Impact of pregnancy on the systemic right ventricle after a Mustard operation for transposition of the great arteries.

Objectives: We sought to determine the impact of pregnancy on the systemic right ventricle (RV) after a Mustard operation for transposition of the great arteries.
Background: Dysfunction of the RV remains a continuing problem after a Mustard operation. Concerns exist about the potentially deleterious effects of pregnancy on this ventricle.
Methods: The records of 16 women who completed 28 pregnancies were reviewed for clinical status, echocardiographic evaluation of RV dimensions, RV function, and tricuspid regurgitation (TR) before, during, and after pregnancy.
Results: Women were in New York Heart Association functional class I (n = 21) and II (n = 7) before pregnancy. The functional class deteriorated in six women, with no return to the pre-pregnancy level after delivery in two. Data on RV dimensions were available in 18 pregnancies, on RV function in 21, and on TR in 20. Before pregnancy, RV dilation was absent (n = 4), mild/moderate (n = 12), or severe (n = 2) and progressed in five women (31%), with no recovery in all patients at the last follow-up. Right ventricular systolic dysfunction was absent (n = 16), mild/moderate (n = 4), or severe (n = 1) before pregnancy and progressed in four women (25%), with no recovery in three cases. Tricuspid regurgitation was absent (n = 8), mild (n = 9), or moderate (n = 3) before pregnancy and deteriorated in eight women (50%), with no recovery in three patients.
Conclusions: Pregnancy after a Mustard operation is clinically well tolerated but carries a risk of RV dysfunction, which is sometimes irreversible.