DK2985_C000 1..28 - AlSharqia Echo Club

112 Transesophageal EchocardiographyFigure 5.31 Estimation of right ventricular systolic pressure (systolic Prv or RVSP) using the pressure gradient (PG) obtained fromtricuspid regurgitation (TR) and right atrial pressure (Pra or RAP) in a 46-year-old woman with aortic valve endocarditis. (A) Hemodynamicpressure tracing: after cardiopulmonary bypass, a difference between the systolic Prv and pulmonary artery pressure (Ppa)was observed. (B) Continuous wave Doppler: a PG of 42.8 mmHg would yield a RVSP of 50.8 mmHg. However, the Ppa is measuredat 24/12 mmHg. The suspected right ventricular outflow tract obstruction is confirmed by direct measurement of a systolic Prv (or RVSP)of 46 mmHg using the right ventricular paceport of the Ppa catheter (EKG, electrocardiogram; Pa, arterial pressure; V, velocity).shortened as much, despite high pulmonary pressures,when the right ventricular cardiac output is increasedwith left-to-right shunt.4. Pulmonary Artery and Right Ventricular(End)-Diastolic PressureAt the end of diastole, the right atrial pressure and the rightventricular pressure should have equalized, assuming thereis no evidence of tricuspid valve stenosis (Fig. 5.32).Therefore, the following equation can be rewritten as (37):PAEDP ¼ 4(V PR-ED) 2 þ RVEDP(5:28)PAEDP ¼ 4(V PR-ED) 2 þ RAPwhere PAEDP is the pulmonary artery end-diastolic pressure(in mmHg); V PR-ED is the end-diastolic pulmonaryregurgitant velocity (in m/s); RVEDP is the right ventricularend-diastolic pressure (in mmHg); and RAP is themeasured or estimated right atrial pressure (see below)(in mmHg).pressure estimated by physical examination or an empiricalvalue of 10 was evaluated and compared with otherregression equations (33).A normal-sized inferior vena cava (IVC) collapses witha rapid negative intrathoracic pressure during a suddeninspiration (“sniffing” maneuver). When the right atrialpressure increases, there is decreased venous return andcompensatory increase in the IVC diameter which servesas a capacitance reservoir for the RA.Moreover, during sniffing, the decrease in IVC diameteris either blunted or absent with high right atrial(RA) pressure (41). Table 5.1 has been proposed to estimatemean RAP.Correlation studies with catheterization have alsoshown that combined information from the IVC diameterand the hepatic venous Doppler profile can be used toassess RAP (42) (Table 5.2).The preceding estimate of RAP was however notprospectively validated in patients on positive pressuremechanical ventilation.5. Right Atrial PressureSeveral methods have been proposed to estimate the rightatrial pressure used in the preceding equations to measureright-sided intracardiac pressures. The jugular venous6. Left Ventricular End-Diastolic PressureThe aortic regurgitant velocity reflects the instantaneouspressure gradient between the aorta and the LV duringdiastole (Fig. 5.33). As the arm diastolic blood pressure