Stent deformation and intimal hyperplasia complicating treatment of a post-carotid endarterectomy intimal flap with a Palmaz stent

Management of postoperative internal carotid artery intimal flap after carotid endarterectomy: a cohort study and systematic review

OBJECTIVE

Postoperative internal carotid artery (ICA) intimal flap (IF) is a potential complication after carotid endarterectomy (CEA) for carotid artery stenosis. There are no clear recommendations in the current literature on the management of this condition due to sparse evidence. Some authors advocate carotid stent placement or reoperation, while others suggest watchful waiting. The aim of this study was to analyze incidence and management strategies of postoperative ICA-IF, and moreover, to put these findings into context with a systematic literature review.

METHODS

The authors retrospectively reviewed all consecutive CEA cases performed at the University Hospital of Bern over a decade (January 2008 to December 2018). The incidence of postoperative ICA-IF, risk factors, management strategies, and outcomes were analyzed. These results were put into context with a systematic review following the PRISMA guidelines.

RESULTS

A total of 725 CEAs were performed between January 2008 and December 2018. Postoperative ICA-IF was detected by routine duplex neurovascular ultrasound (NVUS) in 13 patients, corresponding to an incidence rate of 1.8% (95% CI 1.0%-3.1%). There were no associated intraluminal thrombi on the detected IF. Intraoperative shunt placement was used in 5.6% and one or more intima tack sutures were performed in 42.5% of the 725 cases. There was no significant association between intraoperative shunt placement and the occurrence of an IF (p > 0.99). Two patients (15.4%) with IF experienced a transient postoperative neurological deficit (transient ischemic attack). In these cases, the symptoms resolved spontaneously without any interventions or change in the antiplatelet regimen. All other cases (84.6%) with IF were asymptomatic. In 1 patient (7.7%) with IF, the antiplatelet treatment was switched from a mono- to a dual-antiaggregating regimen because the IF led to a stenosis > 70%; this patient remained asymptomatic. All cases of IFs were managed conservatively with close radiological follow-up evaluations, without reoperation or stenting of the ICA. All 13 IFs vanished spontaneously after a mean duration of 6.9 months (median 1.5 months, range 0.5-48 months). A systematic literature review revealed a postoperative ICA-IF incidence of 3.0% (95% CI 2.1%-4.1%) with relatively heterogenous management strategies.

CONCLUSIONS

Postoperative ICA-IF is a rare finding after CEA. Conservative therapy with close NVUS follow-up evaluations appears to be an acceptable and safe management strategy for asymptomatic IFs without associated intraluminal thrombi.

Delayed Stroke after Aneurysm Treatment with Flow Diverters in Small Cerebral Vessels: A Potentially Critical Complication Caused by Subacute Vasospasm

Flow diversion (FD) is a novel endovascular technique based on the profound alteration of cerebrovascular hemodynamics, which emerged as a promising minimally invasive therapy for intracranial aneurysms. However, delayed post-procedural stroke remains an unexplained concern. A consistent follow-up-regimen has not yet been defined, but is required urgently to clarify the underlying cause of delayed ischemia. In the last two years, 223 patients were treated with six different FD devices in our center. We identified subacute, FD-induced segmental vasospasm (SV) in 36 patients as a yet unknown, delayed-type reaction potentially compromising brain perfusion to a critical level. Furthermore, 86% of all patients revealed significant SV approximately four weeks after treatment. In addition, 56% had SV with 25% stenosis, and 80% had additional neointimal hyperplasia. Only 13% exhibited SV-related high-grade stenosis. One of those suffered stroke due to prolonged SV, requiring neurocritical care and repeated intra-arterial (i.a.) biochemical angioplasty for seven days to prevent territorial infarction. Five patients suffered newly manifested, transient hemicrania accompanying a compensatorily increased ipsilateral leptomeningeal perfusion. One treated vessel obliterated permanently. Hence, FD-induced SV is a frequent vascular reaction after FD treatment, potentially causing symptomatic ischemia or even stroke, approximately one month post procedure. A specifically early follow-up-strategy must be applied to identify patients at risk for ischemia, requiring intensified monitoring and potentially anti-vasospastic treatment.

Carotid Endarterectomy to Remove Retained Solitaire Stent Retriever inside Carotid Stent after Mechanical Thrombectomy

BACKGROUND

Tandem occlusions of the internal carotid artery (ICA) and middle cerebral artery (MCA) occur in up to a third of patients with acute ischemic strokes undergoing endovascular mechanical thrombectomy. Understanding open neurosurgical management of associated complications with this procedure is important.

CASE REPORT

A 67-year-old man with acute onset of left hemiparesis and a tandem right ICA and MCA occlusion. He underwent carotid stent angioplasty of a stenotic ICA, followed by attempted Solitaire stent retrieval of an MCA clot. On withdrawal, the tines of the Solitaire stent lodged inside the Precise carotid stent. The patient was started on aspirin, Plavix, and heparin infusion, and underwent a carotid endarterectomy (CEA) with safe removal of the stents and primary vessel repair.

CONCLUSION

This is the first case reported to date of a Solitaire stent becoming lodged inside a Precise carotid stent, salvaged by CEA with safe removal of the stents and primary vessel repair. We discuss the timing, indication, alternatives, and technical nuances of a CEA in this setting.

Reoperation for Recurrent Carotid Stenosis: A Ten-Year Experience

Owing to the supposed risks of reoperation, carotid stenting has been proposed as a treatment for carotid restenosis. The purpose of this study is to determine the safety and efficacy of carotid reoperation. From March 1988 to March 1997, 40 patients, 18 men and 22 women (mean age: 65 years) underwent a total of 43 redo carotid procedures by our group. Two patients had both sides repaired and one required a second reoperation. Symptomatic recurrent carotid stenosis (>70%) was the indication in 25 reoperations and asymptomatic high-grade stenosis (>80%) was the indication in 18. The initial operation in 35 reoperations was carotid endarterectomy (CEA) with primary closure and in eight it was CEA with a prosthetic patch. The interval to recurrence was less in the 24 reoperations in patients who had myointimal hyperplasia (21 months) compared with 17 reoperations in patients with recurrent atherosclerosis (90 months). The other two reoperations were for an intimal flap 2 months after the original CEA, and for operative dilation of fibromuscular dysplastic bands missed on magnetic resonance angiography (MRA), distal to the site of a previous CEA.

The technique of reoperation included redo CEA in two, CEA with vein patch in eight, CEA with prosthetic patch in 22, vein interposition graft in five, and prosthetic interposition graft in five. In addition, operative dilation with an arterial dilator was used in one reoperation.

No perioperative strokes or deaths occurred other than one patient who died from cardiac complications following combined CEA and coronary artery bypass grafting. Operative morbidity consisted of pneumonia in one patient, reversible cranial nerve injury in four, and hematoma requiring evacuation in two. During follow-up (mean: 34 months), carotid occlusion resulted in a mild stroke in one patient, there were 10 late deaths not related to carotid disease, one patient required a reoperation, and three patients were lost to follow-up.

The authors conclude that reoperation for recurrent carotid stenosis, using standard vascular techniques, is both safe and effective; it should continue to be the mainstay of treatment when intervention is required.

Angioplasty and Stenting of the Extracranial Carotid Arteries

Purpose:

To study the feasibility and safety of stent-supported angioplasty in the treatment of atherosclerotic stenoses of the extracranial carotid arteries.

Methods:

Carotid angioplasty was attempted in 174 arteries (163 patients: 126 males; mean age: 71 ± 10 years, range 47 to 93). Mean lesion length was 15.1 ± 4.1 mm, and mean percent stenosis was 83.8% ± 7.3% (reference diameter 5.8 ± 0.7 mm). The majority (106, 65%) were asymptomatic (51% of all patients had severe coronary disease, 32% had peripheral vascular diseases). Patients underwent independent neurological examination, computed tomography, duplex ultrasonography, and angiography preprocedurally, 24 hours after the procedure, and at 6-month follow-up intervals. Most (142, 82%) carotid arteries were treated without cerebral protection, but a protective triple coaxial catheter was used in 32 (18%) patients. Stents (primarily Palmaz and Wallstent) were deployed routinely in all cases; 18% were implanted without predilation.

Results:

Immediate technical success was 173 of 174 (99.4%) (1 access failure referred electively to surgery). Eight (4.6%) neurological complications occurred in the periprocedural period: 3 transient ischemic attacks, 2 minor strokes, and 3 major strokes (1 amaurosis and 2 hemiplegias). Two major complications developed despite cerebral protection. There were no deaths or myocardial infarctions and only 3 cervical access site hematomas. Over a mean 12.7 ± 9.2 month follow-up (range 1 to 36), no ipsilateral neurological complications have been seen. There were 4 (2.3%) restenoses (3 redilated, 1 treated medically) and 1 mild Palmaz stent compression, all found within the first 6 months. Primary and secondary patencies at 3 years are 96% and 99%, respectively.

Conclusions:

Angioplasty with routine stenting seems feasible and safe for treating certain types of carotid stenoses even in high-surgical risk patients; however, randomized trials are necessary before this treatment can be offered as an alternative to endarterectomy.

Endovascular Stents for Carotid Artery Occlusive Disease

Purpose:

To study the feasibility and safety of endovascular stenting of cervical carotid artery stenosis.

Methods:

Between April 1994 and May 1997, 108 consecutive patients (58 men; mean age 70.1 years) with ≥ 70% carotid stenosis were treated with percutaneous stent implantation under a protocol that featured independent neurological review. Forty-four percent were asymptomatic. Over half the lesions (59%) were in the internal carotid artery; the mean stenosis was 86%. Palmaz stents were implanted without cerebral protection following preliminary balloon dilation; two Wallstents were used in long lesions.

Results:

Carotid stents were successfully placed in 108 of 114 (95%) lesions. Of the 6 technical failures, 5 were access related and 1 was due to seizures during balloon dilation. Two major (1.8%) and 2 minor (1.8%) strokes occurred (3.7% stroke rate for 108 patients; 3.5% in 114 procedures), all in symptomatic patients, one of whom died. There were 5 (4.4%) transient ischemic attacks and 2 (1.8%) brief seizure episodes during dilation. One patient died of a cardiac event on day 20. The all stroke or death rate was 5.3% based on 114 arteries at risk (5.6% in 108 patients). In the mean 6-month follow-up (range 1 to 36) of 97 eligible patients, 3 (3.1%) died from unrelated causes. There was 1 restenosis (1.0%) from a stent compression, which was successfully redilated. There were no neurological sequelae, cranial palsies, or cases of stent or vessel thrombosis in follow-up.

Conclusions:

The use of stents in the treatment of cervical carotid occlusive disease appears feasible, effective in the short term, and without excessive risk of periprocedural stroke.

Traumatic Subclavian Artery Pseudoaneurysm: Periprocedural Salvage of Failed Stent-Graft Exclusion Using Coil Embolization

Purpose:

To report the exclusion of a subclavian pseudoaneurysm by a combination of covered stent implantation and coil embolization.

Case Report:

A 30-year-old man presented with a posttraumatic pseudoaneurysm of the left subclavian artery. A covered Jostent was inserted via a percutaneous femoral approach and deployed in the injured subclavian artery. Because of tapering of the artery proximally, apposition of the covered stent to the arterial wall was insufficient, leading to persistent filling of the pseudoaneurysm. Exclusion of the pseudoaneurysm was achieved by coil embolization through a gap between the stent-graft and the arterial wall.

Conclusions:

This report illustrates that successful endovascular treatment of a left subclavian pseudoaneurysm may require a combination of catheter-based techniques.

Deformation of Self-Expanding Stent-Grafts Complicating Endovascular Peripheral Aneurysm Repair

Purpose:

To demonstrate the deformation of self-expandable stents after endovascular repair of peripheral aneurysms.

Methods and Results:

The Corvita Endoluminal Graft was used to treat a traumatic false aneurysm of the right subclavian artery and a common iliac artery aneurysm in 2 patients. In the subclavian case, the stent-graft showed a “cigar-shaped” deformation with hemodynamically significant stenoses at the proximal and distal ends at 3 months. In the second case, the same type of deformity was noted only 1 day after implantation. Two months later, the stent-graft occluded, necessitating surgical repair.

Conclusions:

Both cases demonstrate the possibility of stent deformation of self-expanding stent-grafts implanted at arterial sites not subject to external compression.

Histopathologic evaluation of a novel‐design nitinol stent: the Biflex stent

BACKGROUND

Optimalization and improvement in stent material, stent design and deployment may alleviate the problem of restenosis after stenting. The Biflex stent is a novel-design stent made of nitinol; the vascular response after deployment in rabbit iliac arteries was evaluated.

METHODS AND RESULTS

Normocholesterolemic New Zealand white rabbits (n = 8) were used. Iliac arteries were randomized to receive either a stainless steel control stent or a nitinol stent and rabbits were euthanized at 30 days after implantation. All animals survived and there were no adverse events. Vessels were harvested and prepared for histopathologic analysis and histomorphometry. Stents were well opposed to the vessel wall and thrombi were absent. The lumen area and the area within the internal elastic lamina were significantly larger in the nitinol stent group as opposed to the control group (3.8 +/- 0.1 vs 3.3 +/- 0.1 mm, p = 0.009 and 4.6 +/- 0.1 vs 4.1 +/- 0.2 mm, p = 0.03, respectively). There were no differences in injury score, neointimal area, medial area, area within the external elastic lamina and amount of inflammatory cells. Staining for alpha-smooth muscle cell actin and endothelium did not show any differences between the two groups as assessed semiquantitatively.

CONCLUSION

This nitinol stent with a novel design demonstrated acceptable biocompatibility in iliac arteries of normocholesterolemic rabbits with minimal foreign-body reaction and minimal neointimal formation.

Refractory In-stent Restenosis Following Carotid Artery Stenting: A Case Report and Review of Operative Management

In-stent restenosis following carotid artery stenting is a challenging problem that vascular surgeons will likely encounter with increasing frequency. The following describes a patient who developed progressive in-stent restenosis 3 years after carotid artery stenting, which was treated with operative therapy after failed balloon angioplasty. A review of the literature describing surgical approaches to the treatment of in-stent restenosis was also performed.

Carotid Stent Failure: Results of Surgical Rescue

AIM

Little data is available on surgical "rescue" of failed carotid stents (CAS). We have analyzed a series of CAS failures treated by conventional open surgery.

REPORT

Five patients underwent surgery after CAS failure, either electively (4) or as an emergency (1). Elective surgical "rescue" was for stent restenosis (2 cases) or stent misplacement (2 cases). Emergency surgery was performed for entrapment of the protection system in the stent. Surgical rescue was accomplished by perimedial endarterectomy and "en bloc" plaque and stent extraction in 3 cases, and by vein bypass in 2 cases, with no neurological complications.

CONCLUSION

Surgical rescue of failed CAS is effective.

Delayed deformation of self-expanding stents after carotid artery stenting for postendarterectomy restenoses

Carotid artery stenting has become an acceptable alternative for treating patients with severe atherosclerotic lesions, particularly those with significant surgical risks, such as recurrent stenosis after endarterectomy. Stent deformation, a phenomenon primarily associated with balloon-expandable stents, is largely avoided by exclusively using self-expanding stents in treating carotid artery stenosis. Nonetheless, we herein report two patients who presented with delayed Wallstent deformation after carotid artery stenting for postendarterectomy restenosis. Our cases highlight the need for caution because delayed deformation of self-expanding stents can occur, particularly during treatment of patients with postendarterectomy stenosis. Furthermore, poststent surveillance is imperative in identifying patients with severe restenosis after carotid artery stenting who need reintervention.

SURGICAL MANAGEMENT OF EXTRACRANIAL INTERNAL CAROTID ANEURYSMS BY CERVICAL APPROACH

BACKGROUND

Extracranial internal carotid artery aneurysms (EICAA) are rare vascular problems with a great potential for lethal thromboembolic episodes.

METHODS

From 1994 to 2004, nine patients with EICAA, seven men and two women, were surgically treated for 10 aneurysms in our department. Aneurysm led to hemispheric symptoms in six cases (two hemispheric strokes and four hemispheric transient ischaemic attacks). The cause was fibrodysplasia in two cases, atherosclerosis in four cases, trauma in two cases and spontaneous dissection in two cases. All aneurysms were treated surgically by the cervical approach using shunting. Extended cervical approach was necessary in four patients with high-lying aneurysms. Nine aneurysms were totally resected and successful revascularization was carried out. Open aneurysmorrhaphy with vein patch angioplasty was carried out in one case of a saccular aneurysm.

RESULTS

There were no perioperative deaths or transient ischaemic attacks or strokes. Four patients developed cranial nerve deficits: one had hoarsness, two had partial facial paralysis (patients with extended cervical approach) and one had tongue deviation. These neurological symptoms were observed in large aneurysms (>4.5 cm) and disappeared within 14 months. No neurological complication was observed in a follow up that ranged from 6 months to 10 years.

CONCLUSIONS

Surgical repair of EICAA, especially with total resection and arterial reconstruction, is strongly recommended. Extended cervical approach has many technical difficulties but can allow treatment of high-lying aneurysms.

A Series of 15 Patients with Extracranial Carotid Artery Aneurysms: Surgical and Endovascular Treatment

OBJECTIVES

This is a retrospective review of 15 patients with primary and secondary aneurysms of extracranial carotid arteries treated surgically and endoluminally over 20 years in one centre.

PATIENTS AND METHODS

Fifteen aneurysms of extracranial carotid arteries were noticed in the same number of patients: five atherosclerotic, two after previous carotid surgery, six post-traumatic, one inflammatory, one of unknown etiology. All of them were symptomatic.

RESULTS

In the group treated surgically some complications occurred in the perioperative time: one haematoma, two transient neurological deficits, one fatal stroke. In the endovascular group of patients no complications occurred after the treatment. One fatal stroke occurred during operation-the patient died on the 43rd postoperative day due to respiratory insufficiency. Two other deaths occurred during the follow-up: one caused by myocardial infarction 10 years after the aneurysm resection, and the second due to a fatal stroke 3 years after aneurysmorraphy. One patient refused treatment and died 9 months after being diagnosed.

CONCLUSION

Neurological deficits in patients after neck injuries should arouse the suspicion of the presence of a carotid artery aneurysm. Open repair remains the method of choice in treating carotid artery aneurysms but endovascular procedures create the possibility of treating extracranial aneurysms in selected cases when open surgery is not recommended.

Operative management of carotid artery in-stent restenosis: first experiences and duplex follow-up

OBJECTIVES

Carotid Artery Stenting (CAS) may be comparable to Carotid Endarterectomy (CEA) as a durable and effective procedure in stroke prevention. Concern remains about the incidence of restenosis after stenting and its management. We evaluated the surgical management of restenosis after CAS.

DESIGN

prospective study.

METHODS

between December 1997 and April 2001, 217 CAS procedures were performed in 217 patients (155 men and 62 women; age 70 years +/- 8.2). After a mean of 8 months post-stenting four patients (two symptomatic, two asymptomatic with contralateral occlusion) with severe haemodynamic in-stent restenosis (90-99%) had surgical reintervention.

RESULTS

standard CEA with removal of the stent was performed in all four patients. No major complications occurred. Intima hyperplasia showed to be the predominant mechanism leading to in-stent restenosis. All four surgically treated patients remained asymptomatic and without recurrent restenosis over a mean follow-up time of 13 months (range 3-20 months).

CONCLUSION

the optimal treatment of in-stent restenosis has yet to be defined, but standard CEA with removement of the stent appears to be feasible.

Surgical management of acute complications and critical restenosis following carotid artery stenting

Carotid artery angioplasty with stenting (CAS) is being increasingly used in the treatment of extracranial carotid artery stenosis. As in other catheter-based approaches to the treatment of arterial disease, surgical intervention may be required because of either acute complications or correct critical restenosis. We have reviewed our experience managing early complications and critical in-stent restenoses after CAS in a tertiary care university hospital and a Veterans Affairs Medical Center. During the last 5 years, 22 carotid arteries (21 patients) underwent CAS. One patient developed thrombosis and rupture of the carotid artery during stenting. Two other patients (3 arteries) developed critical restenosis within 12 months. Subsequent surgical reconstructions included an internal carotid artery (ICA)-to-external carotid artery (ECA) transposition and a common carotid artery (CCA)-to-ICA bypass with reversed saphenous vein (RSV). The patient who underwent CCA-to-ICA bypass later required subclavian-to-ICA bypass because of rapidly progressive intimal hyperplasia and subsequent occlusion of the CCA. The other patient has not had surgical repair because of his deteriorating condition and significant co-morbidities. During the same time period, two additional patients were referred from outside institutions specifically for surgical intervention after carotid stenting. One had delayed rupture of the carotid artery 1 day after stenting and underwent urgent surgical repair. Another patient had early, critical restenosis within the stent and underwent placement of a CCA-to-ICA interposition graft using RSV. Acute treatment failures after CAS can be successfully managed using standard surgical techniques. Patients who develop critical in-stent restenosis requiring surgical repair may need more challenging surgical reconstructions to maintain cerebral perfusion.

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.

Internal to external carotid artery transposition to repair recurrent stenosis after carotid artery stenting

Recently, carotid artery stenting (CAS) has emerged as a treatment option for carotid artery stenosis. Since the procedure is new, management of its complications is not standardized. This case report describes one method of arterial reconstruction after failed CAS. A 64-year-old male underwent CAS of his right internal carotid artery (ICA) for an asymptomatic 65% stenosis. Seven months later the stented area had narrowed to 95%. Arteriography revealed that the common and external carotid arteries (ECA) were free of disease so we elected to perform a transposition of the distal ICA onto the proximal ECA. The ECA and its branches were completely mobilized and the ascending pharyngeal and lingual arteries divided. The ICA was divided distal to the stent. Transection of the occipital artery provided an arteriotomy for an end ICA to side ECA anastamosis, thus preserving ECA flow. Postoperative surveillance after 8 months has revealed no recurrent stenosis. Operative repair of restenosis after CAS may be challenging if standard endarterectomy is not possible. Other options for reconstruction are feasible but if the common and external carotid arteries are disease-free, an ICA to ECA transposition provides a simple all-arterial repair that avoids bypass and prosthetic material.

The use of stents in the management of neurovascular disease: a review of historical and present status

In the mid-1960s, radiologists began experimenting with stents for use in the peripheral vasculature in the hope of treating vascular insufficiency resulting from vessel stenosis in a nonsurgical manner. The 1990s saw stents move into the neurovascular arena for the management of a variety of disease processes, including arterial and venous sinus stenosis, arterial dissection, arterial aneurysms, and arteriovenous fistulae. This article reviews the current status of stenting in regard to the management of neurovascular maladies.

Short- and long-term histopathologic evaluation of stenting using a self-expanding nitinol stent in pig carotid and iliac arteries

Stenting is increasingly being used to treat carotid artery disease. However, complications including distal embolization, stent thrombosis, stent collapse from external compression, the need for high-pressure inflation with increased neointimal response, or balloon rupture during stent expansion and stent loss are all potential problems and of concern. To address each of these specific concerns, a new stent was designed, which is self-expandable, made of nitinol, with temperature-dependent superelastic properties, and with high vessel wall surface coverage. Since this device has a number of novel characteristics, we aimed to assess the short- and long-term histopathologic response in pig carotid and iliac arteries. Single stents were deployed in pig carotid and iliac arteries after overstretch balloon injury. Angiograms were performed pre- and poststenting and prior to sacrifice. Intravascular ultrasound was used before implantation to determine vessel size. Vessels were examined histologically at 1 month (n = 6) and 6 months (n = 6) for morphometric analysis, hemorrhage and thrombus, endothelialization, and inflammatory and fibrotic responses. There was a 100% angiographic success rate at implantation. In one case, it was determined histologically that a single stent was implanted in a dissection plane of a pig's left iliac artery and was occluded by organized thrombus, with the true lumen being patent. At 6-month follow-up, this was the only evidence of a single stent occlusion, with flow adjacent to the stent in the true lumen. In the other vessels, the stents showed good vessel wall-stent apposition and the lumens were patent with a concentric and thin neointima. Inflammatory cells were rare and there were no mural thrombi. Coverage of the vessel wall by endothelial-like cells was complete at 1 month. The novel nitinol EndoStent appears to have favorable biocompatibility with minimal thrombus deposition or inflammatory response, and its use is feasible for clinical application in carotid and iliac arteries.

Deformation of self-expanding stent-grafts complicating endovascular peripheral aneurysm repair

PURPOSE

To demonstrate the deformation of self-expandable stents after endovascular repair of peripheral aneurysms.

METHODS AND RESULTS

The Corvita Endoluminal Graft was used to treat a traumatic false aneurysm of the right subclavian artery and a common iliac artery aneurysm in 2 patients. In the subclavian case, the stent-graft showed a "cigar-shaped" deformation with hemodynamically significant stenoses at the proximal and distal ends at 3 months. In the second case, the same type of deformity was noted only 1 day after implantation. Two months later, the stent-graft occluded, necessitating surgical repair.

CONCLUSIONS

Both cases demonstrate the possibility of stent deformation of self-expanding stent-grafts implanted at arterial sites not subject to external compression.

Reoperation for carotid stenosis is as safe as primary carotid endarterectomy

PURPOSE

Patients with recurrent carotid artery stenosis are sometimes referred for carotid angioplasty and stenting because of reports that carotid reoperation has a higher complication rate than primary carotid endarterectomy. The purpose of this study was to determine whether a difference exists between outcomes of primary carotid endarterectomy and reoperative carotid surgery.

METHODS

Medical records were reviewed for all carotid operations performed from September 1993 through March 1998 by vascular surgery faculty at a single academic center. The results of primary carotid endarterectomy and operation for recurrent carotid stenosis were compared.

RESULTS

A total of 390 operations were performed on 352 patients. Indications for primary carotid endarterectomy (n = 350) were asymptomatic high-grade stenosis in 42% of the cases, amaurosis fugax and transient ischemic symptoms in 35%, global symptoms in 14%, and previous stroke in 9%. Indications for reoperative carotid surgery (n = 40) were symptomatic recurrent lesions in 50% of the cases and progressive high-grade asymptomatic stenoses in 50%. The results of primary carotid endarterectomy were no postoperative deaths, an overall stroke rate of 1.1% (three postoperative strokes, one preoperative stroke after angiography), and no permanent cranial nerve deficits. The results of operations for recurrent carotid stenosis were no postoperative deaths, no postoperative strokes, and no permanent cranial nerve deficits. In the primary carotid endarterectomy group, the mean hospital length of stay was 2.6 +/- 1. 1 days and the mean hospital cost was $9700. In the reoperative group, the mean length of stay was 2.6 +/- 1.5 days and the mean cost was $13,700. The higher cost of redo surgery is accounted for by a higher preoperative cerebral angiography rate (90%) in redo cases as compared with primary endarterectomy (40%).

CONCLUSION

In this series of 390 carotid operations, the procedure-related stroke/death rate was 0.8%. There were no differences between the stroke-death rates after primary carotid endarterectomy and operation for recurrent carotid stenosis. Operation for recurrent carotid stenosis is as safe and effective as primary carotid endarterectomy and should continue to be standard treatment.

Angioplasty and stenting of the extracranial carotid arteries

PURPOSE

To study the feasibility and safety of stent-supported angioplasty in the treatment of atherosclerotic stenoses of the extracranial carotid arteries.

METHODS

Carotid angioplasty was attempted in 174 arteries (163 patients: 126 males; mean age: 71 +/- 10 years, range 47 to 93). Mean lesion length was 15.1 +/- 4.1 mm, and mean percent stenosis was 83.8% +/- 7.3% (reference diameter 5.8 +/- 0.7 mm). The majority (106, 65%) were asymptomatic (51% of all patients had severe coronary disease, 32% had peripheral vascular diseases). Patients underwent independent neurological examination, computed tomography, duplex ultrasonography, and angiography preprocedurally, 24 hours after the procedure, and at 6-month follow-up intervals. Most (142, 82%) carotid arteries were treated without cerebral protection, but a protective triple coaxial catheter was used in 32 (18%) patients. Stents (primarily Palmaz and Wallstent) were deployed routinely in all cases; 18% were implanted without predilation.

RESULTS

Immediate technical success was 173 of 174 (99.4%) (1 access failure referred electively to surgery). Eight (4.6%) neurological complications occurred in the periprocedural period: 3 transient ischemic attacks, 2 minor strokes, and 3 major strokes (1 amaurosis and 2 hemiplegias). Two major complications developed despite cerebral protection. There were no deaths or myocardial infarctions and only 3 cervical access site hematomas. Over a mean 12.7 +/- 9.2 month follow-up (range 1 to 36), no ipsilateral neurological complications have been seen. There were 4 (2.3%) restenoses (3 redilated, 1 treated medically) and 1 mild Palmaz stent compression, all found within the first 6 months. Primary and secondary patencies at 3 years are 96% and 99%, respectively.

CONCLUSIONS

Angioplasty with routine stenting seems feasible and safe for treating certain types of carotid stenoses even in high-surgical risk patients; however, randomized trials are necessary before this treatment can be offered as an alternative to endarterectomy.

Relationship between oversizing of self-expanding stents and late loss index in carotid stenting

Stenting of the internal carotid artery is facilitated by stenting across the carotid bifurcation and sizing the diameter of a self-expanding stent to the large common carotid segment. This usually results in marked oversizing of the self-expanding stent in the internal carotid segment. This study was done to determine the relationship between stent oversizing and late luminal loss index after stenting of the internal carotid artery. Between September 1995 and March 1997, there were 165 patients (189 vessels) who underwent successful carotid stenting with self-expanding stents. Fifty-nine patients (63 vessels) had six-month follow-up carotid angiograms and on-line quantitative angiographic analysis. The mean reference diameter of the internal carotid arteries was 4.93+/-1.31 mm. Nominal stent size was 5 mm in 4 patients, 6 mm in 6 patients, 8 mm in 106 patients, 10 mm in 77 patients, and 12 mm in 1 patient. The average stent/patient was 1.03+/-0.16. There were three patients who had more than 50% diameter renarrowing at follow-up. The mean late loss index was 0.25+/-0.41. By linear regression analysis, there was no clear linear relationship between stent oversizing and late loss index after stenting (correlation coefficient = -0.21, P = 0.09). When analysis of variance with linear contrast was used to analyze six groups of different stent/artery ratios (from 1.4 to > or = 2), late loss indexes are significantly lower in the groups of high stent/artery ratio than the groups of low stent/artery ratio (P = 0.01). The process of oversizing of self-expanding stents deployed in the internal carotid artery does not appear to be associated with late restenosis and high stent/artery ratio seems to be associated with low late loss index.

Endovascular stents for carotid artery occlusive disease

PURPOSE

To study the feasibility and safety of endovascular stenting of cervical carotid artery stenosis.

METHODS

Between April 1994 and May 1997, 108 consecutive patients (58 men; mean age 70.1 years) with > or = 70% carotid stenosis were treated with percutaneous stent implantation under a protocol that featured independent neurological review. Forty-four percent were asymptomatic. Over half the lesions (59%) were in the internal carotid artery; the mean stenosis was 86%. Palmaz stents were implanted without cerebral protection following preliminary balloon dilation; two Wallstents were used in long lesions.

RESULTS

Carotid stents were successfully placed in 108 of 114 (95%) lesions. Of the 6 technical failures, 5 were access related and 1 was due to seizures during balloon dilation. Two major (1.8%) and 2 minor (1.8%) strokes occurred (3.7% stroke rate for 108 patients; 3.5% in 114 procedures), all in symptomatic patients, one of whom died. There were 5 (4.4%) transient ischemic attacks and 2 (1.8%) brief seizure episodes during dilation. One patient died of a cardiac event on day 20. The all stroke or death rate was 5.3% based on 114 arteries at risk (5.6% in 108 patients). In the mean 6-month follow-up (range 1 to 36) of 97 eligible patients, 3 (3.1%) died from unrelated causes. There was 1 restenosis (1.0%) from a stent compression, which was successfully redilated. There were no neurological sequelae, cranial palsies, or cases of stent or vessel thrombosis in follow-up.

CONCLUSIONS

The use of stents in the treatment of cervical carotid occlusive disease appears feasible, effective in the short term, and without excessive risk of periprocedural stroke.