Technical Strategies for Recurrent Carotid Stenosis following Angioplasty and Stenting
Article Outline
As the number of carotid angioplasty and stent procedures increases, vascular surgeons should anticipate the need for increased surgical correction for complications of stenting and, particularly, in-stent restenosis. This study reviews operative technique alternatives for hemodynamically significant recurrent carotid stenosis following angioplasty and stent placement. Four techniques have been used for repair of carotid in-stent restenosis. All operations were performed with continuous electroencephalographic monitoring. Stents were completely removed in two patients. Operations performed were (1) longitudinal arteriotomy through the stent with patch angioplasty, (2) common carotid to distal internal carotid artery (ICA) bypass with polytetrafluoroethylene (PTFE), (3) subclavian to distal ICA bypass with PTFE, and (4) carotid endarterectomy with complete stent removal and patch angioplasty. Mean operative time was 133 ± 22 min. Mean follow-up was 27.5 ± 29 months. There were no postoperative strokes, myocardial infarctions, or deaths. No cranial nerve injuries were noted. No patients developed postoperative neck hematomas requiring return to the operating room. All patients were stable at follow-up without evidence of recurrent stenosis on postoperative duplex ultrasound. Repair of carotid restenosis following angioplasty and stenting can be achieved with or without complete stent removal. Multiple technical approaches may be required, depending on the length and location of the lesion and stents, the presence of complete common carotid occlusion, and the degree of surrounding inflammation.
Introduction
The incidence of recurrent stenosis after carotid angioplasty and stenting (CAS) for restenosis following carotid endarterectomy (CEA) has been reported to be as high as 75% at 2 years.1 The durability of repeat endovascular interventions for in-stent restenosis has demonstrated mixed results.2, 3, 4 As the number of CAS procedures increases, vascular surgeons need to consider options for operative reconstruction following failure of endovascular management. We have reviewed our experience with all patients who have undergone an open carotid procedure following post-CAS recurrent stenosis or occlusion.
Methods
We report four techniques used to manage carotid in-stent restenosis. Preoperative risk factors were examined (age, gender, presence of documented coronary artery disease, congestive heart failure, prior myocardial infarction, preexisting arrhythmia, hypertension, prior stroke, chronic obstructive pulmonary disease, pulmonary hypertension, smoking history, claudication, and hyperlipidemia). Time from original carotid angioplasty, degree and location of restenosis, and status of the contralateral carotid artery were noted. Presenting neurologic symptoms were also recorded.
Intraoperative variables such as type of reconstruction performed, stent removal, total estimated blood loss, operative time, use of intraoperative electroencephalographic (EEG) monitoring, need for arterial shunting, and type of conduit used were examined. The postoperative course was obtained from the medical record, with documentation of major perioperative (<30 days) complications including stroke, myocardial infarction, arrhythmia, respiratory failure, bleeding, and death. A duplex scan was performed at the first postoperative visit, then at 6 months. If no restenosis was evident, a yearly duplex scan was recommended.
Results
Preoperative duplex untrasound confirmed hemodynamically significant in-stent restenosis of >70% in all patients. Mean age was 58.8 ± 21 years; mean time from stent placement to operation was 43.5 ± 39 months.
One patient presented with transient ischemic attacks, and three patients were asymptomatic at the time of diagnosis. Indications were >90% stenosis in two asymptomatic patients, an occluded common carotid artery (CCA) in an asymptomatic patient with a prior stroke, and a patient with transient ischemic attacks with 70% stenosis and complete occlusion of his contralateral internal carotid artery (ICA). All operations were performed with continuous EEG monitoring. General anesthesia was administered in all cases. No local or regional anesthesia was used. The mean operative time was 133 ± 22 min. Stents were completely removed in two patients. Intraoperative Doppler confirmed normal flow signals in the ICA with characteristic systolic and diastolic components in all patients. Completion angiography was performed in two patients, demonstrating normal flow in the ICA without evidence of persistent stenosis.
The mean postoperative length of stay was 1.5 days. Mean follow-up was 27.5 ± 29 months. There were no postoperative strokes, myocardial infarctions, or deaths. No cranial nerve injuries were noted. No postoperative neck hematomas developed requiring return to the operating room. All patients were stable on follow-up, without evidence of recurrent stenosis on postoperative duplex. Details of all four cases are described below and in Table I.
Table I. Details of the four cases
| Technique | Indication | Operation performed | Age (years) | Location of stenotic lesion | Time to reoperation (months) | Prior secondary endovascular interventions | Stent removed | Follow-up (months) |
|---|---|---|---|---|---|---|---|---|
| 1 | Symptomatic 70% left ICA stenosis, right ICA occlusion | Patch angioplasty | 65 | Carotid bulb | 13 | Balloon angioplasty, stent placement in CCA/ICA | No | 4 |
| 2 | Asymptomatic 90% right ICA in-stent restenosis, failed endovascular treatment | Resection of stent and distal CCA–proximal ICA segment, CCA–ICA bypass with PTFE | 31 | ICA | 15 | Balloon angioplasty | Yes | 60 |
| 3 | Asymptomatic 90% right ICA in-stent restenosis, failed endovascular treatment | Subclavian artery–ICA bypass with PTFE graft | 61 | CCA | 24 | Balloon angioplasty × 2, stent placement in CCA | No | 42 |
| 4 | Asymptomatic 80-99% left ICA in-stent restenosis | Endarterectomy, stent removal, patch angioplasty | 82 | Carotid bulb | 96 | None | Yes | 4 |
Technique 1: Longitudinal Arteriotomy with Stent Wall Removal and Patch Angioplasty
A 65-year-old male suffered a right hemispheric stroke with left-sided hemiparesis; duplex ultrasound demonstrated complete occlusion of his right internal carotid artery and 99% stenosis of his left ICA. He underwent left internal carotid artery angioplasty with placement of two stents. Thirteen months later he was referred to us with transient expressive aphasia and no motor or ocular symptoms. Repeat duplex ultrasound and carotid angiography demonstrated a 70% in-stent restenosis in the left carotid bulb.
Intraoperatively, extensive inflammation was present surrounding the artery containing the stent. A soft portion was noted in the distal ICA. Ischemic changes were noted in continuous EEG upon clamping of the ICA. Longitudinal arteriotomy was performed, and the anterior wall of the stent was divided with Mayo scissors. An arterial shunt was placed between the CCA and the ICA. The luminal surface of the ICA stent was noted to be completely covered with glistening neointima (Fig. 1). Atherosclerotic plaque was pushing the stent inward, producing a short-segment recurrent stenosis. The anterior wall of the artery and stent were resected, and Dacron patch angioplasty was performed. The patient remained asymptomatic postoperatively and was discharged on postoperative day (POD) 2. Follow-up duplex demonstrated normal flow through the carotid bulb and ICA with normal flow velocities. The patient remains neurologically unchanged 4 months postoperatively.
Fig. 1
In case 1, the luminal surface of the ICA stent was completely covered with glistening neointima.
Technique 2: CCA to ICA Bypass
A 31-year-old asymptomatic female underwent CAS of the CCA and bulb after presenting with a right-sided carotid bruit discovered after blunt neck trauma. She underwent repeat angioplasty for an asymptomatic recurrent stenosis found on surveillance duplex several months later, and repeat duplex ultrasound 15 months later confirmed progression of in-stent restenosis. She was referred to UCLA for operative management.
Angiography showed restenosis within the stent. A second area of intimal injury was noted in the distal ICA outside the stent, likely caused by a protection device. Intraoperatively, extensive inflammation was present surrounding the stented artery (Fig. 2). The external carotid artery (ECA) was chronically occluded and was ligated. Both the CCA and ICA were transected. The arterial segment containing the stent was removed and replaced with a 6 mm polytetrafluoroethylene (PTFE) interposition graft (Fig. 3). Intraoperative EEG monitoring demonstrated no changes, and no shunting was required. The patient was discharged home on clopidrogel. Postoperative duplex confirmed normal flow through the PTFE graft 2 years later. She remains asymptomatic at 5 years following her operation.
Fig. 2
In case 2, extensive inflammation was present surrounding the stented artery.
Fig. 3
In case 2, the arterial segment containing the stent was removed and replaced with a 6 mm PTFE interposition graft.
Technique 3: Subclavian Artery to ICA Bypass
A 61-year-old male underwent right CEA with vein patch angioplasty for a >70% symptomatic ICA stenosis. The patient developed recurrent symptoms of left facial numbness 8 months later, and repeat duplex confirmed an 80-99% restenosis distal to the area of the prior endarterectomy; balloon angioplasty was performed at this time. A duplex scan 5 months later demonstrated a 70% recurrent stenosis in the CCA. The patient underwent CAS with a 7 × 60 mm Wallstent. Repeat duplex ultrasound (Boston Scientific, Natick, MA) and angiography 24 months later demonstrated a 90% in-stent restenosis, and he was referred for surgery at UCLA.
Intraoperatively, the distal ICA was found to be soft and free of plaque but pulseless. The CCA was occluded. A right subclavian artery to right ICA bypass was performed with a 6 mm PTFE graft. No EEG changes were noted intraoperatively, and no shunt was required. He had an unremarkable recovery and was discharged home on POD 2. Postoperative duplex at 42 months demonstrated a patent bypass graft with normal flow hemodynamics. The patient remains asymptomatic.
Technique 4: CEA with Patch Angioplasty
An 82-year-old female presented 8 years after bilateral CAS in the right CCA/ICA for asymptomatic stenoses. The patient did not recall stent placement in the left. Duplex ultrasound demonstrated an 80-99% stenosis with soft plaque at the level of the left carotid bulb.
The patient was taken to the operating room for a left CEA. Dense inflammation was noted surrounding the left carotid bifurcation. Arteriotomy revealed a stent, which was not seen on preoperative duplex. The ICA distal to the stent was normal. The stent was not well incorporated in the intima, and the stenosis was primarily atherosclerotic plaque, which had progressed external to the stent and compressed the flow lumen. A clean dissection plane was present in the arterial media. Endarterectomy was performed, and the plaque and stent were removed in their entirety. The chronically occluded ECA was recanalized. Dacron patch angioplasty was performed. The patient was neurologically intact postoperatively and discharged on POD 1. Follow-up duplex ultrasound demonstrated normal flow velocities through the endarterectomized segment with no evidence of residual plaque. The patient remains stable 4 months postoperatively.
Discussion
Operative management of carotid in-stent restenosis presents a technical challenge to the vascular surgeon, and our series highlights the need for multiple treatment strategies for this problem. Optimal management of restenosis following carotid artery stenting has not yet been established. Because the majority of patients undergoing CAS are deemed high risk for an open operation, secondary endovascular interventions for recurrent stenosis have been advocated by several recent series.2, 3, 5 Leger and colleagues,1 however, reported significant (>60%) recurrent stenoses in 75% of patients over a mean follow-up period of 20.2 months following CAS. Skelly et al.6 demonstrated only a 27 ± 17% freedom from in-stent restenosis at 24 months for patients with a history of prior neck cancer. Another recent series demonstrated restenosis rates of 10.5% and 20% at 24 months in patients with prior CEA and neck irradiation, respectively.7
All four patients in our series demonstrated inflammatory changes in tissues adjacent to the stented artery, which added to the complexity of intraoperative dissection. This process has been observed in patients undergoing balloon angioplasty with stent placement in various anatomic locations and has been implicated as a possible factor contributing to restenosis.8, 9, 10, 11 Because normal dissection planes may not be present in these patients, added care must be taken to avoid nerve and venous injuries. This issue becomes especially relevant in cases where the arterial segment containing the stent is circumferentially dissected and removed prior to surgical bypass. In case 2, where complete removal of the arterial/stent segment was performed, our estimated blood loss was significant (200 cc) and greater than the other three cases in which estimated blood loss was minimal. Identification of the vagus and hypoglossal nerves, which may be adherent to the arterial wall, must also be made.
The degrees of stent incorporation within the arterial wall may also require different surgical strategies. Two patients in our series demonstrated recurrent atherosclerotic plaque within the stent, which resulted in critical luminal stenosis. The patient described in the first case was found to have a completely incorporated stent encased in neointima. Because removal of the stent was not possible without complete removal of the arterial segment, the anterior wall of the artery and stent were easily incised quite easily with Mayo scissors, and patch angioplasty with a Dacron hemashield patch was performed. We were able to restore flow without surgical bypass. To our knowledge, this is the first report of this technique. Long-term patency of this technique is unknown.
The patient in the fourth case had a minimally incorporated CAS, so we were able to develop a typical endarterectomy plane between the intima and the internal elastic lamina. Removal of the plaque and stent and patch angioplasty was performed. This technique may also allow recanalization of a chronically occluded ECA.
Thus, in cases of minimal stent incorporation, endarterectomy and complete stent removal is favored. In cases where the stent is too well incorporated for removal, excision of the anterior wall of the artery and stent (without complete stent removal) and patch angioplasty is preferable. Surgical bypass should be performed in the presence of long-segment in-stent occlusions of the CCA and ICA, when a patent extracranial ICA is present. In situations where the occlusion is located in the proximal CCA, the subclavian artery may be the inflow vessel of choice. The long-term safety and durability of prosthetic grafts for carotid artery reconstruction have been well established.12, 13 They eliminate the need for vein harvest and provide a good size match with native artery in most cases. Bypass avoids exposure of the CCA or ICA in the presence of likely surrounding inflammation of the stented artery.
Another technical consideration is exposure of the distal ICA due to high stent placement. The location and number of stents in these patients is highly variable. Surgeons performing carotid reconstruction following stent placement should be prepared to perform maneuvers for exposure of the high ICA, including nasotracheal intubation, division of the posterior belly of the digastric muscle, division of the nerve to the carotid sinus, and subluxation of the mandible. None of these was required in our series. Preoperative localization of the stent is useful; however, in patient 4, the stent was not visualized on duplex ultrasound prior to the operation.
Conclusion
With increasing use of CAS, there will be an increasing need for secondary procedures following failure of CAS. Vascular surgeons will be faced with increased numbers of complications from these procedures as well as in-stent restenoses which have failed repeated endovascular procedures. We describe four different techniques for operative management of carotid restenosis following angioplasty and stenting. Inflammatory changes surrounding the artery containing the stent make dissection more difficult. Normal tissue planes should not be expected. The possibility of high ICA exposure exists because stent location is highly variable. Although classic endarterectomy of the plaque and stent should be a goal in the treatment of CAS restenosis, arteriotomy and excision of the anterior wall of the stent and artery with patch angioplasty is technically feasible.
Bypass grafts from the common and subclavian arteries to the distal ICA are technically feasible and may be necessary for CAS occlusion. Short-term results for CAS restenosis surgery are excellent; larger series with long-term results will be needed to determine the optimal treatment of CAS restenosis using endarterectomy, patch angioplasty alone, or bypass.
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This article was presented at the 25th Annual Meeting of the Southern California Vascular Society, Coronado, California, May 5th, 2007.
PII: S0890-5096(07)00304-4
doi:10.1016/j.avsg.2007.08.002
© 2008 Annals of Vascular Surgery Inc. Published by Elsevier Inc All rights reserved.
