Drug | Indication | Dosage | Comments |
Dextran sulfate | High-risk surgery patients at risk for thromboembolism | Dextran 40 (10% solution) 500 ml IV q3d during prolonged bedrest | More costly than other antithrombotic agents Inhibits platelet function and fibrin polymerization Contraindicated in established venous thromboembolism and in patients with heart failure or dextran hypersensitivity No more effective than warfarin or heparin in general surgery patients |
Heparin sodium | Venous thrombosis (general) Venous thrombosis (perioperatively for most abdominal, thoracic, or urologic procedures) | Fixed low dose 5,000 U SC q8 12h Fixed low dose 5,000 U SC 2 h prior to surgery, then 5,000 U SC q8 12h 5 7 d, or Continuous infusion 1 U/kg/h at surgery, then for 3 5 d after surgery |
Maintaining patency of indwelling venous catheters | 1 ml (10 100 U/ml) after each use of catheter or q4 8h | Withdraw at least 1 ml from catheter prior to flush |
Dalteparin sodium | For prevention of postoperative deep vein thrombosis in patients undergoing abdominal surgery who are at moderate to high riska,b,c of thromboembolic complications | Moderate high riska,b: 2,500 units daily deep SC (not IM) 1 2 h prior to surgery, then qd for 5 10 d High-very high riskb,c: initial dose 5,000 units SC prior to surgery or 2,500 units 1 2 h prior to surgery, followed 12 h later by 2,500 units SC After initial dose, 5,000 units SC qd 5 10 d | Low molecular weight heparin, porcine derived, each mg = 156.25 anti-Factor Xa International Units Dosage adjustment and routine monitoring of coagulation parameters are not necessary At recommended doses does not affect platelet aggregation fibrinolysis, prothrombin time, thrombin time, activated partial thromboplastin time Pharmacology differs from heparin or other low molecular weight heparins and is not interchangeable on a unit-for-unit basis Dosage adjustments in renal and hepatic disease have not been established; use with caution Use with care in patients receiving oral anticoagulants and/or platelet-aggregation inhibitors |
Enoxaparin sodium | For prevention of postoperative deep-vein thrombosis in patients undergoing hip replacement surgery | 30 mg deep SC bid, initial dose given as soon as possible after surgery but not more than 24 h postoperatively Given for 7 10 d | Low molecular weight heparin; porcine-derived Daily monitoring of the therapeutic effect is not necessary during therapy if laboratory indices of coagulation are normal prior to hip surgery At recommended doses, does not affect platelet aggregation or global-clotting tests (PT, aPTT) Pharmacology differs from heparin or other low molecular weight heparins and is not interchangeable on a unit-by-unit basis Adjust dose in renal disease Dosage adjustment in hepatic disease has not been established Use with care in patients receiving oral anticoagulants and/or platelet-aggregation inhibitors |
Fondaparinux | Prevention of deep venous thrombosis after hip fracture surgery or hip replacement | 2.5 mg daily SC, usually started 4 8 h postoperatively and treated for 5 9 d | Synthetic heparin analog that increases factor Xa inhibition without neutralizing thrombin Does not bind platelet factor IV, does not cause immune-mediated thrombocytopenia No effect on PT, aPTT time, bleeding time, or platelet function Renal clearance Not recommended if creatinine clearance <30 mL/min, platelets below 100,000/ L, or weight <50 mg Bleeding most common adverse effect especially if given less than 6 h after surgery |
Warfarin |
Therapy and prophylaxis | Venous thrombosis and pulmonary embolism | 10 15 mg PO qd 2 5 d, then 2 10 mg PO qd Coagulation end point for therapy: 1.3 1.5 control PT (INR 2 3)d | Indirect anticoagulant; alters synthesis of vitamin K dependent coagulation factors II, VII, IX, and X; use for follow-up anticoagulation after heparin Requires 2 7 d of therapy to deplete coagulation factors and to initiate anticoagulant effect; should overlap with heparin therapy by 4 5 d Multiple drug interactions (see Table 13.2) Cautions: (a) hemorrhage: if minor, hold and reduce dose; if moderate or severe, reverse with phytonadione, fresh frozen plasma, factor IX complex and/or rFVIIa (Table 8.2); (b) necrosis of skin or other tissues (especially in females and in protein C deficiency): treat with phytonadione and heparin |
Rheumatic mitral valve disease - if history of systemic embolism, or paroxysmal or chronic atrial fibrillation, or sinus rhythm with left atrium diameter >5.5 cm
- if recurrent systemic embolism despite adequate warfarin
| INR target 2.5 (range 2.0 3.0) INR target 2.5 (range 2.0 3.0) and aspirin PO 80 100 mg/d or INR 2.5 3.5 and dipyridamole PO 400 mg/d or clopidogrel |
Mitral valvuloplasty | Warfarin for 3 wks prior to procedure and 4 wks after the procedure. INR target 2.5 (range 2.0 3.0) |
Mitral valve prolapse - with documented but unexplained TIA
- with systemic embolism, chronic or paroxysmal atrial fibrillation, or recurrent TIAs despite aspirin therapy
| Aspirin 50 162 mg/d
INR target 2.5 (range 2.0 3.0) |
Mitral annular calcification with non-calcific embolism and associated atrial fibrillation | INR target 2.5 (range 2.0 3.0) |
Aortic valve disease | Low incidence of systemic embolism unless concomitant mitral valve disease, atrial fibrillation, or history of systemic emboli |
Aortic valve disease with mobile aortic atheromas and aortic plaques >4mm by TEE | Consider warfarin therapy |
Prosthetic heart valves/mechanical heart valves | All patients with mechanical heart valves should receive warfarin Unfractionated heparin or LMWH should be used until the INR is stable and therapeutic for 2 consecutive days |
St. Jude Medical bileaflet valve (aortic position) | INR target 2.5 (range 2.0 3.0) |
Tilting disk valves and bileaflet mechanical valves (mitral position) | INR target 3.0 (range 2.5 3.5) |
CarboMedics bileaflet valve or Medtronic Hall tilting disk mechanical valves (aortic position, normal left atrium size, sinus rhythm) | INR target 2.5 (range 2.0 3.0) |
Mechanical valve and additional risk factors (atrial fibrillation, myocardial infarction, left atrial enlargement, endocardial damage, low ejection fraction) | INR target 3.0 (range 2.5 3.5) with low dose aspirin, 75 100 mg/d |
Caged ball or caged disk valves | INR target 3.0 (range 2.5 3.5) with low dose aspirin, 75 100 mg/d |
Mechanical valves with systemic thromboembolism despite therapeutic INR | INR target 3.0 (range 2.5 3.5) with low dose aspirin, 75 100 mg/d |
Mechanical valves in whom warfarin must be discontinued | LMWH or aspirin 80 100 mg/d |
Bioprosthetic valve replacement | Heparin or LMWH until INR stable for 2 consecutive days |
First 3 months after valve insertion |
mitral position | Warfarin INR target 2.5 (2.0 3.0 range) |
aortic position | Warfarin INR 2.5 target (2.0 3.0 range) or aspirin 80 100 mg/d |
bioprosthetic valves with a history of systemic embolism | Warfarin for 3 to 12 months |
bioprosthetic valve with evidence of left atrial thrombus at surgery | INR target 2.5 (range 2.0 3.0) |
Bioprosthetic valve with atrial fibrillation; long-term treatment | INR target 2.5 (range 2.0 3.0) |
Bioprosthetic valves with sinus rhythm; long-term treatment | Aspirin 75 100 mg/d |
PFO and atrial septal aneurysm with unexplained systemic embolism or TIAs and venous thrombosis, or pulmonary embolism | INR target 2.5 (2.0 3.0 range) until venous interruption or closure of PFO |
Antithrombotic therapy in atrial fibrillation | Risk factors for thrombosis are: previous TIA or stroke, hypertension, heart failure, diabetes, clinical coronary artery disease, mitral stenosis, prosthetic heart valves, or thyrotoxicosis |
- if age < 60 y with no risk factorsd
| Aspirin 325 mg/d |
- if age < 60 y with heart disease and no risk factors
| Aspirin 325 mg/d |
- if age > 60 y with no risk factors
| Aspirin 325 mg/d |
- if age > 60 y with diabetes or coronary disease
| INR 2.0 3.0 with optional addition of aspirin 81 162 mg/d |
- if heart failure ejection fraction <.35, thyrotoxicosis, hypertension
| INR 2.0 3.0 |
- if age > 75 y, especially women, with or without risk factors
| INR 2.0 3.0 |
- with cardioversion if atrial fibrillation more than 2 d in duration
| INR 2.0 3.0 for 3 w before elective cardioversion and then continued for 4 weeks |
Infective endocarditis | Continue anticoagulant therapy because of high frequency of systemic thromboembolism but increase risk of intracranial hemorrhage |
- in patients with mechanical prosthetic valves
|
Nonbacterial thrombotic endocarditis | Heparin therapy (see above) |
- with systemic or pulmonary emboli
|
Disseminated cancer with aseptic vegetations | Full dose unfractionated heparin |
aPTT, activated partial thromboplastin time; INR, International Normalized Ratio; ISI, International Sensitivity Index; IV, intravenous; IM, intramuscular; PFO, patent foramen ovale; PO, by mouth; PT, prothrombin time; SC, subcutaneous; TIA, transient ischemic attacks; TEE, transesophageal echo Recommendations based in part on 7th ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004;126:3(Suppl):457S 482S. aPatients at risk for thromboembolic complications who are undergoing abdominal surgery are 40 years of age, obese, or in whom surgical procedure requires general anesthesia greater than 30 minutes in duration. bAdditional risk factors include malignancy, history of deep-venous thrombosis, or pulmonary embolism. cOther risk factors: prolonged immobility or paralysis, varicose veins, heart failure, myocardial infarction, fractures of the pelvis, hip, or leg, possibly high-dose estrogen therapy, and hypercoagulable states. dThe International Normalized Ratio (INR) is used to monitor warfarin therapy. The INR is intended to standardize prothrombin time (PT) reporting by minimizing the variability that can result from differences in the sensitivity of the thromboplastin reagent used to perform the PT test. The sensitivity of the thromboplastin reagent is measured by the ISI, which is referenced to a World Health Organization (WHO) reference standard. The INR is calculated as follows: (patient PT/mean normal control)ISI. The INR adjusts for differences in sensitivity of the thromboplastin reagent and reflects the result that would be obtained with the WHO reference thromboplastin. |