Pulmonary Vascular Resistance (PVR) Estimate Using TRV/VTIRVOT: Explanation and Clinical Context Pulmonary vascular resistance (PVR) is a critical parameter in assessing pulmonary hypertension. The TRV/VTIRVOT method provides a non-invasive echocardiographic estimate of PVR, based on the relationship between the peak tricuspid regurgitation velocity (TRV) and the right ventricular outflow tract time-velocity integral (VTIRVOT).
The formula used is: PVR (Wood units) = 10 × TRV / VTIRVOT.
Normal PVR values range approximately from 1 to 3 Wood units. Elevated PVR indicates increased resistance in the pulmonary circulation, which can result from pulmonary arterial hypertension, left heart disease, or chronic thromboembolic disease.
This non-invasive estimate can aid in risk stratification, monitoring response to therapy, and guiding further diagnostic evaluation. It complements invasive measurements like right heart catheterization but is valuable in routine clinical practice when catheterization is not immediately feasible.
Reference:
Abbas AE, Fortuin FD, Schiller NB, Appleton CP, Moreno CA, Lester SJ. A simple method for noninvasive estimation of pulmonary vascular resistance. J Am Soc Echocardiogr. 2003;16(8):975-981. doi:10.1016/s0894-7317(03)00309-5