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acute peripheral arterial occlusion (severe acute limb ischemia)

Sudden onset of severe limb ischemia. Etiology: 1) thrombosis a) may form at site of stenosis in an atherosclerotic artery or bypass graft b) procoagulant disorders may cause thrombus formation in normal arteries 1] heparin-induced thrombocytopenia 2] antiphospholipid antibody syndrome 3] hyperhomocysteinemia 2) embolism a) most common cause b) 85% originate from cardiac thrombi c) systemic emboli from deep venous thrombosis (DVT) that enters arterial circulation via a patent foramen ovale or an atrial septal defect (ASD) d) emboli originating from aneurysms of the aorta or peripheral arteries 3) dissection 4) trauma Pathology: - progression of severe atherosclerosis with superimposed arterial thrombosis or arterial embolization - irreversible changes occur as early as 4-6h after acute arterial occlusion Clinical manifestations: 1) pulseless 2) painful -> paresthesia -> complete sensory loss with necrosis 3) pallor 4) paralysis 5) poikilothermy (coolness) Radiology: - arteriography (angiography) a) anticoagulation with heparin prior to arteriography b) identify the site & nature of acute arterial occlusion c) distinguish thrombosis in situ from arterial embolism Complications: - tissue necrosis - compartment syndrome from tissue swelling after reperfusion [1] Management: 1) severe claudication but no pain at rest a) anticoagulation with heparin & b) antiplatelet therapy 2) revascularization in a threatened, but viable limb [1,2] a) angioplasty or embolectomy catheter b) intra-arterial thrombolytic therapy 1] urokinase or tPA better than streptokinase 2] 82% salvage rate at 1 year 3) surgical reconstruction (bypass) when angioplasty/embolectomy & thrombolysis are not feasible or ineffective 4) below-the-ankle interventions are feasible & provide good clinical outcome [7] 5) careful monitoring after reperfusion - frequent reocclusion, limb edema, compartment syndrome 6) amputation if limb not viable [1,2] a) anesthesia, paralysis, absent doppler, muscle rigor b) blacks more likely than hispanics or whites to undergo limb amputation [3]

General

critical limb ischemia

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2015, 2018, 2022.
  2. BASIL Trial Participants. Bypass versus angioplasty in severe ischaemia of the leg (BASIL): Multicentre, randomised controlled trial. Lancet 2005; 366:1925 PMID: 16325694 - Goy JJ & Urban P Life and limb: Bypass versus angioplasty in the ischaemic limb. Lancet 2005; 366:1905 PMID: 16325681
  3. Durazzo TS et al Influence of Race on the Management of Lower Extremity Ischemia. Revascularization vs Amputation. JAMA Surg. 2013;():1-6. March 20, 2013 PMID: 23552850 http://archsurg.jamanetwork.com/article.aspx?articleid=1669979
  4. Feiring AJ, Krahn M, Nelson L et al Preventing leg amputations in critical limb ischemia with below-the-knee drug-eluting stents: the PaRADISE (PReventing Amputations using Drug eluting StEnts) trial. J Am Coll Cardiol. 2010 Apr 13;55(15):1580-9. PMID: 20378075
  5. Creager MA, Kaufman JA, Conte MS. Clinical practice. Acute limb ischemia. N Engl J Med. 2012 Jun 7;366(23):2198-206. PMID: 22670905
  6. Lou N. Revascularization Feasible for Below-The-Ankle CLI Limbs salvaged in most severe cases per single-center study MedPage Today. March 20, 2018 https://www.medpagetoday.com/meetingcoverage/sir/71890 - Arslan B, et al Midterm outcomes after below the ankle interventions for Rutherford 5-6 critical limb ischemia patients. Society of Interventional Radiology (SIR) 2018.
  7. Misra S, Shishehbor MH, Takahashi EA, et al AHA SCIENTIFIC STATEMENT. Perfusion Assessment in Critical Limb Ischemia: Principles for Understanding and the Development of Evidence and Evaluation of Devices. A Scientific Statement From the American Heart Association. Circulation. Aug 2019 PMID: 31401843 https://www.ahajournals.org/doi/pdf/10.1161/CIR.0000000000000708