The PROMISE Minimal Risk Score Improves Risk Classification of Symptomatic Patients With Suspected CAD.

Background: Guidelines for evaluating patients with suspected coronary artery disease (CAD) recommend pretest probability (PTP) estimation but provide no clear recommendations regarding diagnostic testing in patients with >5% to 15% risk of obstructive CAD. The diagnostic and prognostic value of PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) minimal risk score (PMRS) calculation in this patient group is unknown.

Objectives: This work aims to improve the evaluation of stable patients with suspected CAD by using the PMRS, which identifies patients at minimal risk of CAD and events in patients with >5% to 15% PTP of obstructive CAD.

Methods: Greater than 5% to 15% PTP patients from 2 large clinical trials were used for subcohort derivation: PROMISE (N = 10,003) and Dan-NICAD (Danish study of Non-Invasive Testing in Coronary Artery Disease) (N = 3,252). First, the PMRS cutoff associated with a prevalence of obstructive CAD ≤5% was determined in the >5% to 15% PTP PROMISE core lab computed tomographic angiography patients (discovery cohort: n = 2,191). This cutoff was validated for obstructive CAD in >5% to 15% PTP Dan-NICAD patients (CAD validation cohort: n = 1,386) and for prognostic impact on death and myocardial infarction in >5% to 15% PTP PROMISE non-core lab computed tomographic angiography patients (prognosis validation cohort: n = 2,753).

Results: In the discovery cohort, a CAD prevalence of ≤5% was found at a PMRS of ≥34%. In the CAD validation cohort, this cutoff down-classified 442 (31.9%) of >5% to 15% PTP patients into the low PTP group (CAD ≤5%); the prevalence of obstructive CAD in down-classified patients was 3.2% compared to 7.1% in non-down-classified patients. A PMRS ≥34% was nonsignificantly associated with a lower risk of myocardial infarction and death in the prognosis validation cohort (HR: 0.58 [95% CI: 0.29-1.18]; P = 0.13).

Conclusions: For evaluating patients with suspected CAD, a combined use of traditional PTP and the PMRS correctly down-classified one-third of >5% to 15% PTP patients into a group with very low prevalence of obstructive CAD and adverse events. The proposed strategy may improve risk stratification and help reduce unneeded diagnostic testing.