By Deborah Josefson, Nebraska
Primary coronary artery angioplasty, which is known to be superior to thrombolytic therapy in restoring blood flow to an ischaemic heart, can be safely implemented in hospitals that lack pre-existing angioplasty programmes and on-site cardiac surgery departments, a new study has found.
The report further suggests that treatment of acute myocardial infarction should be re-organised according to a trauma care model so that patients who have had a heart attack are preferentially directed to a facility where angioplasty is available (JAMA 2002;287:1943-51).
Although about 1.2 million Americans a year have heart attacks, 66% of them do not have access to hospitals that perform coronary angioplasty. Most community hospitals in the United States do not offer angioplasty despite the availability of trained interventional cardiologists and cardiac catheterisation facilities on-site, because in 1993 both the American College of Cardiology and the American Heart Association advised against the performance of angioplasties if cardiac surgery was not also available on-site.
This recommendation stemmed from the fear that angioplasties might lead to complications such as dissections, emboli, and acute occlusions without the possibility of correcting them with emergency cardiac surgery.
Because many previous studies have shown that angioplasty is superior to thrombolysis in achieving reperfusion, researchers from the Atlantic Cardiovascular Patient Outcomes Research Team sought to compare thrombolysis with angioplasty and to challenge the convention that has restricted angioplasty to medical centres with in-house cardiac surgery facilities. The researchers were led by Dr Thomas Aversano of the Johns Hopkins Medical Institutions in Baltimore, Maryland.
Before enrolling patients into the study, the investigators set up in each of the hospitals an angioplasty development programme, which provided a crash course in angioplasty care, trained staff, and set up quality control and management standards. The cardiologists who performed the angioplasties did, however, have previous experience in the technique and had to have done at least 50 of the procedures annually.
Inclusion criteria included chest pain lasting more than 30 minutes but less than 12 hours, age 18 years or more, ability to sign informed consent, and eligibility to receive thrombolytics and radiographic dye. Additionally, electrocardiographic changes diagnostic of myocardial infarction had to be present.
Patients with reduced creatinine clearance (creatinine over 1.5 mg/dl (124 m mol/l) in men or over 1.4 mg/dl in women) were excluded but comorbidities including previous myocardial infarction and previous bypass surgery and angioplasty were allowed in the study.
A total of 451 patients with acute myocardial infarction recruited from 11 community hospitals in Massachusetts and Maryland over three years were randomised into either a primary angioplasty arm or a thrombolytic arm with tissue plasminogen activator (tPA). Participants in both arms received aspirin immediately on presentation. Participants in the thrombolytic arm were started on tPA within 30 minutes of diagnosis and received heparin after thrombolysis for 48 hours.
In the angioplasty arm, the goal was to start balloon angioplasty within 90 minutes of arrival and to have the participants in the catheterisatiaon laboratory within an hour. Angioplasty was not done in patients who had clinical and electrocardiographic resolution of their ischaemia and normal flow on initial angiography.
The researchers found that at six months, the odds ratio for the composite end point (occurrence of death, recurrent myocardial infarction, or stroke) was 0.57 (95% confidence interval 0.34 to 0.95) in favour of angioplasty.
At six months, participants in the angioplasty arm experienced fewer complications and lower death rates than those in the thrombolytic arm. Mortality was 6.2% in the angioplasty cohort and 7.1% in the thrombolytic arm.
Moreover, 10.6% of those who received thrombolytics went on to develop another heart attack by six months, compared with only 5.3% in the angioplasty group. Strokes occurred in 4% of the thrombolytic group but in only 2.2% of the angioplasty group. Length of stay in hospital was also shorter in the angioplasty group—4.5 days v 6 days.
In a press release, Dr Aversano stated that he believed that healthcare policy should be amended to provide angioplasty to more patients. “It should not be a matter of chance or geography that determines what kind of care a heart attack patient receives,” he said.
In an accompanying editorial (pp 1987-9), Dr Christopher Cannon of the Brigham and Women’s Hospital in Boston, Massachusetts, agreed with the study’s overall findings and suggestions but pointed out that the study was small and that to be truly effective the provision of angioplasties would have to be available 24 hours a day.
Source: BMJ 2002;324:996 ( 27 April )