Latest European and US STEMI Guidelines Compared and Contrasted

November 06, 2009

November 6, 2009 (Boston, Massachusetts) — Two American doctors have published a paper detailing the most important recommendations in recently updated US and European guidelines for the management of ST-elevation MI [1].

"Although generally consistent with one another, differences between the guidelines exist due in part to new data that were released in the year between their publications and occasionally due to differing interpretations of the available data," say Drs Deepak Thomas and Robert P Giugliano (Brigham and Women's Hospital, Boston, MA) in the November 2009 issue of the American Heart Journal.

The latest US guidance for the management of STEMI was first published in 2007 as a focused update to the ACC/AHA 2004 guidelines, and the most recent European Society of Cardiology (ESC) advice appeared later, in 2008.

Guidelines Are Still Relevant

Asked by heartwire whether he thought guidelines were still pertinent, given the speed of publishing and reporting of new data, Giugliano said: "That's a very good question. The way I see it, I think the guidelines are even more relevant now; the data are coming so fast and furious it's extremely difficult for the average clinician and even experts to keep track of what's going on and have enough time to evaluate the information. And often it's conflicting, so it's a challenge just to keep up."

I think the guidelines are even more relevant now; the data are coming . . . fast and furious.

The time lag between studies being published and making their way into guidelines "allows the community time to read the research and digest it," he notes, adding, "We are probably better off adopting a Bayesian approach--incorporating the newest data on a background of all the other things we know, not just looking at the new findings in isolation." And guidelines "are usually in condensed format, with summaries in bold print and fairly specific conclusions, which means they are easier to go to as a source than 10 or 20 papers," he notes.

Both Discourage Facilitated Reperfusion, for the Time Being

Both the latest sets of guidelines on the management of STEMI suggest caution in the administration of intravenous beta blockers and avoidance of nonsteroidal anti-inflammatory agents and support a more aggressive approach to secondary risk-factor management, say Thomas and Giugliano.

Key aspects of the new updates are detailed guidance on the selection of a reperfusion strategy and the inclusion of newer adjunctive antithrombotic agents.

Both encourage a robust system to facilitate early diagnosis and reperfusion, with the ESC specifically advocating the setting up of a network of hospitals connected by an efficient ambulance service to aid optimal management of STEMI patients. And both caution against a facilitated reperfusion strategy, based largely on the ASSENT-4 and FINESSE trials.

But Thomas and Giugliano note that newer studies--CARESS in AMI, CAPITAL AMI, and TRANSFER AMI--have shown that routine transfer for early PCI after fibrinolytic therapy is associated with benefit. "The reasons for the discrepancy between the earlier studies and the three more recent studies . . . are not well understood," they observe. They suggest, however, that one contributory factor could be the longer delays between symptom onset and administration of fibrinolysis in the older studies.

So this is possibly one area "in which the guidelines might need to be updated," Giugliano told heartwire , with the Europeans seeming more keen to do so than the Americans, he added.

Both Endorse Newer Anticoagulants

The US and European guidelines also both make extensive recommendations with regard to four newer adjunctive parenteral anticoagulants as ancillary therapy to reperfusion in specific patients, depending on the mode of reperfusion.

"Although they differ a little bit in emphasis, the two guidelines are more similar than they are different when it comes to anticoagulants," Giugliano told heartwire .

Both consider it reasonable to treat STEMI patients who did not undergo reperfusion therapy with either low-molecular-weight heparin or fondaparinux for the duration of the index hospitalization, up to eight days maximum. The ESC further states that fondaparinux may be the preferred agent in this setting, on the basis of the OASIS-6 trial, and it notes "limited" evidence from the CREATE trial supports the use of reviparin in such patients.

Dosing of New Anticoagulants

Anticoagulant Patient characteristic Dosage
Enoxaparin <75 y 30-mg IV bolus followed by 1 mg/kg subcutaneously (sc) every 12 h
  >75 y No IV bolus; 0.75 mg/kg sc every 12 h
  Any age, creatinine clearance <30 mL/min 1 mg/kg sc every 24 hours
Fondaparinux Serum creatinine <3.0 mg/dL 2.5-mg IV followed by sc injections of 2.5 mg daily
Reviparin Weight <50 kg 3436 IU sc every 12 h
  Weight 50–75 kg 5153 IU sc every 12 h
  Weight >75 kg 6871 IU sc every 12 h
Bivalirudin   0.75 mg/kg IV bolus followed by an infusion of 1.75 mg/kg per hour during PCI

Differing Advice and Unique Recommendations

One issue the guidelines differ on is in their endorsement of routine elective coronary angiography after fibrinolysis: both note it would be "reasonable" to perform early angiography for risk stratification in patients not undergoing primary PCI, but the ESC goes a step further by supporting routine angiography (with PCI if indicated) three to 24 hours after successful fibrinolysis based on several recent studies, including the GRACIA trials.

Major recommendations unique to the US guidelines are a stepped approach to analgesia and a lower target international normalized ratio (INR) in patients receiving warfarin, aspirin, and clopidogrel. Unique advice from the Europeans includes measures to prevent/treat microvascular obstruction and reperfusion injury associated with PCI and a greater emphasis on maintaining euglycemia in STEMI patients.

With regard to secondary prevention, both the Americans and Europeans recommend an annual influenza vaccination in all patients, along with smoking-cessation counseling and advice to avoid passive smoking. Intensive LDL-cholesterol lowering is recommended, although the two sets of guidelines give slightly different long-term LDL targets. Also recommended are 30 to 60 minutes of moderate-intensity aerobic activity per day, as is clopidogrel for one year, irrespective of the acute treatment. Clopidogrel should be given for at least one month and ideally up to 12 months in those receiving bare-metal stents and 12 months in those who get drug-eluting stents.

Finally, the ACC/AHA supports the use of ACE inhibitors in revascularized patients with an abnormal EF but makes a less definitive recommendation for ACE inhibitors in those with a normal EF. Meanwhile, the ESC recommends ACE inhibitors in all STEMI patients without contraindications. And both guidelines advise an angiotensin-receptor blocker in case of ACE-inhibitor intolerance.

In conclusion, Thomas and Giugliano say: "The guidelines committees have taken into account a great deal of new data that have become available since the publication of the prior guidelines. It is imperative that healthcare providers who care for these [STEMI] patients become familiar with these updated recommendations. These evidence-based guidelines represent the most comprehensive and authoritative recommendations for the management of STEMI and are a critical tool for providers in their quest to provide optimal therapy for their patients."

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