Page 2378 - Hematology_ Basic Principles and Practice ( PDFDrive )

2120 Part XII Hemostasis and Thrombosis

with severe PTS, with or without ulcers, should consider consulting
a venous endovascular specialist.

Inferior Vena Cava Filters

IVC filters are indicated for patients with proximal DVT or PE who
have contraindications to or complications of anticoagulation, who
develop symptomatic PE despite therapeutic-level anticoagulation,
and/or who have severe cardiorespiratory compromise. In other cir-
cumstances, caution should be used when placing IVC filters because
of ongoing uncertainty about their long-term risk–benefit ratio. Two
randomized trials evaluating IVC filters are worthy of note. In the
PREPIC Study, which was carried out in patients concomitantly
receiving anticoagulant therapy and which was underpowered to
detect an effect on fatal PE, filters appeared to provide additional
30
protection against symptomatic PE but did not alter mortality.
Symptomatic recurrent DVT was increased in the filter group, but
the overall rates of PTS and symptomatic recurrent VTE did not
differ significantly. Because fatal PE rarely occurs in patients with
DVT who are properly anticoagulated, IVC filters should not be
routinely placed in patients with DVT. Patients who experience
clinical failure of first-line anticoagulation can usually be switched to
an effective alternative regimen, such as LMWH or another oral
anticoagulant.
Retrievable IVC filters have the intended advantages of allowing
PE prophylaxis during the period of highest risk, with subsequent
removal thereafter. However, it should be noted that the stability and Fig. 143.4 ILLUSTRATING THE COMPLEXITIES OF DETERMIN-
mechanical integrity of retrievable devices do not yet match those of ING WHETHER INFERIOR VENA CAVA (IVC) FILTERS ARE OF
older filters designed for permanent implantation, and many cases of BENEFIT OR NOT. A digital subtraction venogram shows a large globular
retrievable filter migration have been reported. Therefore if there is a filling defect within an IVC filter that was placed 3 days ago. Filter proponents
strong likelihood that permanent IVC filtration will be needed, it is might argue that this represents a large, potentially fatal pulmonary embolism
best to select a permanent, nonretrievable IVC filter device. In DVT trapped within the filter, while filter opponents might argue that this is a case
patients with a time-limited indication for an IVC filter, placement of filter-induced IVC thrombosis, a major complication. Who is right?
of a retrievable IVC filter is reasonable. However, it is important that
the need for the IVC filter be reassessed every few weeks after place-
ment so that the filter can be removed when it is no longer needed. collaboration between internists and endovascular physicians is
Although many filters are placed with the intent to be retrieved, less needed to ensure optimal patient care.
than 50% are removed. Consequently physicians must monitor
patients with these devices to ensure that they are removed when
appropriate. REFERENCES
The recently completed PREPIC-2 study was a multicenter RCT
that evaluated the use of retrievable IVC filters for the prevention of 1. Vedantham S, Thorpe PE, Cardella JF, et al: Quality improvement
recurrent PE in hospitalized patients with acute PE and clinical fea- guidelines for the treatment of lower extremity deep vein thrombosis
31
tures deemed to pose high risk for recurrence or death. This study with use of endovascular thrombus removal. J Vasc Interv Radiol 17:435,
did not identify a clinical benefit from IVC filter placement, either 2006.
in terms of mortality or recurrent symptomatic PE. Hence a compel- 2. Rajan DK, Patel NH, Valji K, et al: Quality improvement guidelines for
ling justification should be present to support placement of IVC percutaneous management of acute limb ischemia. J Vasc Interv Radiol
filters in VTE patients who are eligible to receive anticoagulant 20:S208–S218, 2009.
therapy. 3. Engelberger RP, Spirk D, Willenberg T, et al: Ultrasound-assisted versus
At a health care system level, better studies of the use of IVC conventional catheter-directed thrombolysis for acute iliofemoral deep
filters in different clinical scenarios should be considered an urgent vein thrombosis. Circ Cardiovasc Interv 8:e002027, 2015.
priority because the devices are being used more frequently. The 4. Schrijver AM, van Leersum M, Fioole B, et al: Dutch randomized trial
balance between PE prophylaxis and the long-term risks of IVC comparing standard catheter-directed thrombolysis versus ultrasound-
filter placement is complex and deserves more rigorous evaluation accelerated thrombolysis for arterial thromboembolic infrainguinal
(Fig. 143.4). disease. J Endovasc Ther 22(1):87–95, 2015.
5. Donaldson CW, Baker JN, Narayan RL, et al: Thrombectomy using
suction filtration and veno-venous bypass: single-center experience with
CONCLUSION a novel device. Catheter Cardiovasc Interv 86:E81, 2015.
6. Cynamon J, Stein EG, Dym J, et al: A new method for aggressive
Imaging-guided endovascular interventions have evolved significantly management of deep vein thrombosis: retrospective study of the power
over the last 25 years and now offer the potential for improved patient pulse technique. J Vasc Interv Radiol 17:1043–1049, 2006.
outcomes in several disease states. For PAO, randomized trials have 7. O’Sullivan GJ, Lohan DG, Gough N, et al: Pharmacomechanical
defined the role for CDT for the treatment of acute limb ischemia. thrombectomy of acute deep vein thrombosis with the Trellis-8 isolated
For DVT, a robust body of preliminary research and one randomized thrombolysis catheter. J Vasc Interv Radiol 18:715–724, 2007.
trial support the potential for catheter-based thromboreductive thera- 8. Dormandy J, Heeck L, Vig S: Acute limb ischemia. Semin Vasc Surg
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appropriate patients are selected for intervention. Multidisciplinary peripheral arterial ischemia. J Vasc Surg 19:1021–1030, 1994.