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Figure 42. 9 An ascending phlebogram evaluates venous patency prior to catheter removal, a er the patient is therapeutic on warfarin. From:Comerota AJ,
Gale SS. Contemporary venous thrombectomy. In:Fischer JE, Bland KI, eds. Maste ry of surgery , 5e. Philadelphia , PA:Lippincott Williams & Wilkins. 2006. Used with permission.
both ends exit the skin. Both ends of the suture are passed
through the holes of a sterile button, which is secured snugly
to the skin when the catheter is removed. is obliterates
the proximal posterior tibial vein and eliminates the risk
of bleeding following catheter removal. Prior to catheter
removal, an ascending phlebogram is performed through
the catheter to once again examine the veins phlebographically (Figure42.9).
POSTOPERATIVE DETAILS
19. A er wound closure, antibiotic ointment and sterile dressings are placed on the wounds. e patient’s leg is
wrapped with sterile gauze and multilayered elastic bandages from the base of the toes to the groin. e bandages
are snugly applied, with the posterior tibial vein catheter
exiting between the layers of the bandage on the lowerleg.
20. Full anticoagulation is continued postoperatively
with UFH through the catheter in the posterior tibial vein.
e heparin solution and pump are attached to an IV pole
with wheels and the patient is allowed (encouraged) to
ambulate. Oral anticoagulation is begun when the patient is
awake and resumes oral intake. e heparin infusion is continued for a minimum of 4–5 d and the INR reaches2–3.
21. Intermittent pneumatic compression garments are
used on both legs during the postoperative period when the
patient is not ambulating.
22. Prior to removing the posterior tibial vein catheter, a
predischarge ascending phlebogram is obtained to evaluate
patency of the femoropopliteal and iliofemoral venous segments. In the presence of an AVF, there may be signi cant
washout of contrast in the common femoral vein, thereby
mitigating good visualization of the iliac venous segments.
Any signi cant stenosis in the iliofemoral venous segment
should be treated to maintain unobstructed venous drainage into the venacava.
23. Oral anticoagulation is continued for an extended
period of time, at least 1year in all patients and inde nitely
inmany.
24. Upon discharge the patient is prescribed 30–40
mmHg ankle gradient compression stockings and instructed
to wear the stockings from the time he/she awakens in the
morning until bedtime. Compression stockings further
20,21
reduce postthrombotic sequelae.
DISCUSSION
e 2008 American College of Chest Physicians (ACCP)
Evidence-based Clinical Practice Guidelines (8th ed.) recommends that patients with iliofemoral DVT should be
considered for a management strategy designed to remove
thrombus from the iliofemoral system in order to reduce
22
postthrombotic sequelae (Grade2B).
Many patients
are now treated as outpatients for acute DVT. However,
when common femoral vein thrombosis with occlusion is
identi ed by venous duplex, we would recommend that
the patient be hospitalized and the strategy that is summarized in Figure42.10 adopted. If the patient is not a
candidate for catheter-directed thrombolysis, the recommendation for venous thrombectomy (Grade 2C) should
b e f o l l o w e d .
348 • VENOUS THROMBOEMBOLISM
Management of Iliofemoral DVT
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Immediate Anticoagulation Rapid CT Scan with Contrast
Leg elevation
Long leg compression
Ambulation Permitted
• Head
• Chest
• Abdomen
• Pelvis
No
No
PM rombolysis
CD rombolysis
Anticoagulation
plus
Compression
Figure 42. 10 Algorithm:Recommended treatment for iliofemoral venous thrombosis. From:Comerota AJ, Gale SS. Contemporary venous thrombectomy. In:Fischer JE, Bland KI,
eds. Mastery of surgery , 5e. Philadelphia, PA:Lippincott Williams & Wilkins. 2006. Used with permission.
Successful thrombus removal results in improved qual-
ity of life and fewer postthrombotic sequelae.
Patient Physically Active
Strategy of rombus Removal
Contraindication to rombolysis
and/or
Correct Underlying Venous Lesion
13–15,23
Aran-
• Correct Iliac Vein Stenosis
• Arteriovenous Fistula
• Catheter-Directed Anticoagulation
thrombectomy if they present within 10 d of the onset of
theirDVT.
domized trial of catheter-directed thrombolysis versus
anticoagulation has shown better patency and preserved
valve function in those treated with thrombolytic ther-
24
Patients who have iliofemoral DVT and contrain-
apy.
dications to lytic therapy should be considered for venous
sion
contraindication to thrombolysis, are poor operative candidates, have a prolonged duration of venous thrombosis, or
are critically ill or bedridden.
Ye s
Evaluate Vena Cava
Ye s
Venous rombectomy
Filter for Free-
Floating rombus
Aggressive anticoagulation combined with leg compres-
20,21
is the preferred treatment for patients who have a
Contemporary venous thrombectomy has substantially
Table42.4 VENOUS THROMBECTOMY:COMPARISON
OF OLD AND CONTEMPORARY TECHNIQUES
improved the early and long-term results of patients with
extensive DVT compared to the initial reports. e major
technical di erences between the initial and contemporary
TECHNIQUE OLD CONTEMPORARY
Pretreatment phlebography/
CT scan
Venous thrombectomy
catheter
Operative uoroscopy/
phlebography
Correct iliac vein stenosis (stent) No Yes
Arteriovenous stula No Yes
Infrainguinal thrombectomy No Yes
Full post-op anticoagulation Occasionally Yes
Catheter-directed
anticoagulation
IPC post op No Yes
IPC, intermittent pneumatic compression
Adapted from Comerota AJ, Gale SS. Surgical venous thrombectomy for
iliofemoral deep vein thrombosis. In:Greenhalgh RM, ed. Towards vascular and
endovascular consensus . London:BIBA Publishing. 2005. Used with permission.
Occasionally Always
No Yes
No Yes
No Yes
procedures are listed in Table42.4. Recent reports of those
performing venous thrombectomy and the long-term results
of a large Scandinavian randomized trial con rm signi cant
bene t compared to anticoagulation alone. erefore, vascular surgeons should include contemporary venous thrombectomy as part of their routine operative armamentarium.
R E F E R E N C E S
1. Mahorner H , Castleberry JW , Coleman WO . Attempts to restore
function in major veins which are the site of massive thrombosis , Ann
Surg. 1957 . 146 ( 3 ): 510–522 .
2. Haller JA , Abrams BL . Use of thrombectomy in the treatment of
acute iliofemoral venous thrombosis in forty- ve patients , Ann Surg.
1963 . 158 : 561–569 .
3. Lansing AM , Davis WM . Five-year follow-up study of iliofemoral
venous thrombectomy , Ann Surg. 1968 . 168 ( 4 ): 620–628 .
4. Karp RB , Wylie EJ . Recurrent thrombosis a er iliofemoral venous
thrombectomy , Surg Forum. 1966 . 17 : 147 .
OPERATIVE VENOUS THROMBECTOMY • 349
5. Piquet P . Traitement chirurgical des thromboses iliocaves:Exigences
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et resultats. In: Kie er E , ed. Chirurgie de la veine cave inferieure et de
ses branches . Paris : Expansion Scienti que Francaise . 1985 . 210–216 .
6. Einarsson E , Albrechtsson U , Eklof B . rombectomy and temporary AV- stula in iliofemoral vein thrombosis:Technical considerations and early results , Int Angiol. 1986 . 5 ( 2 ): 65–72 .
7. Vollmar JF . Robert May memorial lecture:Advances in reconstructive venous surgery, Int Angiol. 1986 . 5 ( 3 ): 117–129 .
8. Juhan C , Alimi Y , Di Mauro P , Hartung O . Surgical venous thrombectomy , Cardiovasc Surg. 1999 . 7 ( 6 ): 586–590 .
9 . To r n g r e n S , S we d e n b o r g J . rombectomy and temporary
arterio-venous stula for ilio-femoral venous thrombosis , Int Angiol .
1988 . 7 ( 1 ): 14–18 .
10. Rasmussen A , Mogensen K , Nissen FH , Wadt J , Skibsted L . Acute
iliofemoral venous thrombosis:26 cases treated with thrombectomy,
temporary arteriovenous stula, and anticoagulants , Ugeskr Laeger .
1990 . 152 ( 40 ): 2928–2930 .
11. Neglen P , al- Hassan HK , Endrys J , Nazzal MM , Christenson JT ,
Eklof B . Iliofemoral venous thrombectomy followed by percutaneous closure of the temporary arteriovenous stula , Surgery. 1991 .
110 ( 3 ): 493–499 .
12. Eklof B , Kistner RL . Is there a role for thrombectomy in iliofemoral
venous thrombosis?, Semin Vasc Surg. 1996 . 9 ( 1 ): 34–45 .
13. Plate G , Einarsson E , Ohlin P , Jensen R , Qvarfordt P , Eklof B .
rombectomy with temporary arteriovenous stula: e treatment
of choice in acute iliofemoral venous thrombosis , J Vasc Surg. 1984 .
1 ( 6 ): 867–876 .
14. Plate G , Akesson H , Einarsson E , Ohlin P , Eklof B . Long-term results
of venous thrombectomy combined with a temporary arterio-venous
stula , Eur J Vasc Surg. 1990 . 4 ( 5 ): 483–489 .
15. Plate G , Eklof B , Norgren L , Ohlin P , Dahlstrom JA . Venous
thrombectomy for iliofemoral vein thrombosis:10-year results of
a prospective randomised study , Eur J Vasc Endovasc Surg. 1997 .
14 ( 5 ): 367–374 .
16. Comerota AJ , Aldridge SC , Cohen G , Ball DS , Pliskin M , White
JV . A strategy of aggressive regional therapy for acute iliofemoral
venous thrombosis with contemporary venous thrombectomy or
catheter-directed thrombolysis , J Vasc Surg. 1994 . 20 ( 2 ): 244–254 .
17. Comerota AJ , Gale SS . Technique of contemporary iliofemoral
and infrainguinal venous thrombectomy, J Vasc Surg. 2006 . 43 ( 1 ):
185–191 .
18. Eklof B , Juhan C . Revival of thrombectomy in the management of
acute iliofemoral venous thrombosis ,
Contemp Surg. 1992 .
40 : 21 .
19. Akesson H , Brudin L , Dahlstrom JA , Eklof B , Ohlin P , Plate G .
Venous function assessed during a 5 year period a er acute
ilio-femoral venous thrombosis treated with anticoagulation , Eur J
Vasc Surg. 1990 . 4 ( 1 ): 43–48 .
20. Brandjes DP , Buller HR , Heijboer H , et al. Randomised trial of
e ect of compression stockings in patients with symptomatic
proximal-vein thrombosis , Lancet. 1997 . 349 ( 9054 ): 759–762 .
21. Prandoni P , Lensing AW , Prins MH , et al. Below-knee elastic
compression stockings to prevent the post-thrombotic syndrome:
A randomized, controlled trial , Ann Intern Med. 2004 . 141 ( 4 ):
249–256 .
22. Kearon C , Kahn SR , Agnelli G , Goldhaber SZ , Raskob G ,
Comerota AJ . Antithrombotic therapy for venous thromboembolic
disease:ACCP evidence-based clinical practice guidelines (8th ed),
Chest. 2008 . 133 ( 6 ): 454S–545S .
23. Comerota AJ , r o m R C , M a t h i a s S D , H a u g h t o n S , M e w is se n
M . Catheter - directed thrombolysis for iliofemoral deep venous
thrombosis improves health-related quality of life , J Vasc Surg. 2000 .
32 ( 1 ): 130–137 .
24. Elsharawy M , Elzayat E . Early results of thrombolysis vs anticoagulation in iliofemoral venous thrombosis:Arandomised clinical trial ,
Eur J Vasc Endovasc Surg. 2002 . 24 ( 3 ): 209–214 .
25. Meissner AJ , Huszcza S . Surgical strategy for management of deep
venous thrombosis of the lower extremities , World J Surg. 1996 .
20 ( 9 ): 1149–1155 .
26. Pillny M , Sandmann W , Luther B , etal. Deep venous thrombosis
during pregnancy and a er delivery:Indications for and results of
thrombectomy , J Vasc Surg. 2003 . 37 ( 3 ): 528–532 .
27. Hartung O , Alimi YS , Di Mauro P , Portier F , Juhan C . Endovascular
treatment of iliocaval occlusion caused by retroperitoneal brosis:Late results in two cases , J Vasc Surg. 2002 . 36 ( 4 ): 849–852 .
28. Holper P , Kotelis D , Attigah N , Hyhlik-Durr A , Bockler D .
Longterm results a er surgical thrombectomy and simultaneous
stenting for symptomatic iliofemoral venous thrombosis, Eur J Vasc
Endovasc Surg. 2010 . 39 ( 3 ): 349–355 .
29. Ganger KH , Nachbur BH , Ris HB , Zurbrugg H . Surgical thrombectomy versus conservative treatment for deep venous thrombosis:
Functional comparison of long-term results , Eur J Vasc Surg. 1989 .
3 ( 6 ): 529–538 .
30. Kniemeyer HW , Sandmann W , Schwindt C , Grabitz K , Torsello G ,
Stuhmeier K . rombectomy with arteriovenous stula for embolizing deep venous thrombosis:An alternative therapy for prevention of
recurrent pulmonary embolism , Clin Investig. 1993 . 72 ( 1 ): 40–45 .
350 • VENOUS THROMBOEMBOLISM
43.
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PERMANENT VENA CAVA FILTERS
INDICATIONS, FILTER TYPES, AND RESULTS
Ali F. AbuRahma and Patrick A. Stone
INTRODUCTION
e incidence of pulmonary embolism (PE) is estimated
to be around 355,000 patients per year and results in as
1
many as 240,000 deaths per year in the United States.
e
standard treatment for PE remains therapeutic anticoagulation. However, 5 to 8% of patients receiving therapeutic
anticoagulation for PE experience a second PE episode.
2,3
Complications of anticoagulation also occur in up to 26%
2,3
of patients.
ere are many instances in which anticoagulation is either contraindicated or patients experience
a complication of anticoagulation necessitating its discontinuation. In these situations, inferior vena cava (IVC) lter
insertion is indicated to preventPE.
Since the introduction of the rst percutaneous
4
Green eld lter in 1984,
several lower pro le percutaneously inserted caval lters have been developed; and presently, ten devices are approved by the US Food and Drug
Administration.
THE IDEAL CAVALFILTER
Several ideal caval lter characteristics have been recog-
5
ese characteristics include: (1)biocompatible,
nized.
nonthrombogenic, with in nite implant lifetime performance; (2)secure xation within the IVC; (3)high ltering e ciency with no impedance of ow; (4)small caliber
delivery system with ease of percutaneous insertion with
a simple and controlled release mechanism amenable to
repositioning; (5)low access site thrombosis; (6)low cost;
(7)retrievability; (8)magnetic resonance imaging (MRI)
compatibility. Many of these features have been achieved
in some of the newer IVC devices; however, the ideal
device has yet to be developed. Long-term performance
characteristic of caval lters is particularly signi cant
in patients being considered for prophylactic IVC lter
insertion.
INDICATIONS AND
CONTRAINDICATIONS FOR
CAVAL FILTER INSERTION
Although the data on the bene t versus the risk of caval lters are limited, the use of these lters has increased dramat-
6
ically. Stein etal.
United States between 1979 and 1999 increased 2,000%.
reported that the use of caval lters in the
e number of patients who had caval lters increased from
2,000 in 1979 to 49,000 in 1999. Forty- ve percent of caval
lter insertions were in patients with deep vein thrombosis
(DVT) alone in 1999, 36% were in patients with PE, and
19% were in patients who were presumably at high risk, but
6,7
did not have DVT or PE listed as a discharge code.
Table 43.1 summarizes the various absolute and relative indications for IVC lter insertion. is table includes
the established indications for caval lter placement and
also summarizes indications that may be debatable or
8,9
controversial.
Overall, patients with complications of anticoagulation or contraindications to anticoagulation should be
managed with caval lter insertion alone. In certain cases,
both caval ltration and anticoagulation may be used to
protect patients, for example, patients with chronic PE
who are being considered for pulmonary embolectomy
or patients with severe cardiopulmonary compromise
that places them at greater risk if any additional embolic
insultsoccur.
Relative indications for caval lters included the presence of iliofemoral thrombosis with a free- oating tail
≥5cm long. Although this indication has been questioned
10
by a prospective trial,
thrombus with a free- oating tail
≥5 cm long may still be appropriately treated with caval
lters. Other such indications are septic PE, chronic PE in
patients with cor pulmonale, and high-risk patients including those with signi cant cardiopulmonary disease, occlusion of more than 50% of the pulmonary bed, or both, who
could not tolerate any recurrent thromboembolism.
351
Table43.1 INDICATIONS FOR IVC FILTER INSERTION
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A. Absolute Indications
1. Recurrent thromboembolic disease despite anticoagulation
therapy
2. Signi cant complication of anticoagulation therapy that
forced therapy to be discontinued
3. Uncontrolled anticoagulation:sub- or supratherapeutic
despite patient compliance
4 . Recurrent PE in a patient with an IVC lter in place
5. Contraindication to anticoagulation:
Bleeding complication of anticoagulation
Recent bleeding
Recent major trauma or surgery
Hemorrhagic stroke
Heparin-induced thrombocytopenia or thrombocytopenia
(<50,000/mm
Central nervous system neoplasm, aneurysms, or vascular
malformation
Guaiac-positive stools
6. In conjunction with pulmonary embolectomy
B. Relative Indications
1. Large, free- oating iliofemoral thrombus
2. Propagating iliofemoral thrombus despite adequate
anticoagulation
3 . romboembolic disease with limited cardiopulmonary
reserve
4. Chronic thromboembolic disease (undergoing pulmonary
embolectomy)
5. Poor compliance with medications
6. Septic PE
7 . Severe ataxia; at risk for falls on anticoagulation therapy
8. DVT thrombolysis
9 . Renal-cell cancer with renal vein or IVC involvement
10. Prophylactic in high risk patients:massive trauma, pelvic or
lower extremity fractures, head injury
3
)
Several authorities have suggested that the indications for lter insertions be made more liberal to include
patients who have sustained massive trauma and remain at
high risk of thromboembolism, but do not actually have
11–13
the disease.
Others have advocated the use of lters in
patients with malignancy who are at risk for PE or who have
14–17
thromboembolism.
e routine use of caval ltration
for DVT instead of anticoagulation in high-risk older surgical patients and in pregnant patients with DVT or PE have
18
also been advocated.
ere has been a change in vena cava lter placement
in some centers over the past decade. Yunus etal. reviewed
their institution’s experience and found a six-fold increase
in the number of IVC lters placed when comparing 1995
19
with 2005.
With a decreasing pro le of lters, a trend
toward more liberal indications for placement by their
center by increased number of lters placed for infrapopliteal DVT or for a prophylactic indication.
A signi cant change was also demonstrated by the specialty of the physician inserting the IVC lter. While interventional radiologists continued to place 50% of the lters,
the number of lters deployed by vascular/trauma surgeons
19
increased to 24%, and cardiologists decreased to29%.
e only known absolute contraindications to IVC
lter insertion are complete thrombosis of the IVC and
inability to gain access to the IVC. Replacement of IVC
lters in younger patients (adolescent age) should also be
avoided because of the lack of performance data lasting several decades. ese patients would likely have such devices
implanted for extended periods oftime.
PROPHYLACTIC CAVAL FILTER
INSERTION IN TRAUMA PATIENTS
Patients with multiple trauma have been considered for prophylactic caval lters. e usual prophylactic measures that are
useful in the prevention of thromboembolic disease in surgical or medical patients, o en fail in multiple trauma patients.
Prophylaxis is o en started too late in these trauma patients
and there is frequent venous stasis and/or associated venous
injury along with hypercoagulable states. Venous compression devices and venous surveillance ultrasonography cannot
be applied in many of these patients because of external xation devices, the extent of edema, or the application ofcasts.
Although several reports have advocated the use of caval
lters in high-risk trauma patients, others have cautioned
against routine prophylactic caval lter placement. In one
large series, prophylactic caval lters would not have bene ted 95% of high-risk patients without a DVT and would
20
not have prevented any deaths.
Most investigators have
attempted to identify trauma patients at particularly high
risk for thromboembolism and recommended prophylactic
21,22
caval lter insertion.
ese high-risk patients (e.g., brain
or spinal cord injury, pelvic, and multiple long bone fractures) have been demonstrated to have a y-fold increase
in thromboembolic complications compared with other
trauma patients. Most studies have demonstrated favorable
outcomes with caval lters in such patients, however others
12,21–24
have failed to show this bene t.
25
Wojcik etal.
reported on a series of 105 blunt trauma
patients who were treated with permanent caval lters for
treatment of DVT and prophylaxis, with a mean follow-up
of 29months. ere was no PE in the patients in whom lters
were placed, and no patients experienced any clinically significant complications related to caval lter insertions. ey also
reported minimal migration of only one lter and one caval
occlusion (0.95%). However, eleven patients (10.4%) experienced symptoms of leg swelling a er hospital discharge, and
twenty-eight of the sixty-four patients with prophylactically
placed caval lters had a DVT a er lter placement.
352 • VENOUS THROMBOEMBOLISM
Rodriguez et al. 13 also reported on their experience of
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Green eld lter insertions in trauma patients within 48 h,
with a PE-related mortality decrease from 17 to 2.5%, and
only two of forty patients developed signi cant venous stasis of the lower extremities.
26
Leon et al.
reported on the prophylactic use of IVC
lters in seventy-four patients undergoing high-risk spinal
surgery. Criteria for usage were (1) history of thromboembolism, (2) diagnosed thrombophilia, (3) malignancy,
(4)bed-ridden for over 2 weeks prior to surgery, (5)staged
procedures or multiple levels, (6)combined anterior/posterior approaches, (7)expected need for signi cant iliocaval
manipulation during exposure, and (8) single-stage anesthetic time over an 8-h period. Seventy patients had at least
two risk factors. Patients were evaluated for lter complications, DVT, and PE. At a mean follow-up of 11months, one
patient developed PE. Twenty-seven limbs in twenty-three
patients developed DVT. Five limbs had isolated calf DVT,
and twenty-two had proximal vein involvement. Insertion
site DVT accounted for nearly one-third of the DVTs.
Six patients died from unrelated complications. ey concluded that despite the high incidence of DVT following
high-risk spinal surgery, prophylactic caval lter placement
26
appears to protect patients fromPE.
With the advances in the use of retrievable lters, the
indication of prophylactic caval lters in trauma patients
may be justi ed.
PROPHYLACTIC CAVAL INSERTION IN
PATIENTS WITH MALIGNANCY
Patients with malignancies have hypercoagulable states and
14,27
experience frequent thromboembolic events.
Some studies suggest that despite adequate anticoagulation, thromboembolism can occur in such patients to a greater degree than
in other patients. e associated comorbidities of patients
with malignancies undergoing cancer therapy frequently
places them at greater risk for bleeding complications from
anticoagulation. e use of caval lters in these patients has
been applied with con icting results. In a recent report,
the American College of Chest Physicians Consensus
Committee on PE discouraged the routine use of IVC lters in cancer-associated DVT/PE and recommended the
use of anticoagulation therapy until a randomized controlled study comparing the two modalities becomes avail-
20
e use of lters has also been criticized in these
able.
patients because of the high cost and high mortality rate
14
experienced in these patients in many IVC lter studies.
embolism.
28
erefore, in septic patients who have a contraindication to anticoagulation, the physician must choose
between placing the caval lter in contradiction to FDA
guidelines and leaving the patient at increased risk of PE.
However, this has been challenged recently. Areview of a
registry of 2,600 patients in whom Green eld lters were
inserted over a 15-year period suggests that lter placement
may be a safe method of PE prophylaxis in septic patients.
29
In reviewing 175 patients in this study with a diagnosis of
sepsis at the time of caval lter placement, they noted an initial 33% mortality rate in this group, however the mortality
leveled out over time, suggesting the cause of death is related
not to caval lter insertion but rather to the process of sepsis itself. No lters were removed from any patients, and the
recurrent PE rate was 1.7%. us, it appears that caval lter
placement in septic patients receiving appropriate antibiotics, especially patients with contraindications to anticoagulation, may bene t from caval interruption. It should be noted
that the employed lters in this study are made of titanium
and stainless steel, both of which are inert materials.
C A V A L F I L T E R I N S E R T I O N
DURING PREGNANCY
e choice of therapy for DVT of the lower extremity during pregnancy has been widely debated. Warfarin passes
through the placenta to the fetus and may cause fetal complications and/or death. Heparin, in contrast, does not cross
the placenta, but its long-term use may be impractical and
may increase the risk of bleeding, osteoporosis, and neurological complications.
18
AbuRahma etal.
analyzed eighteen pregnant patients
who had Green eld lters inserted for DVT of the lower
extremity and/or PE. e DVT diagnosis was made using
duplex imaging. Conventional full-dose intravenous heparin was initiated until the lter was inserted, followed by
subcutaneous heparin until labor, and continued for 6 weeks
postpartum in thirteen patients who were breast-feeding.
Warfarin was given postpartum in the other ve pati ents. e
indications for Green eld insertion included three patients
with PE while on anticoagulation, two with signi cant
bleeding secondary to anticoagulation, four for free- oating
iliofemoral DVT, two for heparin-induced thrombocytopenia, and seven with iliofemoropopliteal DVT occurring 1–3
weeks prior to labor, for prophylactic reasons. e mean
uoroscopy time during lter insertion was less than two
minutes. ere was no fetal or maternal morbidity or mortality. In long-term follow-up (mean:78months), no PE or
lter-related complications were encountered.
CAVAL FILTER INSERTION IN
SEPTIC PATIENTS
e FDA guidelines for intravascular lters state that lters
should not be implanted in patients with a risk of septic
THE RESULTS OF IVC FILTERTRIALS
e available data suggest that the risk of caval lter placement for prevention of recurrent PE is justi ed in the face of
PERMANENT VENA CAVA FILTERS • 353
contraindications and failure of anticoagulation. Since caval
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lters are considered the standard of care in such instances,
30
controlled trials for these indications may be unethical.
Well-designed randomized prospective trials to deter-
mine the clinical role for caval lters are mostly lacking,
30
although numerous case studies documenting the outcomes of widely used caval lters have been published. e
large randomized study (Prevention du Risque d’Embolie
Pulmonaire par Interruption Cave Study Group [PREPIC])
assessing the value of caval lters compared with standard
31
anticoagulation therapy was published in 1998.
is study
included 400 patients with proximal lower extremity DVT
who were at risk for PE; 200 patients were randomized to
a lter group (four di erent lters were used:the titanium
Green eld, Bird’s Nest, Vena Tech, and Cardil), and 200
were randomized to a non lter group. Both groups received
standard anticoagulation. e rate of recurrent venous
thromboembolism (recurrent PE and/or DVT), death, and
major bleeding were analyzed at 12days and 2years. is
study concluded that the bene cial e ect of an IVC lter in
PE prevention (1.1% versus 4.8% at day 12, p=0.03) was
outweighed by an excess of recurrent DVT (20.8% versus
11.6% at 2years, p=0.02), without a decrease in overall
mortality.
is conclusion stimulated intense criticism for multiple reasons. First, the study was originally planned to
include 800 patients (44 sites), but because of di culty in
enrollment, this study was stopped a er only 400 patients
had enrolled. Second, the statistical power for comparing
PE incidences at 2years was extremely low because of a limited number of data points, which did not allow meaningful
assessment of delayed PE rates. ird, although the overall
mortality rates were similar, there were no deaths caused by
PE in the lter group, whereas 80% of the deaths in the non lter group were related to PE. Fourth, the study did not
include a group of patients who received IVC lters without concomitant anticoagulation, which accounts for the
majority of patients in clinical practice. Fi h, a higher rate of
recurrent DVT did not outweigh the bene t of a decreased
PE rate and reduced PE-related deaths because of greater
gravity of recurrent PE in comparison with recurrentDVT.
32
In 2000, White et al.
reported the results of a
population-based study of the e ectiveness of caval lters
among patients with venous thromboembolism and concluded that insertion of lters was not associated with a
signi cant reduction in the incidence of rehospitalization
32
for PE.
is study evaluated hospital discharge data from
California hospitals from 1991 to 1995 and was designed
to determine the cumulative incidence at 1year of rehospitalization for PE or venous thrombosis among patients
with thromboembolism treated with caval lters, compared
with the incidence in a control population with thromboembolism not treated with lters. ere were 3,622 patients
treated with lters, and 64,333 control patients were admitted with a diagnosis of venous thromboembolism. Patients
initially admitted with PE were signi cantly more likely to
be readmitted for PE than patients with an initial episode
of venous thrombosis only, among patients with caval lters
(relative risk of 6.72) and control patients (relative risk of
5.3). Risk-adjusted proportional hazards models showed no
signi cant di erence between patients treated with lters
and control patients in the relative hazard for readmission
for PE. is study was limited because the patients treated
with lters had signi cantly more comorbidities, a higher
frequency of previous PE, and a lack of information regarding anticoagulation therapy. e authors concluded that
patients with caval lters were at increased risk of caval
occlusion because of accumulation of thrombus at the level
of the lter, which was felt to be caused by clot accumulation during the time of recurrent thromboembolism.
33
In 2000, Athanasoulis et al.
reported a retrospective study with several di erent caval lters over a 26-year
period. A total of 1,765 lters were implanted in 1,731
patients. Areview of hospital records revealed a prevalence
of PE a er lter placement of 5.6%, with fatal PE occurring in 3.7% of patients. Major complications occurred in
0.3% of procedures and IVC thrombosis occurred a er
lter placement in 2.7%. ey concluded that caval lters
provided protection from life-threatening PE with minimal
morbidity and few complications.
TECHNICAL CONSIDERATIONS
FOR IVC FILTER INSERTION
Caval lter insertion is usually performed under uoroscopy, either in the operating room with C-arm uoroscopy
or in the radiology or endovascular suite, where better imaging can be obtained. Apreoperative venacavogram should
be obtained prior to lter insertion. e insertion of all
currently available IVC lters requires venous access using
the Seldinger technique. e introducer sheath is placed
over a dilator, which is advanced over 0.035- to 0.038-inch
guide wire. e lter is inserted into the sheath a er the
dilator and guide wire have been removed, placed in the
proper position, usually below the level of the renal vein
using an imaging technique, and deployed by unsheathing
technique. In the majority of cases, the ideal level of placement is L2 or L3; however placement in the suprarenal IVC
or superior vena cava may be indicated in some situations.
e entrance site is usually the femoral vein (preferably, the
right femoral) or the internal jugularvein.
e radiographic diameter of the IVC should be measured, with correction for magni cation, which can be as
much as 25%. Avery large cava (above 30mm in diameter)
may be found in patients with right-sided heart failure. It
may be safer to introduce separate lters into each iliac vein
in these patients. rombus within the cava should not be
allowed to contact the lter to prevent the propagation of
thrombus through the lter. If thrombus does extend to the
354 • VENOUS THROMBOEMBOLISM
level of the renal vein, or the distal IVC is thrombosed, the
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lter should be placed at the level of T12 (suprarenal). A er
removal of the carrier system and the guide wire, a follow-up
abdominal radiograph is obtained to con rm the position
of the lter.
IVC FILTER PLACEMENT AT
THE BEDSIDE USING DUPLEX
ULTRASONOGRAPHIC
TECHNIQUE
is technique has been very helpful in patients in the
34–36
intensive care unit.
Bedside placement of IVC lters
has several advantages, including minimizing the risk
of contamination of central lines and dislodgement of
intravenous catheters during transfer from the ICU to
the operating room or angiography suite. Many of these
critically ill patients are on mechanical ventilation with
continuous monitoring and/or on vasopressor support,
which makes their move to other areas of the hospital
rather di cult and hazardous. Many of these patients
also have unstable pelvic fractures or spinal injuries. ese
patients can have their IVC lters inserted using a movable uoroscopyunit.
Recently, the use of transcutaneous duplex ultrasonog-
raphy to visualize the IVC for placement of lters has been
34–36
adapted in several centers.
is technique has several
advantages, including the ability of performing the procedure at the bedside, avoiding the use of contrast material
with its potential nephrotoxicity and ionizing radiation.
e femoral veins, iliac veins, and the IVC can usually be
visualized using duplex technology. Similarly, the internal
jugular vein can be used as an access for the lter.
e patient is generally placed in the supine position
for abdominal ultrasound examination. It is advisable for
these patients to be NPO (for “nil per os,” or “nothing by
mouth”) or to have their tube feedings discontinued for several hours to facilitate visualization of the IVC. e vascular
technologist is generally positioned opposite to the operating surgeon. Once the IVC is identi ed and the renal veins
are located, a long J guide wire is inserted into the venous
access and can be visualized crossing the IVC. e delivery
system, including the lter, is passed over the guide wire and
can be visualized using the duplex ultrasound. Once the
delivery system is properly positioned, the IVC lter can
be deployed under direct vision. A er inserting the IVC lter, the delivery system is then removed. Aplain abdominal
X-ray is then obtained to con rm the proper lter position
(Figures43.1, 43.2, and43.3).
36
Conners etal.
reported on 284 patients (out of 325
patients) who underwent duplex ultrasound-guided IVC lter placement. Poor IVC visualization, IVC thrombosis, and
unsuitable anatomy prevented duplex ultrasound-guided
lter placement in forty-one patients (12%). ere were no
Figure 43. 1 Undeployed lter within delivery catheter. (From Reference36)
procedure-related deaths or septic complications. Technical
complications occurred in twelve patients (4%). Filter
misplacement occurred in six patients (2%), access thrombosis in one (<1%), migration in one (<1%), bleeding in
one (<1%), and IVC occlusion in three (1%). Pulmonary
emboli a er IVC lter placement occurred in one patient
with a misplaced lter. Average hospital charges related to
duplex ultrasound-guided lter placement were $2,388 less
than the uoroscopic placement charges.
Others have reported on the use of intravascular ultra-
35,37–39
sound for bedside insertion of IVC lters.
OTHER IMAGING MODALITIES
FOR IVC FILTER INSERTION
IVC lters have been traditionally inserted using conventional uoroscopy, and more recently, transabdominal
duplex ultrasound or intravascular ultrasound. Recently,
other authorities have evaluated the role of other modalities in evaluating the IVC for lter placement. Holtzman
40
reported on the successful use of CO 2 cavagrams in
etal.
Figure 43. 2 Green eld lter tip (arrow) at right renal vein-IVC
junction.
(From Reference36)
PERMANENT VENA CAVA FILTERS • 355
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Figure 43. 3 Filter deployed inIVC. (From Reference36)
twenty- ve adult trauma patients requiring IVC lter place-
41
ment, and Brown etal.
comparing gadolinium, CO
conducted a prospective study
, and iodinated contrast mate-
2
rial for planning IVC lter placement in forty patients. ey
concluded that CO
and gadolinium had limitations when
2
compared with iodinated contrast material. Gadolinium
provided superior consistency in identifying relevant landmarks for lter placement. CO
demonstrated signi cantly
2
greater mean correlative error than gadolinium at initial and
41
repeat readings.
USE OF SUBCLAVIAN VEIN FOR
INFERIOR VENA CAVA FILTER
INSERTION
With the increasing use of central venous catheters and dif culty in venous access in some patient populations, alternatives to the traditional jugular and femoral vein approaches
have been investigated.
Certain patient populations can pose challenges to
using the standard routes of IVC deployment. Trauma injuries can create di culties in jugular access secondary to cervical immobilization, as well as limited exposure to access
to femoral vessels secondary to lower extremity immobilization or fractures. Femoral vessel access may likewise be
compromised in patients with iliofemoral DVT. In addition, some patients requiring IVC lters may also require
long-term central venous catheter placement. Combined
placement of both a vena cava lter and a subclavian
long-term central catheter in these patients can provide a
single expeditious procedure, especially if other access sites
are compromised.
42
Davison et al.
reported successful placement of the
TrapEase lter in ve patients by using the antecubital
43
vein. Ricco etal.
reported successful placement of LGM
vena cava lters using the subclavian vein approach in eight
patients.
In 2004, we reported the results of 135 patients with
44
TrapEase IVC lter placement over a 2-year period.
In a
majority of cases, the choice of subclavian vein approach
was based primarily on surgeon preference. Other circumstances for subclavian vein deployment included cervical
immobilization secondary to trauma, desire for concomitant placement of a subclavian long-term central venous
access catheter, and patient body habitus limiting exposure
to the internal jugular vein. ere were 135 lters placed
during this 2-year period. e internal jugular vein approach
was used in y-six patients, the femoral vein approach in
thirty-nine patients, and the subclavian vein approach in
forty patients. irty-nine of the forty TrapEase lter placements using the subclavian vein were successful; twenty-six
were deployed through the right subclavian vein, and fourteen through the le subclavian vein. e single failed
subclavian deployment was due to the inability to pass the
guide wire adequately into the IVC a er successful cannulation of the right subclavian vein. No insertion complications were encountered. We concluded that the subclavian
vein provides an alternative site for access for the TrapEase
IVC lter.
SUPRARENAL IVC FILTER
PLACEMENT
In certain clinical circumstances, suprarenal caval lter
insertion is needed because it is impossible or inadvisable to place an IVC lter in the usual infrarenal location.
Indications of these lters include:(1)patients with renal
vein thrombosis, (2) infrarenal vena caval thrombosis,
(3)requirement for IVC ltration in the presence of ovarian vein thrombosis in the postpartum state or the presence
of a large patent le ovarian vein (pregnancy or childbearing age), (4)the presence of thrombus propagating proximal to a lter below the renal veins, (5) extensive IVC
thrombosis extending to or above the renal veins, including
tumor thrombus from hepatic or renal tumors, (6)malposition or migration of a prior lter above the renal veins, and
(7)recurrent PE following infrarenal IVC lter placement,
preferably a er an upper extremity emboli source has been
ruledout.
Several studies have concluded that suprarenal IVC l-
ter insertion is both safe and e ective with clear indications
45–47
for lter placement.
Ahigher rate of caudal migration
was noted compared to infrarenal caval lters. e optimum choice for suprarenal IVC lters is, perhaps, either
a titanium Green eld lter or a wire-guided stainless steel
Green eld lter.
48
Kalva et al.
reported a 20-year experience of patients
who had implants of suprarenal IVC lters. In their series of
seventy patients only one patient had a documented PE during follow-up. Additionally, thirty patients had follow-up
computed tomography (CT) of the abdomen at just over
1-year mean, and demonstrated thrombus in the lter in
three patients, penetration of the IVC in two and fracture
in one additional patient.
356 • VENOUS THROMBOEMBOLISM
S U P E R I O R V E N A C A V A F I L T E R
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INSERTION
Several authorities have reported their experience in small
case series, with placement of lters in the superior vena cava
49–53
(SVC).
ese authorities felt that superior vena cava lters were bene cial in certain clinical indications, however
others reported SVC thrombosis secondary to SVC lters.
53
Several studies have suggested that PE is not a rare complication of upper extremity DVT, however it is believed that
catheter-related upper extremity DVT can expose patients
to a greater risk of PE. Indications for these lters would
include contraindications to thrombolytic and anticoagulation therapy. e stainless steel Green eld lter is generally
believed to be an ideal choice for SVC ltration because of
its short length, alternating hook design, and being over the
wire, allowing tracking and precise positioning. Guide wire
entrapment may be more prone to occur with SVC lter
placement.
FILTER PLACEMENT IN
OVERSIZEDIVC
Oversized IVCs are generally de ned as IVCs more than
28 mm in diameter. e Bird’s Nest lter is the device
approved by the FDA for use in an oversized IVC. If this
device is not available, insertion of bilateral common
iliac vein lters is acceptable. It has also been noted that
the titanium Green eld lter and the new stainless steel
Green eld lter with alternating hooks may not be subject
to the same 28-mm-diameter IVC size limitation as the
original Green eld lter, with signi cantly better xation
in 34-mm-diameter IVCs. is is due to a wider base and
redesigned hook pattern.
AVAILABLE CAVAL FILTER DEVICES
STAINLESS STEEL GREENFIELD FILTERS
is lter is the “gold standard” to which all current and
future lters should be compared. It is stainless steel,
cone-shaped, and 4.6 cm in length from the apex to the
base. It consists of six legs that a x to the wall of the vena
54
cava with small recurved hooks.
e legs are 2mm apart
at the apex and 6mm apart at the base when it is expanded
in the vena cava (Figure43.4). Due to its high patency rate,
this lter has been placed above the renal veins in patients
with thrombosis to the level of the renal veins. It has also
been placed in the SVC in rare circumstances. e lter was
originally designed for placement by operative technique by
way of the internal jugular or femoralveins.
e largest clinical experience was reported by
Green eld and Michna; 469 patients were followed for
55
12years,
with a long-term patency rate of 98%. e study
also showed a failure to insert the lter in 0.6% of patients,
misplacement of the lter in 2.5%, tilt of the lter in 1.7%,
proximal migration in 0%, venous stasis in 5%, and a recurrent PE rate in 4%. Other studies con rm and support these
56,57
ndings.
Similar results have been obtained in other follow-up
series, with long-term patency rates in excess of 95%. e
20-year experience demonstrated the same low rate of
recurrent PE and high rate of caval patency as seen in ear-
58
lier reports.
e results of suprarenal lter placement are
very comparable, with a 100% long-term patency rate in the
twenty-two patients studied in the series of sixty-nine lters
59,60
placed at this level since 1976.
TITANIUM GREENFIELD FILTERS
e titanium Green eld lter (Boston Scienti c, MA;
Figure 43.4) is made of titanium alloy. Its cone shape is
similar to that of the stainless steel Green eld lter, but it is
8mm wider at the base and 0.5cm taller. It weighs 0.25 g, as
opposed to 0.56 g for the stainless steel Green eld lter, and
54
it can be compressed to a diameter of 0.144inch.
A recurved hook design with an 80-degree angle will
serve as a barrier to penetration beyond the axis of the limb
and should limit both upward and downward vectors of
60
force that might induce migration.
e mechanical properties of the titanium Green eld lter have been tested
extensively, and it shows a remarkable resistance to exion
fatigue and induced corrosion. e titanium Green eld lter requires a 12 Fr carrier system and an introducer sheath of
14 Fr. is reduction in size of the overall system has led to a
reduction in insertion site venous thrombosis. Placement of
the titanium Green eld lter requires a guide wire inserted
percutaneously or by way of cutdown in the right jugular or
femoral vein over which a dilator system and attached 14-Fr
sheath are passed. When the dilator and sheath are in the
IVC at the desired level, the dilator is removed. e titanium Green eld lter carrier system is then placed through
the sheath with uoroscopic guidance. Both the sheath and
carrier are retracted as a unit to release the lter. e carrier
and sheath are removed and gentle pressure is applied to the
insertion site to promote hemostasis. is design reduces
premature mis re, which would place the lter in the sheath
rather than in the patient. Anew control handle that allows
no manipulation other than retraction of the carrier for discharge of the lter decreases the risk of premature discharge.
e lter is also preloaded into the carrier system, which
decreases the concern of crossedlimbs.
e behavior of the titanium Green eld lter seems
comparable to the stainless steel Green eld lter with
increased corrosion resistance and tolerance to exion
stress. In addition, because of its decreased carrier size, both
entry and positioning have been facilitated, and bleeding
during percutaneous lter insertion has been eliminated.
PERMANENT VENA CAVA FILTERS • 357
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