Predicted versus observed outcomes in the ALT-FLOW early feasibility study

Area of Science:

• Cardiology
• Medical Devices
• Heart Failure Research

Background:

• The clinical outcome benefits of the APTURE left atrial-to-coronary sinus shunt in heart failure with preserved ejection fraction (HFpEF) are not well-established.
• Hemodynamic and symptomatic improvements require validation through clinical outcome data.

Purpose of the Study:

• To evaluate the clinical outcome benefits of the APTURE shunt in HFpEF patients.
• To compare observed mortality and heart failure hospitalization (HFH) rates before and after APTURE implantation.

Main Methods:

• Post hoc analysis of ALT-FLOW EFS patients who received APTURE implantation.
• Comparison of Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) score-predicted 1-year mortality with observed mortality.
• Analysis of heart failure hospitalization (HFH) rates pre- and post-implantation.
• Stratification by sodium-glucose cotransporter 2 inhibitor (SGLT2i) use and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels.

Main Results:

• Observed 1-year survival (94.7%) was significantly higher than MAGGIC-predicted mortality (87.0%; P=0.04).
• Heart failure hospitalizations (HFH) decreased significantly post-implantation (37.9% to 9.6%; P<0.0001), with event rates dropping from 0.61 to 0.21 per patient-year.
• Survival benefit was consistent across SGLT2i subgroups.

Conclusions:

• APTURE implantation in HFpEF patients resulted in lower-than-predicted 1-year mortality and reduced HFH rates.
• These findings are hypothesis-generating and warrant confirmation in the upcoming randomized ALT-FLOW II trial.