Discussion

Dr Marc A. Passman (Nashville, Tenn). Drs Armstrong and associates should be complimented on an excellent presentation and well-written manuscript. Based on evidence-based guidelines and as carryover from their participation in the ADAM trial, a continued surveillance program was established at James A. Haley Veterans Hospital in Tampa, Florida, in 1998 for ongoing observation of small 4.0- to 5.4-cm abdominal aortic aneurysms (AAA). During the 8-year period, 473 patients were evaluated, of which 139 required operation for AAA exceeding 5.4 cm and 334 entered the surveillance algorithm for AAA of 4.0 to 5.4 cm. For those within the surveillance program, the authors report only two AAA ruptures (0.6%) during surveillance and a cumulative aneurysm-related mortality of 0.9% for those following the surveillance treatment algorithm. This leads me to several questions.

First, with a captive VA population, a high compliance rate of 98.5% is reported with the surveillance algorithm, which included CT or ultrasound imaging biannually. While such a compliance rate is commendable, it may be more difficult to reproduce outside the VA system. Although some recommendations are provided based on their VA experience, do the authors have any additional recommendations for success in the “real world,” where cost and resources may be more problematic? After all, your group does not have a comparable program in the university arm of your practice.

Second, with a VA serving 8 counties and 436,000 veterans, the prevalence or incidence of AAA seems lower in this study than what would be expected in the general population with a similar risk profile, which suggests there are either patients with AAA who are not coming to your attention for enrollment or AAA is being under-diagnosed. Nationally, there is an increasing attention being placed on screening for AAA. What measures have the authors taken to combine their surveillance program with efforts at increased patient and provider awareness in their VA system to increase screening and identification of AAA, and thereby improve enrollment into the treatment and surveillance algorithm?

Third, for patients with AAA in the 4.0- to 5.4-cm range entering the surveillance program, 225 patients (67%) eventually required operative repair for size exceeding 5.4 cm or expansion exceeding 1cm/year, of which 143 (or approximately two thirds) underwent open repair and 82 (approximately one third), endovascular repair. With so many patients eventually requiring operation, was there any downside to delay now that the patients are older in terms of increased medical comorbidities compared to when they entered the program? How many of these patients were originally an endovascular candidate when entering the surveillance program but with AAA expansion are no longer?

Finally, the threshold size for operation used in the treatment algorithm is based on evidence based guideline related mostly to comparison of open repair and surveillance. While randomized trials comparing endovascular repair and surveillance for small AAA are still ongoing, early, nonrandomized data from our institution and others have suggested that endovascular repair of small AAAs is safe with low risk. Given that 67% of the patients in the surveillance program eventually required operation, were the authors able to retrospectively identify any factors that predicted expansion thereby supporting potential earlier AAA repair, especially for those who are endovascular candidates? Again, I congratulate the authors on their fine presentation and thank the Society for the privilege of discussing this paper.

Dr Paul A. Armstrong: In response to your first question, making the transfer of a surveillance program from a socialized system like the VA to private practice is indeed a challenge, but if we approach the problem by thinking outside of the box we can find some creative ways in which to create interest in these programs and defray cost; for example, regional societies and health management systems can be petitioned by their members or be coerced by cost savings to participate. Likewise, legislative pressure can be levied on third-party payers and health care systems to provide funding.

In answer to your next question, the primary care providers within the VA system have a health maintenance menu they complete at each patient visit. Beginning this year, there has been an addition to that menu that will include eligibility criteria for one-time abdominal aneurysm screening. This will provide a clinical reminder, if you will, for our primary providers and likely increase the effectiveness of aneurysm screening.

In this review, as in others supporting surveillance, aneurysm-related mortality was a relatively infrequent event. However, we know that despite operative repair preventing rupture, our older patients continue to die of other advanced conditions. In this series, we noted 21 cardiac and 10 cancer deaths within 3 years of AAA repair; therefore, the question for considering earlier AAA intervention is an important one. We did not perform a subset analysis of aneurysm morphology to determine if smaller aneurysms were more amenable to endovascular repair. Instead, we followed the size and growth parameters of the pathway to determine final operative options. Thus, I feel this review does little to support the concept of inviting earlier aneurysm repair.