Canonical: https://echosuite.app/guides/aortic-stenosis/ # Aortic valve area calculator: continuity equation and stress echo Explore aortic valve area with the continuity equation, the required LVOT and aortic Doppler measurements, and the tool’s stress-echo options. Created by [Mohammed Kamareddine, MD](https://echosuite.app/about/) · [Sources & educational scope](https://echosuite.app/about/) [Open interactive calculator →](https://echosuite.app/calculators/#aortic-stenosis) ## Method AVA = LVOT area × LVOT VTI ÷ AV VTI Use the measurement units shown below. Some fields apply only to a selected method or condition; follow the interactive tool’s method choices. The interactive tool keeps missing measurements incomplete and provides its method-specific results and reference context. ## Measurements and acquisition ### Measurement Enter the measured value in the displayed unit - Resting continuity - Stress comparison - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ### LVOT diameter cm 2D echo · inner-edge measurement - Use the specified view and cardiac phase. - Align the calipers perpendicular to the structure’s long axis. - Measure inner edge to inner edge and avoid oblique foreshortening. ### LVOT VTI cm Pulsed-wave Doppler - Place the sample volume at the specified annulus or outflow tract. - Align the Doppler beam with flow and record a clean envelope. - Trace the modal velocity envelope and use the reported VTI. ### Aortic valve VTI cm Continuous-wave Doppler trace - Use the same aligned CW recording as the peak velocity. - Trace the outer edge of the dense envelope for the relevant phase. - Use the machine-reported VTI in centimeters. ### Body surface area m² Record the units, date and measurement source - Use measured height and weight where feasible. Record the units, date and whether a value was reported or estimated. - Fluid status and weight changes affect BSA. Document any substituted weight; do not silently replace measured weight with ideal or dry weight. - Use the unit named by the field. BSA is in m²; height and weight can be converted in the Body surface area calculator. Keep the formula with serial indexed results. ### Peak AV velocity m/s Continuous-wave Doppler - Align the CW cursor as parallel as possible to the jet. - Acquire a dense, complete envelope without truncation. - Measure the highest absolute velocity on the selected envelope. ### Mean AV gradient mmHg Complete traced CW envelope - Align through the valve or shunt and record a complete envelope. - Trace the modal velocity envelope using the machine tool. - Use the machine-calculated mean gradient in mmHg. ### LVEF category Enter the measured value in the displayed unit - Preserved · ≥50% - Reduced · <50% - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ### Rest · stroke volume mL Enter the measured value in the displayed unit - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ### Stress · stroke volume mL Enter the measured value in the displayed unit - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ### Rest · AVA cm² Enter the measured value in the displayed unit - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ### Stress · AVA cm² Enter the measured value in the displayed unit - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ### Rest · mean gradient mmHg Enter the measured value in the displayed unit - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ### Stress · mean gradient mmHg Enter the measured value in the displayed unit - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ### Rest · ejection time ms Enter the measured value in the displayed unit · Optional - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ### Stress · ejection time ms Enter the measured value in the displayed unit · Optional - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ### Stage acquisitions Enter the measured value in the displayed unit - Matched & reliable - Not comparable - Uncertain - Confirm the variable matches the selected formula. - Use the unit displayed beside the field. - Keep measurements from the same representative hemodynamic state. ## Sources and method context European Association of Cardiovascular Imaging and American Society of Echocardiography · 2017 · Recommendations on the Echocardiographic Assessment of Aortic Valve Stenosis: A Focused Update · Continuity equation and acquisition pp. 4–11 · Table 3 p. 12 · discordant AS pp. 12–15 · integrated pathway and Figure 8 pp. 16–17 [Primary reference](https://www.asecho.org/wp-content/uploads/2017/04/2017ValveStenosisGuideline.pdf) - Continuity equation & acquisition · Sections on peak velocity, mean gradient and AVA · PDF pp. 4–11 Multiwindow CW acquisition, LVOT diameter and PW sampling, continuity-derived AVA, indexed AVA, and velocity/VTI ratio. - Hemodynamic ranges · Table 3 · PDF p. 12 Peak velocity, mean gradient, AVA, indexed AVA, and velocity-ratio ranges and boundary conventions. - [Flow-aware discordance and stress comparison](https://doi.org/10.5935/abc.20180018) · Discordant-AS sections pp. 12–15 · Figure 8 and integrated pathway pp. 16–17 Resting discordance pathway and DSE acquisition/reporting, PDF pp.13–14: same baseline LVOT diameter, stage SV/area/gradient comparison, >20% SV reserve and projected area at 250 mL/s. Projection equation and ≥15% Q-change condition: Ferreira et al., Arq Bras Cardiol 2018;110:132–139, Methods/Discussion, doi:10.5935/abc.20180018. Catalogue review status: Exact guideline locator mapped · clinical sign-off pending These pages describe the educational tool. 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