Transcript APSIR-dialysis 2004

Balloon Angioplasty for Low Flow Access
Dheeraj K. Rajan MD,
FRCPC, FSIR
Division of Vascular and Interventional
Radiology
University of Toronto – University Health
Network
Angioplasty – The Gold Standard
• Goal is to relieve the stenosis
• Venous stenoses associated with dialysis
access is typically unyielding often
requiring high pressure balloons
• Following PTA, recurs in a short period of
time
• Complications of PTA
Patch Angioplasty is Surgery
Balloon versus patch angioplasty as an adjuvant Tx to
surgical thrombectomy of hemodialysis grafts.
• Case control study of PTA and patch angioplasty
pts
• RESULTS: 10 patencies of patch & PTA group:
86% vs 77% at 1 mo, 45% vs 40% at 3 mos,
17% vs 28% at 6 mos
• No statistically signif diff btw the 2 groups
• CONCLUSION: Balloon angioplasty offers
advantages to patch angioplasty, with similar
patency rates. We recommend balloon angioplasty
as a comparable method to salvage dialysis access
grafts
• DOQI guideline  percutaneous
Bitar G et al. Am J Surg 1997;174:140-2.
Slide courtesy of Ziv Haskal
Angioplasty
• The potential long-term patency rate following
PTA is (possibly) well established.
• Published series consistently report 40% to
50% 6-month unassisted patency rates from
PTA. Long-term unassisted patency after
surgical revision is less well established due to
reporting of cumulative patency.
Prospective
AVG 10 Patency after PTA
38-63% 6 mo. (retrospective series)
23-41% 6mo. (prospective series)
Probably more accurate
Levels of evidence: Access Interventions
Slide courtesy Ziv Haskal
Advances – What Advances?
• K/DOQI recommends 50% 6 month
primary patency following angioplasty
• Technical success <30% residual stenosis
• New devices – do they improve patency?
• Is there any value in prophylactic
intervention?
• The future?
PTA Resistant Stenoses
• Lesions resistant to PTA overall 10-15%
– Clark, JVIR 2002; 51
– Rajan, Radiology 2004; 508
• 55% of dialysis stenoses required inflation
pressures > 15 atm when grafts/fistulas were
combined
– Trerotola, JVIR 2005; 1613.
• Lesion most difficult to treat is the cephalic
arch
Patencies
Patency Rates After Percutaneous Angioplasty for Nonthrombosed Autogenous Hemodialysis Fistulas
Fistula
Reference
No. of fistulas
type
*
Success
Primary patency rate, %
Secondary patency rate, %
rate, %
6 mo
12 mo
24 mo
6 mo
12 mo
91
58
44
40
90
85
Manninen et al
Forearm
53
Clark et al
Forearm and
53
94
55
26
82
82
85
81
upper arm
Lay et al
Forearm
31
90
77
54
Turmel-Rodrigues
Forearm
155
95
67
51
37
---
85
Upper arm
65
97
57
35
24
---
82
Forearm
94
98
75
62
88
86
Upper arm
57
overall
51
39
89
85
et al
Rajan et al
*Includes 12 thrombosed fistulas.
Lay JP et al. Clin Radiol 1998; 53:608-611.
Clark TW et al. J Vasc Interv Radiol 2002; 13:51-59.
Manninen HI et al. Radiology 2001; 218:711-718.
Turmel-Rodrigues et al. Nephro Dial Transplant 2000; 15:2029-2036
What else has been tried?
Conquest versus regular PTA
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Grafts
55 PTA’s each group
No difference in patency
Only venous anastomosis grafts
10-20% stenoses require pressure >15 atm
Cutting Balloon Folding Design
• Slow inflation & deflation
• 1ATM every 3-5 sec.
• Atherotomes descend
within the folds of balloon
material
• Minimizes atherotome
exposure to healthy tissue
• Device should not
exceed 10 inflation
/deflation cycles
Cutting Balloon
JVS -2014
• 623 patients – mixed grafts and fistulas
• At venous anastomosis at 6 and 12 months
primary assisted patency significantly better
– 86 vs 63; 56 vs 37%
• Really treatment area primary patency
– Not access circuit or secondary
• Ultrasound follow-up monthly
Cutting Balloon - Again
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Autogenous fistulas
USED if conventional PTA did not work
71/516 randomized to HPTA vs. cPTA
Six month f/u angio
66% versus 40% at 6 months
JVIR 2014; 190
Nitinol Stents
• Since 1991, >10% of PTA procedures associated
with stent placement
• Chan 2008
– 25% versus 3% primary patency 6 mts
– AVG’s
• Retrospective with 64 patients
– Centrally: 14.9 months
• 12 month: 67%
– Mean primary patency peripheral: 8.9 months
• 12 month: 20%
– Almost all were severely stenosed at 6 mts
Vogel, JVIR 2004: p1051-1060
39% 6-month 10 patency for stents
73% 6-month 10 patency for PTA
p = 0.028
Kariya S, et al. Cardiovasc Intervent Radiol
(2009) 32:960–966
Stent Usage
• No definite conferred long term benefit over
PTA
• Can convert focal lesion to lesion length of the
stent
• Used as bailout for:
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Rupture
Reobtruction
Recoil
? rapid recurrence of stenosis (<3 mts K/DOQI)
Novel Technologies
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Cryotherapy
Gene therapy
Drug eluding stents
Brachytherapy
Atherectomy catheters
Dissolving stents
Brachytherapy cont…
Dosing scheme: 18.4 Gray
at 0.5mm into the vein wall
Treatment times: 214 to
323 seconds
Brachytherapy
• Novoste Bravo trial
• Beta radiation source
• Trial cancelled
– Switched study population inclusion criteria part way
through trial
• 42% target lesion primary patency end point at 6
months as compared to 0% of the control group (P
= 0.015) - did not translate into an improvement in
secondary patency at either 6 or 12 months.
• Misra S, KI 2006 (70) p 2006
Cryoplasty
PolarCath System
Nitrous Oxide Coolant
Cryoplasty
• Stenosis or thrombosis increased from 3
weeks to 16 weeks
• Only 5 patients
– Am J Kidney Dis, 2005; 45(2): e27-32.
• 20 patients
– 35% technical success
• 25% 6 month patency
• Associated with severe pain
– Gray JVIR 2008
Atherectomy Devices
• SilverHawk/TurboHawk/DiamondBack
– T – Designed to cut through CTO’s (hard plaque)
– S – Everyday plaque with no thrombus and/or calcified
plaques
– No iliac indication; for above/below knee
– Preserves treatment options
• Atherectomy
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Limited studies – three
5/13 (38%) patent at 6 mts
largest study
expensive
Bioabsorbable Stents
• Constructed of polylactic acid
– Two layers : anti-proliferation drug that absorbs and second
is made of a harder crystalline matrix of PLA which
dissolves in two years
• Biodegradable magnesium alloy dissolves in months
• Also a vehicle for delivery of nanoparticles
Drug Eluding Balloons
• Targeted delivery of
drugs to vascular wall
or perivascular region
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Antigrowth factors
Angiogenesis factors
Gene therapy
Injection of cells
Local delivery
concentrations can be
500x greater than
systemic therapy
Drug Eluding Balloons
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InPact Admiral Balloon (paclitaxil)
40 patients (only AVF’s) randomized 1:1
No defined prospective F/U
TLR-free survival was significantly superior in
the PCB group 308 d vs 161 d.
• However, device success rates were 100% in
the HPB group and 35% in the PCB group
• JVIR 2015 – in press
Drug Eluding Balloons
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Adventitial delivery
130 micron needle
Controlled localized delivery
Reduced toxicity
Drug Eluding Balloons
• Questions to be answered
– Drug dose
– Pre PTA or Post PTA
– Duration of dwell time
Question Should be PTA versus Stent Garfts
• No definite evidence that proves stents are better
than angioplasty for patency for peripheral and
central lesions
• Stents do improve technical success with some
evidence of improved effect (Vogel, JVIR 2005)
• Early randomized studies demonstrate clear patency
advantage of stent grafts
Self-expanding ePTFE Covered Stents
Viabahn
Flair
Viatorr
Fluency
Slide courtesy Bart Dolmatch
N Engl J Med 2010;362(6):494-503
(Core Lab Analysis)
Survival Free from Treatment Area Primary Patency
Failure
Log-Rank p=0.003
Wilcoxon p=0.008
FLAIR study
Of course, this is achievable with PTA, isn’t it?
2 mos
29 mos
s berman
AVG functions 5 years after placement.
Revise Trial
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Presented at SIR
Gore Viabahn device for venous anastomotic stenosis
Six month primary patency significantly different
Secondary patency the same
Renova
– 12-month ACPP for the stent graft group was significantly
better than the PTA group, 24.1% vs. 10.3% (p=0.005),
respectively.
Literature (Cephalic Arch)
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Randomized Study
Stent versus stent graft
25 patients
Six month primary patency was 82% in the stent graft
group and 39% in the bare stent group.
• One-year primary patency was 32% in the stent graft
group and 0% in the bare stent group
• Historical PTA 42% and stent 39% (Rajan vs.
Shemesh)
• Shemesh, JVS 2008 48(6): 1524-1531
Another Study:
• 14 patients mature brachiocephalic fistulas.
• Five were randomized to angioplasty (PTA) and 9 to stent
grafting.
• Technical success 100%
• Mean patency in PTA group 100 days (56-154 days) vs 300
days (201-504 days) for SG
• Primary access circuit patency at 6 and 12 months:
– PTA: 0%
– Stent graft: 67 and 22% (95% CI: 42-100; 6-75) p<0.01
• Primacy target lesion patency at 3, 6 and 12 months
– PTA: 60% (CI 29-100%), 0% and 0%
– SG: 100%, 100% and 29% (CI: 9-93%) (p<0.01)
Surgical Intervention
• Anatomic bypasses
• Turn down cephalic vein to basilic or axillary
vein
• Autologous or artificial bypass
• Patch
• Skilled motivated surgeons needed
• Literature
• Not much short, medium or long term data
published
Literature
• Transposition of cephalic vein to axillary or basilic vein
• 13 Patients
• Six month primary patency rate of angioplasty before the
surgical revision of 8%
• Six month primary patency rate following surgical revision of
69% at 6 months.
• However:
– Why was PTA 8% so much lower than other studies
– Surgical revision is technically creating a new access
– No length of follow-up provided or standard error limiting
interpretation of data
– What about damage to axillary and basilic veins in the future?
• Kian, Sem Dialysis 2008: 21(1): 93-6.
AVF Stent Grafts
• 17 patients
• Thromboses, stenoses, pseudoaneurysms
• Access circuit patency: 88% at 6 and 12
months
• Lesion patency: 94% at 6 and 12 months
Bent CL, JVIR April 2010
Why Does Most Stuff Not Work?
• Intimal injury leading to intimal hyperplasia
– Have to inhibit or prevent injury, exclude injured
area
• Most devices repeat or create injury cycle
• Surgery itself associated with injury cycle
• Poor reporting/study design
– Mixing of grafts/fistulas/lesion types
– Type of follow-up
– definitions
Summary
• No evidence to date to suggest any new
devices / methods improve overall access
patency compared to angioplasty for venous
stenosis in hemodialysis patients
• Stents should be used for salvage only, not
primary intervention
• Stent grafts have improved patency in graft
patients – does this translate to fistulas?