Patches of different types for carotid patch angioplasty

Question

What are the best types of patch materials for patients who undergo carotid patch angioplasty?

Background
Carotid endarterectomy is an operation done to remove some diseased artery lining that has caused a stroke. Usually patients who need this operation are at risk of a stroke because of recent stroke symptoms or severe disease of the carotid artery. Inserting a patch at the end of the carotid operation appears to reduce the risk of further stroke and artery disease. These patches are made of synthetic material, the patient’s own vein, or other natural materials such as bovine pericardium. Vein patching is often used and is resistant to infection. However, abnormal swelling of the patch or patch rupture has been a matter of concern. Synthetic patch materials including Dacron and polytetrafluoroethylene (PTFE) have high strength and may involve lower risk of patch rupture. However, synthetic materials may confer greater risk of infection. Bovine pericardium may carry lower risk for both infection and other complications. However the best choice of material for carotid patch angioplasty procedures is still uncertain. This review aims to assess whether one type of patch is better than another for clinical outcomes (such as stroke and death) and complications (such as patch rupture or infection).

Search date
We searched for studies up to 25 May 2020.

Study characteristics
This review identified 14 randomised controlled trials (RCTs) involving 2278 carotid endarterectomies, which compared different patch materials: seven trials compared vein closure with PTFE closure, five compared Dacron grafts with other synthetic materials, and two compared bovine pericardium with other synthetic materials. Primary endpoints were postoperative and long-term (during at least one year) stroke on the operated side. Secondary endpoints were any stroke, transient ischaemic attack (TIA), death, artery narrowing or blockage, and other complications including artery rupture, cranial nerve palsy, wound infection or bleeding, and reoperation or abnormal swelling (pseudoaneurysm).

Key results
The results of using different types of patch materials after carotid endarterectomy were as follows.
• Vein patch versus synthetic material: there were no differences in the risk of stroke postoperatively or over the long term. The main concerns were that vein patches appeared to result in more abnormal swelling (pseudoaneurysm). Information on other complications was limited.

• Dacron versus other synthetic material: Dacron patches were associated with higher risk of combined perioperative stroke and TIA, early arterial re-stenosis or occlusion, and any strokes at longer-term follow-up, although numbers of outcome events were small.

• Bovine pericardium patch versus other synthetic materials: there were no differences in any clinical outcomes or complications, although the numbers of outcome events were small. Information on other complications was limited.

Quality of the evidence
Most evidence was of low or very low quality due to research methods and small numbers. No RCTs could be blinded for surgeons or patients due to the nature of the intervention, and most trials did not report their funding source. Most outcomes were downgraded for imprecision due to wide confidence intervals and low event rates.

Authors' conclusions: 

The number of outcome events is too small to allow conclusions, and more trial data are required to establish whether any differences do exist. Nevertheless, there is little to no difference in effect on perioperative and long-term ipsilateral stroke between vein and any synthetic patch material. Some evidence indicates that other synthetic patches (e.g. PTFE) may be superior to Dacron grafts in terms of perioperative stroke and TIA rates, and both early and late arterial re-stenosis and occlusion. Pseudoaneurysm formation may be more common after use of a vein patch than after use of a synthetic patch. Bovine pericardial patch, which is an acellular xenograft material, may reduce the risk of perioperative fatal stroke, death, and infection compared to other synthetic patches. Further large RCTs are required before definitive conclusions can be reached.

Read the full abstract...
Background: 

Extracranial carotid artery stenosis is the major cause of stroke, which can lead to disability and mortality. Carotid endarterectomy (CEA) with carotid patch angioplasty is the most popular technique for reducing the risk of stroke. Patch material may be made from an autologous vein, bovine pericardium, or synthetic material including polytetrafluoroethylene (PTFE), Dacron, polyurethane, and polyester. This is an update of a review that was first published in 1996 and was last updated in 2010.

Objectives: 

To assess the safety and efficacy of different types of patch materials used in carotid patch angioplasty. The primary hypothesis was that a synthetic material was associated with lower risk of patch rupture versus venous patches, but that venous patches were associated with lower risk of perioperative stroke and early or late infection, or both.

Search strategy: 

We searched the Cochrane Stroke Group trials register (last searched 25 May 2020); the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 4), in the Cochrane Library; MEDLINE (1966 to 25 May 2020); Embase (1980 to 25 May 2020); the Index to Scientific and Technical Proceedings (1980 to 2019); the Web of Science Core Collection; ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) portal. We handsearched relevant journals and conference proceedings, checked reference lists, and contacted experts in the field.

Selection criteria: 

Randomised and quasi-randomised trials (RCTs) comparing one type of carotid patch with another for CEA.

Data collection and analysis: 

Two review authors independently assessed eligibility, risk of bias, and trial quality; extracted data; and determined the quality of evidence using the GRADE approach. Outcomes, for example, perioperative ipsilateral stroke and long-term ipsilateral stroke (at least one year), were collected and analysed.

Main results: 

We included 14 trials involving a total of 2278 CEAs with patch closure operations: seven trials compared vein closure with PTFE closure, five compared Dacron grafts with other synthetic materials, and two compared bovine pericardium with other synthetic materials. In most trials, a patient could be randomised twice and could have each carotid artery randomised to different treatment groups.

Synthetic patch compared with vein patch angioplasty
Vein patch may have little to no difference in effect on perioperative ipsilateral stroke between synthetic versus vein materials, but the evidence is very uncertain (odds ratio (OR) 2.05, 95% confidence interval (CI) 0.66 to 6.38; 5 studies, 797 participants; very low-quality evidence). Vein patch may have little to no difference in effect on long-term ipsilateral stroke between synthetic versus vein materials, but the evidence is very uncertain (OR 1.45, 95% CI 0.69 to 3.07; P = 0.33; 4 studies, 776 participants; very low-quality evidence). Vein patch may increase pseudoaneurysm formation when compared with synthetic patch, but the evidence is very uncertain (OR 0.09, 95% CI 0.02 to 0.49; 4 studies, 776 participants; very low-quality evidence). However, the numbers involved were small.

Dacron patch compared with other synthetic patch angioplasty
Dacron versus PTFE patch materials 

PTFE patch may reduce the risk of perioperative ipsilateral stroke (OR 3.35, 95% CI 0.19 to 59.06; 2 studies, 400 participants; very low-quality evidence). PTFE patch may reduce the risk of long-term ipsilateral stroke (OR 1.52, 95% CI 0.25 to 9.27; 1 study, 200 participants; very low-quality evidence). Dacron may result in an increase in perioperative combined stroke and transient ischaemic attack (TIA) (OR 4.41 95% CI 1.20 to 16.14; 1 study, 200 participants; low-quality evidence) when compared with PTFE. Early arterial re-stenosis or occlusion (within 30 days) was also higher for Dacron patches. During follow-up for longer than one year, more 'any strokes' (OR 10.58, 95% CI 1.34 to 83.43; 2 studies, 304 participants; low-quality evidence) and stroke/death (OR 6.06, 95% CI 1.31 to 28.07; 1 study, 200 participants; low-quality evidence) were reported with Dacron patch closure, although numbers of outcome events were small. Dacron patch may increase the risk of re-stenosis when compared with other synthetic materials (especially with PTFE), but the evidence is very uncertain (OR 3.73, 95% CI 0.71 to 19.65; 3 studies, 490 participants; low-quality evidence).

Bovine pericardium patch compared with other synthetic patch angioplasty
Bovine pericardium versus PTFE patch materials 

Evidence suggests that bovine pericardium patch results in a reduction in long-term ipsilateral stroke (OR 4.17, 95% CI 0.46 to 38.02; 1 study, 195 participants; low-quality evidence). Bovine pericardial patch may reduce the risk of perioperative fatal stroke, death, and infection compared to synthetic material (OR 5.16, 95% CI 0.24 to 108.83; 2 studies, 290 participants; low-quality evidence for PTFE, and low-quality evidence for Dacron; OR 4.39, 95% CI 0.48 to 39.95; 2 studies, 290 participants; low-quality evidence for PTFE, and low-quality evidence for Dacron; OR 7.30, 95% CI 0.37 to 143.16; 1 study, 195 participants; low-quality evidence, respectively), but the numbers of outcomes were small. The evidence is very uncertain about effects of the patch on infection outcomes.

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