Early results of a prospective trial of spliced vein vs PTFE graft with a distal vein cuff for limbt

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Early results of a prospective trial of spliced
vein vs PTFE graft with a distal vein cuff for
limb-threatening ischaemia
16th June 2003 PRINCE OF WALES HOSPITAL JOURNAL
CLUB
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The Question

• Case Study
• Limb-threatening ischaemia
• Distal (below knee) arterial bypass needed
• LSV unavailable for use
• Options
• Synthetic graft /- vein cuff /- distal AVF
• Spliced vein graft
• Composite graft
• Distal graft origin
• What is the best reconstruction option?

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The Answers

• Medline search
• MESH Arterial Occlusive Diseases (18731)
• Femoral Artery (17096)
• and (2811)
• Keywords bypass (791)
• distal or crural (224)
• Limit Human/Abstracts (41)
• English/ gt1995
• Paper Chosen
• Compares Goretex with spliced vein grafting

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Introduction

• Single piece of autologous vein is best
• Unavailable in 50 patients
• Spliced vein bypass grafting
• Constructed joining segments of vein
• 2 year patency rates reported 23-73
• Prosthetic conduit bypass grafting
• Patency
• 30-40 at 3 years
• 60 at 3 years with distal AVF
• 60-79 at 4 years with vein cuff Warfarin
• Hypothesis
• PTFE/Cuff/Warfarin as good as spliced vein

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Patients Methods

• Single centre, prospective, randomised trial
• Inclusion criteria
• Presence of limb threatening ischaemia
• No one piece vein bypass graft option
• Available vein segments for splicing
• No composite sequential bypass option
• Randomisation into 2 groups
• PTFE Group
• Spliced Vein Group

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Patients Methods

• Spliced vein group
• Vein selection on basis of preop Duplex
• Proximal anastomosis prior to further harvest
• 2-3 end-end anastomoses 8/0 prolene
• PTFE graft group
• Venous boot constructed at distal end
• All patients Warfarinised long term

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The Venous Boot (Tyrell Wolfe 1991)
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Monitoring

• Intra/Perioperative
• Physical examination Doppler
• Completion angiography
• Ward protocols
• Medium/Long term
• Physical examination Duplex scanning
• At 1/3/6/9/12 months then 6-monthly

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Results

• Between 1996-2000
• 39 bypass grafts in 36 patients recruited
• 20 PTFE
• 19 Spliced vein
• Randomisation process
• Equivalent
• Age/sex/ABPI/DM/Smoking/Previous grafts
• Non-equivalent
• Significantly higher cardiac risk status in
  spliced vein group (Plt.0001)

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39 Grafts
20 PTFE/Cuff Group
19 Spliced Vein Group
Inflow Artery Graft/Iliac 5 (25) CFA
15 (75)
Inflow Artery Graft/Iliac 2(10) CFA 10
(53) SFA 4 (21) PFA 3 (16)
Outflow Artery Pop 4 (20) AT 6 (30) Per 6
(30) PT 4 (20) DP 0 (0)
Outflow Artery Pop 4 (21) AT 1 (5) Per 8
(42) PT 3 (16) DP 3 (16)
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Perioperative Statistics

• Cardiac bleeding complications were more
  frequent severe in the spliced group

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Long term Statistics

• Note 1 patient in the PTFE/Cuff group lost to
  follow up
• 4/10 PTFE/Cuff failures were associated with
  cessation of Warfarin therapy

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Study Conclusions

• Spliced vein reconstruction
• Increased morbidity/mortality
• Increased need for revision
• Trend for superior patency rates
• PTFE/Cuff reconstruction
• Aggressive anticoagulation therapy needed
• 4/10 PTFE failures because Warfarin ceased
• Primary patency _at_ 2years with Warfarin 71
• Less time, less blood loss shorter stay
• ??Less risk in morbidity/mortality

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Study Strengths

• Prospective, randomised trial
• Well defined entry criteria
• Good patient follow up
• Objective measurement of outcome
• Applicable to clinical practice

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Study Weaknesses

• Small sample size
• Unequal randomisation
• Cardiac risks (higher in spliced group)
• Increased morbidity/mortality
• Most distal bypasses (DP) all in spliced group
• All inframalleolar bypasses
• Statistically,
• Increased probability of a type II error
• Low Power study

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Study Weaknesses

• No controls
• Particularly relevant wrt to limb salvage
• Unclear information
• Process of randomisation
• Monitoring of Warfarin therapy in PTFE group

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