Fibrinolytic therapy in patients with ST elevation MI (STEMI) has proven benefit. Furthermore, the beneficial effects of aspirin and clopidogrel as adjunctive therapy with fibrinolysis are well established and these agents should be given before or with the fibrinolytic.¹ Aspirin should be administered immediately if not already taken by the patient at home or administered by EMS before arrival. Based on available data, the optimal range of aspirin dose in patients treated with DAPT that provides maximal protection from ischemic events and minimizes bleeding risk appears to be 75 mg to 100 mg.² Since aspirin dose available in the United States is 81 mg, this maintenance dose is recommended in patients with coronary artery disease treated with DAPT. Data from the CLopidogrel as Adjunctive Reperfusion Therapy Thrombolysis in Myocardial Infarction (CLARITY [TIMI] 28 trial) suggested that adding clopidogrel to fibrinolysis is safe and effective in patients </=75 years of age.³ In this study, patients were randomly assigned in a 1:1 ratio to receive either clopidogrel 300-mg loading dose followed by 75 mg once daily or placebo in a double-blind fashion on top of baseline aspirin. By 30 days, clopidogrel therapy reduced the odds of the composite end point of death from cardiovascular causes, recurrent myocardial infarction, or recurrent ischemia leading to the need for urgent revascularization by 20 percent (from 14.1 to 11.6 percent, P=0.03). The recommendation that clopidogrel be continued for up to 1 year is extrapolated from the experience with DAPT in patients with non–ST-elevation ACS.⁴ The coadministration of other P2Y12 antagonists (prasugrel, ticagrelor) with fibrinolytic therapy has not been prospectively studied. An ongoing study Ticagrelor for PCI Post Thrombolysis (SETFAST) is evaluating the safety and efficacy of ticagrelor in patients undergoing PCI post fibrinolytic therapy for STEMI.

The 2016 ACC/AHA guideline focused update on duration of dual antiplatelet therapy in patients with coronary artery disease makes the following evidence-based recommendations.⁵

COR	LOE	Recommendations
I	A	In patients with STEMI treated with DAPT in conjunction with fibrinolytic therapy, P2Y12 inhibitor therapy (clopidogrel) should be continued for a minimum of 14 days (Level of Evidence: A)1,3 and ideally at least 12 months (Level of Evidence: C-EO).
	C-EO
I	B-NR	In patients treated with DAPT, a daily aspirin dose of 81 mg (range 75 mg to 100 mg) is recommended.2
IIb	A SR	In patients with STEMI treated with fibrinolytic therapy who have tolerated DAPT without bleeding complication and who are not at high bleeding risk (e.g., prior bleeding on DAPT, coagulopathy, oral anticoagulant use), continuation of DAPT for longer than 12 months may be reasonable.4

EO indicates expert opinion; NR indicates nonrandomized data; SR indicates systematic review

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References

1. Chen Z.M., Jiang L.X., Chen Y.P., et al; Addition of clopidogrel to aspirin in 45,852 patients with acute myocardial infarction: randomized placebo-controlled trial. Lancet. 2005;366:1607-1621.
2. Xian Y, Wang TY, McCoy LA, et al. The Association of Discharge Aspirin Dose With Outcomes After Acute 14 Myocardial Infarction: Insights From the TRANSLATE-ACS Study. Circulation. 2015; 132(3):174-81
3. Sabatine MS, Cannon CP, Gibson CM, et al. Addition of clopidogrel to aspirin and fibrinolytic therapy for myocardial infarction with ST-segment elevation. N Engl J Med 2005;352:1179-1189
4. Spencer FA, Prasad M, Vandvik PO, Chetan D, Zhou Q, Guyatt G. Longer- Versus Shorter-Duration Dual-Antiplatelet Therapy After Drug-Eluting Stent Placement: A Systematic Review and Meta-analysis. Ann Intern Med. 2015 Jul 21;163(2):118-26. doi: 10.7326/M15-0083.
5. Levine GN, Bates ER, Bittl JA, et al. 2016 ACC/AHA guideline focused update on duration of dual antiplatelet 12 therapy in patients with coronary artery disease: a report of the American College of Cardiology/American Heart 13 Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol 2015;

Keywords: Adenosine, Aspirin, Coronary Artery Disease, Double-Blind Method, Fibrinolysis, Myocardial Infarction, Thrombolytic Therapy, Ticlopidine, Platelet Aggregation Inhibitors

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