Lecture note on venous thrombosis prepared with reference of surgical text books

1. Bailey & Love-Short practice of Surgery.25th
Venous Thrombosis
“Formation of a semi-solid coagulum within flowing blood in the venous system.”
Could be any where: cavernous, azygous, mesenteric, iliac, LL deep vein
Complication
Immediate risk of pulmonary embolus→ sudden death.
post-thrombotic limb→ venous ulceration.
Aetiology
1. changes in the vessel wall (endothelial damage);
2. stasis, which is diminished blood flow through the veins;
3. coagulability of blood (thrombophilia).
Risk factors for VT
Patient factors
1. Age
2. Obesity
3. Varicose veins
4. Immobility
5. Pregnancy
6. Puerperium
7. High-dose oestrogen therapy
8. Previous DVT or PE
9. Thrombophilia
Disease or surgical procedure
1. Trauma or surgery, especially of
pelvis, hip and lower limb
2. Malignancy, especially pelvic, and
abdominal metastatic
3. Heart failure
4. Recent MI
5. Paralysis of lower limb(s)
6. Infection
7. IBD
8. Nephrotic syndrome
9. Polycythaemia
10. Paraproteinaemia
11. PNH antibody or lupus anticoagulant
12. Behçet’s disease
13. Homocystinaemia
Abnormalities of thrombosis and fibrinolysis that lead to an ↑ risk of venous thrombosis
Congenital
1. Deficiency of anti-thrombin III, protein C or protein S
2. Antiphospholipid antibody or lupus anticoagulant
3. Factor V Leiden gene defect or activated protein C resistance
4. Dysfibrinogenaemias
Acquired
1. Antiphospholipid antibody or lupus anticoagulant
‘e-thrombosis’:blood clots occurring in people sitting at their computers for long periods of time.

2. Bailey & Love-Short practice of Surgery.25th
A thrombus often develops in the soleal veins of the calf.
Thrombus→ totally occlude perfusion to all or part of one or both lungs (PE).
Acute right heart obstruction →sudden collapse and death.
Lung infarction is rare as the lung has a dual blood supply (bronchial and pulmonary arteries).
Moderately sized emboli can cause pyramidal shaped infarcts.
Diagnosis
1. Pain and swelling, especially in the calf of one lower limb.
2. Mild pitting oedema of the ankle,
3. Dilated surface veins,
4. Stiff calf
5. Tenderness over the course of the deep veins
6. Low-grade pyrexia: especially in repeated PE.
B/L DVT - DD
Causes of systemic oedema
hypoproteinaemia
renal failure
heart failure.
Asymptomatic + signs of a PE
e.g. pleuritic chest pain,
haemoptysis and
SOB
Other
1. cellulitic
2. white or cyanosed: phlegmasia alba dolens & phlegmasia cerulia dolens
3. If venous gangrene → they often have an underlying neoplasm.
Homans’ sign – resistance (not pain) of the calf muscles to forcible dorsiflexion →outdated
If having PE causing right heart strain
i. Signs of cyanosis
ii. Dyspnoea
iii. Raised neck veins
iv. A fixed split S2
v. Pleural rub
Investigation
D-dimer→ if ↑, a duplex USS of the deep veins should be performed.
Presence of a thrombosis
Filling defects in flow
lack of compressibility
1. Ventilation–perfusion scanning→ mismatched defects
2. CT scanning of the pulmonary arteries→ filling defects in the pulmonary arteries
Rarely required
Ascending venography
Pulmonary angiography
DD-DVT
1. Ruptured Baker’s cyst
2. Calf muscle haematoma
3. Ruptured plantaris muscle

3. Bailey & Love-Short practice of Surgery.25th
4. Thrombosed popliteal aneurysm
5. Arterial ischaemia.
DD-PE
1. MI
2. pleurisy
3. Pneumonia.
Prophylaxis
Grade as low,moderate or high risk.
Low-risk
o Young
o Minor illnesses
o Operations lasting 30 min or less
Moderate
o Age >40
o Debilitating illness
o Major surgery
Highrisk
o Age >40
o Serious medical conditions: stroke/MI
o Major surgery with an additional risk factor: H/O VTE or known malignant disease.
Mechanical
1. Graduated elastic compression stockings
2. External pneumatic compression
Pharmacological
(More effective than mechanical methods at reducing the risk of thrombosis)
LMWH S/C –dose-wt
i. Does not require monitoring
ii. ↓Risk of heparin-induced thrombocytopenia
iii. Can be given once a day
iv. Lower risk of bleeding complications.
UFH, warfarin: rarely
Treatment
S/C LWMH
Warfarin (D1-10mg, D2-10mg, D3-5mg, D3-PT for maitainance dose guidance)
Thrombolysis: tPA
Stent grafting: ‘iliac vein compression syndrome’
Venous thrombectomy +AV fistula: iliac veins
Rx-PE
Anticoagulation
Observation
Severe right heart strain+SOB→ fibrinolytic treatment.
Rarely-cardiac arrest →surgical pulmonary embolectomy.
Prophylaxis against PE
I
o
Filters (vena cava filter-Greenfield filter)
1. High risk of embolism
2. When anticoagulants are contraindicated
3. Pts who continue to have PE despite adequate anticoagulation.

4. Bailey & Love-Short practice of Surgery.25th
Superficial thrombophlebitis
Common causes
i. External trauma (especially to varicose veins),
ii. Venepunctures
iii. Infusions of hyperosmolar solutions & drugs
iv. The presence of an iv cannula for > 24–48 hrs
v. coagulation disorders
a. polycythaemia,
b. thrombocytosis
c. sickle cell disease
Some systemic diseases
Buerger’s disease
Malignancy, esp. pancreas
↓
Flitting thrombophlebitis
(thrombophlebitis migrans)
↓
affecting different veins at different times.
C/F
Vein→ solid & tender
Skin→ may be attached to the vein
Erythematous → brown.
A linear segment of vein of variable length can be easily palpated once the Inflammation has died down.
Ix
FBC
Coagulation screen
Duplex scan
Malignancy: endoscopy, imaging: abdominal CT scan.
Rx
Mostly:NSAIDs and the condition resolves spontaneously.
Incision or excision of infected thrombi:rare
Ligation to prevent propagation into the deep veins is almost never required.
Anticoagulation: associated dvt or thrombophilias