Cardiac magnetic resonance imaging characteristics and pregnancy outcomes in women with Mustard palliation for complete transposition of the great arteries

BACKGROUND: Women with transposition of the great arteries (TGA) following atrial redirection surgery are at risk of pregnancy-associated arrhythmia and heart failure. The cardiovascular magnetic resonance imaging (CMR) characteristics of these women and the relationship of CMR findings to pregnancy outcomes have not been described. METHODS: We included 17 women with atrial redirection surgery and CMR within 2 years of delivery. RESULTS: All women were asymptomatic at baseline (New York Heart Association Class 1). CMR studies were completed pre-pregnancy in 3, antepartum/peripartum in 2, and postpartum in 12 women. Three women (3/17, 18%) experienced major cardiovascular events related to pregnancy: cardiac arrest (n = 1) and symptomatic atrial arrhythmia (n = 2). Median gestational age at delivery was 38 weeks (24–39 weeks) and birth weight was 2770 g (2195–3720 g). Complications were seen in 3 offspring (3/17, 18%): death (n = 1) and prematurity (n = 2). CMR characteristics included median right ventricular end diastolic volume 119 mL/m(2) (range 85–214 mL/m(2)) and median right ventricular ejection fraction (RVEF) 37% (range 30–51%). All women with cardiovascular complications had an RVEF < 35% (range 32–34%). The association between RVEF < 35% and cardiovascular complications trended towards statistical significance (p = 0.05). No statistically significant differences in CMR measurements were found between those with and without neonatal complications. CONCLUSIONS: While the majority of women in this cohort had successful outcomes following pregnancy, important cardiovascular complications were seen in a significant minority, all of whom had an RVEF < 35%. The preliminary findings of our study provide impetus for a larger prospective study to evaluate the prognostic role of CMR in pregnant women with atrial redirection surgery.