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TEST TAKING TIP

Test Taking Tip

  • Vascular emergency questions are asked twice as much as elective vascular reconstruction. Acute ischemia and traumatic injury are favorite topics along with management. If in doubt, perform fasciotomy. Other common topics are risk factor modification, vascular lab testing (ABI), and visceral aneurysm. Endovascular choices are often wrong; be careful not to select an answer just because you don't fully understand it.

PERIPHERAL ARTERIAL OCCLUSIVE DISEASE

Describe the risk factors associated with atherosclerosis:

  • Smoking, diabetes, hyperlipidemia, obesity, HTN, sedentary lifestyle

Differentiate between the following:

  • Arterial ulcers and venous ulcers

  • Arterial ulcers—painful and usually occur on toes or foot

  • Venous ulcers—commonly broad-based, shallow at medial malleolus

  • Claudication and rest pain

  • Claudication—cramping ischemic muscle pain with exertion that occurs distal to arterial stenosis, associated with 1% risk of limb loss and 5% mortality.

  • Rest pain—also due to ischemia, arises without exertion and classically wakes patients from sleep (often over distal metatarsals). The pain may resolve with standing or placing foot over side of bed (dependent position, gravity). >50% patients eventually require amputation.

  • Wet gangrene and dry gangrene

  • Dry gangrene—dry necrotic "mummified" tissue without signs of infection—not a surgical emergency

  • Wet gangrene—moist necrotic tissue indicative of active infectious process—requires aggressive debridement or amputation to avoid sepsis

How are ankle brachial index/digital brachial index (ABIs/DBIs) and segmental pressures measured? Pulse volume recordings (PVRs)? What is their significance?

  • Normal ABI at rest: 1.0 to 1.2, mild arterial insufficiency: 0.7 to 0.9, claudication: 0.5 to 0.7, rest pain and ultimately tissue necrosis: <0.4 (falsely elevated ABIs may be seen in diabetic patients or those with chronic renal disease due to extensive vascular calcification).

  • PVRs analyze the waveforms at sequential sites along patient's leg—triphasic or biphasic waveforms, indicates more perfusion than monophasic.

FIGURE 24-1.

Calculating the ankle-brachial index. (Reproduced from Brunicardi FC, Andersen DK, Billiar TR, et al. Schwartz's Principles of Surgery. 9th ed. http://www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)

What is the half-life of heparin? Intraoperative therapeutic dosing? How is it reversed?

  • Half-life is 60 to 90 minutes. Intraoperative dosing is 70 to 100 units/kg (activating clotting time of 250 to 350 seconds if measured). Protamine sulfate: 1 mg/100 units of heparin.

What are the 5-year patencies of common and external iliac percutaneous transluminal angioplasty (PTA) without stenting?

  • Common iliac: 70% to 80%

  • External iliac: 50% to 60%

What are the classic signs/symptoms of acute arterial occlusion? In what order do they present?

  • The "6 P's" include: Paresthesias, Pain, Pallor, Poikilothermia, Pulselessness, Paralysis

What percentage of emboli originate in the heart? First and second most common causes?

  • 80% of peripheral emboli are due to cardiac etiology (First—atrial fibrillation, Second—acute MI)

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