Systematic review of the risks of carotid endarterectomy in relation to the clinical indication for and timing of surgery.

BACKGROUND AND PURPOSE: Reliable data on the risk of carotid endarterectomy (CEA) in relation to clinical indication and timing of surgery are necessary to target CEA more effectively, to inform patients, to adjust risks for case mix, and to understand the mechanisms of operative stroke. METHODS: We performed a systematic review of all studies published from 1980 to 2000 inclusive that reported the risk of stroke and death resulting from CEA. Pooled estimates of risk by type of presenting ischemic event and time since the last event were obtained by Mantel-Haenszel meta-analysis. RESULTS: Of 383 published studies, only 103 stratified risk by indication. Although the operative risk for symptomatic stenosis overall was higher than for asymptomatic stenosis (odds ratio [OR], 1.62; 95% confidence interval [CI], 1.45 to 1.81; P<0.00001; 59 studies), risk in patients with ocular events only tended to be lower than for asymptomatic stenosis (OR, 0.75, 95% CI, 0.50 to 1.14; 15 studies). Operative risk was the same for stroke and cerebral transient ischemic attack (OR, 1.16; 95% CI, 0.99 to 1.35; P=0.08; 23 studies) but higher for cerebral transient ischemic attack than for ocular events only (OR, 2.31; 95% CI, 1.72 to 3.12; P<0.00001; 19 studies) and for CEA for restenosis than primary surgery (OR, 1.95; 95% CI, 1.21 to 3.16; P=0.018; 6 studies). Urgent CEA for evolving symptoms had a much higher risk (19.2%, 95% CI, 10.7 to 27.8) than CEA for stable symptoms (OR, 3.9; 95% CI, 2.7 to 5.7; P<0.001; 13 studies), but there was no difference between early (<3 to 6 weeks) and late (>3 to 6 weeks) CEA for stroke in stable patients (OR, 1.13; 95% CI, 0.79 to 1.62; P=0.62; 11 studies). All observations were highly consistent across studies. CONCLUSIONS: Risk of stroke and death resulting from CEA is highly dependent on the clinical indication. Audits of risk should be stratified accordingly, and patients should be informed of the risk that relates to their presenting event

Routine or selective carotid artery shunting for carotid endarterectomy (and different methods of monitoring in selective shunting).

BACKGROUND: Temporary interruption of cerebral blood flow during carotid endarterectomy can be avoided by using a shunt across the clamped section of the carotid artery. This may improve outcome. OBJECTIVES: The objective of this review was to assess the effect of routine versus selective, or never, shunting during carotid endarterectomy, and to assess the best method for selecting patients for shunting. SEARCH STRATEGY: For the original review the authors searched the Cochrane Stroke Group trials register, Medline (1966 to 1994), Embase (1980 to 1995) and Index to Scientific and Technical Proceedings (1980 to 1994). They also hand searched Annals of Surgery (1981 to 1995), British Journal of Surgery (1985 to 1995), European Journal of Vascular Surgery (1988 to 1995) and World Journal of Surgery (1978 to 1995). For the updated review, for the dates January 1994 - December 2000 we: 1. Repeated all these searches performed for the original review and developed more comprehensive search strategies for Medline and Embase. The Cochrane Stroke Group Trials Register was last searched in May 2001. 2. Hand searched the Journal of Vascular Surgery, Stroke, Annals of Vascular Surgery, American Journal of Surgery and Cardiovascular Surgery. 3. Hand searched the abstracts from the International Stroke Conference, AGM of the Vascular Surgical Society (UK), AGM of the Association of Surgeons of Great Britain and Ireland and the Annual Meeting of the Society for Vascular Surgery (USA). 4. Searched reference lists from all relevant trials All the authors of studies included in the initial review, and other authors known to have published relevant work, were contacted requesting information about further published or unpublished data. SELECTION CRITERIA: Randomised and quasi-randomised trials of routine shunting compared with no shunting or selective shunting, and trials that compared different shunting policies in patients undergoing carotid endarterectomy. DATA COLLECTION AND ANALYSIS: For the original review two reviewers independently performed the searches and applied the inclusion criteria. The data were extracted by one reviewer and double-checked. Trial quality was assessed. During the update, two reviewers independently performed the searches and applied the inclusion criteria. No new relevant randomised controlled trials were found. MAIN RESULTS: Despite recommendation from the original review that further studies were required, no new trials of adequate quality and fitting the inclusion criteria were found. The initial review included three trials. Two trials involving 590 patients compared routine shunting with no shunting. The other trial involving 131 patients compared shunting with a combination of electroencephalographic and carotid pressure measurement, with shunting by carotid pressure measurement alone. Allocation was adequately concealed in one trial, and one trial was quasi-randomised. Analysis was by intention-to-treat where possible. For routine versus no shunting, there was no significant difference in the rate of all stroke, ipsilateral stroke or death up to 30 days after surgery, although data were limited. There was no significant difference between the risk of ipsilateral stroke in patients selected for shunting with the combination of electroencephalographic and carotid pressure assessment compared to pressure assessment alone, although again the data were limited. REVIEWER'S CONCLUSIONS: When first published in 1995, this review concluded that the data available were too limited to either support or refute the use of routine or selective shunting in carotid endarterectomy. It was suggested that large scale randomised trials using no shunting as the control group were required. No one method of monitoring in selective shunting has been shown to produce better outcomes. No further prospective randomised or quasi-randomised trials have been performed since then and the conclusions therefore remain unchanged

Patches of different types for carotid patch angioplasty.

BACKGROUND: Some surgeons who use carotid patching favour using a patch made from an autologous vein, whilst others prefer to use synthetic materials. OBJECTIVES: The objective of this review was to assess the safety and efficacy of different materials for carotid patch angioplasty. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register (last searched November 2002). In addition, we searched the Cochrane Controlled Trials Register (The Cochrane Library, Issue 4, 2001), MEDLINE (1966 to December 2001), EMBASE (1980 to December 2001) and Index to Scientific and Technical Proceedings (1980 to 2001). We also handsearched eight journals and five conference proceedings. Reference lists were checked and we contacted experts in the field to identify further published and unpublished studies. SELECTION CRITERIA: Randomised and quasi-randomised trials comparing one type of carotid patch with another for carotid endarterectomy. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed eligibility, trial quality, and extracted the data MAIN RESULTS: The previous version of this review included three trials involving 326 operations. Since then a further five trials have been reported, increasing the number of operations to 1480. Prior to 1995, all studies had compared vein closure with PTFE closure, but three of the later studies compared vein to Dacron grafts instead and one compared Dacron with PTFE. Allocation was not adequately concealed in two trials, and one only followed up patients to the time of hospital discharge. Intention to treat analysis was possible for six trials. In all but two trials a patient could be randomised twice and have each carotid artery randomised to different treatment groups. There were too few operative events to determine whether there was any difference between the vein and Dacron patches for perioperative stroke, death and arterial complications. The one study that compared Dacron and PTFE patches found a significant risk of combined stroke and transient ischaemic attack (p = 0.03) and restenosis at 30 days (p = 0.01), a borderline significant risk of perioperative stroke (p = 0.06), and a non significant increased risk of perioperative carotid thrombosis (p = 0.1) with dacron compared with PTFE. Five trials followed up patients for longer than 30 days. During follow-up for more than one year, no difference was shown between the two types of patch for the risk of stroke, death, or arterial restenosis. However, the number of events was small. Based on 15 events in 776 patients in four trials, there were significantly fewer pseudoaneurysms associated with synthetic patches than vein (odds ratio [OR] 0.09, 95% confidence interval [CI] 0.02 to 0.49) but the numbers involved were small and the clinical significance of this finding is uncertain. REVIEWERS' CONCLUSIONS: It is likely that the differences between different types of patch material are very small. Consequently, many more data than are currently available will be required to establish whether any differences do exist. Some evidence exists that PTFE patches may be superior to Colagen impregnated Dacron grafts in terms of perioperative stroke rates and restenosis. However the evidence is based upon data from a single, small trial and more studies that compare different types of synthetic graft are required to make firm conclusions. Psuedo aneurysm formation may be more common after use of a vein patch compared with a synthetic patch

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

Systematic review of randomized controlled trials of patch angioplasty versus primary closure and different types of patch materials during carotid endarterectomy.

BACKGROUND: Patch angioplasty during carotid endarterectomy (CEA) may reduce the risk for perioperative or late carotid artery recurrent stenosis and subsequent ischemic stroke. We performed a systematic review of randomized controlled trials to assess the effect of routine or selective carotid patch angioplasty compared with CEA with primary closure, and the effect of different materials used for carotid patch angioplasty. METHODS: Randomized trials were included if they compared carotid patch angioplasty with primary closure in any patients undergoing CEA or use of one type of carotid patch with another. RESULTS: Thirteen eligible randomized trials were identified. Seven trials involving 1281 operations compared primary closure with routine patch closure, and 8 trials with 1480 operations compared different patch materials (2 studies compared both). Patch angioplasty was associated with a reduction in risk for stroke of any type (P = .004), ipsilateral stroke (P = .001), and stroke or death during both the perioperative period (P = .007) and long-term follow-up (P = .004). Patching was also associated with reduced risk for perioperative arterial occlusion (P = .0001) and decreased recurrent stenosis during long-term follow-up (P < .0001). Seven trials that compared different patch types showed no difference in the risk for stroke, death, or arterial recurrent stenosis either perioperatively or at 1-year follow-up. One study of 180 patients (200 arteries) compared collagen-impregnated Dacron (Hemashield) patches with polytetrafluoroethylene patches. There was a significant increase in risk for stroke (P = .02), combined stroke and transient ischemic attack (P = .03), and recurrent stenosis (P = .01) at 30 days, and an increased risk for late recurrent stenosis greater than 50% (P < .001) associated with Dacron compared with polytetrafluoroethylene. CONCLUSIONS: Carotid patch angioplasty decreases the risk for perioperative death or stroke, and long-term risk for ipsilateral ischemic stroke. More data are required to establish differences between various patch materials

Routine or selective carotid artery shunting for carotid endarterectomy (and different methods of monitoring in selective shunting).

BACKGROUND: Temporary interruption of cerebral blood flow during carotid endarterectomy can be avoided by using a shunt across the clamped section of the carotid artery. This may improve outcome. OBJECTIVES: The objective of this review was to assess the effect of routine versus selective, or never, shunting during carotid endarterectomy, and to assess the best method for selecting patients for shunting. SEARCH STRATEGY: For the original review the authors searched the Cochrane Stroke Group trials register, Medline (1966 to 1994), Embase (1980 to 1995) and Index to Scientific and Technical Proceedings (1980 to 1994). They also hand searched Annals of Surgery (1981 to 1995), British Journal of Surgery (1985 to 1995), European Journal of Vascular Surgery (1988 to 1995) and World Journal of Surgery (1978 to 1995). For the updated review, for the dates January 1994 - December 2000 we: 1. Repeated all these searches performed for the original review and developed more comprehensive search strategies for Medline and Embase. The Cochrane Stroke Group Trials Register was last searched in May 2001. 2. Hand searched the Journal of Vascular Surgery, Stroke, Annals of Vascular Surgery, American Journal of Surgery and Cardiovascular Surgery. 3. Hand searched the abstracts from the International Stroke Conference, AGM of the Vascular Surgical Society (UK), AGM of the Association of Surgeons of Great Britain and Ireland and the Annual Meeting of the Society for Vascular Surgery (USA). 4. Searched reference lists from all relevant trials All the authors of studies included in the initial review, and other authors known to have published relevant work, were contacted requesting information about further published or unpublished data. SELECTION CRITERIA: Randomised and quasi-randomised trials of routine shunting compared with no shunting or selective shunting, and trials that compared different shunting policies in patients undergoing carotid endarterectomy. DATA COLLECTION AND ANALYSIS: For the original review two reviewers independently performed the searches and applied the inclusion criteria. The data were extracted by one reviewer and double-checked. Trial quality was assessed. During the update, two reviewers independently performed the searches and applied the inclusion criteria. No new relevant randomised controlled trials were found. MAIN RESULTS: Despite recommendation from the original review that further studies were required, no new trials of adequate quality and fitting the inclusion criteria were found. The initial review included three trials. Two trials involving 590 patients compared routine shunting with no shunting. The other trial involving 131 patients compared shunting with a combination of electroencephalographic and carotid pressure measurement, with shunting by carotid pressure measurement alone. Allocation was adequately concealed in one trial, and one trial was quasi-randomised. Analysis was by intention-to-treat where possible. For routine versus no shunting, there was no significant difference in the rate of all stroke, ipsilateral stroke or death up to 30 days after surgery, although data were limited. There was no significant difference between the risk of ipsilateral stroke in patients selected for shunting with the combination of electroencephalographic and carotid pressure assessment compared to pressure assessment alone, although again the data were limited. REVIEWER'S CONCLUSIONS: When first published in 1995, this review concluded that the data available were too limited to either support or refute the use of routine or selective shunting in carotid endarterectomy. It was suggested that large scale randomised trials using no shunting as the control group were required. No one method of monitoring in selective shunting has been shown to produce better outcomes. No further prospective randomised or quasi-randomised trials have been performed since then and the conclusions therefore remain unchanged