Importance: Guidelines recommend deferral of testing for symptomatic people with suspected coronary artery disease (CAD) and low pretest probability. To our knowledge, no randomized trial has prospectively evaluated such a strategy.
Objective: To assess process of care and health outcomes in people identified as minimal risk for CAD when testing is deferred.
Design, setting, and participants: This randomized, pragmatic effectiveness trial included prespecified subgroup analysis of the PRECISE trial at 65 North American and European sites. Participants identified as minimal risk by the validated PROMISE minimal risk score (PMRS) were included.
Intervention: Randomization to a precision strategy using the PMRS to assign those with minimal risk to deferred testing and others to coronary computed tomography angiography with selective computed tomography-derived fractional flow reserve, or to usual testing (stress testing or catheterization with PMRS masked). Randomization was stratified by PMRS risk.
Main outcome: Composite of all-cause death, nonfatal myocardial infarction (MI), or catheterization without obstructive CAD through 12 months.
Results: Among 2103 participants, 422 were identified as minimal risk (20%) and randomized to deferred testing (n = 214) or usual testing (n = 208). Mean age (SD) was 46 (8.6) years; 304 were women (72%). During follow-up, 138 of those randomized to deferred testing never had testing (64%), whereas 76 had a downstream test (36%) (at median [IQR] 48 [15-78] days) for worsening (30%), uncontrolled (10%), or new symptoms (6%), or changing clinician preference (19%) or participant preference (10%). Results were normal for 96% of these tests. The primary end point occurred in 2 deferred testing (0.9%) and 13 usual testing participants (6.3%) (hazard ratio, 0.15; 95% CI, 0.03-0.66; P = .01). No death or MI was observed in the deferred testing participants, while 1 noncardiovascular death and 1 MI occurred in the usual testing group. Two participants (0.9%) had catheterizations without obstructive CAD in the deferred testing group and 12 (5.8%) with usual testing (P = .02). At baseline, 70% of participants had frequent angina and there was similar reduction of frequent angina to less than 20% at 12 months in both groups.
Conclusion and relevance: In symptomatic participants with suspected CAD, identification of minimal risk by the PMRS guided a strategy of initially deferred testing. The strategy was safe with no observed adverse outcome events, fewer catheterizations without obstructive CAD, and similar symptom relief compared with usual testing.
Trial registration: ClinicalTrials.gov Identifier: NCT03702244.