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Open repair is the better procedure.
It’s my contention that open repair is still the gold standard for chronic thoracoabdominal aortic dissection. It has a record of outstanding results in high-volume centers of excellence with low morbidity and mortality and very good long-term survival. It has no anatomical constraints. It’s a durable repair and there are no device- or procedure-related proximal and/or distal aortic complications. Reintervention on the operated segment is very rare.1-6
Thoracic endovascular repair (TEVAR), despite having very good procedural results, has challenges in the successful treatment of chronic aortic dissection. Morbidity is low, as are rates of spinal cord ischemia, stroke, and renal failure. However, thoracic remodeling at the level of the endograft is in the 70%-88% range, which means that 12%-30% of patients do not have protection in the form of reverse aortic remodeling. In the abdominal aorta, remodeling is uncommon, with 11%-23% thrombosis of the false lumen even with advantageous anatomy. Survival in several series is in the 60%-80% range at 3 and 5 years. TEVAR creates new challenges for chronic thoracoabdominal aortic dissection: retrograde type A dissections have been as high as 2%-7%; 15%-30% of cases require intervention; and stent graft-induced new entry (SINE) has been reported as high as 36%.
Dr. Joel Corvera
Specific anatomical features are not suitable for TEVAR. They include multiple visceral vessels off of the false lumen; multiple fenestrations, especially in the abdominal aorta; dissection within the dissection; and pseudocoarctation. The durability of the endovascular graft for chronic aortic dissection is unknown; it’s a relatively new procedure so the long-term data is lacking.
Success of the endovascular approach depends on aortic remodeling, and it’s my contention that the thoracic devices now available cannot effectively treat a chronic thoracoabdominal aortic dissection. There are steps surgeons can take to improve their success, but procedures specifically addressing the false lumen are not time-tested and thoracoabdominal-specific devices are not widely available in the United States. And of course, morbidity and mortality will increase with the complexity of the endovascular repair.
Our in-hospital outcomes with open repair of chronic thoracoabdominal aortic dissection using deep hypothermia and circulatory arrest have been excellent: mortality rate of 3.6%; a stroke rate of 1%; permanent spinal cord ischemia rate 2.6%; and a 0% rate of patients on permanent hemodialysis. Our hospital length of stay is approximately 12 days. Blood product transfusion is reasonable with a mean blood product transfusion of 9 units for the hospital admission. The reintervention rate is 1% for infected grafts, 3.1% for anastomotic pseudoaneurysm and 3.6% for growth of a distal aneurysm. Long-term survival is very good: 93% at one year; 79% at five years; and 57% at 10 years.
There’s no denying that mortality rates for endovascular repair are excellent. There’s no denying that open repair is much more invasive. And if the patient is of advanced age, is frail and has comorbidities, the endovascular repair can have a certain advantage.
But for false lumen obliteration, the advantage goes to open repair. With regard to reintervention, certainly the advantage is with open repair. For durability, from what we know currently, open repair has the advantage. There are no stent-induced new entries in open repair; and open repair can address any and all anatomy. A successful endograft repair requires fixation and seal in the appropriate aortic anatomy; it demands good proximal and distal landing zones. However, in chronic dissection, there is the added complexity of having to address the false lumen flow from an untreated abdominal aortic segment.
For patients with connective tissue disorders, open repair is still the gold standard. As for long-term survival, the advantage goes to open only because the endovascular approach is relatively new. If it’s done in high-volume centers with great experience, open repair has a mortality advantage as well.
Dr. Joel Corvera is an assistant professor of surgery and director of thoracic and vascular surgery at Indiana University, Indianapolis. He had no relationships to disclose.
1. Eur J Vasc Endovasc Surg. 2011 Feb;41:159-66.
2. J Thorac Cardiovasc Surg. 2011 Feb;141:322-7.
3. Ann Cardiothorac Surg. 2014 May;3:264-74.