Rationale and design of the Coronary Computed Tomographic Angiography for Selective Cardiac Catheterization: Relation to Cardiovascular Outcomes, Cost Effectiveness and Quality of Life (CONSERVE) trial.

Although coronary computed tomography angiography (CCTA) has shown promise as a "gatekeeper" to invasive coronary angiography (ICA) in longitudinal cohort studies, it remains unknown whether the strategy of selective ICA by initial performance of CCTA is either safe or effective when compared with a direct ICA strategy in patients with an American Heart Association (AHA)/American College of Cardiology (ACC) guideline-directed indication for ICA.

OBJECTIVES: The CONSERVE trial is a prospective randomized multicenter trial to determine the clinical effectiveness of "selective catheterization" vs "direct catheterization" strategies for stable patients with suspected but without known coronary artery disease, who meet AHA/ACC guideline indication for ICA.

METHODS: Patients being referred for clinically indicated nonemergent ICA with an AHA/ACC class II guideline indication for ICA will be randomized to either direct catheterization or selective catheterization strategy. Patients in the direct catheterization arm will proceed directly to ICA as planned, whereas patients in the select catheterization arm will undergo initial CCTA, followed by ICA at the discretion of the site physician. All CCTAs and ICAs will be interpreted on site. Follow-up testing and/or therapy after CCTA or ICA will be at the discretion of the site physician.

RESULTS: This trial will report a primary clinical end point of noninferiority rates of major adverse cardiac events, as defined by the composite of death, nonfatal myocardial infarction, unstable angina, stroke, urgent or emergent coronary revascularization, or cardiac hospitalization.

CONCLUSION: The CONSERVE trial will determine whether selective catheterization strategy, based on initial CCTA in patients being referred to ICA, is safe and effective.