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Study Assesses Clinical and Economic Implications of DES
Implanting bare-metal stents (BMS) rather than drug-eluting stents (DES) in patients at low risk of restenosis has the potential for significant cost savings and may lead to fewer additional target-vessel revascularization (TVR) procedures, according to the results of a retrospective study from the National Cardiovascular Data Registry (NCDR®) CathPCI Registry® reported online in the Archives of Internal Medicine [doi:10.1001/archinternmed.2012.3093].
To determine current patterns of DES use as a function of TVR risk and the possible clinical and economic implications of more tailored DES use, the researchers analyzed records from >1.5 million percutaneous coronary intervention (PCI) procedures in the NCDR CathPCI Registry from January 2004 through September 2010. Using a validated prediction model developed from the Massachusetts Data Analysis (MassDAC) database, the researchers estimated the 1-year risk of a patient who had received a BMS needing a TVR. They also examined the association between TVR risk and DES use and the cost effectiveness of lower DES use in low-TVR-risk patients (50% less DES use among patients with <10% TVR risk), compared with existing DES use.
A total of 1,506,758 PCI admissions met the inclusion criteria. Of these, 648,292 patients were predicted to be in the low-TVR-risk group (43%), 659,838 in the moderate-TVR-risk group (43.8%), and 198,628 in the high-TVR-risk group (13.2%). Patients with a high-predicted TVR risk were more likely to be older and male and have diabetes, chronic kidney disease, and prior PCI.
Among the 2715 physicians performing 415,115 PCI procedures (at least >75% procedures per year), the researchers found a marked variation in how often DES was used for their patients, ranging from 2% of their cases to 100% of their cases. Use of DES was high across all predicted TVR risk categories (73.3% in TVR risk <10%; 78% in TVR risk 10%-20%; and 83,2% in TVR risk >20%) with a modest relationship between TVR risk and DES use (relative risk, 1.005 per 1% increase in TVR risk; 95% confidence interval [CI], 1.005-1.006).
The researchers calculated the costs and benefits of using DES versus BMS in each procedure with a statistical model factoring in the cost of stents, the costs of repeated TVR procedures, and the cost of dual-antiplatelet therapy (DAPT). They assumed that patients who had elective PCI procedures would be on DAPT therapy for 1 month after BMS and 12 months after DES. For patients receiving a stent for an acute coronary syndrome, the model assumed patients would be on DAPT for 1 year regardless of stent type used.
Based on the model, the researchers found that reducing DES use by 50% in low-TVR-risk patients was projected to lower US healthcare costs by $204,654,000 per year (95% CI, $189,899,520-$227,258,760), or $34,109 per 100 PCI performed, compared with current practices. The estimated savings occurred even after accounting for a modest estimated increase in repeated procedures due to TVR (absolute increase in TVR event rate, 0.5%; 95% CI, 0.49%-0.51%), which were estimated to cost $64,728,000.
The authors acknowledged the following study limitations: the discrimination of the model used to estimate predicted TVR risk was modest; the researchers did not have any assessment of patient preferences regarding stent type or willingness to accept the costs and risks of prolonged DAPT in exchange for a reduced risk of repeated procedures; and the MassDAC model has only been validated in Massachusetts, not in the entire NCDR CathPCI Registry.
In conclusion, the researchers stated, “Given the marked variation in physicians’ DES use, a strategy of lower DES use among patients at low risk of TVR could present an important opportunity to reduce healthcare expenditures while preserving the vast majority of their clinical benefits.”
