Brief report

Superior vena cava and hepatic vein velocity patterns in normal children

Patients who underwent Fontan operation have some degree of liver disease. We aimed to assess the long-term liver and cardiac function after Fontan operation.

Patients enrolled underwent physical examination, biochemical tests (aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transpeptidase, bilirubin, international normalized ratio, coagulation factor V, protein profile, fecal alpha-1-antitrypsin), echocardiogram, and liver ultrasonography. A liver disease score was adopted to compare the degree of liver involvement with hemodynamic features.

The study enrolled 34 patients, median age 14.7 years (range, 4.1 to 26.7), 26 with a residual left ventricle, 8 with a residual right ventricle, affected by tricuspid atresia (17), pulmonary atresia (4), hypoplastic left heart syndrome (5), double-outlet right ventricle (2), single left ventricle (2), and miscellaneous (4), with median follow-up of 11.5 years (range, 1.7 to 23.3). We found hepatomegaly in 18 of 34 (53%), splenomegaly in 3 of 33 (9%), abnormal transaminases in 10 of 33 (30%), elevated γGT in 19 of 31 (61%), elevated bilirubin in 10 of 31 (32%), coagulopathy in 17 of 29 (58%), and protein-losing enteropathy in 4 of 21 (19%). Median heart rate z-score was −1.72. Hepatic dysfunction was strictly correlated to low cardiac index (r² = 0.34, p = 0.008) and to a lesser extent to reduced heart rate (r² = 0.18, p = 0.07).

In children who underwent Fontan operation, hepatic dysfunction is correlated with low cardiac index and reduced heart rate. Maintaining or reestablishing a normal cardiac index might prevent or reduce liver disease in the long-term.

Thrombosis of the superior vena cava (SVC) is an important clinical problem that requires prompt diagnosis. Confirmation of suspected SVC syndrome requires the use of an imaging study to document the obstruction and presence of collateral venous channels. Echocardiography is often used to evaluate suspected SVC obstruction; however, previous methods have allowed only indirect detection of collateral flow. We describe 3 patients with SVC obstruction in whom color flow Doppler allowed direct demonstration of collateral venous channels. (J Am Soc Echocardiogr 2000;13:780-4.)

The reference values for right ventricular (RV) filling of normal persons and the effects of physiologic variables in a large series have not been described. The objective of this study was to characterize superior vena cava, hepatic vein, and RV inflow Doppler measurements in a large normal reference group to reflect the aging process, gender, heart rate, and effects of respiration. We prospectively performed pulsed-wave Doppler echocardiography of the superior vena cava, hepatic vein, and RV inflow during inspiration, expiration, and apnea in 115 healthy volunteers (62 women and 53 men) ranging in age from 21 to 84 years (mean ± SEM 48 ± 17). For analysis, the study subjects were classified by age into 2 groups: those <50 years of age (group 1; n = 60) and those ≥50 years of age (group 2; n = 55). Multiregression models were used to assess the influence of age, gender, and heart rate on Doppler variables. There were important differences in superior vena cava and RV inflow between the 2 groups. Group 2 had a greater superior vena cava peak atrial flow velocity (16 ± 3 vs 13 ± 3 cm/s), flow integrals (1.5 ± 0.4 vs 1.1 ± 0.3 cm), and reverse flow as a percentage of forward flow (17 ± 6% vs 14 ± 6%) than group 1. In group 2, peak RV inflow early filling velocity (41 ± 8 vs 51 ± 7 cm/s) and ratio of early filling-to-atrial filling (1.3 ± 0.4 vs 2 ± 0.5) were lower than that of group 1. Likewise, peak atrial filling velocity was higher (33 ± 8 vs 27 ± 8 cm/s) and deceleration time was longer (198 ± 23 vs 188 ± 22 ms) in group 2. The superior vena cava and hepatic vein peak forward flow velocities were significantly higher during inspiration than during expiration and apnea. Similarly, RV inflow velocities were significantly higher during inspiration than in expiration and apnea. Multiregression analysis showed that age, gender, and heart rate had important effects on Doppler variables. Thus, this study demonstrates the effects of aging and normal physiologic variable flow velocities in the superior vena cava, hepatic veins, and RV inflow in a large series of normal subjects.

The important finding of this study was that Doppler assessment of hepatic venous velocities demonstrates reduced or negative velocities in the first half of diastole in children with right ventricular hypertension. The only other hepatic venous waveform change occurred during end-diastole and atrial contraction. At that time amplitude of reversed blood velocity in the hepatic vein increased directly with increased right ventricular pressure, but the magnitude of increase was not clinically significant.