No-Implant Interatrial Shunt for HFpEF: 6-Month Outcomes From Multicenter Pilot Feasibility Studies.

BACKGROUND: Most approaches to the creation of an interatrial shunt require placement of a permanent implant to maintain patency. OBJECTIVES: The goal of this study was to investigate the safety and efficacy of a no-implant interatrial shunt for patients with heart failure with preserved ejection fraction (HFpEF) and heart failure with mildly reduced ejection fraction (HFmrEF). METHODS: This was a multicenter, uncontrolled study of patients with HFpEF/HFmrEF and NYHA functional class ≥II, ejection fraction >40%, and pulmonary capillary wedge pressure (PCWP) during supine exercise ≥25 mm Hg with PCWP-to-right atrial gradient ≥5 mm Hg. Follow-up was through 6 months with imaging to assess shunt durability. RESULTS: A total of 28 patients were enrolled: mean age was 68 ± 9 years, and 68% were female. Baseline resting and peak exercise PCWP were 19 ± 7 mm Hg and 40 ± 11 mm Hg, respectively. All procedures displayed technical success with confirmation of left-to-right flow (shunt diameter 7.1 ± 0.9 mm). At 1 month, peak exercise PCWP decreased 5.4 ± 9.6 mm Hg (P = 0.011) with no change in right atrial pressure. There were no serious device or procedure-related adverse events through 6 months. Mean 6-minute walk distance increased 101 ± 71 meters (P < 0.001); Kansas City Cardiomyopathy Questionnaire Overall Summary Score increased 26 ± 19 points (P < 0.001); N-terminal pro-B-type natriuretic peptide decreased 372 ± 857 pg/mL (P = 0.018); and shunt patency was confirmed with unchanged diameter. CONCLUSIONS: In these feasibility studies of a no-implant interatrial shunt, HFpEF/HFmrEF shunts exhibited stability with favorable safety and early efficacy signals. The results show promise toward this new approach for treating patients with HFpEF/HFmrEF and an appropriate hemodynamic profile. (Evaluation of the Safety and Feasibility of a Percutaneously Created Interatrial Shunt to Alleviate Heart Failure Symptoms in Patients With Chronic Heart Failure and Preserved or Mid-Range Left Ventricular Ejection Fraction [ALLEVIATE-HF-1]; NCT04583527; Evaluation of the Safety and Effectiveness of a Percutaneously Created Interatrial Shunt to Alleviate Heart Failure Symptoms in Patients With Chronic Heart Failure and Preserved or Mid-Range Left Ventricular Ejection Fraction [ALLEVIATE-HF-2]; NCT04838353).

Feasibility of a No-Implant Approach to Interatrial Shunts: Preclinical and Early Clinical Studies.

Background: Heart failure with preserved ejection fraction represents a major unmet clinical need with limited treatment options. Recent device therapies under investigation have focused on decompression of the left atrium through an implantable interatrial shunt. Although these devices have shown favorable safety and efficacy signals, an implant is required to maintain shunt patency, which may increase the patient risk profile and complicate subsequent interventions requiring transseptal access. Methods: The Alleviant System is a no-implant approach to creating an interatrial shunt using radiofrequency energy to securely capture, excise, and extract a precise disk of tissue from the interatrial septum. Acute preclinical studies in healthy swine (n = 5) demonstrated the feasibility of the Alleviant System to repeatably create a 7 mm interatrial orifice with minimal collateral thermal effect and minimal platelet and fibrin deposition observed histologically. Results: Chronic animal studies (n = 9) were carried out to 30- and 60-day time points and exhibited sustained shunt patency with histology demonstrating completely healed margins, endothelialization, and no trauma to adjacent atrial tissue. Preliminary clinical safety and feasibility were validated in a first-in-human study in patients with heart failure with preserved ejection fraction (n = 15). All patients demonstrated shunt patency by transesophageal echocardiographic imaging at 1, 3, and 6 months, as well as cardiac computed tomography imaging at 6-month follow-up timepoints. Conclusions: Combined, these data support the safety and feasibility of a novel no-implant approach to creating an interatrial shunt using the Alleviant System. Continued follow-up and subsequent clinical studies are currently ongoing.