5.3 Peripheral Vascular Disease, Venous Thromboembolism, and Anticoagulation Safety
Key Takeaways
- Arterial ulcers are punched-out, pale, dry, and intensely painful on the toes or lateral malleolus, while venous ulcers are shallow, irregular, wet, and relatively less painful over the medial malleolus with surrounding haemosiderin staining.
- Compression therapy heals venous ulcers but can be limb-threatening in arterial disease; an ankle-brachial index below 0.8 must be excluded before compression is applied.
- Elevate the limb in venous insufficiency and keep it dependent in arterial insufficiency; applying the wrong rule worsens the underlying perfusion problem.
- Protamine sulfate reverses unfractionated heparin, vitamin K reverses warfarin, idarucizumab reverses dabigatran, and andexanet alfa reverses apixaban and rivaroxaban.
- A falling platelet count between days 5 and 10 of heparin therapy, with new thrombosis rather than bleeding, indicates heparin-induced thrombocytopenia; stop all heparin, including line flushes, and switch to a non-heparin anticoagulant.
5.3 Peripheral Vascular Disease, Venous Thromboembolism, and Anticoagulation Safety
Vascular items reward one discipline above all: decide first whether the problem is arterial inflow or venous outflow, because almost every nursing action reverses between the two. Elevate a venous limb, lower an arterial one. Compress a venous ulcer, never compress an ischaemic one. Warm a vasospastic limb, never apply direct heat to a neuropathic one.
Arterial vs. Venous Insufficiency
| Feature | Peripheral arterial disease | Chronic venous insufficiency |
|---|---|---|
| Pain | Intermittent claudication; rest pain relieved by dangling the leg | Dull ache, heaviness, relieved by elevation |
| Pulses | Diminished or absent | Present |
| Skin | Thin, shiny, hairless, cool, pale on elevation, dusky red when dependent | Thickened, brown haemosiderin staining, oedema, eczema |
| Ulcer site | Toes, heel, lateral malleolus, pressure points | Medial malleolus |
| Ulcer appearance | Punched-out, deep, pale base, minimal exudate, very painful | Shallow, irregular edges, granulating, heavy exudate |
| Oedema | Minimal | Marked, worse at the end of the day |
| Positioning | Dependent — keep the limb at or below heart level | Elevated above heart level |
| Compression | Contraindicated unless arterial disease is excluded | Mainstay of therapy |
Ankle-brachial index (ABI) is the objective arbiter: the highest ankle systolic pressure divided by the highest brachial systolic pressure. Normal is 1.0 to 1.4; 0.9 to 1.0 borderline; below 0.9 confirms arterial disease; below 0.5 signals critical limb ischaemia; values above 1.4 are falsely elevated by calcified incompressible vessels, which is common in long-standing diabetes. Do not apply compression bandaging or stockings until arterial disease has been excluded — compressing a limb with an ABI below about 0.8 can precipitate tissue necrosis.
Acute limb ischaemia presents with the six Ps: pain, pallor, pulselessness, paraesthesia, paralysis, and poikilothermia (coldness). Paraesthesia and paralysis are the late, limb-threatening signs. This is a vascular emergency: keep the limb dependent and at room temperature, do not elevate, do not apply heat or cold, protect it from pressure, withhold oral intake in anticipation of surgery, and escalate immediately.
Foot care teaching in arterial disease and diabetes is high-yield: inspect the feet daily including between the toes using a mirror, wash in lukewarm water tested with the forearm or a thermometer, dry thoroughly between the toes, apply lotion to the foot but not between the toes, cut nails straight across, never use over-the-counter corn removers or chemical callus treatments, never walk barefoot, never apply a hot water bottle or heating pad, and always inspect the inside of shoes before putting them on.
Venous Thromboembolism
Virchow's triad explains every risk factor: venous stasis (immobility, long flights, heart failure), endothelial injury (surgery, trauma, central lines), and hypercoagulability (malignancy, pregnancy, oestrogen therapy, inherited thrombophilia, sepsis, dehydration).
Deep vein thrombosis typically presents with unilateral calf or thigh pain, swelling, warmth, and erythema, with a measurable difference in limb circumference. Classical signs such as Homans' sign are unreliable and should not be used to rule DVT in or out. Diagnosis rests on compression ultrasonography, with D-dimer useful mainly to exclude DVT in low-probability patients.
Nursing care of an established DVT: anticoagulation as prescribed, early mobilisation once therapeutic anticoagulation is established (prolonged bed rest is no longer recommended), analgesia, graduated compression where arterial disease is excluded, and measurement of limb circumference at a marked fixed point for comparability. Never massage the affected limb.
Pulmonary embolism is the feared consequence: sudden dyspnoea, pleuritic chest pain, tachypnoea, tachycardia, apprehension, and sometimes haemoptysis or syncope. Immediate nursing actions are to sit the patient upright, give high-flow oxygen, obtain vital signs and intravenous access, stay with the patient, and escalate urgently.
Prophylaxis is a nursing responsibility and a recurrent exam theme: early ambulation, ankle-pump and leg exercises, adequate hydration, intermittent pneumatic compression devices, graduated compression stockings correctly sized and removed for skin inspection at least daily, and prescribed pharmacological prophylaxis such as low-molecular-weight heparin.
Aortic Aneurysm
An abdominal aortic aneurysm is often asymptomatic and found incidentally as a pulsatile mass near the umbilicus with a bruit. Do not palpate deeply or repeatedly once an aneurysm is suspected. Sudden severe tearing abdominal or back pain with hypotension suggests rupture or dissection — a surgical emergency. A thoracic dissection classically produces tearing chest pain radiating to the back with a blood pressure differential between the arms. Post-repair nursing focuses on blood pressure control within a prescribed narrow range, hourly urine output as a marker of renal perfusion, distal pulse and neurovascular checks, and vigilance for graft occlusion and spinal cord ischaemia.
Anticoagulation: Monitoring, Reversal, and Teaching
| Agent | Monitoring | Reversal agent | Key nursing point |
|---|---|---|---|
| Warfarin | INR | Vitamin K (phytonadione); fresh frozen plasma or PCC if bleeding | Consistent vitamin K intake, not avoidance; many drug interactions |
| Unfractionated heparin | aPTT (1.5–2.5 × control) | Protamine sulfate | Monitor platelets for HIT; infusion via pump only |
| Low-molecular-weight heparin | Usually none; anti-Xa if indicated | Protamine (partial only) | Do not expel the air bubble; do not aspirate or massage |
| Dabigatran | None routine | Idarucizumab | Keep in original container; moisture-sensitive |
| Apixaban, rivaroxaban | None routine | Andexanet alfa | Rivaroxaban higher doses taken with food |
| Aspirin, clopidogrel | None routine | Platelet transfusion if severe bleeding | Hold before surgery per surgical instruction |
Warfarin teaching is a perennial exam item. The message is consistency, not avoidance: the patient should keep vitamin K intake steady rather than eliminating green vegetables, because erratic intake is what destabilises the INR. Patients should use a soft toothbrush and an electric razor, avoid contact sports, report black tarry stools, pink or red urine, unusual bruising, or a severe headache, carry an anticoagulation alert card, and check with the pharmacist before any new medication or herbal product — including over-the-counter non-steroidal anti-inflammatories.
Heparin-induced thrombocytopenia (HIT) is the counterintuitive complication candidates most often miss. Between days 5 and 10 of heparin exposure, an immune reaction destroys platelets, yet the clinical problem is new thrombosis, not bleeding. A platelet fall of 50% or more from baseline in that window demands that all heparin be stopped, including catheter flushes and heparin-bonded lines, and a non-heparin anticoagulant such as argatroban or fondaparinux substituted. Platelet transfusion is avoided because it feeds the thrombotic process.
A community nurse is preparing to apply graduated compression bandaging to a patient with a shallow, heavily exuding ulcer over the medial malleolus. Before applying compression, which assessment finding would make the intervention unsafe?
A patient receiving a continuous unfractionated heparin infusion for pulmonary embolism has a platelet count that has fallen from 245,000/mm³ on admission to 96,000/mm³ on day 7. The patient has no bleeding but reports new pain and swelling in the opposite calf. What is the priority nursing action?
A nurse is reinforcing discharge teaching for a patient newly prescribed warfarin after a mechanical mitral valve replacement. Which statement by the patient indicates that teaching has been effective?