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For most patients with 3-vessel or left main coronary artery disease, surgical revascularization is more efficacious than percutaneous coronary intervention (PCI), both clinically and economically, according to a cost-effectiveness analysis of long-term data from the SYNTAX trial. However, for those with less complex anatomy, PCI may be preferable on both grounds. 

The findings, which were originally presented at the Transcatheter Cardiovascular Therapeutics scientific symposium in October 2013, appeared online August 1, 2014, ahead of print in Circulation. 

Initial procedural costs were about $3,400 lower with CABG than PCI ($8,504 vs $11,919; P < .001), due to the costs of stents, catheters, and medications for PCI, while postprocedural hospital costs were greater for CABG ($19,511 vs $8,785), as were physician fees ($5,100 vs $2,315; P < .001 for both). As a result, total initial hospitalization costs were about $10,000 higher per patient in the CABG group ($33,190 vs $23,154; P < .001). 

Incremental Catch-up in PCI Cost Over 5 Years

During each year of follow-up, annual rates of repeat revascularization, diagnostic catheterization, and hospitalization and their associated costs were higher for PCI than CABG, as were costs for outpatient services and medications. Although rehabilitation costs were greater for CABG in the first year after the index procedure, they equalized over time. At 5 years, the difference in cumulative medical care costs between CABG and PCI narrowed to $5,619. 

Due to the longer recovery period for surgery, the weighted QoL was lower for CABG patients at 1 month, although the difference disappeared after 6 months. Cumulative quality-adjusted life-years were lower with CABG through 3 years of follow-up. However, by the end of 5 years, both life expectancy and quality-adjusted life expectancy were greater with CABG than with PCI. 

Lifetime Benefit Projection Decisive 

Based on the 5-year clinical results, the estimated mortality risk was a nonsignificant 20% lower for CABG vs PCI patients. When clinical and economic outcomes were projected beyond the trial period, CABG was associated with lifetime incremental costs of $5,081 compared with PCI, but gains in life expectancy and quality-adjusted life-years. This resulted in an incremental cost-effectiveness ratio (ICER)— a measure of societal willingness to pay—of $16,537/quality-adjusted life-years gained or $12,329/life-year gained. 

The findings were consistent across groups based on age, diabetes status, and location in vs outside the United States. However, for patients with less complex anatomy (Syntax score ≤ 22), PCI was projected to increase quality-adjusted life expectancy and reduce costs compared with CABG. For lower-risk patients and those with left main disease, PCI was projected to be an economically dominant strategy, whereas CABG appeared to be more attractive from a societal perspective for more complex disease (table 1). 

Table 1. Lifetime Cost-Effectiveness by Anatomic Subgroup

^a At a threshold of $50,000/quality-adjusted life-year gained. 

In sensitivity analyses, potential changes in stent cost only substantially affected therapy choice in patients with intermediate Syntax scores. 

A 5-Year About-Face

According to the authors, the current analysis contrasts with their earlier conclusion, based on 1-year SYNTAX data, that PCI was the economically dominant strategy. With longer follow-up, the cost advantage of PCI increased, largely due to a decline in DES cost and the availability of less-expensive generic clopidogrel, they note. More than countering that trend, however, the quality-adjusted life expectancy favoring PCI over CABG at 1 year was reversed with the 5-year data.

“These differences highlight the importance of basing policy decisions on clinical trials with sufficiently long follow-up to allow prognostically important benefits to emerge,” Dr. Cohen and colleagues say.

The big challenge with analyses of this nature is that data are available for only a certain period of time, after which the researchers have to extrapolate what happens with both costs and outcomes, Dhruv S. Kazi, MD, MSc, of the University of California, San Francisco (San Francisco, CA), told TCTMD in a telephone interview, adding that in general he agreed with the assumptions used in the long-term, base case model.

The overall conclusions regarding CABG’s cost-effectiveness are not surprising, Dr. Kazi said, because when a therapy carries a strong survival benefit, “the costs fall into place to support it.” He explained that “the incremental costs of an intervention are usually upfront, whereas the improved life expectancy at 5 years continues to accrue over the patient’s lifetime.”

On the other hand, the findings on the cost-effectiveness of PCI for patients with low Syntax scores are also predictable, he indicated. In this setting, interventionalists use fewer balloons and probably fewer stents, making PCI less expensive in terms of both procedural and hospitalization costs. And most important, CABG does not impart a mortality benefit. 

Dr. Kazi observed that while subgroup analyses provide only hypothesis-generating conclusions with regard to clinical practice, “when we make policy decisions, we have greater tolerance for uncertainty… I like to see ICERs under $50,000, but these sensitivity analyses are extraordinarily meaningful because they tell us what [factors] matter and what subgroups are particularly problematic.” 

Short-term Horizons Misleading 

Noting the reversal in cost-effectiveness conclusions between the analyses of 1-year vs 5-year outcomes, Dr. Kazi said that short-term horizons can be misleading and distort payers’ incentives. But, he predicted, that is likely to change. The majority of these patients will be covered by the same payer—Medicare—for the rest of their lifetime, and Medicare dollars are the same whether they are paid out at age 65 or 75, he explained. As a result, “the incentives on the part of the patient, provider, and payer are aligned to look at long-term outcomes, both clinical and economic,” he said.

“The primary study showed that particularly high-risk patients benefit substantially from CABG, both in terms of life expectancy and quality of life,” Dr. Kazi concluded. “The economic evaluation provides evidence that as a healthcare system we need to find better ways to channel these patients to CABG because it is the most cost-effective [strategy]. The economic analysis may provide payers and healthcare systems a voice at the table in the decision between PCI and CABG.”

Source:
Cohen DJ, Osnabrugge RL, Magnuson EA, et al. Cost-effectiveness of percutaneous coronary intervention with drug-eluting stents vs bypass surgery for patients with 3-vessel or left main coronary artery disease: final results from the SYNTAX trial. Circulation. 2014;Epub ahead of print.

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