Shirlyn McKenzie, PhD, University of Texas Health Science Center at San Antonio, and I developed the following summary for the clinical applications of anticoagulant therapy. Dr. McKenzie will use this for a PA lecture. Please review and offer your suggestions, corrections, or updates.
Percutaneous intervention (PCI, cardiac catheterization): use IV anti-glycoprotein IIb/IIIa agent during procedure such as tirofiban, abciximab, or eptifibatide. Follow up with unfractionated heparin (UFH) acutely, switch to anti-platelet drugs aspirin, 81 mg/day and plavix 75 mg/day. Continue plavix 6 months to 2 years, aspirin indefinitely. The PCI docs do not like receiving patients who have had fibrinolytic therapy, it raises bleeding risk during the procedure.
Coronary artery bypass graft surgery (CABG): use high-dose unfractionated heparin during surgery, follow with the ACT, then switch to anti-platelet drugs as for PCI, same dose and duration.
Chronic atrial fibrillation: Coumadin, start at 5 mg/d (2 mg/d if over 70), then adjust dosage to INR, use indefinitely to reduce risk of stroke. Use dabigatran (Pradaxa), rivaroxaban (Xarelto), or apixaban (Eliquis, when FDA-cleared) if Coumadin is difficult to control or causes side effects, or if insurance will pay and patient agrees.
Prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE) after orthopedic or neurological surgery or other situations associated with high risk of thrombosis such as medical condition with prolonged immobilization: Coumadin for three to six months or low molecular weight heparin (LMWH, Lovenox) for 14 days. Rivaroxaban is recently cleared for this purpose.
Treatment of acute DVT or PE: Treat acutely with UFH while inpatient, switch to Coumadin, or if not tolerated, Lovenox. At least six months, longer if risks remain high. My fellow bass in the church choir had bilateral PE with at least 20 clots throughout his lungs, he’s on Coumadin for life. Rivaroxaban is now cleared for this also, but not dabigatran.
The current key reference for anticoagulant therapy is Holbrook A, Schulman S, Witt DM, et al. Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):152S–84S. Review.