Children's Hospital Colorado

Right Atrial Dysfunction in Fetuses With Tricuspid Valve Disease

Colorado Fetal Care Center | October 19, 2017

For families

  • Developing babies who have tricuspid valve disease with right atrial dysfunction often don't have good outcomes.
  • Our researchers have been studying tricuspid valve disease to better understand what happens in the right atrium of the heart to cause such poor outcomes.
  • Problems with the right atrium of the heart affect how the heart's ventricles work, which may be why these developing babies often don't survive.

For health professionals

  • Patients with fetal tricuspid valve disease with significant tricuspid valve regurgitation (rTVD) experience high mortality rates.
  • Our researchers studied right atrial dysfunction to determine its role in fetal circulation.
  • They found that right atrial dysfunction reduces ventricular filling and output. The reduced function is likely the reason for poor outcomes in this patient population.

Research background: Findings associated with fetal tricuspid valve disease

Fetal tricuspid valve disease with significant tricuspid valve regurgitation (rTVD), such as Ebstein’s anomaly and tricuspid valve dysplasia, is often associated with cardiovascular compromise. This can cause affected fetuses to develop hydrops fetalis or suffer sudden fetal death.

Although prenatal detection of tricuspid valve disease is increasing, overall perinatal mortality is still reported as high as 83 percent in some studies. Currently, researchers strive to fully define the pathophysiology of fetal tricuspid valve disease that leads to poor outcomes.

Adult and animal models have demonstrated the importance of atrial function on cardiac performance and it is believed that atrial function may be even more important before birth due to its integral role in fetal circulation. When compared to normal fetuses and those with right heart obstructive lesions like tricuspid atresia and pulmonary atresia/intact ventricular septum, the right atrium in fetuses with regurgitant tricuspid valve disease is very dilated.

This study is aimed at determining if there is an inherent difference in right atrial function between fetuses with rTVD compared to those with right heart obstructive lesions and healthy controls. The team hypothesized that right atrial function is altered in fetuses with rTVD but not in right heart obstruction, which could contribute to differences in outcomes.

Research methods: Doctors compare cases of fetal rTVD to those with right heart obstructive lesions and healthy controls

Researchers from three major tertiary institutions in North America, including Lisa Howley, MD, co-director of Fetal Cardiology at Children’s Hospital Colorado’s Colorado Fetal Care Center, reviewed all cases of fetal rTVD and right heart obstruction and compared them to a cohort of normal fetuses.

Researchers reviewed prenatal and postnatal records to collect clinical information including outcomes for both congenital heart disease groups (tricuspid valve disease and right heart obstruction) and for the control patients.

FIRST Study to use velocity vector imaging to examine fetal atrial function with and without right heart disease
THREE Major tertiary care institutions providing patient data

Data collection and measurements from prenatal examinations

An evaluation of the detailed prenatal echocardiographic examinations occurred, including anatomic assessment and Doppler investigation. Data collected included:

  • Severity of tricuspid regurgitation (TR)
  • Presence or absence of patency of pulmonary valve
  • Left ventricle ejection fraction

Right atrial velocity vector imaging (VVI)

Researchers measured the right atrial function parameters using offline commercially available software designed to evaluate the motion and mechanics of the myocardium.

Research results: Characteristics of the study groups

Infographic showing that of 34 fetuses with tricuspid valve disease and regurgitation (rTVD), 22 had Ebstein's anomaly and 12 had tricuspid valve dysplasia.
Infographic showing that of 40 fetuses with right heart obstruction, 15 had tricuspid atresia and 25 had pulmonary atresia and intact ventricular septum.
Inforgraphic that says Findings were compared with 79 singleton control fetuses.

Fetuses with rTVD had the largest right atrial size and the poorest atrial function. They also had the lowest velocity vector imaging measures of right atrial reservoir function, of right atrial filling and of right atrial emptying rates compared with right heart obstruction and control fetuses. The systolic function of the left ventricle was preserved in all groups. Increased right atrial dilation and a reduced right atrial emptying rate were associated with fetal or neonatal demise.

Clinical outcomes for tricuspid valve regurgitation and right heart obstructions groups

A: Clinical outcomes of the tricuspid valve regurgitation (rTVD) group

Infographic showing that of 34 patients with tricuspid valve disease, 22 had Ebstein's anomaly and 12 had tricuspid valve dysplasia

B: Clinical outcomes of the right heart obstruction (RHO) group 

Chart showing that of 40 patients with right heart obstruction, 25 had PA/IVS and 15 had tricuspid atresia.

PA/IVS is pulmonary atresia with intact ventricular septum and TOP is termination of pregnancy.

Research conclusions

Researchers found that patients with fetal rTVD experienced more severe right atrial dilation and dysfunction compared to patients with right heart obstruction and control groups. Right atrial dysfunction could be a key contributor to reduced ventricular filling and output, which may play a critical role in the rate of poor outcomes in patients with fetal rTVD.

Dr. Howley standing in a hallway at the hospital.

Research limitations

Limitations include the retrospective nature of the study. Not all patients completed clinical information so study authors were unable to determine the impact of tricuspid regurgitation and ventricular compliance on right atrial volume and function. Also during the study, researchers were unable to accurately quantify right atrial contribution to left ventricle filling.