Appropriateness Revascularization Criteria Validated in Real-World Study

October 11, 2012

October 11, 2012 (Toronto, Ontario)— Coronary revascularization is both overused in patients without appropriate indications and underused in those with appropriate indications, according to the results of a new Canadian study [1].

The study did find some positive results, though. It showed that when revascularization was performed in line with the recently created appropriateness guidelines, it was associated with reduced adverse outcomes compared with patients not undergoing revascularization. But in patients without an appropriate indication according to the criteria, no such reduction was seen with revascularization procedures.

Lead author of the study, Dr Dennis Ko (Institute for Clinical Evaluative Sciences, Toronto, ON), commented to heartwire : "These appropriateness criteria were formulated mainly on the basis of expert opinion. They haven't been proven before. But our study is a real-world validation. It shows that if the criteria are followed, revascularization will bring about better outcomes. This is direct evidence that the appropriateness criteria can be applied in clinical practice to improve health care."

For the study, published online on October 10, 2012 in the Journal of the American College of Cardiology, Ko et al studied 1625 patients with stable coronary artery disease who had undergone cardiac catheterization in Ontario between 2006 and 2007. The appropriateness for coronary revascularization was retrospectively adjudicated using the new appropriate-use criteria, and clinical outcomes between coronary revascularization and medical treatment without revascularization were compared both in patients deemed appropriate and inappropriate for the procedure.

Results showed that PCI or CABG was performed in only 69% of patients who had an appropriate indication for coronary revascularization. In these "appropriate" patients, coronary revascularization was associated with a lower adjusted hazard of death or ACS at three years compared with medical therapy.

The rate of coronary revascularization was 54% in the uncertain category and 45% in the inappropriate category. There was no significant difference in death or ACS between coronary revascularization and no revascularization in the uncertain or inappropriate categories.

Hazard Ratio for Death or ACS Associated With Revascularization According to "Appropriateness" Indication

Indication based on appropriateness criteria HR (95% CI)
Appropriate 0.61 (0.42–0.88)
Uncertain 0.57 (0.28–1.16)
Inappropriate 0.99 (0.48–2.02)

Ko added: "In the overall population, we found that 61% of revascularizations were appropriate, 20% were uncertain, and 19% were inappropriate. So there are a significant proportion of uncertain/inappropriate procedures."

He noted that there has also been a US study looking at this issue with broadly similar results. "But in the US, there are about double the amount of procedures done on a population level than in Canada, so the absolute numbers of inappropriate procedures are much larger. The fee-for-service structure of the US healthcare system is a definite contributory factor to this."

The researchers comment in the paper that "although proliferation of cardiac technology has been the focus of recent healthcare reforms, underutilization of beneficial therapy continues to exist for a significant proportion of patients in clinical practice." They add that the majority of appropriate patients had no documented reasons to explain the reason that coronary revascularization was not performed, and many of these patients had higher risk characteristics and more frequent comorbidities.

They suggest that their findings of better outcomes in "appropriate" patients given revascularization may be surprising, given the results of the COURAGE study, which showed no difference in clinical outcomes between PCI and medical therapy in stable CAD patients. But they point out that many patients in the current study may have been excluded from COURAGE, as they had substantial ischemic burden, and 40% received CABG, which was not a treatment option for the COURAGE patients.