Cardiologists at Rush-Presbyterian-St. Luke's Medical Center in Chicago are testing a new therapy that cools down the body of heart attack patients to reduce the amount of tissue damage that occurs during a heart attack.
Rush is the only Midwest medical center participating in a nationwide study to determine the safety and effectiveness of hypothermia administered to patients who are having a heart attack. Patients who are admitted to the Rush emergency room within six hours of experiencing chest pain and have EKG changes confirming a heart attack will be asked to participate in a research study to test the use of an intravascular device that cools the core body temperature from 98 degrees to 89 degrees. Because the body is cooled "from inside out," the skin remains warm while the heart and other internal organs are cooled. This approach "fools the body" and is surprisingly effective at preventing patient discomfort. In fact, some patient not that they feel "too warm" during this therapy.
Heart attacks often occur when blood vessels are blocked, prohibiting oxygen and nutrient rich blood from reaching tissue behind the blockage. If this tissue is deprived of blood (ischemia), it can quickly die. This tissue death, known as necrosis or infarction, is irreversible.
"Tests on animals have shown that circulating a cool saline solution within a long balloon catheter placed in the inferior vena cava, can reduce body temperature and diminish the amount of heart tissue damage by as much as 90 percent," said Dr. Gary Schaer, director of the Cardiac Catheterization Laboratories at Rush. If doctors can prevent damage during the early stages of a heart attack, patients will have a much better chance at future recovery.
Schaer and co-investigators, Dr. Jeffrey Snell, associate director of interventional cardiology, and Robert Hendel, director of the Rush coronary care unit, are among a small group of cardiologists around the country testing the Radiant Medical SetPoint Endovascular Temperature Management System. The system involves the use of a disposable, single-use catheter that is inserted in the femoral artery near the groin. Patients will receive a mild sedative and a blanket to keep warm during the procedure. The device circulates cool saline solution throughout the balloon catheter, thereby maintaining the body temperature of 89 degrees the researchers believe is necessary to prevent further tissue damage after a heart attack. It takes approximately 30 minutes for the patient's body temperature to reach the target of 89 degrees, Snell said. The cool saline solution never comes in contact with the patient's own blood or fluids, he said.
After the 90-minute procedure, the patient remains at that temperature for another three hours before being warmed up gradually with the SetPoint device.. Patients will receive medications to counter the body's natural inclination to warm itself by shivering, which is the rapid and uncoordinated contraction of skeletal muscles. The patients will be given an angiogram at a 30-day follow up visit to determine the extent of their tissue damage near the heart.
"The purpose of this clinical trial is to determine the true impact that this new method may have for heart attack patients. Hopefully, we can reproduce the positive results demonstrated in preliminary trials," Dr. Hendel said.
Coronary heart disease is the single leading cause of death in the United States, accounting for one of every five deaths in this country.
Rush-Presbyterian-St. Luke's Medical Center includes the 824-bed Presbyterian-St. Luke's Hospital; 110-bed Johnston R. Bowman Health Center for the Elderly; Rush University (Rush Medical College, College of Nursing, College of Health Sciences and Graduate College); and seven Rush Institutes providing diagnosis, treatment and research into leading health problems. The medical center is the tertiary hub of the Rush System for Health, a comprehensive healthcare system capable of serving about two million people through its outpatient facilities and five member hospitals.