Association between carotid ultrasound features and the detection of functionally significant coronary artery stenosis: a prospective study based on quantitative flow ratio

Background: Carotid ultrasound is a helpful approach for classifying cardiovascular risk. Quantitative flow ratio (QFR) is used to evaluate functionally significant coronary artery stenosis (CAS). The aim of this prospective study was to investigate the correlation between carotid artery features from carotid ultrasound and functionally significant CAS. Furthermore, this study aimed to evaluate the diagnostic performance of carotid ultrasound in diagnosing functional CAS. Methods: Carotid ultrasound was performed in 82 patients with suspicious coronary artery disease, measuring carotid intima-media thickness (IMT), internal artery diameter (IAD), and carotid plaques. QFR values were measured in all patients, and functionally significant CAS was defined as QFR <= 0.8. Forty patients (48.8%) had non-functionally significant CAS with QFR >0.8, while 42 patients (51.2%) had functionally significant CAS with QFR <= 0.8. Logistic regression analyses were performed to evaluate the association among functionally significant CAS, carotid ultrasound features and clinical parameters. A receiver operating characteristic (ROC) curve was developed to assess the capability of carotid ultrasound to diagnose functionally significant CAS. Results: Patients with functionally significant CAS (QFR <= 0.8) had greater IMT, carotid bifurcation IAD and internal carotid artery-IAD, compared to patients with non-functionally significant CAS, with P values of <0.001, 0.015, and 0.011, respectively. The presence of carotid plaque was significantly higher in the functionally significant CAS group (95.2%) compared to the non-functionally significant CAS group (60%), with a P value of <0.001. In multivariable logistic regression analysis, maximum plaque height (MPH) (OR: 1.777, P=0.018) was associated with functionally significant CAS in patients with coronary artery disease. ROC curves showed plaque area to be superior to IMT, MPH and plaque length in identifying functionally significant CAS. The cutoff value of the plaque area was 9.07, and the sensitivity and specificity were 85.7% and 70.0%. Conclusions: Carotid artery properties measured by carotid ultrasound were associated with functionally significant CAS. Plaque area is the most clinically useful parameter for detecting functionally significant CAS compared to IMT, MPH, and plaque length.