Shocking Treatment for Heart Repair

A device sends shockwaves to prompt blood vessel growth.

Cardiac patients are living longer and longer--up to 20 years after receiving stents, a heart bypass, or heart-valve replacements. But extended lifespan is often accompanied by other complications, as a repaired heart can still have difficulty getting enough oxygen. The accompanying pain, a squeezing pressure in the chest called angina, can plague patients for years, and there are some for whom no surgery can provide relief. But a noninvasive shockwave machine could help prompt the growth of new blood vessels, restoring the heart's oxygen supply and alleviating the pain.

Shock treatment: These images show blood flow in the left ventricle of a 62-year-old patient’s heart (red indicates blood flow). The images on the left show the ventricle before acoustic shockwave treatment; the ones on the right show it after treatment. Credit: R. Erbel, Essen University, Germany

In a clinical trial at three centers across the United States, cardiologists are testing the safety of the shockwave device, developed by Maryland-based Medispec. The "Cardiospec" machine is based on the same sound-wave technology used to break up kidney stones, but it requires only about one-tenth the energy. "Shock waves are acoustic waves that create pressure that can be focused," says Medispec's Gil Hakim, the company's director of new product development. Direct that pressure toward the heart muscle with just the right intensity, and it causes the body to produce new blood vessels.

Researchers aren't sure precisely why shockwaves have this effect--they believe that the pressure may induce a cascade of events that mimic wound-healing, recruiting undifferentiated cells to the area to build blood vessels. Preliminary studies show that about 70 percent of the patients who undergo the shockwave procedure experience somewhere between a 60 to 70 percent improvement in blood flow to their hearts.

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"Patients with [recurring] angina consume a lot of medical care because they have multiple emergency visits, they have multiple angiograms, and their quality of life is extremely low," says Amir Lerman, a cardiovascular specialist at the Mayo Clinic in Rochester, MN, who's heading up the Cardiospec trial. And, he notes, the treatments available to these patients to date are short-term therapies that address the symptoms rather than the cause. "These patients currently don't have any alternative solution. And we need to find one because they live a long time."

The trial will recruit 15 patients--five each at the Mayo Clinic, the University of California at San Diego, and Albert Einstein Medical Center in Philadelphia--and it will consist of nine treatments applied over a nine-week period (three treatments per week during weeks one, five, and nine).