A Look at Ascending Aorta Repair by Endovascular Stent Grafting

By Eric E. Roselli, MD

Every year, Cleveland Clinic surgeons perform more than 600 elective operations on ascending aortas, with a low mortality rate. Nevertheless, some patients are considered too high risk for conventional repair.

From 2006 to 2014, we treated 22 such patients using an endovascular approach. They were selected because they had favorable morphology believed to be amenable to definitive repair or unfavorable morphology that put them at immediate risk of death without mechanical intervention. All were believed to have the potential for a meaningful recovery because they had enjoyed a decent quality of life before their emergency.

Our group and others have described the use of thoracic endovascular aorta repair (TEVAR) of the ascending aorta as case reports or small series. Although still limited in number, the collected experience with this approach to these 22 patients is one of the largest to date and has proven to be instructive. In our paper published in the Journal of Thoracic and Cardiovascular Surgery, we examined patient characteristics, methods and outcomes, including an engineering analysis of device and procedural limitations.

Patient characteristics

The mean age of patients was 71 ± 13 years. Nine had acute Type A dissection, two had an intramural hematoma with penetrating ulcer in the ascending aorta, nine had pseudoaneurysms and two had complicated chronic dissections. Of these, two had contained ruptures complicated by aorta-cardiac fistulae.

Computed tomography images were analyzed using three-dimensional reconstructions to assess the diameter at the proximal and distal landing zones, measure the length of the aorta along the greater and lesser curves, and gather details about the branch vessels and location of the entry tear in relation to the aortic root. The information was used to plan the procedures.

All procedures were performed under general anesthesia in a hybrid operating room with fixed imaging. In one patient, the procedure was performed using cardiopulmonary bypass; in the others, it was done with rapid ventricular pacing to facilitate accurate device deployment.

Stent grafts were placed in 21 of 22 patients. The devices were delivered transfemorally in 10 patients, through transaxillary access in five, and through transapical access in seven. A Zenith® extension cuff device (Cook, Bloomington, IN) was the most commonly used stent graft, but some were custom-made as part of an investigational device exemption (IDE), and others were modified versions of commercially available thoracic stent grafts.

In one patient, we were unable to cross a mechanical valve with a stent graft, so we used an atrial-septal defect closure device to close a fistula between a pseudoaneurysm and the right main pulmonary artery. The endovascular procedure served as a bridging procedure that relieved his cardiogenic shock related to shunting, and the patient had successful open repair later.

Issues and outcomes

Operative mortality (in-hospital or 30-day) occurred in only three patients (13.6%). There were three strokes, two myocardial infarctions and two tracheostomies, but no patient suffered dialysis-dependent renal failure.

One 85-year-old patient died on the table due to the complexity of his disease. Although we were able to seal the hole in his ascending aorta, his ruptured aorta had eroded into the dome of his left atrium, and he bled out after the ascending aorta was sealed off. He was not a candidate for conversion to open repair.

Two patients required conversion to open surgery at the time of the procedure, one due to a retained delivery system and one due to a partial coronary obstruction. Devices were deployed inaccurately in two patients, and we salvaged them with endovascular balloon repositioning of the devices.

Outcomes were acceptable in this high-risk group of patients. Survival at 30 days, 1 year and 5 years was 86, 77 and 73 percent, respectively. Four patients required later open conversion. There were three late deaths.

Several endoleaks occurred. Two were treated endovascularly, one was treated with open surgery, one resolved on its own and one patient is being monitored.<?p>

Lessons learned

We performed a focused engineering analysis of procedures and outcomes in an attempt to improve quality and understand how this operation can be improved. We found 22 potential areas for improvement that were patient-related, device-related or delivery-related.

It is clear that stent grafts for the treatment of disease in this segment of the aorta need to be specifically designed for this purpose. We need devices that are more conformable, precurved and shaped for the ascending aorta, and potentially with branches to accommodate the arch vessels. More accurate delivery systems are also needed to improve this technique.

Even in the absence of ideal technology, ascending endovascular therapy is feasible and can be an effective life-saving therapy. Patient selection is important, but its application as a bridging therapy may allow for broader use. With the development of better devices and delivery systems, I am certain that this technique will become more widespread.

References:

1) Roselli EE, Brozzi N, Albacker T, Lytle BW. Transabpical endovascular ascending repair for inoperable acute type a dissection. JACC Cardiovasc Interv. 1013 Apr;6(4):425-6

Eric E. Roselli, MD, is a staff surgeon in Cleveland Clinic’s Department of Thoracic and Cardiovascular Surgery and he is on the teaching faculty at the Cleveland Clinic Lerner College of Medicine.