Een artikel uit 2006.....
Shock waves can save hearts
Extracorporeal cardiac shock wave therapy sounds like something Capt. Picard might need after a run-in with the Borg. But it's actually a new, real-life way to treat end-stage heart disease.
A team of Japanese researchers found that blasting the heart with shock waves helps patients grow new blood vessels and increase blood flow.
Coronary artery disease -- a leading cause of death in men and women in the United States -- happens when plaque builds up in blood vessels, blocking the flow of oxygenated blood to the heart muscle. Medication, angioplasty or bypass surgery can sometimes treat the disease. But when these approaches aren't enough, the only hope is to grow new blood vessels. Gene and cell therapies can also engender new blood vessels, but those procedures require surgery, which is risky for elderly or severely sick patients.
"I felt that we needed to develop a noninvasive therapy for those patients," said Hiroaki Shimokawa, a cardiologist at Tohoku University Graduate School of Medicine in Sendai, Japan. He and his team turned to extracorporeal (outside the body) shock wave therapy.
Scientists had shown the technique could stimulate growth factors in human blood vessel cells in the laboratory, and after getting positive results in animal studies the team performed the first clinical trial of cardiac shock wave therapy in humans.
Shimokawa and his colleagues aimed low-energy pressure waves at the chests of nine patients with end-stage coronary artery disease. During a typical session they hit 20 to 40 different areas of the heart with 200 pulses each. Blood flow increased and symptoms were alleviated in all patients, suggesting the growth of new blood vessels.
The researchers used a shock wave generator made especially for the heart. Using its fine adjustments, they could focus waves on a 2-square-millimeter area, and aim them virtually anywhere.
"Since we can focus at any point in the heart muscle with our machine, the patients can just lie on the table. They don't need to move," Shimokawa said.
Besides increasing the safety and comfort of the patients, this level of control allowed the researchers to treat just the parts of the heart where blockage occurred. Follow-up tests showed increased blood flow only in those areas, lending further weight to the conclusion that shock waves are a viable treatment.
Pigs treated with shock wave therapy grew more blood vessels than a control group after four weeks.
Potential risks include arrhythmia and damage to the heart muscle, but no negative side effects were reported in this study, which was published earlier this year in the journal Coronary Artery Disease.
Now the researchers are conducting a larger, placebo-controlled clinical trial to confirm the findings. Shimokawa presented his team's work at the recent joint meeting of the Acoustical Society of America and the Acoustical Society of Japan in Hawaii.
"When he gave his talk, the whole room was entranced," said Robin Cleveland, a physicist in the Department of Aerospace and Mechanical Engineering at Boston University. "The results he's been able to get are really spectacular."
Cleveland has studied lithotripsy -- the use of shock waves to break up kidney stones -- for 10 years. He said the application of shock waves to treat heart disease is an exciting step for the field.
Extracorporeal shock waves are also used to treat tendonitis, ease foot pain and even heal broken bones.
"But the catch is we still don't understand how they work," Cleveland said. One hypothesis is that they kick-start repair mechanisms by causing slight tissue damage. "Maybe the shock waves add just enough extra damage to suddenly tell the body there's a problem that needs fixing, like a little Post-It note," he said.
Scientists do know that while shock waves can benefit some organs, they can damage others, like the lungs -- a poorly aimed shock wave could cause hemorrhaging. Shimokawa's team uses detailed 3-D images of each patient's heart to figure out where to focus the waves.
"That's why the operator should be a cardiologist," Shimokawa said.
The preliminary results of the second clinical trial are promising, and if the rest of the study goes well, Shimokawa will apply to have the procedure approved by the Japanese government within a year. "And in several years I think our shock wave therapy will be distributed throughout the world," he said.