Journal of Neuro-Ophthalmology, September 1989, Volume 9, Issue 3

Ocular manifestations of carotid artery occlusive disease. Panel discussion.

Journal of Clinical Neuro- ophtiUllmology 9( 3): 209- 210, 1989 Ocular Manifestations of Carotid Artery Occlusive Disease Panel Discussion Henry J. L. Van Dyk, M. D., Moderator © 1989 Raven Press, Ltd" New York Dr. Van Dyk: I would like to begin by asking questions. As a practicing ophthalmologist, sup­pose you saw a patient that has had episodes of ocular transient ischemic attacks ( TrAs), and oph­thalmoscopic examination disclosed a bright Hol­lenhorst plaque and/ or a retinal infarct. What would be your advice to this patient? Dr. Mills: The evidence is so strong that the pa­tient is at significant risk for coronary artery dis­ease and other vascular disease. I would first refer the patient to an internist for evaluation and treat­ment of any cardiovascular disease. Only later, if indicated, would I perform a carotid investigation, i. e., invasive carotid tests. Dr. Savino: I would almost follow the same ap­proach. When a patient presents with a Hollen­horst plaque, I first send them to a cardiologist, as an evaluation of the coronary artery circulation is very important. Furthermore, if they have hyper­tension, and they often do, the cardiologist can treat the elevated blood pressure as well. How­ever, in my office, such patients also undergo non­invasive carotid artery testing. Dr. McCrary: I tend to agree with the previous statements. The initial step should be an evalua­tion of the cardiovascular status of the patient. The need for additional carotid artery testing is deter­mined by the frequency of symptoms, especially cerebral hemispheric symptoms. If noninvasive studies show significant plaque, especially ulcer­ated plaque, and that patient has had many recur­rences of embolic disease and is failing under med­ical therapy, then I think one should consider sur­gical management, i. e., carotid endarterectomy. However, if surgery can be avoided, so much the better, Dr, Burde: I don't want the audience to have any misunderstandings regarding the referral of pa­tients for carotid endarterectomy, There are two things one has to evaluate before referring pa­tients. First, duplex scanning is dependent on the 209 skill of the technician. One cannot just send the patient to any lab without knowing the quality of the machine and the skill of the technician who is doing the study, Dependent on the quality of the machine and the skill of the technician, there can be considerable variation in results. The second consideration is the skill of the surgical team that is to do the operation. One should know what sort of results these people have had in the past. If the surgical team has a perioperative morbidity and mortality of less than 1%, one can encourage pa­tients to have surgery, as that is a very skillful surgical team, Both of these two factors have to be considered before recommending a carotid endar­terectomy. Thus, before reaching a final decision one must be assured that there has been an ade­quate evaluation and that there is an excellent sur­gical team available. Dr. Van Dyk: I have two questions for Dr. Patter­son. First, if an ophthalmologist was to refer a pa­tient to you directly for consideration for carotid endarterectomy ( because the patient has had ocu­lar TrAs or has had emboli in the retina), what sort of work- up do you employ before surgery? The second question is, " Who really is the best candi­date for carotid endarterectomy?" " Which patients are going to gain the greatest benefit from that operation?" Dr. Patterson: My work- up would be the same as the others have outlined. I always have a cardiol­ogist evaluate such patients, and I also do the ex­tracranial studies. I restrict my surgery to people with high grades of stenosis, i. e., 80%, 90%. Pa­tients with 50% stenosis are just observed. Also, the patient has to have a good prognosis for life. However, ultimately it is the patient's decision. I believe that the physician should present the data, but the patient should make the decision. After all, it is the patient's carotid artery and cerebral hemi­sphere. What might be inappropriate for one pa­tient, might be appropriate for somebody else. 210 PANEL DISCUSSION Some people, with severe disease in the carotid bifurcation, are very disturbed by the risk of stroke. In the proper hands, such patients should have surgery. There are currently two randomized studies of carotid surgery in progress. The study on symp­tomatic patients is being led by Henry Barnett and coworkers in Canada. This is the same group that directed the study of the efficacy of intracranial­extracranial bypass, about which there was criti­cism because a large number of patients in the par­ticipating centers were operated out of the study rather than being entered into the study. This prob­ably occurred because the treating physicians be­lieved that some patients needed the surgery, and hence, it would be unethical to randomize them to medical treatment. This cannot be allowed to hap­pen in the carotid artery study. If the operation is to be shown effective, it will mean that some pa­tients randomized to nonsurgical therapy will sus­tain a stroke that might have been prevented by operation. This idea is troublesome to those who feel strongly that the operation is efficacious, but the concept is now understood by the participants, and the result should be a better study. Dr. Van Dyk: Would you give the audience an idea of who you feel should have carotid endar­terectomy? Who would benefit? Dr. Trobe: It is hard to completely turn everyone away from carotid endarterectomy, especially as the weight of popular feeling in the medical com­munity is that this operation is useful. Each prac­titioner is wondering how to use the information that you heard today. Dr. Patterson and I are pretty much in agreement about this subject. As regards patients who should be considered for sur­gery, I have the following criteria: ( 1) they should be people who have a good chance of living more than 5 years; ( 2) they should be free of disease elsewhere; ( 3) they should be symptomatic, not asymptomatic. Symptomatic patients should have more than just visual manifestations to be consid­ered for surgery. Patients with just visual manifes­tations are not candidates, at least at this time. I admit that this is a difficult position to take, as we do not have enough information. That is why one either accepts randomized study data, or one does not. In the New England ! tJltrnal of Mcdicillc, this week, there's an exchange of letters on this very topic. Tim Johnson, who is the ABC's medical cor­respondant, wrote a letter in which he pleads with us to accept the information developed by ran­domized studies. He said that he is often an arbi­tnt" f ~, · tl' · P' · ' · : thr. nwo. ij,-" I ( flmmunity and the , · " Ii ( 0 , ldvise the I Clitl Ni'uru- ophtJwlrllof, Vol ~~, ,~" ~. I ', 1"- 1 public, as there is a lot of inaccurate information being circulated, I feel differently from Dr. Patterson in regard to the by- pass study, I think that study is a good study. Even if you exclude all the bad stuff that was in it, it still seems to hold up. I would look forward to the results of the endarterectomy stud­ies. In the meantime, we must be very skeptical; review all the anecdotal stories with great hesita­tion. Dr. Vall Dyk: Brian Younge is at the Mayo Clinic, which institution has established a reputation over the years as regarding stroke diagnosis. Has this new pendulum influenced the incidence of carotid endarterectomy surgery at your institution? Dr. Younge: No. I think I can qualify that by list­ing the indications for surgery. One of the reasons that the success rate of Mayo Clinic's operation in this area has been good is that multiple disciplines share the responsibility. Internists, cardiologists, and neurologists consult together quite a bit before calling in the neurosurgeon. Then, the neurosur­geon makes the decision with the patient. Also, we have always had a fairly good method of screening these patients. If they are in a high- risk category, and if it doesn't look like we are going to help the patient, the surgery is not offered. So, I think the way one picks the surgeon, and the institution, are important considerations. I certainly don't want the audience to think that we are not changing our ways. We have changed our ways. For instance, we are not doing tempo­ral- middle cerebral by- pass operations anymore. However, in our own little group, we have helped a lot of patients. You saw a couple of slides today of patients with venous stasis retinopathy who got better with the by- pass surgery. But those are iso­lated cases, and it is hard to get enough numbers to say this is statistically significant. We are continuing to do carotid endarterecto­mies. We are trying to select patients who we can help the most, and not treat those that might not be helped. The fact that we have a low morbidity and a low mortality rate is because of our surgical teams. We intend to persist with surgical endar­terectomies. Dr. Vall Dyk: Are you referring the same num­ber, or fewer numbers, of patients for carotid en­darterectomy? Dr. Blirde: Much fewer. Dr. McCrary: Fewer. Dr. Mills: Fewer. Dr. Sal'illo: Fewer. Dr. Trobe: Much fewer. Dr. Vall Dyk: This concludes the symposia.