77909-0

LOINC code 77909-0 identifies "Aortic valve Effective regurgitant orifice area by US.doppler+Calculated by PISA method". The effective regurgitant orifice area (EROA) is the size of the defect where the valve leaflets are not aligning normally (coaptation defect). The severity of regurgitation is related to the EROA. Proximal isovelocity surface area (PISA) is a method for calculating the EROA using color flow Doppler and is based on flow dynamics and the continuity principle, which states that in the absence of a leak or additional flow into a conduit, the flow rate will be constant along the length of the conduit, whether the conduit is the heart or the regurgitant jet. The EROA is calculated from the flow and peak velocity at the regurgitant orifice, where the flow is based on the radius at the orifice and the Nyquist limit (aliasing velocity), which is the velocity at which the color flow switches from red to blue or blue to red, and the peak velocity is measured using continuous wave Doppler of the jet. [PMID: 17898369]

This code measures Effective regurgitant orifice area in Aortic valve. It belongs to the CARD.US class in the LOINC classification.

LOINC (Logical Observation Identifiers Names and Codes) is a universal standard for identifying laboratory and clinical observations. It is maintained by the Regenstrief Institute and used worldwide for health data exchange.