The Division of Angiography and Thoracic Surgery are proud to be able to offer the investigational use of thoracic and abdominal stent grafts.  The Health Sciences Center is part of an investigational protocol using stent grafts to treat select patients with descending thoracic aortic aneurysms and also with infrarenal abdominal aortic aneurysms.

Patients with known aneurysms are first evaluated in the Vascular Surgery Clinic and in the Angiography Suite.  Patients are screened initially with a CT scan. Subsequently, patients undergo an angiogram of the area of interest.  Intravascular ultrasound (IVUS) is also used to carefully measure the diameter of the aorta proximal and distal to the aneurismal segment.

If this initial evaluation reveals that the patient is still a candidate for stent graft placement, the patient will be enrolled in the study.  Patients enrolled in the study will need close follow up with repeat CT examinations prior to discharge from the hospital, at one month post procedure, 6 months post procedure, and at one year post procedure.  As long as this device remains investigational the patients will also require annual CT examinations.

Patients who are found to meet the selection criteria and are willing to consent to the protocol will be scheduled for a combined interventional radiology and thoracic surgery procedure. This procedure is performed in an operating room compatible angiography suite in the Division of Angiography and Interventional Radiology. Access is gained into both common femoral arteries using vascular cut down techniques. The stent graft devices introduced and advanced under fluoroscopic guidance to the level of the aneurysm.

An additional catheter is placed through the contra lateral groin or a brachial access to provide repeat contrast injections. Once the device has been carefully positioned at the site of aneurysm it is unsheathed and springs open to a predetermined size.

A stent graft is a metal mesh with Dacron material sutured to it.  The stent grafts used in this study have a modular design. This means that if the initial device is not completely cover the aneurysm additional segments can be added until a satisfactory result is obtained. Even aneurysms that extent down into the iliac bifurcation can be managed with a bifurcated stent graft.  At the completion of stent deployment, a repeat angiogram is performed.  If device deployment is satisfactory, the cut down sites are closed. Patients occasionally need a small patch placed in the artery at the cut down site. Patients are traditionally observed for approximately 3 days post stent graft placement. Prior to discharge, a CT examination is obtained.

This CT confirms that the stent graft is in the appropriate position and is also used to evaluate whether any contrast can be visualized into the aneurysm sac, which has been excluded by the stent graft.  Small leaks are commonly found at this time.  These are most often due to continued filling of the aneurysm through retrograde flow small aortic branches (either intercostal arteries or lumbar arteries).Fortunately, follow up studies indicate that most of these endoluminal leaks spontaneously close.

The long-term efficacy of this device is unknown.  Although the aneurismal sac can be excluded in most patients, the long-term outcome of these patients needs further investigation