Experts split over best AMI therapy: Thrombolysis or PTC angioplasty?
Speed of treatment more important than type
Although both are effective in restoring coronary artery flow in most acute myocardial infarction (AMI) patients, proponents of thrombolysis say it is best because it can be given more quickly than percutaneous transluminal coronary angioplasty (PTCA). Advocates of PTCA claim that long-term patency rates are higher than with thrombolysis.
Regardless of the treatment, what is not debated is that the therapy needs to be administered quickly, faster than most hospitals are capable of doing it. A newly published debate over whether hospitals should be favoring thrombolysis over PTCA for AMI patients is adding impetus to reducing door-to-treatment time for patients entering the emergency department (ED). In a commentary in a recent issue of the New England Journal of Medicine, cardiologists make equally compelling arguments for both thrombolysis and PTCA for routinely treating AMI.1
Experts familiar with the debate say it isn’t feasible for many hospitals to offer PTCA in a timely manner. To shorten the delivery and avoid complications with either procedure, case managers should address every step of the process, from admission to transfer to coronary care units.
PTCA preferred
At William Beaumont Hospital in Royal Oak, MI, PTCA is the treatment of choice for AMI, says director of the division of cardiology William O’Neill, MD. He says the most recent global use of strategies to open occluded arteries (GUSTO) trial indicates there is a more significant reduction in death or reinfarction in PTCA patients compared to thrombolytic therapy.2
In fact, at Beaumont, thrombolytic therapy is only used in a small number of patients who aren’t considered good candidates for PTCA. Virtually every patient who comes into the ED with electrocardiographic evidence of an acute infarction immediately goes to the cardiac catheterization lab for PTCA. Staff are on call around the clock in the cardiac catheterization lab. O’Neill estimates it takes about an hour for the patient to go from door to open artery in the cath lab.
"To me, the most compelling argument about angioplasty is that you almost eliminate the risk of having an intracranial bleed, which occurs about 1% of the time [with thrombolysis], and 60% of them are fatal," he says. "I think just from a pure safety advantage, [PTCA] is the preferred therapy."
But PTCA can’t be used in hospitals without a 24-hour cardiac catheter lab, he adds, and those labs aren’t feasible in smaller, less urban hospitals treating small numbers of patients. O’Neill stops short of recommending that hospitals open more cath labs so PTCA could be used on a broader basis, but he says door-to-treatment time can still be improved with thrombolysis.
"The most critical thing is to decrease the door-to-electrocardiogram time," says O’Neill. "We’ve found that’s often the longest delay. If a patient has a big laceration on his scalp and is bleeding, he’ll probably get treated right away. But if the patient is having a gnawing discomfort in his chest, he could be having a massive infarct, and he is just sitting in the waiting room waiting to be seen. The electrocardiogram (EKG) drives the whole system. Once the EKG is done and is rapidly interpreted, then the patient can be quickly treated."
O’Neill says the average time at Beaumont from admission to EKG is 12 minutes. In addition, the hospital has a segregated chest pain center that sees any patient with chest pain immediately upon entering the ED. "The same things that decrease the door-to-needle time decrease the door-to-cath time," he says.
If both therapies are offered, make sure time isn’t wasted trying to decide which one to provide, O’Neill adds. He recommends that "clear guidelines" be developed for either therapy. At Beaumont, these patients are preferred for thrombolysis over PTCA:
• those who have had an anterior wall MI demonstrable on EKG;
• those older than age 65;
• those with an admission heart rate of greater than 100.
Frederic Jones, MD, executive vice president for medical affairs at Anderson (SC) Area Medical Center, has been part of a team working to reduce door-to-treatment time for AMI. Presently, the average is about 40 minutes, he says. Like the majority of U.S. hospitals, his facility doesn’t perform PTCA.
"We have a very active catheterization laboratory, but we don’t have on-site [heart] bypass surgery," he notes. "A few hospitals have opted to do angioplasties without on-site bypass surgery, but that’s pretty controversial. We have elected to use a clinical practice guideline that emphasizes thrombolytic therapy."
Nevertheless, Jones says he doesn’t necessarily think thrombolysis is better than PTCA. "I think each patient should be individualized, and in those institutions that can [safely] provide it, angioplasty may be the best thing for the patients," he adds.
Jones says the hospital’s goal is to get angioplasty door-to-treatment time to within 30 minutes of arrival at the hospital, a recommendation made by the National Heart Attack Alert Program (NHAAP), which is part of the National Heart, Lung, and Blood Institute in Bethesda, MD.3 (See guidelines, p. 179.) He credits that low treatment time to cooperation between nursing, pharmacy, and ED physicians and to factors such as streamlined admissions for chest pain patients, EKG machines in the ED, and allowing ED physicians to administer thrombolytics.
Algorithmic approach adopted
Elaine Reimels, PhD, director of nursing at Anderson, says a flowchart outlines the care of patients with chest pain from presentation to the ED to transfer to the coronary care unit (CCU), if needed. (See algorithm from NHAAP, p. 180.) Clinical paths, which she refers to as "plans of care," haven’t been developed for the ED because those staff prefer following an algorithmic, step-by-step approach. A plan of care is in effect for AMI patients once they are admitted to the CCU.
"The [ED staff] felt they really needed more of an algorithm to follow instead of a plan of care, not only as tools to guide our practice, but also as documentation," says Reimels.
Time to treatment also has been accelerated at Anderson by improving nurse triage of patients, says Susan Blackburn, RN, MBA, coordinator of special projects and research at Anderson.
"The triage nurse’s recognition that the patient may be an MI patient is important," she notes. "So many of our patients come in with [only] shortness of breath or symptoms that aren’t typical. We empower the nurses so that if the patient has active chest pain, a cardiac history, or other signs, they should go ahead and get that EKG. They don’t wait until the physician sees the patient."
Other timesavers can be used
Other timesaving factors include the following:
• Whoever does the EKG hands the results immediately to a physician.
• Telephones are placed in rooms where AMI patients are held so physicians can call orders for thrombolytics immediately to pharmacy.
• Pharmacists know to stop whatever they are doing and prepare and deliver the thrombolytic agent to the ED.
"Pharmacists are instructed to hand the drug to an RN," Blackburn says. "They don’t just put it on the counter."
Since 1994, federal guidelines have recommended that door-to-treatment time for thrombolysis be within 30 minutes.3 "The whole point is to reduce delays and barriers to expedite time to treatment," says Mary Hand, MSPH, RN, coordinator of the NHAAP at the National Heart, Lung, and Blood Institute. (See related article, at right.)
In 1991, when the program was first begun, the average time was 60 to 70 minutes for patients to receive thrombolysis. Now it is 39 minutes. Further initiatives are planned to help patients recognize the symptoms of a heart attack sooner so they don’t delay getting to the ED for treatment.
The program doesn’t address PTCA. But Hand says these are four critical time points in the thrombolytic process:
• Door the time that a patient enters the ED. Protocols should be established to assess patients rapidly. EDs should have an explicit list of "chief complaints" that require immediate evaluation by a triage nurse.
• Data the time that an electrocardiogram is taken. An EKG should be obtained on potential heart attack patients within five minutes of when it is ordered.
• Decision the time that the decision is made to treat with thrombolytic therapy. All hospital medical staff responsible for treating AMI patients should jointly develop guidelines for initiating thrombolytic therapy.
• Drug the time thrombolytic therapy begins. ED physicians should have delegated authority to order thrombolytic therapy without having to obtain prior consultation.
[Editor’s note: Free copies of the National Heart Attack Alert Program recommendations can be ordered from the NHLBI Information Center, P.O. Box 30105, Bethesda, MD 20824-0105. Telephone: (301) 251-1222. Fax: (301) 251-1223.]
References
1. Lange RA, Hillis LD, Grines CL. Clinical debate: Should thrombolysis or primary angioplasty be the treatment of choice for acute myocardial infarction? New Engl J Med 1996; 335:1,311-1,317.
2. Ellis S. The GUSTO Iib angioplasty substudy. Presented at the American College of Cardiology Scientific Sessions. Orlando, FL; March 1996.
3. National Heart Attack Alert Program Coordinating committee, 60 minutes to treatment working group: Emergency department rapid identification and treatment of patients with acute myocardial infarction. Ann Emerg Med 1994; 23:311-329.
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