Heart attack drug 'can kill'

Clot-busting drugs may be a threat to elderly people

A drug commonly used to treat heart attack victims may actually increase the risk of death among elderly patients, research has revealed.

However, a UK expert has warned against making changes to current clinical practice on the back of one, not necessarily representative, study.

Researchers at Johns Hopkins University, in Baltimore, USA, tested the impact of intravenous thrombolytics, given to dissolve clots in the blood vessels serving the heart.

They found that patients older than 75 were nearly 40% more likely to die within 30 days of treatment than their counterparts who were not given the medication.

Lead researcher Dr David Thiemann said: "There has been a widespread belief that clot-busting drugs help older patients just as they do younger ones, but the evidence always has been equivocal and the question had never been directly tested until now.

The one-third of heart attack patients who are older than 75 are unlikely to have any benefit and may be at higher risk of death

Dr David Thiemann, Johns Hopkins University

"We found that in actual clinical practice the effectiveness of these drugs varies markedly with age.

"Younger patients clearly benefit from thrombolytics, but the one-third of heart attack patients who are older than 75 are unlikely to have any benefit and may be at higher risk of death."

Dr Thiemann said more studies on how to treat the older population were urgently needed.

Large study

The study used data on 7,864 patients aged 65 to 86, who arrived at hospitals with an acute heart attack and who were candidates for clot-dissolving therapy.

This data is not sufficient to change clinical practice

Professor Philip Hannaford, Aberdeen University

There were 5,191 patients aged 65 to 75 and 2,673 patients aged 76 to 86.

Patients aged 65 to 75 who received thrombolytic therapy had a 30-day death rate of 6.8%, compared with 9.8% for patients who did not get the medication.

Among patients aged 76 to 86 years, the pattern was reversed.

The death rate for patients treated with thrombolytics was 18%, compared with 15.4% for patients who did not receive the drug.

Dr Thiemann says there are several possible reasons for differences between the new findings and the conventional wisdom, which was based on research trials of clot-busting drugs conducted about a decade ago.

"Patients in general clinical practice are older and sicker than the selected patients enrolled in research trials, so deaths from major side effects such as stroke, bleeding and cardiac rupture may be more common," he said.

"In addition, hospitals do not always adhere to the rigorous protocols that govern research trials, so the results in actual nation-wide practice may be different."

Cardiac care expert Professor Philip Hannaford, of the department of primary care at Aberdeen University, echoed the concerns that the data might not be representative of the population as a whole.

He said that standard practice in the UK was to assess all heart attack patients for suitability for thrombolysis irrespective of their age.

The treatment is usually only denied to patients who have other medical conditions such as a bleeding ulcer, or a stroke.

Professor Hannaford said: "This data is not sufficient to change clinical practice."

A spokesman for the British Heart Foundation said: "Doctors need to weight up the pros and cons of a treatment such as clot-busting drugs on the basis of clinical need.

"It is too simplistic to decide on a course of treatment merely by a patient's age.

"We need to consider the factors or mechanisms that may be causing these death rate differences, such as patients' underlying conditions, and looking at these to decide on the most appropriate treatment for each individual patient.

"Randomised trials are obviously the next step to assess whether there should be a change in how thrombolytes are used."

The research is published in Circulation, an American Heart Association journal.