Identical twin baby girls with twin-to-twin transfusion syndrome which means the babies had some shared blood vessels in their shared placenta. Were delivered 3 months early (28 wks gestation) due to concerns that the smaller "A" twin was not moving normally. The larger "B" twin was known to have a serious heart defect with moderate narrowing of two of her heart valves.

At birth, the larger twin "B" (Jocelyn Clymer) weighed just 2 1/2 pounds. Her heart problem was serious and the aortic valve was so narrowed (called critical aortic stenosis) that her heart chamber could not generate a high enough pressure to pump enough blood across the valve, leading to poor blood circulation.

Because of her extremely small size, treatment of her critically narrowed valve was a challenge. She was far too small to have conventional heart surgery. She needed to have a balloon dilation procedure to help open her tightly obstructed aortic valve, but the blood vessels in the upper leg, which are typically used for vascular access to perform a balloon dilation procedure, were much too small in this baby to accommodate the balloon dilation catheter so a very small adult coronary balloon was used.

The solution to the problem was to perform combined surgery (Dr Steve Leonard) and heart catheterization (Dr Dave Miller) in what is termed a hybrid procedure. The baby was transferred to the Cath lab where Dr Leonard prepared the catheter access site by making a small incision in the neck to expose the carotid artery. Dr Miller was able to advance the balloon dilation catheter from the carotid artery directly across the tightly obstructed heart valve so that the balloon could be inflated, opening the narrowed valve in the process. The balloon was removed and then Dr Leonard repaired the incision in the artery before closing the skin incision.

The baby's circulation improved immediately and her recovery was uneventful.

This was the smallest baby to undergo treatment of critical aortic stenosis at Rocky Mountain Hospital for Children (more than 1 pound smaller than the next largest baby ever done at Rocky Mountain Hospital for Children) and one of the smallest in the country. The hybrid approach with surgery and catheterization techniques made the procedure possible for such a small baby.