Early intertwin differences in myocardial performance during the twin-to-twin transfusion syndrome

Area of Science:

• Cardiology
• Fetal Medicine
• Perinatology

Background:

• Twin-to-twin transfusion syndrome (TTTS) is increasingly linked to pressure overload causing recipient twin cardiomyopathy.
• Cardiac dysfunction may be an early indicator of TTTS.
• Distinguishing TTTS from intrauterine growth restriction (IUGR) is crucial for timely intervention.

Purpose of the Study:

• To investigate early intertwin differences in myocardial function in TTTS.
• To determine if these differences can differentiate TTTS from IUGR.

Main Methods:

• Fetal echocardiography was performed on twins with TTTS (n=21) and IUGR (n=11).
• Eight echocardiographic variables were analyzed, focusing on cardiac dimensions and Doppler parameters.
• Myocardial Performance Indices (MPI) were calculated for both ventricles.

Main Results:

• No significant differences were found in cardiothoracic ratio or umbilical/cerebral artery Doppler indices between TTTS and IUGR groups.
• Ventricular septal thickness differed but was not associated with either condition.
• Recipient twins in TTTS showed higher left ventricular shortening fraction and elevated MPI due to prolonged isovolumic periods, primarily during relaxation.
• Specific changes in LV and RV MPI thresholds identified TTTS with 75% sensitivity and 9% false-positive rate.

Conclusions:

• Diastolic dysfunction observed in TTTS supports the pressure-overload hypothesis.
• Intertwin MPI assessment is a valuable tool for early differential diagnosis between TTTS and IUGR.