Heart attack patients are half as likely to suffer cardiac arrest or death if paramedics give them an IV solution of glucose, insulin and potassium during transport to the hospital, according to a large study performed in New Mexico and other sites. Patients who received the inexpensive solution also experienced less damage to the heart than those who received a placebo, according to a study published March 28 in the Journal of the American Medical Association.
If the treatment is approved for routine practice, it could offer paramedics a new tool for minimizing the worst consequences of a heart attack, medical officials said.
"The thing we're trying to do is save heart muscle tissue," said Kurt Krumperman, executive director of Albuquerque Ambulance Service, which participated in the three-year study.
The glucose-insulin-potassium solution "has the potential to prevent heart muscle damage at the cellular level," he said. "It offers the promise of preventing the damage from being as bad." Each year, about 785,000 Americans have a first heart attack and an additional 470,000 have a second or subsequent heart attack, according to the Centers for Disease Control and Prevention. Heart disease is the nation's leading cause of death, resulting in one in four U.S. deaths.
A heart attack is caused by a blocked artery that deprives the heart of blood and oxygen.
The glucose-insulin solution minimizes muscle damage by providing the heart with a usable source of energy until physicians can treat the cause of the heart attack, said Dr. Michael Richards, chairman of University of New Mexico Hospital's department of emergency medicine and a co-author of the study.
Insulin helps the heart absorb the glucose and potassium is an electrolyte crucial to muscle function.
"It's designed to buy a little more time," Richards said. The solution "decreases the risk of having a bad outcome."
The solution itself costs about $50 per patient, the study estimated. The solution does not require U.S. Food and Drug Administration approval, Richards said, but medical professionals are unlikely to adopt it as a standard practice before a larger study is performed, he said.
The study was based on the outcomes of 871 patients recruited by paramedics with 36 emergency medical systems in the U.S. from 2008 to 2011. Emergency personnel in Bernalillo and Sandoval counties recruited 187 patients for the study, Richards said. Nearly half the patients received an intravenous solution that contained 30 percent glucose. The other patients received a placebo.
The worst outcome of a heart attack is cardiac arrest, in which the heart stops beating, often resulting in death. Of the 871 patients enrolled in the study, 58 experienced cardiac arrest or death, according to the study.
Among patients who received the glucose-insulinpotassium solution, 4.4 percent experienced cardiac arrest or death - a rate about half that of patients who received the placebo, the study reported.
A 30-day follow-up exam found that patients who received the glucose-insulinpotassium solution had significantly less damage to the left ventricle - the crucial chamber of the heart that pumps blood to the body.
The solution was not able to entirely prevent permanent damage to the heart, or myocardial infarction, Richards said.
"But if you were actually having an infarction, the (glucose-insulin-potassium solution) decreased the size of the heart attack, and it decreased your risk of dying or having a cardiac arrest," he said. A pump similar to this one was used by paramedics to deliver an intravenous solution of glucose, insulin and potassium to heart attack patients en route to the hospital.