Noninvasive Hemodynamics

Pulmonary diastolic pressure

Fig. 1
Fig. 2

Pulmonary artery diastolic pressure (which approximates pulmonary capillary wedge pressure) = mid-diastolic regurgitant pressure gradient (see below) + RV diastolic pressure (approximated by right atrial pressure, which is estimated from inferior vena cava inspiratory collapse).
Fig. 1: Estimated normal wedge pressure. Continuous wave Doppler tracing, transthoracic examination. Normal subject with minimal pulmonary valve regurgitation.  End-diastolic gradient= 3.9 mmHg. Assuming normal (= 6 mmHg) right atrial pressure, wedge pressure= 3.9 + 6= 9.9 mmHg.
Fig. 2: Estimated increased wedge pressure. Continuous wave Doppler tracing, transthoracic examination. Patient with minimal pulmonary valve regurgitation. Diastolic gradient= 15.2 mmHg. Assuming normal (= 6 mmHg) right atrial pressure, wedge pressure= 15.2 + 6= 21 mmHg. 

Transesophageal examination, Long axis (119°) of the base, color Doppler flow imaging

A. In blue, normal systolic laminar flow through the right ventricular (RV) outflow tract, valve and pulmonary artery (PA). To the right (and at center of sector scan) short axis of the aortic root. 

B: in yellow/red, mild diastolic pulmonary valve regurgitation. The continuous wave Doppler cursor is positioned through, and parallel to, the regurgitant jet, to obtain the diastolic regurgitant flow velocity pattern. 


Left atrial pressure

Left atrial pressure (mid-systole) = radial artery systolic pressure – maximum pressure gradient of mitral regurgitation.
LAPms= Systolic radial artery pressure (cuff) – DP = 125 – 117= 8 mmHg. 

Radial artery pressure measured by sphygmomanometry (125 mmHg in the example). 
DP: pressure gradient between peak aortic systolic pressure and mid-systolic left atrial pressure, which can be calculated (simplified Bernoulli equation, P= v2 x 4) from the peak velocity of mitral regurgitation;
a: left atrial peak a pressure
AOP: Aortic pressure
LAP: left atrial pressure;
LAPms: left atrial mid-systolic pressure;
LVP: left ventricular pressure
v: left atrial peak v pressure.

Right panel: transesophageal evaluation of mitral regurgitation.

Transthoracic evaluation of mitral regurgitation associated with left ventricular systolic dysfunction (note reduced slope of velocity increase during isovolumic contraction), and elevated left atrial pressure.
Cuff radial pressure= 90 mmhg
LAPms= 90 – 57.2 = 32,8 mmHg. 

Transthoracic evaluation of mitral regurgitation associated with mild reduction of left ventricular systolic function and increased left atrial pressure.
Cuff radial pressure= 100 mmHg
LAPms= 100 – 67.6 = 32,4 mmHg