Long-term animal model of venovenous extracorporeal membrane oxygenation with atrial septal defect as a bridge to lung transplantation

Percutaneous Transseptal Extracorporeal Membrane Oxygenation to Rescue a Failing Right Ventricle in an Animal Model

OBJECTIVE

We tested the feasibility and effectiveness of a percutaneous atrial transseptal extracorporeal membrane oxygenation (ECMO) cannulation strategy in a right ventricular failure (RVF) model.

METHODS

We performed 4 nonsurvival porcine experiments. Percutaneous transseptal access was achieved using a steerable introducer. For guidance, we used fluoroscopy, transesophageal echocardiogram (TEE), and intracardiac echocardiography (ICE). A ProtekDuo rapid deployment cannula (LivaNova, London, UK) was advanced across the septum into the left atrium by 2 to 3 cm. Pulmonary hypertension (PH) was induced by partially clamping the pulmonary artery. ECMO flow was cycled from high (2 to 3 L/min) to low (0.2 to 0.3 L/min) over 2 to 3 hours.

RESULTS

Transseptal access using TEE and fluoroscopy was successful in 1 animal and unsuccessful in 1 animal. ICE provided optimal visualization for the remaining 2 animals. Mean arterial pressure (MAP) was associated immediately and consistently with high versus low ECMO flow rate (mean difference: 29 ± 3.1 mm Hg, P = 0.004) but was not restored to baseline values. RV pressure values were dynamic. Given time to equilibrate, mean RV pressure was restored to a baseline level.

CONCLUSIONS

Percutaneous right atrium to left atrium transseptal cannulation relieved PH-RVF. MAP was restored to a viable level, and mean RV pressure was restored to a baseline level. Transseptal ECMO shows promise as a cannulation strategy to bridge patients with PH-RVF to lung transplant.

Use of venous-venous extracorporeal membrane oxygenation in the treatment of postpartum pulmonary hypertension crisis

The incidence of heart disease in pregnancy ranges from 0.5% to 3.0% and is regarded as one of the top three causes of maternal death. The mortality rate of patients with pulmonary hypertension and Eisenmenger syndrome is as high as 16.7%-50%. Changes in haemodynamics during pregnancy and childbirth increase the burden on the heart, and induced pulmonary hypertension crisis is one of the main causes of maternal death. Extracorporeal Membrane Oxygenation (ECMO) is the last-resort treatment strategy to treat patients with pulmonary hypertension crisis. We report a ventricular septal defect in a pregnant woman with pulmonary hypertension and Eisenmenger's syndrome, which is a postpartum pulmonary hypertension crisis that leads to respiratory and circulatory disorders. The patient was successfully treated with venous-venous extracorporeal membrane oxygenation.

Advanced Surgical and Percutaneous Approaches to Pulmonary Vascular Disease

Despite progress in modern medical therapy, pulmonary hypertension remains an unremitting disease. Once severe or refractory to medical therapy, advanced percutaneous and surgical interventions can palliate right ventricular overload, bridge to transplantation, and overall extend a patient's course. These approaches include atrial septostomy, Potts shunt, and extracorporeal life support. Bilateral lung transplantation is the ultimate treatment for eligible patients, although the need for suitable lungs continues to outpace availability. Measures such as ex vivo lung perfusion are ongoing to expand donor lung availability, increase rates of transplant, and decrease waitlist mortality.

Venovenous extracorporeal membrane oxygenation in patients with atrial septal defects

Two patients presented in profound respiratory distress unresponsive to maximal support and were placed on venovenous ECMO. Subsequently, both were found to have a patent foramen ovale and high pulmonary artery pressures, resulting in a right to left shunt. Both patients had a better than expected response to ECMO, likely related to their shunts allowing oxygenated blood to bypass the high pulmonary artery pressures and go directly to the left heart. Both patients were successfully weaned from ECMO and discharged to home in good condition.