Update on Atrial Shunt Therapy for Treatment of Heart Failure.

Heart failure with preserved ejection fraction is associated with elevated left atrial pressure during exercise. Sodium-glucose cotransporter-2 inhibitors have demonstrated the evidence of benefit in heart failure with preserved ejection fraction, but even with this treatment, heart failure hospitalizations remain high, and improvements in quality of life scores are modest. Thus, there is growing interest in nonpharmacological methods of limiting the rise in left atrial pressure during exertion. Creation of an interatrial shunt (IAS) may unload the left heart during exercise. Multiple implant or nonimplant IAS procedures are under investigation. Implantation of the most studied device results in 3 to 5 mm Hg decreases in pulmonary capillary wedge pressure during exercise, no increase in incidence of stroke, stable increases in Qp/Qs (1.2-1.3), and mild right heart enlargement without change in function out to at least a year after treatment. The findings from the first large randomized controlled trial of an atrial shunt have recently been published. For the population as a whole, implantation of the atrial shunt device appeared to be safe but did not provide clinical benefit. However, prespecified and post-hoc analyses have demonstrated that men, patients with larger right atrial volumes, and those with pulmonary artery systolic pressure >70 mm Hg at 20 W exercise had worse outcomes with IAS therapy, whereas those with peak exercise pulmonary vascular resistance <1.74 Wood units and absence of a pacemaker represented a potential responder group. Here, we summarize the results of the published data and the current IAS therapies under investigation. We also highlight unanswered questions in this field of inquiry.