Can You Safely Shift Lower Risk Patients to CCTA When Evaluating Suspected Stable CAD?
Results from the CONSERVE trial support the use of CCTA as a front-line diagnostic procedure in low-risk patients being evaluated for stable CAD.
For stable patients with suspected coronary artery disease (CAD), similar 1-year rates for major adverse cardiovascular events were seen for a selective referral strategy that used coronary computed tomographic angiography (CCTA) compared with a direct referral strategy that used invasive coronary angiography (ICA), according to a study published in JACC: Cardiovascular Imaging.
A substantial proportion of patients who are referred to ICA after presenting with the symptoms of coronary artery disease do not have an actionable obstructive stenosis, resulting in the expense and risk of an unneeded, invasive procedure.
In the multinational, randomized, controlled Coronary Computed Tomographic Angiography for Selective Cardiac Catheterization (CONSERVE, ClinicalTrials.gov Identifier: NCT01810198) open-label clinical trial of patients with suspected CAD, researchers compared outcomes using CCTA with ICA.
The primary study end point was noninferiority by a 1.33 multiplicative margin of major adverse cardiovascular event at 1-year median follow-up (composite of stroke, urgent and/or emergent coronary revascularization, myocardial infarction, blindly adjudicated death, unstable angina, or cardiac hospitalization).
Out of an initial total of 1664 patients, 1611 were randomized to either direct referral (n=808) or selective referral (n=823), and 1503 completed the study. Data were available for 719 of the direct referral strategy participants who underwent ICA, compared with 784 of the selective referral strategy participants who underwent CCTA.
At a median 1-year follow-up, the selective referral group met the 1.33 non-inferiority margin with a similar event rate between groups (4.6% vs 4.6%; hazard ratio, 0.99; 95% CI, 0.66–1.47; P =.026).
Only 23% of selective referral participants went on to ICA, compared with 100% of direct referral participants, 4% of whom when on to repeat ICA. Rates of percutaneous coronary intervention were lower among selective referral participants compared with direct referral (11% vs 15%; P <.001), as were rates of coronary revascularization (13% vs 18%; P =.007).
Rates of normal ICA, defined as no obstructive CAD, were 24.6% among selective referral participants compared with 61.1% of direct referral participants (P <.001)
Study investigators conclude, “Growing evidence supports that noninvasive anatomic testing by CCTA alone, as a gatekeeper procedure, may prove advantageous in promptly and accurately identifying candidates for downstream procedures. These data and similarly relevant findings from other randomized trials call for revisions to the current ischemic heart disease guidelines for the evaluation of patients with stable ischemic heart disease.”
Chang HJ, Lin FY, Gebow D, et al. Selective referral using CCTA versus direct referral for individuals referred to invasive coronary angiography for suspected CAD: A randomized, controlled, open-label trial [published online December 12, 2018]. JACC Cardiovasc Imaging. doi: 10.1016/j.jcmg.2018.09.018