What are the symptoms and treatment options for a patient with a blood clot, particularly those with a history of deep vein thrombosis (DVT) or pulmonary embolism (PE)?

Symptoms of Blood Clots

Blood clots in the legs (DVT) present with redness, tenderness, swelling, pitting edema, and appearance of collateral superficial veins, while blood clots in the lungs (PE) manifest as dyspnea, chest pain, cough, tachycardia, cyanosis, dizziness, fainting, and excessive sweating. 1

Clinical Manifestations of Deep Vein Thrombosis (DVT)

• Leg symptoms include: redness, tenderness, swelling, pitting edema, and visible collateral superficial veins 1
• These symptoms are not specific and cannot reliably confirm DVT based on clinical presentation alone 1
• Imaging is necessary to confirm the diagnosis in all suspected cases 1

Clinical Manifestations of Pulmonary Embolism (PE)

• Respiratory symptoms: dyspnea (shortness of breath), chest pain, and cough 1
• Cardiovascular signs: tachycardia (rapid heart rate) and cyanosis (bluish discoloration) 1
• Systemic symptoms: dizziness, fainting (syncope), and excessive sweating 1
• PE is the third most common cause of cardiovascular death after heart attack and stroke 2

Diagnostic Approach

For Cancer Patients

• Proceed directly to imaging without using clinical prediction rules or D-dimer testing 1
• Use compression ultrasonography (CUS) for suspected DVT 1
• Use computed tomography pulmonary angiography (CTPA) for suspected PE 1
• Clinical decision rules and D-dimer testing perform poorly in cancer patients 1

For Non-Cancer Patients

• Clinical probability assessment combined with D-dimer testing can safely exclude VTE in low-probability patients with negative D-dimer 3, 4
• Compression ultrasound confirms DVT 3
• Chest CT confirms PE 3

Treatment Options

First-Line Anticoagulation

Direct oral anticoagulants (DOACs) are preferred over vitamin K antagonists (warfarin) for most patients with DVT or PE due to superior safety profile and ease of use 1, 5

• DOACs include apixaban, rivaroxaban, edoxaban, and dabigatran 5
• No single DOAC is superior to another; choice depends on renal function, drug interactions, and dosing convenience 1
• Apixaban dosing: 10 mg twice daily for 7 days, then 5 mg twice daily (must be taken with food) 5
• Rivaroxaban: requires initial higher dose followed by maintenance dosing 5
• Edoxaban: requires initial parenteral anticoagulation before starting 5

Alternative Anticoagulation Options

• For cancer patients: Low-molecular-weight heparin (LMWH) is preferred over DOACs or warfarin 1, 5
• For patients with renal insufficiency (creatinine clearance <30 mL/min): DOACs may not be appropriate; consider dose adjustment or alternative agents 5
• For antiphospholipid syndrome: DOACs are not appropriate; use warfarin 1
• Warfarin target INR: 2.5 (range 2.0-3.0) for all treatment durations 6

Duration of Anticoagulation Therapy

• Provoked DVT/PE (surgery or transient risk factor): 3 months of anticoagulation 5, 6
• First unprovoked DVT/PE with low-moderate bleeding risk: Extended therapy (no scheduled stop date) 5
• Recurrent VTE: Indefinite anticoagulation 5
• Cancer-associated thrombosis: Continue LMWH for at least 3-6 months and as long as cancer is active 5

Thrombolytic Therapy

For PE with hemodynamic compromise (systolic BP <90 mm Hg): Thrombolytic therapy followed by anticoagulation is recommended despite low certainty evidence due to high mortality risk 1

• For PE without hemodynamic compromise: Anticoagulation alone is recommended; avoid routine thrombolysis 1
• For submassive PE (right ventricular dysfunction without hypotension): Anticoagulation alone is preferred, but thrombolysis may be considered in younger patients at low bleeding risk 1
• For most proximal DVT: Anticoagulation alone is preferred over thrombolysis 1, 5
• For limb-threatening DVT (phlegmasia cerulea dolens): Thrombolysis is reasonable to consider 1
• Catheter-directed thrombolysis is preferred over systemic thrombolysis when thrombolysis is indicated for extensive DVT 1

Common Pitfalls and Caveats

• Do not rely on symptoms alone to diagnose or exclude VTE; imaging is mandatory 1
• DOACs have significant drug interactions with CYP3A4 enzyme and P-glycoprotein inhibitors/inducers 1, 5
• Monitor renal function regularly when using DOACs, as dosing may require adjustment 5
• Avoid DOACs in moderate-severe liver disease 5
• If breakthrough VTE occurs on therapeutic warfarin: Switch to LMWH rather than a DOAC 5
• Inferior vena cava filters are not recommended in addition to anticoagulation for routine DVT treatment 5
• Compression stockings are not routinely recommended to prevent post-thrombotic syndrome 5