New American College of Cardiology (ACC) and American Heart Association (AHA) guidelines released this week outline how patients with unstable angina and non-STEMI should be managed including the proper timing of acute interventional therapy, timing and duration of dual- antiplatelet therapy and the use of invasive techniques.
Jeffrey L. Anderson, MD, and other members of the writing group worked to update 2007 guidelines, which recommended clopidogrel ( Plavix, Bristol-Myers Squibb/ Sanofi-Aventis) one-year post-implantation of a drug- eluting stent (DES), proper blood pressure control and the stoppage of non-steroidal anti-inflammatory drugs during hospitalizations.
The current guidelines recommend that:
- Oral beta-blocker therapy be administered within the first 24 hours for patients who do not have one or more of the following conditions: signs of heart failure, evidence of a low output state, increased risk for cardiogenic shock or contraindications to beta blockade;
- For unstable angina and non-STEMI patients who have contraindications to beta-blockers, a calcium channel blocker should be given as the initial therapy if there is an absence of significant left ventricular dysfunction or other contraindications;
- ACE inhibitors should be administered within the first 24 hours to non-STEMI patients with pulmonary congestion or LVEF less than or equal to 0.40 with the absence of hypotension or contraindications to medications;and
- ARBs should be administered to patients who cannot tolerate ACE inhibitors.
Additionally, the guidelines outlined that a combination of aspirin, anticoagulant and additional antiplatelet therapy is the most effective therapy for unstable angina/non-STEMI patients. However, they urged that medical therapy should be tailored to the individual patient and that triple- antithrombotic treatment can be utilized in ischemia or high-risk patients presenting for an early invasive strategy.
The guidelines said that non-STEMI patients who are therapeutically anticoagulated with warfarin could be problematic and clinical judgment is necessary when administering anticoagulants and antiplatelets to this patient population.
While the writing committee said that clopidogrel should play an integral role in unstable angina and non-STEMI patients undergoing PCI, it may still be unclear how long the therapy should be maintained. However, the guidelines suggest that one year of dual-antiplatelet therapy is best for patients who are not at a high risk of bleeding. This may not be the case for all DES-treated patients.
For patients who are at an increased risk of stent thrombosis, renal insufficiency or who have multiple stents, dual- antiplatelet therapy may have room to be extended. The authors write however that “the optimal duration of anticoagulation therapy remains undefined.”
With a better evidence base, recommendations for the future management of unstable angina and non-STEMI patients could include:
- The development of heart attack centers to improve the treatment of MI;
- Intervention at shorter (less than six hours to 24 hours) rather than longer (greater than 48 hours to 96 hours) intervals in high-risk patients;
- Using a noninvasive treatment approach for low-risk patients;
- Better stratifying patients’ risk with the use of biomarkers or risk assessment algorithms;
- The potential administration of triple- antiplatelet therapy (aspirin, GP IIb/IIIa inhibitor and clopidogrel) over dual- antiplatelet therapy ( clopidogrel with aspirin);
- The use of platelet function testing to allow titration of the type, intensity and duration of antiplatelet therapy; and
- The potential use of triple- anticoagulation therapy (aspirin, a thienopyridine and warfarin).
Lastly, in terms of prevention, the writing committee recommends that screening for atherosclerosis using the “atherosclerosis test” (coronary artery calcium scoring or carotid intima-media thickness assessment) in intermediate risk patients.
“Progress in UA/NSTEMI remains uneven, with rapid evolution in some areas but slow progress in others,” the authors wrote. With “holes” in the current management of these patients, the authors noted that physicians and professional organizations need to develop a fully evidence-based management strategy for this patient population.
“Strategies must include not only innovations in diagnosis and treatment but also fresh approaches to motivating lifestyle changes, leading to