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Updated: Jul 4, 2025
Surgical Technique for the Implantation of Tissue Engineered Vascular Grafts and Subsequent In Vivo Monitoring
Published on: April 3, 2015
Realtime monitoring of thrombus formation in vivo using a self-reporting vascular access graft
Daniel Hoare1, David Kingsmore2, Michael Holsgrove3
1School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK.
Insights
A new system uses electrical impedance spectroscopy sensors and radiotelemetry to monitor synthetic arteriovenous grafts. This technology enables real-time, wireless detection of blockages, potentially preventing graft failure in dialysis patients.
Area of Science:
- Biomedical Engineering
- Cardiovascular Research
- Medical Devices
Background:
- Chronic kidney disease (CKD) impacts 10% of the global population, with significant cardiovascular risks.
- Synthetic arteriovenous grafts (AVGs) are crucial for dialysis access but are prone to neointimal hyperplasia, leading to thrombosis and failure.
Purpose of the Study:
- To develop and evaluate a novel system for real-time, in vivo monitoring of synthetic arteriovenous grafts.
- To enable early detection of complications like venous stenosis and thrombosis in AVGs.
Main Methods:
- Integration of electrical impedance spectroscopy (EIS) sensors into the AVG wall.
- Utilization of an implantable radiotelemetry system for wireless data transmission.
- In vitro testing with cell cultures and blood, followed by in vivo implantation in swine.
Main Results:
- The system successfully detected and wirelessly reported the accumulation of biological material (cells, blood).
- Distinguished between normal and pathological conditions, including atheroma.
- Remotely monitored graft blockage formation in swine.
Conclusions:
- Combining EIS and radiotelemetry offers a promising approach for continuous graft surveillance.
- Enables early detection of venous stenosis and blood clot formation in real-time.
- Potential applications extend to other cardiovascular implants and diseases.
Background:
Chronic kidney disease (CKD) affects 10% of the global population costing over a hundred billion dollars per annum and leading to increased risk of cardiovascular disease. Many patients with CKD require regular haemodialyses. Synthetic arteriovenous grafts (AVG) are increasingly used to provide rapid vascular connection for dialysis. Initially, they have excellent patency rates but are critically limited by neointimal hyperplasia at the venous anastomosis, which drives subsequent thrombosis, graft failure and death.
Methods:
Here, we describe a system in which electrical impedance spectroscopy sensors are incorporated circumferentially into the wall of a synthetic arteriovenous graft. This is combined with an implantable radiotelemetry system for data transmission outside the patient. The system was tested using monolayers of endothelial and smooth muscle cells as well as swine blood and clots with explanted human carotid artery plaques. Sensor testing was then performed in vitro and the device was implanted in vivo in female swine.
Results:
The device can wirelessly report the accumulation of biological material, both cells and blood. Differences are also detected when comparing controls with pathological atheroma. In swine differences between blockage formation in a graft were remotely obtained and wireless reported.
Conclusions:
Combining electrical impedance spectroscopy and an implantable radiotelemetry system enables graft surveillance. This has the potential to be used for early detection of venous stenosis and blood clot formation in real-time in vivo. In principle, the concept could apply to other cardiovascular diseases and vascular implantable devices.
