CASES 929-930: AVF ULTRASOUND EVALUATI, Dr PHAN THANH HẢI, Dr PHAN THANH HẢI PHƯỢNG, MEDIC MEDICAL CENTER, HCMC VIETNAM.

 By the two cases of vessel obstacles of AVF for renal hemodialysis.

Indications for AVI Doppler Ultrasound Examination

Pre-operative vascular examination of the arm to create arteriovenous anastomosis. Assess good shunt/graft maturity after 4-6 weeks. Assess complications when AVF function is abnormal: (1)

• Difficulty inserting the cannula

 • Blood clot detected during aspiration

Venous pressure greater than 200 mmHg or 300 cc/minute/pump

Increased RT >15 %

• Decreased blood urea rate <60% Suggestions for abnormal functional AVF: (2) 

• Collapsed inlet suggested by low arterial flow

• Poorly mature AVF

 • Loss of palpation 

• Distal extremity ischemia 

• Skin/soft tissue infection

• Aneurysm/pseudoaneurysm around the graft/needle insertion site

CASE 1  

• Female patient, 39 year-old

• Ultrasound examination of left arm AVF suspected

suspected blockage

• The patient is painless and has no unusual symptoms.

O

Ultrasound examination of left arm AVF:

AVF of the brachial artery and cephalic vein: AVF: Calcified plaques causing 30-40% stenosis, inner diameter = 4.5 mm, biphasic spectrum, flow velocity = 99 ml/min. Several stenotic segments of the vein are calcified, causing a significant reduction in flow after stenosis. From the middle half of the arm to the shoulder, 90% stenosis and near occlusion are present. Fibrosis and collapse of the short confluence segment.

Case 2:

• Male patient, 62 year-old

•Ultrasound examination of AVF 2025. Patient

with cephalic vein stenosis causing venous thrombosis has undergone angioplasty and thrombectomy.

Post repaired 

.

 

Lessons learned

• Discuss with the Clinical Physician: PTV/Interventional Vascular Surgeon to address the root cause of the problem.

• When there is widespread thrombosis: locate the highest possible stenosis and combine with contrast-enhanced CT to assess blind spots. • For calcified blood vessels, SMI assists in accurately assessing the thrombus and differentiating from atherosclerotic stenosis from collapse after thrombosis.

• Always review previous results.

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