Inclusion Criteria:

1. Signed and dated IRB approved study consent form prior to study related procedures

2. ≥ 18 years old

3. Chronic symptomatic Heart Failure (HF) documented by the following:

1. NYHA class II with a history of NYHA class > II; NYHA class III; or ambulatory
NYHA class IV AND

2. ≥ 1 HF hospital admission (with HF as the primary, or secondary diagnosis); or treatment with intravenous (IV) or intensification of oral diuresis for HF in a healthcare facility (emergency department/acute care facility) within the 12
months prior to study entry; OR an NT-pro BNP value > 150 pg./ml in normal sinus rhythm, > 450 pg./ml in atrial fibrillation, or a BNP value > 50 pg./ml in normal
sinus rhythm, > 150 pg./ml in atrial fibrillation within the past 6 months prior to study entry.

4. In the judgment of the investigator, subject is on stable Guideline Directed Medical Therapy (GDMT) for heart failure and management of potential comorbidities according
to current ACCF/AHA Guidelines and that is expected to be maintained without change for 3 months

5. At rest: elevated LAP or PCWP pressure of > 15 mmHg and LAP (or PCWP) exceeds right atrial pressure (RAP) by > 5 mmHg AND/OR during supine ergometer exercise stress test, as measured at end-expiration, elevated LA (or PCWP) pressure of > 25 mmHg and LA (or PCWP) exceeds right atrial pressure (RAP) by > 10 mmHg

6. Willing to attend study follow-up assessments for up to 5 years

Inclusion Criteria for Cohort B, Heart Failure with Pulmonary Vascular Disease only:

1. Pulmonary Vascular Resistance (PVR) > 3.0 and ≤ 8.0 Wood Units at rest

2. Mean Pulmonary Artery Pressure (mPAP) ≥ 25 mmHg at rest AND

3. If baseline PVR is > 4.0, must show successful reversibility of PH under a resting Sodium Nitroprusside* challenge where success is defined as a lowering of the PVR to a level ≤ 4.0 Wood Units while maintaining a Systolic Blood Pressure ≥ 90 mmHg.

- Equivalent vasodilator agent (e.g., nitric oxide) may be used as deemed appropriate per hospital practice

Exclusion Criteria:

1. Severe heart failure defined as one or more of the below:

1. ACC/AHA/ESC Stage D heart failure, non-ambulatory NYHA Class IV HF;
2. If BMI < 30, Cardiac index < 2.0 L/min/m^2;
3. If BMI ≥ 30, cardiac index < 1.8 L/min/m^2;
4. Inotropic infusion (continuous or intermittent) within the past 6 months;
5. Patient is on the cardiac transplant waiting list;
6. LVEF < 20%.

2. Presence of significant valve disease defined by the site cardiologist as:

1. Mitral valve regurgitation defined as grade > 3+ MR or > moderate MS;'
2. Tricuspid valve regurgitation defined as grade > 2+ TR;
3. Aortic valve disease defined as > 2+ AR or > moderate AS.

3. MI and/or any therapeutic invasive, non-valvular cardiac procedure within past 3 months or current indication for coronary revascularization

4. Surgical valve repair or replacement within the past 12 months; Transcatheter valve repair or replacement within the past 6 months.

5. Cardiac Resynchronization Therapy initiated, stroke or transient ischemic attack (TIA) within the past 6 months

6. Hemodynamic instability within 30 days of scheduled implant procedure

7. Patient requiring surgery under general anesthesia for any reason within 30 days of scheduled implant procedure

8. Clinically diagnosed hypertrophic obstructive cardiomyopathy, constrictive pericarditis or other infiltrative cardiomyopathy (e.g., hemochromatosis, sarcoidosis)

9. Has renal insufficiency as determined by creatinine (S-Cr) level > 2.5 mg/dL or estimated-GFR < 25ml/min/1.73 m^2 by CKD-Epi equation; or currently requiring dialysis

10. Significant hepatic impairment defined as 3 × upper limit of normal of transaminases total bilirubin, or alkaline phosphatase

11. Performance of the 6 minute walk test with a distance < 50m OR > 600m

12. Subject is contraindicated to receive either dual antiplatelet therapy or warfarin (analogue); or has a documented coagulopathy

13. Known hypersensitivity to anticoagulation therapy or contrast agent, which cannot be adequately medicated

14. Known hypersensitivity to Nickel and/or Tantalum

15. In the judgment of the investigator, life expectancy < 12 months for noncardiovascular reasons

16. In the opinion of the investigator, the subject is not an appropriate candidate for the study

17. Anatomy (including implantable devices) that is not compatible with the Edwards Transcatheter Atrial Shunt System

18. Active endocarditis or infection within 3 months of scheduled implant procedure 
19. Currently participating (e.g., undergoing trial specific exams/treatment/procedures) in an investigational drug or device study. Note: trials requiring extended follow-up
for products that were investigational but have since become commercially available are not considered investigational trials.

20. Patient is a current intravenous recreational drug user

21. Positive serum pregnancy test in female subjects of child-bearing potential or nursing mothers or planning on becoming pregnant during the duration of the trial

22. Patient is under guardianship

23. Known pre-existing shunting, determined to be clinically significant by the investigator

24. (Not applicable to Cohort B) Right ventricular dysfunction, defined by the site cardiologist as:

1. More than mild RV dysfunction as estimated by TTE; OR
2. TAPSE <1.4 cm; OR
3. RV size ≥ LV size as estimated by TTE; OR
4. Echocardiographic or clinical evidence of congestive hepatopathy.

25. Evidence of pulmonary vascular disease with PVR >3.0 Wood units

Exclusion Criteria for Cohort B, Heart Failure with Pulmonary Vascular Disease only:

1. Propensity for increased Right ventricular dysfunction, defined by the site cardiologist as:

1. More than moderate RV dysfunction as estimated by TTE; OR
2. TAPSE <1.2 cm; OR
3. RV size ≥ LV size as estimated by TTE; OR
4. Mean Right Atrial Pressure (RAP) > 18 mm Hg; OR
5. Echocardiographic or clinical evidence of congestive hepatopathy.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Eligibility last updated 11/2/23. Questions regarding updates should be directed to the study team contact.