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

<b>Background:</b> Pregnant women with congenital heart disease carry a high risk of complications, especially when cardiac function is suboptimal. Increasing evidence suggests that impaired right ventricular (RV) function has a negative effect on placental function, possibly through venous congestion. We report a case series of hepatic and renal venous flow patterns in pregnant women with right ventricular dysfunction after repaired Tetralogy of Fallot (ToF), relative to those observed in normal pregnancy and preeclampsia. <b>Methods:</b> At 20-24 weeks pregnancy, RV function was measured by echocardiography and by cardiovascular magnetic resonance in women with repaired ToF. Combined Doppler-ECG of the hepatic and renal interlobular veins were performed in three women with asymptomatic right ventricular dysfunction. Venous impedance index and pulse transit time were measured and classified as abnormal at >75th and <25th reference percentile, respectively. <b>Results:</b> All three women showed dilated RV and mildly impaired RV function. Both hepatic and intrarenal Doppler flow waves were abnormal and very much resembled the patterns seen in preeclampsia. One of the three women had complications including ventricular tachycardia, intrauterine growth restriction, antenatal bleeding, emergency cesarean section and acute heart failure 2 days postpartum. <b>Conclusions:</b> Pregnant women with mild right ventricular dysfunction after repaired ToF show abnormal venous Doppler flow waves in the liver and kidneys, similar to those observed in preeclampsia. These findings are in line with reported observations on the association between impaired RV function, abnormal return of venous blood, venous congestion and organ dysfunction. The parallel with venous Doppler flow observations in preeclampsia suggest that the venous compartment might play an important role in the etiology of preeclampsia-induced organ dysfunction. Whether this phenomenon directly affects the uteroplacental circulation is to be assessed in future research.