BACKGROUND Carotid patch angioplasty (with either a venous or a synthetic patch) may reduce the risk of carotid artery restenosis and subsequent ischaemic stroke. OBJECTIVE The objective of this review was to assess the safety and efficacy of routine or selective carotid patch angioplasty compared to carotid endarterectomy with primary closure. METHODS 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 Reference lists were checked and we contacted experts in the field to identify further published and unpublished studies. METHODS Randomised and quasi-randomised trials comparing carotid patch angioplasty with primary closure in any patients undergoing carotid endarterectomy. METHODS Two reviewers independently assessed eligibility, trial quality and extracted the data. RESULTS The previous review included six trials involving 794 patients undergoing 882 operations. Since the last review only one study of adequate quality to be included has been reported. This added 399 operations randomised to either primary closure, vein patch or synthetic patch groups resulting in 1127 patients undergoing 1307 operations being available for analysis. The quality of trials was generally poor. Follow-up varied from hospital discharge to five years. Carotid patch angioplasty was associated with a reduction in the risk of stroke of any type (OR = 0.33, p = 0.004), ipsilateral stroke (OR = 0.31, p = 0.0008), and stroke or death, during the perioperative period (OR = 0.39, p = 0.007) and long term follow-up (OR = 0.59, p = 0.004). It was also associated with a reduced risk of perioperative arterial occlusion (odds ratio 0.15, 95% confidence interval 0.06 to 0.37 p = 0.00004), and decreased restenosis during long-term follow-up in five trials, (odds ratio 0.20, 95% confidence interval 0.13 to 0.29 p < 0.00001). These results are more certain than those of the previous review since the number of operations and events have increased. However, the sample sizes are still relatively small, data were not available from all trials, and there was significant loss to follow-up. Very few arterial complications, including haemorrhage, infection, cranial nerve palsies and pseudo-aneurysm formation were recorded with either patch or primary closure. No significant correlation was found between use of patch angioplasty and the risk of either perioperative or long-term all-cause death rates CONCLUSIONS Limited evidence suggests that carotid patch angioplasty may reduce the risk of perioperative arterial occlusion and restenosis. It would appear to reduce the risk of combined death or stroke and there is a non significant trend towards a reduction in all-cause mortality.