Obstructive coronary artery disease with low coronary artery calcium score on computed tomography angiography: who are these patients?

Abstract

Coronary artery calcium score (CACS) is directly associated with coronary atherosclerosis. However, some patients with obstructive coronary artery disease (CAD) have low CACS. This study aimed to describe the clinical profile of patients with obstructive CAD on coronary computed tomography angiography (CCTA) according to CACS level. This was a single-centre retrospective study that included patients who performed a CCTA from January 2017 to May 2021 and had obstructive CAD. Low CACS was considered if <100 AU. A combined endpoint including acute coronary syndrome, coronary revascularisation or cardiovascular death was analysed during the follow-up. From a total of 3436 CCTA exams, 298 (9%) patients were included. Low CACS was present in 105 (35%) patients. Patients with a low CACS were younger (58 [IQR 50-65] vs 63 [IQR 56-69] years, p<0.001), had a lower prevalence of hypertension (58% vs 72%, p=0.015) and diabetes (15% vs 25%, p= 0.043) and more frequent complaints of typical chest pain (34% vs 22%, p= 0.025). Their pre-test probability of obstructive CAD was lower (13% [IQR 10-24] vs 22% [IQR 11-26], p=0.010), and multivessel disease on CCTA was less frequent (20% vs 37%, p=0.002). During a median follow-up of 31 months, 108 patients had the combined endpoint, with no significant differences between the groups. In conclusion, patients with obstructive CAD and low CACS have a specific clinical profile that is important to consider in the diagnostic strategy of the patient with suspected CAD.