Chronic Venous Insufficiency and Deep Vein Thrombosis

Clinical Orientation

A 55-year-old woman on oral contraceptives just returned from a long-haul flight. Her left calf is swollen, warm, and tender. Homan's sign is unreliable and should not be used to rule out DVT. A venous duplex confirms acute DVT in the left popliteal vein. This chapter answers: What mechanism links CVI and DVT to bedside findings, tests, red flags, and nursing priorities?

Cross-reference: Book 3 covers the full pulmonary embolism pathophysiology. Book 9 covers coagulation disorders in depth.

What Is Normal?

Venous return: Veins are low-pressure, thin-walled, highly compliant vessels. Venous return to the heart depends on: skeletal muscle pump (calf muscles compress veins during walking, valves ensure one-way flow), respiratory pump (inspiration decreases intrathoracic pressure, drawing blood toward the heart), and venous tone. Venous valves prevent retrograde flow. When valves fail → venous hypertension → CVI.

Virchow's triad: Three factors that promote thrombosis:

1. Venous stasis: Immobility, bed rest, paralysis, prolonged sitting (travel), heart failure, venous obstruction.
2. Endothelial injury: Surgery, trauma, central lines, previous DVT, inflammation.
3. Hypercoagulability: Malignancy, pregnancy/postpartum, oral contraceptives/hormone therapy, inherited thrombophilias (Factor V Leiden, prothrombin mutation, protein C/S deficiency), inflammatory states.

What Goes Wrong?

DVT: Thrombus forms in deep veins (most commonly lower extremity). The thrombus may: resolve (fibrinolysis), organize (become incorporated into vein wall), extend (grow proximally), or embolize (break off → travel to lungs → PE). Proximal DVTs (popliteal, femoral, iliac) are much more likely to embolize than distal (calf) DVTs.

CVI: Chronic venous hypertension from valve incompetence and/or venous obstruction. Venous pressure rises → capillary leakage → edema, hemosiderin deposition (brown discoloration from RBC breakdown), stasis dermatitis, lipodermatosclerosis (fibrosis of subcutaneous tissue), venous stasis ulcers (typically medial malleolus — shallow, irregular, with drainage).

What the Nurse May See

DVT: Unilateral leg swelling, warmth, erythema, tenderness. Palpable cord. Dilated superficial veins. Homan's sign (calf pain with dorsiflexion) is unreliable and potentially dangerous (may dislodge thrombus). Many DVTs are asymptomatic.

PE warning signs (from DVT): Sudden dyspnea, pleuritic chest pain, tachypnea, tachycardia, hemoptysis, syncope. See Book 3 for full PE discussion.

CVI: Chronic edema (worse at end of day, improves with elevation). Brown discoloration (hemosiderin). Stasis dermatitis (itchy, scaly, inflamed skin). Venous ulcers (shallow, weeping, irregular borders; usually medial malleolus). Compare with arterial ulcers (punched-out, deep, dry, painful; toes, pressure points).

Tests and Monitoring

• D-dimer: Fibrin degradation product. High sensitivity, low specificity. Elevated in DVT, PE, but also in pregnancy, recent surgery, malignancy, inflammation, age. A NEGATIVE D-dimer effectively excludes DVT/PE in low-risk patients. A POSITIVE D-dimer requires further imaging.
• Venous duplex ultrasound: Gold standard for DVT diagnosis. Noncompressible vein = DVT.
• Wells criteria: Clinical prediction rules for DVT and PE pretest probability.

Nursing Priorities

For DVT:

1. Anticoagulation: LMWH (enoxaparin) or fondaparinux as initial therapy. Warfarin (bridged with LMWH until INR therapeutic) or DOAC (apixaban, rivaroxaban — no bridging needed). Monitor for bleeding.
2. Elevation and compression: Elevate affected leg. Compression stockings once acute phase resolved (reduce post-thrombotic syndrome).
3. Monitor for PE: Any sudden dyspnea, chest pain, tachycardia, hypoxia → urgent evaluation.
4. Never massage the affected leg (may dislodge thrombus).

For CVI:

1. Compression therapy: Graduated compression stockings (higher pressure at ankle, decreasing proximally). Apply in morning before edema develops.
2. Leg elevation: Above heart level when sitting/sleeping.
3. Wound care for venous ulcers: Moist wound healing, compression over dressing, infection monitoring.
4. Exercise: Walking activates calf muscle pump.

Red Flags

Patient Teaching

• "The blood clot in your leg can break off and travel to your lungs — that's why we give blood thinners. Take them exactly as prescribed. Report any unusual bleeding — nosebleeds, bleeding gums, blood in urine or stool, easy bruising. Call 911 for sudden shortness of breath or chest pain."
• CVI: "Elevate your legs above your heart when resting. Wear your compression stockings daily. Walk regularly. Keep your skin moisturized and inspect daily."