GRAFT THROMBOSIS: RECENT TRENDS IN MANAGEMENT
Introduction
Most patients with end-stage renal disease undergo hemodialysis thrice weekly to Optimize their survival Minimize medical complications and Enhance their quality of life
A reliable vascular access is a Critical requirement for providing adequate
hemodialysis
Introduction
The ideal vascular access would be Easy to place Ready to use as soon as it is placed, Deliver high blood flows indefinitely, and Free of complications
None of the existing types of vascular access achieves this ideal
Among the three types of vascular access currently available, Native arteriovenous (AV) fistulas are superior to AV
grafts, which, in turn, are superior to dialysis catheters
Introduction
Recognizing the relative merits of the vascular access types, the Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines recommend placement of AV fistulas in at least 50% of hemodialysis
patients, AV grafts in 40%, and Dialysis catheters in no more than 10%
Loop Forearm Graft, Venous Preparation
SPECIFIC CRITERIA
PTFE A-V Graft
Autologous options have been considered / excluded / exhausted
(Exception : graft first may preserve future options)
Absence of Collagen Vascular Disease (Lupus Nephritis)
Generally, forearm before upper arm
(Exception : secondary upper arm graft on non-dominant side)
Superficial vein target preferable to deep vein
Min diam of venous target >4.5 mm, min length > 16 mm
Success upper arm graft limited if diam < 5 mm
Arterial target diam > 3.5 mm (4.0 mm upper arm)
Consider 5 mm graft
Consider crossing joint
Introduction
Vascular access procedures and their subsequent complications represent a major cause of Morbidity, Hospitalization, and Cost for chronic hemodialysis patients
AV grafts
AV grafts are prone to Recurrent stenosis and thrombosis and Require multiple radiologic or surgical
interventions to ensure their long-term patency for dialysis
AV graft thrombosis
About 80% of graft failures are due to thrombosis Thus, improving graft longevity requires
implementing measures to reduce the frequency of graft thrombosis When grafts are referred for thrombectomy, a
significant underlying stenosis is observed, most commonly at the venous anastomosis, the draining vein, or the central veins
This observation suggests that Prophylactic angioplasty of hemodynamically significant
graft stenosis may reduce the frequency of graft thrombosis, and thereby increase cumulative graft survival
AV graft thrombosis
Thrombosed grafts usually have an underlying stenosis, most commonly at the venous anastomosis
or in the draining vein Salvage of clotted grafts requires
Thrombectomy as well as Angioplasty or surgical revision of the
underlying stenosis
AV graft thrombosis
However, the primary patency (intervention free survival) is considerably worse after treatment of clotted grafts, as compared with Elective angioplasty of patent grafts with stenosis
After elective angioplasty, the primary graft patency is 70 to 85% at 3 mo and 47 to 63% at 6 mo
In contrast, after thrombectomy and angioplasty of clotted grafts, the primary patency is only 33 to 63% at 3mo and 11 to 39% at 6 mo
AV graft thrombosis
Comparison of outcomes of 656 radiologic graft interventions performed at a single dialysis center found a 3-mo primary patency of 71% after elective angioplasty, as
compared with 30% after treatment of clotted grafts
Am J Kidney Dis 2001;37: 945–953
AV graft thrombosis
Given the dismal outcomes of clotted grafts, it would be desirable to Identify prospectively grafts that are at risk for
thrombosis and intervene prophylactically to prevent the graft from clotting
Because graft thrombosis is usually superimposed on hemodynamically significant stenosis, it is a plausible hypothesis that timely detection and correction of the stenosis will prevent graft thrombosis
Clin J Am Soc Nephrol 2007;2: 786–800
AV graft thrombosis
Achieving this goal requires having a Simple Cheap Reproducible, and Sensitive method to
Monitor for graft stenosis
Clin J Am Soc Nephrol 2007;2: 786–800
Mechanical Interventions to Reduce Graft Thrombosis
Approaches for detection of graft stenosis Clinical monitoring consists of physical
examination (absent thrill, abnormal bruit, or distal edema),
Abnormalities identified during dialysis sessions Prolonged bleeding from needle sites or Difficulty in cannulation), or
An unexplained decrease in Kt/V on a constant dialysis prescription
Clin J Am Soc Nephrol 2007;2: 786–800
NKF KDOQI GUIDELINES 2006 Updates Vascular Access
AVGs have the following advantages: A large surface area and vessel available for
cannulation initially They are technically easy to cannulate The lag-time from insertion to maturation is
short For PTFE-derived grafts, it is recommended that not
less than 14 days should elapse before cannulation to allow healing and incorporation of the graft into local tissues, although ideally, 3 to 6 weeks are recommended
Multiple insertion sites are available
NKF KDOQI GUIDELINES 2006 Updates Vascular Access
AVGs have the following advantages: A variety of shapes and configurations is
available to facilitate placement It is easy for the surgeon to handle,
implant, and construct the vascular anastomosis
The graft is comparatively easy to repair either surgically or endovascularly
NKF KDOQI GUIDELINES 2006 Updates Vascular Access
The sum of the available data, until recently, supported PTFE grafts over other biological and other synthetic materials, based on lower risk for disintegration with infection,
longer patency, better availability, and improved surgical handling Biological grafts (bovine heterografts) have
greater reported rates of complications compared with synthetic grafts
NKF KDOQI GUIDELINES 2006 Updates Vascular Access
For nearly 2 decades, PTFE has been the material of choice for bridge
grafts. However, during the past decade, modifications
and the use of other materials, such as PU,
cryopreserved femoral vein, bovine mesenteric vein, and hybrids with self-sealing composite material, have been developed and used
None of these has shown any “survival” patency over plain PTFE, except for the composite/PU graft
NKF KDOQI GUIDELINES 2006 Updates Vascular Access
Composite/PU graft Has an advantage because of its self-
sealing property to be cannulated within hours, if needed, for dialysis
As a result, it can be placed without having to use a catheter for initiation of dialysis therapy, in some cases Direct comparisons between PTFE and human
umbilical cord vein grafts and other synthetic polymers have not been made
NKF KDOQI GUIDELINES 2006 Updates Vascular Access
Treatment of thrombosis and associated stenosis:Each institution should determine which procedure, percutaneous thrombectomy with angioplasty or surgical thrombectomy with AVG revision, is preferable based upon expediency and physician expertise at that center.
6.7.1 Treatment of AVG thrombosis should be performed urgently to minimize the need for a temporary HD catheter. (B)
6.7.2 Treatment of AVG thrombosis can be performed by using either percutaneous or surgical techniques. Local or regional anesthesia should be used for the majority of patients. (B)
6.7.3 The thrombectomy procedure can be performed in either an outpatient or inpatient environment. (B)
NKF KDOQI GUIDELINES 2006 Updates Vascular Access
6.7.4 Ideally, the AVG and native veins should be evaluated by using intraprocedural imaging. (B)
6.7.5 Stenoses should be corrected by using angioplasty or surgical revision. (B)
6.7.6 Methods for monitoring or surveillance of AVG abnormalities that are used to screen for venous stenosis should return to normal after intervention. (B)
NKF KDOQI GUIDELINES 2006 Updates Vascular Access
Outcomes after treatment of AVG thrombosis:After percutaneous or surgical thrombectomy, each institution should monitor the outcome of treatment on the basis of AVG patency. Reasonable goals are as follows:
6.8.1 A clinical success rate of 85%; clinical success is defined as the ability to use the AVG for at least 1 HD treatment. (B)
6.8.2 After percutaneous thrombectomy, primary patency should be 40% at 3 months. (B)
6.8.3 After surgical thrombectomy, primary patency should be 50% at 6 months and 40% at 1 year. (B)
Clin J Am Soc Nephrol 2007;2: 786–800
Clin J Am Soc Nephrol 2007;2: 786–800
Options for treating steal DRIL procedure distal
revascularization-interval ligation
excision of a portion of the vein
plication w/ mattress or continuous sutures
crossed PTFE band interposition of a 4 mm
PTFE
Treatment of venous access complications.
Venous angioplasty Graft thrombolysis
Contraindications to Thrombolytic Therapy
Absolute
Recent major bleeding Recent stroke Recent major surgery or trauma Irreversible ischemia of end organ Intracranial pathology Recent ophthalmologic procedure
Relative
History of gastrointestinal bleeding or active peptic ulcer disease Underlying coagulation abnormalities Uncontrolled hypertension Pregnancy Hemorrhagic retinopathy
Recent articles
Patency rate and complications of polytetrafluoroethylene grafts compared with polyurethane grafts for hemodialysis access. RESULTS:
One-year patency rate was reported to be 64% and 52% in the PTFE and PVAG groups, respectively. There was no significant difference in 1-year (64% versus 52%) and 2-year (49% versus 41%) patency rate of the PTFE and PVAG grafts used as vascular access. There was also no difference between the numbers of complications reported in the two groups.
CONCLUSION: It could be concluded that either PTFE or PVAG grafts can be used
with the same expected outcomes
Ups J Med Sci. 2010 Nov;115(4):245-8
Long-term Outcome of a Cuffed Expanded PTFE Graft for Hemodialysis Vascular Access Compared to the standard ePTFE, the
cuffed ePTFE graft provided better long-term outcome, especially in terms of secondary patency rates after radiological intervention
World Journal of Surgery Volume 32, Number 8, 1827-1831
Balloon Angioplasty Versus Surgical Revision for Thrombosed Dialysis Graft Outlet Stenosis After Graft Thrombectomy The result of dialysis graft outlet balloon
angioplasty was comparable to that of surgical revision. Considering the invasiveness, balloon angioplasty should be considered when treating thrombosed dialysis grafts.
ANGIOLOGY August 2010; 61 (6):580-583
12 F. Catheter
Multi-side-hole tip
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