WASHINGTON, DC -- November 23, 2009 -- A collaborative, fast-track update to 2 sets of clinical guidelines calls for community-wide coordination of emergency services so that patients having a myocardial infarction (MI) receive the most effective treatment as quickly as possible.
The new document also lays out several new treatment options, not only for patients who are experiencing a MI but also for those who undergo angioplasty and stenting to open clogged coronary arteries.
The new guidelines update is a joint effort of the American College of Cardiology (ACC), the American Heart Association (AHA), and the Society for Cardiovascular Angiography and Interventions (SCAI). It simultaneously brings focused updates to 2 separate clinical guidelines, one on the management of patients with ST-elevation myocardial infarction (STEMI) and the other on percutaneous coronary intervention (PCI).
"The focused update is a way of responding quickly to new information that will benefit patients," said Sidney C. Smith, Jr., MD, Center for Cardiovascular Science and Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. "We were able to look over a year of major studies and incorporate the most valuable findings into the existing guidelines."
One of the most important new recommendations is for each community to develop an organised system of emergency care for patients who are having a MI, modeled after the AHA's Mission: Lifeline initiative and the ACC's Door-to-Balloon (D2B) campaign.
This plan would include protocols for identifying MI patients even before they reach the hospital and directing ambulances to medical centres capable of rapidly performing PCI to open the blocked coronary artery.
The plan would also include protocols for managing MI patients who initially arrive at hospitals not equipped to perform PCI, including arrangements for rapid transfer to a PCI center, whenever possible.
In addition, the guidelines address the management of patients who initially go to a non-PCI hospital and cannot be transferred quickly. These patients should be treated with clot-busting drugs, according to the guidelines. Afterward, if patients are judged to be high-risk, it is reasonable to transfer them to a PCI centre without delay, rather than waiting to observe whether the clot-busters are successful, as is common practice today.
Another major change in the guidelines is greater acceptance of stenting for the treatment of the left main coronary artery. Because a complete blockage of the left main coronary artery would cut off the blood supply to the majority of the heart, bypass surgery has long been the recommended treatment for patients with a narrowing in this artery. Recent studies, however, have shown that in certain patients, stenting of the left main is safe and effective. As a result, the new guidelines now allow for left main stenting as an option when procedural complications are likely to be low and the patient faces an increased risk if treated surgically.
"There is mounting evidence that stenting of the left main coronary artery, under certain circumstances, does carry a reasonably good outcome," said Spencer B. King, III, MD, Saint Joseph's Heart and Vascular Institute, and Emory University School of Medicine, Atlanta, Georgia. "Now stenting might be considered, based on the specific anatomy of the coronary arteries and the risk profile of the patient."
The guidelines update incorporates several additional changes, including the following:
· Use of a pressure wire threaded into the coronary artery to gauge whether plaque build-up in a particular area is actually interfering with blood flow. This assessment of fractional flow reserve helps interventional cardiologists pinpoint which coronary obstructions need to be widened with a stent and which do not.
· Use of aspiration thrombectomy, a technique in which the clot causing a MI is sucked out through a catheter before a stent is placed.
· Use of prasugrel as an alternative to clopidogrel for patients treated with PCI.
· Recommendations for use of a variety of blood thinners and anti-clotting medications before, during or after PCI.
· Broader recommendations on the types of x-ray dye that may be safely used to view the coronary arteries during PCI in patients with chronic kidney disease.
SOURCE: American College of Cardiology
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