Mesh cardiac-support device promotes long-term reverse-remodeling

December 20, 2007

Ft Lauderdale, FL - The CorCap (Acorn Cardiovascular), a polyester jacket for the heart that can resist or reverse the remodeling process in patients with dilated cardiomyopathy and heart failure, has demonstrated that the improvements it makes in cardiac size and shape are sustained for at least several years [1]. Compared with similar patients who didn't get the device, those who did showed persisting gains in cardiac structural parameters, such as sphericity index and LV end-diastolic volume (LVEDV), in a 36-month follow-up analysis from the shorter-term randomized trial previously but unsuccessfully submitted to the FDA for market approval [2].

"Implantation of the CorCap cardiac support device is safe in patients with heart failure and leads to beneficial cardiac remodeling that is characterized by reduced LV volume and a more elliptical LV shape," write the authors of the long-term analysis, led by Dr Randall C Starling (Cleveland Clinic, OH). Its reverse-remodeling effects, they observe, were in addition to those achieved by mitral-valve reconstruction performed at the same time as the implantation surgery. In addition, "there were no safety concerns with the device at three years and no clinically significant device-related complications."

Dr Douglas L Mann (Baylor College of Medicine, Houston, TX) led the authors of the short-term analysis. Both reports appeared in the October 2007 issue of the Annals of Thoracic Surgery.

The 36-month echocardiographic results represent a milestone of sorts for a line of research pursued by several companies developing cardiac-restraint devices. Although they are at different stages of development, the CorCap data seem to suggest all may be on the right track.

Definitely, the patient that's inotrope-dependent and knocking on the door for an LVAD is not a CorCap patient.

"We feel that [the CorCap study] has provided human data showing proof of principle, long term at 36 months, that this therapy results in beneficial, advantageous remodeling of big hearts," Starling said to heart wire . "Does it translate into clinical improvement? No, we can't make that statement." But there's a good amount of data tying reverse remodeling in dilated cardiomyopathy and heart failure to improved survival, he said.

Starling said the ideal patient for this form of therapy is probably one who remains symptomatic despite optimal medical therapy and, if appropriate, cardiac resynchronization therapy (CRT). "That is the kind of patient who I think would benefit from this type of therapy, whether it's CorCap only or one of the other products that's undergoing development right now." In general, he said, he'd characterize such a patient as NYHA class 3 "but hovering on class 4." But, "definitely, the patient that's inotrope dependent and knocking on the door for a [left-ventricular-assist device] is not a CorCap patient, in my mind."

The CorCap trial

In the study, 300 patients on optimal medical therapy for heart failure were randomized to be implanted with the device or not; they were stratified according to whether they also required and underwent mitral-valve repair at the same surgical session.

The odds ratio for the primary end point significantly favored CorCap therapy at 1.73 (95% CI 1.07-2.79, p=0.024) over the median 23-month follow-up. There were also significant device-related improvements in LVEDV (p=0.009), LV end-systolic volume (LVESV, p=0.017), sphericity index (p=0.026), and quality-of-life scores (p<0.04).

Significant differences between the groups in LVEDV, LVESV, and LV sphericity index persisted at the 36-month follow-up; clinical and functional outcomes weren't tracked for the long-term analysis. The sphericity index gains, write Starling et al, are "consistent with the left ventricle returning to a more elliptical shape."

I think this class of therapy is not going to go away.

Patients who received medical therapy only—that is, no CorCap and no mitral-valve repair—showed no changes in LVEDV until late in the follow-up, when it had increased due to continued remodeling. But LVESV fell progressively among those who received the CorCap without mitral-valve repair, the group observes. The average difference between the two groups reached 24.7 mL over the three years (p=0.042).

Control patients who had the mitral-valve surgery showed progressive reductions in LVEDV, but the improvements were more pronounced among patients who received both the valve surgery and the CorCap; the device's additive benefit averaged 16 mL over the three years (p=0.032).

"A similar pattern of change was observed for LVESV," the group writes. "The implications from this study are that a [CorCap] can provide beneficial remodeling when used independently and incremental benefit when used with concomitant therapies."

Work continues

Twice the CorCap study has gone before FDA advisory committees in attempts to earn a recommendation that the device should be approved, and twice a majority of committee members refused. As reported by heart wire on both occasions, majority panelists cited safety issues and reservations about the study's unusual and largely subjective composite primary end point (mortality, need for major cardiac procedures for worsening heart failure, or change in NYHA class), uncertainties over missing data, and other concerns.

Starling said that Acorn Cardiovascular is trying to address those concerns in further studies. "I think this class of therapy is not going to go away." He pointed out another device in trials that seems to work according to the same principles, the HeartNet (Paracor Medical). That device, as reported by heart wire earlier this year, is a nitinol mesh band that is placed around the heart using "minimally invasive" transthoracic surgical techniques.

"The way I see this field going is deploying these devices without a sternotomy, eventually perhaps even by cardiologists in the cath lab," Starling said. "But I think there's plenty of evidence now to show that these types of devices can provide a therapeutic benefit."

Both reports state that all coauthors have a "financial relationship" with Acorn Cardiovascular.


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