Catheter Tip Design. Disclosure. In Vitro Performance of Long-Term Hemodialysis Catheters. ASDIN 10th Annual Scientific Meeting Final

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1 In Vitro Performance of Long-Term Catheters Disclosure for Thomas Vesely, MD Thomas M. Vesely, MD Saint Louis, Missouri Adrian Ravenscroft Phase One Medical Hingham, Massachusetts Phase One Medical Consultant Caymus Medical Advisor Cylerus Consultant W. L. Gore & Associates Consultant Does tip design affect the performance of a hemodialysis catheter? Recirculation Tip stability Blood flow turbulence Step-tip Split-tip Catheter Tip Design Separation of Inflow from Outflow Tip Design to Decrease Recirculation Inflow into arterial lumen Direction of blood flow in superior vena cava Outflow jet from venous lumen 1

2 Symmetric tip design Decreases recirculation if blood lines are connected in reverse configuration Specific Features of Catheter Tip Design Description of Catheters Name Size Length Tip Design A/V Offset Sideholes Split Length ProGlide cm step 30mm yes Titan cm step 25mm yes Ultrastream cm step 20mm yes 14 28cm split 30mm yes 80mm Centros 15 24cm split 25mm no 25mm Hemosplit XK 16 23cm split 30mm yes 45mm Equistream 16 27cm split 12mm yes 43mm Palindrome cm symmetrical 11.5mm yes Symetrex cm symmetrical 8.5mm no 30mm 25mm 20mm ProGlide Titan Ultrastream A/V offset of step tip catheters 45mm 80mm 25mm 30mm 30mm 25mm 11.5mm 8.5mm Hemosplit XK Centros Palindrome Symetrex Split length and A/V offset of split tip catheters A/V offset of symmetrical catheters 2

3 Flow Barriers thick horizontal flow barrier thin vertical barrier separates midline of arterial end hole Side holes : Location Size & Shape Number Beveled tip ProGlide Ultrastream In Vitro Test System 3 independent circuits 3 - circuits 3 - peristaltic pumps 6 - air actuated valves SVC = 2400ml/min Venous lumen = 425ml/min Arterial lumen = 425ml/min Vertical glass column simulated SVC 24mm x 350mm Rate of blood flow through SVC = 2400ml/min Catheter tip positioned in observation zone Viscosity of Test Fluid Hematocrit (%) Viscosity (cp) (plasma) The ICU Book 3 rd Edition centipoise = water 2.3 centipoise = blood with hematocrit = 40% - no cellular components of blood 3

4 Measurement of Recirculation Catheter Testing Protocol Serial dilution of blue dye used for colorimetric calibration dual channel optical sensor calibrated for 620nm and 800nm Measurement of recirculation using indicator dye method % recirculation correlated to absorption of blue dye aspirated into inflow (arterial) lumen The 9 hemodialysis catheters underwent 72 testing procedures Each catheter was tested four times at each viscosity: - twice with blood lines in standard configuration - twice with blood lines in reverse configuration Results Equistream Standard configuration Arterial limb = inflow Venous limb = outflow Equistream Reverse configuration Venous limb = inflow Arterial limb = outflow Recirculation None of the 9 catheters had recirculation with blood lines connected in standard configuration at both 1.0cP and 2.3cP fluid viscosity (water) (40% Hct) With blood lines in reversed configuration catheter tip design affected the rate of recirculation 4

5 Catheter flow rate = 425ml/min Reversed blood lines Hemosplit Reversed blood lines SVC flow rate = 2400ml/min jet of blood flow directed into inflow lumen inflow lumen 39% recirculation jet of blood flow directed into inflow lumen venous end hole inflow lumen 33% recirculation Centros Reversed configuration jet of blood flow directed into inflow lumen inflow lumen Palindrome 0% recirculation with standard and reverse blood lines 22% recirculation Standard configuration Reversed configuration Recirculation Rates with Reversed Blood Lines Type Name Recirculation Observations 5

6 Standard blood lines Standard blood lines jet of fluid pushes catheter catheter tip moves against wall of SVC Hemosplit XK Hemosplit XK No movement of catheter tip with standard blood lines With reversed blood lines there is significant (3+) movement of catheter tip Catheter flow rate = 425ml/min Aspiration caused venous end hole to adhere to SVC wall stagnant blood between lumens stagnant blood between lumens Hemosplit XK Reverse blood lines Reversed blood lines 6

7 Split tip Step tip Symmetric tip Thrombus can develop on any catheter tip Summary Currently available hemodialysis catheters have no significant recirculation when connected in the standard configuration Split tip-type catheters have >20% recirculation when connected with reversed blood lines Catheter tip design influences catheter stability and the development of catheter tip thrombus 7