Central venous catheter design and adequacy of hemodialysis - - PowerPoint PPT Presentation

Maurizio Gallieni

Nephrology and Dialysis Unit Ospedale S. Carlo Borromeo, ASST Santi Paolo e Carlo, University of Milano, Milano, Italy

September 14, 2018 - Paris

Central venous catheter design and adequacy

• f hemodialysis

Natalie Cole holds a Grammy February 8, 2009

Photo: Macon/Getty

May 2009 31 Dec 2015

Characteristics of the ideal dialysis catheter

• Easy to insert and remove
• Kinking resistant material
• Free of infection
• Free of fibrin sheath (invisible to body)
• Does not cause venous thrombosis and/or stenosis
• Delivers high blood flow (> 400 ml/min), reliably
• No recirculation
• Durable
• Comfortable and acceptable to the patient
• Inexpensive

Modified from: Trerotola SO. Radiology 2000; 215:651-658

Poiseuille’s law

Catheter Diameter and Performance

Changes in the radius (and therefore in diameter) potently influence blood flow (Q)

Increasing the diameter from 2.0 to 2.1 mm will increase blood flow by 20% 20% diameter increase: 2X increase in flow 50% diameter increase: 5X increase in flow 100% diameter increase:16X increase in flow

If CVC length is doubled, flow will be reduced by 50%

Cuff Split tip Pre-curved

Non-tunnelled vs tunnelled catheters

(acute vs chronic)

Acute dialysis catheter design

Internal jugular vein Femoral (and subclavian) vein

Pre-curved

Internal jugular vein

Valved introducer vs over the wire insertion

Mojibian H. J Vasc Access 2010; 11: 342-45

Retrograde vs. antegrade tunneling

Retrograde tunneling and catheter

Retrograde vs. antegrade tunneling

Antegrade tunneling

Single lumen vs double lumen catheters Tunneled catheter design

Catheter tip design Side holes versus no side holes

Catheter tip design Split tip, step tip, symmetric tip

Self flushing functional tip

Spector J Vasc Interv Radiol 2008; The symmetric tip design theoretically allows flow of blood through the catheter tip between treatments. The blood enters through the side slots and exits through the tip. This flow of blood might reduce thrombus formation on the catheter tip.

Catheter tip design Pre-shaped, reversed ports

Review of the general features of CVCs, including differences between tunneled and nontunneled CVCs, materials and their compatibility with lock solutions, the implications of straight versus precurved design in nontunneled CVCs, lumen and tip features with their clinical implications, catheter coatings and their effect on infection and thrombosis.

NDT 1998; 13: 745-9

• The PermCathTM and TesioTM provide blood flow and

reliability superior to the VasCathTM.

• All three catheters are capable of providing adequate

haemodialysis although large patients will need extended treatment times.

• Blood flow is limited in all catheters by inflow, as

evidenced by negative arterial pressure.

• All catheters had acceptable recirculation.
• AV access is superior in terms of blood flow and

reliability to all tested catheters.

Kidney International, 2002; 62: 282–289

• Prospective, randomized trial comparing the Ash-

Split (MedComp) and Opti-Flow step tip (Bard Access Systems) hemodialysis catheters.

• The purpose was to compare the function and

complications of the two catheters

Trerotola S et al. Kidney International, 2002; 62: 282–289

• 132 patients were enrolled in the trial.
• Maximal blood flows were 414 mL/min for the split tip

and 433 mL/min for the step tip (P = 0.03)

• Recirculation was significantly higher with the step tip

catheter (7.9% vs. 1.6% at 400 ml/min).

• Total late complications were lower the split tip group

(25% vs 42.6%, P = 0.04), and catheter survival (figure next slide) was significantly higher in the split tip group (P 0.02).

RESULTS

Trerotola S et al. Kidney International, 2002; 62: 282–289

Split tip Step tip

+ ++ +++ + + + + + + + + + + + + + + + +++ + + + + + + + + + + +

CVC survival - Log-rank test P = 0.022

JVIR 2008

Case-control study

Kakkos SK et al. JVIR 2008

Primary assisted patency rates – Overall results

Am J Kidney Dis. 2014; 64:902-908.

HemoStar step tip

Palindrome Symmetric Tip

302 CVCs in 239 patients

Van der Meersch H et al. AJKD 2014; 64:902-908

Van der Meersch H et al. AJKD 2014; 64:902-908

Van der Meersch H et al. AJKD 2014; 64:902-908

Van der Meersch H et al. AJKD 2014; 64:902-908

• Urokinase use was lower (-42%) and blood flow rates

were higher (+9%) for the Palindrome catheter

• Catheter survival was excellent for both catheters (71.3%

for Palindrome and 76.4% for HemoStar at 24 months)

• Removal for thrombosis and infection were very low

compared with data in the literature and were similar for both catheters.

CONCLUSIONS

Prospective, observational cohort study comparing the function and complication rates of tunneled CVCs in dialysis patients within a follow-up period of 24 months.

• 1. Shotgun (SG) modified step-tip
• 2. Split-tip (ST)

Thrombolytic therapy with alteplase was used significantly more often in the Split-tip (ST) group (29%) than in the Step-tip (SG) group (16%). The CVC replacement rate was significantly higher in the ST group (19.3%) compared with the SG group (8.7%).

Observational study in 73 patients (46 self-centering vs 27 slpit-tip).

• Improved patency with the self-

centering catheter versus the split-tip catheter.

• Mean blood flow at 6 mo: 388 vs 352

ml/min (p<0.01).

self-centering split-tip

Observational study in 46 patients.

• Mean blood flow 333-392 ml/min.
• Kt/V > 1.5
• Two infections: 0.7/1000 CVC days

CONCLUSIONS

• Catheter design does have an impact on performance
• More design improvements are desirable, to move towards

the “perfect” CVC, invisible to the body (no thrombosis), with no or very low infections, patient friendly.

• Such a CVC could solve one of the major obstacles to the

development of home hemodialysis