CABG More Cost-Effective in Patients with Diabetes, Multivessel Disease Over Long Term

Despite higher initial costs, coronary artery bypass graft (CABG) surgery is a highly cost-effective revascularization strategy compared with percutaneous coronary intervention (PCI) with drug-eluting stents (DES) for patients with diabetes and multivessel disease, according to a study published online December 31, 2012, ahead of print in Circulation.

In the main FREEDOM trial, 1,855 patients with diabetes and multivessel disease were randomized to CABG or PCI with DES and followed for 47 months. The results (Farkouh ME, et al. N Engl J Med. 2012:Epub ahead of print) showed that CABG was associated with lower rates of death, MI, or stroke.

In a companion study, David J. Cohen, MD, MSc, of Saint Luke’s Mid America Heart Institute (Kansas City, MO), and colleagues looked at the costs and long-term cost-effectiveness of the 2 strategies, measuring quality-adjusted life years (QALY) gained. The results were originally presented in November 2012 at the American Heart Association Scientific Sessions in Los Angeles, CA.

The total index procedure cost was higher for PCI ($13,014 vs. $9,739), due in part to the cost of DES (an average of 4.1 stents per patient at an estimated cost of $1,500 per device). However, because of higher physician fees, longer recovery times, and other ancillary costs, the overall index hospitalization cost was higher with CABG ($34,467 vs. $25,845; P < 0.001).

CABG Eventually Comes Out Ahead

Over time, though, the gap in costs narrowed due to more repeat revascularizations (6.8 per 100 person-years vs. 3.3; P < 0.001) and CV hospitalizations (17.2 per 100 person-years vs. 10.8; P < 0.001) with PCI vs. CABG. The difference in costs narrowed from $7,878 at 1 year to $3,641 at 5 years. This translated to a switch from a gain of 0.033 QALYs with PCI at 1 year to a gain of 0.031 QALYs with CABG at 5 years at a cost of $116,699 per QALY gained with CABG.

Using an analysis model projecting the post-trial costs and QALYs from FREEDOM, the researchers demonstrated a lifetime difference in cost of $5,392 favoring PCI, with 0.663 QALYs gained with CABG. This translated to an incremental cost-effectiveness ratio of $8,132 per QALY gained with CABG, well under the generally accepted threshold of $50,000.

These results remained consistent in a subanalysis by Syntax score (table 1) and multivessel disease (table 2).

Table 1. Cost-Effectiveness of CABG vs. PCI by Syntax Score

Table 2. Cost-Effectiveness of CABG vs. PCI by Multivessel Disease

 
Reason to Strengthen Current Guidelines

Once the clinical results of the FREEDOM trial were finalized, Dr. Cohen told TCTMD in a telephone interview, he was not surprised by anything in the cost analysis. “I do think that the extent to which small differences in survival during the trial translated into large gains in life expectancy may seem sort of counterintuitive to people who aren’t used to these sorts of analyses,” he added.

The results highlight the fact that “our guidelines with respect to revascularization in patients with multivessel disease and diabetes are spot on,” Dr. Cohen observed. “Not only are the clinical outcomes substantially better with bypass surgery compared to drug-eluting stents but the economics are also quite favorable.” He added that although CABG was “not cost-saving, it was almost cost-saving in this analysis, and clearly cost-effective by any reasonable standards.”

If any changes to the guidelines need to me made, Dr. Cohen continued, perhaps they should be strengthened, because several studies have now come to similar conclusions.

Going forward, it will be important to answer the remaining questions about treatment in patients with 2-vessel disease since most of the patients in FREEDOM had 3-vessel disease, Dr. Cohen noted. The value of hybrid revascularization, or “combining surgery for the LAD and PCI with stents for other vessels, in diabetic patients” should also be analyzed.

But “the big question is of course how to improve outcomes regardless of which type of revascularization is performed. . . . We need therapies that modify the natural history of diabetes,” he said.

Finally, “there is still some room for individualizing therapy and that needs to be better explored,” Dr. Cohen concluded, adding that for some patients, waiting 4 to 5 years for a survival benefit might not be the most important consideration.

PCI Has Something to Prove

In a telephone interview with TCTMD, Ajay J. Kirtane, MD, SM, of Columbia University Medical Center (New York, NY), said the analysis will be difficult to completely extrapolate to the US population because the trial enrolled patients inside and outside the country.

“If you look at the utility, or the way that patients felt, PCI and CABG were remarkably similar out to 4 years. To me, that suggests that that’s a good thing for patients who would choose PCI in terms of how they feel,” Dr. Kirtane said. “The problem that these patients face—and that was brought out by the main FREEDOM results—is that the differences in myocardial infarction and mortality over the long term are what really end up favoring CABG over PCI. If patients feel better with PCI early and then feel the same late, and if CABG is more expensive than PCI, then early on it would appear that PCI would do well. But these late events that accrue are what make CABG more favorable.”

As an interventionalist, this is an issue that gives Dr. Kirtane pause. Additionally, it “suggests that more judicious use of newer-generation stent platforms and/or for instance FFR-guided PCI might have an ability to further improve our outcomes,” he said.

The key, he added, will be to prove that PCI can be as good as CABG for these patients. “I think the field has advanced sufficiently between when this study was [done] and now to favor CABG as a whole but to suggest that for appropriately selected patients and for patients who choose not to undergo a far more invasive and morbid procedure, [namely,] CABG, PCI could be an option,” Dr. Kirtane said.

 

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Source:
Magnuson EA, Farkouh ME, Fuster V, et al. Cost-effectiveness of percutaneous coronary intervention with drug eluting stents versus bypass surgery for patients with diabetes and multivessel coronary artery disease: Results from the FREEDOM trial. Circulation. 2012;Epub ahead of print.

 

 

Related Stories:

• Pair of Studies Look at Cost Effectiveness of PCI in Different Populations
• FREEDOM: CABG Superior to PCI in Diabetic Patients with Multivessel Disease
• SYNTAX Left Main: PCI Provides Similar Angina Relief to CABG at Lower Cost