Use of Extracorporeal membrane oxygenation for Prevention of Right Heart Failure in High-Risk Patients with Suprasystemic Pulmonary Arterial Hypertension after Cardiac Surgery

Objectives: Due to the high risk of right heart failure (RHF), patients with congenital heart disease suffering from suprasystemic pulmonary arterial hypertension (PAH) are considered to be poor candidates for surgery. However, some may still be eligible for cardiac operations (e.g., Pott shunt, valve repair, and corrective surgery). Four patients are presented, who underwent different types of interventions and received preemptive extracorporeal membrane oxygenation (ECMO) support postoperatively to prevent RHF.

Methods: Patients age ranged from 1.5 to 27 years (body surface area = 0.37–1.61 m²; three females, one male). In patients 1 to 3, the diagnoses included (1) corrected IAA, (2) uncorrected TAC with Eisenmenger’s syndrome, and (3) PAPVR with Adams–Oliver’s syndrome. Preoperatively, these patients had a RV-EF of 42 ± 8%, a TAPSE of 13 ± 3 mm, and a BNP of 185 ± 4 pg/mL. In contrast, patient 4 presented decompensated global heart failure due to dilated cardiomyopathy with a RV-EF of 12% and a LV-EF of 15% (TAPSE = 2 mm, BNP = 2,270 pg/mL). All patients showed suprasystemic PAH (PVRI = 30 ± 13 WE × m², Rp/Rs range: 1.05–1.76, DPG = 45 ± 18 mm Hg, Qp/Qs range: 1.0–1.1). The RV-EDI measured by MRI was 142 ± 42 mL/m². Only patients 3 and 4 showed pulmonary vascular reactivity on NO or O₂ (decrease in PVRI by >50%). Patients 1 to 3 received either valve repair and/or corrective surgery in conjunction with a reversed Pott shunt. Patient 4 underwent heart transplantation (HTx).

Results: Length of ECMO support ranged from 3 to 6 days. In patients 1 to 3, initial ECMO flow was 46 ± 7% of calculated total cardiac output (=2.4 L/min/m²), following HTx it was 98%. Flow was then decreased by steps of 10 to 20% under control of the vital parameters (BP, CVP, HR, and SvO₂) and echocardiography (TAPSE, RV/LV-diameter ratio at end-systole). PAP was not routinely measured (only after HTx). All patients received NO (20–40 ppm), sildenafil (3 mg/kg/d), Ilomedin (2 ng/kg/min), milrinone, and noradrenaline. In patients 1 and 2, suprasystemic PAH persisted, but the RV was decompressed via a Pott shunt. In patients 3 and 4, systolic PAP/SAP ratio decreased to < 0.5. Length of mechanical ventilation ranged from 8 to 25 days. All patients were discharged from hospital and are still alive.

Conclusion: Preemptive partial ECMO support with a stepwise weaning process over days helps prevent postoperative RHF in high-risk patients. Preserved preoperative RV function, positive pulmonary vascular reactivity testing, and improvement in the RV working conditions by the cardiac intervention contribute to improved outcome.