Following Acute Coronary Syndrome Guidelines Improves Outcomes

EDINBURGH, Scotland, May 1 -- For acute coronary syndrome patients, there seems to be a better way.

Changes in the management of such patients using the latest cardiology-society guidelines paid off with significant reductions in rates of heart failure, myocardial infarction, stroke, and death, revealed the multinational Global Registry of Acute Coronary Events (GRACE) study.

Among patients with ST-segment elevation myocardial infarction (STEMI), hospital deaths decreased from 8.4% to 4.6%, and for patients with non-ST elevated acute coronary syndrome, the rate of hospital deaths declined by approximately a quarter, according to a report in the May 2 issue of the Journal of the American Medical Association.

This study is the first to demonstrate that practice guidelines recommended by the American College of Cardiology, the American Heart Association, and the European Society of Cardiology translate into improved clinical outcomes, wrote Keith A. A. Fox, M.B., Ch.B., of the University of Edinburgh ,and colleagues.

The GRACE study was a multinational cohort study of 44,372 patients with an acute coronary syndrome. Patients were enrolled from 113 hospitals in 14 countries from July 1, 1999 through Dec. 31, 2006.

Of those patients, 27,558 had non-ST-segment elevation acute coronary syndrome, and 16,814 had STEMI. Patients with non-ST-segment elevation acute coronary syndrome had a more complex medical history than the STEMI patients, were less likely to be current smokers, but more likely to have quit smoking

There was a marked increase in interventional therapy in both groups of patients, the researchers noted.

The investigators also found increased use of beta-blockers, statins, ACE inhibitors or angiotensin II receptor blockers (ARBs), and thienopyridines in both groups of patients

For STEMI patients undergoing percutaneous coronary intervention there was also an increase in use of glycoprotein IIb/IIIa inhibitors. This increase was matched by a significant decrease in rates of death, cardiogenic shock, and heart failure, or pulmonary edema.

In patients with non-ST-elevation acute coronary syndrome, there were also increases in hospital treatment with low-molecular-weight heparin. In contrast to the STEMI group, the use of Gp IIB/IIIa inhibitors with or without percutaneous coronary intervention increased between 1999 and 2003, but changed little thereafter, the researchers said.

In the non-ST-elevation group, the researchers said, the rates of new heart failure or pulmonary edema decreased significantly. After adjustment for risk status, the rate of hospital deaths declined by about 25%.

The study findings included:

• Use of medications increased over the study period (beta-blockers, statins, angiotensin-converting enzyme inhibitors, thienopyridines with or without PCI, glycoprotein IIb/IIIa inhibitors, low-molecular-weight heparin; all P<.001).
• Pharmacological reperfusion declined in patients with STEMI by 22 percentage points (95% confidence interval, ?27 to ?17), whereas primary PCI increased by 37 percentage points (95% CI, 33-41).
• In non-STEMI patients, rates of PCI increased markedly by 18 percentage points (95% CI, 15-20).
• Rates of congestive heart failure and pulmonary edema declined in both populations: STEMI, ?9 percentage point (CI, ?12 to ?6) and non-ST-segment elevation acute coronary syndrome, ?6.9 percentage points (CI, ?8.4 to ?4.7).
• In STEMI patients, hospital deaths decreased by 3.9 percentage points (CI, ?5.3 to ?1.9) and cardiogenic shock by 2.4 percentage points (CI, ?4.3 to ?0.5).
• Risk-adjusted hospital deaths in non-ST-segment elevation acute coronary syndrome patients declined by 0.7 percentage point (CI, ?1.7 to 0.3). After adjusting for risk scores, which increased modestly over the course of the study, the rate of hospital deaths declined by approximately a quarter.
• Complications at six-month follow-up rates declined among STEMI patients: stroke by ?0.8 percentage point (CI, ?1.7 to 0.1) and myocardial infarction by ?2.8 (CI, ?6.4 to 0.9).
• In the non-ST-segment acute coronary syndrome group, six-month deaths declined by 1.6 percentage points (CI, ?3.0 to ?0.1) and stroke by 0.7 (CI, ?1.4 to 0.1).

Reviewing study limitations, the researchers wrote that the participating clusters represent regional practices and outcomes but do not necessarily reflect practice for specific countries.

It was not possible, they said, to determine whether improvements in adherence to evidence-based medicine are limited to the participating sites or are taking place throughout the respective countries.

Earlier, GRACE findings had emphasized hospital status, access to resources, and geographical factors, rather than the influence of new guidelines. However, Dr. Fox said, data from the current study, which included data through 2006, demonstrated substantial changes in the use of drug and interventional therapies in patients with acute coronary syndromes and clear evidence for a reduction in new heart failure and hospital deaths, especially in MI patients.

This and other evidence suggest the potential for further reduction in poor outcomes with greater use of evidence-based therapies and interventions, the researchers said.

Among financial disclosures, Dr. Fox reported receiving research grant funding from the British Heart Foundation, Medical Research Council, and the Wellcome Trust, and research grants and lecture fees from Sanofi-Aventis, GlaxoSmithKline, and Bristol-Myers Squibb.