NEW YORK, Jan 10 (Reuters) -- The more frequent use of aggressive therapies helps patients in the U.S. survive shock after a heart attack better than patients elsewhere in the world, say British researchers.
"Patients treated in the USA had significantly lower mortality at 30 days and one year than patients who were treated in other countries," write the authors of an international study that looked at the results of the treatment of 40,000 patients after a heart attack.
More than half of the patients surveyed in the study were treated in the U.S., with the remainder treated in 14 other countries. Researchers tracked one-month and one-year survival patterns, along with methods of treatment, in an effort to compare survival rates. They looked closely at those experiencing a condition known as cardiogenic shock -- an often fatal condition involving a drop in blood pressure after heart attack.
The result? Cardiogenic shock led to death within one month in 50% of U.S. heart attack patients that made it to the hospital, but this record is better than that found among patients treated outside the U.S., where 66% of patients died within 30 days.
And the difference in mortality remained at one year -- "56% of patients treated in the USA died versus 70% of patients treated elsewhere," the researchers report.
The study authors found that geography is an important factor in surviving cardiac shock after a heart attack. In fact, they say the study showed that only "age and systolic blood pressure were... more strongly associated than geographical location with increased mortality."
"Patients with cardiogenic shock in the USA undergo more aggressive interventions, both diagnostic and therapeutic," researchers said. They found that procedures such as cardiac catheterization, bypass surgery, and angioplasty were more often used in the U.S. than in other countries. Medications, such as beta blockers, were prescribed more frequently by U.S. physicians as well, researchers say.
"We cannot say for certain that the difference between the USA and other countries was the result of more aggressive treatment strategies," say the study authors, but they note that other studies have shown "that early revascularization (bypass surgery, for example) is associated with better outcome."
Available technology may play a role as well. "Differences... may partly reflect the facilities available at different hospitals," the study concludes.
"In addition, the attitudes of patients, physicians, and society towards treatment for patients with emergency medical conditions may also be important factors," write the researchers.
SOURCE: The Lancet (1997;340:75-78)
