Heart failure

Interatrial shunt could be a new strategy for managing HFPEF


Patients diagnosed with heart failure have seen dramatic improvements in their exercise capacity and symptoms after receiving a novel inter-atrial septal shunt implant.

The transcatheter interatrial shunt device (IASD) is the first device designed to address the cause of heart failure symptoms in patients who have heart failure with preserved ejection fraction (HFPEF).

Presenting the 12-month follow up data of the REDUCE LAP HF trial at the 2016 American Heart Association’s Scientific Sessions earlier this week, Professor David Kaye from the Baker IDI in Melbourne said the device appears to safe and could be a new strategy for managing HFPEF – a condition that, until now, has had no successful drug or device intervention to improve mortality or hospitalisation risk for patients diagnosed with the condition.

Professor Kaye said about 50% of patients presenting with heart failure (HF) have either a preserved or near normal ejection fraction and one of the physiological features of this form of HF is an elevated left atrial pressure, which is particularly noticeable during exercise.

According to Professor Kaye there is a strong relationship between symptom severity and left atrial and pulmonary capillary wedge pressure.

“Survival is often worse in HFPEF patients with elevated filling pressures, particularly during exertion – so the concept is that a reduction in left atrial pressure would reduce pulmonary congestion and improve symptoms for the patient,” Professor Kaye said at a press conference.

The device was implanted in 64 patients with an LVEF rate of 40% or more in an open label trial.

“The majority of patients were quite symptomatic with NYHA class III symptoms,” Dr Kaye noted.

One year after transcatheter shunt placement, patients had maintained the improvements seen at six months, demonstrating the clinical efficacy of the device.

Patients moved to New York Heart Association class I or II, quality of life scores were bolstered by 15 points on the Minnesota Living with Heart Failure questionnaire on average (P<0.001) and most patients gained 33 meters in the 6 minute walk test (P<0.01).

One of the concerns with a left to right shunt was the possibility of right ventricular remodeling over time, noted Professor Kaye.

However at one year, echocardiographic data showed no change in left ventricular (LV) ejection fraction or atrial volumes from baseline but there was an increase in right ventricular (RV) ejection fraction; a reduction in LV end-diastolic volume index; and an uptick in RV end-diastolic volume index.

Meanwhile there was an increase in exercise capacity – both in terms of duration and workload – measured by haemodynamic studies but more importantly there was an improvement in the work index wedge pressure said Professor Kaye, which meant that patients could do more physical activity for a given level of left atrial pressure.

There were three deaths and one stroke in a patient who had a higher CHADSVASC score but there were no episodes of other systolic embolic events and no device related complications requiring removal of the shunt, Professor Kaye added.

Commenting on the study Dr Nancy Sweitzer from the University of Arizona in the US said the safety aspect of the trial at 12 months was reassuring because there had been concerns about the long-term effects of chronic elevation in right-sided outputs due to creation of a shunt.

“In comparison to other HFpEF patient trials I do think the magnitude of improvement seen in patients in the REDUCE LAP trial is provocative and suggests that perhaps this is a real effect and not just a placebo effect,” she said referring to the fact that the trial was a non randomised open label design – which could leave the trial open to bias.

Currently there is a randomised study with a sham control intervention underway. Results from this study are expected early next year.

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