inpatient / cardiology

Acute Limb Ischemia

Last Updated: 1/23/2023

# Acute Limb Ischemia

-- ABCs: 
consult surgery or vascular surgery immediately if any c/f ischemia (threatened limb) or compartment syndrome
-- Chart Check: prior echos, LE procedures, AC use
-- HPI Intake: timing, pain, poikilothermia, pallor, paresthesia, paralysis; h/o AFib, prior clotting,
-- Can't Miss: threatened and non-viable limbs that require surgical attention; compartment syndrome
-- Admission Orders: CBC, BMP, coags, T+S, lactate, CTA with runoff, consider echo if c/f AFib or LV thrombus
-- Initial Treatment to Consider: heparin

-- History: *** PAD, stents, AF, atherosclerosis, hypercoagulability - APS, HITT, malignancy
-- Clinical/Exam: *** irregular rhythm, pulses, cap refill, ulcers decreased hair growth, dopplers, 5 P’s - pain, poikilothermia, pallor, paresthesia, paralysis
-- Data: *** coags, creatinine, lactate; EKG, CTA with runoff
-- Etiology/DDx: *** embolic >> thrombotic; dissection, proximal aneurysm, compartment syndrome

The patient's HPI is notable for ***. Exam showed ***. Labwork and data were notable for ***. Taken together, the patient's presentation is most concerning for ***, with a differential including ***.

-- f/u CBC, BMP, coags, type and screen, lactate
-- f/u CTA if limb is viable or threatened
-- f/u echo if c/f cardiac thrombus
-- Serial doppler exams
-- if revascularization procedure - monitor for reperfusion injury - acidosis, hyperK, myoglobinemia, ATN, compartment syndrome

-- IV heparin drip titrated to PTT 60-80; f/u PTT q6-8 hours
-- f/u vascular surgery recs re: revascularization (catheter-directed thrombolysis vs thromboembolectomy) or amputation

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If You Remember Nothing Else

Acute limb ischemia mostly presents in the lower extremities and is more likely caused by an embolism vs thrombosis, as emboli acutely occlude vessels that have not had time to form collaterals. If you suspect limb ischemia based on the 5 P's (pain, pallor, pulses, paralysis, poikilothermia), get dopplers ASAP and call vascular surgery. Depending on how threatened the limb is, a CTA with runoff is usually needed for planning and appeciating collateral circulation. While treatment if often surgical to relieve obstruction, heparin will prevent further clot from propagating.

Clinical Pearls

  • A sudden decrease in limb perfusion that threatens viability - much more commonly caused by embolism over thrombosis
  • Lower limbs are >80% of cases
  • Those who have thrombosis usually less severe as its chronic from underlying PAD and there has been time for collaterals to form
  • The 5 P’s: Pain - worsens with passive movement; Pallor - initially pale, then blue and mottled; Pulses - absent distal to occlusion; Paralysis - initially weakness, then progresses to irreversible paralysis; Poikilothermia - cool extremity, but depends on environment
  • While the limb is still viable, it will only have mid-moderate pain and dopplers present; when threatened it will have all of the 5 P’s developing, and when nonviable it will have a complete loss of sensation, paralysis, no pain
  • Prolonged treatment with vasopressors can lead to vasospasm of distal arterioles leading to ischemia and necrosis of most distal aspects of extremities (toes, fingers)
  • Leriche Syndrome (aortoiliac occlusive disease) - occlusion at the level of aortic bifurcation that presents with pain in legs and buttock, erectile dysfunction, often shock
  • Risks of PAD are smoking, DM, HLD, increased age (20% prevalence in those >70yo)
  • Classic claudication (10-35%) in PAD is exertional pain distal to the site of occlusion, relieved by rest; atypical pain is more common (40-50%), and asymptomatic in 20-50%
  • Screen for PAD with ABIs - abnormal is <0.9; >1.3 implied decreased compressibility due to calcification - if abnormal get segmental ABI with pulse volume recordings (PVRs) which helps localize the disease followed by CTA with runoff or angiography to help with planning for possible revascularization

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