The influence of smoking and lipids on restenosis after carotid endarterectomy

A retrospective study on the preventive effect of statin after carotid artery stenting

This retrospective study appraised the preventive effect of statin after carotid artery stenting (CAS).Records were extracted for 100 patients with CAS surgery indicator, aged between 20 and 75 years old, and treated for statin. The cohort study included treatment group (statin and routine treatment) and control group (routine treatment), each group 50 patients. Outcomes consisted of degree of nerve defect (as measured by National Institute of Health Stroke Scale), lipid profiles (mg/dL), and CAS complications within 30 days after surgery.After treatment, there were no significant differences in National Institute of Health Stroke Scale, lipid profiles, and mortality rate between 2 groups. However, significant differences in total cholesterol (mg/dL, P = .03), low-density lipoprotein (mg/dL, P = .01), transient ischemic attack (P = .03), ischemic stroke (P = .04), and cardiac complications (P = .03) were identified within 30 days after CAS between 2 groups.The results of this study showed that prior statin treatment may be effective for the prevention of CAS complications.

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.

Effects of patient age on outcomes after carotid endarterectomy: A retrospective, single-center study in Korea

In this single-center, retrospective study, we aimed to compare early and late outcomes after carotid endarterectomy (CEA) between younger and elderly patients and to investigate the impact of patient age on the overall incidence of cardiovascular events after CEA.A total of 613 patients with 675 CEAs between January 2007 and December 2014 were stratified by patient age into 2 groups: younger (≤60 years, n = 103 CEAs, 15.3%) and elderly (>60 years, n = 572 CEAs, 84.7%) groups. The study outcomes were defined as the occurrence of major adverse events (MAEs), including fatal or nonfatal stroke or myocardial infarction (MI), or any-cause mortality, and overall cardiovascular events (meaning the composite incidence of stroke or MI) during the perioperative period and within 4 years after CEA.Although there were no significant differences in the incidence of 30-day MAEs and any of the individual MAE manifestations between the 2 groups, the differences in the MAE incidence (P = .006) and any-cause mortality (P = .023) within 4 years after CEA were significantly greater in patients in the elderly group. For overall incidence of cardiovascular events, no significant difference was noted between the 2 groups (P = .096). On multivariate analysis, older age (>60 years) did not affect the incidence of perioperative MAEs and individual MAE manifestations; however, older age was significantly associated with an increased risk of 4-year MAEs (hazard ratio [HR], 3.68, 95% confidence interval [CI], 1.35-10.0; P = .011) and any-cause mortality (HR, 3.26, 95% CI, 1.02-10.5; P = .047). With regard to the 4-year overall incidence of cardiovascular events, older age was not an independent predictor of increased risk of these cardiovascular events.Our study indicates that the risks of perioperative MAEs and the 4-year overall incidence of cardiovascular events do not significantly differ between younger and elderly Korean patients undergoing CEA, although there was a higher risk of 4-year any-cause mortality in the elderly patients. Older age does not appear to be an independent risk factor for perioperative MAEs and overall cardiovascular events within 4 years after CEA.

Platelet Aggregability as a Predictor of Restenosis Following Carotid Endarterectomy

BACKGROUND

Antiplatelet drugs are administered before and after carotid endarterectomies (CEAs), but their efficacy for preventing restenosis remains unclear. Hence, this study aimed to identify associations between postoperative restenosis and platelet aggregability in CEA patients.

METHODS

Thirty-six consecutive CEA patients treated at Tokyo Women's Medical University from May 2013 to March 2015 were included in this retrospective study. Restenosis was defined as a stenosis ratio greater than or equal to 50% per the European Carotid Surgery Trial criteria or peak systolic velocity of 150 cm/s on carotid ultrasound. Platelet aggregability was measured turbidimetrically using a light-transmission platelet aggregometer and analyzed in terms of aggregation profiles for 2 concentrations of collagen used to induce aggregation (.25 and 2.0 μg/mL). Patients were automatically divided into 9 classes (Class 1-9, from the lowest to the highest aggregability) using a software program according to area under their platelet aggregation curves. Each class was subdivided into 10 further gradations for a total of 90 possible scores (10-99) using a software program. Patients were divided into high- and low-platelet aggregability score groups (cut-off = 49).

RESULTS

Data were analyzed for 36 of the 99 patients. Restenosis was observed in 10 (28%) patients. Restenosis incidence was significantly higher in patients with high-platelet aggregability score than in those with low-platelet aggregability score (50.0% [7/14] versus 13.6% [3 of 22]: P = .0176, odds ratio = 6.34, 95% CI: 1.27-31.57).

CONCLUSIONS

Platelet aggregability is a useful metric for predicting and preventing restenosis after CEA. It has potential as an indicator for determining the optimal dose of antiplatelet drugs.

Do standard carotid artery endarterectomy and primary closure technique cause early restenosis in diabetic patients?

Introduction

We aimed to investigate carotid restenosis in 2-year follow-up in diabetic and nondiabetic patients who underwent standard carotid endarterectomy with primary carotid closure and determine whether diabetes mellitus is a risk factor for early stenosis for this surgical procedure.

Material and methods

We retrospectively assessed the data of patients who underwent standard carotid endarterectomy with primary carotid closure from the hospital registry and outpatient clinic follow-up between January 2006 and January 2012. The study included 25 diabetics and 25 nondiabetics, in total 50 patients. The control carotid Doppler ultrasonographies and/or computed tomography angiographies of the patients at postoperative 1, 6, 12, and 24 months were examined and a stenosis rate between 70% and 99% was regarded as significant carotid restenosis.

Results

When the diabetic and nondiabetic group patients were compared for early carotid restenosis at 2 years, there were 3 (12%) patients in the diabetic group and 4 (16%) patients in the nondiabetic group with restenosis. A statistically significant difference in early carotid restenosis was not observed between the two groups (p > 0.05).

Conclusions

Standard carotid endarterectomy and primary closure of the artery is a successfully performed surgical procedure in diabetic patients. We concluded that diabetes mellitus is not a risk factor for early restenosis in the diabetic patient population according to the results of our research.

Decreased Antioxidant Vitamin Concentration May Be a Risk Factor for Recurrent Carotid Stenosis

Carotid endarterectomy has been found to be associated with a transient increase in systemic oxidative stress, and this has been shown to be a predictor of restenosis. The aim of this study was to determine the incidence of early recurrent stenosis and investigate a possible role of oxidative stress in its development by measuring the concentration of antioxidant vitamins. Patients undergoing carotid endarterectomy between August 2001 and February 2003 were included in the study. A preoperative blood sample was analyzed for antioxidant vitamin concentrations. All patients were followed up by duplex scans 3 and 12 months postoperatively. Ninety-three patients (101 carotid endarterectomies) were recruited. Nine arteries had developed restenosis by 12 months. Those patients who developed recurrent stenosis had significantly lower vitamin C concentrations (19.10 ± 3.69 vs 30.11 ± 19.10, P = .02) than those who did not. This study suggests that low antioxidant vitamin levels may predispose to early restenosis after carotid endarterectomy.

Restenosis After Carotid Endarterectomy: Insight Into Risk Factors and Modification of Postoperative Management

BACKGROUND

Restenosis after carotid endarterectomy (CEA) is a potential complication after surgery for carotid stenosis. Stroke after CEA is a debilitating complication secondary to restenosis, and modification of postoperative care may be necessary to decrease the incidence of postoperative stroke after CEA. We sought to identify the clinical and patient factors that are associated with this complication.

METHODS

A retrospective analysis of all neurosurgical patients who underwent CEA for symptomatic or asymptomatic carotid stenosis was performed. Factors were compared against the outcome variable in a univariate analysis. A multivariate logistic regression model was used to identify independent predictive variables. We used Kaplan-Meier analysis to compare the effect of the variables on long-term event-free survival.

RESULTS

A total of 273 CEA procedures and their outcomes were analyzed with a mean follow-up of 50.7 months. Twenty-one patients had restenosis (7.6%). Rates of restenosis and restenosis-free survival were analyzed with Kaplan-Meier curves (log-rank test). In the multivariate model, a family history of stroke was the only variable that was significantly associated with restenosis after CEA.

CONCLUSIONS

Our findings suggest that a family history of stroke is an important factor that predisposes patients to restenosis after CEA. Restenosis-free survival is influenced by the presence of hyperlipidemia, age, and family history of stroke. Closer surveillance with more frequent follow-up and multidisciplinary management may be beneficial in patients who have these risk factors to prevent restenosis and prolong restenosis-free survival.

Preventing restenosis in early drug-eluting stent era: recent developments and future perspectives

Restenosis is the major limitation of the successful therapy of percutaneous coronary intervention (PCI) for patients with coronary artery disease. The problem was appreciated in the late 1970s to early 1980s. Only in recent years, anti-restenotic therapy has achieved a breakthrough with the development of drug-eluting stents. Here, we provide an overview about pathological mechanisms of restenosis after PCI. Present therapeutic approaches to overcome restenosis and recent clinical results are revisited, and some major concerns in the post-drug-eluting stent era are discussed.

Have statins changed the natural history of atheromatous disease and its treatment?

Statins are among the most widely prescribed medications in the world and there are now numerous clinical trials demonstrating the beneficial effects of these medications on the natural history of atheromatous disease and its treatment. There is now voluminous data to show that patients treated by vascular surgeons benefit from statins and that these medications do effect the natural history of atheroma, its consequences, and treatment. This article will attempt to summarize the more relevant data that highlights the beneficial effects of statins in patients with peripheral arterial disease and how use of these drugs affects cardio-, peripheral, and cerebrovascular risk.

The Role of Statin Drugs in the Management of the Peripheral Vascular Patient

The impact of statin therapy on established vascular conditions and recurrent disease is most relevant for long-term care. Patients receiving statin therapy have been shown to experience less recurrent stenosis following carotid endarterectomy and stent angioplasty, reduced cardiac events following cardiac and noncardiac vascular surgery, and reduction in aneurysm development. In patients with peripheral arterial disease, claudication distance is increased, as well as patency rates following infrainguinal arterial bypass grafting. Of note, statins drugs may also prove beneficial in the prevention of certain cancers, Alzheimer's disease, and osteoporosis (all diseases frequently seen concurrently in the patient with peripheral arterial disease). As such, it is becoming all the more necessary that vascular surgeons remain informed about clinical research initiatives related to statin use and lipid management in general. The following is a review of lipid metabolism as it applies to statins as well as a review of the beneficial effects of statins.

Primary Closure After a Carotid Endarterectomy

PURPOSE

The prevalences of restenosis and stroke after a carotid endarterectomy (CEA) tend to differ substantially according to the surgeon. Primary closure after a CEA was the routine procedure in our institute. The primary objectives of this study were to compare the results of patients of a primary arteriotomy closure in CEA between our own and others' results based on the findings in the literature.

METHODS

One hundred and sixty-six patients who underwent a primary closure were analyzed. Perioperative neurologic deficits were determined by the neurologist. Restenosis was defined as >50% stenosis on duplex scan. The range of follow-up was 7-112 months.

RESULTS

Stroke including transient ischemic attack occurred within 30 postoperative days in 3 patients and after 30 postoperative days in 1 of the 166 patients. Five patients showed >50% asymptomatic restenosis. Two patients were treated with stent insertion and one underwent reoperation. One patient showed total occlusion during the follow-up period without any neurological deficits. One patient showed 50%-70% stenosis, and no intervention was done.

CONCLUSIONS

The rates of recurrent stenosis and postoperative stroke were found to be sufficiently low following a primary closure to justify the continued use of this technique.

Determinants of carotid endarterectomy anatomic durability: Effects of serum lipids and lipid-lowering drugs

OBJECTIVES

Carotid endarterectomy (CEA) remains the gold standard for treatment of carotid stenosis. With inevitable comparisons of catheter-based therapy to all aspects of CEA, this study of a large contemporary series was undertaken to evaluate the determinants of anatomic durability of CEA.

METHODS

During the interval (1989 through 1999), 2,127 primary, isolated CEAs with selective patching (50.2%) were performed in 1,853 patients (61.8% male, 36.1% symptomatic). End points included patient longevity and perioperative morbidity as well as evidence of CEA anatomic durability as defined by duplex evaluation: CEA restenosis (moderate, >50%, or greater recurrent stenosis), which included CEA anatomic failure (severe, >70%, restenosis/carotid occlusion). The incidence of CEA recurrent stenosis was temporally assessed early (<2 years) and late (>2 years) after operation. Clinical and surgical variables potentially associated with the study endpoints were analyzed by univariate and multivariate methods.

RESULTS

The perioperative stroke and death rate was 1.4% and the 2-year and 10-year survival was 88.1% and 44.9%, respectively. Anatomic failure after CEA developed in 3.9% at 2 years and in 8.5% at 5 years; only 3.2% of CEA patients underwent reoperation during a mean follow-up of 73.4 months. Early (<2 years) analysis revealed 12.2% restenosis, whereas late (>2 years) results identified 9.8% progression of carotid stenosis and a 5.8% rate of anatomic failure. Multivariate analysis determined elevated creatinine (odds ratio [OR], 1.719, P < .001) and female gender (OR, 1.564; P < .02) correlated with early restenosis. Surgical patch closure and lipid-lowering drugs were protective for both early restenosis, with ORs of 0.543 (P < .0.001) and 0.601 (P < .007) and early anatomic failure ORs of 0.469 (P < .02) and 0.517 (P < .03), respectively. Although only elevated serum cholesterol (OR, 1.009; P < .03) correlated with late anatomic failure, only lipid-lowering drugs were protective for both late freedom from progression of disease (OR, 0.202; P < .0002) or late CEA anatomic failure (OR, 0.128; P < .0003).

CONCLUSIONS

The association of female gender and elevated cholesterol with recurrent carotid stenosis is confirmed, elevated creatinine is introduced as a risk factor, and surgical patch repair is protective for early CEA recurrent carotid stenosis. The unique findings of the significant, beneficial effects of lipid-lowering drugs on both early and late CEA anatomic durability and patient survival indicate that such therapy should be instituted in most patients after CEA.

Frequency and management of recurrent stenosis after carotid artery stent implantation

Object. To determine the rate of hemodynamically significant recurrent carotid artery (CA) stenosis after stent-assisted angioplasty for CA occlusive disease, the authors analyzed Doppler ultrasonography data that had been prospectively collected between October 1998 and September 2002 for CA stent trials.

Methods. Patients included in the study participated in at least 6 months of follow-up review with serial Doppler studies or were found to have elevated in-stent velocities (> 300 cm/second) on postprocedure Doppler ultrasonograms. Hemodynamically significant (≥ 80%) recurrent stenosis was identified using the following Doppler criteria: peak in-stent systolic velocity at least 330 cm/second, peak in-stent diastolic velocity at least 130 cm/second, and peak internal carotid artery/common carotid artery velocity ratio at least 3.8. Follow-up studies were obtained at approximate fixed intervals of 1 day, 1 month, 6 months, and yearly. Angiography was performed in the event of recurrent symptoms, evidence of hemodynamically significant stenosis on Doppler ultrasonography, or both. Treatment was repeated because of symptoms, angiographic evidence of severe (≥ 80%) recurrent stenosis, or both of these.

Stents were implanted in 142 vessels in 138 patients (all but five patients were considered high-risk surgical candidates and 25 patients were lost to follow-up review). For the remaining 112 patients (117 vessels), the mean duration of Doppler ultrasonography follow up was 16.42 ± 10.58 months (range 4–54 months). Using one or more Doppler criteria, severe (≥ 80%) in-stent stenosis was detected in six patients (5%). Eight patients underwent repeated angiography. Six patients (three with symptoms) required repeated intervention (in four patients angioplasty alone; in one patient conventional angioplasty plus Cutting Balloon angioplasty; and in one patient stent-assisted angioplasty).

Conclusions. In a subset of primarily high-risk surgical candidates treated with stent-assisted angioplasty, the rates of hemodynamically significant restenosis were comparable to surgical restenosis rates cited in previously published works. Treatment for recurrent stenosis incurred no instance of periprocedure neurological morbidity.

Carotid endarterectomy at the millennium: what interventional therapy must match

OBJECTIVES

Carotid endarterectomy (CEA) is supported by level 1 evidence as the standard treatment of severe carotid stenosis in both symptomatic and asymptomatic patients. As interventional techniques are emerging for treatment of this disease, this study was undertaken to provide a contemporary surgical standard for comparison to carotid stenting.

PATIENTS AND METHODS

During the interval 1989 to 1999, 2236 isolated CEAs were performed on 1897 patients (62% male, 36% symptomatic, 4.6% reoperative procedures). Study endpoints included perioperative events, patient survival, late incidence of stroke, anatomic durability of CEA, and resource utilization changes during the study. Variables associated with complications, long-term and stroke free survival, restenosis, and resource utilization were analyzed by univariate and multivariate analysis.

RESULTS

Perioperative complications occurred in 5.5% of CEA procedures, including any stroke/death (1.4%), neck hematoma (1.7%), cardiac complications (0.5%), and cranial nerve injury (0.4%). Actuarial survival at 5 and 10 years was 72.4% (95% confidence interval [CI] 69.3-73.5) and 44.7% (95% CI 41.7-47.9) respectively, with coronary artery disease (P < 0.0018), chronic obstructive pulmonary disease (P < 0.00018) and diabetes mellitus (P < 0.0011) correlating with decreased longevity. The age- and sex-adjusted incidence of any stroke during follow-up was reduced by 22% (upper 0.35, lower 0.08) of predicted with the patient classification of hyperlipidemia (P < 0.0045) as the only protective factor. Analysis of CEA anatomic durability during a median follow-up period of 5.9 years identified a 7.7% failure rate (severe restenosis/occlusion, 4.5%; or reoperative CEA, 3.2%) with elevated serum cholesterol (P < 0.017) correlating with early restenosis. Resource utilization diminished (first versus last 2-year interval periods) for average hospital length of stay from 10.3 +/- 1.5 days to 4.3 +/- 0.7 days (P < 0.01) and preoperative contrast angiography from 87% +/- 1.4% to 10.3% +/- 4%.

CONCLUSIONS

These data delineate the safety, durability, and effectiveness in long-term stroke prevention of CEA. They provide a standard to which emerging catheter-based therapies for carotid stenosis should be compared.

Vascular nurse as a smoking cessation specialist

Cigarette smoking is a leading cause of disease and preventable death in the United States and is a major contributing factor to the development and progression of peripheral arterial disease. Vascular risk decreases immediately after smoking cessation and within 5-10 years reaches a level almost equivalent to that in nonsmokers. Despite the strong emphasis on smoking cessation, relapse frequently occurs. Smoking relapse is affected by physiologic and psychosocial factors. As a smoking cessation specialist, the vascular nurse can incorporate pharmacologic therapies and behavioral counseling into the treatment plan for patients with peripheral arterial disease. The role of a smoking cessation specialist enables the vascular nurse to assist patients in successfully overcoming these factors and maintaining abstinence.

Carotid recurrent stenosis and risk of ipsilateral stroke: a systematic review of the literature

BACKGROUND

The main goal of follow-up after carotid endarterectomy is to prevent new strokes caused by recurrent stenosis. To determine the most cost-effective follow-up schedule, it is necessary to know the incidence of recurrent stenosis and the risk of stroke it carries.

METHODS

A systematic review of the literature was performed using standard meta-analytical techniques.

RESULTS

Incidence of recurrent stenosis: The data were very heterogeneous. The risk of recurrent stenosis was 10% in the first year, 3% in the second, and 2% in the third. Long-term risk of recurrent stenosis is about 1% per year. Risk of stroke: The reported relative risks of stroke in patients with recurrent stenosis compared with patients without recurrent stenosis showed extreme heterogeneity and ranged from 10 to 0.10. The random effects summary estimator of relative risk was 1.88.

CONCLUSIONS

The data were very heterogeneous, and much better data are needed to arrive at truly reliable estimates of these important parameters of follow-up. It is clear, though, that the risk of recurrent stenosis is highest in the first few years after carotid endarterectomy and very low in later years. By use of general decision-analytic arguments, it can be argued that, given the test characteristics of carotid ultrasound, a small number of tests can be done in the first few years and that testing for restenosis should not be done after 4 years.

Antibodies to cardiolipin may increase the risk of failure of peripheral vein bypasses

OBJECTIVES

To assess the association between antibodies to cardiolipin and infrainguinal vein graft patency.

MATERIALS AND METHODS

Plasma levels of antibodies to cardiolipin, haemostatic factors, lipids and the smoking marker carboxyhaemoglobin were determined preoperatively and 6 weeks postoperatively in 80 patients undergoing infrainguinal vein bypass surgery. Bypass patency was assessed by ankle blood pressure measurements and ultrasound duplex scanning at 1 week, 6 weeks, 3, 6, 9 and 12 months. A localised increase in the graft peak systolic velocity by a factor of 2.5 or more was considered to indicate a significant stenosis.

RESULTS

Antibodies to cardiolipin were identified in seven (9%) patients preoperatively. In four of these seven patients the bypasses thrombosed within 3 months after surgery and another two developed stenoses. At 6 months the primary bypass patency, i.e. patency without stenosis, was 14% (95% confidence interval (CI) 0-33%) in patients with antibodies to cardiolipin, as opposed to 57% (95% CI 45-69%) in patients without these antibodies (log rank test: p = 0.03). Diabetes mellitus was also associated with a reduced 6 months primary bypass patency (38% (95% CI 16-60%) vs. 58% (95% CI 45-71%), p = 0.006). A Cox regression analysis showed that both the presence of antibodies to cardiolipin and diabetes independently contributed towards predicting the overall risk of bypass failure.

CONCLUSION

Antibodies to cardiolipin were identified in 9% of patients undergoing infrainguinal vein bypass surgery and appeared to be associated with increased risk of bypass failure.

Cigarette smoking increases endothelial-derived vasorelaxation in the rat carotid artery in a dose-dependent manner

While there is clear-cut epidemiologic, morphologic, and functional evidence to suggest that cigarette smoking is deleterious to the cardiovascular system and endothelium, previous experiments with regard to the effect of cigarette smoking on endothelial-derived vasorelaxation are not conclusive. This study examines the effect of cigarette smoking on endothelium-derived vasorelaxation and its relationship to serum nitric oxide concentrations. Fourteen Sprague-Dawley rats (350-500 g) were divided into two groups (N = 7). The experimental group was exposed to six cigarettes (Kentucky 1R4F) per day for 50 days using a Griffith snout exposure method. The two groups were sacrificed and the carotid arteries were mounted on isometric force transducers in a physiologic bath. The arteries were constricted with norepinephrine (1 x 10(-4) M). Vasorelaxation to acetylcholine (Ach) was measured in a dose response manner. Vasorelaxation to nitroglycerin was measured at 10(-4) M. After the rats were sacrificed, blood samples from each rat were examined for total nitrate/nitrite concentration with serum chemiluminescence on a vanadium column. The results were analyzed with ANOVA and the Student's t test. Vasorelaxation to nitroglycerin was 17.42% +/- 0. 44 versus 16.25% +/- 0.42 in the control and smoke exposure groups, respectively (P = 0.19). This experiment counterintuitively demonstrates that cigarette smoking augments endothelial-derived vasorelaxation. No effect was noted in the endothelium-independent vasorelaxation to nitroglycerin. Alternative mechanisms including the presence of hypoxia and exogenous nitric oxide, which lead to endothelial-dependent and -independent vasorelaxation secondary to cigarette smoking, may serve to explain the apparent augmentation of endothelial-derived vasorelaxation. Further experiments with isolated components of smoke will need to be done to resolve the debate.

Factors contributing to recurrent carotid disease following carotid endarterectomy

BACKGROUND

Retrospective analysis was performed to assess the effect of gender, age, hypertension, diabetes, and smoking upon residual disease, recurrent disease, and progression of disease following carotid endarterectomy (CE). The effect of patch versus primary closure was also studied.

METHODS

Postoperative duplex studies were performed following 323 CEs at months 1, 6, 12, and 24. Residual disease was defined as luminal stenosis >59% at 1 month. Progression of disease was defined as stenosis at any month that was greater than stenosis at month 1. Recurrent disease was nonresidual stenosis >79%.

RESULTS

Correlation was found between age at operation <65 years and cigarette smoking; both also correlated with progression of disease on serial studies, as well as recurrent stenosis <79%. Primary closure of the arteriotomy correlated with residual disease.

CONCLUSION

Primary closure of the arteriotomy following CE increases the likelihood of residual disease. Smokers and those aged <65 years are predisposed to progression of postoperative disease, and to development of recurrent stenosis.

Duplex imaging findings predict stenosis after carotid endarterectomy

PURPOSE

This study was performed to determine whether early duplex findings predicted restenosis after carotid endarterectomy.

METHODS

One hundred ninety-two symptomatic patients who underwent carotid endarterectomy were studied with color duplex imaging at 1 day and 1 week after surgery to identify minor residual disease (causing < 50% stenosis), arterial kinking, and suture stricture, and to measure the external and luminal diameters of the carotid bulb and distal internal carotid artery. Patients were then observed prospectively with duplex surveillance for a median of 24 months to identify > 50% restenosis.

RESULTS

Twenty-five stenoses > 50% of the operated carotid artery (13%) were identified, four at 1 day (residual) and 21 at a median follow-up of 6 months (restenosis). On multiple logistic regression analysis, > 50% restenosis was found to be associated with minor day-1 residual stenosis (p = 0.01) and with small luminal diameter of the distal internal carotid artery (p = 0.03) as measured 1 week after carotid endarterectomy. Life table analysis showed restenosis at 24 months to be more common for patients with below-median than patients with above-median carotid bulb external diameter (18% vs 5%, respectively; p = 0.01).

CONCLUSIONS

Duplex scanning within a week of carotid endarterectomy identifies > 50% residual stenosis, in addition to minor residual 25% to 50% stenosis and small carotid dimensions, which are good predictors of > 50% restenosis at 6 months.

Clinical follow-up rather than duplex surveillance after carotid endarterectomy

PURPOSE

The value of duplex surveillance and the significance of contralateral carotid disease after endarterectomy have been assessed.

METHODS

Three hundred five patients were observed prospectively after carotid endarterectomy for a median time of 36 months (range, 6 to 96 months), with duplex surveillance performed at 1 day; 1 week; 3, 6, 9, and 12 months; and then each year after endarterectomy.

RESULTS

Thirty patients (10%) had ipsilateral symptoms (13 strokes, 17 transient ischemic attacks [TIAs]) at a median time of 6 months (range, 0 to 60 months). Life table analysis demonstrated that ipsilateral stroke was equally common for patients who had > or = 50% restenosis (3% at 36 months) and those who did not (6% at 36 months, p > 0.5). Twenty-three patients (8%) developed symptoms (stroke 5, TIA 14) attributable to the contralateral carotid artery at a median time of 9 months (range, 0 to 36 months) after endarterectomy. By life table analysis, 40% of patients with 70% to 99%, 6% with 50% to 69%, 1% with < 50% contralateral internal carotid stenosis, and 5% with contralateral carotid occlusion at the time of endarterectomy had a contralateral TIA in the 36 months after endarterectomy (p < 0.01). However, contralateral stroke was not significantly more common for patients with severe contralateral internal carotid stenosis demonstrated at the time of endarterectomy (< 50% stenosis, 0%; 50% to 69%, 3%; 70% to 99%, 7%; occlusion, 6% stroke rate at 36 months). Seven of the 32 patients who developed progression of contralateral disease had a TIA, compared with 11 of 227 patients who did not develop progression of contralateral disease (p < 0.01). None of the 12 patients who progressed from a < 70% to a 70% to 99% contralateral stenosis had a stroke.

CONCLUSIONS

After carotid endarterectomy restenosis is rarely associated with symptoms; contralateral stroke is rare and is not associated with progressive internal carotid artery disease suitable for endarterectomy. This study has shown no benefit from long-term duplex surveillance after carotid endarterectomy. Selective clinical follow-up of patients who have high-grade contralateral stenoses would appear more appropriate.

Nicotine and cotinine stimulate secretion of basic fibroblast growth factor and affect expression of matrix metalloproteinases in cultured human smooth muscle cells

PURPOSE

We have recently shown that nicotine and its metabolite cotinine are mitogenic for smooth muscle cells in vitro. In the present study, we examined the effect of nicotine and cotinine on the production of growth factors and the expression of matrix metallo-proteinases in smooth muscle cells.

METHODS

Smooth muscle cells were harvested from human arteries and grown in culture. Subconfluent cultures were incubated for 24 hours in M199 containing 0.1% fetal bovine serum with or without nicotine or cotinine at concentrations ranging from 10(-9) mol/L to 10(-6) mol/L. The supernatants and cell lysates were assayed by enzyme-linked immunosorbent assay for basic fibroblast growth factor (bFGF), tumor necrosis factor alpha (TNF-alpha), platelet-derived growth factor AB (PDGF-AB), and transforming growth factor beta (TGF-beta). Matrix metalloproteinase expression was determined in subconfluent cultures incubated in albumin with or without nicotine or cotinine at 10(-8) mol/L and 10(-7) mol/L for 6, 12, 18, 24 and 36 hours. Northern blot analyses were performed with human cDNA probes for collagenase-1, stromelysin-1, gelatinase A, gelatinase B, and triose phosphate isomerase. Blots were quantified by phosphor-imaging techniques.

RESULTS

Both nicotine and cotinine stimulated the production and secretion of bFGF in a dose-dependent manner. PDGF, TNF-alpha, and TGF-beta secretions were not significantly affected by nicotine or cotinine. Collagenase was up-regulated by nicotine at 18 and 24 hours (4.5-fold to 5.8-fold) and by cotinine at 18 hours (from 5.0-fold to 29-fold). Stromelysin-1 was up-regulated by nicotine and cotinine at 12 and 18 hours (1.5-fold to 7.0-fold). Gelatinase A generally peaked at 12 hours and was up-regulated by both agents (2.0-fold to 6.5-fold).

CONCLUSION

Nicotine and cotinine enhanced the production of bFGF, a major mitogen for smooth muscle cells, and up-regulated the expression of several matrix metalloproteinases that are critical in cell migration. These data demonstrate mechanisms by which smoking may contribute to the development of intimal hyperplasia, atherosclerosis, and aneurysms.

Late outcome of patients with premature carotid atherosclerosis after carotid endarterectomy

BACKGROUND AND PURPOSE

The durability of carotid endarterectomy (CEA) in young adults with premature carotid atherosclerosis has not been adequately assessed. This study examined the late recurrence and mortality rates in young adults undergoing CEA.

METHODS

We studied 42 young patients (mean age, 45.5 +/- 0.5 years) who underwent CEA and compared them with 110 older control subjects (mean age, 65.8 +/- 0.4 years) undergoing CEA during the same period. Data were collected regarding demographics, operative indications, follow-up carotid duplex studies, recurrent symptoms, and deaths.

RESULTS

Demographics and atherosclerotic risk factors were similar between the two groups. During a mean follow-up of 57.9 +/- 6.0 months, 10 (24%) young patients and 3 (3%) control subjects developed significant, recurrent ipsilateral stenoses (> or = 50% diameter loss) (P < .001). Six (14%) young patients and 1 control subject had recurrent ipsilateral symptoms (P = .002). Nine (21%) young patients and 26 (24%) older control subjects required contralateral CEA; 8 (18%) young patients and 18 (16%) older control subjects underwent lower extremity revascularization procedures. Cumulative 5-year survival by life-table analysis was 0.83 (95% confidence interval [CI], 0.71 to 0.95) for study patients and was 0.67 (95% CI, 0.58 to 0.77) for control subjects (P = .06).

CONCLUSIONS

These data demonstrate a trend toward more favorable survival in young versus older patients after CEA; however, survival differences did not achieve statistical significance. Young patients are far more likely to develop recurrent symptoms and recurrent carotid stenoses than older counterparts. Close follow-up with serial duplex ultrasound may be important in young patients after CEA.

Outcome of selective patching following carotid endarterectomy

OBJECTIVES

Routine patch angioplasty has been advocated following carotid endarterectomy but patching can be associated with complications. This study assesses the effect of a selective patching policy based on distal internal carotid diameter on the rate of restenosis and outcome following carotid endarterectomy.

DESIGN, MATERIAL AND METHODS

A consecutive series of 213 patients underwent carotid endarterectomy performed by one surgeon. Preoperative carotid dimensions were measured intraoperatively using calipers. Following endarterectomy a 5mm Dacron patch was selectively employed if the distal internal carotid was 5mm or less (group 1, 95 patients) or 6mm or less (group 2, 118 patients). Patients underwent colour-coded Duplex scanning at 24 h, 1 week, 3, 6, 9, and 12 months, and yearly following this.

RESULTS

Overall 27 restenoses (5 residual) of 50% or greater and two occlusions developed. Patching was performed in 47% of group 1 and 61% of group 2 arteries. In group 1 14% of patched compared with 24% of non-patched arteries developed restenosis at 24 months (p=0.4). In group 2 13% of patched compared to 11% of non-patched arteries developed restenosis at 12 months (p>0.5). Stroke rate at 24 months were similar for patched and non-patched patients in groups 1 (p>0.5) and 2 (p=0.4).

CONCLUSIONS

This study suggests that patch angioplasty of larger carotid arteries may be unnecessary. Randomisation of larger arteries between patch and primary closure would be required to confirm this.

Carotid artery surgery in the octogenarian

BACKGROUND

The value of carotid surgery is largely dependent on the safety of the procedure. With changes in population life expectancy, increasing numbers of elderly patients are being considered for surgery.

METHODS

In the present paper, the results of 113 patients (octogenarians: > 80 years of age) who underwent carotid endarterectomy in the 17 years prior to 1994 are reported. This group composed 6.2% of the 1818 patients treated in the period, 665 (36.6%) operations were performed on patients 50-65 years inclusive and 1040 (57.2%) on patients aged 66-80 years inclusive.

RESULTS

The overall peri-operative stroke rate was 2.5% and the postoperative mortality was 1.9% with no statistical difference apparent between the age groups despite hemispheric strokes being the most common indication for operation in the octogenarian group (29.5%) and the least common indication in the youngest age group (16.2%, P <0.01). Long-term follow up (2-7 years) of octogenarian patients undergoing carotid surgery suggested maintenance of pre-operative levels of living independence.

CONCLUSIONS

The results of the study indicated that octogenarian patients should not be denied carotid endarterectomy on the basis of age alone and that results comparable to those of younger patients can be anticipated.

Cigarette smoking increases the development of initial hyperplasia after vascular injury

PURPOSE

Our purpose was to determine whether exposure to cigarette smoke increases the development of intimal hyperplasia (IH) after vascular injury.

METHODS

Sixteen adult male Sprague-Dawley rats underwent standardized balloon catheter injury of the left common carotid artery. For 4 weeks before and 4 weeks after injury, animals in the experimental group (n=8) were exposed to cigarette smoke with an automated vacuum pump device. Animals in the control group (n=8) were restrained in the smoking device for an identical amount of time and underwent arterial injury at 4 vivo, prepared as histologic cross sections, and stained for elastin. IH was measured by planimetry and is reported both as the absolute area of IH and as the ratio (IH/IEL) of the absolute area of IH to the normalized area enclosed by the internal elastic lamina (expressed as a percent).

RESULTS

The absolute area of IH was 2.09 +/- 0.34 for the experimental group compared with 0.94 +/- 0.25 for the control group; mean IH/IEL was 43% +/- 7.1% for the experimental group versus 17.7% +/- 4.7% for the control group (p < 0.05, two tailed unpaired t test.

CONCLUSIONS

Inhalation of cigarette smoke increases the development of intimal hyperplasia in a rat model of a balloon catheter arterial injury.

The influence of fibrinogen concentration on the development of vein graft stenoses

OBJECTIVE

The aim of this study was to identify factors associated with the development of graft stenoses in the first year after bypass.

DESIGN AND SETTING

Between January 1992 and April 1993, 75 consecutive patients undergoing distal vein bypass surgery were entered into a graft surveillance programme at Charing Cross Hospital. The grafts (n = 79) were surveyed by colour flow Doppler ultrasonography at 7 days, 3, 6, 9 and 12 months and the site of stenoses (> 50%) recorded. Position of the distal anastomosis, graft type (in situ or reverse) and clinical history were recorded. At the 3-month surveillance a blood sample was taken for the estimation of smoking markers, lipids and fibrinogen.

RESULTS

The site of the distal anastomosis was to the suprageniculate popliteal in nine, infrageniculate popliteal in 32 and tibio/peroneal vessels in 38 cases. In the first month following bypass there were six deaths, giving a 30 day mortality of 7.5%, three patients were lost to follow up, seven grafts occluded, three were replaced by PTFE, four patients underwent amputation and one patient had a redo vein graft. In the remaining grafts 20/63 (32%) developed stenoses within the first year after bypass. The development of a graft stenosis was not associated with sex, diabetic status, site of distal anastomosis, graft type or serum lipids. Multiple regression analysis identified only one factor associated significantly with the development of vein graft stenosis: fibrinogen concentration (p = 0.003). Life table analysis showed that after 1 year only 46% of grafts remained free of stenoses in patients with above median fibrinogen concentrations compared with 84% of grafts in patients with below median fibrinogen concentrations, p = 0.009.

CONCLUSIONS

Increased plasma fibrinogen concentration is a potent risk factor for the development of vein graft stenosis. These results prompt consideration of the role of fibrinogen in stimulating smooth muscle cell proliferation in the stenotic lesion.