Refractory hypoxemia following mitral valve edge-to-edge repair: why is it so refractory?

) ruled out common pulmonary causes. Postoperative transthoracic echocardiography (TTE) revealed a right-to-left shunt via an iASD, which was promptly closed percutaneously, resulting in rapid resolution of hypoxemia. This report highlights that severe hypoxemia following successful TEER should trigger a suspicion of a RLS, especially in patients receiving mechanical ventilation with positive end-expiratory pressure (PEEP) or anemia. Early recognition and consideration of defect closure is essential when hypoxemia is refractory to conventional ventilatory maneuvers.