Editor: Robert M. Friedlander, MD, MA Associate Editor: Murat Gunel, MD
Chairman's Message By Robert E. Harbaugh, MD, MA
This issue has become even more important in light of recent developments in the International Subarachnoid Aneurysm Trial (ISAT). Patient accrual in this randomized trial of endovascular versus surgical treatment for patients with intracranial aneurysms has been stopped. Although no data have been published for review, the word on the street is that the trial was stopped because of significantly higher morbidity at one year in the surgical group. Expedited publication of the data is anticipated. Of course, a thorough review of the ISAT methodology and data will be needed. However, we also need to think critically about what kind of trial needs to done to determine the best treatment for an individual patient harboring an intracranial aneurysm. I would like to devote the majority of this message to a discussion of this issue.
Let me clearly state my prejudice in this matter. I believe that any short duration trial that purports to show that endovascular or surgical treatment of intracranial aneurysm is "superior" is likely to be misleading and will cause more harm than good for aneurysm patients. What we really need to know is which treatment--endovascular, surgical or combined--most benefits a given patient for the duration of his life. To do this we will need to evaluate many patients for many years following treatment. Let us postulate that the procedure-related morbidity of microsurgical aneurysm treatment is higher than the procedure related morbidity of endovascular treatment. This may be related to a relatively small number of endovascular specialists who have great experience or to an inherently greater risk of open surgical procedures regardless of the specialist's experience. However, we don't really know the long-term efficacy of either aneurysm clipping or coiling for preventing subarachnoid hemorrhage (SAH). If clipping is considerably more efficacious, then it may be the preferred treatment even if the procedure-related morbidity is higher.
Achilles Papavasiliou, MD, James McInerney, MD, Darby Pope, MD, and I recently completed a formal decision analysis of the treatment of unruptured aneurysms (presented at the AANS meeting in Chicago). Our baseline case cohort consisted of patients, age 40, who were neurologically well and who harbored intracranial aneurysms amenable to either surgical or endovascular treatment. We assumed that the annual risk of rupture for aneurysms chosen for treatment was 1.46 percent. Surgical treatment had a procedure related morbidity and mortality of 11.1 percent and was 95 percent effective for preventing future SAH. Endovascular therapy had a procedure-related morbidity and mortality of 5.6 percent, and was 75 percent effective for preventing future hemorrhages. Actuarial risks were obtained from U.S. Health Statistics tables, a standard discount rate for later years of life was used and the utilities of outcomes categories were obtained using a standard gamble methodology on a risk aversive, medically sophisticated group of physicians, nurses and medical students. Using the assumptions stated above, our decision analysis model indicated that for our 40 year-old patient cohort, the greatest number of quality adjusted life years would accrue to those patients treated microsurgically. The greater efficacy of surgery more than offset the higher surgical morbidity. However, the crossover point at which surgery became the preferred option did not occur until 10.5 years of follow-up. In other words, if the numbers in our model are correct, a randomized study of such patients would need a greater than 10-year follow-up on all patients to document the benefit of surgical treatment. A shorter study would have been misleading.
Let me clearly state that I am not sure whether or not the efficacy rates in this model are correct. Does surgery really reduce the annual risk of aneurysm rupture from 1.46 percent to 0.07 percent, and does coiling really reduce the annual risk of rupture from 1.46 percent to 0.4 percent? I don't know. The point is that no one knows if these numbers are correct or not. To find out we will need to do truly long-term studies. Based on our decision analysis modeling, a trial of endovascular versus surgical treatment for unruptured aneurysms would need to be carried out for approximately 20 years to show an unambiguous benefit for surgical treatment if clipping is 20 percent more efficacious than coiling at preventing SAH. Although this seems like an unreasonably long time, we must remember that our 40 year-old patients, 20 years from surgery, still have life expectancies of 15 years. We are trying to find an effective treatment for preventing SAH for decades, not months.
In conversations with some of my colleagues I have heard the statement that "The NIH will not fund studies for longer than three years, so it is necessary for us to do shorter studies." The appropriate response is, "If a short-term study is likely to yield misleading data, the honest investigator should have the intellectual integrity to refuse to participate, regardless of how much money and prestige a grant represents." Be assured that the SCVS will vigorously support a grant that adequately evaluates the relative risks and benefits of microsurgical and endovascular therapy for intracranial aneurysms. We will be equally vigorous in our opposition to studies that we think are likely to yield misleading data.
I also want to report on the financial status of the SCVS. In my first message I promised that the SCVS leadership would exert due diligence to assure that we are meeting our fiduciary responsibilities. I am happy to report that the budgets for fiscal year 2002 and 2003 look very good. Starting with this issue of Cerebrovascular News, we will no longer be printing and mailing a hard copy to the SCVS members. The newletter will be published online and an e-mail announcement will be sent to all SCVS members to notify them of its availability. Those who want to print a hard copy from their computer can do so. This change will save the section about $25,000 annually. I believe these funds can be used more wisely to benefit our members and the specialty of cerebrovascular surgery by contributing to the AANS/CNS Washington Committee, funding research awards and fellowships and sponsoring numerous other activities. Of course, it will be a loss that my words of wisdom and stunning photograph (autographed glossy available on request) will not appear in every neurosurgery office mailbox, but this is a loss I think we can deal with.
The section's 2002 annual meeting in Dallas was a great scientific and financial success. Congratulations to Robert Rosenwasser, MD, who chaired the meeting, and to Gregory Thompson, MD, the Scientific Program chair. We hope to duplicate this success with the 2003 meeting in Phoenix Feb. 16-19. Dr. Thompson is the Annual Meeting chair and Harold Pikus, MD, is the Scientific Program chair. They are planning a superb meeting with a variety of special courses, a stimulating and exciting scientific program and enjoyable social events. Don't miss this meeting!