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(Radiology. 2000;217:678-684.)
© RSNA, 2000

Vascular and Interventional Radiology

Hydrodynamic Thrombectomy System versus Pulse-Spray Thrombolysis for Thrombosed Hemodialysis Grafts: A Multicenter Prospective Randomized Comparison1

Klemens H. Barth, MD, Mark R. Gosnell, BS, Aubrey M. Palestrant, MD, Louis G. Martin, MD, Jeffrey B. Siegel, MD, Terence A. S. Matalon, MD 2, Scott C. Goodwin, MD, Paul A. Neese, MD, Timothy L. Swan, MD and Renan Uflacker, MD

1 From the Department of Radiology, Georgetown University Medical Center, Washington, DC (K.H.B.). Affiliations for all other authors are listed at the end of this article. From the 1998 RSNA scientific assembly. Received October 11, 1999; revision requested November 23; revision received February 1, 2000; accepted February 23. Financial support and disclosure statements appear at the end of this article. Address correspondence to K.H.B., 6405 Hillmeade Rd, Bethesda, MD 20817.


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
PURPOSE: To evaluate the safety and efficacy of a hydrodynamic thrombectomy system in a prospective, multicenter randomized comparison with pulse-spray thrombolysis in hemodialysis grafts.

MATERIALS AND METHODS: Nine centers enrolled 120 adult patients with recently (<=14 days) thrombosed hemodialysis grafts. Graft venography was used to confirm occlusion in 62 patients randomly assigned to thrombectomy and 58 to thrombolysis. For thrombolysis, a mixture of 5,000 U of heparin and 250,000 U of urokinase was distributed throughout the thrombus, first to the venous then to the arterial graft end. For thrombectomy, the catheter was passed in the same sequence. Technical success was removal of 80% or more of thrombus. Clinical success was technical success plus the ability to dialyze. Also assessed were total procedure time, thrombus treatment time, procedure-related blood loss, other complications, and 30- and 90-day outcomes.

RESULTS: Patient demographics were comparable. Technical success rates were 95% (59 of 62) for thrombectomy and 90% (52 of 58) for thrombolysis (P = .31). Clinical success rates were 89% (55 of 62) and 81% (47 of 58), respectively (P = .24). At 30 days, 69% (43 of 62) and 66% (38 of 58), respectively, could be dialyzed through the graft (P = .70); at 90 days, the rates were 40% (25 of 62) and 41% (24 of 58), respectively (P = .91). None of these differences or those for procedure-related blood loss and early and late complications were statistically significant. Thrombus treatment times of 16.8 minutes for thrombectomy and 23.4 minutes for thrombolysis were significantly different (P < .01).

CONCLUSION: The hydrodynamic thrombectomy system is at least as efficacious and safe as pulse-spray thrombolysis but shortens thrombus treatment time.

Index terms: Dialysis, 81.42 • Efficacy study • Grafts, interventional procedures, 91.1265, 91.1269 • Grafts, stenosis or thrombosis, 91.751 • Thrombectomy, 91.1269 • Thrombolysis, 91.1265


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Maintaining durable hemodialysis access is a life-sustaining measure for patients with end-stage renal disease. Many patients will have a surgically placed arteriovenous shunt graft, which has a limited durability and fails most often owing to stenosis of the venous outflow (1). Percutaneous recanalization of thrombosed grafts combined with percutaneous transluminal angioplasty of the venous outflow has become the technique of choice in many institutions (2–6).

Until recently, pharmacomechanical thrombolysis, or pulse-spray thrombolysis, was the dominant percutaneous technique. Now several thrombectomy techniques have been introduced clinically or are in trials (4,7–14). They promise faster and more efficient thrombus removal, do not subject the patient to the risks of thrombolytic therapy, and apply also to those patients who are not candidates for lysis. Whereas thrombectomy may be performed simply by mechanical clot maceration with balloon catheters or with rotary devices, these instruments are limited to artificial grafts and could be traumatic to native veins (15–17). Hydrodynamic thrombus aspiration catheters that use the Venturi effect liquefy and remove the thrombotic material and should be much less traumatic to the vascular wall (8,11, 13,15,18–20). We tested such a catheter that uses a standard angiographic injector to create the self-contained saline solution jet. We evaluated its safety and efficacy against that of pulse-spray thrombolysis in a prospective, multicenter, randomized comparison.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Hydrodynamic Thrombectomy System
The entire hydrodynamic thrombectomy system (Oasis; Boston Scientific, Natick, Mass) consists of a three-lumen thrombectomy catheter, tubing for connection to an angiographic injector, and a collection bag with connection tubing (Fig 1). The catheter inflow lumen is connected to the injector, and the outflow lumen is connected to the collection bag. A three-way stopcock between the catheter connection and the injector allows quick refilling of the injector from a reservoir of heparinized physiologic saline solution (Fig 1).



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  		Figure 1. Physiologic saline solution is injected through the inflow lumen, emerges as a high-velocity jet from the curved catheter nozzle, and enters the outflow lumen. Thrombus is aspirated into the return by the Venturi suction effect. The collection bag stores returned saline solution and aspirated thrombus material.

 
The third catheter lumen is the guide-wire lumen. The injector syringe is filled from the saline solution reservoir. For operation, the injection pressure is 750–850 psi at the injection rate of 2.5 mL/sec. Once the system is vented, the final connection between the high-pressure connection tubing and the catheter is made. The system is tested for leak-free operation and evidence of saline solution return into the collection bag. Then the catheter is inserted through the introducer sheath into the graft. The injector is turned on to activate the system. The catheter is advanced slowly forward through the thrombus. The return of saline solution and liquefied thrombus material is carefully monitored to avoid excessive blood removal. Since no saline solution is actually injected into the graft, the excess volume in the collection bag over the volume supplied represents aspirated material.

Study Protocol
Nine participating institutions enrolled 120 adult patients during a period of 11 months (Table 1). All patients gave written informed consent after being completely informed about the nature of the research study, which had been approved by the institutional review board of each participating institution. Patient demographics, graft age, and the number of previous graft recanalizations are listed in Table 2. To be eligible for the study, each patient had to have a prosthetic graft that could not have been occluded for more than 14 days and could not be infected, and the patient had to be a candidate for lytic therapy according to the standard eligibility criteria for this treatment.


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  		TABLE 1. Investigational Sites and Patient Enrollment
 

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  		TABLE 2. Pretreatment Patient Demographics
 
Before treatment, all patients received 325 mg of acetylsalicylic acid orally. According to the common protocol, the graft was first examined for physical evidence of occlusion (ie, no pulse, no thrill). The venous graft limb was then entered to obtain a venogram to document graft occlusion. The amount of thrombus was estimated by measuring the graft length on the venogram, as well as the length of the graft filled with thrombus (clot length) (Table 2). The venous outflow was studied for evidence of stenosis or occlusion.

Venographic findings had no influence on inclusion into the study protocol. It was left to the individual investigator either to reopen the venous outflow first by means of standard percutaneous transluminal angioplasty technique and, if indicated, stent placement or to defer such treatment until after the graft was reopened. Then, two short 6-F introducer sheaths were placed, one downstream through the existing graft access, and the other in the opposite direction toward the arterial inflow as in the standard "crossed catheter" technique. Next, the patients were randomly assigned to pulse-spray thrombolysis or to thrombectomy with the hydrodynamic thrombectomy system.

Patients in the thrombolysis group had a multi–side-hole catheter inserted. Through this catheter, a mixture of 250,000 U of urokinase (5 mL; Abbokinase; Abbott Laboratories, North Chicago, Ill) and 5,000 U of heparin sodium (5 mL) in a 10-mL syringe was sprayed manually throughout the graft in approximately 0.2-mL increments every 30 seconds during forward movement of the catheter, first toward the venous then toward the arterial anastomoses. The same procedure could be repeated if there was more than 20% residual thrombus retained in the graft. Completion of lysis was documented by means of injecting contrast material. The arterial plug was then removed with an angioplasty balloon or a 4- or 5-F Fogarty catheter. If the plug remained inside the graft or venous outflow, it could be compressed against the wall by the Fogarty catheter or angioplasty balloon. Any remaining venous or graft stenosis was then dilated. At the completion of the procedure, a complete graft angiogram that included the venous outflow was obtained.

Patients in the thrombectomy group were given 2,000–3,000 U of heparin sodium systemically. The hydrodynamic catheter then was inserted through the introducer sheath either directly or over a 0.018-inch guide wire first toward the venous then toward the arterial graft end and activated while being slowly advanced and withdrawn. Several passes could be made until the operator determined by injecting contrast material that all thrombus had been removed or no further clot removal was possible. The arterial plug was then pulled, as described for thrombolysis, since the hydrodynamic catheter was not to cross the arterial anastomosis. The remainder of the procedure was identical to that for thrombolysis.

Technical success of either procedure was defined as no or up to 20% residual thrombus judged by the difference between the initial and the completion venograms. No crossover was allowed from thrombolysis to thrombectomy; however, crossover was allowed from thrombectomy to thrombolysis. Clinical success was defined as technical success with the assigned therapy plus the ability to dialyze after treatment. Primary patency was defined as graft patency maintained without additional treatment for graft thrombosis during the 90-day follow-up period.

The total procedure time was defined as the time from the initial graft access to completion venography. The thrombus treatment time was defined as the interval between onset of pulse spray urokinase infusion and catheter removal or from the activation of the hydrodynamic catheter to its removal. If more than one catheter introduction was made through either sheath, the times were added. In the thrombectomy group, the returned excess volume—the total volume in the collection bag minus the recirculated saline solution volume—was recorded. In addition, procedure-related blood loss was determined by comparing the preprocedure hematocrit levels with those obtained within 24 hours after the procedure. Also determined was the plasma-free hemoglobin level to check for potential hemolysis in the thrombectomy group.

Complications encountered were divided into acute events, which occurred within 48 hours after treatment, and late events, which occurred more than 48 hours after treatment. All deaths were recorded, whether directly related to the procedure or not. Also recorded were perforation of the graft or draining vein; blood loss or formation of a hematoma for any reason, whether or not it required surgical intervention or transfusion; and any symptomatic arterial or pulmonary embolism. Routine lung scanning to discover subclinical pulmonary emboli was not required by the protocol.

Statistical Analysis
Statistical evaluation for this two-arm randomized trial was performed on categorical data by using a {chi}2 test or a two-tailed Fisher exact test if the expected frequencies were small. The Student t test was used for comparisons of normally distributed continuous variables. For nonnormally distributed variables, the Wilcoxon rank sum test was used. All calculations were performed with commercially available statistical software (SAS software version 6.12; SAS Institute, Cary, NC). Paired values were considered significantly different when the P value was less than .05.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
DISCUSSION
 REFERENCES
 
Initial venography in all 120 patients revealed underlying venous stenosis in 106 patients (88%). Eighty-one patients (68%) had an anastomotic venous stenosis. Twenty-five patients (21%) had a proximal stenosis in the axillary, subclavian, or brachiocephalic vein, most often secondary to prior temporary central venous catheter insertion for hemodialysis. Other underlying causes of graft thrombosis were intragraft stenosis or pseudoaneurysm (30%); anastomotic, proximal, or distal arterial stenosis (23%); and no identifiable cause (15%). Forty-seven percent of patients had more than one underlying cause identified (Table 3). Intragraft stenosis was more frequent in the thrombectomy group (37%); arterial anastomotic stenosis was more frequent in the thrombolysis group (26%). Otherwise, the two groups were similar (Table 3). The length and caliber of the graft and the length of thrombus were similarly distributed among patients in both treatment groups (Table 2).


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  		TABLE 3. Underlying Causes of Graft Thrombosis
 
In the thrombolysis group, 50 patients received a total of 250,000 U of urokinase, six patients received up to 500,000 U, and two patients received up to 750,000 U. In the thrombectomy group, the volume of recirculated saline solution used was 295 mL on average (range, 60–1,000 mL).

The hydrodynamic catheter tracked smoothly over the guide wire, except in narrowly looped grafts where the stiff metallic catheter tip posed some resistance to advancement owing to friction between the metallic catheter tip and the guide wire (Fig 2). Therefore, some investigators found it easier at times not to use the guide wire.



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  		Figure 2a. (a) Initial posteroanterior graft venogram shows stasis of contrast agent and thrombus material as filling defects. Note the postanastomotic venous stenosis (arrow). (b) Posteroanterior venogram obtained during hydrodynamic thrombectomy shows the catheter as it is advanced toward the venous anastomosis over a 0.018-inch guide wire. Note the metallic catheter tip (arrow) and curved nozzle. (c) Posteroanterior venogram obtained during hydrodynamic thrombectomy shows the catheter as it is advanced toward the arterial graft anastomosis.

 


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  		Figure 2b. (a) Initial posteroanterior graft venogram shows stasis of contrast agent and thrombus material as filling defects. Note the postanastomotic venous stenosis (arrow). (b) Posteroanterior venogram obtained during hydrodynamic thrombectomy shows the catheter as it is advanced toward the venous anastomosis over a 0.018-inch guide wire. Note the metallic catheter tip (arrow) and curved nozzle. (c) Posteroanterior venogram obtained during hydrodynamic thrombectomy shows the catheter as it is advanced toward the arterial graft anastomosis.

 


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  		Figure 2c. (a) Initial posteroanterior graft venogram shows stasis of contrast agent and thrombus material as filling defects. Note the postanastomotic venous stenosis (arrow). (b) Posteroanterior venogram obtained during hydrodynamic thrombectomy shows the catheter as it is advanced toward the venous anastomosis over a 0.018-inch guide wire. Note the metallic catheter tip (arrow) and curved nozzle. (c) Posteroanterior venogram obtained during hydrodynamic thrombectomy shows the catheter as it is advanced toward the arterial graft anastomosis.

 
Technically successful graft recanalization was achieved in 59 (95%) of the 62 patients in the thrombectomy group and in 52 (90%) of the 58 patients in the thrombolysis group (P = .31). Clinical success was achieved in 55 (89%) of the 62 patients and in 47 (81%) of the 58 patients (P = .24) (Table 4). The mean underlying venous stenosis before percutaneous transluminal angioplasty was 76% ± 17 (SD) in the thrombolysis group and 82% ± 16 in the thrombectomy group. After angioplasty, it was reduced to 22% ± 22 in the thrombolysis group and 23% ± 24 in the thrombectomy group, which resulted in a mean stenosis reduction of 59% ± 24 in the thrombectomy group and 54% ± 27 in the thrombolysis group (P = .33).


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  		TABLE 4. Technical and Clinical Outcomes
 
The 30-day primary patency rate was 69% (43 of 62) for the thrombectomy group and 66% (38 of 58) for the thrombolysis group (P = .70). The 90-day rates were 40% (25 of 62) and 41% (24 of 58), respectively (P = .91). None of these differences between the two treatment groups was statistically significant.

Technical failures were encountered in six patients in the thrombolysis group. Four were due to more than 20% residual thrombus, but all could be dialyzed within 24 hours after adjunctive thrombectomy by means of an angioplasty balloon or a Fogarty catheter. All four could have been treated with the hydrodynamic thrombectomy system had crossover been allowed from thrombolysis to thrombectomy according to the common protocol. The other two patients required surgical graft revision, one because of an undilatable arterial inflow stenosis and the other because of a long, threadlike venous outflow stenosis. The three cases of hydrodynamic thrombectomy failure had more than 20% residual thrombus. Two crossed over to thrombolysis, which reopened one of the two; the other one had successful thrombectomy with a Fogarty catheter. The third patient required surgical graft revision. The difference between technical and clinical successes is explained primarily by early graft rethrombosis due to underlying graft abnormality or unsustainable inflow or outflow.

The mean total procedure times were not significantly different between the two techniques (Table 5). For the thrombectomy group, procedure time included setup and testing of the system, adding 10–15 minutes to the total time. However, the mean thrombus treatment time was significantly shorter for the hydrodynamic thrombectomy group than for the pulse-spray thrombolysis group (P < .01) (Table 5). Pre- and postprocedure hematocrit levels did not differ significantly between the two groups (P = .06) (Table 6). In several patients, however, up to 200 mL of blood was drawn into the collection bag during thrombectomy. This was in excess of the expected amount of liquefied thrombus material and is related to the lack of careful monitoring of the returned volume, as well as interim checks for completion of thrombectomy. No significant hemolysis was detected, as the postprocedure mean plasma-free hemoglobin level did not differ significantly from the preprocedure level.


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  		TABLE 5. Total Procedure and Thrombus Treatment Times
 

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  		TABLE 6. Estimated Blood Loss during Procedure
 
The complications recorded for both treatment groups are listed in Table 7. Among the acute events were three perforations that occurred during guide-wire manipulation at or near the stenosed venous anastomosis. Two were inconsequential (one in each group). In the third patient (thrombectomy group), this complication prevented reopening of the venous outflow, as contrast material extravasation made it impossible to identify the narrowed venous lumen, and rethrombosis of the graft occurred. Procedure-related bleeding occurred in four patients. One patient from the thrombectomy group developed a self-contained hematoma at the site of the venous percutaneous transluminal angioplasty. One patient from the thrombolysis group bled from a recent arteriotomy site. Another thrombolysis group patient whose access sheath was accidentally pulled out bled and required prolonged compression to obtain hemostasis. Access-site bleeding occurred in the fourth patient (thrombectomy group). One pulmonary embolization was documented in a patient with unsuccessful thrombectomy. In this patient, thrombus material was mobilized in the graft with a Fogarty catheter and pushed through the venous anastomosis. There were no clinical sequelae.


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  		TABLE 7. Complications
 
In the thrombectomy group, two arterial embolizations occurred. One event was discovered during reflux venography. No treatment was instituted. The other event occurred during removal of the arterial plug with a Fogarty catheter, when part of the plug dislodged into the brachial artery. Arterial thrombolysis was performed successfully. One such event in the pulse-spray thrombolysis group, which occurred during percutaneous transluminal angioplasty of the arterial anastomosis, was also successfully treated by means of arterial thrombolysis.

Delayed complications included three deaths. All occurred after hydrodynamic thrombectomy. None could be directly related to the procedure or device. One 56-year-old man died of sepsis 8 days after failed thrombectomy. He subsequently received a nontunneled transjugular hemodialysis catheter. Two days thereafter he became febrile, oral antibiotics were administered, and he was discharged from the hospital. Another 2 days later, he was readmitted with sepsis and developed multiorgan failure. A 73-year-old man died 20 days after thrombectomy of a myocardial infarction and sepsis secondary to a ruptured appendix. The third patient, a 74-year-old woman, died of a myocardial infarction 26 days after thrombectomy.


   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
REFERENCES
 
This multicenter study enlisted patients from a widespread geographic area, thereby in all likelihood representing a cross section of the patient population with occluded hemodialysis grafts. Patients who were selected for either treatment technique did not differ substantially in their demographic and other baseline data. This trial was designed primarily to establish the safety and efficacy of the hydrodynamic thrombectomy system by comparison with pulse-spray thrombolysis, which functioned as the control. On the basis of prior experience with similar thrombus aspiration devices and the results of nonrandomized trials with the current catheter, it was likely that this hydrodynamic thrombectomy system would be at least as effective as pulse-spray thrombolysis in removing fresh thrombus from hemodialysis grafts (12,21). It was also expected that the time to effectively remove the graft thrombus would be shorter than that with thrombolysis owing to the lack of dwell time (12,13, 21). Both expectations were met.

Since the study was randomized, each patient had to be a candidate for thrombolysis, which excluded patients with a history of recent stroke, transient ischemic attack, gastrointestinal bleeding, and coagulation deficits (22). None of these are contraindications to thrombectomy with the hydrodynamic thrombectomy system used in this study and other hydrodynamic or mechanical thrombectomy procedures.

Absent significantly (Table 7) higher complication rates for this hydrodynamic thrombectomy system, the most pertinent assessment of the two recanalization techniques is that of the initial technical success. Here, both showed similar results. Equally, the clinical results, which included the ability to perform hemodialysis after the graft had been reopened, showed a substantial decline in graft patency between both groups owing to graft rethrombosis, mostly caused by restenosis of the venous outflow. This is not surprising in a patient population with deteriorating arteriovenous grafts and is consistent with results of previous reports (12,14). Therefore, graft rethrombosis was not influenced by either recanalization technique.

The mean thrombus treatment time was significantly (P < .01) shorter for thrombectomy than for thrombolysis. However, the mean procedure times did not differ significantly between the two treatment modalities. Since the time of actual thrombus treatment or the activation of the thrombectomy catheter composed only about one-fourth of the total procedure time, the time saved by performing more efficient thrombus removal did not factor in as a substantial time saver. This hydrodynamic thrombectomy system, however, should provide a more substantial time benefit once the user becomes more facile with the device setup and operation, as well as after simplification of the line hookups of the current prototype device.

When looking at the 30- and 90-day primary patency rates, the two groups are again comparable. It is evident that most of the rethrombosis occurred soon, within 24 hours, after recanalization and that the rate of late thrombosis was lower. Even though some grafts have limited longevity, percutaneous recanalization is the least burdensome and most effective way of maintaining graft patency (2,4,7,23,24).

Aspiration of unclotted blood is of concern with aspiration thrombectomy, although to our knowledge little has been written about it. With careful monitoring of the returned fluid volume, excessive blood loss should be avoided (25). The need for monitoring of the returned volume is emphasized by our results that showed a trend toward higher blood loss in the hydrodynamic thrombectomy group. Hemolysis was reported in several studies (7,26–28) in which both mechanical and hydrodynamic thrombectomy devices were used. Trerotola et al (12) mention the wide variation in baseline values for plasma-free hemoglobin in this patient population and the fact that even pulse-spray thrombolysis may be associated with elevation of plasma-free hemoglobin.

The frequency and severity of complications observed in the two groups were similar and within the 6%–22% range that has been reported in larger series (7,11,12,26). Both pulmonary and peripheral arterial embolizations are undoubtedly a matter of concern. In our study, documented embolization during thrombectomy was 5% (three occurrences) versus 2% (one occurrence) during thrombolysis. The rate of subclinical embolization, however, remains unknown, since no systematic evaluation, such as lung scanning, was performed according to this protocol.

None of the embolic events in the thrombectomy group was directly related to hydrodynamic thrombectomy. In the first of the three patients in the thrombectomy group, arterial embolization was most likely associated with retrograde injection of contrast material. In the second patient, embolization occurred during an attempt to mobilize the arterial plug from the graft with a Fogarty catheter. In the third patient, thrombus was intentionally pushed into the venous outflow. In the one patient in the thrombolysis group who experienced an arterial embolism, balloon-related clot dislodgment during angioplasty of the anastomosis was the likely cause.

The three recorded deaths incidentally occurred all in the thrombectomy group. According to the clinical history, none was procedure related. We had not stratified our patients according to cardiac risk factors or rate of prior infectious complications, which might have shown an excess risk in the thrombectomy patients.

A prototype of the current hydrodynamic thrombectomy system had about a 10% distal embolization rate in animal femoral arterial thrombectomy; however, the fragments were microscopic in size and unlikely to cause clinical symptoms (29). Emboli of a similar size were found during experimental evaluation of another hydrodynamic catheter (27). No distal embolization was found angiographically during an early clinical trial with a prototype of the current hydrodynamic thrombectomy system in patients with acute critical ischemia of the lower limb (8).

Similar to any other recanalization technique, hydrodynamic thrombectomy was not 100% successful. The reason for the inability to remove a sufficient amount of thrombus in these instances was not always clear. Old thrombus may not be liquefied and aspirated. Since none of the grafts was occluded for more than 14 days, one would not expect to encounter old clot. However, older, wall-adherent thrombus could have existed along the wall, particularly at the site of puncture lacerations.

We are confident that with a larger experience base, hydrodynamic thrombectomy with a catheter, such as the one we used, will prove to be a valuable tool for maintaining arteriovenous shunt grafts and fistulas for patients whose lives depend on their function.

In conclusion, the results of this prospective randomized clinical trial have established this hydrodynamic thrombectomy system as a safe and effective technique for recanalization of thrombosed hemodialysis grafts. Results are comparable to those of other thrombectomy techniques.

Author affiliations: Clinical Affairs Department, Boston Scientific, Natick, Mass (M.R.G.); Department of Radiology, Good Samaritan Medical Center, Phoenix, Ariz (A.M.P.); Emory University Hospital, Atlanta, Ga (L.G.M.); Methodist Medical Center, Dallas, Tex (J.B.S.); Rush-Presbyterian-St. Luke’s Hospital, Chicago, Ill (T.A.S.M.); UCLA Medical Center, Los Angeles, Calif (S.C.G.); Scott & White Hospital, Temple, Tex (P.A.N.); Marshfield Clinic, Marshfield, Wis (T.L.S.); and Medical University of South Carolina, Charleston (R.U.).

Financial support and disclosure: This study was supported by a grant from Boston Scientific. M.R.G. is an employee of Boston Scientific, which developed, manufactures, and distributes the Oasis Thrombectomy System.


   FOOTNOTES
 
2 Current address: Department of Radiology, New York Medical College, Valhalla, NY Back

Author contributions: Guarantor of integrity of entire study, K.H.B.; study concepts and design, K.H.B., M.R.G.; definition of intellectual content, K.H.B.; literature research, all authors; clinical studies, all authors; data acquisition, all authors; data analysis, M.R.G., K.H.B.; statistical analysis, M.R.G.; manuscript preparation, K.H.B.; manuscript editing and review, all authors.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 

  1. Gaylord G, Taber T. Long-term hemodialysis access salvage: problems and challenges for nephrologists and interventional radiologists. J Vasc Interv Radiol 1993; 4:103-107.[Medline]
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  8. Höpfner W, Bohndorf K, Loeprecht H. A shredding-thrombectomy catheter treats acute critical lower limb ischemia (abstr). J Vasc Interv Radiol 1997; 8:226.[Medline]
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  10. Trerotola SO, Harris VJ, Snidow JJ, Johnson MS. Percutaneous use of the Fogarty adherent clot catheter. J Vasc Interv Radiol 1995; 578-580.
  11. Overbosch EH, Pattynama PMT, Aorts HJM, Kool LJS, Hermans J, Reekers JA. Occluded hemodialysis shunts: Dutch multicenter experience with the Hydrolyser catheter. Radiology 1996; 201:485-488.[Abstract/Free Full Text]
  12. Trerotola SO, Vesely TN, Lund GB, Soulen MC, Ehrman KO, Cardella JF. Treatment of thrombosed hemodialysis access grafts: Arrow-Trerotola percutaneous thrombolytic device versus pulse-spray thrombolysis. Radiology 1998; 206:403-414.[Abstract/Free Full Text]
  13. Rousseau H, Sapoval M, Ballini P, et al. Percutaneous recanalization of acutely thrombosed vessels by hydraulic thrombectomy. Eur Radiol 1997; 7:935-941.[Medline]
  14. Vorwerk D, Schurmann K, Mueller-Leise C, et al. Hydrodynamic thrombectomy of haemodialysis grafts and fistulae: results of 51 procedures. Nephrol Dial Transplant 1995; 6:1058-1064.
  15. Van Ommen VG, van der Veen FH, Geskes GG, et al. Comparison of arterial wall reaction after passage of the Hydrolyser device versus a thrombectomy balloon in an animal model. J Vasc Interv Radiol 1996; 7:451-454.[Medline]
  16. Soulen MC, Zaetta JM, Amygdalos MA, Baum RA, Haskal ZJ, Schlansky-Goldberg RD. Mechanical declotting of thrombosed dialysis grafts. J Vasc Interv Radiol 1997; 8:563-567.[Medline]
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