Atrial Mechanics in Heart Failure With Preserved Ejection Fraction: Effect of a No-Implant Interatrial Shunt.

Abstract

Background: The atria play an important role in the pathophysiology of heart failure with preserved ejection fraction. Decreased left atrial strain is associated with worse clinical outcomes. The impact of no-implant interatrial shunting on atrial structure and function has not been described.

Methods: We characterized the left atrial (LA) and right atrial strain-pressure relationship at rest and during exercise, before and after creation of a no-implant interatrial shunt. We included patients with New York Heart Association class II, III, or ambulatory IV heart failure with a left ventricular ejection fraction ≥40% and elevated LA wedge pressure during supine ergometry (≥25 mm Hg). Exercise hemodynamics and echocardiographic measurements were analyzed at baseline, 1 month and 6 months (echo only) following transcatheter, transeptal creation of a 7 mm no-implant interatrial shunt.

Results: A total of 33 patients were enrolled/included in the study. At 1 month, LA pressure at rest was significantly reduced from 19.7±7.0 to 17.2±5.0 mm Hg (P=0.044), and from 39.7±10.5 to 33.6±11.1 mm Hg (P=0.002) during exercise. Reductions in LA pressure were associated with a mean decrease of 55.4 mm Hg/W·kg in LA work (P<0.001). Echo measurements demonstrated significant improvements in LA reservoir strain of +4.0% (P=0.015) and +4.1% (P=0.046) at 1 and 6 months, respectively. Modest improvements were observed in LA conduit and contractile strain, with a similar overall trend in right atrial strain measurements. These findings were associated with a significant reduction in LA volumes and an increase in right atrial volume. There was no change in right atrial pressure or measures of right ventricular function.

Conclusions: Hemodynamic and strain assessment in patients with heart failure with preserved ejection fraction suggests that a no-implant interatrial shunt can significantly improve the pressure-function relationship of the LA.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04583527; URL: https://www.clinicaltrials.gov; Unique identifier: NCT04838353; URL: https://www.clinicaltrials.gov; Unique identifier: NCT05501652.