While substituting bivalirudin (Angiomax, The Medicines Company) for unfractionated heparin may be reasonably cost effective for patients at a high risk for bleeding after PCI, it is not cost effective for the majority of patients (90 percent or greater) at a low or moderate risk for bleeding, according to a study published in the July edition of Circulation: Cardiovascular Quality and Outcomes.
“Although bivalirudin has been shown to be a safe and effective adjunctive antihrombin during PCI, its high cost may prevent its use in all eligible patients,” the authors wrote.
To assess the economic impact of bivalirudin versus heparin and the threshold of procedural bleeding risk at which the drug is cost effective, Amit P. Amin, MD, of Saint Luke’s Mid America Heart Institute in Kansas City, Mo., and colleagues used the National Cardiovascular Data Registry (NCDR) CathPCI Registry to identify 81,628 PCI patients administered only heparin between 2004 to 2006 at 178 centers.
The researchers used a decision-analytic model to assess the cost effectiveness of bivalirudin to PCI patients and administered patient’s bivalirudin therapy if their predicated risk was above the treatment thresholds.
Amin et al estimated the costs associated with bleeding incidence by using data from the Mid America Heart Institute and FDA approved dosing regimens.
The researchers found that the average predicted risk of bleeding was 2.18 percent and the estimated average bivalirudin dose was 138.2 mg or 1.1 vials. The associated costs surrounding bivalirudin use was estimated to be $637. The costs associated with heparin were not included in the study.
The estimated risk of major bleeding would decrease from 2.18 percent to 1.44 percent when bivalirudin was used in place of heparin. However, the cost per patient association with this substitution would rise from $19,125 to $19,696—a $571 difference per patients.
“As the threshold probability of a major bleed above which patients are treated with bivalirudin increased (fewer patients are treated with bivalirudin), the risk of major bleeding in the treated population increased, and the cost-effectiveness ratios became more favorable,” the authors wrote.
Hypothetically, the authors estimated that in a center performing 1,000 PCIs per year using heparin alone, assuming a rate of 22 bleeds per year (2.18 percent), bivalirudin use would prevent seven to eight major bleeds at a cost of approximately $571,000 ($571 per patient).
To estimate the average cost per major bleed prevented when treating all patients versus no patients, the researchers divided the difference in average costs of the two strategies by the difference in major bleeding rates ($19,696-$19,125, 2.18-1.44 percent). The cost per major bleed prevented was $76,981.
The researchers also estimated projected life expectancy for PCI patients to be 11.1 years with a major bleeding event and 11.3 years for patients who did not undergo a major bleeding event—patients who experienced a major bleed saw a reduction of 0.23 year of life.
“A willingness-to pay threshold of $50,000 per life-year gained, changing the threshold for treatment from 9 percent to 8 percent would be economically attractive, whereas changing the treatment threshold from 6 percent to 5 percent would be economical at a willingness-to-pay threshold $100,000 per life-year gained,” the authors wrote.
Thus, why it may be cost effective to treat PCI patients at high risk for bleeding complications with bivalirudin rather than heparin, it is not cost effective for those patients at a low and intermediate risk of major bleeding.
“As the level of risk rises, therapy to decrease events can become more cost effective,” the authors concluded. “From a societal or policy standpoint, studies such as this may help in the development of informed guidelines for the use of expensive therapies.”