Monday, April 21, 2008 Dumaguing: Drugs show promise in heart treatment trial By Dr. Victor Dumaguing To Your Health
HUMAN atrial natriuretic peptide (hANP), a drug used in Japan to treat acute heart failure, reduced heart muscle damage by nearly 14.7 percent and cut readmissions for heart failure by 83.6 percent in heart attack patients undergoing balloon angioplasty to reopen clogged arteries, researchers reported at the American Heart Association's Scientific Sessions.
Researchers presented the results of the Japan-Working Groups of Acute Myocardial Infarction for the Reduction of Neurotic Damage by ANP or Nicorandil (J-WIND) in a late-breaking clinical trials session.
Researchers also said nicorandil, a nicotinamide nitrate that is a class of drugs called channel activators because they open the heart's adenosine triphosphate (ATP) sensitive potassium channels, was associated with a 38 percent reduction in cardiac deaths (deaths due to heart dysfunction).
However, infarct size or improvement in the overall survival rate didn't decrease. Potassium channels are pores that span the membrane of many kinds of cells.
They influence the activity of cells by selectively changing the balance of potassium inside and outside of the cell. ATP is produced in the cell and can activate these channels.
Nicorandil, which relaxes and dilates blood vessels, is used as a daily treatment for angina, which is a symptom of reduced blood flow to the heart.
"There are no reports of the reduction of infarct size (the area of irreversible heart muscle damage) by any drug in large scale trials using patients with acute heart attack," said Musafumi Kitakaze, M.D., Ph.D., director of the Cardiovascular Division of the National Cardiovascular Center in Suita, Japan.
"These results will change the strategy of the acute-phase treatment of heart attack."
J-WIND is a prospective, placebo-controlled trial in 1,216 patients at 65 medical centers in Japan that looked at two drugs- the hormone hANP, which is approved for use in Japan but not in the United States, and a potassium channel activator called nicorandil that is widely used as a daily treatment for angina (chest pain), a symptom of reduced blood flow to the heart.
Patients were randomly assigned to receive one of the two investigational drugs or a placebo. Those in the hANP group received the drug as an infusion for three days.
Those in the nicorandil group got an initial dosage of the drug, followed by a 24-hour infusion. Researchers analyzed 1,064 patients for infarct size.
They also analyzed 1,104 cases for the endpoints of cardiac deaths, cardiovascular events, and heart failure.
Percutaneous coronary intervention (PCI), the medical term for balloon angioplasty effectively reopens clogged arteries when doctors thread a tiny balloon-tipped catheter to the area of blockage and then inflate the balloon.
Heart attack patients who undergo PCI to reopen clogged arteries face double jeopardy: their hearts can be damaged by the heart attack and they can sustain more damage from the body's inflammatory response when the blood flow is restored. That back-end damage is called reperfusion injury.
"Our conclusion is that hANP is a hopeful adjunctive drug for reducing infarct size and subsequent re-hospitalization due to heart failure," said Kitakaze, who also is chair of the J-WIND trial.
"While the nicorandil did not reduce infarct size or improve overall survival rate, it holds the possibility of reducing cardiovascular mortality and therefore warrants further study."
