Abstract 2427: Can Carotid Intima-Media Thickness Measurement Predict which Patients with Abnormal Stress Tests will have Significant Coronary Disease?
BACKGROUND: False positive stress-tests (GXT) are not infrequent in clinical practice. Atherosclerosis is a systemic disease, easily detected by measuring carotid intimal-medial thickness (IMT). Whether carotid IMT can predict which patients with abnormal GXT will have significant coronary disease (CAD) by angiography, has not been studied.
METHODS: Mean and maximal carotid IMT was measured by B-mode ultrasound in 40 patients without known CAD, who were scheduled to undergo diagnostic coronary angiography, subsequent to abnormal GXT with imaging. Mean IMT was calculated as the average of 12 measurements of the near and far walls of distal common carotid, bifurcation and proximal internal carotid arteries. Maximum thickness of any visible plaque was recorded as maximal IMT. Based on literature review, mean IMT > 0.9mm and maximal IMT > 1.3 mm were considered abnormal. Pre-test probability was calculated by age, gender and nature of symptoms using the nomogram published in the ACC/AHA 2002 guidelines. CAD was defined as any luminal stenosis > 50% by angiography. All images were digitally stored and reviewed by independent, blinded readers.
RESULTS: Forty patients (50% women) with a mean age of 60 years (32 – 85) were enrolled. Hypertension was present in 69%, dyslipidemia in 59% and diabetes in 32%. Mean IMT was thickened in half (n=21) of the patients, 67% (14/21) of whom had CAD by angiography. Only 3 of the 19 patients (16%) who had a normal IMT and an abnormal GXT had CAD (p = 0.002). Maximal IMT > 1.3 mm was associated with CAD in 58% patients, compared with 14% CAD in patients with a maximal IMT ≤ 1.3mm (p = 0.02). On multivariate analysis, both clinical pre-test probability and CIMT were independent predictors of angiographic CAD.
CONCLUSIONS: 1. Both mean and maximal carotid IMT are predictive of angiographic CAD. 2. In patients with abnormal GXT, carotid IMT can help predict the presence or absence of angiographic CAD.