Abstract 344: Significance of Pre-test Likelihood of Coronary Artery Disease in Patients With Coronary Artery Calcium Score Zero
Background: Coronary artery calcium score (CACS) by MSCT is assessed as a gatekeeper for CT coronary angiography (CTA). It was also recommended that clinical history and other conventional clinical criteria such as the likelihood of the presence of coronary artery disease (CAD) should be used for decision making of CTA. However there is a controversy about the management for patients with CACS Zero
Objective: To evaluate the significance of pre-test likelihood of CAD in patients with CACS zero.
Methods: CACS was assessed in 270 consecutive patients with suspected CAD undergoing CTA. In this study, 87 patients (32.2%) with CACS zero were included. Obstructive CAD was defined as a ≥ 75% reduction in diameter in at least one major vessel in CTA. Non-obstructive CAD was defined as a 25–75% reduction. Normal coronary was defined as no coronary plaque. According to a modification of the Diamond and Forrester methods, as presented by Morise, patients were classified as having a low (score 0–8), intermediate (score 9–15), or high pre-test likelihood (score > 16) of CAD based on age, gender, symptom, estrogen status, and CAD risk factors (diabetes mellitus, hypertension, smoking, hyperlipidemia, family history, and obesity). CTA findings were compared with the pre-test likelihood of CAD.
Result: Three patients were excluded because of motion artifact. Of 84 patients, CTA revealed that 5 patients (6%) had obstructive CAD, 6 (7.1%) had non-obstructive CAD and 73 (86.9%) had normal coronary. In assessment for pre-test likelihood of CAD, 16 patients (19.1%) had a low pre-test likelihood, 50 (59.5%) had an intermediate, and 18 (21.4%) had a high. In 5 patients with obstructive CAD in CTA, 3 patients with a high pre-test likelihood of CAD, and 2 with an intermediate were observed. In 6 patients with non-obstructive CAD, 1 patient with a high pre-test likelihood of CAD, and 5 with an intermediate were observed. Normal coronary was observed in all of the 16 patients (19.1%) with a low pre-test likelihood.
Conclusion: CACS zero by MSCT did not rule out the patient with obstructive and non-obstructive CAD completely. Even for the patients with CACS zero, CTA may be considered except the patients with a low pre-test likelihood.