Medical Device Daily Contributing Writer

The new GeoForm annuloplasty ring for repair of the mitral valve from Edwards Lifesciences’ was the focus of a round table discussion presented as a live webcast. Steven Bolling, MD, of the University of Michigan Cardiovascular Center (Ann Arbor, Michigan), an internationally known cardiac surgeon and co-inventor of the GeoForm ring, led the panel and showed film of a mitral valve repair operation using the new annuloplasty ring to repair the patient’s leaking mitral valve.

In addition to correcting the valve regurgitation, the heart valve annuloplasty ring also helps congestive heart failure CHF) patients regain lost heart function. The annuloplasty reverses the disease’s effects on heart geometry and eases disabling symptoms.

The GeoForm ring has been approved by the FDA for use in repairing regurgitant mitral valves. New data indicates that it also reshapes the left ventricle, which often becomes distended and misshapen after a heart attack or infection of the heart muscle.

Nearly five million Americans have CHF, and the number is expected to climb.

“Congestive heart failure is a ventricular disease, but previous efforts to reshape the ventricle by repairing the mitral valve have been hit-or-miss,” said Bolling, who heads the University of Michigan’s (U-M) Mitral Valve Clinic and is a professor of surgery at the U-M Medical School. “This ring’s special three-dimensional shape makes it easier for the surgeon to pull the heart muscle up in a way that forces the left ventricle to remodel — whether it wants to or not — and returns the heart to a pointy, or ellipsoid, shape from a rounded shape.”

He likened the effect to turning the normally football-shaped heart that has become basketball-shaped back to normal configuration.

According to the American Heart Association, about one in five people now over 40 years of age may develop heart failure in their lifetime. Many CHF patients develop cardiomyopathy, a weakening of the heart muscle that distorts and enlarges the left ventricle, inhibiting the mitral valve’s flap-like leaflets from properly closing and causing blood to flow backward through the heart.

Failure to adequately reverse the onset of this condition, known as mitral valve regurgitation, can further lead to even greater mitral valve regurgitation and an increased likelihood of heart failure, according to a 1998 study published by Bolling and his colleagues in the Journal of Thoracic and Cardiovascular Surgery.

The introduction of Edwards’ new GeoForm mitral valve repair ring comes on the heels of a recent study published in the New England Journal of Medicine, which found that people who had severely leaky mitral heart valves but no symptoms were five times more likely to die of a heart problem, and six times more likely to have heart failure or some other serious cardiac problem.

Lead researcher Maurice Enriquez-Sarano, MD, professor of medicine at the Mayo Clinic and director of the Mayo Clinic’s valvular heart disease clinic, estimates that of the approximately 2.7 million Americans who have notable mitral valve leakage, about 600,000 are probable candidates for early intervention.

Bolling opened the discussion by defining the session as “looking at a valvular solution to a ventricular problem in the heart. My co-moderator is Wei Lau, MD, director of Cardiac Anesthesiology. We’re going to talk today about congestive heart failure. We’ve studied 1,500 patients and seen moderate to severe mitral regurgitation at first visit to the doctor in 40%.

The regurgitation is caused by progressive left ventricular dilation. Over time the papillary muscles in the ventricle are moved apart and angulated, pulling leaflets of the valve down and outward. This also occurs with coronary artery disease where parts of the heart are damaged.”

Bolling estimated about 600,000 people with heart failure in the U.S. with 250,000 to 300,000 new onset cases of severe mitral regurgitation every year. About half those patients can have medical therapy, so about 150,000 new cases are eligible for surgery. Last year only 45,000 of these procedures were done so there’s three times the cachement of mitral valve cases.”

A member of the Internet audience asked how it was decided that a patient was appropriate for the procedure.

Lau answered, “We look at how well they will do if we don’t operate. Ejection fraction is not a good measure. Regurgitation is the biggest predictor of mortality. Not just severe, but even moderate grades hurt long-term outcomes.”

Lau added: “We now know that mitral regurgitation can be either anatomic or geometric. Anatomic regurgitation comes from rheumatic or degenerative disease, endocarditis or is congenital. Geometric regurgitation is caused by cardiomyopathy or ischemic heart disease.”

Referrig to the film of the annuloplasty procedure,” Bolling said, “We see here a transesophageal echocardiograph clearly demonstrating the unusual movements of the mitral valve leaflets. You can also see that the entire ventricle gives the heart an appearance more like a basketball than a football — its normal shape. We are performing a right thoracotomy with beating heart” — meaning no use of a heart-lung machine. “We’ve performed 193 of these cases with a 1% to 5% 30-day mortality rate.

“We’ve also learned it’s better to use smaller rings. We don’t use partial or flexible rings. Recurrence of regurgitation with flexible is 5X that of rigid. Ours are all rigid and complete. And, we use the smallest ring we can.”

A questioner asked about potential use in cases of atrial fibrillation.

“That’s a chicken and egg issue,” Bolling said. “Often the fibrillation is caused by the ventricle’s reshaping. That produces high wall stress which encourages fibrillation. We find these annuloplasty procedures reshape the heart and thereby reduce instances of fibrillation. Those patients get relief.”

Again referring to the film, he noted the opening into the right atrium. “Then we use a straight transeptal entry into the left atrium. I do this approach when I know that we are going to replace the tricuspid valve. Opening up towards the superior vena cava and then we see the mitral valve. The mitral valve itself is normal, not stenosed. Here you can see the anterior annulus.”

A GeoForm ring reduces the anterior posterior diameter of the mitral valve by about 40%. This prevents the valve from opening back up.

Bolling continued: “Here we are using a size 26 GeoForm. You can see the ring has an odd 3-D shape [that] gives less stress and strain on the tissue. This 3-D echo demonstrates the GeoForm prevents early posterior loitering of the leaflets as they are opposed early in systole.”

The film then showed Bolling beginning to sew the GeoForm in place.

“We use a lot of stitches with the GeoForm because it is a rigid ring and we want to prevent dehiscence. We want the annulus to be this 3-D dog-bone shape which then causes the ventricle to have the same shape. We use a very small needle and lots of stitches, averaging 18.8 stitches to secure the ring.”

Then Lau explained: “We use straight forward mattress stitches with no pledgets. This is a very simple technique. We simply stop the heart, put in a lot of stitches and put them down. Any competent surgeon can do this.

“The ring is made of titanium and covered with Gore-Tex. We start at the outside of the ring and tie toward the hump. The first stitch will get most push.”

The final shot of the video showed the intraoperative, post-implant echocardiogram. The valve showed no regurgitation, and the ventricle appeared restored and remodeled.

Lau said in closing, “This is the first time a device has acutely changed the left ventricle. We see immediate improvement in the zone of coaptation. Our long-term results are 2.5 years out. We’ve seen zero mortality post operatively and no mitral stenosis with this technique.”