Use of New Generation Carotid Ultrasound for Non-Invasive Prediction of Severe Coronary Artery Disease

Background: Increased carotid intima-media thickness (cIMT) has been extensively evaluated as a marker of cardiovascular risk. However, there are only limited data correlating cIMT and other carotid measurements with the presence and anatomical severity of coronary artery disease (CAD). Methods: Patients with a history of ischemic-type chest pain or angina equivalent undergoing Invasive Coronary Angiography (ICA) or Computed Tomography Coronary Angiography (CTCA) underwent high-resolution B-mode ultrasound to measure cIMT and B-mode 3D-imaging to measure total plaque volume and maximum area reduction using latest generation hardware and software. Age and sex-adjusted cIMT normal ranges were defined based on previous independent population studies. The study was supported by a European Union INTERREG VA Programme grant. Results: The study population comprised 166 subjects (71.7% male). Mean age was 66.3±11.58SD years. Cardiovascular risk factors included family history of CAD (74%), current or ex-smoker (59%), history of hypertension (67%), hyperlipidemia (68%) or diabetes (22%). On ICA or CTCA, severe disease (≥70% area stenosis or positive pressure wire study) was present in at least 1 coronary artery in 115 (69.3%) of patients. Severe multivessel disease was present in 72 (43%) of patients. cIMT ≥50th percentile vs cIMT <50th percentile predicted the likelihood of severe disease in at least 1 coronary artery (82.5% vs 27.5%; relative risk 3.0; p<0.00001; positive predictive value 82%, negative predictive value 73%; accuracy 80%). Similarly, cIMT ≥50th percentile predicted the likelihood of severe disease multivessel disease (54.4% vs 15%; relative risk 3.4; p<0.00001). While cIMT ≥75th percentile was also associated with likelihood of single or multivessel disease, it did not improve the predictive value compared with the cIMT ≥50th percentile. 3D imaging of total plaque volume and maximum area reduction did not significantly improve prediction of CAD. Conclusion: cIMT ≥50th percentile predicted an increased risk of severe CAD in at least one or more vessels and may therefore be a useful tool to help identify patients most likely to benefit from further invasive investigation.