Patches of different types for carotid patch angioplasty

Some surgeons who use carotid patching favour using a patch made from an autologous vein, whilst others prefer to use synthetic materials.

The objective of this review was to assess the safety and efficacy of different materials for carotid patch angioplasty.

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 Reference lists were checked and we contacted experts in the field to identify further published and unpublished studies.

Randomised and quasi-randomised trials comparing one type of carotid patch with another for carotid endarterectomy.

Two reviewers independently assessed eligibility, trial quality, and extracted the data

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.

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.