Cost-Effectiveness of Angioplasty vs. Surgery
ABSTRACT & COMMENTARY
Patients were included in BARI if they had angina or objective evidence of ischemia, 50% or greater stenosis in two or more coronary arteries, and no prior revascularization. Functional status was measured on the Duke Activity Status Index of 12 items representing common activities of daily living with a total score ranging from 0.0 to 58.2, where the higher number represents more activity. Mean baseline scores of 21.6 and 20.0 in the angioplasty and bypass surgery groups, respectively, were not different, but after one year the surgery patients improved by 7.0 units vs. 4.4 for the angioplasty group (P = 0.02). This difference persisted for three years.
Emotional health was measured by the Rand Mental Health Inventory (MHI), which scores five items on a total score of 0-100, with higher numbers reflecting better mental health. At baseline, the MHI was not different between groups (72.7 vs 73.0); scores increased after revascularization but were not different between the two groups over the follow-up.
The percentage of patients employed at baseline was 40% in the angioplasty group and 46% in the bypass group. The angioplasty patients returned to work faster than the bypass patients (6 vs 11 weeks; P < 0.001). However, at one year, there was no significant difference between groups, and only 75% of those initially employed had returned to work.
The initial cost of angioplasty was two-thirds that of surgery ($21,113 vs $32,347; P < 0.001), but by five years, the difference had narrowed to 5%, or $2664. The five-year cost of angioplasty was less than that of surgery for patients with two-vessel disease ($52,930 vs $58,498; P < 0.05) but not for patients with three-vessel disease ($60,918 vs $59,430). Surgery was particularly cost-effective for diabetics because of their improved survival as compared to survival after treatment with angioplasty.
The authors conclude that in patients with multivessel disease, coronary artery bypass surgery has better quality of life for three years after the initial morbidity of surgery as compared to angioplasty, but that angioplasty has lower costs over five years in patients with two-vessel disease. (Hlatky MA, et al. N Engl J Med 1997;336:92-99.)
COMMENT BY MICHAEL H. CRAWFORD, MD
Like the reported mortality and morbidity results of the BARI trial itself, this cost effectiveness analysis shows very small differences between the two types of treatment; however, some of the analyses did achieve statistical significance.Angioplasty has an immediate cost advantage as compared to surgery, but this advantage is progressively lost over time due to the increased need for repeat hospitalizations and revascularization procedures in the group initially randomized to angioplasty. However, in this study, surgery was still somewhat more expensive than angioplasty at the end of five years, with the exception of patients with three-vessel disease, in whom it was almost equal. This was corroborated by a separate analysis of the determinants of costs in the angioplasty group, which found that the number of vessels diseased was directly proportional to costs. Thus, the more vessels that are diseased, the more opportunities for repeat revascularization and hence increased costs—these results should not be surprising. Despite the slightly higher costs of surgery, the cost per year of life added was only $26,117, well within other commonly employed treatments in medicine.
One problem with this analysis of surgical results is that we know that at around 5-8 years there is considerable graft attrition, especially in vein grafts. If in the next few years the need for surgical revascularization increases, the initial cost advantage of surgery in patients with three-vessel disease may be eliminated. However, angioplasty patients may progress to the point that they need surgery in this eight-year time frame as well. So, hopefully, further follow-up of these BARI subjects will be performed.
A disappointing feature of this study is the employment figures. Of those initially employed, 75% returned to work after one year, 50% after three years, and only 45% were employed after five years. This result was not different between the two groups. It is disappointing that revascularization, which has been shown to improve morbidity and mortality in patients with coronary artery disease, does not seem to improve employability. Even angioplasty, with its rapid recovery and low cost, is not more successful at returning patients to work. Of course, the mean age of the patients was approximately 62 years in both groups. Thus, many patients were probably eligible for Medicare and other retirement benefits, and their illness may have been a stimulus to retire.
The enhanced cost effectiveness of surgery in the diabetic patients was understandable, given the fact that the original BARI analysis showed increased survival in patients with multivessel disease and diabetes randomized to the surgical arm. What was less predictable was the excellent performance of surgery in patients with three-vessel disease. Although angioplasties seem to be highly successful for patients with two-vessel disease, it was noted by the authors that the variability in cost was much greater in the angioplasty patients than in the surgery patients.
This means that some angioplasty patients had tremendous increases in costs, some going over $100,000 per added year of life. This reflects the unpredictable nature of restenosis and its attendant costs. Another interesting feature was that the improvement in the Duke activity score was greater in men than in women. The reason for this difference is unclear, and the authors did not speculate on potential causes.
The implications of this study for those of us taking care of patients is that for diabetics and patients with three-vessel disease, surgery should be seriously considered given the excellent morbidity and mortality, the cost-effectiveness benefit in diabetics, and the improved quality of life over three years in the surgery patients as compared to the angioplasty patients with almost identical five-year costs. For non-diabetic patients with two vessel disease, angioplasty would be favored because of lower cost over five years.
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