Occlusive Arterial Disease

1. Occlusive Arterial Disease Tintinalli Chap. 64

2. Acute Limb Ischemia • True medical emergency • Thrombosis or embolism • Critical limb ischemia • 1-year mortality > 25% • 25% of survivors require amputation

3. Epidemiology • National Health and Nutrition Examination Survey (NHANES) • Prevalence in U.S. • 4.3% > 40 • 15.5% > 70 • Peripheral Arterial Disease Awareness, Risk, and Treatment: New Resources for Survival (PARTNERS) • Studied high-risk populations • Prevalence was 29%

4. Risk Factors • Age • Men • Smoking history (80%) • Diabetes • Hyperlipidemia • Hypertension • Hyperhomocysteinemia • Elevated C-reactive protein

5. Pathophysiology • Lack of blood supply • Ultimately leads to cell death and irreversible tissue damage • Peripheral nerves and skeletal muscle are most sensitive • Irreversible change occurs within 6 hours of anoxia at room temperature

6. Causes • Reperfusion injury • d/t formation of oxygen radicals • Myoglobinemia, renal failure, muscle infarction • Hyperkalemia, myoglobinemia, metabolic acidosis, elevated CK • 1/3 of all deaths froom occlusive arterial disease • Non-embolic limb ischemia • Atherosclerosis • Intra-arterial drug injection • Thoracic aortic dissection • Hypercoaguable states • Embolism

7. Specific Conditions • Trash foot/Blue Toe Syndrome • Vasculitis (RA, SLE, PN) • Raynaud disease • Takayasu arteritis • Thromboangiitisobliterans (Buerger disease) • HIV arteritis • Hypothenar hammer syndrome • Popliteal artery entrapment • External iliac artery endofibrosis • Local Arterial Trauma • Shock-related arterial ischemia

8. Embolism • 80-90% originate from the heart • Atrial fibrillation • Mural thrombus following recent MI • Mechanical valve • Tumor emboli (atrial myxoma) • Vegetations • Prosthetic cardiac devices • Noncardiac • Thrombi from aneurysms/atheromatous plaques • Intra-arterial drug injection

9. Clinical Features • Six P’s • Pain • Pallor • Followed by blotchy, mottled areas of cyanosis, petechiae, and blisters • Paralysis • Pulselessness • Paresthesias • Pokilothermia

10. Acute vs. Chronic Disease Claudication Acute Limb Ischemia Not well localized Not relieved by rest or gravity Can be a worsening of chronic pain • Cramplike pain, ache, or tiredness • Brought on by exercise • Resolves within 2-5 minutes of rest • Re-occurs at consistent walking distances

11. Differential • Neurogenic claudication • Spinal stenosis or lumbosacral radiculopathy • Worse with erect posture • DVT • Phlegmasiaceruleadolens (painful blue inflammation) • Massive iliofemoral thrombosis and high compartment pressures • Extremely swollen cyanotic leg, venous insufficiency • Phlegmasia alba dolens (milk leg) • Pregnancy • Massive iliofemoral thrombosis with arterial spasm • Pale white leg

12. Diagnosis • Clinical – consult vascular surgery prior to confirmatory imaging • Capillary refill • Doppler • Ankle-brachial index (Normal: 0.9-1.3) • < 0.25 suggests potentially limb-threatening disease • Segmental blood pressures

13. Diagnosis • BMP • EKG • Coags • Cardiac enzymes • Cardiac monitoring • Echo • Arteriogram - confirmatory

14. ED Treatment • Unfractionated Heparin • 80 units/kg bolus then 18 units/kg/hr • Aspirin • Dependent positioning • Pain control • Environment protection

15. Definitive Treatment • Catheter-directed thrombolysis • Percutaneous mechanical thrombectomy • Percutaneous transluminal angioplasty (PTA) • Standard surgery • Remains the gold standard

16. Treatment of Chronic Disease • Smoking cessation • Exercise • Medications • Cholesterol • Blood pressure • Glucose • Aspirin – reduces vascular mortality 25%