Estimation of the systolic pulmonary arterial pressure using contrast-enhanced continuous-wave Doppler in patients with trivial tricuspid regurgitation

Noninvasive estimation of pulmonary arterial pressure is important for hemodynamic monitoring of patients with heart disease. In patients with tricuspid regurgitation (TR), the peak velocity of TR on continuous-wave (CW) Doppler can be used to estimate the systolic pulmonary arterial pressure (PAPs) using the simplified Bernoulli equation. We evaluated a new technique of contrast-enhanced CW Doppler for calculating PAPs in patients with trivial TR. Forty-one patients without visible TR detected by color Doppler, pulsed Doppler or CW Doppler were evaluated. Age ranged from 19 to 73 (55 +/- 12) years old. Tricuspid flow signals were recorded on CW Doppler after intravenous administration of indocyanin green (ICG) or Albunex. PAPs was calculated as; PAPs = 4 x V-TR(2) + 10 mmHg, where VTR is the peak velocity of TR. PAPs calculated using contrast-enhanced CW Doppler was compared with PAPs measured by the following cardiac catheterization. 1) TR signals were recorded using the contrast-enhanced CW Doppler technique in 39 of 41 patients (95%) after intravenous administration of contrast agents. 2) The error of estimate of PAPs using the contrast-enhanced CW Doppler technique was - 2.4 +/- 7.5 mmHg, and the percent error was -10.7 +/- 32.4% in all patients. In 20 of 39 patients (51%), the error of estimate was within + 5 mmHg. 3) PAPs was overestimated by 12.2 +/- 6.1 mmHg in patients with good contrast enhancement of TR signals. The contrast-enhanced CW Doppler technique is useful for estimating PAPs noninvasively in patients with trivial TR. It is better to assume the right atrial pressure as 3-5 mmHg, not 10 mmHg, in patients with good enhancement of trivial TR. Physiological TR may be enhanced by contrast agents in these patients.