sensitivity of duplex ultrasound in evaluation of av access with comparison to digital substraction...

Sensitivity of duplex ultrasound in

evaluation of AV access with comparison to

digital substraction angiography

Department of Surgery, College of Medicine and Health Sciences, UAE University, Al- Ain, UAE.

Ali Jawas, Mohammed Murtuza, Trab Manar, Safi Basel, Fikri Abu-Zidan

Maintenance of AV access is essential for

patients on hemodialysis.

Monitoring of the access helps to detect stenosis

prior to complete occlusion.

Endovascular intervention for failing vascular

access could prolong the patency of the access.

Introduction

The gold standard to diagnose stenosis of AVF and

AVG is angiogram.

Duplex scan is non invasive, less expensive and

widely used for various vascular conditions.

Currently there are no well-defined

ultrasonographic criteria for evaluation of AVF

and AVG.

Many apply the duplex criteria of arterial

stenosis.

Introduction

To report on the Value and sensitivity of

duplex ultrasound for evaluation of AV

access with comparison to digital

substraction angiography

Objectives

• 121 patients were referred to our vascular laboratory

for evaluation of AV fistulas and AV grafts over 9

months (January 2013 to September 2013) .

Patients and methods

Tawam Hospital Al-Ain Hospital

• GE Logic 9 Duplex scanner with linear broadband

transducers of 12 MHz and 7 MHz for superficial and

deep vessels respectively.

Patients and methods

1. Reduced thrill or weak bruit on auscultation

2. Decrease dialysis flow rate. (KDOQI)

3. High venous pressure. (KDOQI)

4. Difficulty in access cannulation.

5. Excess post dialysis bleeding.

Criteria for referral for access duplex ultrasound

• Peak Systolic Velocity of >400 cm/sec.

• Peak Systolic Velocity Ratio >3.5 (between

the area of stenosis and pre-stenosis).

• Luminal narrowing on B mode image.

• Volume flow <400

Critical stenosis parameters and Endpoints

• Moderate stenosis Peak Systolic Velocity

Ratio (3.5-2), Volume flow (400-600)

• Mild stenosis Peak Systolic Velocity Ratio

<2, Volume flow (>600).

Stenosis parameters and Endpoints

• Anastomotic stenosis (at the anastomosis of

fistula or graft).

• Junctional stenosis (at the junction of

cephalic and subclavian veins).

• Venous outflow stenosis (stenosis in the

outflow vein or graft).

Location of Stenosis

• Angiography was performed on all hemodynamically

significant stenosis diagnosed by Duplex scan.

• Percentage stenosis in angiogram was calculated by

measuring the stenotic vessel diameter in comparison

to pre- and post stenotic vessel.

• Angioplasty performed in the same setting if

significant lesion is confirmed on angiogram.

Angiography

Mean age (SD)

56.6 (17.3) years

Results

Male = 78 (64 %)

Female = 43 (36 %)

Type Number %

Normal 29 24%

Mild stenosis 12 9.9%

Moderate stenosis 19 15.7%

Severe stenosis 49 40.5%

Occlusion 12 9.9%

Total 121 100

Results

Normal Mild Moderate Severe

Kruskall Wallis test p < 0.0001

Normal Mild Moderate Severe

Kruskall Wallis test p < 0.0001

Normal Mild Moderate Severe

Kruskall Wallis test p < 0.0001

Site of stenosis Mild Moderate Severe Total

Anastomotic 12 (100%) 17 (89.5%) 40 (81.6 %) 69 (86.3%)

Junctional 0 (0%) 2 (10.5%) 7 (14.2%) 9 (11.3)

Venous outflow 0 (0%) 0 (0%) 2 (4%) 2 (2.5 %)

Total 12 (100%) 19 (100%) 49 80 (100 %)

Results

P = 0.64 , Fisher’s Exact test

121 patients

Complete

occlusion

12

Mild-

moderate

Stenosis

31

Follow up

Severe

Stenosis

49

Angiography

Normal

29

46

44 (95.6 %)

Severe stenosis

Sensitivity

95.6 %

Pre-angioplasty

Post Angioplasty

• Ultrasound is a sensitive screening tool for

guiding decisions on interventions for vascular

accesses.

• Vascular laboratory and good vascular

technologist is an essential and important

service in the evaluation and management of

vascular access.

Conclusions

College of Medicine and Health Sciences,

UAE University