Prenatal heart block screening in mothers with SSA/SSB autoantibodies: Targeted screening protocol is a cost-effective strategy

Objective: Maternal anti-Ro/SSA and anti-La/SSB antibodies can lead to fetal complete heart block (CHB). Current guidelines recommend weekly echocardiographic screening between 16 and 28 weeks gestation. Given the cost of screening and the rarity of conduction abnormalities in fetuses of mothers with low anti-Ro levels (<50 U/mL), we sought to identify a strategy that optimizes resource utilization. Design: Decision analysis cost-utility modeling was performed for three screening paradigms: “standard screening” (SS) in which mid-gestation mothers are screened weekly, “limited screening” (LS) in which fetal echocardiograms are avoided unless the fetus develops bradycardia, and “targeted screening by maternal antibody level” (TS) in which only high anti-Ro values warrant weekly screening. A systematic review of existing literature and institutional cost data were used to define model inputs. Results: The average cost of LS, TS, and SS was $8566, $11 038, and $23 279, respectively. SS was cost-ineffective with an incremental cost-effectiveness ratio (ICER) of $322 756 while TS was cost-effective with an ICER of $43 445. Conclusion: While the efficacy of fetal intervention for first or second degree AV block remains unclear, this analysis supports utilizing antibody levels to stratify this population for optimized surveillance for CHB. SS is cost-ineffective and results in resource overutilization.