External Stents for Vein Grafts in Coronary Artery Bypass Grafting: Targeting Intimal Hyperplasia
Luca Paolo Weltert1, Lorenzo Guerrieri Wolf2, Luigi Garufi3
1Heart Surgery Unit, European Hospital, Rome, Italy, Department of Statistics, San Camillus International University for Health Sciences, Rome, Italy.
Insights
External stents significantly reduce intimal hyperplasia and vein graft disease in coronary artery bypass grafting (CABG) patients. This innovative approach shows promise as a future standard of care for improving saphenous vein graft (SVG) longevity.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Vascular Biology
Background:
- Saphenous vein graft (SVG) failure is a major obstacle in coronary artery bypass grafting (CABG).
- Intimal hyperplasia is the primary cause of SVG disease after one year, leading to thrombosis and atherosclerosis.
- External stenting is an emerging strategy to address SVG failure.
Purpose of the Study:
- To review and summarize current experimental and clinical data on mechanical external stents for vein grafts.
- To evaluate the efficacy of external stenting in preventing intimal hyperplasia and improving SVG outcomes.
Main Methods:
- A systematic literature search was conducted in PubMed using keywords: "external stent", "CABG", "saphenous vein graft", and "intimal hyperplasia".
- Included studies were randomized experimental and clinical trials assessing the impact of external stenting on venous intimal hyperplasia and clinical benefits.
Main Results:
- Pre-clinical studies in animal models demonstrated that external stenting significantly reduced intimal hyperplasia, thrombosis, and lumen irregularities.
- Clinical trials with 1-4.5 years of follow-up confirmed these findings, showing a significant reduction in vein graft disease.
- External stenting proved safe and offered anatomical and cellular advantages.
Conclusions:
- External stenting provides significant benefits for saphenous vein grafts at both anatomical and cellular levels.
- The consistent positive results suggest that external stenting of SVGs may become a future standard of care in CABG procedures.
Introduction:
Progressive saphenous vein graft (SVG) failure remains a key limitation to the long-term success of coronary artery bypass grafting (CABG). SVG disease after the first year is dominated by intimal hyperplasia, which predisposes the SVG to thrombosis and accelerated atherosclerosis. The objective of this study was to review and summarize the latest experimental and clinical data on the use of mechanical external stents for vein grafts.
Methods:
In January 2020, the PubMed database was searched using the terms "external stent", "CABG", "saphenous vein graft" and "intimal hyperplasia". The results were reviewed and only randomized experimental and clinical studies that analyzed the effect of external stenting on venous intimal hyperplasia were included in the analysis, together with studies that investigated the clinical benefit of external stenting.
Results:
Eight experimental and four clinical trials met the search criteria. Controlled trials in different large animal models concluded that external stenting significantly reduced intimal hyperplasia 3-6 months post implantation, and reduced both thrombosis rates and the development of lumen irregularities. Data from randomized controlled trials with a follow-up period of 1-4.5 years supported the pre-clinical findings and demonstrated that external stents significantly reduced vein graft disease.
Conclusion:
Strong evidence indicates that supporting the vein with external stents is safe and leads to clear advantages at both the anatomical and cellular levels. With the further accumulation of consistent positive results, external stenting of SVG may become the standard of care in future CABG.
