Discussion

Dr Walter McCarthy (Chicago, Ill). Tell us now what you have done as far as using endovascular techniques. What is your protocol at this point? You have gone back over your data. You have convinced yourself that you might be able to use it. What have you done?

Dr Girma Tefera. Thank you for the question. Since we reviewed this data we have a protocol in place to treat an endovascular patient who may present with complications requiring surgery. In fact, we recently had a case of acute type B dissection with occlusion of the aorta at the celiac artery. This patient presented with paraplegia, anuria, and abdominal pain. We were able to open the true lumen with balloon mounted palmaz stents deployed across the occluded segment. Although this procedure temporarily was successful, it reoccluded 48 hours later. The patient was then taken to surgery for aortic replacement. Intravascular ultrasound was very helpful in identifying the true lumen. If I am faced with a similar situation, I will probably try to address the proximal tear also with covered stent graft.

Dr Michael Dalsing (Indianapolis, Ind). Very nice paper, Dr Tefera. Why do you think that having a prior aortic aneurysm repair makes things worse and that you have to operate on them more quickly than if they do not?

Dr Tefera. The short answer to your question is, I do not know. It is, however, interesting that this same phenomenon was observed during thoracic endograft trials. This may have something to do with the absence of lumbar arteries in the infrarenal aorta.

Dr John Matsumura (Chicago, Ill). I don’t know about why open repair might make it risky, but I have noticed in the patients who have an endovascular infrarenal repair who develop a thoracic dissection that it is a very lethal combination because it tries to stent open the true lumen, and because both legs feed off the true lumen, oftentimes the legs create a huge outflow and increase the chance for true lumen collapse. Roy, have you seen patients after infrarenal repair who have type B dissection? I have seen two cases where it is a very bad combination.

Unidentified speaker. We wrote up one case after an endograft with an aortic dissection where the fixation and the seal in the iliacs was so much stronger so that the false lumen kind of terminates in the aneurysm sac and crushed the endograft itself. That was probably a year or two after an endo AAA repair, but I have not seen a lot of dissections in those endo repair patients, infrarenal endo repairs, or open repair patients. I mean, I have always viewed open repair as a little bit protective of dissection because it always prevents the dissection from going down to the iliacs but I do not know. Your data are very interesting.

Unidentified speaker. We have seen two patients with aortic occlusion who had infrarenal aortic aneurysms and later dissection. One was an endograft and one was a standard repair. I think it can occur with either patient. Both were successfully treated for their aortic occlusion with fenestration and revision. The endograft we had to explant which was kind of a chore in the fact of an acute dissection but it was able to be done.

Dr Jacobs–Don v Chad. I would question your conclusion. One of them was that we should not be treating ______ currently ______ with an endograft. I am not arguing that point, but I am not sure that your data would say that because we do not know what they die of. With your survival curve there looking pretty steep on these patients, I think you would have to know what those complications potentially of the dissection are down the line that you may be able to prevent. That may be the mortality that you are seeing in your survival group.

Dr Tefera. I think the point I indirectly wanted to make was when you are successful treating these patients medically the mortality rate of 1.6 is very hard to argue with because when you see stent graft placement in dissection settings, high technical success is reported but the mortality rate is not that low yet. That is why I question and basically want to bring this point up, but I think when we followed our patients, about a third them do require elective surgery for further aneurysm expansion. We did not go specifically to see of those who died during follow-up why they died, but you also saw that from the curve point of view the 1-year survival was 85% when they were successfully medically treated.

Dr Roy Greenberg (Cleveland, Ohio). I think that your results are right on in terms of the low mortality rate associated with medical therapy for uncomplicated dissections, but something that we have struggled with is how to define optimal medical therapy because it varies so much. So I was wondering if you had a system for how you looked at patients. When was medical therapy optimal and what was the drug regimen? Were they always beta-blockers? Did you combine beta-blockers with ACE inhibitors? How did you manage those patients?

Dr Tefera. At our institution all patients who come in with type B dissection come to the Vascular Surgery Service, and we basically admit all of them. Unless there is a life-threatening, limb-threatening situation that needs to go to the operating room, these patients will all go to the intensive care unit, have an arterial line placed, and we have preprinted orders for esmolol drips and nitroglycerin to be started right away. On top of that, we start of a course oral medications to supplement. We take actually several days of ICU stabilization prior to these patients being transferred to the floor. In fact, if you look at the hospital length of stay for successful medical therapy patients, it is almost the same as for those who needed surgery. We take really our time and we have liberal usage of the maximum dosage of esmolol and nitroglycerin, and occasionally nitroprusside, and we transition them as quickly as possible into an oral regimen.

Of course they all go home with a lot more oral medication than what they had before, and we communicate with the primary care physicians prior to their being discharged. We really take total control, and of course medical therapy might be a failure sometimes, but it does not really occur in terms of not being able to control the blood pressure, particularly, if you have a pseudocoarctation kind of picture is rare certainly and by having these patients on your service I think helps.