ACC/AHA/SCAI guideline summary: Use of antithrombotic drugs in patients undergoing percutaneous coronary intervention (PCI)
Class I - Evidencia y consenso
[Bullet]  Unfractionated heparin (UFH).
[Bullet]  Bivalirudin or argatroban instead of heparin in patients with heparin-induced thrombocytopenia.
Class IIa - The weight of evidence or opinion is in favor of using antithrombotic drugs in patients undergoing PCI the following manner:
[Bullet]  Bivalirudin as an alternative to UFH and glycoprotein IIb/IIIa inhibitors elective PCI in low risk patients.
[Bullet]  Low molecular weight heparin (LMWH) as an alternative to UFH in patients with a non-ST elevation acute coronary syndrome.
Class IIb - The weight of evidence or opinion is less well established for the benefit of LMWH in patients undergoing PCI in the following setting:
[Bullet]  LMWH as an alternative to UFH in patients with ST elevation myocardial infarction.

Data from Smith, SC Jr, Feldman, TE, Hirshfeld, JW Jr, et al. ACC/AHA/SCAI 2005 guideline update for percutaneous coronary intervention a report of the American College of Cardiology/American Heart Association