Dialysis Access Ultrasound Evaluations. BILLY ZANG BS RVT RDMS FSVU 12th Annual Vascular Innovations Conference FEBRUARY 6-7, 2015

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1 Dialysis Access Ultrasound Evaluations BILLY ZANG BS RVT RDMS FSVU 12th Annual Vascular Innovations Conference FEBRUARY 6-7, 2015

2 Disclosure Employee of GE Healthcare The opinions and teaching points made during this lecture are made by Billy Zang with no influence or direction from GE Healthcare.

3 SVU PROFESSIONAL PERFORMANCE DVD SERIES

4 RENAL INSUFFICIENCY ~300,000 patients in the U.S. are on hemodialysis Medicare expenditures are over $2 billion/year Average cost per patient/year exceeds $50,000 Most of that money is spent on hemodialysis access Rodin

5 HEMODIALYSIS ACCESS Dialysis of soluble substances and water from blood by diffusion through a semipermeable membrane renalweb/imstaff/line.jpg Must be durable - to withstand repeat punctures

6 TYPES OF DIALYSIS ACCESS Silastic, Double-lumen, Cuffed Tunneled Catheters Can be used immediately after placement Primarily used as intermediate-duration vascular access to allow maturation of endogenous fistulas Provide acceptable long-term access in patients who have exhausted all available sites Are inferior to AV access as long-term access, since they provide lower flows and have higher rates of infection and other complications.

7 TYPES OF DIALYSIS ACCESS Synthetic AV access (bridge grafts) AV fistulas constructed with synthetic material, most commonly polytetrafluoroethylene (PTFE) Provides excellent vascular access in patients who fail endogenous AV fistula placement PTFE has good surgical handling characteristics, and grafts of this material usually mature in two weeks Synthetic grafts have a higher long-term complication rate than primary fistulas.

8 TYPES OF DIALYSIS ACCESS Primary AV Fistulas Brescia-Cimino Fistula Preferred form of vascular access Typically constructed with an end-toside vein-to-artery anastomosis of the cephalic vein and the radial artery These fistulas have good long-term patency and infrequently develop infectious complications A well constructed radial cephalic fistula that functions for the first six months can be expected to function for up to 20 years

9 The Fistula First Breakthrough Initiative is dedicated to improving care for people with chronic kidney disease by increasing AV fistula placement and use in suitable hemodialysis patients.

10 EVALUATION OF DIALYSIS ACCESS GRAFTS/FISTULAS

11 EVALUATION OF DIALYSIS EXAMINATION PROCEDURE B-MODE Use both transverse and longitudinal views Evaluate for perigraft fluid collection Evaluate for masses Evaluate for intraluminal defects Measurements should be obtained from any area that intraluminal narrowing is suspected AVF grafts will have brightly echogenic double lumen walls

12 EVALUATION OF DIALYSIS Clinical Indications Elevated venous pressure during dialysis Limb swelling Increased recirculation time Decreased thrill or pulse Cold hand or fingers Change in the dialysis performance Difficult cannulations Prolonged clotting of puncture site after dialysis Perigraft masses

13 EVALUATION OF DIALYSIS Assessment of Patient History and physical Type of access Location Date of placement Copy of OP report Previous line placements Previous dialysis problems Note any arm swelling or prominent venous collaterals along the chest wall Feel for palpable thrill

14 EVALUATION OF DIALYSIS Equipment Any commercially available color duplex imager High frequency ultrasound transducers 5.0, 7.5, or 10MHZ Acoustic coupling gel Standoff pad can be useful Continuous wave Doppler, PPG sensor and digital pressure cuffs

15 EVALUATION OF DIALYSIS EXAMINATION PROCEDURE Spectral Analysis Evaluation should include arterial inflow, graft or fistula and venous outflow through subclavian vein Maintain <60 degree angle Note appropriate direction of flow Typically graft flow is turbulent Increased spectral broadening is usually noted

16 EVALUATION OF DIALYSIS Arterial Limb High velocity Continuous forward flow Marked spectral broadening

17 Venous Limb EVALUATION OF DIALYSIS Lower velocities than arterial limb Most common site of obstruction

18 EVALUATION OF DIALYSIS Diagnostic Criteria Normal Arterial side PSV range from cm/s EDV range from cm/s Venous side Examination Procedure PSV range from cm/s Will still exhibit arterial pulsations

19 EVALUATION OF DIALYSIS Diagnostic Criteria Abnormal Arterial side Stenosis of the arterial anastomosis is infrequent< 15 % of all graft failures Venous side Examination Procedure Stenosis at the venous anastomosis is the most common cause of graft thrombosis A focal > 100% increase in velocity compared to the more proximal segment usually = a flow reducing stenosis

20 EVALUATION OF DIALYSIS Duplex Scanning Limitations Severe edema Precise measurement of percent stenosis and volume flow Numerous graft revisions Painful limb Post op synthetic grafts may not visualize immediately due to air contained within the body of the graft

21 EVALUATION OF DIALYSIS

22 EVALUATION OF DIALYSIS Helpful Hints Increase in venous pressure during dialysis usually = outflow problems High resistant pulsatile waveform within the graft usually = outflow stenosis Low velocities within the graft usually = arterial inflow problems A focal > 100% increase in velocity compared to the more proximal segment usually = a flow reducing stenosis

23 EVALUATION OF DIALYSIS Grafts in Jeopardy of Failure A peak systolic velocity < 150 cm/s A high resistance signals in the proximal graft. Flow volumes Functional disorder: ml/min (fistulagram warranted) Impending failure: < 500 ml/min (poor outcomes) High cardiac output failure: >2500 ml/min

24 THANK YOU Billy Zang