Clinical significance of aortic knob width and calcification in unstable angina

Chest radiography is a routine examination evaluating those patients with chest pain. There are few data about the correlation between aortic knob width, calcification and coronary atherosclerosis.

The aortic knob width was measured and the presence of aortic knob calcification was assessed via a chest posteroanterior view in 178 consecutive patients. The aortic knob width and calcification were compared to the risk factor and the extent of coronary artery disease. Patient's age (69.5+/-7.95 vs 61.1+/-10.29 years, p=0.010), the prevalence of hypertension (65.9 vs 46.3%, p=0.024) and diabetes (43.2 vs 26.1%, p=0.033), the level of total cholesterol (196.8+/-63.21 vs 188.6+/-44.45 mg/dl, p=0.049) and the incidence of multi-vessel disease (65.9 vs 38.1%, p<0.001) were higher in patients with aortic knob calcification than in patients without calcification. The aortic knob width and the prevalence of aortic knob calcification were significantly correlated with the severity of coronary artery disease. Multivariate analysis demonstrated that aortic knob calcification and diabetes were independent factors for multi-vessel disease (p=0.018 and p=0.012).

The observation of aortic knob on a chest radiograph can provide important predictive information of coronary atherosclerosis.