Case Report: Post-Total anomalous pulmonary venous connection pulmonary hypertension - novel treatment using sirolimus and atrial flow regulator implantation.

Objective: In patients who have undergone surgical repair of TAPVC and who develop treatment-resistant pulmonary vein stenosis and postcapillary pulmonary hypertension, pre-capillary pulmonary hypertension may also develop as a consequence of arterial remodelling. We present a 3-year-old boy with surgically corrected TAPVC in whom AFR 8   ×   5 was implanted using a 9F delivery system due to end-stage precapillary PH. Case report: In a male term newborn, obstructive supracardiac TAPVR was diagnosed, and he underwent surgical repair on the third day of life. At three months of age, he was hospitalised for respiratory distress, feeding intolerance, and early fatigability. He underwent re-operation using a sutureless repair technique with creation of an atrial septal defect (ASD). The postoperative course was complicated by left upper pulmonary venous (LUPV) obstruction, and multiple balloon venoplasties were performed. Hemodynamic and oximetric measurements were consistent with mixed PH. Sirolimus, losartan and bosentan therapy were initiated. Systemic infections complicated the in-hospital course. Due to prolonged dependence on invasive mechanical ventilation, tracheostomy was performed. Invasive haemodynamic assessment in the 3rd year of life revealed severe precapillary PH (mean PA pressure 98 mmHg, PVR 12. 8 Wu/m2, wedge 14 mmHg). At the same time, CT angiography showed no pulmonary vein obstructions and anastomosis between the LUPV and LLPV. A month after catheterisation, he was admitted to the ICU due to deterioration of his general condition and progression of PH (body weight 10 kg). Inhaled NO, along with high-dose milrinone, was initiated; despite a favourable clinical course, we decided to proceed with implantation of an atrial flow regulator (AFR). The intervention was performed on iNO and milrinone. ASD dilatation was performed using a Z-Med 2 balloon (10   ×   20 mm). During balloon insufflation, severe bradycardia with electromechanical dissociation was observed. Adrenaline infusion was initiated, and repeated boluses were administered. AFR 8   ×   5 was implanted via 9F delivery sheath. Echocardiography showed right ventricular unloading, reduced tricuspid regurgitation, correct device placement, and a right-to-left shunt. Hemodynamic stability was rapidly achieved, allowing discontinuation of inotropes and iloprost after six days. The patient was transitioned to home mechanical ventilation, with clinical conditions gradually improving and cyclic intravenous iloprost was initiated. Conclusion: The development of precapillary PH is a serious complication following TAPVR operation. The use of a pulmonary vasodilator and AFR implantation can facilitate RV unloading. The feasibility and clinical impact of AFR implantation via an undersized delivery system in paediatric end-stage PH are promising as a bridge to transplant.