LV 'Augmentation' Implant for Dilated Cardiomyopathy: Promising (Very) Early Data

November 25, 2013

DALLAS, TX — Early and quite preliminary results of the AUGMENT-HF study look promising for a procedure that seems to alleviate LV wall stress, restore some of the heart's natural shape, and possibly improve functional capacity in patients with dilated cardiomyopathy.

Thirty-day and six-month outcomes in less than half of the evaluation's projected 76 patients, randomized to the new procedure or standard care, suggest the procedure may well partly restore functional capacity and quality of life in patients who remain in bad shape despite optimal medical and device therapy.

The procedure entails injection of an initially liquid alginate polymer material into the ventricular wall via a small anterior thoracotomy; the biopolymer firms up to create a kind of flexible scaffolding. The material  for implantation, Algisyl-LVR hydrogel (LoneStar Heart, Dallas, TX), is derived from seaweed, has no known antigenic effects, and has "a long-term safety track record" in other clinical applications, explained Dr Douglas L Mann (Washington University School of Medicine, St Louis, MO) to heartwire .

"In animal studies, the gel implant becomes encapsulated in a fibrous cap," he said, suggesting that it elicits a wound-healing response.

The results are "based on a prespecified interim analysis, so it's important to not overstate the findings," Mann said, stating what he cautiously reiterated several times when presenting the analysis last week here at the American Heart Association 2013 Scientific Sessions .

Circumspection seems appropriate in interpreting the procedure's performance; prior methods for restoring ventricular structural dynamics when the LV wall is too stretched to perform well have shown mixed results. Some showed early success but faltered later. Examples include ventricular-restraint devices such as the CorCap (Acorn Cardiovascular) and various surgical cardiomyoplasty techniques.

Thirty patients (out of a planned 76) with dilated cardiomyopathy, an LVEF <35%, and a peak VO2 of 9 to 14.5 mL/kg/min, most of whom were in NYHA class 3 and two-thirds of whom had ischemic heart disease, were randomized at 16 centers in Australia, Germany, Italy, the Netherlands, and Romania. About 43% overall had cardiac-resynchronization therapy (CRT) devices.

The mean procedure time for patients assigned to the intraventricular injections was 79 minutes; they spent an average of 5.4 days in the intensive-care unit and 17.4 days in the hospital.

No patients died within 30 days. Two Algisyl patients subsequently died; one from drug-resistant Klebsiella pneumonia 66 days after surgery, the other from "critical illness secondary to sepsis" at 49 days. One usual-care patient died; the cause was worsening HF, at day 39.

There were no signs on "careful Holter analysis" that the novel procedure promoted important arrhythmias; in fact, arrhythmias were fewer in the implanted group, according to Mann.

In the Algisyl group, mean six-minute-walk distance improved from 235 m at baseline to 328 m (p=0.008) at three months (23 evaluable patients) to 345 m at six months (p=0.03) vs baseline (10 evaluable patients). It didn't improve significantly at any time points in the control group.

NYHA class followed exactly the same pattern, with Algisyl patients improving significantly at both month 3 (p=0.002) and month 6 (p<0.001) vs baseline and neither in controls.

At three months, 40% of Algisyl patients showed improved peak VO2 by at least 1.0 mL/min/kg (30% unchanged and 30% worsened); that compared with only 8% of controls (42% worsened and 50% unchanged).

"I think these results are extremely encouraging with respect to safety and efficacy," but they are far from definitive, Mann said during the panel discussion after his presentation. He said there are plans to compare cardiac structural and functional echocardiographic end points between the two groups. And LoneStar Heart is developing techniques and hardware for replacing the anterior thoracotomy with a percutaneous approach.

The study is funded by LoneStar Heart, for whom Mann discloses being on a scientific advisory board.

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