Delay can reduce TEVAR problems with type B dissections



NEW YORK – Patients with acute type B aortic dissections who are treated with thoracic endovascular aortic repair within 48 hours of symptom onset are more than three times as likely to have a severe complication as are those who are treated between 2 and 6 weeks after initial presentation, according to Dr. Nimesh D. Desai.

"There has been a dramatic increase in survival of patients managed with TEVAR for life-threatening complications of type B dissection versus any other therapy. Recently, [FDA] approval of two devices in the U.S. (Gore cTAG and Medtronic Valiant Captiva TEVAR grafts) has really opened up the field of inquiry into the optimal timing of TEVAR in the nonemergent, non–life-threatening complicated type B dissection patient. In the current study, we analyzed the impact of timing of intervention," Dr. Desai said at the meeting sponsored by the American Association for Thoracic Surgery.

Between 2005 and 2012, 317 people were admitted to the Hospital of the University of Pennsylvania, Philadelphia, for acute (less than 6 weeks) type B dissections, said Dr. Desai. He reviewed the outcomes for 132 patients who had undergone TEVAR, dividing them into three groups according to the timing of the procedure: acute/early (TEVAR within 48 hours of symptom onset), n = 70; acute/delayed (TEVAR 48 hours to 14 days following symptom onset), n = 44; and subacute (TEVAR 2-6 weeks following symptom onset), n = 18. Patients in all three groups were generally between 63 and 65 years old. Most were men who had histories of severe hypertension and smoking. About 10% had a previous stroke.

Those in the acute/early group were more likely to have undergone TEVAR for life-threatening conditions. For instance, 43.28% of the acute/early group had a contained rupture vs. 25% of the acute/delayed and 11.11% of the subacute patients, a significant difference. The acute/early group also had higher rates of frank rupture and clinical malperfusion than did the other groups.

In contrast, 56% of the subacute group underwent TEVAR because they manifested "softer indications" of impending rupture or radiographic malperfusion, which were not considered to be as emergent. Three-quarters of the subacute group had already been discharged home and were readmitted for the procedure, reported Dr. Desai, who is at the University of Pennsylvania.

The overall rate of severe postoperative complications was 39% in the acute/early group, 27% in the acute/delayed group, and 11.1% in the subacute group, a significant difference.

In-house mortality was 8.5% in the acute/early group (nine patients), 4.5% in the acute/delayed group (three), and 0 in the subacute group, a nonsignificant difference. Similar, but nonsignificant trends were found in 30-day mortality (11.7%, 6.8%, and 0%) and stroke (5.6%, 4.6%, and 0%).

An opposite trend toward higher rates of paralysis was observed in the subacute group (7.04%, 4.5%, and 9.5%, respectively, in the three groups).

The incidence of retrograde type A aortic dissection was 8.5% in the acute/early, 6.8% in the acute/delayed, and 4.7% in the subacute groups. "Retrograde type A dissections are an iatrogenic disease caused by stenting type B dissections," said Dr. Desai. "They almost never happen with any other type of stent graft category."

He said that in his experience, the risk increases with excessive oversizing of stents and the dissections tend to occur at the interface between the native aorta and stent graft. In addition, he noted, many of the dissections occur a year or more after the original dissection.

"Delayed intervention appears to lower the risk of complications of TEVAR for aortic dissection in patients who are stable enough to wait. Our practice is to wait 10-14 days for remodeling indications," said Dr. Desai. Type B patients who are initially managed medically should be followed closely, he said, because they are at risk for the onset of new indications that might require TEVAR.

Operator experience and adequate case planning are critical when treating patients in the setting of acute or subacute type A dissections, Dr. Desai said, adding that the development of devices specific for dissections, rather than those designed for aneurysm pathologies, may lead to fewer complications.

Dr. Desai is a primary investigator for Food and Drug Administration TEVAR trials for W.L. Gore and Associates, Medtronic, and Cook Medical.