Outcome of Antibody-Mediated Fetal Heart Disease With Standardized AntiInflammatory Transplacental Treatment

BACKGROUND: Transplacental fetal treatment of immune-mediated fetal heart disease, including third-degree atrioventricular block (AVB III) and endocardial fibroelastosis, is controversial. METHODS AND RESULTS: To study the impact of routine transplacental fetal treatment, we reviewed 130 consecutive cases, including 108 with AVB III and 22 with other diagnoses (first-degree/second-degree atrioventricular block [n=10]; isolated endocardial fibroelastosis [n=9]; atrial bradycardia [n=3]). Dexamethasone was started at a median of 22.4 gestational weeks. Additional treatment for AVB III included the use of a β-agonist (n=47) and intravenous immune globulin (n=34). Fetal, neonatal, and 1-year survival rates with AVB III were 95%, 93%, and 89%, respectively. Variables present at diagnosis that were associated with perinatal death included an atrial rate <90 beats per minute (odds ratio [OR], 258.4; 95% CI, 11.5–5798.9; P<0.001), endocardial fibroelastosis (OR, 28.9; 95% CI, 1.6–521.7; P<0.001), fetal hydrops (OR, 25.5; 95% CI, 4.4–145.3; P<0.001), ventricular dysfunction (OR, 7.6; 95% CI, 1.5–39.4; P=0.03), and a ventricular rate <45 beats per minute (OR, 12.9; 95% CI, 1.75–95.8; P=0.034). At a median follow-up of 5.9 years, 85 of 100 neonatal survivors were paced, and 1 required a heart transplant for dilated cardiomyopathy. Cotreatment with intravenous immune globulin was used in 16 of 22 fetuses with diagnoses other than AVB III. Neonatal and 1-year survival rates of this cohort were 100% and 95%, respectively. At a median age of 3.1 years, 5 of 21 children were paced, and all had normal ventricular function. CONCLUSIONS: Our findings reveal a low risk of perinatal mortality and postnatal cardiomyopathy in fetuses that received transplacental dexamethasone±other treatment from the time of a new diagnosis of immune-mediated heart disease.