Selective Use of DES Saves Millions of Dollars a Year

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When drug-eluting stent (DES) usage plummeted by almost 25% following a US Food and Drug Administration (FDA) advisory statement in 2007 over safety concerns, the resulting shift in practice ended up saving the health care system roughly $400 million annually. According to an analysis published online August 15, 2011, ahead of print in Circulation, the cost savings were accompanied by virtually no worsening of patient outcomes.

Researchers led by David J. Cohen, MD, MSc, of Saint Luke’s Mid America Heart Institute (Kansas City, MO), looked at clinical outcomes and cardiovascular-specific costs associated with DES use in 10,144 patients undergoing PCI at 55 US centers in the national EVENT (Evaluation of Drug Eluting Stents and Ischemic Events) registry from 2004 through 2007. Since the FDA advisory was issued in January 2007, outcomes and costs were compared between 2 time periods: 2004 to 2006, and 2007.

During the “liberal era” of DES usage from 2004 to 2006, 7,587 DES were implanted, translating to 92% of PCI procedures. This rate fell to 68% (n = 2,557 DES) in 2007, the beginning of the “selective era” (P < 0.001). Between the 2 cohorts, there were no differences in angiographic success or procedural complications. There also were no differences in prescription of recommended pharmacological therapy, while mean duration of clopidogrel use was 10.6 ± 2.9 months during the liberal era and 11.0 ± 2.3 months during 2007.

DES Use Gets Selective

In terms of the criteria used during the selective period, DES were more likely to be used than BMS in 2007 in younger patients (adjusted OR 0.99 for age per year; 95% CI 0.98-1.00; P = 0.03) and those with stable disease (adjusted OR 1.45; 95% CI 1.18-1.78; P < 0.001). Likewise, DES were more likely to be used in patients with left main or LAD lesions, bifurcations, in-stent restenosis, longer lesions, and smaller vessels, as well as patients receiving warfarin at the time of index PCI.

“What we [found] is that the patients who received drug-eluting stents in the later period were preferentially being selected for characteristics that we know are associated with a higher risk of restenosis,” Dr. Cohen told TCTMD in a telephone interview. “So all those factors were enhanced compared with the earlier period when DES were being used in almost everybody.”

Almost No Change in Outcomes

One-year clinical outcomes were no different between the 2 cohorts, with the exception of TLR, which increased in the selective era (table 1).

Table 1. Clinical Outcomes 1 Year Post Discharge After DES Implantation

Over the same time periods, overall cardiovascular costs per patient decreased by $401 ($14,742 vs. $15,143; P = 0.004), driven primary by reduced stent usage in the selective era (table 2).

Table 2. Mean CV Costs Per Patient: Initial PCI and 1-Year Follow-up

^a Stent costs are incorporated into the index hospitalization costs.

 

At almost 1 million PCI procedures per year in the United States, the more selective DES era was estimated as resulting in a roughly $400 million cost savings to the US health care system compared with the previous era.

In a cost-effectiveness analysis, the risk adjusted cost effectiveness ratio for the liberal vs. selective DES era was:

• $16,000 per each TLR avoided
• $27,000 per each repeat revascularization avoided
• $433,000 for each quality-adjusted life year (QALY) gained

The authors note that within the US health care system, cost effectiveness ratios of under $10,000 for repeat revascularizations avoided and under $50,000 to $100,000 per QALY gained are considered worthwhile economically, suggesting that “although clinical outcomes are marginally better with unrestricted DES use, this approach represents a relatively inefficient use of health care resources relative to several common benchmarks for cost-effective care.”

According to Dr. Cohen, there are 2 equally valid ways of interpreting the findings. “What we conclude is that doctors can be more selective in using drug-eluting stents and save the health care system a whole lot of money with very little downside in terms of clinical outcomes,” he said. “Looking in the other direction, we conclude that using drug-eluting stents in virtually all patients [undergoing PCI] as compared with a more selective strategy is spending a lot of money and getting very little additional for it. Both statements are actually correct.”

In a telephone interview with TCTMD, Peter W. Groeneveld, MD, MS, of the University of Pennsylvania School of Medicine (Philadelphia, PA), agreed, focusing on the lack of difference between the 2 eras in meaningful outcomes. “From a patient perspective, all you really care about is if you have to go back to the hospital, so it’s really about repeat revascularizations, and that difference wasn’t even statistically significant,” he said. “There was a significant difference in TLR, but if I’m a patient sitting on a table, I don’t care if they’re fixing a target lesion or something else, it’s all the same.”

We Did Good

Dr. Groeneveld was quick to point out that selective use of DES does not necessarily equal optimal use. “It’s better than it was,” he said. “But it’s not clear that there’s not even more savings that could be wrung out of the system if people were compelled to use drug-eluting stents in an even more evidence-based fashion. All we know is that it’s better in terms of efficiency than it was before. We don’t know if this is the maximal efficiency.”

Dr. Cohen agreed that the study was not an attempt to define optimal DES usage. “Our studies that we’ve done would suggest that DES when used in higher-risk populations are cost effective,” he said. “But this study is a limited look. It’s really looking at this natural experiment and asking: Did we do good? And the answer is, I think we did.”

Back to the Future

Unfortunately, the study results are somewhat beside the point in the larger picture, according to Dr. Groeneveld. “Figuring out that we just wasted half a billion dollars is not nearly as good as trying to not waste the money down the road,” he said. “We have to figure out how to do this in advance.”

This is especially true since some studies have shown that DES usage since the low of 2007 has steadily crept back up in US practice to as high as 76% as of 2009. “The challenge is not just saying we’re better off than 2005,” Dr. Groeneveld said. “The real question is, how do we make the use of this technology more optimal given that we can be pretty sure it’s not being used optimally now?”

“It’s hard to say because we don’t have data from this study that goes beyond 2007,” Dr. Cohen said. “What we can say is that unselected use of DES is relatively inefficient and we can be more efficient as we’ve shown. If we’ve gone back up to the same level of 92%, it’s very likely we’re putting a lot of drug-eluting stents into patients who are deriving very little benefit.”

 

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Source:
Venkitachalam L, Lei Y, Stolker JM, et al. Clinical and economic outcomes of liberal versus selective drug-eluting stent use: Insights from temporal analysis of the multicenter Evaluation of Drug Eluting Stents and Ischemic Events (EVENT) registry. Circulation. 2011;Epub ahead of print.

 

Disclosures:

• The EVENT registry was funded by grants from Millennium Pharmaceuticals and Schering Plough.
• Dr. Cohen reports receiving grant support from Abbott Vascular, Boston Scientific, Edwards Lifesciences, Eli Lilly/Daiichi-Sankyo, and Merck/Schering Plough, and serving as a consultant to Cordis, Eli Lilly, Medtronic, Merck/Schering Plough, and The Medicines Company.
• Dr. Groeneveld reports no relevant conflicts of interest.

 

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