Upper Extremity Ischemia
Upper extremity ischemia มีความหลากหลายของสาเหตุและ
presentation มากกว่า lower extremity ischemia โดยแบ่งได้เป็น:
- large
vessel disease (proximal to wrist)
- small
vessel disease (distal to wrist)
สาเหตุใน upper extremity ไม่ได้เกิดจาก
atherosclerosis เป็นหลักเสมอไป แต่ embolism,
vasculitis, vasospasm, thoracic outlet syndrome และ autoimmune
disease มีบทบาทสำคัญ
Definitions
Acute upper extremity ischemia
- onset
<2 weeks
- usually
thromboembolic
- limb-threatening
emergency
Chronic upper extremity ischemia
- progressive
arterial narrowing
- often
collateral compensated
Key anatomy
Arterial supply
Subclavian artery
→ Axillary artery
→ Brachial artery
→ Radial/Ulnar arteries
→ Palmar arches
Important collateral circulation
Upper extremity collateral circulation ดีมากกว่า
lower extremity
จึงทำให้:
- severe
ischemia พบได้น้อยกว่า
- amputation
จาก vascular disease พบน้อย
Dual blood supply ของ hand:
- radial
artery
- ulnar
artery
complete palmar arch พบได้ถึง ~90%
Major causes
1. Arterial embolism (most common acute cause)
ประมาณ 61% ของ acute
upper limb ischemia
Common sources
- atrial
fibrillation
- valvular
disease
- LV
thrombus
- endocarditis
- cardiac
myxoma
2. Atherosclerotic disease
พบได้น้อยกว่า lower extremity
Sites:
- subclavian
- axillary
- brachial
artery
3. Trauma
Penetrating
- knife
- gunshot
Blunt
- shoulder
traction injury
- humeral
fracture/dislocation
- elbow
dislocation
4. Thoracic outlet syndrome (arterial TOS)
มักเกิดจาก cervical rib
Mechanism:
- subclavian
artery compression
- poststenotic
aneurysm
- distal
embolization
5. Vasculitis / autoimmune disease
Large vessel vasculitis
- Takayasu
arteritis
- Giant
cell arteritis
Small vessel disease
- scleroderma/CREST
- SLE
- Sjögren
- rheumatoid
vasculitis
- mixed
connective tissue disease
6. Hemodialysis access-induced distal ischemia (HAIDI)
AKA:
- dialysis
access steal syndrome (DASS)
พบหลัง AV access creation
Symptoms:
- coolness
- pain
- ulcer
- gangrene
Risk สูงใน:
- brachial-based
AV access
- DM
- PAD
7. COVID-19 related thrombosis
arterial thrombosis ได้แม้ respiratory
symptoms ไม่มาก
Acute upper extremity ischemia
Clinical presentation
Classic 6 Ps
Pain
earliest sign
Pallor
Poikilothermia
Pulselessness
Paresthesia
early nerve ischemia
Paralysis
late ominous sign
Important clues
Embolic disease
- sudden
onset
- unilateral
- absent
radial pulse
- contralateral
arm normal
Location of embolus
Proximal brachial occlusion
→ whole
arm ischemia
Distal brachial bifurcation
→
forearm/hand ischemia
Chronic upper extremity ischemia
Exertional symptoms
Arm claudication
exercise-induced arm fatigue/pain
Subclavian steal syndrome
Pathognomonic for proximal subclavian occlusion
Mechanism:
retrograde vertebral artery flow
Symptoms
- dizziness
- syncope
- neurologic
symptoms during arm exercise
Exam
- BP
difference between arms
- weak
ipsilateral pulses
Digital ischemia / gangrene
Usually from:
- emboli
- vasculitis
- autoimmune
disease
- dialysis
steal syndrome
proximal atherosclerotic occlusion rarely causes digital
gangrene
Physical examination
Essential components
Pulse examination
- subclavian
- axillary
- brachial
- radial
- ulnar
compare both arms
Bilateral arm blood pressure
Difference 30–40 mmHg
→ suggests proximal
subclavian occlusion
Doppler examination
absence of distal Doppler signals
→ severe ischemia
Wrist-brachial index (WBI)
Severe ischemia
WBI <0.4
Neurologic examination
ประเมิน:
- sensation
- motor
function
motor deficit/paralysis
= advanced ischemia
Diagnosis
Clinical diagnosis ทำได้ ~90% จาก:
- history
- vascular
exam
- pulse
asymmetry
- risk
factors
Important diagnostic clues
Sudden unilateral ischemia
→
embolus likely
Chest pain + left arm ischemia
→ think
aortic dissection
Symmetric pulse reduction
→
systemic disease/vasculitis
Imaging
Acute ischemia
CTA
rapid evaluation
Catheter angiography
gold standard
- therapeutic
option
Angiographic clues
Embolus
- sharp
cutoff
- rounded
meniscus
- no
collateral circulation
Thrombosis
- tapered
cutoff
- collateral
vessels often present
Chronic ischemia imaging
- Duplex
ultrasound
- CTA/MRA
- digital
plethysmography
- pulse
volume recording
Differential diagnosis
Stroke/TIA
may mimic ischemia
Compartment syndrome
pain out of proportion
Complex regional pain syndrome
pain/swelling but pulses preserved
Frostbite
Venous phlegmasia
Severity classification
ใช้ Rutherford classification เช่นเดียวกับ lower extremity
Class I
viable limb
Class IIa
marginally threatened
Class IIb
immediately threatened
Class III
irreversible ischemia
Treatment approach
Acute ischemia
Initial management
Immediate IV unfractionated heparin
unless contraindicated
Revascularization indications
- threatened
limb
- neurologic
deficit
- persistent
ischemia
Methods:
- embolectomy
- thrombectomy
- thrombolysis
- endovascular
repair
- bypass
surgery
Chronic ischemia
Atherosclerotic disease
optimal medical therapy:
- antiplatelet
- statin
- BP
control
- smoking
cessation
Dialysis access steal syndrome
may require:
- access
revision
- DRIL
procedure
- ligation
Vasculitis
treat underlying inflammatory disease
Important clinical pearls
Upper extremity ischemia ≠
atherosclerosis only
Always think about:
- embolism
- vasculitis
- thoracic
outlet syndrome
- autoimmune
disease
- dialysis
access steal
Sudden unilateral cold pulseless arm
→
cardioembolic disease until proven otherwise
Large BP difference between arms
→
proximal subclavian stenosis/occlusion
Digital ischemia
strongly associated with autoimmune disease
Hand ischemia after AV fistula
consider DASS/HAIDI immediately
High-yield associations
|
Condition |
Classic clue |
|
AF embolus |
sudden pulseless painful arm |
|
Subclavian steal |
dizziness with arm exercise |
|
Arterial TOS |
young patient + cervical rib |
|
Takayasu |
young woman + pulse deficit |
|
GCA |
elderly + headache/jaw
claudication |
|
Scleroderma |
Raynaud + digital ischemia |
|
Dialysis steal |
ischemic hand after AV access |
