Quiz 3 Flashcards
Duplex Testing
Direct testing
Can locate focal stenosis
Can NOT evaluate the amount of perfusion(flow to feet)
Limitations due to body habitus
Pressures/Waveforms
Indirect Testing
Can only locate levels of disease
Shows total perfusion including flow from collaterals
Limitations due to calcified vessels & multi-level disease
The reason for vascular symptoms:
they are cause by an area of HYPOTENSION within the limb.
These low pressures are from the presence of occlusive disease & lack of adequate collateral circulation to the affected area. (Bernoulli Effect)
Segmental Pressures
Utilizes the Peak Systolic Pressure (PSP) at different levels to evaluate for pressure gradients. The PSP’s are also divided by a reference pressure (Highest brachial PSP) & create ratios known as Pressure Indices. Always Bilateral
Cuff Sizes
Brachial 12cm
Thigh 12-17 cm
Calf & Ankle 10 cm
“Cuff Artifact”
The width of the cuff should be at least 20% wider than the diameter of the underlying limb. Cuff Artifact is a FALSE abnormally high (cuff is to small) or low (cuff to big) systolic blood pressure reading. More commonly HIGH. Elevated above 1.25*
Toe pressure are usually obtained using a ______ sensor that displays qualitative waveforms.
Photoplethsmography (PPG)
Obtain the segmental pressure of the legs working from _____ to ______.
Distal –> Proximal.
All Doppler signal for this test are obtained using a ____ MHz CWD.
4-8 MHz
Pressure Indices
A way to compare the lower extremity blood pressure to the individuals systemic blood pressure. A ratio obtaied using the limb pressure & dividing them by the higher brachial pressure. High thigh pressures are typically 30 mmHg greater than the brachial with 4 cuff tech. Most utilized is ABI.
Ankle-Brachial Index (ABI)
in a non-diabetic patient a normal ABI is 1.0 or greater. Can be falsely elevated due to calcified media layer of the arteries (diabetic patients). An ABI greater than 1.25 is considered falsely elevated (Cuff Artifact).
Toe-Brachial Index (TBI)
A normal toes pressure is usually 60-80% of the brachial pressure. A normal TBI is .60-.80. Digital arteries are usually spared from calcification there it is the MOST reliable pressure.
ABI Ranges
.8-.55
Likely Claudication.
Foot ulcer healing: Probably to likely
ABI Ranges
.55-.35
Likely Claudication
Rest Pain: Probable
Foot ulcer healing: Unlikely
ABI Ranges
.2 or less
Likely Claudication
Likely Rest Pain
Foot Ulcer Healing: unlikely
Impending Gangrene: Likely