Precision CAD Testing Shows 70% Cut in Composite Risk at 1 Year

CHICAGO — A stepwise care pathway was associated with a substantial reduction in the number of invasive tests performed and a major improvement in outcomes, relative to usual management, in patients suspected of coronary artery disease (CAD), according to 1-year results of the multinational, randomized PRECISE trial.

The care pathway is appropriate for patients with nonacute chest pain or equivalent complaints that have raised suspicion of CAD, and it is extremely simple, according to the description from the principal investigator, Pamela S. Douglas, MD, given in her presentation at the annual scientific sessions of the American Heart Association.

Unlike the highly complex diagnostic algorithms shunting suspected CAD patients to the vast array of potential evaluations, the newly tested protocol, characterized as a “precision strategy,” divides patients into those who are immediate candidates for invasive testing and those who are not. The discriminator is the PROMISE minimal risk assessment score, a tool already validated.

Those deemed candidates for testing on the basis of an elevated score undergo computed coronary CT angiography (cCTA). In those who are not, testing is deferred.

Strategy Is Simple but Effective

Although simple, this pathway is highly effective, judging by the results of the PRECISE trial, which tested the strategy in 2,103 patients at 65 sites in North America and Europe. The primary outcome was a composite of major adverse cardiovascular events (MACE) that included death, nonfatal MI, and catheterization without observed CAD.

After a median follow-up of 11.8 months, the primary MACE endpoint was reached in about 11.3% of those in the usual-care group, which was more than twofold higher than the 4.2% in the precision strategy group. The unadjusted risk reduction was 65% but rose to more than 70% (hazard ratio, 0.29; P < .001) after adjustment for gender and baseline characteristics.

In the arm randomized to the precision strategy, 16% were characterized as low risk and received no further testing. Almost all the others underwent cCTA alone (48%) or cCTA with fractional flow reserve (FFR) (31%). Stress echocardiography, treadmill electrocardiography, and other functional studies were performed in the small proportion of remaining patients.

cCTA Performed in Just 15% of Usual Care

In the usual-care arm, cCTA with or without FFR was only performed in 15%. More than 80% of patients underwent evaluations with one or more of an array of functional tests. For example, one-third were evaluated with single photon emission CT/PET and nearly as many underwent stress echocardiography testing. Only 7% in usual care underwent no testing after referral.

Within the MACE composite endpoint, almost all the relative benefit in the precision strategy arm was derived from the endpoint of angiography performed without evidence of obstructive CAD (2.6% vs. 10.2%). Rates of all-cause mortality and MI were not significantly different.

Important for the safety and utility of the precision strategy, there “were no deaths or MI events among those assigned deferred testing” in that experimental arm, according to Douglas, professor of research in cardiovascular diseases at Duke University, Durham, N.C.

Instead, those in the precision strategy arm were far less likely to undergo catheterization without finding CAD (20% vs. 60%) and far less likely to undergo catheterization without revascularization (28% vs. 70%).

In addition, the group randomized to the precision strategy were more likely to be placed on risk reducing therapies following testing. Although the higher proportion of patients placed on antihypertensive therapy did not reach statistical significance (P = .1), the increased proportions placed on lipid therapy (P < .001) and antiplatelet therapy (P < .001) did.

Citing a study in JAMA Cardiology that found that more than 25% of patients presenting with stable chest pain have normal coronary arteries, Douglas said that the precision strategy as shown in the PRECISE trial addresses several agreed-upon goals in guidelines from the AHA, the European Society of Cardiology and the U.K.’s National Institute for Health and Care Excellence. These goals include reducing unnecessary testing by risk stratification, improving diagnostic yield of the testing that is performed, and avoiding the costs and complications of unneeded invasive testing.

New Protocol Called Preferred Approach

On the basis of these results, Douglas called the precision strategy “a preferred approach in evaluating patients with stable symptoms and suspected coronary disease.”

Julie Indik, MD, PhD, a professor of medicine at the University of Arizona, Tuscon, said that application of this approach in routine care could have “a major impact on care” by avoiding unnecessary tests with no apparent adverse effect on outcomes.

Although not demonstrated in this study, Indik suggested that the large number of patients tested for CAD each year – she estimated 4 million visits – means that less testing is likely to have a major impact on the costs of care, and she praised “the practical, efficient” approach of the precision strategy.

Ron Blankstein, MD, director of cardiac computed tomography, Brigham and Women’s Hospital, Boston, also said these data “have both economic and safety implications.” As an AHA-invited discussant of this study, he emphasized that this is a strategy that should only be applied to lower risk patients with no prior history of CAD, but, in this group, he believes these data “will inform future guidelines.”

Douglas declined to speculate on whether the precision strategy will be incorporated into future guidelines, but she did say that the PRECISE data demonstrate that this approach improves quality of care.

In an interview, Douglas suggested that this care pathway could provide a basis on which to demonstrate improved outcomes with more efficient use of resources, a common definition of quality care delivery.

Douglas reported financial relationships with Caption Health, Kowa, and Heartflow, which provided funding for the PRECISE trial. Indik reported no potential conflicts of interest. Blankstein reported financial relationships with Amgen, Caristo Diagnostics, and Novartis.

This article originally appeared on, part of the Medscape Professional Network.

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