Survival to Hospital Discharge in the Fetus With Moderate to Severe Mitral Regurgitation Either in Isolation or in Combination With Aortic Valve Stenosis or Atresia, a Fetal Heart Society Collaborative Study.

BACKGROUND

Case series report high mortality after fetal diagnosis of moderate to severe mitral regurgitation in combination with left atrial dilation, hydrops, or restrictive atrial septum. However, overall outcomes and specific high-risk features remain unclear.

METHODS

We performed a multicenter retrospective cohort study of fetuses with ≥moderate mitral regurgitation and normal cardiac connections evaluated January 1, 2005 to January 31, 2016. Fetuses undergoing fetal cardiac intervention (FCI) were described separately. We assessed associations between fetal echocardiographic features and discharge mortality using mixed logistic regression and classification and regression tree modeling, stratified by studies performed <28 and ≥28 weeks gestational age (GA).

RESULTS

Of 67 fetuses, 96% had aortic valve stenosis or atresia. Among the non-FCI group, fetal and discharge mortality was 10% (5/51) and 55% (28/51), respectively. For echocardiograms performed <28 weeks GA, only restrictive atrial septum (odds ratio [OR], 49.6 [95% CI, 5.6-437.5]) and earlier GA at referral (OR 0.72 per increasing week GA [95% CI 0.54-0.96]) remained associated in multivariable analysis. For those ≥28 weeks GA, in multivariable analysis, left atrial dilation (OR, 12.41 [95% CI, 2.19-70.33]) and lower ascending aortic Z score (OR per 1 unit increase, 0.61 [95% CI, 0.39-0.94]) remained in the model. By classification and regression tree modeling, left atrial dilation, restrictive atrial septum, and ascending aortic Z score <-1.3 were the key discriminators between survivors and nonsurvivors. Most FCIs were aortic valvuloplasty (13/16). Discharge mortality among FCI fetuses was 38%, not significantly different from non-FCI once adjusting for mitral regurgitation and LA dilation.

CONCLUSIONS

Fetal ≥moderate MsR is associated with high mortality. Left atrial dilation, restrictive atrial septum, and smaller ascending aorta confer highest risk for mortality.