Lack of a Tricuspid Regurgitation Doppler Signal and Pulmonary Hypertension by Invasive Measurement.

Transthoracic echocardiography (TTE) is used to estimate pulmonary artery systolic pressure, but an adequate tricuspid regurgitation velocity (TRV) needed to calculate pulmonary artery systolic pressure is not always present. It is unknown whether the absence of a measurable TRV signifies normal pulmonary artery pressure.