1. Diagnostic Medical Sonography Program
Lecture 21: Miscellaneous Conditions, Diagnostic Tests, and Treatment
Holdorf

2. Arterial Miscellaneous Conditions, Diagnostic Tests, and Treatments
Condition: Subclavian Steal
Subclavian occlusion results in retrograde flow in ipsilateral vertebral artery.
Alternating flow usually correlated with angiographic evidence of high-grade subclavian stenosis
Patients with subclavian occlusion are usually asymptomatic: are claudication is rare

3. May have blood pressure difference of > 15-20 mmHg; may have decreased pulses in affected arm.
Ipsilateral vertebral artery feeding high-resistance vascular bed
Surgical treatment may include a bypass graft or endarterectomy

4. Subclavian Steal

5. Condition: Temporal arteritis
Inflammation of the arterial wall of the superficial temporal artery or its front and or parietal branches
Inflamed arterial segments often larger in diameter with homogeneous thickening evident on B-mode
An anechoic HALO from edema of the intima may be seen
Intimal thickening may result in significant stenosis where PSVs are doubled

6. Superficial Temporal Artery Terminal branch of the ECA Ascends in front of ear – where it is palpable

7. Temporal arteritis

8. Miscellaneous Diagnostic Tests
Arteriography:
Interpretation
Normal anatomy should be visualized
Abnormalities include:
Filling defect
Absent vessel
Aberrant anatomy
Percent stenosis calculated

9. Normal Anatomy

10. Filling Defect

11. Example for calculating Diameter Reduction Diameter reduction: D = 8mm, d = 2mm 1 – (d/D) x 100 = 1 – (2/8) x 100 = 1 – (.25) x = .75 x 100 = 75%

12. What is an Endarterectomy?
Calculated % stenosis based on NASCET study: North American Symptomatic Carotid Endarterectomy Trial
What is an Endarterectomy?
Surgical removal of part of the inner lining of an artery, together with any obstructive deposits, most often carried out on the carotid artery or on vessels supplying the legs.
The North American Symptomatic Carotid Endarterectomy Trial (NASCET) demonstrated a conclusive benefit for carotid endarterectomy in patients with symptomatic 70-99% ICA stenosis.

13. MR Angiography
Extremely sensitive to the presence of stenosis, but tends to overestimate the disease process
May be used when a carotid duplex study is equivocal or technically limited CT
Most frequent application in cerebrovascular disease: evaluate the nature of cerebral infarctions, intracranial aneurysms, hemorrhage and AVMs

14. Treatments Medical Lifestyle modifications Pharmacological
Stop smoking
Weight control and low cholesterol diet
Pharmacological
Aspirin: an anti-platelet drug that decreases platelet aggregation resulting in decreased thrombotic activity

15. Treatments
Surgical
Stenosis: Endarterectomy: Surgical removal of atherosclerotic material
Occlusion: Usually receives no surgical intervention

16. Treatments Endovascular (Stent)
Designed to maintain the intraluminal structure and patency of the artery; acts as a type of “scaffold”
Increasing use of stents in carotid artery stenosis: may expect some flow acceleration post-stenting

18. Additional Notes
Miscellaneous- conditions, diagnostic tests, and treatment
Subclavian steal
In the vertebral artery, demonstrates alternating “Too-Fro” flow velocities (high systolic component – positive- component, and a very low – below the baseline, diastolic component.

19. Normally, the vertebral artery demonstrates low resistance flow velocity.
Proximal occlusion: proximal to the ipsilateral vertebral artery. Blood is not getting to the distal arm, so the vertebral artery “saves the day” by supplying the blood, hence reversal of blood flow.
Temporal arteritis
Will see an inflammation HALO
No Biopsy for this.

20. NASCET study – North American Symptomatic Carotid Endarterectomy trial
Treatment of choice for significant Carotid stenosis or occlusion is the Endarterectomy, which completely removes the plaque.
Take the distal CCA diameter that is free of stenosis example 5cm
Take the diameter that is open between the stenosis example 2cm
Divide the smaller number by the bigger number
1 – (2/5) x 100 = 40 – x 100 = 60% diameter reduction.
Treatment-
Endovascular stent
Expect FAST FLOW through the stent.
If getting 125 cm/sec, then this is abnormal.
Expect very high numbers: example: 400 cm/sec.

21. Homework Textbook: Chapter 22: Atypical Vascular Disorders
Chapter 23: Alternative Diagnostic Tests and Therapeutic Interventions
Pages: 249 – 262
SDMS Assignments