News

Delayed heart attack treatment may increase risk of death

June 04, 2010

By Patricia Nicholson

In a recent study, patients who were treated for heart attacks outside of the recommended treatment time had a significantly higher mortality rate after 30 days, compared to patients who were treated in the recommended time.

Researchers in Quebec studied the cases of 1,832 patients at 80 Quebec hospitals who were treated for ST-elevation myocardial infarction (STEMI) – one of the major types of heart attack, usually caused by a blocked coronary artery preventing blood from reaching the heart. All of the patients required treatment to open the blocked artery, but more than half were treated after the recommended time limit had elapsed. These patients had double the risk of dying within one month compared to those treated within time limits.

Recommended treatments for STEMI include medications and surgical approaches that restore blood flow to the heart. Medications such as clot-busting drugs can break up the clot that is blocking the artery. A type of surgery known as primary percutaneous coronary intervention (PPCI), often called angioplasty or ‘balloon’ angioplasty, opens blocked arteries by inserting a tube into the artery and inflating a balloon on the end of the tube to remove the blockage.

The longer the blood flow is interrupted, the more damage is done to the heart muscle. That’s why guidelines recommend that clot-busting medications be used with 30 minutes of diagnosis, and balloon angioplasty be performed within 90 minutes of diagnosis.

In the Quebec study, 392 patients received medication and 1,440 people had angioplasty. The majority of angioplasty patients (65 per cent) had to be transferred to another hospital to receive the procedure. These patients were more likely to receive late treatment.

More than half of the medication patients (54 per cent) and two-thirds of the angioplasty patients (68 per cent) were treated outside of the recommended time periods.

The 30-day mortality rate in all patients treated outside the time limits was 6.6 per cent, compared to 3.3 per cent for those treated within time limits.

Patients treated late also had a significantly higher risk of serious complications, such as hospital readmission or death, within one year.

The study, which was published in JAMA on June 2, 2010, highlights the importance of timely treatment for heart attacks.

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