Noninvasive estimation of systolic pressure in the right ventricle in patients with tricuspid regurgitation

In 70 patients, tricuspid regurgitation was diagnosed with Dopplerby recording reverse flow in systole originating at the tricuspidorifice, directed into the right atrium. The peak velocitieswere recorded, and the peak pressure drop from the right ventricleto the right atrium in systole was calculated from the simplifiedBernoulli equation (pressure drop = 4x4x Vmax²), and was foundto correlate well with invasive measurements (r = 0.97, SEE±61mmHg). Central venous pressure was judged by neck vein congestionand added to the pressure drop to obtain a noninvasive estimationof systolic right ventricular pressure. Correlation with catheterizationmeasurements was good (r = 0.96, SEE±7.1 mmHg). In patientsin whom the tricuspid regurgitation was judged as mild withDoppler, the correlation between noninvasive and invasive measurementsof the transtricuspidpressure drop was still good (r = 0.95,SEE±5.1 mmHg), indicating that the viscosity of the blooddoes not invalidate the use of the simplified Bernoulli equationwhen the regurgitant area of the valve is small.