Vascular Surgery JC001: Varicose Veins: Diseases Of The Veins And Lymphatics, Venous Thrombosis Flashcards
Anatomy of venous system
2 systems of Superficial veins:
1. Long saphenous system: anterior to medial malleolus —> medial to leg —> go into Deep vein via Saphenous opening / Saphenofemoral junction (2cm lateral + below pubic tubercle)
2. Small saphenous system: lateral side of foot —> back of calf —> Popliteal vein (via Popliteal fossa)
Perforating / Communicating vein system:
- located at constant position in body
—> Lower, Middle, Upper calf perforators (5 cm apart)
—> Knee perforators
—> Mid-thigh perforators
Divided into (被deep fascia隔開):
1. Deep veins
- travel with arteries with same name
- drain deeper structures (e.g. muscles, bones, joints)
- found deep to muscles
- usually paired when accompanying medium sized arteries (Venae comitantes)
- valves present
- Superficial veins
- run in superficial fascia (superficial to muscle)
- drain SC tissue
- externally visible
- communicate with deep veins at regular intervals by Perforating / Communicating veins (pierce deep fascia)
- valves present to direct blood from superficial to deep vein —> systemic veins
- Clinically important: Venipuncture, Transfusion
- Prone to Varicosities (lower limb)
Lower limb venous blood flow:
Superficial veins
—> Deep veins
—> Femoral vein
—> External iliac vein
—> Common iliac vein
—> IVC
—> RA
- Dorsal venous arch (foot dorsum)
- Great saphenous vein (medial)
- from medial arch (2/3 cm anterior to medial malleolus: accessible for venous cutdowns) —> medial leg —> behind knee —> medial thigh —> Saphenous opening (in deep fascia of thigh, 3/4 cm lateral and below pubic tubercle) —> Femoral vein
- used as graft in coronary bypass surgery - Small saphenous vein (back)
- from lateral arch —> back of leg —> Popliteal vein at popliteal fossa
Blood flow:
Dorsal venous network (plantar arch)
1. Great saphenous vein —(Saphenous opening)—> Femoral vein
2. Small saphenous vein —> Popliteal vein —> Femoral vein
Venous system diseases
- Incompetence of valves —> Chronic venous insufficiency (CVI)
- Obstruction
- clot formation (i.e. VT)
Chronic Venous Insufficiency (CVI)
Severity ranging from Varicose —> Leg ulcers
Clinical features (記E—>P—>E—>U):
- Mild: Varicose veins
- Moderate: Edema, Eczema, Pigmentation (may not have varicose veins)
- Severe: Leg ulceration (Venous reflux —> Skin changes, chronic swelling —> Ulcers)
Pathophysiology:
- Incompetent valves (leaking) (Superficial / Deep / Perforators)
—> Backflow of blood (downwards / from deep to superficial)
—> ↑ Pressure in superficial system (not accustomed to high pressure)
—> Lengthen + Dilatation (visible under the skin)
Symptoms of Varicose veins:
- Disfigurement
- Swelling + Ache (as if standing for long time)
Complications:
- Bleeding
- Thrombosis (i.e. SVT) (∵ slow flow of blood)
Etiology of Incompetent valves:
1. Primary
- Congenital weakness in CT
- Posture (Prolonged standing)
—> usually at major valves esp. Saphenofemoral junction
- Secondary
- Post-thrombotic (secondary to DVT)
—> Clots dissolved and reabsorbed by body
—> Valves damaged by thrombosis + reabsorption process
—> Venous reflux to superficial veins
Venous pressure
Weight of column of blood from heart to level of foot:
Normal: 120 cmH2O
- Exercise with Normal leg: 40 cmH2O (∵ venous blood pumped by muscles towards heart)
- Exercise with Superficial reflux: 80 cmH2O
- Exercise with Post-phlebitic leg: 110 cmH2O
—> Lower limb subjected to continuously high level of venous pressure
—> Ambulatory Venous Hypertension (main culprit)
***Pathology of Ambulatory Venous Hypertension
Venous reflux
—> Venous hypertension
—> Capillary hypertension
—> Diffusion process + Leukocyte-damaging process
—> Lymphatics overloaded + ↓ Reabsorption of tissue fluid at Venous end
—> Fluid accumulation
—> Edema
During diffusion process:
1. RBC
—> goes out and die in interstitium (but cannot reabsorbed by veins)
—> Iron-containing Hb stays as Haemosiderin
—> Brown pigmentation of legs
- Plasma proteins + Fibrin
—> chronic inflammatory reaction in tissues
—> deposit of fibrin / fibrinogen around capillary (form cuffs)
—> prevent active effusion of nutrients to supply skin
—> Thickening of skin (unhealthy skin)
—> Dark, Itchy skin
—> Breakdown of skin
—> Ulcer
CEAP Classification of CVI (x rmb)
C: Clinical
E: Etiology (Congenital, Primary, Secondary)
A: Anatomy (Superficial, Perforator, Deep)
P: Pathology (Reflux, Obstruction, Both)
C1-6 (記: C1-3都係varicose veins)
C1: Telangiectasia / Reticular veins
C2: Varicose veins
C3: Edema
C4:
- a: Pigmentation / Eczema
- b: Lipodermatosclerosis (proximal leg swelling from venous obstruction, distal leg shrinks from chronic ulceration + fat necrosis)
C5: Healed ulcer
C6: Active ulcer
Present during PE:
- This is a patient with CVI
- according to CEAP classification, Clinical stage 3
- with etiology from Primary reflux
- Affecting Saphenofemoral junction
- causing Reflux in superficial veins
- as a result of Chronic Venous Hypertension
P/E of Varicose veins
- Tourniquet examination / Trendelenburg test
- Only doable in gross varicose veins
- Lie patient down —> observe + describe venous changes and course —> elevate leg —> empty the veins against gravity —> tie tourniquet below SFJ —> stand up —> look + palpate veins
—> if veins still visible —> indicate valve incompetence in lower level
—> if veins not visible —> indicate SFJ incompetence
- 係倒流個點下面扎住 —> 靜脈消失
- Examine axial + perforators - USG Duplex
- Axial reflux (i.e. Great saphenous veins)
- Perforator location
—> showing bidirectional flow of blood / from deep —> superficial
—> indicate reflux
***Management of Varicose veins
Conservative treatment (Principle: ↓ Venous Pressure)
1. Elevation
2. Postural adjustments (avoid prolonged standing)
3. Graduated compression stockings (compression force ↑ downwards)
Surgery (Principle: Ligate incompetent perforators (biggest perforator: SFJ) + Remove diseased veins)
1. High/Flush Ligation of SFJ / Ligation of all tributaries
2. Stripping of incompetent lesser SV / Stab avulsion of branches (~ digging out earthworms)
3. Interruption of perforating veins
Minimally invasive surgery:
1. Thermal ablation
- Laser (Endovenous Laser Treatment EVLT)
- Radiofrequency (Venefit)
—> via Catheter into GSV under USG guidance
—> leave 2cm from SFJ
—> inject fluid as tumescence into leg to separate skin + compress veins
—> protect skin from burn due to heat
-
Mechanical ablation
- Chemical ablation + Glue (Sclerosants to obliterate lumen) - Reticular branches: Injection of Sclerosants / Radiofrequency (i.e. within SC layer) (causing fibrosis of veins)
- Sclerosants: Detergents / Surfactants
- does not treat primary culprit (i.e. Perforator incompetence) - External laser for Telangiectasia
Severe CVI
Valvular insufficiency in Deep veins as well
Other names:
- Post-thrombotic / Post-phlebitic syndrome
- Chronic venous stasis
- Chronic venous hypertension
Clinical features:
- Pigmentation
- Edema
- Eczema
- Ulceration (not very painful)
***DDx of Leg ulcers
- Arterial
- signs of Arterial insufficiency (e.g. absent pulses, skin changes, gangrene toes)
- painful
- pressure areas
- never heals (unless revascularisation) - Venous
- signs of CVI (pigmentation, thickening of skin, edema)
- good pulse
- less painful (∵ no ischaemia)
- site (lower part around medial malleolus) - Neurogenic
- painless
- neuropathy (e.g. DM, leprosy) - Malignant
- SCC
- irregular, raised edges
- Marjolin’s ulcer (occurs on chronic existing venous ulcer)
- LN in groins
- biopsy (at edge where it’s more active, not in middle: necrotic already) - Infection
- chronic osteomyelitis
- syphilis
- TB - Trauma
Management of Severe CVI
- Posture: Elevation of leg / Bed rest
- ↓ Venous Pressure (to allow ulcer to heal) -
Dress ulcers
- Bandage
- Treating infection -
Skin grafts
- Topical ulcer treatment
- promote healing - Superficial venous surgery
- Superficial reflux
- ligating superficial veins / perforators —> prevent superficial reflux —> prevent overloading of deep veins —> ↓ Venous pressure in deep veins -
Deep vein reconstruction
- Deep reflux (rarely done)
- Replace defective deep vein with superficial vein with good valve - Compression therapy
- Multi-layer compression
Deep Vein Thrombosis
Virchow’s Triad (3 Factors contributing to Thrombosis):
- Stasis
- Trauma
- Hyper-coagulability
Pathophysiology:
- Blood clots —> ↓ Venous return —> Swelling in leg
Clinical features:
1. Silent (Phlebothrombosis)
-
Thrombophlebitis
- Swelling, Pain, Warmth, Redness (紅腫痛熱)
- Homan’s sign (Dorsiflex ankle —> Pain in calf ∵ stretches thrombus in calf veins) -
Venous gangrene
- swelling —> compression on arterial / capillary flow —> gangrene
Usually occurs on left leg
- ∵ Right common iliac artery passes in front of Left common iliac vein
—> compression on Left common iliac vein
—> May–Thurner syndrome (MTS)
(aka Iliac vein compression syndrome: a condition in which compression of the common venous outflow tract of the left lower extremity may cause discomfort, swelling, pain or clots (deep venous thrombosis) in the iliofemoral veins)
Investigations of DVT
-
Venous Duplex
- Less compressible vein by probe
- Lose phasic variation of bloodflow on USG
- Less good augmentation of flow by compression of vein -
Venogram
- contrast to show filling defect
***Complications of DVT
-
Pulmonary embolism
- block pulmonary artery
- usually only occur in proximal DVT (ileofemoral DVT) -
Chronic Venous Insufficiency
- re-cannulation / reabsorption of clot —> damaged valves —> superficial reflux —> high venous pressure —> symptoms of Venous hypertension -
Chronic Venous Obstruction
—> higher venous pressure —> symptoms of Venous hypertension
***Treatment of DVT
Goal:
1. Prevent pulmonary embolism
2. Relieve acute symptoms (pain, swelling)
3. Prevent recurrent DVT
4. Prevent post-thrombotic sequelae
Conservative treatment:
1. Anticoagulant
- Heparin (5 days)
—> Oral anticoagulants + SC heparin / LMWH (3 months)
2. Elevation of leg + Bandages (reduce pressure / swelling)
3. Bed rest (relieve inflammation)
Aggressive therapy:
1. Catheter-directed thrombolysis
- infuse thrombolytics via catheter puncturing deep veins
- aspirate blood clots
-
Venous thrombectomy
- mechanical thrombectomy + stent
