Vascular Surgery

·         ATHEROSCLEROSIS

1. The classic risk factors for atherosclerotic cardiovascular disease include tobacco use, hyperlipidemia, hypertension, diabetes mellitus, and family history of cardiovascular disease.
2. It is estimated that 10% of the coronary artery disease in the general population is attributable to homocysteine.
3. The bacteria implicated in atherosclerosis include Chlamydia pneumoniae, Heliobacter pylori, streptococci, and B. typhosus.

·         ABI is the highest ankle pressure (anterior tibial or posterior tibial artery) divided by the higher of the two brachial pressures. The normal ABI is slightly > 1 (1.10). An ABI of 1.0-0.5 is typical of patients with claudication. Patients with rest pain have an ABI < 0.5, and patients with tissue necrosis often have an ABI much lower.

·         A TIA is a neurologic deficit that lasts < 24 hours. Most TIAs last only 15-30 seconds.

RIND lasts longer than 24 hours and completely resolves within 1 week (usually within 3 days).

CVA, or acute stroke, is a stable neurologic deficit that may show gradual improvement over a long period.

·         Hollenhorst plaques:

They are bright yellow plaques of cholesterol, usually at a branch point in the retinal vessels, that have embolized from the carotid bifurcation. Clinically, this finding indicates that the atheromatous plaque in the carotid is quite friable. Further embolization may occur with manipulation at the time of surgery.

·         Surgery is strongly indicated for symptomatic carotid artery disease associated with > 70% stenosis. The absolute risk reduction of stroke is 17% at 2 years. Recent data also suggest a smaller benefit in patients with symptomatic stenoses of 50-69% (6.5% risk reduction at 5 years). Patients with stenosis of < 50% do not benefit from surgery.

·         When the internal carotid artery is occluded, The periorbital branches of the external carotid artery form communications with the ophthalmic artery, a branch of the internal carotid and reestablish circulation in the circle of Willis?

·         First successful surgical procedure of the extracranial carotid artery performed in 1954 by Eastcott.

·         ABDOMINAL AORTIC ANEURYSM

1. An AAA is defined as a ≥ 50% increase in normal aortic diameter.
2. Forty percent of patients with a popliteal artery aneurysm harbor an AAA.
3. CT is the single best imaging modality to plan an AAA repair.
4. AAA should be repaired electively when the size reaches 5.5 cm in diameter.
5. A 5-cm diameter AAA has an annual rupture risk of < 1%. The risk of AAA rupture increases with size. Annual rupture risk is 10% for a 6-cm AAA and 30% for AAAs > 7 cm.

·         In patients with a documented, recurrent pulmonary embolism while taking adequate anticoagulation therapy or with an absolute contraindication to anticoagulation, an IVC filter can be placed to prevent embolization or propagation of clot to the lungs. A significant rate of recurrent DVT has been associated with IVC filters.

·         May-Thurner syndrome: Iliofemoral venous thrombosis is characterized by unilateral pain and edema of an entire lower extremity, discoloration, and groin tenderness. A total of 75% of the cases of iliofemoral venous thrombosis occur on the left side, presumably because of compression of the left common iliac vein by the overlying right common iliac artery.

In phlegmasia alba dolens (literally, painful white swelling), the leg becomes pale and white. Arterial pulses remain normal. Progressive thrombosis may occur with propagation proximally or distally and into neighboring tributaries. The entire leg becomes both edematous and mottled or cyanotic. This stage is called phlegmasia cerulea dolens (literally, painful purple swelling). When venous outflow is seriously impeded, arterial inflow may be reduced secondarily by as much as 30%. Limb loss is a serious concern; aggressive management (i.e., venous thrombectomy, catheter-directed lytic therapy, or both) is necessary.

·         Duplex ultrasound uses both image and velocity data (hence the name duplex) in a nearly simultaneous presentation of ultrasound echo images (B-mode ultrasound) and blood velocity waveforms obtained by Doppler ultrasound. The Doppler signals are obtained from a single small region of the blood vessel. Average velocities can be estimated for multiple such regions over a large area of the vessel. By assigning colors to the velocities, blood flow can be visually represented. Such a presentation, called colorflow duplex ultrasound, aids the duplex examination but cannot replace the information obtained from the Doppler velocity waveform.

·         UNIVERSITY OF WASHINGTON CRITERIA is used for carotid artery stenosis.

·         Pulse volume recording (PVR) is a pneumoplethysmographic technique that tracks the limb volume changes over the cardiac cycle. It measures the segmental pressure changes with pneumatic cuffs as a function of the limb volume changes. The relative PVR amplitudes identify the presence of peripheral artery disease and localize the arterial segment involved. The PVR is unaffected by medial calcification. Great-toe pressure also may be used to diagnose and assess disease severity in diabetic patients because medial calcification rarely affects the digital arteries.

·         Venous occlusion plethysmography or impedance plethysmography (IPG) has high sensitivity and specificity in detecting occlusive thrombi above the knee, particularly for iliofemoral occlusive thrombi (95%). Because IPG provides functional information about deep venous outflow from the legs, it provides diagnosis of nonvisualized caval or iliac thrombosis, diagnosis of recurrent acute proximal thrombosis superimposed on chronic thrombosis, and functional evaluation of residual or chronic outflow obstruction (venous claudication).