Emergency and critical care physicians should always consider the diagnosis of critical aortic stenosis in elderly patients with new onset shortness of breath, chest pain, and syncope [1–4]. Patients with symptomatic critical aortic stenosis will require surgical aortic valve replacement [1–4]. The American Society of Echocardiography has defined a severely stenotic aortic valve areas less than 1.0 cm2 [1]. The aortic valve area can be estimated with Doppler echocardiography using the simplified continuity equation [2, 3]:
where CSA = the cross-sectional area [π(D(diameter)/2)2] = 0.785D2, LVOT = left ventricular outflow tract, VelocityLVOT-Max = Maximal pulsed-wave Doppler velocity at the LVOT, and VelocityAV-Max = Maximal continuous-wave Doppler velocity through the AV.
Using the simplified continuity equation, our symptomatic patient’s ED calculated AVA area measurement was 0.28 cm2 and the formal Cardiology calculated AVA measurement was 0.7 cm2, both considered to be critical aortic stenosis in our patient with chest pain and shortness of breath [1]. Our underestimation of the AVA compared to the Cardiology AVA measurement was due to our underestimation of the LVOT diameter, 1.43 versus 2.0 cm Cardiology LVOT measurement. The LVOT diameter measurement is the most common measurement error when calculating the AVA in patients with aortic stenosis as this inner edge to inner edge measurement can be difficult in patients with severe aortic valve calcification, as was the case in our patient [1]. In addition, because the LVOT diameter measurement is squared [π(D/2)2], any LVOT measurement errors are amplified further. Symptomatic patients with critical aortic stenosis are best surgically managed with aortic valve replacement [1–4]. Rapidly identifying a patient with critical aortic stenosis in the ED or intensive care unit can expedite the important cardiothoracic surgical consultation and ultimate surgical treatment that the majority of these patients will require.