Comprehensive Investigation of Latent Pulmonary Vascular Disease

Transcatheter atrial shunt therapies, designed to dynamically lower left atrial (LA) pressure by shunting blood into the larger reservoir of the right atrium and central veins, have been developed as a novel treatment for heart failure (HF) over the past 10+ years. Several atrial shunt devices and procedures are currently in development with several pivotal randomized clinical trials (RCT) underway; however, only 2 sham-controlled RCT (both with the Atrial Shunt Device [Corvia Medical] in HF with EF ≥ 40%) have been reported thus far; a mechanistic RCT (n = 44) that demonstrated a reduction in exercise LA pressure at 1 month and a pivotal RCT (n = 626) that was neutral with no difference in outcomes or health status between shunt and sham groups. Subsequent analyses of the single completed pivotal RCT found that peak exercise pulmonary vascular resistance <1.74 WU plus the absence of a cardiac rhythm management device identified a responder group that benefited from LA unloading with atrial shunt implantation, a finding that is currently being confirmed in a follow-up RCT. Here we provide a comprehensive review of the field of atrial shunt therapeutics with a description of the following: (1) current HF treatment; (2) rationale and history of atrial shunt development; (3) design of and accumulated evidence for the various atrial shunt devices and procedures under investigation; (4) unanswered questions in the field; and (5) future considerations. Atrial shunts represent a potential innovative therapeutic for HF but the optimal design/approach and phenotype of HF most likely to benefit are yet to be determined.