P1265 A home for two: a case of a twin pregnancy complicated by twin-to-twin transfusion in a woman with a repaired total anomalous pulmonary venous connection

Abstract

Abstract BACKGROUND Total anomalous pulmonary venous connection (TAPVC) is a rare correctable congenital heart lesion. According to the modified World Health Organization classification (mWHO) of maternal cardiovascular risk, pregnant patients with successfully repaired TAPVC are at low cardiovascular risk (mWHO class I), but the risk rises to mWHO class III if left ventricular (LV) impairment and ventricular arrhythmias are present. CASE SUMMARY A 34 years old woman with corrected supracardiac TAPVC, pregnant with a spontaneous monochorionic diamniotic twin pregnancy (TP) complicated by twin-to-twin transfusion syndrome (TTTS) was referred to the cardiologist in preparation for fetoscopic laser coagulation (FLC). She was born with a TAPVC to the innominate vein associated with an atrial septal defect (ASD), repaired at the age of 3 months by anastomosing the PVC to the posterolateral wall of the left atrium and closure of the ASD with a pericardial patch. At follow up a few years later she developed asymptomatic mild LV dysfunction and alternating brady and tachyarrhythmias including non-sustained ventricular tachycardias (NSVT). At 17th weeks of gestation she presented mild dyspnoea (NYHA functional class II) and an alternance of sinus bradycardia, atrial fibrillation and NSVT. 2D echocardiography showed moderate LV dilatation and dysfunction (LVEF 47%). She was treated with loop-diuretics, but refused antiarrhythmic and anticoagulant therapy. At 19th weeks, TTTS was diagnosed and successful FLC of placental anastomoses was carried out. Symptomatic worsening of LV function and functional class developed in the ensuing weeks (NYHA III, LVEF 40%). Induction of foetal lung maturity with maternal administration of steroids was carried out at 28 weeks but stopped because of spontaneous preterm labour. After delivery, the arrhythmic burden increased to the point of requiring admission to the intensive care unit (ICU) where pacemaker implant was indicated, but refused by the patient. Diuretics and ACE-inhibitors were titrated, but no beta-blockers nor other antiarrhythmics could be started due to intermittent av block. At discharge, the patient was asymptomatic at rest and there were no clinical signs of heart failure. At 17 months of follow-up, she was still asymptomatic, though LV function remained poor. The 2 newborns were discharged after a stormy 4 months in the neonatal ICU and are still being treated for bronchopulmonary dysplasia and the sequels of intraventricular haemorrages. DISCUSSION We are not aware of other described twin pregnancies in repaired TAPVC with residual LV dysfunction and arrhythmia. As the haemodynamic load of twin pregnancy is more severe and the twin pregnancy itself at high risk both for prematurity and maternal cardiac deterioration, evaluation by a Specialist Multidisciplinary referral Unit should occur before conception especially in mNYHA class III and higher, as per current guidelines. Abstract P1265 Figure. Image 1