CASE HISTORY • Part 1
A 57-year-old woman, scheduled for an elective hysterectomy, is referred for management of her anticoagulation during the perioperative period. She is currently receiving warfarin 3 mg daily for a 5-year history of atrial fibrillation with past evidence of a single embolic event. Other medical problems include hypertension and diabetes, controlled with an angiotensin-converting enzyme (ACE) inhibitor and diet. She also takes a baby aspirin each day.
Examination reveals a healthy black female with no complaints. Positive findings on examination include an irregularly irregular heart rhythm and a faint diastolic murmur. Vital signs: BP - 155/80 mm Hg, pulse - 75 bpm, resp - 16/min, T - 37°C.
Platelet count = 210,000/μL
PT = 25.1 seconds (<14 seconds)
INR = 2.4 (0.8–1.3)
PTT = 29 seconds (22–35 seconds) Question
Successful management of the patient with a thrombotic disorder requires evaluation of risk factors for thrombosis, a careful assessment of the site and extent of the thrombus, and a skilled choice and application of a number of anticoagulants. Diagnostic evaluation of the thromboembolic patient is discussed in Chapter 36. Treatment of the patient with a thrombus involves both dissolution of the clot and prevention of recurrence. Specific therapy will be dictated by the type of vessel involved, whether arterial or venous, and the clinical setting (Table 37-1). As a general rule, thrombotic disorders of arterial vessels are best managed using a combination of thrombolytic agents to rapidly dissolve the obstructing clot and anti-platelet drugs to prevent recurrence. In contrast, venous thromboembolism responds best to drugs such as heparin, fondaparinux, and warfarin that inhibit the function and formation of coagulation factors.
TABLE 37-1Recommended therapy of thrombotic disordersa |Favorite Table|Download (.pdf) TABLE 37-1 Recommended therapy of thrombotic disordersa
|Condition ||Therapy |
|Coronary artery disease |
|Stable angina/infarct prevention ||Aspirin |
|Unstable angina ||Aspirin ± clopidogrel for outpatients; aspirin plus LMWH or UFH for hospitalized patients |
|Acute myocardial infarction (<6 hours old) ||Thrombolysis using intravenous streptokinase or t-PA plus full-dose heparin and aspirin |
|Anterior transmural infarcts (risk of mural thrombosis) ||Full-dose heparin followed by warfarin therapy for 2–3 months |
|Reinfarction prevention ||Long-term aspirin ± clopidogrel |
|Bypass graft patency ||Aspirin/clopidogrel |
|Cerebral artery disease |
|Transient ischemic attacks ||Aspirin or clopidogrel or both |
|Recurring TIAs/evolving thrombotic stroke ||LMWH or UFH followed by warfarin or aspirin alone (treatment debatable) |
|Completed thrombotic stroke ||Aspirin or clopidogrel or both |
|Cerebral embolism |
|Without hemorrhage on CT scan ||LMWH or UFH followed by long-term warfarin therapy |
|With hemorrhage on CT scan ||Postpone anticoagulation for 2 weeks |
|Valvular heart disease |
|Valvular disease (especially mitral stenosis) with atrial fibrillation or history of embolism; recurrent episodes of paroxysmal atrial fibrillation ||Long-term warfarin therapy |
|Atrial fibrillation cardioversion ||Warfarin therapy for 2–3 weeks prior to and 4 weeks after cardioversion |
|Bioprosthetic mitral valves ||Long-term moderate-dose ...|
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