Updated Unstable Angina/NSTEMI Guidelines Released by ACC & AHA

The AHA and ACC have released a focused update of the 2007 guidelines for the management of unstable angina and NSTEMI. The guidelines incorporate new information from recent clinical trials, and deal with controversial topics such as the timing and role of invasive therapy, the choice of antiplatelet agents, and the use of platelet-function and genetic tests with antiplatelet agents.

The document endorses the FDA label for prasugrel that states “that it is reasonable to consider selective use of prasugrel before catheterization in subgroups of patients for whom a decision to proceed to angiography and PCI has already been established for any reason” but also cautions clinicians about the “potential bleeding risks from prasugrel compared with clopidogrel.” The update also notes that another oral antiplatelet agent, ticagrelor, has not yet been approved by the FDA and is therefore not recommended for use but acknowledges that “it may have a future role in patients with UA/NSTEMI.”

The update includes a full discussion of platelet function and genetic testing for CYP2C19 allelles but does not include a recommendation for their use. Noting the absence of clinical trials to support platelet function tests, the update states that “the lack of evidence does not mean lack of efficacy or potential benefit, but the prudent physician should maintain an open yet critical mind-set about the concept until data are available from >1 of the ongoing randomized clinical trials examining this strategy.”

Regarding the use of PPIs with clopidogrel, the update agrees with a recent ACC statement that “does not prohibit the use of PPI agents in appropriate clinical settings, yet highlights the potential risks and benefits from use of PPI agents in combination with clopidogrel.”

An early invasive strategy within 12 to 24 hours of admission is recommended only for initially stabilized high-risk patients. For patients at lower risk a delayed invasive approach is “reasonable.”

The document also clarifies the use of dual antiplatelet therapy versus triple antiplatelet therapy and the role of invasive therapies in patients with advanced renal dysfunction.

Here is the press release from the ACC:

ACC/AHA Release Focused Update to the Guidelines for the Management of Patients With Unstable Angina/Non–ST-Elevation Myocardial Infarction

The American College of Cardiology (ACC) and the American Heart Association (AHA) today released a focused update to the 2007 guidelines for the management of patients with unstable angina (UA)/non-ST-elevation myocardial infarction (NSTEMI). This focused update allows clinical practice guidelines to keep pace with and respond promptly to the steady stream of new data on which previous diagnosis and care recommendations are based.

Unstable angina – which occurs when the heart doesn’t get enough blood flow and oxygen – causes chest pain and discomfort and occurs when the coronary artery is partially blocked. Myocardial infarction, or heart attack, is an acute manifestation of this condition, in which a coronary artery is completely blocked and cutting off blood flow to the heart.  The guidelines address the diagnosis and management of patients with UA and the related condition of NSTEMI.

“By taking another look at the guidelines, and creating a focused update, cardiologists are better able to target advanced therapies and interventional strategies to those at greatest risk,” said R. Scott Wright, M.D., professor of medicine and consultant in Cardiology and Acute Coronary Care at the Mayo Clinic, and lead author of the focused update. “We are in an era of incremental improvement in the treatment of patients with acute coronary syndromes. In the absence of a paradigm shift, the future will see incremental benefit as we learn to fine-tune the applications of therapies and revascularization. The challenge is to keep up with the fields of new data.”

According to the writing committee, there have been major advances in the management of UA/NSTEMI patients over the past three years that center on four important areas:

1.      The timing of acute interventional therapy in patients with non-ST-elevation myocardial infarction has been better clarified by a number of studies. Immediate catheterization and intervention does not offer a benefit over initial medical stabilization followed by early catheterization and intervention in all but the highest risk populations.
2.      The timing, duration and application of dual antiplatelet therapy and triple antiplatelet therapy have been clarified with further evidence supporting the role of triple antiplatelet therapy in high-risk patients and dual antiplatelet therapy in all other patients. Additionally, there are at least two thienopyridines that can be used as one of the two agents in dual antiplatelet therapy.
3.      The role and potential benefit of invasive therapies in patients with advanced renal dysfunction has been further clarified by data.
4.      Participation in a quality of care data registry designed to track and measure outcomes, complications, and adherence to evidence-based processes of care and quality improvement for UA/NSTEMI can drive quality improvement for acute coronary syndromes (ACS).

The 2007 guidelines put into practice an initial non-invasive set of preliminary tests; recommended the use of antiplatelet therapy clopidogrel for at least one year after receiving a drug-eluting stent; highlighted the importance of blood pressure control; and advised cessation of non-steroidal anti-inflammatory drugs (NSAIDS) use for all UA/NSTEMI patients during hospitalization.

The 2011 focused update incorporates late-breaking clinical trial results presented in 2008 and 2009, as well as selected data presented through April 2010 that may impact guideline recommendations. These include clarification of the timing and role of invasive therapy with ACS; which patient subgroups should have dual antiplatelet therapy versus triple antiplatelet therapy; and the role of invasive therapy in patients with chronic kidney disease.

The 2011 focused update also further incorporates the  risk-score risk analysis into clinical decision-making; platelet function and platelet genotype testing; the duration of thienopyridine therapy in patients treated with drug-eluting stents; and the clarification of renal function prior to use of contrast agents with diagnostic angiography. Lastly, the focused update promotes the use of quality of care registries and data repositories to promote quality and increased use of evidence-based medicine.

“While the analysis of standard practices is ongoing, this focused approach allows for continual review of new evidence and efficient implementation of important science and treatment trends that could have a major impact on patient outcomes and quality of care,” Wright said. “The clarification of timing and role of invasive therapy, as well as the ability or lack thereof for invasive therapy to offer a benefit in patients with advanced renal dysfunction, is a perfect example of the importance of continuous treatment guidelines review.”

The 2011 focused update will be published in the Journal of the American College of Cardiology and Circulation: Journal of the American Heart Association, and will be posted ahead of print on the ACC (www.cardiosource.org) and AHA (www.americanheart.org) web sites.

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