Internal carotid artery surgery: ten-year results

Meta- analysis and meta-regression analysis of the associations between sex and the operative outcomes of carotid endarterectomy

Background

Subgroup analyses from randomized controlled trials (RCT) of carotid endarterectomy (CEA) for both symptomatic and asymptomatic carotid stenosis suggest less benefit in women compared to men, due partly to higher age-independent peri-operative risk. However, a meta-analysis of case series and databases focussing on CEA-related gender differences has never been investigated.

Methods

A systematic review of all available publications (including case series, databases and RCTs) reporting data on the association between sex and procedural risk of stroke and/or death following CEA from 1980 to 2015 was investigated. Pooled Peto odds ratios of the procedural risk of stroke and/or death were obtained by Mantel-Haenszel random-effects meta-analysis. The I² statistic was used as a measure of heterogeneity. Potential publication bias was assessed with the Egger test and represented graphically with Begg funnel plots of the natural log of the OR versus its standard error. Additional sensitivity analyses were undertaken to evaluate the potential effect of key assumptions and study-level factors on the overall results. Meta-regression models were formed to explore potential heterogeneity as a result of potential risk factors or confounders on outcomes. A tria sequential analysis (TSA) was performed with the aim to maintain an over- all 5 % risk of type I error, being the standard in most meta- analyses and systematic reviews.

Results

58 articles reported combined stroke and mortality rates within 30 days of treatment. In the unselected overall meta-analysis, the incidence of stroke and death in the male and female groups differed significantly (Peto OR, 1,162; 95 % CI, 1.067-1.266; P = .001), revealing a worse outcome for female patients. Moderate heterogeneity among the studies was identified (I² = 36 %), and the possibility of publication bias was low (P = .03). In sensitivity analyses the meta-analysis of case series with gender aspects as a secondary outcome showed a significantly increased risk for 30-day stroke and death in women compared to men (Peto OR, 1.390; 95 % CI, 1.148-1.684; P = .001), In contrast, meta-analysis of databases (Peto OR, 1.025; 95 % CI, 0.958-1.097; P = .474) and case series with gender related outcomes as a primary aim (Peto OR, 1.202; 95 % CI, 0.925-1.561; P = .168) demonstrated no increase in operative risk of stroke and death in women compared to men.

Conclusions

Metanalyses of case series and databases dealing with CEA reveal inconsistent results regarding gender differences related to CEA-procedure and should not be transferred into clinical practice.

An audit of carotid endarterectomy for internal carotid artery disease at Dunedin Hospital

Carotid endarterectomy, mostly for symptomatic internal carotid artery stenosis, has been successfully performed in both the vascular and neurological surgery units at Dunedin Hospital. This study was performed to compare our results with those of the North American Symptomatic Carotid Endarterectomy Trial and the European Carotid Surgery Trial. The 30-day perioperative morbidity and mortality rate was 4.3% (1.2% < 95% Cl > 7.4%) which compares favourably with an estimated upper limit of 5.5% based on recent trial reports. The present study highlights the difficulty in modelling local clinical practice on results of major trials when standards of patient evaluation and surgical skill may differ from those of the large studies. To justify generalization of indications for intervention based on the multicentre trials, there must be continual monitoring of local surgical results, and standardized use of diagnostic investigations.

A Systematic Review of the Associations between Age and Sex and the Operative Risks of Carotid Endarterectomy

BACKGROUND

Randomized trials of carotid endarterectomy (CEA) for both symptomatic and asymptomatic carotid stenosis have demonstrated that benefit is decreased in women, due partly to a high operative risk, which is independent of age. However, it is uncertain whether these trial-based observations are generalisable to routine clinical practice.

METHODS

We performed a systematic review of all publications reporting data on the association between age and/or sex and procedural risk of stroke and/or death following CEA from 1980 to 2004.

RESULTS

62 eligible papers reported relevant data. Females had a higher rate of operative stroke and death (25 studies, OR = 1.31, 95% CI = 1.17-1.47, p < 0.001) than males, but no increase in operative mortality (15 studies, OR = 1.05, 95% CI = 0.81-0.86, p = 0.78). Compared with younger patients, operative mortality was increased at > or =75 years (20 studies, OR = 1.36, 95% CI = 1.07-1.68, p = 0.02), at age > or =80 years (15 studies, OR = 1.80, 95% CI = 1.26-2.45, p < 0.001) and in older patients overall (35 studies, OR = 1.50, 95% CI = 1.26-1.78, p < 0.001). In contrast, risk of non-fatal stroke did not increase with age and so the combined perioperative risk was only slightly increased at age > or =75 years (21 studies, OR = 1.18, 95% CI = 0.94-1.44, p = 0.06), at age > or =80 years (10 studies, OR = 1.14, 95% CI = 0.92-1.36, p = 0.34) and in older patients overall (36 studies, OR = 1.17, 95% CI = 1.04-1.31, p = 0.01).

CONCLUSIONS

The effects of age and sex on the operative risk of CEA in published case series are consistent with those observed in the trials. Operative risk of stroke is increased in women and operative mortality is increased in patients aged > or =75 years.

Surgery for asymptomatic carotid stenosis: a study of three patient subgroups

The purpose of this retrospective study was to determine whether patients who undergo prophylactic surgery for asymptomatic carotid stenosis represent a single homogeneous population. Of the 805 carotid reconstructions performed between January 1984 and December 1992, a total of 357 were for asymptomatic atherosclerotic stenosis in 312 patients (227 men, 85 women) with a mean age of 69.6 years. Patients were divided into three groups. Group I included 141 patients (161 procedures) who presented no neurologic manifestations. Group II included 49 patients (55 procedures) who underwent carotid reconstruction before or at the same time as another cardiovascular procedure. Group III included 122 patients (141 procedures) who presented nonhemispheric manifestations. Patients in group III had a significantly higher number of obstructive lesions in brain arteries (p < 0.01). Seven patients died within the first 30 postoperative days, including three who underwent combined single-stage procedures. Nine patients presented nonfatal stroke, including three who progressively recovered. The cumulative death-stroke rate (CDSR) was 5.12% overall, 3.54% in group I, 12.24% in group II, and 4.09% in group III. The difference between groups I and II was statistically significant (p < 0.05). Taking into account only deaths related to carotid surgery and stroke with permanent disability, the CDSR was 2. 83% in group I and 3.25% in group III. Follow-up ranged from 24 to 132 months (mean: 66.2) with a total of 11 patients being lost from follow-up. Actuarial 5-year survival was 81.99 +/- 7.13% in group I, 70.65 +/- 13.72% in group II, and 68.51 +/- 8.93% in group III. Differences between group I and both groups II (p < 0.01) and III (p < 0.05) were statistically significant. Overall 5-year patency was 95.59 +/- 2.28%. Stroke occurred during follow-up in 13 patients. The probability of stroke-free survival was 95.29 +/- 3.76% in group I, 91.03 +/- 8.52% in group II, and 89.09 +/- 6.39% in group III. The difference between groups I and III was statistically significant (p < 0.05). Patients with asymptomatic carotid lesions can be divided into different prognostic groups. Life expectancy is shorter for patients with multiple artery disease. Long-term stroke risk is higher in patients with nonhemispheric neurological manifestations.

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.

Saphenous vein bypass: an alternative to internal carotid reconstruction

OBJECTIVE

Venous grafting is rarely employed for carotid reconstruction; the aim of this retrospective study was to assess its value as an alternative to endarterectomy.

MATERIAL

Between January 1980 and June 1990, we performed 212 carotid artery venous bypasses (CVB) on 208 patients. Twenty-nine patients were asymptomatic, 60 had non-hemispheric symptoms and 119 focal symptoms. The indication for surgery was stenosis in 185 cases, kinking in 18 and aneurysms in nine. The main criteria to use CVB were length of the lesion in 86 cases, extent of atherosclerosis in 75, dysplasia in 12, intraoperative failure of endarterectomy in 21, aneurysms in seven and long-term restenosis or occlusion in 12.

RESULTS

There were 11 deaths, three strokes and nine transient ischaemic attacks. Angiographic control showed one occlusion giving an immediate patency rate of 99.5%. Mean follow-up was 104.3 +/- 46.1 months with 15 patients lost to follow-up. Eighty patients died; life expectancy was 52.4 +/- 7.5 at 10 years. Including occlusions and restenosis as failures, the secondary patency rate was 96.4 +/- 3.7 at 10 years. The annual stroke rate was 1.3% and the neurologic event-free-population 87 +/- 2.4% at 10 years.

CONCLUSION

CVB is a valuable alternative to endarterectomy for reconstruction of the carotid artery. The indications are extensive atherosclerosis involving the common carotid artery, intraoperative anatomic failure of endarterectomy, and long-term restenosis.