Title:
Stenosis detection in failing hemodialysis access fistulas and grafts: comparison of Color Doppler Ultrasonography, Contrast-Enhanced Magnetic Resonance Angiography and Digital Subtraction Angiography

Cornelis Doelman¹ ;Cornelis Doelman¹ ;Cornelis Doelman² ;Cornelis Doelman¹ ;Cornelis Doelman¹ ;Cornelis Doelman¹ ;Cornelis Doelman³ ;Cornelis Doelman⁴ ;Cornelis Doelman³ ;Cornelis Doelman¹

Michelangelolaan 2 PO Box 1738 Michelangelolaan 2 Michelangelolaan 2

E-mail address corresponding author:
LEMDuijm@hotmail.com

Background:
Several imaging modalities are available for the evaluation of dysfunctional hemodialysis shunts. Color doppler ultrasonograhy (CDUS) and digital subtraction angiography (DSA) are most widely used for the detection of access stenoses and contrast-enhanced magnetic resonance angiography (CE-MRA) of shunts has recently been introduced. To date no study has compared the value of these three modalities for stenosis detection in dysfunctional shunts. We prospectively compared CDUS and CE-MRA with DSA for the detection of significant (>50%) stenoses in failing dialysis accesses and we determined whether the interventionalist would benefit of CDUS performed prior to DSA and endovascular intervention.

Methods:
CDUS, CE-MRA and DSA were performed of 49 dysfunctional hemodialysis arteriovenous fistulas (AVFs) and 32 grafts (AVGs). The vascular tree of the accesses was divided into between three and eight segments depending on access type (AVF or AVG) and length of venous outflow. CDUS was performed and assessed by a vascular technician, while CE-MRA and DSA were interpreted by two MR radiologists and two interventional radiologists, respectively. All readers were blinded to information from each other and from other studies. DSA was used as reference standard for stenosis detection.

Results:
DSA detected 111 significant (>50%) stenoses in 433 vascular segments. Sensitivity, specificity, and positive and negative predictive value of CDUS versus CE-MRA in detection of vessel segments with significant stenoses were 91% (95%CI 84-95%) vs. 96% (95%CI 90-98%), 97% (95%CI 94-98%) vs. 98% (95%CI 96-99%), 91% (95%CI 84-95%) vs. 94% (95%CI 88-97%) and 97% (95%CI 94-98%) vs. 98% (95%CI 96-99%), respectively. CDUS and CE-MRA depicted respectively three and four significant stenoses in six non-diagnostic DSA segments. The interventionalist would have chosen an alternative cannulation site in 38% of patients if the CDUS results had been available.

Conclusion:
We suggest that CDUS be used as initial imaging modality of dysfunctional shunts, but complete access should be depicted at DSA and angioplasty in order to detect all significant stenoses eligible for intervention. CE-MRA should be considered only if DSA is inconclusive.

Subject:
Vascular Access

Back