Why and How to Measure Aortic Valve Calcification in Patients With Aortic Stenosis

The first-line evaluation of aortic stenosis severity is Doppler echocardiography. However, in up to 40% of patients, resting echocardiographic assessment of aortic stenosis severity is discordant, leading to clinical uncertainty. Interest has therefore grown in aortic valve calcium scoring by multidetector computed tomography (CT-AVC) as an alternative load independent assessment of aortic stenosis severity. This paper will briefly review the pathophysiology of aortic stenosis and the crucial role that calcification plays in driving progressive obstruction of the valve. Subsequently, it will describe published reports that have investigated CT-AVC, validating this parameter against histology, and establishing its diagnostic accuracy versus echocardiography as well as its powerful independent prognostic capability. Finally, this review seeks to provide a practical guide about how best to acquire and interpret CT-AVC with a close focus on potential pitfalls and how these might be best avoided as this technique becomes more widely adopted in to clinical practice. • Measurement of aortic valve calcification is useful in assessing aortic stenosis severity in patients for whom echocardiography is not conclusive. • Aortic valve calcification should be measured on noncontrast electrocardiogram-gated computer tomography scans (120 kV to 140 kV; 60% to 80% RR interval) with the use of the Agatston method. • Calcification of left ventricular outflow tract, aorta, mitral annulus, and coronary arteries should carefully be excluded from the measurement of aortic valve calcification. • An aortic valve calcification score higher than 1,300 AU in women or 2,000 AU in men should be considered severe.