TORONTO - Placing a stent-graft in the descending thoracic aorta during surgical repair of the proximal aorta of patients with acute DeBakey type I dissection is becoming an increasingly popular approach. A suggested advantage of this approach is the avoidance of subsequent, high-risk operations to repair the descending and thoracoabdominal aortic segments in those patients whose chronic dissection causes later aneurysm formation.

Dr. Joseph S. Coselli presented a study that he and his colleagues at the Baylor College of Medicine undertook to better define the risks associated with these secondary operations that stenting is suggested to avoid. They found that the use of open repair showed excellent early survival and acceptable morbidity and the use of adjuncts to protect against ischemic complications was associated with improved early outcomes.

Dr. Joseph S. Coselli said the use of adjuncts is associated with improved outcomes.

"We prospectively examined our contemporary experience with open distal aortic repair in patients with chronic DeBakey type I aortic dissection in 200 consecutive patients with open descending thoracic (n = 29) or thoracoabdominal (n = 171) aortic repairs. Data were collected between January 2005 and June 2013," said Dr. Coselli at the annual meeting of the American Association for Thoracic Surgery.

The median patient age was 57 years, and the median interval between initial proximal aortic repair and the subsequent distal operation was 4.8 years. In 30 patients (15%), repairs were prompted by the onset of acute symptoms; this included 10 patients (5%) who had a new acute DeBakey type III dissection superimposed on the chronic dissection. Forty-three repairs (22%) were emergent or urgent, and hypothermic circulatory arrest was necessary in 17 (9%).

Of the 171 thoracoabdominal aortic repairs, 145 (86%) were Crawford extent I or II; adjuncts used during thoracoabdominal procedures included cerebrospinal fluid drainage in 159 patients (93%), left heart bypass in 128 (75%), and cold renal perfusion in 123 (72%). The researchers used univariate and bivariate analyses to examine associations between potential risk factors and early death.

There were 14 early deaths (7%) and 35 late deaths, yielding an actuarial 6-year survival of 71%. Two patients (1%) developed permanent paraplegia, 4 (2%) had permanent paraparesis, 10 (5%) had strokes, and 9 (5%) had permanent renal failure necessitating dialysis. Greater age and the use of hypothermic circulatory arrest were significantly associated with early death. The use of left heart bypass and the use of cold renal perfusion were each significantly associated with early survival. There were no associations between early death and connective tissue disorders, emergent or urgent surgery, or extent of aortic repair, Dr. Coselli added.

"For our patients who survived DeBakey type I aortic dissection and subsequently develop distal aortic aneurysms, the use of open repair of the descending thoracic or thoracoabdominal aorta results in excellent early survival and acceptable morbidity. We found that the use of adjuncts to protect against ischemic complications is associated with improved early outcomes," Dr. Coselli stated.

In an interview, Dr. Coselli added that it is important to note that the disease process leading to late aneurysm after DeBakey type I dissection is likely much different than it is for the typically older cohort of distal aortic repairs for purely aneurysmal disease. The DeBakey I patients are about a decade or more younger and seem to have much less atherosclerotic disease. "We use the need for visceral endarterectomy as a marker for this," he said.

And, since older age is one of the best predictors of operative mortality and adverse event, the DeBakey I patients tend to do better than the typical older cohort undergoing open distal aortic repair. This is despite the fact that the vast majority of patients had an extensive history of prior aortic repair, including 35 repairs with prior open distal aortic repair or prior TEVAR (and naturally, extensive prior proximal aortic repair).

"The rate of permanent paraplegia was low, we speculated that the progressive nature of late distal aortic dilatation contributes to this low rate. Often DTA repair is followed by TAAA repair or vice versa. This is similar to the 'staged model' of distal aortic repair that Dr. Randall Griepp and Dr. C.D. Etz have published [Eur. J. Cardiothorac. Surg. 2008 34(3):605-14], possibly allowing for collateral circulation. This combined with our aggressive reattachment strategy for intercostal/lumbar arteries, may have contributed to this low rate," he added.

"Lastly, the reintervention rates for antegrade TEVAR and frozen elephant trunk tend to be high, and there is concern for an enhanced risk of paraplegia during these types of repairs. And with standard TEVAR, the rates of reintervention in patients with chronic dissection appear greater than those with only an aneurysm," Dr. Coselli concluded.

The authors of the study reported having no conflicts.

mlesney@frontlinemedcom.com

Open repair of acute DeBakey type I dissection favorable