Basic Science Peripheral Vascular Disease

1. Basic Science Peripheral Vascular Disease Kashaf Sherafgan PGY 2 November 17th 2005

2. Peripheral Arterial Occlusive Disease Basic Considerations

3. Atherosclerosis - Risk factors Hypercholesterolemia Diabetes Hypertension Smoking Relative factors - advanced age, male gender, hypertriglyceridemia, hyperhomocysteinemia, sedentary lifestyle, family history

4. Pathophysiology of Atherosclerosis Atheroma � porridge; Sclerosis � hardening Response to endothelial injury hypothesis Loss of barrier function, antiadhesive properties and antiproliferative influence on underlying SMCs Migration and proliferation of SMCs ? production of ECM Oxidized lipid accumulation in vessel walls Recruitment of macrophages and lymphocytes Adherence of platelets to dysfunctional endothelium, exposed matrix, and macrophages

5. Critical Diameter Adaptive arterial enlargement preserves luminal caliber until a critical plaque mass is reached

6. Diagnostic Modalities Non-invasive ABIs Segmental limb pressures Limb plethysmography Exercise testing Doppler & duplex ultrasound MR angiography Invasive Contrast arteriography CT angiography

7. Ankle-Brachial Index Comparison of ankle pressure to brachial SBP Reproducible, useful for long term surveillance Normal 0.85-1.2 Claudicants 0.5-0.7 Critical ischemia < 0.4 May be falsely elevated in calcified vessels (DM)

8. ABI algorithm

9. PVR Calibrated air plethysmographic wave form recording system Helps localize site of obstruction Placement of cuffs at levels of proximal and distal thigh, calf and ankle

10. Medical Therapy Risk factor management Lipid-lowering therapy Smoking cessation Exercise regimen Antiplatelet therapy - ASA, ticlodipine, clopidogrel Vasoactive - Cilostazol (Pletal), pentoxyfilline (Trental)

11. Surgical Interventions

12. Peripheral Arterial Occlusive Disease Carotid Stenosis

13. Question A patient with symptomatic 85% carotid stenosis is found to have asymptomatic 50% stenosis on the contralateral side. Appropriate initial treatment includes: A. Simultaneous bilateral CEA B. Staged bilateral CEA with 1 week interval between stages C. CEA on symptomatic side only D. CEA on side of greatest stenosis regardless of symptoms

14. Question A patient with symptomatic 85% carotid stenosis is found to have asymptomatic 50% stenosis on the contralateral side. Appropriate initial treatment includes: A. Simultaneous bilateral CEA B. Staged bilateral CEA with 1 week interval between stages C. CEA on symptomatic side only D. CEA on side of greatest stenosis regardless of symptoms

15. Stroke Third leading cause of death Major modifiable risk factors HTN Smoking Carotid stenosis Cardiac diseases - a-fib, endocarditis, MS, recent MI Atherosclerosis = leading cause of ischemic stroke Artery-to-artery emboli Thrombotic occlusion Hypoperfusion from advanced stenosis

16. CarotidStenosis Causes of atherosclerosis at bifurcation Low wall shear stress Flow separation Complex flow reversal along posterior wall of sinus Sequence of events b. Establishment of plaque c. Soft, central necrotic core with overlying fibrous cap d. Disruption of cap - necrotic cellular debris and lipid material become atherogenic emboli e. Empty necrotic core becomes a deep ulcer = thrombogenic ? thromboembolism

17. Presentation Asymptomatic bruit Amaurosis fugax � transient monocular visual disturbance Lateralizing TIA Crescendo TIA Stroke-in-evolution CVA

18. Diagnostic Algorithm

19. Duplex Scanning B-mode scan � Anatomic information Doppler � Flow velocities Plague ? Increased peak and range of velocities

20. Indications for CEA Symptomatic � TIA, AF, small stroke Proven � Stenosis > 70% Acceptable � Stenosis 50-69% Lesser symptoms, failed medical therapy Asymptomatic Proven � Stenosis > 60%, good risk Uncertain High risk patient Surgeon morbidity-mortality >3% Combined carotid coronary operation Non-stenotic ulcerative lesions Presence of ulceration or contralateral occlusion may lower threshhold for surgery

21. Peripheral Arterial Occlusive Disease Chronic Occlusive Disease of the Lower Extremities

22. Question Which of the following is an indication for bypass? A. Claudication within � block B. ABI of 0.5 C. Rest pain D. Occlusion of the superficial femoral and anterior tibial arteries

23. Question Which of the following is an indication for bypass? A. Claudication within � block B. ABI of 0.5 C. Rest pain D. Occlusion of the superficial femoral and anterior tibial arteries

24. Prevalence and survival 2-3% population >50y, 10% > 70y Lower extremity ischemia associated with decreased 5-yr survival 97.4 % intermittent claudication 80% claudication requiring surgery 48% limb-threatening ischemia 12% re-op for limb-threatening ischemia

25. Signs and symptoms Claudication Extremity pain, discomfort or weakness Consistently produced by the same amount of activity Relieved with rest Rest pain Localized to metatarsal heads and toes Worse with elevation or recumbent position Improved with foot dependency

26. Temperature Hair loss Pallor Nail hypertrophy Ulcer Gangrene Dry - non infected black eschar Wet - tissue maceration and purulence

28. Diagnostic algorithm

29. Question Late vein graft failure is due to: A. Atherosclerotic changes in the vein B. Vein thrombosis C. Fibrointimal hyperplasia D. Kinking of the vein graft

30. Question Late vein graft failure is due to: A. Atherosclerotic changes in the vein B. Vein thrombosis C. Fibrointimal hyperplasia D. Kinking of the vein graft

31. Graft Autologous Vein Graft - SV, arm vein Synthetic - PTFE, Decron Graft failure 30 days - Technical error 30 days to 2 years - Intimal hyperplasia >2 years - Progression of atheresclerosis Surveillance Duplex 6 wks peri-op, 3 months/2 yrs, q 6 month

32. Peripheral Arterial Occlusive Disease Acute Thromboembolic Disease

33. Question 86 yo F with PMHx CAD, HTN, DM, A fib presents w/ sudden onset left lower extremity pain. Palpable femoral pulses. No palpable or doppler signals on left. Nl on right. Where is her obstruction? A. Common femoral artery B. Popliteal artery C. Iliac bifurcation D. Superficial femoral artery

34. Question 86 yo F with PMHx CAD, HTN, DM, A fib presents w/ sudden onset left lower extremity pain. Palpable femoral pulses. No palpable or doppler signals on left. Nl on right. Where is her obstruction? A. Common femoral artery B. Popliteal artery C. Iliac bifurcation D. Superficial femoral artery

35. Epidemiology Incidence: 1.7 cases / 10,000 people / Yr. Elderly Male > female Mortality 15%, Amputation 10-30% Medical co-morbidities common CVD 12%, CAD 45%, DM, 31%, HTN 60%, CHF 13%

36. Sites of Embolization Bifurcations Femoral - 40% Aortic - 10-15% Iliac - 15% Popliteal - 10% Upper extremities - 10% Cerebral - 10-15% Mesenteric/visceral - 5%

37. History The onset and duration of symptoms Pain Sudden onset - embolic Long-standing before acute event - thrombotic Previous revascularization Risk factors for atherosclerotic heart disease

38. 6 Ps Pain Pallor Pulselessness Paresthesia Paraparesis Poikilothermia

40. Management Arteriography Operative planning � target vessel Therapeutic � thrombolysis, angioplasty Should not delay revascularization & may be obtained intra-operatively Rapid systemic anticoagulation Heparin bolus/drip Prevent propagation of thrombus, distal thrombosis, venous thrombosis Surgery- Embolectomy Percutaneous Thrombectomy

41. Question 6 hours after a femoral-tibial artery bypass for advanced acute ischemia, the lower leg is swollen and painful with palpable pulse. The likely etiology is: A. DVT B. Reperfusion injury C. Thrombosis D. Arterial spasm

42. Question 6 hours after a femoral-tibial artery bypass for advanced acute ischemia, the lower leg is swollen and painful with palpable pulse. The likely etiology is: A. DVT B. Reperfusion injury C. Thrombosis D. Arterial spasm

43. Reperfusion injury Local effects Oxygen radicals accumulate Compound cellular insult Systemic effects Acid, potassium, cytokines, cardiodepressants accumulate in ischemic limb Sudden cardiac arrhythmias Renal failure Acute lung injury

44. Prevention and management Hydration UO 100cc/hr Alkalinization of urine Prevent myoglobin precipitation in renal tubules Mannitol Antioxidant, osmotic diuretic Insulin/glucose Fasciotomy

45. Question Regarding compartment syndrome, which of the following is correct? A. The leg is divided into two compartments--anterior and posterior B. The most commonly affected compartment is the posterior C. The earliest manifestation of acute compartment syndrome is pain D. Patients with compartment pressures greater than 15 mm Hg should undergo fasciotomy

46. Question Regarding compartment syndrome, which of the following is correct? A. The leg is divided into two compartments--anterior and posterior B. The most commonly affected compartment is the posterior C. The earliest manifestation of acute compartment syndrome is pain D. Patients with compartment pressures greater than 15 mm Hg should undergo fasciotomy

47. 4 compartments: Anterior Lateral (Peroneal) Deep Posterior Superficial Posterior

48. Pathophysiology

49. Signs and symptoms Pallor and pulselessness Not always reliable Distal pulses may be present Paralysis - Late symptom Pain - Severe and out of proportion, increased on passive motion Paresthesia - Numbness, weak dorsiflexion, numbness in 1st dorsal web space Tender, swollen, tense muscle compartments

50. Indications for fasciotomy Classically > 40-45 mm Hg at any point or > 30 mm Hg for 3-4 hrs Arterial perfusion pressure is paramount Mean arterial pressure - interstitial pressure < 30 mm Hg is critical Diastolic pressure - compartment pressure < 20 mm Hg is critical

51. Fasciotomy

52. Thoracic Outlet Syndrome

53. Question The most common finding associated with thoracic outlet syndrome is: A. Signs of brachial plexus nerve injury B. Subclavian vein thrombosis C. Subclavian artery aneurysm D. Presence of cervical rib on chest XR

54. Question The most common finding associated with thoracic outlet syndrome is: A. Signs of brachial plexus nerve injury B. Subclavian vein thrombosis C. Subclavian artery aneurysm D. Presence of cervical rib on chest XR

55. Anatomy Interscalene triangle - artery and nerves Costoclavicular space - vein Subcoracoid area - artery, vein, nerves

56. Thoracic Outlet Syndrome Upper extremity symptoms due to compression of the neurovascular bundle in the thoracic outlet area 3 Types Neurogenic - most common (95%) Venous 2-3% Arterial 1% Exacerbated by elevation, abduction, hyperextension of arm

57. Etiology Bone - cervical rib, long transverse process of C7, abnormal first rib, osteoarthritis Muscles - scalene anomalies Trauma - neck hematoma, bone dislocation Fibrous bands - congenital and acquired Neoplasm Narrowing of the costoclavicular space Subclavius muscle, costoclavicular ligament, hypertrophic callus

58. Management Conservative Improvements in postural sitting, standing, and sleeping position Behavior modification at work Muscle stretching and strengthening exercises Successfully treats 50-90% of patients Surgery - Transaxillary first rib resection

59. Buerger�s Disease

60. Question Which of the following characteristics of Buerger�s disease is true? A. Most commonly observed in young non-smoking females B. It affects mainly the large arteries of the upper ext C. Is characterized by sharply segmental acute and chronic vasculitis of medium-sized and small arteries D. Vascular reconstructive surgery is the main therapy E. Arterial involvement progresses in a proximal to distal fashion

61. Question Which of the following characteristics of Buerger�s disease is true? A. Most commonly observed in young non-smoking females B. It affects mainly the large arteries of the upper ext C. Is characterized by sharply segmental acute and chronic vasculitis of medium-sized and small arteries D. Vascular reconstructive surgery is the main therapy E. Arterial involvement progresses in a proximal to distal fashion

62. Buerger�s Disease Thrombangiitis Obliterans Exclusively associated with cigarette smoking More prevalent in Middle East and Asia Occlusive lesions seen in muscular arteries, with a predilection for tibial vessels Presentation - rest pain, gangrene and ulceration

63. Buerger�s Disease Recurrent superficial thrombophlebitis (�phlebitis migrans�) Young adults, heavy smokers, no other atherosclerotic risk factors Angiography - diffuse occlusion of distal extremity vessels Progression - distal to proximal

64. Buerger�s Disease - Management Revascularization options are limited Clinical remission with smoking cessation Sympathectomy has a limited role in patients with ulcerations