Photo Credit: ChaNaWiT

Interatrial shunts have a future in patients with HFrEF. However the Ventura Interatrial shunt device would have to be carefully considered in patients with HFpEF.

Pulmonary hypertension conditions often complicate heart failure with reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF). In a recent podcast episode, Physician’s Weekly board member Alex McDonald, MD, spoke with Gregg Stone, MD, about the RELIEVE-HF randomized clinical trial, designed to evaluate the safety and efficacy of treating patients with HF with an interatrial shunt.

Dr. Stone: Placement of the Ventura Interatrial shunt device was safe in a very sick population with HF but did not show a signal for effectiveness across the spectrum of left ventricular ejection fractions.

In those with baseline left ventricular ejection fraction under or equal to 40%, the shunt yielded a significant benefit, with nearly 50% reduction in cardiovascular AEs (HF hospitalizations, all cause death, LVAD, and transplant). Whereas in patients with left ventricular ejection fraction over 40%, we saw clear evidence of harm—in particular, increased HF hospitalizations and tripled mortality.

Interatrial shunts have a real future in patients with HFrEF. However, if used at all, this shunt would have to be carefully considered in patients with HFpEF.

PW: What do these findings suggest about the pathophysiological differences between HFrEF and HFpEF?

The two conditions share increased left atrial pressure (the median left atrial pressure at baseline was 16 mmHg). However, these conditions are very different regarding the size of cardiac structures. In HFrEF, the left ventricle is very weak and dilated, but in HFpEF, the left and right ventricle sizes are normal, and the heart is stiff or non-compliant.

In patients with HFrEF, the heart accommodated the increased blood flow from the left to the right atrium. The left atrial pressure went down, the left ventricle got smaller, there was less pulmonary venous congestion, and the patient got better. In contrast, in patients with HFpEF and stiff hearts, there was nowhere for that extra fluid to go.

This trial shows potential tremendous benefits for patients with HFrEF who have significant ongoing clinical needs. The shunt we tested had a specific design with a specific orifice diameter and shunt flow rate, but there are many other types out there. Now that we’ve identified the patient population that can benefit most, I expect to see new clinical trials of various interatrial shunts.