Interatrial Shunt Devices in Heart Failure: A Therapy in Search of the Right Patient

Heart failure with preserved or mildly reduced ejection fraction (HFpEF/HFmrEF) accounts for approximately half of the global heart failure burden and remains a syndrome with limited device-based therapeutic options. It is often characterized by a disproportionate rise in left-sided filling pressure during exercise. Interatrial shunt devices (IASDs) aim to reduce left atrial pressure through controlled left-to-right atrial communication. We performed a structured narrative review of mechanistic studies, early feasibility cohorts, randomized trials, meta-analyses, and ongoing studies indexed through to August 2026. Early proof-of-concept studies consistently demonstrated technical feasibility, durable patency, and favorable hemodynamic effects, particularly through reductions in pulmonary capillary wedge pressure (PCWP), often accompanied by improved functional status. However, larger sham-controlled randomized trials failed to show consistent overall benefit in unselected populations. Recent mechanistic and observational data indicate that pulmonary vascular reserve, right ventricular-pulmonary arterial coupling, rhythm-device status, and device design may affect benefits and harms. Latent pulmonary vascular disease and impaired right-heart reserve may identify patients poorly suited for shunt implantation, whereas carefully selected, promising phenotypes remain under prospective study. IASDs should therefore remain investigational. Future trials should use exercise hemodynamics and validated noninvasive markers to prospectively define responders, assess device-specific effects, and reconcile physiological unloading with clinical outcomes.