Arterial Disease Flashcards

Question

Arterio-Venous Fistulas

Answer 1

For dialysis High flow rate Take time to mature Risk of steal/aneurysm

Answer 2

Popliteal artery compressed by heads of gastrocnemius muscle Occurs on exercise or knee extension Usually young athletic patients Caused by anomalous course of vessel / muscle head If uncorrected may lead to occlusion / distal embolus

Answer 3

A cyst-like structure within the adventitial layer of the artery wall Usually occurs in the popliteal artery Rare, usually males, fourth decade in life Clinical appearance of calf pain Treatment by surgical resection

Answer 4

Affects small and medium sized arteries of the limbs Predominantly young males 20 – 40yrs Usually heavy smokers – auto-immune response to tobacco Long string-like arteries with inadequate collaterals

Answer 5

Compression of the subclavian artery/vein and nerve Positional Cervical rib, trauma, muscular hypertrophy, repetitive injury Can result in DVT/claudication/numbness/cold fingers Resection of cervical rib/stenting

Answer 6

Acute/chronic Ischaemia & gangrene of bowel wall Extreme abdominal pain on eating +/- nausea & vomiting Patients very thin – avoid eating Thrombolysis/angioplasty/stenting/ bypass surgery

Answer 7

Obesity Calcified vessels Ulceration/gangrene Recent surgery/intervention Tortuous vessels / anatomical variants Bowel gas (aorto-iliac segment) Pain

Answer 8

Arteriography Duplex ultrasound CT MRI Doppler spectral analysis

Answer 9

Gold Standard examination (?) Costly Invasive Time consuming Has morbidity / mortality Delivers radiation and contrast Technical limitations Requires aftercare But can be combined with intervention

Answer 10

Costly Limited availability Contrast delivered Radiation exposure (CT) Patient tolerance issues

Answer 11

Pulsed wave Doppler Shows anatomy and functional information Identifies specific lesions Differentiates diffuse and focal disease Identifies other pathology Competes with arteriography Takes longer and is more costly than continuous wave Can be used for ‘specific’ purposes

Answer 12

High resistance flow pattern (muscle beds) Plug flow in the Aorta, parabolic flow distally Triphasic waveform - Result of arterial compliance and propagation of pulse pressure wave Age related changes -Biphasic waveform Various indices can be utilised Vasodilation affects the degree of diastolic flow Proximal disease Prolongs acceleration time (damping) and reduces velocity Reduces resistance due to distal vasodilation Distal disease Increases resistance and affects deceleration

Answer 13

Velocity ratios -Grade stenosis Pulsatility index - (S-D)/M Resistance index - (S-D)/S Acceleration time - Time from start of systole to peak velocity Indices used to infer status of upstream and downstream vessels

Answer 14

Spectral broadening Turbulence Increased velocities Decreased velocities Damped flow Resistance changes Other waveform changes

Answer 15

Patient supine and rested Acquire spectral waveforms from the CFA, POPA, PTA & ATA Compare each waveform with normal and with proximal waveform Infer disease status in each arterial segment Classify as normal, mild, moderate, severe, blocked Perform ABPI

Answer 16

Imaging & visualisation of disease Use B-mode (greyscale), colour and spectral Doppler and possibly power Doppler Identify low-grade and diffuse disease Interrogate severe lesions to assess degree of stenosis Identify site and length of occlusions

Answer 17

Patient rested and supine with access to the legs (+/- abdomen). Scan the vessels fully in longitudinal section using all modes (heel-toe to optimise angles). Use spectral Doppler to interrogate focal lesions. Identify blocks Assess collaterals

Answer 18

Aorto-iliac segment Supine, occasionally lateral decubitus Femoral Supine, legs externally rotated Popliteal Lateral decubitus or supine Tibials Supine with knee bent / lateral decubitus

Answer 19

Low grade disease Plaque evident. Velocities less than double proximal vessel 50% Stenosis Velocities more than double proximal vessel 75% Stenosis Ratios usually >4 fold increase for LL.

Answer 20

Occlusion -No flow Thrombus -Usually non / low-grade echogenicity (same as blood) Other

Answer 21

Gives reproducible and quantitative measure of disease severity. Results independent of systemic BP. Can be done segmentally Normally ankle pressure should be roughly the same as brachial pressure Significant lower limb arterial disease causes a drop in distal pressure

Answer 22

ankle systolic pressure/ brachial systolic pressure mmHg (units cancels out)

Answer 23

Explain test – will feel tight History & consent Patient should be rested supine (10 minutes) Position is important – brachial and ankle vessels should be at level of heart Use cling-film if necessary to cover ulcers Infection control – clean cuff and probe between patients Risk assessment – DVT, distal graft

Answer 24

Put blood pressure cuffs around BOTH upper arms and both ankles. Cuff width > limb diameter Record systolic BP in BOTH brachial arteries Identify signal with HHD and note waveform Inflate cuff until signal disappears (taking care to remain over artery) Inflate the cuff 20-30mmHg further Slowly reduced the pressure until the signal returns – that is the systolic pressure Record systolic BP in the PT and DP/ATA arteries in both ankles

Answer 25

Continuous-wave Doppler (Hand-held Doppler) – 8MHz Assess the strength and waveform of the posterior tibial artery (PTA) and the anterior tibial artery (ATA) on each ankle. Place the probe directly above the vessel at a 45-60 degree angle (towards the heart) to the skin surface. Use slow movements to identify the area where the signal is loudest then make adjustments to the angle to achieve the optimum Doppler signal. Divide each ankle reading by the HIGHEST brachial reading. Normally the ankle pressure should be approx equal to or slightly higher than the brachial pressure. The lower the ABPI the more severe the disease. Higher values than expected suggest calcified vessels. DIABETICS!!

Answer 26

> 1.2 Calcification may be present >1.0 Probably no arterial disease 1.00-0.81 No significant arterial disease or mild/insig disease 0.80-0.5 Mode disease <0.5 Severe disease <0.3 Critical ischaemia

Answer 27

Probe movement Room temperature Arterial / venous signal confusion Ulceration / gangrene / oedema / obesity R/L brachial asymmetry Calcification Cardiac arrhythmia Cuff size (too small  falsely high, too large  falsely low)

Answer 28

Useful in cases of vessel calcification (diabetics) or venous ulcers / gangrene Digital vessels generally spared from disease Feet must be warm to avoid vasoconstriction Photoplethysmography usually used Normal index >0.65 Absolute pressure of <33mmHg suggestive of CLI

Answer 29

Useful if a good history of claudication but normal resting CW study. Exercise the patient for a set time or until pain occurs. Immediately repeat ABPI measurements. A significant reduction (≥20mmHg) in ABPI indicates haemodynamically significant disease Treadmill Reproducible program Corridor walk Steps / stairs Tip-toes / foot-flex Ergometer (bike/rower) Reactive Hyperaemia

Answer 30

Diabetic PAD is an occlusive arterial disease, affecting distal vessels below the knee. Diabetes augments the process of atherosclerosis through a variety of ways (hypoglycaemia and insulin resistance contribute to endothelial dysfunction by decreasing NO bioavailability and altering the fn of various cell mediators. Oxidative stress therefore promotes the formation of foam cells and fatty streaks. Additionally vascular smooth muscle cells migrate to newly formed lesions, further augmenting plaque development. In advanced atherosclerosis pts with diabetes have less smooth muscle cells in lesions and are more susceptible to plaque rupture than in earlier stages of atherosclerosis. Furthermore, increased platelet aggregation and impaired firbinolaysis also increases risk of thrombosis, therefore pt is high risk for complications. Diabetic patients at higher risk for PAD, with symptoms such as claudication, CLI, and lower extremity amputation

Answer 31

if causing symptoms ro progressing to dangerous level and need more than medial control; standard is bypass - taking tube (vein from leg or synthetic) to connect above and below area of blockage, getting blood downstream to where it is needed in the leg or foot. Endovascular techniques (avoid surgery) - transposing and sending wire through clogged up material, balloon inflated in area of obstruction to squeeze plaque aside and opens vessel. Stent is put in to restore potency of vessel. Can use suction to suck out plaque via catheter. If plaque is so solid, can use laser to bore a hole in it, to then go to angioplasty. Cryoangioplasty uses liquid nitrogen to freeze plaque and cool down cell types within plaque, prevents restenosis.

Arterial Disease Flashcards

(55 cards)