Successful biventricular repair following in-utero balloon dilation of critical aortic stenosis

Critical aortic stenosis (AS) with reversed aortic arch flow in the mid-trimester fetus usually evolves into hypoplastic left heart syndrome (HLHS)

We report two cases of successful biventricular repair following in-utero valvuloplasty. Case 1 presented at 28 weeks with a grossly dilated poorly contracting left ventricle (LV), signs of endocardial fibroelastosis, mild mitral regurgitation (MR) (2,9 m/s), critical AS (1,7 m/s), reversed flow in the aortic arch and ascites. Transabdominal percutaneous valvuloplasty resulted in antegrade flow in the aortic arch, ascites disappeared within 7 days. Until delivery at 35 weeks MR velocity increased to 4,5 m/s, aortic velocity to 3,9 m/s which was attributed to improved ventricular performance. Postnatal aortic valvuloplasty was unsuccessful in reducing the gradient, so a neonatal Ross-Konno procedure was carried out. At discharge there was normal LV size and function. Case 2 had almost aortic atresia (no measurable gradient) and a dysplastic mitral valve with moderate MR (4,8 m/s) but no ascites. Balloon dilation was performed at 33 weeks followed by antegrade aortic arch flow, trivial AR, a residual gradient of 36 mmHg and improved LV shortening. Valvuloplasty after delivery at 38 weeks again could not reduce the gradient, a Ross-Konno procedure with mitral valve repair was successful in establishing a biventricular circulation with good LV function.

Conclusions: These two cases confirm that in critical AS timely in-utero aortic valvuloplasty is able to improve left ventricular performance and fetal hemodynamics in a way that the likelihood of a postnatal biventricular repair is increased.