Valley Heart & Vascular Institute - Endovascular (Stent) Repair and Hybrid Procedures
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Endovascular (Stent) Repair and Hybrid Procedures

Endovascular Stent Graft
Endovascular Stent Graft

When thoracic aneurysm is present in the aortic arch or the descending thoracic aorta, less invasive therapeutic options may exist for treatment, that do not require use of the heart-lung machine, and often without any incisions in the chest whatsoever. Relative size criteria have not yet been established for aneurysms beyond the ascending portion, and while we still use 6 to 6.5 cm as a 'standard' cutoff for possible intervention, for more petite patients (shorter stature), we may intervene at smaller sizes, especially if a much less invasive procedure is feasible. The basic premise of endovascular stent grafting is as follows. A large caliber stent that has fabric on the outside of it (that starts out collapsed) is passed over a guide wire through a groin artery, using live X-ray (fluoroscopy). The device is positioned such that each end will land in relatively normal caliber aorta, but the middle part will span the aneurysm itself. When the stent graft is then expanded, the device ‘seals’ itself to the normal sized aorta that borders the aneurysm, and blood then flows through the stent graft, and does not allow any flowing blood to be in contact with, or to pressurize the aneurysm itself. In fact, over time, these aneurysms can be seen to shrink around the endograft. The advantages of such a procedure are the avoidance of a large chest incision and negligible interruption of blood flow to the lower body during the procedure. Many patients are able to be discharged to home by the 2nd post-operative day! An important risk that is intrinsic to descending thoracic aneurysm surgery (paraplegia due to spinal cord blood flow interruption) is somehow substantially less than with traditional open surgery. When certain clinical situations represent a higher risk for paraplegia (especially previous abdominal aortic surgery at a separate site), we employ certain protective maneuvers to avoid this devastating complication, and we have been fortunate thus far with our outcomes.

Unfortunately, ascending aneurysms cannot yet be handled by endovascular therapies, but may be in the future. One area that has benefited dramatically from this new technology is aortic arch aneurysm. Traditionally, total arch replacement was considered to be amongst the most risky cardiac procedures that could be performed. The stroke risk was quite high, and these operations usually required cooling the patient using the heart-lung machine (‘pump’) to a temperature of 18 degrees Celsius, and literally turning the pump off for the duration required for this complicated reconstruction. In the modern era, we can now handle arch aneurysms without even needing the heart-lung machine at all. We utilize a hybrid approach wherein the aortic arch is ‘de-branched’ by sewing bypass grafts to the aortic arch blood vessels, and then deploying an endograft to span the arch aneurysm. This approach has dramatically lowered the morbidity and risk of total arch replacement.

Aortic Arch ‘de-branching' Aortic Arch ‘de-branching'

Aortic Arch ‘de-branching'

One other particularly tricky type aneurysm to handle, called ‘thoraco-abdominal aneurysm’ spans the diaphragm, and involves an aortic segment where the arteries that supply our abdominal organs and kidneys originate. This is typically treated with a very large incision (spanning the chest and abdomen), and often utilizing some form of cardiopulmonary bypass. These patients are usually quite a bit sicker than your average aneurysm patient (more medical problems in general), and the risk of open repair is substantial. It turns out that this is also a site that could potentially be ‘de-branched’ and an endograft deployed across the aneurysm in order to complete repair without ever having to actually directly handle the aneurysm itself. Though the world-wide experience with this approach for thoraco-abdominal aneurysms is limited, it has been gaining interest, especially in more experienced centers.

For more information, contact Leanne Scaglione, R.N., MSN, APN-BC, Coordinator for the Thoracic Aneurysm Surveillance Program, at 201-447-8398.

 

 
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