Does coronary calcium score zero reliably rule out coronary artery disease in low-to-intermediate risk patients? A...

Objective was to assess if coronary calcium score (CCS) zero (<1.0AU) reliably rules out coronary artery disease (CAD) by coronary CTA; and if a difference between CCS zero and ultralow CCS (0.1-0.9AU) exists.

6439 low-to-intermediate ASCVD-risk patients (57.9 ± 11.1 years; 44.4% females) who underwent CTA and CCS were enrolled. Coronary CTAs were evaluated for: (1) stenosis severity (CADRADS: <25%, 25-49%, 50-69%, 70-99%, and 100%), (2) mixed-plaque burden, and (3) high-risk-plaque-(HRP)-criteria. Primary endpoints were all-cause and cardiovascular (CV) mortality, secondary endpoint MACE.

Overall 1451 (22.5%) had CCS<1.0 AU. Among them, 1289 had CCS zero and 162 ultralow CCS (0.1-0.9AU). In CCS zero patients, 25.9% had CAD, 5.1% > 50% and 20.8% less than 50% stenosis, 6.8% had HRP with min 2 criteria, respectively. LAP<30HU, LAP<60HU, Napkin-Ring-Sign, Spotty calcification and PR were found in 1.3%, 3.7%, 2.8%, 2.3% and 8.2%. CAD prevalence was with 87.7% markedly higher in the ultralow CCS (p < 0.001) group, >50% stenosis (16.6%), total plaque burden (p < 0.001) and HRP-criteria rates were higher (up to 19.1%) (p < 0.001, respectively).All-cause mortality was similar (2.7% and 1.9%) in CCS 0 and ultralow patients (mean follow-up 6.6 ± 4.2 years). Composite MACE (n = 7, 0.48%) was higher than CV-mortality (n = 1, 0.06%, p = 0.038, OR 1.08-1.6). More HRP were found on 128-slice-dual-source-CTA compared to 64-slice (p < 0.001). There were no differences in CTA findings between patients with and without chest pain, but more females were symptomatic.

Early signs of CAD on CTA are frequent in CCS zero and even present in the majority of ultralow CCS (0.1-0.9AU) patients, who should not be downgraded to CCS zero patients. High-risk plaque and >50% stenosis rate is low but not negligible; and MACE rate very low.