 30-day mortality rate was 1.4%, and the stroke or death rate was 2.1%. There was no statistically significant difference in 30-day stroke or death rate between surgical revascularization and carotid artery stenting in all (odds ratio [OR], 0.54; 95% confidence interval [CI] 0.17-1.70; P = .43), symptomatic (OR, 0.52; 95% CI, 0.14-1.98; P = .38), or asymptomatic patients (OR, 0.55; 95% CI, 0.06-5.42; P = .99).

CONCLUSIONS

The published outcomes from high-volume centers demonstrate that surgical revascularization and stenting are both technically feasible in postradiotherapy carotid stenosis and have similar safety profiles to nonirradiated necks. Radiation should therefore not be considered a contraindication to surgical intervention.

Ischemic stroke and transient ischemic attack after head and neck radiotherapy: a review

BACKGROUND AND PURPOSE

Cerebrovascular disease can complicate head and neck radiotherapy and result in transient ischemic attack and ischemic stroke. Although the incidence of radiation vasculopathy is predicted to rise with improvements in median cancer survival, the pathogenesis, natural history, and management of the disease are ill defined.

METHODS

We examined studies on the epidemiology, imaging, pathogenesis, and management of medium- and large-artery intra- and extra-cranial disease after head and neck radiotherapy. Controlled prospective trials and larger retrospective trials from the last 30 years were prioritized.

RESULTS

The relative risk of transient ischemic attack or ischemic stroke is at least doubled by head and neck radiotherapy. Chronic radiation vasculopathy affecting medium and large intra- and extra-cranial arteries is characterized by increasing rates of hemodynamically significant stenosis with time from radiotherapy. Disease expression is the likely consequence of the combined radiation insult to the intima-media (accelerating atherosclerosis) and to the adventitia (injuring the vasa vasorum). Optimal medical treatment is not established. Carotid endarterectomy is confounded by the need to operate across scarred tissue planes, whereas carotid stenting procedures have resulted in high restenosis rates.

CONCLUSIONS

Head and neck radiotherapy significantly increases the risk of transient ischemic attack and ischemic stroke. Evidence-based guidelines for the management of asymptomatic and symptomatic (medium- and large-artery) radiation vasculopathy are lacking. Long-term prospective studies remain a priority, as the incidence of the problem is anticipated to rise with improvements in postradiotherapy patient survival.

Predictors of carotid stent restenosis

OBJECTIVES

We sought to determine the predictors of restenosis after carotid artery stenting and report alternatives for its management.

BACKGROUND

Carotid artery stenting has been increasingly accepted as an alternative to carotid endarterectomy (CEA). Predictors of carotid stent restenosis have not been firmly established, and management of restenotic lesions can be challenging.

METHODS

A retrospective, single-center review was conducted of 399 carotid stent procedures in 363 patients over 9 years, with a mean follow-up of 24 months (range 6-99 months). Clinical variables included age, gender, symptoms, hypertension, diabetes, tobacco use, renal insufficiency, coronary artery disease, hyperlipidemia, peripheral vascular disease, history of CEA, and history of neck radiation (XRT). Angiographic variables included reference vessel diameter, lesion length, post-stenting residual stenosis, stent diameter, type of stent, and number of stents.

RESULTS

Overall, restenosis occurred in 15 patients (3.8%). However, the restenosis occurred in 7 of 35 (20%) patients who had previous XRT, 6 of 57 (10.5%) patients who had previous CEA, and 2 of 9 (22%) patients who previously had both CEA and XRT. The only analyzed variables that were significantly associated with an increased risk of restenosis were previous CEA (OR 4.28, P = 0.008) or XRT (OR 11.3, P <or=<or= 0.0001). Restenosis was most often asymptomatic and detected at routine ultrasound follow-up. Restenotic lesions were successfully treated in 11/11 cases with angioplasty (27%) or stenting (73%). Four patients that are asymptomatic are being monitored closely with ultrasound. No patients required surgical therapy for restenosis.

CONCLUSIONS

Restenosis after carotid stenting is uncommon; however, patients with previous CEA or XRT are at increased risk. Restenotic lesions may be safely treated with further percutaneous interventions.

Radiation arteritis: A contraindication to carotid stenting?

BACKGROUND

Carotid artery stenting (CAS) for high-risk anatomic lesions is accepted practice. Neck irradiation and radiotherapy-induced arteritis are common indications. The clinical outcomes of CAS for radiation arteritis have been poorly defined.

METHODS

A prospective database of patients undergoing CAS at a tertiary referral academic medical center was maintained from 1999 to 2006. Patients undergoing primary carotid artery stenting for significant atherosclerotic (ASOD) and radiotherapy (XRT)-induced occlusive disease were analyzed. Life-table analyses were performed to assess time-dependent outcomes. Cox proportional hazard analysis or Fisher's exact test was performed to identify factors associated with outcomes. Data are presented as the mean +/- SEM unless otherwise indicated.

RESULTS

During the study period, 150 patients underwent primary CAS, 75% with embolic protection. Fifty-eight percent were symptomatic. One hundred twenty-seven (85%) were treated for ASOD, and 23 (15%) had XRT. The 30-day all-cause mortality rate was 1% for ASOD and 0% for XRT (P = NS); overall survival at 3 years was equivalent. There was no significant difference in major adverse event rates as defined by the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial between the groups. The 3-year neurologic event-free rate was 85% for ASOD and 87% for XRT (P = NS). Late asymptomatic occlusions were seen only in XRT patients. The 3-year freedom from restenosis rate was significantly worse for the XRT group, at 20%, vs 74% for the ASOD group (P < .05). Likewise, the 3-year patency rate was also worse for the XRT group, at 91%, vs 100% for ASOD by Kaplan-Meier analysis (P < .05). No factor was predictive of occlusion or stenosis by Cox proportional hazards analysis.

CONCLUSION

CAS for radiation arteritis has poor long-term anatomic outcome and can present with late asymptomatic occlusions. These findings suggest that these patients require closer postoperative surveillance and raise the question of whether CAS is appropriate for carotid occlusive lesions caused by radiation arteritis.

Complications and Follow-up after Unprotected Carotid Artery Stenting

PURPOSE

This prospective study was undertaken to determine the success rate, complications, and outcome of carotid artery stenting (CAS) without the use of cerebral protection devices.

METHODS

During 12 months, 94 high-grade stenoses of the carotid artery in 91 consecutive patients were treated. Sixty-six (70%) of the stenoses were symptomatic and 28 (30%) were asymptomatic.

RESULTS

In all 94 carotid stenoses CAS was successfully performed. During the procedure and within the 30 days afterwards, there were 2 deaths and 3 major strokes in the 66 symptomatic patients, resulting in a combined death and stroke rate of 5 of 66 (7%). Only one of these complications, a major stroke, occurred during the procedure. In the 6-month follow-up, one additional major stroke occurred in a originally symptomatic patient resulting in a combined death and stroke rate of 6 of 66 (10%) for symptomatic patients at 6 months. No major complications occurred in asymptomatic patients during the procedure or in the 6-month follow-up period. At 6 months angiographic follow-up the restenosis rate with a degree of >50% was 3 of 49 (6%) and the rate with a degree of >or=70% was 1 of 49 (2%).

CONCLUSIONS

Cerebral embolization during CAS is not the only cause of the stroke and death rate associated with the procedure. The use of cerebral protection devices during the procedure may therefore not prevent all major complications following CAS.

Protected stent-assisted angioplasty in radiation-induced carotid artery stenosis

OBJECTIVE

The surgical treatment of radiation-induced carotid stenosis is challenging and presents a high rate of complications. This has led several investigators to propose stent-assisted angioplasty as the treatment of choice for this condition. The aim of this study is to evaluate the potential risks of intra-procedural embolic stroke in this setting using cerebral protection devices.

METHODS

We describe our recent experience in the endovascular treatment by means of stent-assisted angioplasty with the aid of a filter cerebral protection device of eight patients presenting with radiation-induced carotid stenosis.

RESULTS

Procedural success, defined as residual stenosis of less than 30% was obtained in all cases. The mean percentage stenosis was reduced from mean 80+/-6.3% (range 70-90%) to 13+/-4% (range 10-20%). Predilation was performed in five cases, post-dilation in all the cases. Mild-to-moderate bradycardia while inflating the balloon was present in three cases and was severe in one case. No patient sustained myocardial infarction, stroke or TIA during the procedure or hospital stay. During a mean clinical follow-up of 16+/-7.3 months (range 5-25) there were no neurological events. On sonographic follow-up, no patient presented in-stent de novo stenosis.

DISCUSSION

Carotid angioplasty with cerebral protection can be performed safely in radiation-induced carotid stenosis with a high technical success rate. With the recent innovations and improvements in angioplasty technique, its indications and results will have to be redefined. Given the complexity and complications of surgical approaches for this condition, and the encouraging results obtained with endovascular techniques, carotid angioplasty emerges as the preferred treatment option.

Carotid artery stenting with routine cerebral protection in high-risk patients

BACKGROUND

Carotid artery stenting has emerged as an alternative treatment modality in carotid occlusive disease. This study examined our experience of carotid stenting with routine cerebral embolization protection in high-risk patients.

METHODS

Clinical variables and treatment outcome of high-risk patients who underwent carotid stenting with neuroprotection were analyzed during a 26-month period.

RESULTS

Sixty-eight high-risk patients with 72 carotid artery stenoses were treated. Procedural success was achieved in 70 cases (97%), and symptomatic lesions existed in 17 (24%) patients. Monorail Wallstents stents were used in all cases. Neuroprotective devices used were PercuSurge (28%) and Filterwire (72%). There was no periprocedural mortality or neuroprotective device-related complications. The 30-day stroke and death rate was 2.7%, and the overall complication rate was 6.9%. All stented vessels remained patent during the follow-up period (mean 15.3 +/- 4.2, range 1 to 23 months). Two asymptomatic in-stent restenosis (3%) occurred at 6 and 8 months, which were both successfully treated with balloon angioplasty.

CONCLUSIONS

Our study showed that percutaneous carotid stenting with routine use of a cerebral protection device is a feasible and effective treatment in high-risk patients with carotid occlusive disease.

Concomitant coronary and multiple arch vessel stenoses in patients treated with external beam radiation: pathophysiological basis and endovascular treatment

External beam radiation-induced stenoses isolated to the coronary arteries or peripheral vessels have been previously described. We report for the first time the clinical presentation of two patients with concomitant coronary artery and multiple arch vessel disease following external beam radiation of the chest. We review the pathophysiology, discuss the treatment options and describe the percutaneous treatment of coronary, carotid, subclavian, and axillary stenoses related to this rare but likely underdiagnosed disorder.

Carotid artery surgery vs. stent: A cardiovascular perspective

Stroke is a major health catastrophe that is responsible for the third most common cause of death and the leading cause of disability. Carotid artery stenosis is an important cause of brain infarctions and the risk of stroke is directly related to the severity of carotid artery stenosis and to the presence of symptoms. Familiarity with different methods of measuring degrees of carotid artery stenosis is a key in understanding the role of revascularization of this disorder. Carotid endarterectomy (CEA), surgical removal of the carotid atherosclerotic plaque, is intended to prevent stroke in patients with carotid artery stenosis and currently the most commonly performed vascular procedure in the United States. Several randomized clinical trials had demonstrated the benefits of CEA in selected groups of patients with symptomatic and asymptomatic carotid artery stenosis. However, CEA can cause stroke, the very thing it intended to prevent, and is associated with significant perioperative complications such as those related to general anesthesia, cardiac or nerve injury. Moreover, several anatomical and medical conditions may limit candidates for CEA. Carotid artery stenting (CS) is an evolving and less invasive technique for carotid artery revascularization. Recent studies demonstrated that CS with embolic protection devices has become an alternative to CEA for high-surgical-risk patients and the procedure of choice for stenoses inaccessible by surgery. The role of CS in low risk patients awaits the completion of several ongoing studies.

Extracranial revascularization therapy: Angioplasty and stenting

Beginning with simple balloon angioplasty, minimally invasive revascularization techniques have progressed to the use of metallic stents for improved immediate and long-term results. Stent-supported angioplasty now offers a therapeutic option for those individuals ineligible for surgical revascularization of stenotic atherosclerotic lesions and who have failed maximal medical therapy. However, the clinical equivalence, or possibly even superiority, of angioplasty of the extracranial carotid and vertebral arteries in atheromatous occlusive disease over surgical revascularization has yet to be determined in ongoing randomized controlled trials. Additionally, endovascular techniques offer treatment for a variety of nonatherosclerotic disease affecting the extracranial arteries, such as inflammatory, radiation-induced, and postsurgical strictures; acute intimal dissection; traumatic and spontaneous arteriovenous fistulas; and aneurysms or pseudoaneurysms. For certain disease entities at high risk for surgical complications, endovascular procedures have gained preference as the therapeutic modality of choice, yet lacking controlled trials providing evidence for noninferiority against surgical approach. Continued innovation and refinement of endovascular technology and techniques will further improve technical success, reduce procedure-related morbidity, and broaden the endovascular therapeutic spectrum for extracranial and intracranial cerebrovascular disease.

Focused high-risk population screening for carotid arterial stenosis after radiation therapy for head and neck cancer††This is an original work by the above authors. The opinions expressed are the authors' and the authors' alone. They do not necessarily reflect the opinion of the United States government, the Department of Defense, or Madigan Army Medical Center

BACKGROUND

Cervical radiation for head and neck cancer has been associated with an increased incidence of carotid arterial stenosis. Modern radiation therapy delivers higher doses with increasing long-term survival. Accordingly, the prevalence of radiation-associated carotid stenosis may be higher than previously reported. Phase I of this prospective study was to establish the prevalence of carotid artery stenosis after high-dose cervical radiation.

METHODS

From a prospectively maintained database, we identified patients who had received cervical high-dose radiotherapy (minimum 5,500 cGy). All patients were screened with bilateral carotid arterial duplex ultrasonography. We defined disease as "normal or mild" if the carotid stenosis was <50%, and "significant" if >50%. The relationship between standard demographic risk factors and screening outcomes was then analyzed.

RESULTS

Screening was performed in 40 patients (mean age 68.2 years, range 26 to 87). Patients received a mean cumulative radiation dose of 6,420 cGy (range 5,500 to 7,680), with a mean duration of 10.2 years since their last radiation treatment. Sixteen patients (40%) had significant carotid artery stenosis. Patients with and without significant stenosis were comparable in terms of age, radiation dose, tobacco use, comorbidities, and postradiation interval (P = not significant). Six patients (15%) had unilateral complete carotid occlusion and 6 patients (15%) had significant bilateral carotid stenosis. Three patients (7.5%) had sustained a previous stroke after radiation therapy.

CONCLUSIONS

The prevalence of carotid arterial disease in patients with prior cervical radiation therapy is clinically significant and warrants aggressive screening as part of routine preradiation and postradiation care. Focused screening of this high-risk population may be cost effective and medically beneficial in terms of risk factor modification and stroke prevention, and will be examined in phase II of this study.

Accelerated progression of carotid stenosis in patients with previous external neck irradiation

OBJECTIVE

Radiotherapy to the head and neck often results in carotid stenosis, but the course of disease is unknown. We investigated the natural history and progression of asymptomatic carotid stenosis induced by external irradiation. Patients and methods The study included 130 carotid arteries in 95 patients who had received external radiation therapy to the head and neck area and who had asymptomatic, mild internal carotid artery or common carotid artery stenosis. Stenosis of 15% to 49% on duplex ultrasound (US) scans defined mild (<50%) disease. Another 95 arteries in 74 patients with matched degree of carotid artery stenosis but who had not received radiation therapy were used as control. Both groups were followed up prospectively with serial duplex US scanning, and degree of carotid artery stenosis was categorized as 15% to 49%, 50% to 69%, 70% to 99%, and occlusion. Progression of carotid artery stenosis was defined as increase in stenosis from less than 50% to 50% or greater at ultrasonography. Secondary end points included progression to higher disease category, new cerebrovascular symptoms, and death. Data from irradiated arteries was compared with control data with the life table method. A Cox regression model was used to analyze disease progression, adjusted for covariates of sex, age, smoking, diabetes, and hypertension.

RESULTS

Mean follow-up was 36 months. Adjusted freedom from progression rates at 3 years were 65% for irradiated arteries and 87% for control arteries at life-table analysis (P =.035; odds ratio, 3.1). The annualized progression rate from less than 50% to 50% or greater in irradiated arteries was 15.4%, compared with 4.8% in nonirradiated arteries. A long history of cervical irradiation (>6 years) was the only significant risk factor for disease progression. There was no difference between the two groups regarding development of new symptoms or mortality.

CONCLUSIONS

Carotid stenosis associated with external irradiation progresses more rapidly compared with nonirradiated atherosclerotic arteries. Aggressive surveillance is recommended.

Carotid artery revascularization through a radiated field

OBJECTIVE

Extracranial carotid stenosis is a complication of external head and neck irradiation. The safety and durability of carotid artery revascularization through a radiated field has been debated. We describe the immediate and long-term results in a series of 27 consecutive patients who received treatment over 12 years.

METHODS

From May 1990 to May 2002, 27 consecutive patients underwent 30 primary carotid artery revascularization procedures. All patients had received previous radiation therapy within a mean interval of 10 years (range, 1-26 years), with average radiation dose of 62 Gy (range, 50-70 Gy). Moderate to severe scarring of the skin or radiation fibrosis was present in three fourths of patients. Thirteen patients (48%) had undergone radical neck dissection, and 2 patients had a permanent tracheotomy. The indications for carotid surgery included high-grade (>70%) symptomatic stenosis in 18 patients (60%) and high-grade asymptomatic stenosis in 12 patients (40%). General anesthesia with systematic shunting was used in 18 patients (60%), and regional anesthesia with selective shunting was used in 12 patients (40%). Operations included standard carotid endarterectomy (n = 20), with patch angioplasty (n = 12) or direct closure (n = 8); carotid interposition bypass grafting (n = 7); and subclavian to carotid bypass grafting (n = 3). Primary closure of the surgical wound was performed in all procedures without any special muscular or skin flaps. All patients were followed up for a mean of 40 months (range, 3-99 months).

RESULTS

There was one (3.3%) perioperative death, from massive intracerebral hemorrhage; and 1 patient had a transient ischemic attack. In-hospital complications included neck hematoma in 2 patients, which required surgical drainage in 1 patient. There was neither delayed wound healing nor infection. Twelve patients died during follow-up, of causes not related to treatment. None of the surviving patients had further stroke, and all remained asymptomatic. Follow-up duplex scans showed asymptomatic recurrent stenosis greater than 60% in 3 patients, 2 of whom with stenosis greater than 80% underwent repeat operation. Risk for recurrent stenosis greater than 60% at 18 months was 16.6%. Recurrent stenosis occurred in 2 of these patients after saphenous vein bypass, and in 1 patient after endarterectomy with vein patch angioplasty.

CONCLUSION

The clinical results and sustained freedom from symptoms and stroke over 40-month follow-up suggests that carotid revascularization through a radiated field is a safe and durable procedure in patients at high surgical risk, despite a marked incidence of recurrent stenosis.

Early outcome of carotid angioplasty and stenting with and without cerebral protection devices: a systematic review of the literature

BACKGROUND

Carotid angioplasty and stenting (CAS) is increasingly being used for treatment of symptomatic and asymptomatic carotid artery disease (CAD). To evaluate the efficacy of cerebral protection devices in preventing thromboembolic complications during CAS, we conducted a systematic review of studies reporting on the incidence of minor stroke, major stroke, or death within 30 days after CAS.

SUMMARY OF REVIEW

We searched for studies published between January 1990 and June 2002 by means of a PubMed search and a cumulative review of reference lists of all relevant publications. In 2357 patients a total of 2537 CAS procedures had been performed without protection devices, and in 839 patients 896 CAS procedures had been performed with protection devices. Both groups were similar with respect to age, sex distribution, cerebrovascular risk factors, and indications for CAS. In many studies the periprocedural complication rates had not been presented separately for patients with symptomatic and asymptomatic CAD. The combined stroke and death rate within 30 days in both symptomatic and asymptomatic patients was 1.8% in patients treated with cerebral protection devices compared with 5.5% in patients treated without cerebral protection devices (chi2=19.7, P<0.001). This effect was mainly due to a decrease in the occurrence of minor strokes (3.7% without cerebral protection versus 0.5% with cerebral protection; chi2=22.4, P<0.001) and major strokes (1.1% without cerebral protection versus 0.3% with cerebral protection; chi2=4.3, P<0.05), whereas death rates were almost identical (approximately 0.8%; chi2=0.3, P=0.6).

CONCLUSIONS

On the basis of this early analysis of single-center studies, the use of cerebral protection devices appears to reduce thromboembolic complications during CAS. These technical aspects should be taken into account before the initiation of further randomized trials comparing CAS with carotid endarterectomy.

Efficacy of a nitinol filter device in the prevention of embolic events during carotid interventions

PURPOSE

To evaluate the feasibility, safety, and efficacy of the TRAP Vascular Filtration System (VFS) during carotid interventions as a deterrent to embolic complications.

METHODS

Thirty-one consecutive patients (18 men; mean age 72 +/- 8 years) gave informed consent to undergo elective percutaneous angioplasty and stenting of the extracranial carotid artery protected by the TRAP VFS, a nitinol basket filter system.

RESULTS

The TRAP VFS was delivered and retrieved safely in all patients; procedural success for carotid stenting was 100%. In 3 (9.7%) cases, the filters were positioned after lesion predilation. Nearly half (13, 41.9%) of the retrieved filters contained visible plaque debris that histology identified as cholesterol crystals, fibrin material, atheromatous plaque, and macrophage foam cells. There were no symptomatic major or minor neurological complications encountered in this cohort during hospitalization.

CONCLUSIONS

Our data indicate that percutaneous dilation and stenting of the carotid artery protected by TRAP VFS appears to be feasible, safe, and effective in preventing cerebral embolization.

Carotid artery stenting for stenosis following revascularization or cervical irradiation

PURPOSE

To assess the safety and efficacy of carotid artery stenting (CAS) for stenosis following revascularization or cervical irradiation.

METHODS

Twenty-two CAS procedures performed on 21 patients (20 men; mean age 69.3 years, range 58-87) from June 1997 to June 2000 were retrospectively reviewed. There were 5 radiation-induced carotid stenoses in 4 patients and 17 postsurgical restenoses. The mean interval between carotid revascularization and CAS was 48.1 months (range 6-264), while the elapsed time from irradiation to CAS was always >8 years (range 8-28). Seven patients screened during this period were excluded from CAS because of a duplex-defined >50% hypoechoic lesion and/or angiographic documentation of an irregular ulcerated stenosis.

RESULTS

Four Palmaz and 16 Wallstents were successfully deployed in 20 arteries; 1 access failure prompted conversion to surgery and a stent delivery failure resulted in 1 patient receiving balloon dilation only (technical success 91%). No complications were encountered in the periprocedural period, and no neurological events were observed during a mean follow-up of 16.6 months (range 3-36). One patient died at 20 months from an unrelated cause. One (4.8%) restenosis was detected after 1 year in the patient who did not receive a stent.

CONCLUSIONS

CAS is a safe alternative to conventional surgery in patients with carotid artery stenosis following surgical revascularization or cervical irradiation provided preoperative testing excludes stenoses at risk for embolism.

Catheter modification for easier cannulation of the carotid artery during angioplasty and stenting

PURPOSE

To present a modification of both the guiding catheter and stent delivery system to facilitate access into sharply curved supra-aortic vessels during carotid angioplasty.

TECHNIQUE

Access failures during carotid interventions typically occur because either the vessel origin is acutely angled or the stenosis is located proximal to the carotid bifurcation, limiting access to the external carotid artery. We directly catheterized the left common carotid artery or brachiocephalic trunk with a guiding catheter whose tip had been curved by steam-shaping. The tip of the stent delivery system also was molded into a curve by this process so it engaged the curved part of the guiding catheter without pulling it out of the vessel.

CONCLUSIONS

This simple modification can improve the success rate of carotid cannulation via the femoral approach and does not seem to increase the risk of the intervention.

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.

Treating complex nervous system vascular disorders through a "needle stick": origins, evolution, and future of neuroendovascular therapy

In the past few decades, dramatic improvements have occurred in the field of neuroendovascular surgery. Endovascular therapy today is a well-established treatment modality for a variety of cerebrovascular and nonvascular central nervous system diseases. The foundation of this spectacular evolution was laid by the efforts of pioneering visionaries who often worked alone and under difficult, almost impossible, conditions. Ongoing device development and refinement have revolutionized the field at a dizzying, exhilarating pace. With a better understanding of the molecular basis of diseases and further advancements in gene therapy, neuroendovascular techniques have an enormous potential for application to the entire spectrum of central nervous system diseases as a minimally invasive vehicle for the delivery of biological factors.

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 stenting for radiation-induced stenoses: A report of 7 cases

BACKGROUND AND PURPOSE

Radiation-induced stenoses of the carotid artery are associated with fibrosis of the arterial layers and tissue planes that renders their surgical treatment difficult. We present our clinical experience in carotid angioplasty stenting (CAS) of patients harboring such stenoses.

METHODS

Seven patients underwent transfemoral CAS of 10 radiation-induced stenoses located on either the common or the internal carotid artery. Six patients presented neurological symptoms. Four patients had undergone previous radical neck dissection, and 3 had permanent tracheostomies. Stenoses were primarily covered with a self-expandable stent before carotid dilation.

RESULTS

All interventions were successful, with residual stenoses <20%. No permanent complication occurred. The mean follow-up was 8 months. Patients were symptom free at the last clinical examination, and Doppler control showed no evidence of restenosis.

CONCLUSIONS

Carotid stenting appears very attractive for such "hostile neck" patients and seems a safe and efficient treatment for radiation-induced stenoses.