Coronary artery calcium score of zero does not rule out obstructive CAD in young adults

Young adults are more likely to have non-calcified coronary plaques. Purpose to assess the predictive value of a zero-coronary artery calcium (CAC) score in young adults and to determine which clinical characteristics are associated with obstructive coronary heart disease.

6775 patients were prospectively entered a registry. They all had a CAC. Mean age 63 +/- 18 years. 56.2 % males. 3525 patients underwent coronary CT angiography (CCTA). 3250 patients underwent single photon emission tomography (SPECT). SPECT patients were mainly outpatients. CCTA patients also were almost exclusively outpatients. Thus, the population was generally a low-risk population.

Among the CCTA patients, 1888 had a 0 CAC score. 175/1888 (9 %) had less than 70 % stenosis, while 41/1888 (2.2 %) had ≥70 % stenosis. Patients with ≥70 % stenosis: were younger 45 ± 12 yr versus 59 ± 11 yr, p < 0.001, predominantly males (51.2 % versus 38.8 % p < 0.001), had a slightly greater prevalence of family history of CAD (58.5 % vs 57.9 % p = 0.04), smoking history (68.3 % VS.44.6 % p < 0.001), hypertension (61 % versus 39.2 % p = 0.004), dyslipidemia (56.1 % versus 36.2 % p < 0.001), and obesity (70.7 % VS 11.7 % p < 0.001). 3250 patients had CAC and SPECT. Of these, 1161 had a zero CAC score. Of these 42 patients had significant ischemia >10 % of LV, Patients with ischemia >10 % of LV mass, and they were younger 44 ± 10 yr versus 60 ± 12 yr, p < 0.001, had a slightly greater prevalence of family history of CAD 61 % versus 57 % p = 0.07, smoking history (64.3 % versus 48.5 % p = 0.045), hypertension (69 % versus 45.5 % p = 0.003), obesity 19 % versus 11.7 %, and diabetes (35.7 % versus 14.5 % p < 0.001).

A zero CAC does not rule out significant CAD in young adults with chest pain with CAD risk factors. These patients may need further investigations.