The Sree Chitra Tirunal Institute for Medical Sciences & Technology (SCTIMST), in collaboration with the National Aerospace Laboratories, Bengaluru (CSIR-NAL), has indigenously developed an affordable stent graft and its delivery system for repairing thoracic aortic aneurysm.
Thoracic aortic aneurysms (TAAs) have an estimated incidence of at least 5-10 per lakh population.
An aortic aneurysm is a ballooning or enlargement of the aorta. A disease affecting about 5% of the population in their late sixties, it does not present any symptoms but can be fatal in case of rupture.
Endovascular Aortic Repair or EVAR is a minimally invasive technique which involves the insertion of stent grafts in the diseased vessel by a delivery catheter, which is inserted into the central circulatory system through the femoral artery.
Surgeons currently use imported stents which cost over ₹3.5 lakh. However, the imported stent graft and its delivery system are not exactly designed for the Asian population. The catheter diameter is often large, making it difficult to insert and pass through the femoral artery and this often results in injuries.
The stent graft developed by the SCTIMST is made up of polyester fabric sewed in tubular form and are scaffolded by NiTi (Nickel Titanium Alloy) rings. It has incorporated a new asymmetric design for the NiTi rings (stents), which can be adjusted to a lower diameter and inserted in a catheter sheath of lower diameter.
This asymmetric design helps the stent graft to affix itself to the inner aortic wall and resists displacement due to blood flow.
Once the stent graft is put in place, blood flow occurs only through the conduit, thus excluding the aneurysm and preventing its rupture.
Endoleak (Type-1) is a defect which occurs after the deployment of the stent graft in the aneurysm area. The device developed by the SCTIMST does away with this defect.
The delivery system incorporates a new feature for the fast release of the stent graft and accurate deployment of the device during the EVAR procedure.
Six patent applications and five design registrations were filed for the features.
The project team included Sujesh Sreedharan, Engineer-F, Division of Artificial Internal Organs, Biomedical Technology Wing; Jayadevan E.R., Additional Professor, Imaging Sciences and Interventional Radiology; Santhosh Kumar K., Additional Professor, Imaging Sciences and Interventional Radiology, SCTIMST; and Unnikrishnan M., former Professor, Cardiovascular and Thoracic Surgery.
