Interatrial Shunt Promising for Heart Failure With Preserved Ejection Fraction

November 17, 2016

NEW ORLEANS, LA — For patients with heart failure with preserved ejection fraction, implantation of an interatrial shunt device appeared to be safe and was associated with clinical and hemodynamic improvements sustained for 1 year, in a new clinical study[1].

The 1-year results from the REDUCE LAP HF study was presented at the American Heart Association 2016 Scientific Sessions this week.

Dr David Kaye

In his presentation, Dr David Kaye (Alfred Hospital, Melbourne, Australia) concluded: "Taken together, this study provides the longest experience with an interatrial shunt device specifically developed for the management of heart failure with preserved ejection fraction and provides additional longitudinal support for the safety and efficacy of this approach."

Study discussant Dr Nancy Sweitzer (Sarver Heart Center, University of Arizona, Tucson) said the 12-month results were reassuring on safety and the efficacy looked promising but needs confirmation in a randomized trial.

"Enormous Impact"

She added: "This device would have an enormous impact on patients with heart failure with preserved ejection faction if these results are confirmed and will challenge us to identify patients earlier in the disease process."

Kaye explained that left ventricular ejection fraction is preserved or near normal in at least half of all patients presenting with symptoms of heart failure, and a key pathological feature of this condition is elevated left atrial pressure particularly during physical activity, which is strongly related to symptoms and reduced survival.

Following the failure of several drug treatments for such patients, a transcatheter transvenous interatrial shunt device (IASD, Corvia Medical) has been developed with the aim of reducing the elevated left atrial pressure, while avoiding excessive left-to-right shunting.

The 8-mm shunt device has been shown to be linked to improved functional and exercise capacity, with reduced pulmonary capillary wedge pressure at 6 months after implantation in the REDUCE LAP HF study, although there were modest increases in right heart cardiac output and right atrial pressure.

The current report looks at longer-term effects of the device, focusing on clinical and echocardiographic outcomes after 1 year.

For this open-label study, 64 patients with left ventricular ejection fraction ≥40%, NYHA class 2–4, and elevated pulmonary capillary wedge pressure underwent implantation of the shunt device.

After 1 year, there were sustained improvements in NYHA class (P<0.001) and quality of life (Minnesota Living with Heart Failure score, P<0.001). Six-minute-walk distance improved from 331 m at baseline to 363 m at 1 year (P=0.001).

Echocardiography showed a small, stable reduction in left ventricular end diastolic volume index (P<0.001), with a concomitant small stable increase in right ventricular end diastolic volume index (P<0.001).

Kaye said: "These data suggest that there was no evidence of adverse remodeling following device placement, in keeping with the small size of the shunt."

Invasive hemodynamic studies performed in a subset of patients demonstrated a sustained reduction in the workload-corrected exercise pulmonary capillary wedge pressure (P<0.01).

"This means patients can do more physical activity for a given level of left atrial pressure," Kaye stated.

Survival at 1 year was 95%, and there was no evidence of device-related complications.

A randomized trial with a sham control is under way and should be completed next year.

In her discussion of the study, Sweitzer, who is an investigator in the ongoing randomized trial, congratulated Kaye and his team for beginning exploration of this novel therapy.

"This is important, as heart failure with preserved ejection fraction is very common, patients have quite poor quality of life as symptoms occur on exertion, and there is no pharmacological therapy for the condition."

Safety Reassuring

She said the most important result of this study was safety, as there are concerns about increased right-sided output due to the shunt. She said it was reassuring to see that flow remained left to right in all of the 75% of patients who were evaluated and that the mortality rate (4.6%) was low in comparison with other studies in this population.

On efficacy of the device, she stated: "Based on the limited follow-up data presented, there doesn't seem to be a marked changed in echo, exercise, or hemodynamic parameters between 6 and 12 months, and the suggestion of benefit seen at 6 months is maintained."

Sweitzer pointed out some limitations, including the nonrandomized open-label design, "giving potential for a placebo effect," hemodynamics having been conducted in only a small subset of patients, and lack of data on hospitalization for heart failure.

She said the magnitude of the improvement seen in the trial was similar to that that seen with cardiac resynchronization therapy and suggests that this could be a real effect.

She also pointed out that the study included a specific phenotype of patients with heart failure with preserved ejection fraction—those with predominant abnormalities of exercise hemodynamics and absence of pulmonary hypertension or renal failure.

"So a thorough baseline assessment of exercise hemodynamics would be important before implanting this device, which can be complex and will require collaborative efforts between heart failure and interventionist cardiologists to ensure that the appropriate patients are selected," she concluded.

The study was funded by Corvia Medical. Kaye is an unpaid member of the Corvia Medical Scientific Advisory Group.

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