Factors contributing to recurrent carotid disease following carotid endarterectomy

The management of carotid restenosis: a comprehensive review

Carotid artery stenosis (CS) is a major medical problem affecting approximately 10% of the general population 80 years or older and causes stroke in approximately 10% of all ischemic events. In patients with symptomatic, moderate-to-severe CS, carotid endarterectomy (CEA) and carotid angioplasty and stenting (CAS), has been used to lower the risk of stroke. In primary CS, CEA was found to be superior to best medical therapy (BMT) according to 3 large randomized controlled trials (RCT). Following CEA and CAS, restenosis remains an unsolved problem involving a large number of patients as the current treatment recommendations are not as clear as those for primary stenosis. Several studies have evaluated the risk of restenosis, reporting an incidence ranging from 5% to 22% after CEA and an in-stent restenosis (ISR) rate ranging from 2.7% to 33%. Treatment and optimal management of this disease process, however, is a matter of ongoing debate, and, given the dearth of level 1evidence for the management of these conditions, the relevant guidelines lack clarity. Moreover, the incidence rates of stroke and complications in patients with carotid stenosis are derived from studies that did not use contemporary techniques and materials. Rapidly changing guidelines, updated techniques, and materials, and modern medical treatments make actual incidence rates barely comparable to previous ones. For these reasons, RCTs are critical for determining whether these patients should be treated with more aggressive treatments additional to BMT and identifying those patients indicated for surgical or endovascular treatments. This review summarizes the current evidence and controversies concerning the risks, causes, current treatment options, and prognoses in patients with restenosis after CEA or CAS.

Restenosis after carotid artery stenting

As a common etiology for ischemic stroke, atherosclerotic carotid stenosis has been targeted by vascular surgery since 1950s. Compared with carotid endarterectomy, carotid angioplasty and stenting (CAS) is almost similarly efficacious and less invasive. These advantages make CAS an alternative in treating carotid stenosis. However, accumulative evidences suggested that the long-term benefit-risk ratio of CAS may be decreased or even neutralized by the complications related to in-stent restenosis (ISR). Therefore, investigating the mechanisms and identifying the influential factors of ISR are of vital importance for improving the long-term outcomes of CAS. As responses to intrinsic and extrinsic injuries, intimal hyperplasia and vascular smooth muscle cell proliferation have been regarded as the principle mechanisms for ISR development. Due to the lack of consensus-based definition and consistent follow-up protocol, the reported incidences of ISR after CAS varied widely among studies. These variations made the inter-study comparisons of ISR largely illogical. To eliminate restenosis after CAS, both surgery and endovascular procedures have been attempted with promising results. For preventing ISR, drug-eluting stents and antiplatelets have been proposed as potential solutions.

Carotid Artery Stenting with Distal Protection Using the Carotid Wallstent and Filterwire Neuroprotection: Single-Center Experience of 380 Cases with Midterm Outcomes

Emerging data have supported the clinical efficacy of carotid artery stenting (CAS) in stroke prevention in high-risk surgical patients. This study was performed to evaluate the midterm clinical outcome of CAS using the Carotid Wallstent and FilterWire distal protection (both Boston Scientific, Natick, MA) at an academic institution. Risk factors for in-stent restenosis (ISR) were also analyzed. Clinical variables and treatment outcome of high-risk patients who underwent Carotid Wallstent placement with FilterWire EX/EZ neuroprotection were analyzed during a recent 54-month period. Three hundred eighty CAS procedures were performed in 354 patients. Technical success was achieved in 372 cases (98%), and symptomatic lesions existed in 85 (24%) patients. No patient experienced periprocedural mortality or neuroprotective device–related complication. The 30-day stroke and death rate was 2.7%, and the overall complication rate was 6.9%. The overall major or fatal stroke rates in symptomatic and asymptomatic patients were 4.6% and 1.3%, respectively (not significant). The overall stroke and death rates between the symptomatic and asymptomatic groups were 5.8% and 2.4%, respectively (not significant). The median follow-up period was 29 months (range 1–53 months). With Kaplan-Meier analysis, the rates of freedom from 60% or greater ISR after CAS procedures at 12, 24, 36, and 48 months were 97%, 94%, 92%, and 90%, respectively. The rates of freedom from all fatal and nonfatal strokes at 12, 24, 36, and 48 months were 97%, 91%, 89%, and 85%, respectively. Multivariable analysis of significant univariate predictors identified that postendarterectomy stenosis (odds ratio [OR] 3.98, p = .02) and multiple stent placement (OR 3.68, p = .03) were independent predictors of ISR. Our study yielded favorable short-term and midterm clinical results using Carotid Wallstent with FilterWire neuroprotection. Late follow-up results showed low rates of fatal and nonfatal stroke and favorable ISR rates compared with other carotid stent trials. Postendarterectomy and multiple stent placement were associated with subsequent ISR.

Characteristic sonographic findings of early restenosis after carotid endarterectomy

OBJECTIVE

Restenosis of the carotid artery after carotid endarterectomy (CEA) is a major complication. The frequency, time of occurrence, and tissue characteristics of carotid restenosis were assessed with sonography.

METHODS

Two hundred sixteen patients who had CEA for carotid stenosis were studied; follow-up sonography and magnetic resonance angiography were done 2 weeks, 3 months, and then every year after CEA. On sonography, restenosis was defined as an internal carotid artery (ICA) with a peak systolic velocity of 170 cm/s or greater or a maximum area of stenosis of 90% or greater.

RESULTS

During 605 artery-years of follow-up, 18 patients (7.5%) were found to have restenosis on sonography: 4 at 3 months, 11 at 1 year, and 3 at 2 years after CEA. At the time that restenosis was detected, in all 18 ICAs the peak systolic velocity exceeded 200 cm/s and had more than doubled since the last measurement (mean +/- SD, 103 +/- 27 to 321 +/-107 cm/s), whereas the area of stenosis exceeded 90% in 6 patients, and magnetic resonance angiography revealed stenosis of 60% or greater in 8 patients. On sonography, all of the restenotic plaques were isoechoic and concentric. The restenosis was asymptomatic in 17 patients. Vascular risk factors or the severity of initial carotid stenosis before CEA were not associated with development of restenosis. Eleven patients had successful endovascular therapy, and the others received medical treatment.

CONCLUSIONS

A marked increase in the flow velocity through an operated ICA is a good indication of restenosis. The isoechogenicity and concentricity of the restenotic plaques suggest that the restenosis is primarily the result of intimal hyperplasia.

Low c1-inhibitor levels predict early restenosis after eversion carotid endarterectomy

OBJECTIVE

Homozygotes for the normal (A) allele of mannose-binding lectin (MBL2) gene have higher risks to develop an early restenosis after eversion carotid endarterectomy (CEA). Activation of the lectin pathway is regulated by C1-inhibitor (C1-INH). The objective of the present study was to determine the predictive value of C1-INH in restenosis after CEA.

METHODS AND RESULTS

C1-INH and MBL-associated serine protease-2 (MASP-2) were determined in samples serially taken from 64 patients with CEA, who were followed-up with carotid duplex scan (CDS) examinations for 14 months. MBL2 genotypes were also determined. Patients with >50% restenosis had lower C1-INH levels at 6 weeks (P=0.0052) and at 4 days (P=0.0277) postsurgery. C1-INH levels at 6 weeks correlated inversely with the CDS values at 14 months (r=-0.3415, P=0.0058), but only in MBL2 A/A homozygotes (r=-0.5044, P=0.0015). Patients with low C1-INH levels (C1-INH <115%) had higher CDS values already at 7 months postsurgery. Patients with MBL2 A/A and low C1-INH levels at 6 weeks postsurgery had 13.97 (95% CI:1.95 to 100.21, P=0.0087) times higher risk to develop an early restenosis. Differences in the MASP-2 concentration were not associated with restenosis.

CONCLUSIONS

Determining C1-INH levels at 6 weeks postsurgery-together with genotyping of MBL2-might be a useful marker in the identification of patients with high risk for early carotid restenosis.

Carotid angioplasty and stenting versus redo endarterectomy for recurrent stenosis

BACKGROUND

Carotid angioplasty and stent (CAS) is an alternative to redo carotid endarterectomy (RCEA) for recurrent carotid stenosis (RCS). The purpose of this study was to evaluate the outcomes of CAS in the treatment of RCS.

METHODS

In an 8-year period, all patients presenting for treatment of RCS were followed-up prospectively. Logistic regression analysis was performed to identify variables associated with unfavorable outcomes.

RESULTS

There were 45 CAS and 46 RCEA procedures performed in 75 patients. One patient in each group suffered a stroke. There were no deaths. The hospital length of stay was significantly shorter for CAS. Secondary recurrence was higher after RCEA (14% vs 6.1%) and failure to take beta-blockers was an independent predictor for multiple recurrences.

CONCLUSIONS

CAS is a safe and effective method to treat patients with RCS and may become the procedure of choice for this disease.

Carotid Clamping Time as a Risk Factor for Early Restenosis After Carotid Endarterectomy

OBJECTIVE

The aim of our study was to identify risk factors for early restenosis after carotid endarterectomy (CEA).

METHODS

Prospective follow-up of 497 primary CEAs was performed at 3, 6, 12 and 24 months by clinical assessment and duplex ultrasound to identify > or = 50% restenosis.

RESULTS

Early restenosis occurred in 71 (14.3%) patients. By univariate analysis high carotid clamping time (CCT) (p = 0.002) and absence of shunt use (p = 0.03) were related to early restenosis. High CCT was the only independent predictor of early restenosis in a forward stepwise logistic regression model (OR = 2.25; CI 1.2-4.1; p = 0.008).

CONCLUSIONS

Carotid clamping time may be a novel risk factor for early restenosis.

Safety and durability of redo carotid operation: an 11-year experience

PURPOSE

With the recent emergence of carotid stenting in the management of carotid disease, the role of surgery has been challenged, particularly for recurrent carotid stenosis. This study was undertaken to determine the safety and durability of redo carotid operation (RCO) for recurrent stenosis.

METHODS

A retrospective review identified 64 consecutive patients who underwent 66 RCOs between 1990 and 2000. There were 33 males (52%) and 31 females, with a mean age of 68.2 years (range, 38-84 years). The mean interval from the primary carotid surgery to RCO was 77.5 months (range, 1-292 months). Operative indications were severe asymptomatic stenosis in 33 cases (50%), transient ischemic attacks (TIA) or amaurosis fugax in 25 (38%), recent stroke in 6 (9%), and nonhemispheric symptoms in 1. Two operations were tertiary carotid reconstructions. A total of 56 (85%) patch angioplasties were performed, 49 with vein and 6 with synthetic material. Primary closure was performed in three cases (5%), whereas interposition grafts were required in eight (12%). Complete follow-up was available in 59 patients (92%) and averaged 4.3 years (range, 0.2-12.9 years); 97% of patients underwent follow-up duplex scanning.

RESULTS

There were no operative deaths and only two operative strokes (3.1%). Permanent cranial nerve deficit occurred in one patient (1.5%). Late stroke occurred in five patients: four ipsilateral and one contralateral. Kaplan-Meier estimates for 5- and 10-year stroke-free survival were 92% and 74%, and for overall survival were 72% and 50%. Duplex scanning detected significant recurrent carotid stenosis (>80%) or occlusion in six cases (9%) at a mean follow-up of 4.1 years. Kaplan-Meier estimates for freedom from recurrent stenosis of >80% were 94% and 86% at 5 and 10 years.

CONCLUSIONS

RCO for recurrent carotid stenosis can be performed safely with excellent protection from stroke and long-term durability. These data provide a standard against which the results of carotid stenting can be compared.

Predictors of restenosis after successfulcarotid artery stenting

This study was performed to determine the risk factors for restenosis after successful carotid stenting. Of 222 patients who underwent successful carotid stenting, 179 (81%) had a follow-up study (carotid ultrasound and/or angiogram). Restenosis rate was 6.7% (14 of 195) for vessels. By univariate analysis, restenosis rates were significantly different between men and women (4% vs 15.4%, p = 0.018) and age < or =75 versus >75 years (3.8% vs 16%, p = 0.013). By multivariate analysis, older age (odds ratio [OR] 1.107, p = 0.015), female sex (OR 3.519, p = 0.001), implantation of multiple stents (OR 2.363, p = 0.019), and postprocedural percent stenosis (OR 1.067, p = 0.054) were associated with increased incidence of restenosis.

Gender does not influence outcomes after iliac angioplasty

The current study was undertaken to evaluate the potential influence of gender on iliac angioplasty outcomes. All iliac angioplasty procedures performed at a tertiary care center from 1994 to 1999 were reviewed. One hundred four angioplasties with or without stenting were performed in 44 women (56 limbs) and 40 men (48 limbs). Age and atherosclerotic risk factors were similar in men and women. Iliac angioplasty was performed for limb salvage in 41% of patients (39% female vs. 44% male; p = 0.65). There were no differences in degree of stenosis, lesion length, or initial angioplasty site. Female iliac arteries were more likely to be occluded (21% vs. 6%; p = 0.03); mean iliac artery luminal diameter was smaller in women than in men (6.5 +/- 0.5 mm vs. 8.2 +/- 0.6 mm; p < 0.001). After a median follow-up of 13 months, there were no significant differences in 2-year primary patency, endovascular primary-assisted patency, or limb salvage rates between women and men. Despite having smaller iliac arteries and a higher incidence of arterial occlusion before treatment, women had outcomes similar to those of men after iliac angioplasty. The current results support the initial use of angioplasty to treat common and external iliac artery occlusive disease in both women and men.

Carotid artery patch angioplasty: impact and outcome

Our study objective was to determine if patch angioplasty after carotid endarterectomy decreases the incidence of post-reconstruction technical defects and recurrent stenosis. This was a retrospective review of a prospectively maintained database from February 1980 to February 2000. Main outcome measures included incidence of intraoperative technical defects, residual disease within 3 months of endarterectomy, and early/late carotid restenosis >50%. During the study period, 71% (1053) of patients had primary closure and 29% (435) had patch closure. Immediate post-reconstruction intraoperative imaging with angiography or duplex ultrasound was accomplished in all cases. Technical defects prompted the reopening of 136 (13%) carotid arteries closed primarily but only 9 (2%) of those that were patched (p < 0.0001). There were no instances of residual disease in either group. Overall rate of recurrent stenosis was 2%, 3%, and 3.5% at 5, 10, and 15 years, respectively by life-table analysis. Early and late restenosis was significantly reduced by patch angioplasty (p = 0.024 and 0.006, respectively). This study demonstrates that carotid artery patch angioplasty significantly reduces the incidence of detectable technical defects and the early/late recurrent stenosis rate.

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.

Recurrent carotid stenosis : results of the asymptomatic carotid atherosclerosis study

BACKGROUND AND PURPOSE

We sought to determine the incidence of recurrent carotid stenosis in patients in the Asymptomatic Carotid Atherosclerosis Study (ACAS) who had undergone carotid endarterectomy and were prospectively followed with Doppler ultrasound for up to 5 years.

METHODS

The ACAS database was interrogated to determine the rate of recurrent carotid stenosis (>/=60%) based up angiogram-validated Doppler data, with a 90% and a 95% positive predictive value, as well as information concerning the technologists' interpretation of percent stenosis. These 3 parameters are reported for each of 3 time intervals: within 3 months of operation (residual disease), between 3 and 18 months (early restenoses), and between 18 and 60 months (late restenosis).

RESULTS

Of the 825 patients randomized to the surgical arm of the study, 720 actually underwent carotid endarterectomy, and 645 had complete ultrasound data. The aggregate incidence of residual and recurrent carotid stenosis for all time intervals ranged from 12.7% to 20.4%, depending on the positive predictive value confidence level desired. Residual disease occurred in 4.1% to 6.5%; true, early restenosis was found in 7.6% to 11.4%; and late restenosis occurred in 1.9% to 4.9%. None of the traditional risk factors showed a statistically significant effect on recurrent stenosis. The use of patch angioplasty closure reduced overall risk of restenosis from 21.2% to 7.1%, from 16.7% to 4.6%, and from 27.4% to 8.2%, depending on the PPV confidence level desired (P<0.001). Of the 136 patients judged to have recurrent stenosis, only 8 (5.9%) underwent reoperation (only 1 for symptoms). There was no correlation between late stroke and recurrent stenosis.

CONCLUSIONS

Carotid endarterectomy is a durable procedure with a low rate of true restenosis, particularly when patch angioplasty is used to close the arteriotomy.