Abnormal Venous Flow in Pregnant Women with Mild Right Ventricular Dysfunction in Repaired Tetralogy of Fallot: A Clinical Model for Organ Dysfunction in Preeclampsia

Figures

• 

  Figure 1. Explanation of the different venous Doppler wave deflections in the liver and kidneys, in relation to the cardiac cycle in the right atrium. A is the consequence of atrial contraction at the end of ventricular diastole. Due to the lack of valves between right atrium and vena cava, there is a retrograde jet of venous blood into the venous system causing a peak of reversed flow in the liver, and a deceleration of forward flow in the kidneys. X represents forward venous flow during right atrial diastole. V is the deceleration of forward venous flow when the right atrium is filled while the tricuspid valve is still closed. This may sometimes cause retrograde flow in hepatic veins (tetraphasic waves) as illustrated in our case series. Y represents forward venous flow during ventricular diastole with open tricuspid valve. Venous Impedance Index is defined as (X − A)/X. Venous pulse transit is defined as [time interval between ECG-P and Doppler A]/ECG R-R time interval.

• 

  Figure 2. Hepatic and renal venous flow in 3 pregnant women with ToF ((C,E,G) and (D,F,H), respectively) versus hepatic and renal venous flow in healthy pregnant women ((A) and (B), respectively) at 20–24 weeks gestation. Healthy controls: (A) + (B); Case 1: (C) + (D); Case 2: (E) + (F); Case 3: (G) + (H). BF, backward flow; FF, forward flow. In both liver and kidneys, backward/discontinuous flow (red arrow and red dots) were seen in pregnant women with ToF, which is in contrast to the forward/continuous flow (green arrow and green dots) in healthy controls at 20–24 weeks gestation.

• 

  Figure 3. (A) Orange waves: Illustration of the gestational changes in hepatic and intrarenal venous Doppler waveforms from first to third trimester in normal pregnancies, and the patterns observed in preeclampsia. (B) White waves: Illustration of discontinuous intrarenal venous Doppler waveforms in non-pregnant individuals with increasing grade of venous congestion (Figure adapted from [19]). In pregnant women, triphasic hepatic venous Doppler waveforms become flat during the course of normal pregnancy, and biphasic intrarenal waves become monophasic. In preeclampsia, however, tri- to tetraphasic hepatic venous waveforms are present, and in the kidneys sharp decelerations of forward venous flow are observed during A- and V-waves. In the kidneys of non-pregnant individuals, discontinuous venous Doppler waves are observed, evolving from pulsatile to monophasic in parallel with degree of congestion.