Improving outcomes for patients with acute coronary syndrome

May 2 2007

Recent changes in the recommended treatments used for patients hospitalized for acute coronary syndromes, such as a heart attack, are associated with reductions in the rates of heart failure, stroke, heart attack and death, according to a study in the May 2 issue of JAMA.

Randomized trials have provided strong evidence for the effectiveness of pharmacological and interventional treatments in patients with ST-segment elevation (a certain pattern on an electrocardiogram) and non-ST-segment elevation acute coronary syndromes (NSTE ACS), leading to changes in practice guidelines. "However, the extent and time course of changes in clinical practice are uncertain, and it is unknown whether such changes are associated with improved outcome. Previous studies have documented substantial gaps between guideline recommendations and clinical practice. Thus, there is a clinical priority to determine the extent to which evidence is applied in practice, whether this is changing over time, and whether such changes are associated with improved outcomes," the authors write.

Keith A. A. Fox, M.B., Ch.B., F.R.C.P., of the University of Edinburgh, Scotland, and colleagues with the GRACE Study (Global Registry of Acute Coronary Events) analyzed data from 44,372 patients with an ACS to determine if changes in hospital management of patients with ACS are associated with improvements in clinical outcomes. The patients were enrolled and followed-up between July 1999 and December 2006 at 113 hospitals in 14 countries.

The researchers found that the use of pharmacological medications increased over the study period (beta-blockers, statins, angiotensin-converting enzyme [ACE] inhibitors, thienopyridines with or without percutaneous coronary intervention [PCI], glycoprotein IIb/IIIa inhibitors, low-molecular-weight heparin). Use of pharmacological reperfusion in patients with ST-segment elevation myocardial infarction (STEMI) declined by 22 percentage points, whereas the rate of primary PCI increased by 37 percentage points. Approximately one-third of patients received primary or other PCI in 1999 and this increased to 64 percent of patients in 2005.

In patients with non-STEMI, rates of PCI increased by 18 percentage points. Rates of congestive heart failure and pulmonary edema declined in both populations. In patients with STEMI, hospital deaths decreased by 18 percentage points and cardiogenic shock decreased by 24 percentage points. Risk-adjusted hospital deaths declined in NSTE ACS patients, as did six-month death and stroke rates. Six-month follow-up stroke and heart attack rates declined among STEMI patients.

"These data, from the largest multinational observational cohort study of patients with an ACS, demonstrate clear evidence of a change in practice for both pharmacologic and interventional treatments in patients with either STEMI or NSTE ACS," the authors write. "The changes are consistent with trial evidence and national and international guidelines. The risk profile for patients with STEMI has not changed significantly over this interval, whereas the risk for patients with NSTE ACS has increased slightly. For the first time, we have demonstrated significant reductions in hospital rates of new heart failure in ACS patients, over time, and reductions in mortality.