Quick Calculation of Aortic Stenosis with Bedside Ultrasound

71 year old male with PMH ESRD and extensive cardiac history including CAD, CHF, A-fib, aortic valve stenosis and pHTN in the MICU for neurosurgical evaluation of a traumatic spinal fracture. During his stay, he was found to be hypotensive and short of breath. Beside ultrasound was used to evaluate his heart, IVC, and lungs. We were interested in evaluating his cardiac status to see if any changes had occurred since his last formal echo performed roughly a month prior. We calculated his aortic valve area (AVA) using the continuity equation to see how severe his aortic stenosis was. First, we measured LVOT diameter in parasternal long view then in an apical view we obtained pulsed wave doppler of velocity of the outflow tract and continuous wave doppler recording at the aortic valve. The continuity equation was applied to calculate the aortic valve area. We found our patient had moderate aortic stenosis of 1.4 cm2, which was consistent with the cardiologist’s value of 1.39 cm2 obtained a month prior.

AVA= [Pie * [{(LVOT/2)2]* VTI1]]/ VTI2
VTI1= VTI LVOT
VTI2= VTI Aortic Valve
LVOT= Left Ventricular Outflow Tract Diameter

Grading:
Mild >1.5 cm2
Moderate 1-1.5 cm2
Severe <1cm2

A case report published in the critical ultrasound journal in 2010 describes a patient in an emergency room with SOB and chest pain found to have severe aortic stenosis through bedside ultrasound and use of the simplified continuity formula. The patient later underwent formal echo with cardiology, which confirmed the severe disease. The article highlights the benefits of bedside ultrasound aiding both emergency and critical care physicians in quick diagnosis of critical aortic stenosis.

Riley, D, et al. (2010). Emergency department diagnosis of critical aortic stenosis using bedside ultrasonography. Critical Ultrasound Journal. 2:87-89. DOI 10.1007/s13089-010-0047-6

 

Nicolette Metrusias, PGY1 EM