When to Do It from the Front: Surgical Closure of a Patent Ductus Arteriosus in a Patient with Alpha-actin2 Mutation

Objectives: Alpha-actin is an important contractile protein in vascular smooth muscle cells (SMCs). SMCs are found in walls of arteries and hollow visceral organs as well as in lacrimal ducts, hair follicles and the iris. Mutations in the most abundant form, α-actin2 (ACTA2), result in fixed dilated pupils, large dilated persistent ductus arteriosus and pulmonary hypertension. Surgical closure of a patent ductus arteriosus (PDA) in neonates, routinely performed via lateral thoracotomy, may not be advisable in patients ACTA2-mutations. We present the case of a patient referred to our institution for a giant arterial duct and pulmonary hypertension.

Case: The 3 months old, female patient presented with respiratory distress and decreased oxygen saturations 4 weeks after normal birth. Due to increasing pulmonary hypertension and hypercapnia ventilation and intravenous nitrogen therapy were needed. Initially, an infectious cause was suspected and antibiotic treatment was established. Echocardiography showed a huge PDA of 6x12 mm. In combination with mydriasis of both pupils genetic analysis was performed and an ACTA2- gene mutation (missense mutation R179H) was found. After interdisciplinary discussion an approach via left thoracotomy was chosen. After exposure the duct showed a diameter of 15 mm with no neck to perform ligature. Closure via lateral thoracotomy seemed too dangerous and we converted to median sternotomy. PDA closure finally was achieved with help of extracorporeal circulation in hypothermic circulatory arrest (18°C). After division of the PDA, a rim of only ~2 mm ductal tissue was found and resected. Subsequently, a patch plasty (CorMatrix Cardiovascular, Roswell, USA) of the aortic isthmus and pulmonary bifurcation was performed. The postoperative course was uneventful and the patient was well with no signs of pulmonary hypertension four weeks after the operation.

Conclusion: In patients with ACTA2-mutation surgical approach via median sternotomy is advisable. Not only the diameter of the PDA itself, but also the fragility of the abnormal tissue renders a lateral thoracotomy risky. Deep hypothermic circulatory arrest with patch augmentation of the large arteries is mandatory in cases of a massively dilated duct without neck or very short course.