Hypothermia helps heart attack patientsby Lorna Benson, Minnesota Public Radio
Hypothermia is something to avoid, usually. But research has shown that inducing a mild state of hypothermia following a severe heart attack may help patients avoid brain damage and increase their survival odds. Researchers have known this for some time, but they haven't had the technology to induce hypothermia safely in real world emergencies until recently.
Now, with the aid of a cooling machine, some Minnesota hospitals have started using the hypothermia technique and are reporting promising results.
Minneapolis, Minn. — Brian Kuczmarski doesn't look like he barely survived a massive heart attack. Just one week after leaving the hospital, he easily walks his daughter Emma two blocks to the school bus stop.
"Here you go, kiddo. Have a good one!"
But there are some lingering signs of Kuczmarski's ordeal. His speech pattern isn't quite as fluid as it was before the heart attack. During an interview with his wife, Linda, back at his house, it's clear that his memory isn't fully restored either.
"I'm 42 years old. No. Oh," he laughs. "I'm neurologically unsound yet. I'm 46. I'm sorry."
These sorts of memory problems are common among heart attack survivors who have suffered a loss of oxygen to their brains.
Kuczmarski is lucky. His memory loss is minimal, despite having a blockage in his heart that was so large it completely shut off the blood flow to the rest of his body.
"I know from looking at the records that I went into full cardiac arrest five times on the way downtown to Abbott. One time they actually stopped the ambulance to paddle me," he says.
Cardiologist Dr. Michael Mooney was on call when Kuczmarski finally arrived at Abbott Northwestern Hospital after a 20-minute ambulance ride.
Mooney immediately threaded a stent through an artery in his patient's groin leading to the blocked heart valve. But even with his heart function restored, Mooney knew that Kuczmarski was still in grave danger from the after-effects of his heart attack.
"It sets up a series of processes that happen for the next six hours that continue to cause damage. And so instituting the hypothermia helps to arrest those processes that continue to damage brain tissue," he says.
Mooney hooked up Kuczmarski to a cooling machine called the Arctic Sun. The device is equipped with water tubes attached to a vest that covers the patient's torso.
Within a few hours, Kuczmarski's body was 4 degress Celsius cooler, and he was in a mild state of hypothermia. Since he was in a coma, he has no memory of it. But his wife Linda recalls what it was like.
"He was very cold. We compared it to like in a meat locker kind of. That's how he felt," she says.
Inducing hypothermia is a delicate process. If doctors cool the body too much, a patient can develop additional heart problems and other organs can fail. That's been the main drawback to previous methods using ice to cool patients. But Mooney says the Arctic Sun technology has taken the guesswork out of the procedure.
"It's basically a fancy cooling blanket that auto-regulates the body temperature. It has both the capacity of cooling and warming in alternating fashions, to hit a precise target and to keep it there."
Mooney says his hospital hasn't used the Arctic Sun on enough patients yet to have a statistically meaningful analysis of its effectiveness. But of the 12 patients who have used it thus far, he says the results have been similar to the results reported in a New England Journal of Medicine study four years ago.
In that study, patients who did not receive cooling therapy after a massive heart attack had a 57 percent chance of dying or having significant brain damage. Mooney says among the patients who did receive the hypothermia therapy, that rate of death or brain injury dropped to 38 percent.
"We ordinarily, in cardiovascular outcomes, look for 2 to 3 raw percent improvement. This one has 17 to 20 percent raw improvement, and that's a huge clinical impact. And that's part of the reason we have been so active in developing this," he says.
Dr. Mooney has helped develop clinical protocols to determine which heart attack patients are the best candidates for hypothermia therapy.
For recovering heart attack patient Brian Kuczmarski, there are several possible reasons why he's doing so well today.
He thinks his family's decision to call 911 rather than drive him to the hospital helped. He says paramedics arrived at his home quickly, and they were able to revive him several times during his ambulance trip to the hospital. He also believes the medical team did a great job once he got to the hospital.
And he suspects the 24 hours he spent in a mild state of hypothermia helped too.
"It's really hard for me to know one way or the other, except that, you know, the proof is in the pudding. I'm alive. I'm well. I came through it all. I've gotta believe that it was helpful," he says.
Other Minnesota hospitals are also using hypothermia therapy to treat heart attack patients, including Hennepin County Medical Center, Mercy and Unity Hospitals in the northwest metro area, and St. Cloud Hospital.
- Morning Edition, 05/30/2006, 7:20 a.m.