European and American guidelines: toward a global standard

Berlin, Germany — A global consensus is emerging about guidelines for treating patients with acute coronary syndromes (ACS).

Speaking at a symposium held during ESC 2002, "Treatment strategies to reduce ischemic events-the long-term management of atherothrombosis," leading cardiologists agreed that there are remarkable similarities between the new European guidelines for management of ACS without persistent ST-segment elevation and the American guidelines.

"It is actually testimony to the global trials that are now standard in developing and looking at new treatments," said Dr Christopher Cannon (Harvard Medical School, Boston). "We are developing global standards of care."

Dr Michel Bertrand (University of Lille, France), who served as Chairman of the ESC task force on management of ACS without persistent ST-segment elevation, said that there were major similarities and only minor differences between the European and American guidelines.

Clopidogrel plus ASA: baseline, long-term therapy

Dr Bertand pointed out that the new ESC guidelines, presented at the ESC congress, recommend the use of clopidogrel on top of ASA as baseline therapy and as long-term treatment for 9 months, possibly 12 months.

Outlining the ESC guidelines on the evaluation, stratification, and management of ACS patients Dr Bertrand said that after clinical examination it is necessary to record an ECG followed by ST-segment monitoring. Blood samples should be obtained to determine Troponin T or I and CK-MB. The ESC guidelines call for risk stratification into 2 categories of patients: high-risk patients, and low-risk patients. (The American guidelines call for 3 categories of risk).

Dr Bertrand emphasized that diabetics have been added to the group of high-risk patients, including those with persistent or recurrent ischemia, ST-segment depression, elevated troponin, and hemodynamic or arrhythmic instability. On top of baseline treatment, these patients require infusion of IIb/IIIa receptor inhibitors followed by coronary angiography within the hospitalization period.

He said that patients with suitable lesions for PCI will receive clopidogrel, which also will be given to patients with coronary lesions not suitable for any form of revascularization. Patients scheduled for CABG will not receive clopidogrel, except if the operation is postponed but in that case, clopidogrel should be stopped at least 5 days before operation. Clopidogrel should also be stopped if the coronary angiogram is completely normal.

The ESC guidelines define low-risk patients as those with no recurrent chest pain, T-wave inversion, flat T-waves or normal ECG, and negative troponin. In such cases, troponin should be repeated in 6 to 12 hours. If this examination is twice negative, heparin may be discontinued, while ASA, beta blockers, and nitrates are continued, and clopidogrel is given. Before discharge, or in the following days if this is not possible, a stress test will be performed to assess the probability and severity of coronary artery disease. Following this examination, a coronary angiography may be performed.

Risk factor management

These guidelines call for aggressive management of risk factors: no smoking, regular exercise, ASA, clopidogrel for at least 9 months, beta-blockers (if no contraindication), and statins to be continued during the follow-up.

In his presentation, Cannon said: "The ACC/AHA guidelines as updated in 2002 mirror the ESC guidelines." He said that these guidelines are becoming a global standard of treatment approaches for this large group of patients.

From evidence-based guidelines to practice

Cannon called on cardiologists to translate the guidelines, based on evidence from randomized trials, into clinical practice. He cautioned against being guided by observational studies rather than randomized trial data.

"We have to do our best to try to apply these therapies from the guidelines to make sure that we get the benefit to each of the patients that we see," he said. "We have a global consensus on the optimal management of patients with unstable angina and non-ST-elevation MI.

Stroke and MI: long-term risks

In a separate presentation, Dr Mark Alberts (Northwestern University, Chicago) outlined a neurologist's perspective on the long-term treatment of atherothrombosis. He said that the prevalence of cerebrovascular disease is increasing throughout the western world.

He pointed out that 5 years after a stroke, more patients die of cardiovascular disease than die from stroke. He also said that the occurrence of stroke after MI is far higher than previously appreciated. Epidemiological studies have demonstrated that the long-term risk of a stroke patient having a cardiovascular event is much greater than the risk of having another stroke.

Stroke and CAD are different manifestations of the same underlying process, according to Alberts. He said atherothrombosis accounts for the majority of strokes.

In the future, he suggested, the ongoing MATCH study will provide key data about the safety and efficacy of combination therapy using clopidogrel on top of ASA in patients with ischemic stroke or TIAs. The MATCH study is an international, randomized, multicenter, double-blind placebo-controlled clinical trial comparing clopidogrel alone and clopidogrel on top of ASA. The study has closed enrollment and results are expected in 2004.

Pat Phillips