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9 Springer-Verlag New York, Inc. 2001
Cardiovasc Intervent Radiol (2001) 24:42-48
DOI: 10.1007/s00270001658
Mechanical Thrombectorny in Patients with Deep Venous Thrombosis Maxence Delomez, 1 Jean-Paul Beregi, 2 Serge Willoteaux, 2 Jean-Jacques Bauchart, 1 Bertrand Janne d'Othee, 2 Philippe Asseman, 1 Nessim Perez, 2 Claude Thery 1 lIntensive Care Unit, H6pital Cardiologique, Boulevard du Professeur Leclerq, F-59037 Lille Cedex, France 2Department of Vascular Radiology, H6pital Cardiologique, Boulevard du Professeur Leclercq, F-59037 Lille Cedex, France
Abstract Purpose: To report our experience with mechanical thrombectomy in proximal deep vein thrombosis (DVT). Methods: Eighteen patients with a mean (__+ SD) age of 37.6 __- 16.1 years who presented with DVT in the iliac and femoral vein (n = 3), inferior vena cava (n = 5), or inferior vena cava and iliac vein (n = I0), were treated with the Amptatz Thrombectomy Device after insertion of a temporary caval filtel. Results: Successful recanalization was achieved in 15 of 18 patients (83%). Overall, the percentage of thrombus removed was 66 +- 29%: 73 --- 30% at caval level and 55 36% at iliofemoral level. Complementary interventions (seven patients) were balloon angioplasty (n = 2), angioplasty and stenting (n = 2), thrombo-aspiration alone (n = I), thrombo-aspiration, balloon angioplasty, and permanent filter (n = 1)o and permanent filter alone (n = 1). There was one in-hospital death. Follow-up was obtained at a mean of 29.6 months; three patients had died (two cancers, one myocardial infarction); 10 had no or minimal sequelae; one had post-phlebitic limb. Conclusion: Mechanical thrombectomy is a potential therapeutic option in patients presenting with proximal DVT. Key words: Thrombectomy--Deep vein thrombosis--Pulmonary embolism Deep vein thrombosis (DVT) of the lower limbs is associated with considerable mortality and morbidity. In the United States, DVT is responsible for 300,000 hospital admissions and results in 50,000 deaths each year due to pulmonary embolism [1 ]. Treatment of DVT aims to prevent pulmonary embolism and post-phlebitic syndrome. Conventional medical treatment comprises unfractionated heparin or low-molecular-weight heparin followed by oral Correspondence to: J.-P. Beregi, M.D.; e-mail:
[email protected]
anticoagulation [2]. The role of anticoagulation therapy is to prevent complications such as pulmonary embolism, limit propagation of the thrombus, and diminish the risk of recurrence. Anticoagulation has no direct lytic effect and does not completely eliminate the formation of new thrombus [3]. Furthermore, some DVTs, in particular in the iliac veins or in the inferior vena cava, have an especially high risk of pulmonary embolism and of post-phlebitic syndrome with important socio-economic consequences [4]. Due to the shortcomings of anticoagulant treatment, alternative methods have been proposed: surgical treatment, systemic or in situ administration of thrombolytic drugs, or mechanical removal of the thrombus, Surgical treatment options, including embolectomy using a Fogarty catheter, venous bypass, or temporary creation of an arteriovenous fistula, give very variable results [5-7]. Systemic thrombolysis results in a higher venous patency rate than heparin. However, the long duration of the thrombolysis and the high doses required give rise to a risk of hemorrhage 3 - 4 times greater than that for heparin [8]. In situ thrombolysis has been utilized for some cases of recent and symptomatic proximal thrombosis [9, 10]. Mechanical thrombectomy is a novel technique, which by mechanically reducing the burden of thrombus might be of use in reducing the risk of pulmonary embolism and/or the occurrence of post-phlebitic leg in patients with extensive proximal DVT [11, 12]. The aim of the present report is to describe the immediate and mid-term outcome in a consecutive series of patients with DVT who were treated by mechanical thrombectomy using the Clot Buster Amplatz Thrombectomy Device (ATD, Microvena, White Bear Lake, MN, USA), a new recirculation device developed to mechanically macerate thrombus.
Materials and M e t h o d s Patients Patients were eligible for inclusion in the protocol if they had caval thrombus that was considered, by the referring clinician, to present
M. Delomez et al.: Mechanical Removal of Venous Thrombi
Fig. 1. The Clot Buster Amplatz Thrombectomy Device catheter and accessories. The ATD catheter is driven by compressed air controlled by a foot pedal. The system is prevented from heating up by means of continuous perfusion of cold saline solution under pressure.
a high risk of pulmonary embolism or if they had extensive iliocaval or iliofemoral thrombus that compromised lower-limb blood flow. Mechanical treatment was attempted only after failure of conventional medical treatment with unfractionated heparin for at least 48 hr. Patients with known or suspected pulmonary embolism were excluded, as the risk of a~gra,,,v-atm=" ,, or provokin,,~ puhnonary embolism with this device was unknown. The Ethics Committee of the University of Lille approved the study protocol. Eighteen patients (8 men) with a mean ( • SD) age of 37.6 • 16. I years were treated. The thmmbi were located in the iliac and femoral veins (n = 3), the inferior vena cava (n = 5). and the inferior vena cava and the iliac veins (n = 101. Risk factors for venous thrombosis included neoplasia (n = 3), coexisting inflammatory disease (n = 2/, surgery or recent childbirth, or a hypercoagulable state (n = 4); four cases occurred in women who smoked and were taking oral contraceptives. No predisposing factors were identified in five cases. The average age (time from the onset of lower limb symptoms or signs suggestive of DVT) of the thrombi was 45.3 • 76.3 days (range 4 - 2 4 0 days). Three patients had old ( > 2 months) thrombi, and the procedure was attempted as a result of signs suggesting additional recent thrombosis. Excluding these three patients, the a,,e= of the thrombi was I 1.3 _+ 6.9 days (range 4 - 2 8 days).
Thrombectomy Device The ATD catheter used comprised a double inverted helix rotating at 150,000 revolutions per minute in a protective sleeve. Its external diameter was 2.7 mm (8 Fr) with two lengths of 50 and 120 cm. It has no central aperture and is therefore not introduced over a guidewire. It is driven by compressed air (5 liter cylinder, 200 bars) controt/ed by a toot peda! (working pressure 5 - 6 bars). The system is prevented from heating up by means of continuous perfusion of cold saline solution under pressure (Fig. I). The rapid rotation of the helixes gives rise to negative pressure in the catheter (vortex effect), which sucks the clot inside the distal end, macerates it and recirculates the slurry via three side ports (Fig. 2). Unlike other mechanical thrombectomy systems, blood or thrombotic material is not removed from the circulation. The ATD has been authorized by
43
Fig. 2. Magnified view of the tip of the Clot Buster Amplatz Thrombectomy Device catheter with a schematic illustration of the interior (inverted double helix rotating at 150,000 revolutions per minute operated by compressed air). the Food and Drug Administration for the treatment of thrombotic dialysis shunt occlusions.
Procedural Derails A temporary t a r a [ filtcr (Fifterthery: Prothia. Montrouge, France) was advanced via the right brachial vein to tile inferior vena cava and positioned above the thrombus as prophylaxis against pulmonary embolism. An 8 Fr sheath (12-30 cm hmg) was inserted through the ipsilateral femoral vein in patients with th,ombosis confined to the vena cava and/or the iliac veins (n = 10); in patients (n = 5) with complete thrombosis of the iliofemoral venous system on one side with floating caval clot, the contralateral femoral vein was used. as the popliteal vein on the side with iliofemoral thrombosis was also thrombosed in all five patients. In these five patients, only the caval segment was treated, tn patients (Jr = 3) with isolated iliofcmoral thrombosis the ipsilateral popliteal vein was used. After baseline venography, through the introducer sheath, the ATD was advanced until the distal end was 2 cm fi'om the thrombus; it was then activated and advanced slowly while exerting a gentle rotational movement. After the device had been operated for 3 0 - 6 0 sec, repeat venography was performed. If significant thrombus (thrombus involving > 50% of the target vessel diameter) and/or failure to restore vein patency persisted, additional pa~ses were carried out. A maximum of one bottle of compressed air was used. Additional procedures, such as balloon angioplasty, thrombolysis, or stenting, were permitted at the discretion of the operator. At the end of the procedure, venography of the interior vena cava and an anteroposterior pulmonary angiogram, with the catheter in the main pulmonary artery, were performed.
Periprocedural Medication and Surveillance All patients were treated with therapeutic doses of unfractionated heparin (bolus of 100 1U/kg followed by an infusion adjusted to
44
M. Delomez et al.: Mechanical Removal of Venous Thrombi
Table 1. Technical details and procedural results Patient no.
Age/sex
Zone treated
ATD duration (min)
Total duration (min)
Procedural outcome
Complementary. procedures
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
48/F 74/F 43/M 21/F 42/M 19/M 24/F 28/F 34/F 45/F 24/F 28/F 35/M 3 I/M 40/M 17/F 59/M 65/M
IVC IVC IVC IVC IVC IVC-CI IVC-CI IVC-CI IVC-CI IVC-CI IVC-CI IVC-CI [VC-CI IVC-CI IVC-CI CI-EI-CF-SF EI-CF-SF CI-EI-CF
15 3 3 5 6 4 3 16 2.5 10 10 3 5 5 5 10 10 10
150 40 40 60 60 90 40 170 50 60 60 40 60 150 105 210 1l0 120
Success Success Success Success Success Failure a Success Failure Success Failure Success Success Success Success Success Success Success Success
PF
TA-PTA-PF PTA
TA PTA PTA-Stent PTA-Stent
M = male; F = female; IVC = inferior vena cava; EI = external iliac vein; CI = common iliac vein; CF = common femoral vein; SF = superficial femoral vein; PF = permanent caval filter; PTA = percutaneous angioplasty; TA = Thrombo-aspiration "Less than 50% of thrombus removed overall, with success at IVC level.
achieve an activated clotting time between 3 and 4 times the control value) tbr at least 48 hr before the procedure. Coagulation status was checked just before the procedure and the dose of heparin adjusted if required. Heparin infusion was continued during the procedure. A cavogram was performed 2 4 - 4 8 hr alter the procedure before removal of the temporary filter. Oral anticoagulation (heparin) was administered for at least 3 months. Arterial blood pressure, arterial oxygen saturation, and heart rate were monitored during the procedure. After the procedure, monitoring was continued in the intensive care unit until sheath removal. Serial electrocardiograms were performed and blood sampling for haptoglobin levels was performed.
positioning o f the d e v i c e r e q u i r e d t 5 - 3 0 min. T h e A T D d e v i c e was successfully positioned and activated in all cases. In three cases, the coupling b e t w e e n the helix and the turbine broke and a second d e v i c e was used. In five cases, portions o f the thrombus e m b o l i z e d into the caval filter during mechanical t h r o m b e c t o m y ; these w e r e successfully r e m o v e d by a d v a n c i n g the d e v i c e to the level o f the filter. The mean n u m b e r o f A T D passes was 2 -+ 1; the total duration o f m e c h a n i c a l t h r o m b e c t o m y was 7.0 -+ 4.2 rain. The total duration of the procedure, i n c l u d i n g the c o m p l e m e n t a r y interventions (described below), was 92 + 53 rain.
Definitions
Primary Success
Primary success was defined as the restoration of vein patency at the end of the procedure with removal of 50% or more of the thrombus burden as judged by analysis of the venograms before and after the procedure. The mean percentage of thrombus removed was assessed visually by comparing the venogram obtained after the last ATD pass with the baseline venogram.
Follow-Up The short-term patency of the treated sites was assessed before hospital discharge by helical CT angiography, conventional venography, or color Doppler ultrasound. Subsequent follow-up was obtained at outpatient visits or from the referring physician and/or the patients. All surviving patients had color echo Doppler ultrasound performed by the referring physician at least 6 months after the initial procedure.
Results T h e m a j o r results are presented in T a b l e 1. Insertion o f the caval filter and the v e n o u s sheath, baseline v e n o g r a p h y , and
Primary success (Table 2) was a c h i e v e d in 15 o f 18 (83%) patients; the success rate at the inferior vena c a v a level was 13 o f 15 (87%) and at iliac vein level was 9 o f 13 (69%). The failures occurred in the three patients with longstanding s y m p t o m s (estimated clot age 70, 200, and 240 days), in w h o m the procedure was a t t e m p t e d because of recent recurrent l o w e r - l i m b s y m p t o m s or signs.
Extent of Thrombus Removed T a b l e 2 presents the detailed results o f the p r o c e d u r e s in relation to the site(s) treated. O v e r a l l , the m e a n p e r c e n t a g e of t h r o m b u s r e m o v e d was 66 _+ 29%. In the five patients treated only at caval level, the m e a n percentage o f thrombus r e m o v e d was 78 + 23%. T h e v e n o g r a m s o f one o f the patients with isolated caval i n v o l v e m e n t are s h o w n in Figure. 3. In the three cases o f isolated iliofemoral thrombosis, the m e a n percentage of t h r o m b u s r e m o v e d was 60 +_ 17%. In the 10 patients treated at both iliac and c a v a l level, the
M. Delomez et al.: Mechanical Removal of Venous Thrombi
Table 2. Angiographicresults immediately after mechanical thrombectomy Patient
Percentage of thrombus removed
no.
1
2 3 4 5 6 7 8 9 I0 11 12 13 14 15 16 17 18
Overall
inferior vena cava
I~iac vein
100 80 50 60 t00 40 55 30 100 0 90 55 100 50 lOO 50 80 50
100 80 50 60 100 80 80 30 100 0 90 80 100 50 i00 NA NA NA
NA NA NA NA NA 0 30 30 100 0 90 30 100 50 I00 50 80 50
NA = not applicable.
mean percentage of thrombus removed was 62 --- 35%. The venograms of one of the patients with iliofemoral involvement are shown in Figure 4. When analyzed as a function of the vein segment treated, 73 --- 30% of thrombus was removed at caval level (5 isolated caval thrombi and the caval portion of the 10 iliocaval thromboses). At the iliofemoral level (3 isolated iliofemoral thromboses and 10 iliofemoral thromboses associated with caval thrombi), the percentage of thrombus removed was 55 + 36%.
Complementary Procedures Complementary procedures were performed in seven patients. In two patients, with interior vena cava thrombosis that extended proximal to the renal veins, the vena cava was treated in order to implant an infrarenal permanent filter. In one of these patients the filter was implanted immediately after mechanical thrombectomy (Fig. 5); in the second, thrombo-aspiration of residual floating thrombus was performed through the introducer sheath using simple suction, followed by balloon angioplasty of the lilac vein, before implantation of the filter. A third patient had thrombo-aspiration of residual floating thrombus through the introducer sheath using simple suction, with no further intervention. The remaining four patients were treated by balloon angioplasty alone (n = 2) or balloon angioplasty followed by stent implantation (n = 2) as the venogram after thrombectomy showed residual lilac stenoses. Two covered stents (Cragg-EndoPro System 1, Mintec, Marseille, France), 10 mm in diameter and 6 and 10 cm long, were implanted in one of these patients: stent implantation was performed to treat a suspected Cockett's syndrome; covered stents were used in an attempt to exclude residual mural thrombus from the
45
lumen. The stents were occluded 24 hr later. The indication for stenting in the second stented patient (Fig. 4) was external compression of the vein due to a neoplasm. This patient had three stents implanted: two Wallstents (Schneider, Minneapolis, MN, USA) 12 and 14 m m in diameter and 68 mm long, and a single Memotherrn (Bard, Murray Hill, NJ, USA) stent 10 rnm in diameter and 70 mm long, inserted in the c o m m o n femoral vein to the level of the inferior vena cava; these were patent at 1 month follow-up.
Complications During the mechanical thrombectomy procedures, all the patients developed transient arterial desaturation. The baseline saturation, while breathing room air, was > 95% in all patients. This decreased dunng operation of the thrombectomy device (minimum 65% in one patient). These episodes were symptomatic in seven patients, who described dyspnea and a feeling of anxiety. In all cases, saturation returned to normal in < 1 min when operation of the device was discontinued. No evidence of pulmonary embolism was seen on the anteroposterior pulmonary angiograms performed at the end of the procedure. Multiple projections were not performed in order to limit the dose of contrast. No patient developed anemia or other signs suggestive of hemolysis. One patient developed a transient increase in haptoglobin with no clinical consequences.
Short-Term Results Patients underwent helical CT angiography, ilio-cavography, or echo Doppler ultrasound at a mean of t0.7 _ 1 1.7 days after the procedure. In the 13 patients with successfully treated vena caval thrombus, the initial result was maintained in all but one; this patient developed recurrent caval thrombosis, probably related to a local compressive etiology, which resulted in the death of the patient by extension to the renal veins with acute renal failure. An underlying neoplasm was suspected clinically in this Patient but the family refused an autopsy. In the 11 patients treated successfully at iliofemoral level, five reocclusions occurred within the first 48 hr; three were at iliac level and two at femoral level.
Mid-Term Results All 14 patients who had successful procedures without inhospital complications were followed for a mean o f 29.6 months. All were treated with oral anticoagulants for a minimum of 3 months. In all the patients who had successful procedures without in-hospital complications, and who were alive at 6 months, color echo Doppler ultrasound, performed by their referring physician, confirmed continuing patency of the treated segments. Three patients died during follow-up, one from myocardial infarction and two from cancer (one
46
M. Delomez et al.: Mechanical Removal of Venous Thrombi
Fig. 3. A Occluded vena cava at baseline. 13 Final result after thrombectomy performed as a stand-alone procedure.
9
!L!,,c P0sr:
Fig. 5. A Baseline angiogram showing complete occlusion of the inferior vena cava with a well-developed collateral circulation via the azygos network. B The final result after thrombectomy with implantation of a permanent caval filter just distal to the renal veins.
ultrasound evidence of recurrent puhnonary embolism or of recurrent DVT. Ten of the I I remaining patients had no or only minimal symptoms (grade 0 or 1, according to the classification proposed by Kakkar and Lawrence [131); one had significant sequelae (grade 4) with venous ulceration.
Discussion
ip 9 ~ i ~
84
9
Fig. 4. A Thrombus in the left lilac and femoral venous system before treatment. The ATD catheter was introduced via a popliteal approach (B), and subsequently, adjunctive stenting (C) was performed. D Result 48 hr after mechanical thrombectomy and stenting, performed using an ipsilateral popliteal approach.
pre-existing, one newly diagnosed in a patient treated at vena caval level who was readmitted with unilateral lower limb DVT 18 months later). No other patients had clinical or
Conventional medical treatment of thromboembolic disease, with intravenous heparin followed by oral anticoagulants, does not consistently eliminate thrombus from the deep vein network. Thrombolysis is more effective but is associated with a greater risk of bleeding [8]; mechanical thrombectomy is therefore an attractive approach to the treatment of DVT. Several mechanical approaches to DVT have been proposed, involving clot removal by fragmentation and/or suction [ 14-16]. The initial experimental and clinical results are encouraging and this approach may replace or complement traditional therapy [17-19]. Furthermore, mechanical thrombectomy could be used in conjunction with other endovascular techniques, such as thrombo-aspiration and local fibrinolysis. The presence of underlying anatomic lesions,
M. Delomez et al.: Mechanical Removal of Venous Thrombi
such as Cockett's syndrome, generally requires complementary angioplasty or stenting [20-23]. There are few studies relating to the efficacy of the thrombectomy device used in the present study for venous thrombus [10, I l]. However, several studies have confirmed the feasibility and efficacy of the device in the treatment of thrombi in the arterial system and in arteriovenous dialysis fistulae [18, 19]. In contrast to the situation with arterial pathology, it is more difficult to determine the age of the thrombus in patients with DVT. The ATD seems to be particularly effective when the thrombus is relatively recent (less than 15 days). Furthermore, even in patients with old thrombus, who develop superimposed new thrombus, the proximal extent of the thrombus may be sensitive to mechanical thrombectomy; in the present study, some caval extensions of iliofemoral thrombosis were treated in such patients using a contralateral approach. Our results were particularly impressive in cases of vena caval clot. The larger caliber of the inferior vena cava and the higher flow rate may explain the more favorable initial and long-term results at the coral level, where reocclusion occurred in only one patient. In contrast, at the level of the lilac and femoral veins, reocchtsion was more frequent. As already reported, we tbund that, at the lilac level, underlying anatomic abnormalities that require supplementary angioplasty and/or stenting may exist [21, 23f. While thrombectomy can be used to restore the blood flow, parietal thrombi often persist and may predispose to recurrent occlusion. Conversely, even partially successful thrombectomy may transtbrm an occlusive thrombus into a nonocclusive thrombus, which is known to be more sensitive to drug treatment [241. The optimal complementary therapeutic approach alter mechanical thrombectomy remains to be clarified, as does the optimal drug treatment during and alter the procedure (effective anticoagulation, fibrinolysis, anticoagulant and/or antiplatelet agents). We used an 8 Fr device, which allowed efficient thrombus removal without bleeding complications. The ATD is quite a flexible device and relatively atraumatic, even in the venous circulation, although it has the potential to cause subclinical vascular damage [25]. However, the device is fragile; in our early experience, several catheters malfunctioned, due to excessive bending of the body of the catheter; subsequently, no such problems were encountered. Although more than 95% of the particles produced by the device are < 15 ~zm in size, larger thrombi may migrate into the pulmonary arteries [26]. Arterial desaturation is common and may be due to vasoconstriction in the pulmonary circulation due to the release of serotonin or other vasoactive agents after mechanical disruption of the thrombus. However, in the present study such effects were transient and devoid of clinical consequences. The recommended technique of thrombectomy includes the recommendation that the leading (proximal) part of the thrombus be left untreated in order to minimize the risk of pulmonary embolism; how-
47
ever, this approach is difficult in practice. Thus, as already reported, the use of protection by means of a temporary caval filter seems to us to be essential in this context [12, 27-29]. This hypothesis is supported by the fact that, in five patients, there were numerous thrombi in the filter after the procedure. These were easily treated by passing the ATD into the filter. The use of the device in the temporary filter was not associated with complications; however, caution is advised as the use of the Amplatz device in the vicinity of an endoluminal graft has resulted in malfunction of the device and difficulty in withdrawing it from the circulation [30]. We do not have sufficient data to be able to evaluate the efficacy of the ATD in the long term. Although controversial, there is suggestive evidence that re-establishing vein permeability reduces the long-term sequelae [31-33]. The ATD can be used to re-establish proximal vein patency with infrequent adverse effects. Conversely, with this type of procedure, the more distal vein networks (popliteal and subpopliteal) remain thrombosed. At the present time, permanent filters are often considered in patients with large free-floating thrombi which, intuitively, have been associated with a higher risk of pulmonary embolism. However, a randomized study has concluded that permanent filters should be employed with caution in such patients [34]. Mechanical thrombectomy, by removing the major proximal part of the thrombus, may represent an alternative strategy in such patients.
Study Limitations The major limitation of the study is the relatively small number of patients studied. Future studies are required to establish the role of thrombectomy in the management of DVT, to determine whether thrombectomy may play a role in the prevention of puhnonary embolism in selected patients, and to determine the optimal adjunct pharmacologic and/or mechanical therapy. In conclusion, the Clot Buster Amplatz Thrombectomy Device catheter provides an alternative option for the treatment of recent proximal DVT. It is safe and effective when used in conjunction with a temporary coral filter. This method seems to be particularly effective for caval clot. At the iliofemoral level the risk of reocctusion appears to be higher and complementary procedures may be required. Furthermore, the optimal adjunctive pharmacologic treatment (anticoagulants, antiplatelet agents, etc.) requires further investigation.
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