When medication fails to halt type B aortic dissections
Date: June 13, 2011
The vast majority of patients with a type B aortic dissection—about 70 percent—can be treated effectively with blood pressure medications and vasodilators to prevent further separation of the inner lining of their aorta. But patients whose dissection is not managed effectively with medicine can develop serious complications, including kidney and liver failure, bowel damage and lack of blood supply to the leg. The blood, coursing down the false channel created by the dissection, can pool and block blood supply to vital organs.
“About 30 percent of patients with type B dissections can have significant malperfusion events,” says vascular surgeon James Black. “And sorting out which of those patients are at risk of complications is critical. Sometimes we can reverse these complications with ultratight blood pressure control and slowing down their heart rate. Other times, we have to resort to more invasive options.”
Surgical treatment to close the entry tear was abandoned in the 1980s because there was a 40 percent risk of patients becoming paralyzed from the waist down. In the last decade, less-invasive endovascular options have become available for treating aortic aneurysms, and while there are no FDA-approved stent grafts for treating type B dissections, some surgeons have used these devices off-label to close the channel in the aortic arch.
“However,” says Black, “stents made for aneurysms aren’t suitable for aortic dissections, especially in younger patients, because the stents are not flexible. If you put a stiffer stent into these patients, you’re risking damage to the aortic arch down the road.”
One possible answer to this treatment gap is a new type of “conformable” stent graft designed especially for aortic dissections. “Hopkins is one of the trial sites,” Black says. “We want to see if the flexible stent is more effective at treating the dissection and less damaging to the fragile aorta in the long run than the older, stiffer devices. The five-year trial began last year and is accepting patients.
Chris Gilbert, a resident of Maryland’s Eastern Shore, came in as an emergency referral to Black. Not only did Gilbert have a type B dissection, he also had a large abdominal aortic aneurysm. “He had a double-barrel aorta that required a more complex open procedure than the minimally invasive aneurysm repair we commonly perform,” says Black.
Gilbert was discharged five days later, continues to do well, but still has the type B dissection and will have to remain on blood pressure medicine to keep it in check. Black will be following him long-term, as he does with all of his patients who’ve had either type A or type B.
Unlike type B, type A dissections require emergency surgery. After the repair, patients should continue to be followed long-term because two-thirds of patients who have type A dissection remain at risk for type B. “The whole aorta can unravel beyond the descending aorta,” Black says. “There are lots of aftershocks from the original earthquake, so to speak. That’s why, here, we monitor patients for the rest of their lives.”
The Conformable GORE TAG
Thoracic Endoprosthesis TAG
08-01 Dissection Clinical Study
is enrolling patients with type B
dissections accompanied by
malperfusion syndrome or
rupture that has manifest within
14 days of initial presentation.
Info: James Black,