Investigators study new drug therapy to halt heart attacks
Dr. William Hillegass and Nurse Cathy Longeway are testing a drug combination to halt heart attacks. (Photo by Donna Jones Bailey)
Vanderbilt University Medical Center is among a group of leading heart centers testing a drug combination that may be the best medical therapy yet for stopping a heart attack in progress.
The combination of two powerful blood thinners, abciximab, and reteplase (rPA), will be given to patients in the VUMC Emergency Department who are having heart attacks to determine if the drugs can restore blood flow even before angioplasty can be done.
"A variety of studies have been done that suggest that this combination of drugs is more effective and safer than rPA alone or any other known thrombolytic drug for treating acute myocardial infarction," said Dr. William B. Hillegass Jr., assistant professor of Medicine.
The goal in treating a heart attack is to restore blood flow as soon as possible during the first few hours of the attack before severe permanent muscle damage is done.
At VUMC, the standard approach for patients diagnosed as having a heart attack is to take them to the cardiac catheterization lab. There, they receive abciximab alone and undergo what is called primary angioplasty, which uses balloons, catheters or stents to open the blocked coronary artery while the heart attack is in progress.
The average time from diagnosis of a heart attack to arrival in the cath lab for primary angioplasty is 30-60 minutes at VUMC, Hillegass said. That compares to an average of 60-90 minutes at most hospitals that do primary angioplasty.
The new trial is a collaborative effort of physicians from the Cardiology Division and the Department of Emergency Medicine.
Vanderbilt cardiologists and emergency medicine specialists are the only physicians in Middle Tennessee participating in the randomized, Phase II trial (nicknamed the SPEED Trial for Strategies for Patency Enhancement in the Emergency Department). The SPEED trial is being conducted at 37 centers, 32 of them in the United States and five in Europe.
Patients will receive the abciximab-rPA combination and then proceed to the cath lab as they would otherwise.
Once there, they will be examined to determine whether the drugs have restored blood flow. If not, they will then undergo angioplasty to open the blocked artery.
"In this trial, we'll be using that window of time between presentation with an MI and arrival in the cath lab to give the medicine a chance to provide coronary reperfusion even before we can do the interventional procedure," Hillegass said.
Preliminary studies indicate that the abciximab-rPA combination can restore blood flow in 80 percent of patients, compared to about 60 percent success in patients who undergo the currently used thrombolytic therapy, accelerated delivery of the drug known as tPA, he said.
These studies also found that the risk of bleeding with the combination therapy was comparable to or less than that of standard thrombolytic therapy, he said.
If the abciximab-rPA combination proves as effective as these early studies indicate, it will be very beneficial in smaller, rural hospitals without the ability to do primary angioplasty, said study coordinator Cathy L. Longeway, R.N., M.S.N.
"It may offer people in areas where the hospitals do not offer primary angioplasty a chance at the same outcome," she said.
In addition, the new drug combination may prove even better than primary angioplasty, Hillegass said.
"The data looks so good for this regimen, I'm pretty certain this is going to become standard of care," he said.