The Role of Shunt Occlusion During Extracorporeal Life Support

Introduction: The current recommendation for systemic to pulmonary artery shunt (SPS) patients requiring extracorporeal life support (ECLS) is to keep the shunt open, maintaining a higher pump flow. The practice in our center is to totally occlude the shunt while on ECLS, and we are presenting the outcome of this strategy. Methods: This is a retrospective analysis of patients who underwent SPS for cyanotic congenital heart disease with decreased pulmonary blood flow and required postoperative ECLS between January 2016 and December 2020. ECLS indication was excessive pulmonary blood flow, leading to either refractory low cardiac output syndrome (LCOS) or cardiac arrest. All patients had their shunts totally occluded soon after ECLS establishment. Results: Of the 27 SPS patients who needed postoperative ECLS (13 refractory LCOS, 14 extracorporeal cardiopulmonary resuscitation), wherein the strategy of occluding the shunt on ECLS initiation was followed, 16 (59.3 %) survived ECLS weaning and eight (29.6%) survived to discharge. Conclusion: Increased flow to maintain systemic circulation for a SPS patient while on ECLS is an accepted strategy, but it should not be applied universally. A large subset of SPS patients, who require ECLS either due to cardiac arrest or refractory LCOS due to excessive pulmonary flow, might benefit from complete occlusion of the shunt soon after commencement of ECLS, especially in cases with frank pulmonary edema or haemorrhage in the pre-ECLS period. A prospective randomized trial could be ethically justified for the subset of patients receiving ECLS for the indication of excessive pulmonary blood flow.