AJR 2001; 177:317-318
© American Roentgen Ray Society
A Rapid Low-Cost Uncrossed Sheath Method for Clearing Thrombosed Hemodialysis Grafts
Edward B. Strauss1,
Bradley N. Delman2 and
Avelino Maitem1
1
Department of Diagnostic Radiology, Section of Interventional Radiology,
Norwalk Hospital, Maple St., Norwalk, CT 06856.
2
Department of Radiology, Box 1234, Mount Sinai Medical Center, One Gustave L.
Levy PI., New York, NY 10029.
Received January 5, 2001;
accepted after revision February 12, 2001.
Address correspondence to E. B. Strauss.
Introduction
Many percutaneous techniques for treating thrombosed hemodialysis grafts
have been described in the literature
[1,2,3,4].
All require crossed sheaths (puncture of the arterial side of the graft
directed toward the venous anastomosis and vice versa), which are potentially
disadvantageous but necessary, to permit clearance of the space between the
punctures. Crossed sheaths place the operator, particularly the operator's
hands, very close to the radiation field and are less convenient for
subsequent hemodialysis than uncrossed sheaths. Our method avoids the
necessity for crossed sheaths by using a balloon inflated occlusively within
the arterial side of the graft so that injection of heparinized saline
solution expels all thrombus from the graft, including the space between the
sheaths. We refer to this method as balloon luminal occlusion with forced
injection of saline solution and heparin (BLOWFISH).
Materials and Methods
We developed several variations of the BLOWFISH method and used this method
for 197 graft declottings between February 1997 and October 2000. All patients
but one had arm loop grafts arising from the brachial artery, the proximal
parts of the radial artery, or the ulnar and intraosseous trunk. One patient
had a leg loop graft, and no patients had straight grafts. We initially
performed procedures with and without thrombolytics, on the basis of the
operator's preference, with comparable technical success. However, we now
favor the routine use of thrombolytics, presently tissue plasminogen activator
(tPA) because procedure times are shorter. We have had two failures, both in
the same patient and the only one in our series with a leg graft; both
failures were caused by our inability to gain access to the graft because of a
seroma. No clinical events suggestive of pulmonary embolus have occurred, but
we have not evaluated for occult embolic disease. We describe the basic method
we use most often with tPA.
First, the arterial side of the graft is accessed with the puncture
directed toward the arterial anastomosis. A short 5.5-French vascular sheath
with a large-diameter side arm (Check-Flo Performer Introducer; Cook,
Bloomington, IN), suitable for later hemodialysis, is introduced. A straight
0.035-inch guidewire is advanced into the native brachial artery over which a
5-French Fogarty catheter (Walrus; Arrow, Woburn, MA) is passed. The balloon
is inflated in the brachial artery (Fig.
1A) and drawn back to the sheath, clearing the arterial
anastomosis and the proximal part of the graft. This procedure is conventional
but, with other methods, would be performed last.
Second, the Fogarty balloon is deflated fully, advanced to a position
within the graft roughly half-way between the arterial anastomosis and the
sheath, and inflated to completely occlude the graft. The balloon will visibly
flatten against the walls of the graft indicating adequate inflation. The
balloon is left inflated until the procedure is completed. Anything injected
through the arterial sheath is now forced into the thrombosed graft and beyond
into the native vein (Fig.
1B).
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Fig. 1B. —Drawings illustrate schematic of uncrossed sheath method for
clearing thrombosed hemodialysis grafts. Fogarty balloon inflates occlusively
within arterial side of graft; tissue plasminogen activator and heparin are
injected through arterial sheath and are forced into thrombosed graft.
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At this point, 5-10 mL of 2 mg of tPA and 3000 U of heparin is injected
slowly through the arterial sheath. Even a small amount of tPA injected in
this manner substantially liquefies the thrombus in minutes, and the time
required for the next few steps is more than adequate to ensure substantial
thrombolysis.
Third, the venous side of the graft is accessed with the puncture directed
toward the venous anastomosis, and a second sheath is introduced. Contrast
material injected through the sheath cannot reflux into the graft and, as a
result, will usually permit diagnostic venography even without introduction of
a catheter. If venous stenosis is present, angioplasty can be performed at
this time (Fig. 1C). After
dilatation, the angioplasty balloon is removed, but a guidewire remains in
place until technical success is achieved.
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Fig. 1C. —Drawings illustrate schematic of uncrossed sheath method for
clearing thrombosed hemodialysis grafts. Contrast material is injected through
venous sheath to treat venous stenosis with angioplasty.
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Fourth, 30 mL of heparinized saline solution (10 U/mL heparin) is injected
through the arterial sheath (Fig.
1D), displacing all the liquefied thrombus from the graft and
native veins. Excessive pressure is not required; it is the volume of fluid
injected into the sheath that seems to matter.
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Fig. 1D. —Drawings illustrate schematic of uncrossed sheath method for
clearing thrombosed hemodialysis grafts. Heparinized saline solution is
injected through arterial sheath to clear liquefied thrombus from graft and
native vein.
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When the Fogarty balloon is deflated, blood flow is usually restored.
Sometimes, thrombus reforms in the proximal part of the graft but is easily
cleared by one more pass with the Fogarty balloon from the native artery to
the graft. Residual thrombus within the graft is seldom seen, but if present,
it can be cleared by repeating the injection of heparinized saline solution
against the occlusively inflated balloon.
Fifth, a diagnostic study is performed by injecting contrast material into
the native brachial artery (usually by advancing the deflated Fogarty
catheter) to evaluate for arterial stenosis, residual thrombus, and failure of
venous angioplasty. Further intervention can be performed if needed. Finally,
the sheaths are flushed and left in place for hemodialysis.
The BLOWFISH method is low in cost because no mechanical thrombolytic
device is required, and in fact, no equipment beyond the basics is required
for the other techniques used. A single, inexpensive, prepackaged (by most
hospital pharmacies) unit dose of 2 mg of tPA is optional.
Procedures tend to be rapid, averaging less than 25 min, with no additional
time needed to achieve hemostasis.
Discussion
We believe, as others have assumed, that the long-term patency of
hemodialysis grafts is not predicted by the method of graft clearance, but
rather by the identification and effective treatment of stenoses
[1,
2,
4]. If so, avoiding the use of
expensive mechanical thrombolytic devices makes sense. Also, the native artery
is protected from reflux of the thrombus during graft clearance, a
complication that is relatively common with standard methods
[5]. Most importantly, the
uncrossed sheaths make the procedure easier and more convenient for the
interventionist, the hemodialysis nurses, and the patient.
One potential shortcoming exists with this method: if stenosis occurs
within the graft itself and between the two sheaths, angioplasty would not be
possible without a separate crossed puncture. However, stenoses within grafts
are distinctly uncommon (we encountered none), and when present, they do not
respond well to angioplasty. If a lesion were detected, another puncture could
be performed, or treatment could be attempted at a later time.
The significance of pulmonary emboli is controversial, and the lengths to
which one should go to avoid them, debatable
[6,
7]. If the BLOWFISH method were
used without pharmacologic thrombolysis, thrombus from within the graft would
certainly embolize to the lungs, as it would from simple mechanical clearance
with crossed sheaths and a balloon. However, if the balloon occlusion and the
saline solution injection is performed with the venous sheath open, either
before venous angioplasty or after venous angioplasty and with the angioplasty
balloon re-inflated within the vein, a surprising amount of thrombus is
expelled from the venous sheath. Most recently, we began to perform this
method even when tPA was used and found it effective in removing essentially
all of the liquefied thrombus from the graft. It should be noted that other
pharmacologic methods do not expose the arterial plug to the action of the
thrombolytic, although the necessity and value of this are questionable. When
our method is used, the arterial plug is pulled into the graft and exposed to
the action of tPA, but we do not know the extent to which the plug actually
dissolves.
We have tried several methods for clearing thrombosed hemodialysis grafts,
but we now use the BLOWFISH method exclusively because of its speed, low cost,
and convenience.
References
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Valji K, Bookstein JJ, Roberts AC, Oglevie SB, Pittman C, O'Neill
MP. Pulse-spray pharmacomechanical thrombolysis of thrombosed hemodialysis
access grafts: long-term experience and comparison of original and current
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1995;164:1495
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Middlebrook MR, Amygdalos MA, Soulen MC, et al. Thrombosed
hemodialysis grafts: percutaneous mechanical balloon declotting versus
thrombolysis. Radiology
1995;196:73
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Cynamon J, Lakritz PS, Wahi SI, Bakel CW, Sprayregen S.
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Trerotola SO, Vesley TM, Lund GB, Soulen MC, Ehrman KO, Cardella
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Radiology
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Trerotola SO, Johnson MS, Shah H, Namyslowski J. Backbleeding
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Dolmatch BL, Gray RJ, Horton KM. Will iatrogenic pulmonary
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Introduction
Materials and Methods
