Hope for the Heart: Advances in Treatment
Today two-thirds of people survive their heart attacks, thanks to medical advances. Learn how some of these medical marvels evolved.
Clot Busters to Prevent Heart Attacks continued...
But challenging entrenched ideas by constant scientific inquiry is an essential driving force behind every medical marvel. "Once you actually start looking at stuff, it changes your understanding; your insights change, and what you can do changes," James says.
In 1980, DeWood published data showing that in virtually every heart attack observed by angiography, there was a clot blocking an artery.
"This was a revolutionary change in cardiology," says Jon Resar, MD, director of the Adult Cardiac Catheterization Laboratory at Johns Hopkins University School of Medicine in Baltimore, Md.
At that point, doctors realized that clot-busting medicines, which had been around in various forms since the 1930s, might save lives when given immediately after a heart attack. Now it was known that during a heart attack, a clot starves part of the heart of oxygenated blood, causing the muscle to die. The longer it lasts, the more damage is done. If the clot can be broken up quickly, less heart tissue dies, and you have better odds of survival.
Clinical trials on clot-busting drugs followed, which sought to find out if survival improved when they were used in treating heart attacks. "The improvement was quite pronounced," Resar says.
The best clot buster available in the early 1980s was streptokinase, a drug made from a bacterial culture. But drug companies soon got to work on making "designer" clot busters. In 1987, the FDA approved the first of the next-generation drugs, called tissue plasminogen activator (tPA), for dissolving coronary clots after heart attacks. In 1996, the FDA approved tPA for treating stroke.
Although tPA is no doubt a lifesaver, current medical opinion holds that the best treatment for a heart attack is angioplasty, a procedure in which a catheter with an inflatable segment is pushed through to the blocked artery, and inflated to break up the clot.
Andreas Gruentzig, MD, of Zurich, Switzerland, performed the first angioplasty in 1977, on a patient with stenosis, a condition in which an artery is narrow and hardened. After DeWood's findings, doctors quickly picked up angioplasty as a tool for intervening in heart attacks.
In addition to angioplasty, doctors now insert a mesh tube, called a stent that holds the artery open. Very recently, stents have been coated with a polymer that releases a drug to prevent scar tissue from forming in the artery and causing it to clog, which had been a major problem with them.
Today, many hospitals are equipped with "cath labs" where a specialized team can immediately do angioplasty and put in a stent when a heart attack victim arrives. ERs and clinics without these facilities use clot-busting drugs.
A Lifesaving Shock to the Heart
As technology generally gets more sophisticated, so, too, does medical treatment. The story of the implantable cardiac defibrillator (ICD) really begins with experiments in electricity at the turn of the last century. By the early 1970s, electrical engineering was an advanced science, and doctors had begun to tap the potential of electrical devices for treating heart disease.