Pulse-spray Pharmacomechanical Thrombolysis Research Articles

Needle Directed Pulse Spray Pharmacomechanical Thrombolysis for Acute Thrombosis of Dialysis Fistulas – Technique, Efficacy and Short Term Follow UP

Background: The incidence of end stage renal disease is on the rise and most of these patients are undergoing dialysis either through tunnelled/non tunnelled dialysis catheters or through arteriovenous fistulas/grafts. The dialysis grafts and fistulas have limited durability of about 3 years and are more prone for thrombosis and stenosis. Catheter directed interventions are successful in establishing flow in most of the thrombosed fistulas, but require dedicated Cath lab and tertiary care centre. Needle directed thrombolysis is a novel economical, safe technique for thrombolysis of dialysis fistulas and grafts. The aim of the studt is to review the technique, safety, efficacy of needle directed pulse spray pharmacomechanical thrombolysis of dialysis fistulas and grafts with short term follow up. Subjects and Methods: This was a prospective observational study done in department of Radio diagnosis, Narayana medical college, Nellore. Selectively 25 patients with thrombosed AV fistulas were referred from nephrology OPD for needle directed thrombolysis to our department from December 2018 to May 2019. The procedure was performed on OPD basis in ultrasound procedure room. Regular Doppler follow up of patients is done up to 6 months. Results: Out of twenty five cases about seventeen cases (68%) were successful in achieving adequate recanalization in single session. four cases (16%) required repeat sessions of thrombolysis and were successful in second attempt. In four cases (16%) there was failure in attaining adequate recanalization due to marked multisegment attenuation/flow limiting stenosis of the draining vein. Conclusion: Needle directed Pulse spray pharmacomechanical thrombolysis is a novel technique, which can be done bedside, under portable ultrasound guidance and is an economical procedure as no intervention hardware is required. Continuous monitoring allows procedure to be stopped at the earliest once there is optimal recanalization, minimizing the systemic side effects of thrombolytic agents.

A Case of Needle-Directed Pulse-Spray Pharmacomechanical Thrombolysis of Acute Brachial Artery Thrombosis

AbstractAcute limb ischemia is a serious disabling condition. The management options depend upon the patient symptoms and signs of ischemia in the affected limb. The management options include surgical thrombo-embolectomy and catheter directed thrombolysis. Catheter directed thrombolysis has now become the first line of management in symptomatic cases. Here, we discuss a case of acute left brachial artery thrombosis which was successfully managed by needle-directed pulse-spray thrombolysis.

Pulse-Spray Pharmacomechanical Thrombolysis of Native Arteriovenous Fistulas and Grafts under Ultrasound Guidance: Our Initial Experience

AbstractChronic renal diseases have been on rise with most patients requiring renal transplantation. With advances in treatment, patients undergo hemodialysis through arteriovenous (AV) fistulas and grafts. Thrombosis in these fistulas and grafts are more common and may result in failure. Interventional radiology plays an important role in managing these thromboses through catheter-directed thrombolysis. With success rate of more than 80%, catheter-directed thrombolysis has become the treatment of choice. However, the need of trained personnel, well-equipped catheter laboratories, and expensiveness are its disadvantages. We share our initial experience in two patients in whom we have performed ultrasound-guided percutaneous pulse-spray pharmacomechanical thrombolysis as a day-care procedure. This technique is less expensive, can have a wider outreach, and patients can be benefitted early to avoid new access.

USG-guided needle-directed pulse-spray pharmaco-mechanical thrombolysis of hemodialysis grafts/fistula: A novel technique.

The incidence of end-stage renal disease is significantly increasing and most patients who require renal transplantation are undergoing hemodialysis through tunneled/non-tunneled dialysis catheters and arteriovenous fistulas. The greatest disadvantage of the hemodialysis access is the limited durability of the arteriovenous fistulas and grafts, which, on average, remain patent for <3 years, but are the lifeline for hemodialysis patients. Catheter-directed interventions are successful in re-establishing flow in more than 80% of thrombosed hemodialysis fistulas and have become the treatment of choice for failing or thrombosed accesses. However, these interventions are expensive and require a tertiary center with well-equipped labs. The novel technique of needle-directed thrombolysis is less expensive and can be done on an OPD basis in any primary healthcare setup. To the extent we have searched, no such technique has been published so far in the English literature.

Quality Improvement Guidelines for the Treatment of Lower Extremity Deep Vein Thrombosis with Use of Endovascular Thrombus Removal

Suresh Vedantham, MD, Akhilesh K. Sista, MD, Seth J. Klein, MD, Lina Nayak, MD, Mahmood K. Razavi, MD, Sanjeeva P. Kalva, MD, Wael E. Saad, MD, Sean R. Dariushnia, MD, Drew M. Caplin, MD, Christine P. Chao, MD, Suvranu Ganguli, MD, T. Gregory Walker, MD, and Boris Nikolic, MD, MBA, for the Society of Interventional Radiology and Cardiovascular and Interventional Radiological Society of Europe Standards of Practice Committees

Quality Improvement Guidelines for the Treatment of Lower Extremity Deep Vein Thrombosis with Use of Endovascular Thrombus Removal

Quality Improvement Guidelines for the Treatment of Lower Extremity Deep Vein Thrombosis with Use of Endovascular Thrombus Removal

Percutaneous Treatment of Failed Native Dialysis Fistulas: Use of Pulse-Spray Pharmacomechanical Thrombolysis as the Primary Mode of Therapy

ObjectiveTo determine the efficacy and outcome of percutaneous treatment in restoring the function of failed native arteriovenous fistulas (AVFs) where pulse-spray pharmacomechanical thrombolysis was used as the primary mode of therapy.Materials and MethodsFrom June 2001 to July 2005, 14 patients who had thrombosis of native AVFs underwent percutaneous restoration following 20 episodes of thrombosis. These included 6 repeated episodes in one forearm AVF and two episodes in another forearm AVF. All patients except one were treated with urokinase injection utilizing the pulse-spray technique and had subsequent balloon angioplasty. One patient was treated by percutaneous angioplasty alone. We retrospectively evaluated the feasibility of percutaneous treatment in restoring the function of the failed AVFs. The primary and secondary patencies were calculated by using a Kaplan-Meier analysis.ResultsBoth technical and clinical success were achieved in 15 (75%) of 20 AVFs. Four of the five technical failures resulted from a failure to cross the occluded segment. One patient refused further participation in the trial through a brachial artery access following failure to cross the occluded segment via an initial retrograde venous puncture. There were no major precedure related complications observed. Including the initial technical failures, primary patency rates at six and 12 months were 64% and 55%, respectively. Secondary patency rates at six and 12 months were 71% and 63%, respectively.ConclusionPulse-spray pharmacomechanical thrombolysis for treatment of the thrombosed AVFs is safe, effective and durable. This procedure should be considered as an option for the management of failed AVFs prior to surgical intervention.

Pulse-spray Pharmacomechanical Thrombolysis for Proximal Deep Vein Thrombosis

ObjectiveThe aim of this study was to evaluate the efficacy, safety, and feasibility of pulse-spray pharmacomechanical thrombolysis to treat proximal deep vein thrombosis (DVT) in conjunction with the placement of a non-permanent IVC filter. MethodsWe studied 31 consecutive patients with acute proximal DVT defined as the inferior vena cava (IVC), iliac vein and/or femoral vein, who were diagnosed using duplex ultrasonography and/or contrast venography. All were treated with pulse-spray urokinase. Early success was assessed by comparing the pre- and post-treatment venographic severity score. Non-permanent IVC filters were used to reduce the risk of pulmonary thromboembolism. ResultsThe average total urokinase dose was 1.71 million IU (range: 0.72–3.6 million IU) and the average duration of therapy was 2.4 days. The average percentage of thrombus lysed was 85% (range: 22–100%). A large thrombus trapped by the filter was detected using cavography before extraction of the filter in one patient. There was no major treatment-related adverse event. ConclusionThe combination of pulse-spray pharmacomechanical thrombolysis and the prophylactic use of a non-permanent IVC filter was a safe and effective approach for treating acute proximal DVT.

Original report. Pulse-spray thrombolysis of thrombosed hemodialysis grafts with tissue plasminogen activator.

The purpose of this study was to evaluate pulse-spray pharmacomechanical thrombolysis with the use of tissue plasminogen activator in the recanalization of thrombosed hemodialysis access grafts. Pulse-spray pharmacomechanical thrombolysis with tissue plasminogen activator is an effective method for percutaneous recanalization of thrombosed hemodialysis access grafts with results similar to other percutaneous techniques.

Percutaneous Intervention for Permanent Hemodialysis Access

Purpose: To evaluate the effectiveness of percutaneous transluminal angioplasty (PTA) and pulse-spray pharmacomechanical thrombolysis (PSPMT) using urokinase for the management of insufficient hemodyalitic access, and to identify contributory patency-related factors following interventional procedures. Materials and Methods: Between August 1995 and July 2001, 105 cases of insufficient hemodyalitic access involving 38 artificial arteriovenous fistulae (AVF) and 67 graft arteriovenous fistulae (AVG) were treated interventionally. The patients underwent PTA alone in 53 cases and PSPMT combined with PTA in 47, and procedural success and long-term patency were evaluated in terms of a patient's age and sex, the presence of diabetes, the location of access, the type of AVG, the draining vein of AVG, the presence of central vein stenosis, the degree of residual stenosis, and the method of interventional procedure, and contributory factors were thus identified. Results: The overall technical success rate of interventional management was 83.8% (88/105), while the overall primary patency rate was 58.75.2% at 6 months, 43.06.0% at 1 year, and 18.16.0% at 2 years. In AVF/AVG groups, primary patency rates were 55.99.2%/57.86.5% at 6 months, 45.810.0%/42.78.4% at 1 year, and 21.8%9.8%/18.96.5% at 2 years. The overall secondary patency rate was 40.08.1% at 2 years. No contributory factors were found (95% confidence level), though patency of access decreased when residual stenosis was more than 30% (p=0.054). Conclusion: Interventional management of insufficient hemodyalitic access has high success and patency rates, and is an effective primary method. There appear to be no contributory factors, though residual stenosis of more than 30% tends to decrease the patency of hemodialytic access.

Pulmonary Embolism from PulseSpray Pharmacomechanical Thrombolysis of Clotted Hemodialysis Grafts: Urokinase versus Heparinized Saline

To compare the frequency and extent of pulmonary embolism (PE) occurring during pulse-spray pharmacomechanical thrombolysis (PSPMT) of clotted hemodialysis grafts with use of either urokinase (UK) or heparinized saline (HS). Postintervention primary patency and complication rates were compared for each method of thrombolysis. Twenty-seven patients were enrolled in this prospective, randomized, double-blind study evaluating PE with two PSPMT agents. The doses of heparin were similar between groups. The only variable was that one group of patients received UK and the other received HS. In two cases, the venous anastomosis could not be crossed. Eleven patients were treated with UK and 14 with HS. Nuclear medicine perfusion lung scans were performed before treatment and after graft declotting procedures. Lung perfusion was quantified to 10% of a pulmonary segment (0 = normal perfusion, 1 = segmental perfusion defect), with nine segments counted for each lung. Baseline nuclear medicine perfusion lung scan results were abnormal (> or = 20% segmental perfusion defect) in 19 patients (70.4%). New PE (one or more pulmonary segments) occurred in two patients treated with UK (18.2%) and nine patients treated with HS (64.3%; P = .04). All cases of PE were asymptomatic. Quantitative global pulmonary perfusion analyses revealed that treatment with UK improved flow to 0.2 +/- 2.0 pulmonary segments, whereas treatment with HS decreased perfusion to 1.0 +/- 1.7 segments (P = .16, NS). Although postintervention primary patency rates were similar according to life-table analysis (P = .76, NS), complication rates were higher with use of HS (n = 4, 28.6%) than with use of UK (n = 2, 18.2%) (P = .6, NS). All PE were asymptomatic during PSPMT, but treatment with UK reduced the rate of PE and tended to result in smaller defects in lung scan results. Most patients undergoing hemodialysis have abnormal baseline perfusion scan results, but PSPMT with UK improved many of them. The postintervention primary patency rates were similar between groups, but complications were more frequent after treatment with HS.

Alteplase as an Alternative to Urokinase

For the past 20 years, urokinase (UK) has been the primary agent used in the United States for catheter-directed thrombolytic therapy of acute limb ischemia and deep vein thrombosis (DVT), and for restoration of patency in hemodialysis access and clotted intravenous access devices ( 1 Ouriel K Surgery versus thrombolytic therapy in the management of peripheral arterial occlusions. JVIR. 1995; 6: 48S-54S Abstract Full Text PDF Scopus (16) Google Scholar , 2 Semba CP Dake MD Iliofemoral deep venous thrombosis: aggressive therapy with catheter-directed thrombolysis. Radiology. 1994; 191: 487-494 PubMed Google Scholar , 3 Bookstein JJ Fellmeth B Roberts A Valji K Davis G Machado T Pulse-spray pharmacomechanical thrombolysis: preliminary clinical results. Am J Radiol. 1989; 152: 1097-1100 Google Scholar , 4 Haire WD Atkinson JB Stephens LC Kotulak GD Urokinase versus recombinant tissue plasminogen activator in thrombosed central venous catheters: a double-blinded, randomized trial. Thromb Haemost. 1994; 72: 543-547 PubMed Google Scholar ). However, in 1999, the Food and Drug Administration suspended the sales and distribution of UK (Abbokinase; Abbott Laboratories, Abbott Park, IL) in the United States ( 5 Center for Biologics Evaluation and Research, Public Health Service Important Drug Warning: Dear Healthcare Provider. Available online at. http://www.fda.gov/cber/ltr/abb012599.html Google Scholar ). Unfortunately, few American interventionalists had previous experience in the use of alternative agents to UK. To address this urgent clinical crisis, a multidisciplinary Advisory Panel on Catheter-Directed Thrombolytic Therapy consisting of vascular specialists was organized by the Society of Cardiovascular and Interventional Radiology (SCVIR) and convened in New York, NY, on August 9, 1999, to develop preliminary recommendations for the benefit of SCVIR members. The goal of the advisory panel was to: (i) identify alternative plasminogen activators; (ii) review the published literature on alternative plasminogen activators; (iii) review the multidisciplinary advisory panel experience with the use of alternative agents; and (iv) develop preliminary clinical guidelines for managing acute limb ischemia, DVT, thrombosed dialysis grafts, and clotted intravascular catheters and ports. This document is a summary of the Advisory Panel meeting and is intended for the establishment of guidelines in the use of alternative agents to UK in clinical practice. The meeting was supported by an unrestricted educational grant from Genentech, Inc. (South San Francisco, CA) and sponsored by the SCVIR.

Declotting grafts with thrombolysis

Percutaneous declotting of dialysis grafts has been evolving since its introduction in the early 1980s. At first, a low-dose thrombolytic infusion through a single catheter was used. Crossing catheters with a higher dose infusion was then introduced. The next method used was a pharmacomechanical thrombolysis, which uses crossing catheters and pulse-spray technique. Mechanical displacement of the platelet plug at the arterial anastomosis is necessary. Residual clot in the midgraft is mobilized with Fogarty balloons and/or angioplasty balloons. The underlying cause of graft failure, which is typically a stenosis at the venous anastomosis, must be addressed. The viability of a graft after successful lysis is probably most dependent on successful treatment of the lesion that caused the graft to thrombose. If an angioplasty of this lesion is not successful, one can consider directional atherectomy or stents. Alternatively, a surgical repair with a patch angioplasty or with an interposition graft can be performed. Recently, alternative declotting devices have been introduced. The Amplatz device and the Possis device are 2 such devices. Additionally, aspiration thrombectomy is being used with or without addition of lytic agents to attempt to declot grafts. These newer devices and techniques must be shown to be similar in terms of efficacy and cost when compared to pharmacomechanical thrombolysis before being considered for widespread use. Ultimately, it is the management of the platelet plug at the arterial anastomosis and the venous stenosis that will determine how long the graft will function after the procedure. The lyse and wait (L&W) technique was described in 1997 as a quick and simple method to declot arteriovenous (AV) grafts. A 250,000 U urokinase (5 mL), 5,000 U heparin (1 mL) mixture (total 6 mL) is injected into the graft via a 22-gauge angiocatheter. This mixture is allowed to sit in the graft for 30 to 60 minutes. The same technique can be used with any lytic agent. A multicenter randomized prospective study comparing pulse-spray pharmacomechanical thrombolysis versus L&W was recently completed. Eighty-eight patients were randomized. L&W on the average was 20 minutes quicker than pulse-spray with similar technical success and patencies. With similar results and faster procedure times, we believe L&W to be a good alternative for dialysis qraft declotting.

Patency of Wallstents placed across the venous anastomosis of hemodialysis grafts after percutaneous recanalization.

To determine the patency of Wallstents placed across the venous anastomosis of prosthetic bridge grafts after percutaneous graft recanalization. Wallstents were placed across 26 lesions at the venous anastomosis of polytetrafluoroethylene (PTFE) grafts in 25 patients (11 men, 14 women; age range, 29-83 years; mean age, 65.4 years) after pulse-spray pharmacomechanical thrombolysis. Indications for stent deployment included acute angioplasty failure, rapid restenosis, and vessel perforation. The initial success rate was 100%. The mean primary graft patency rates (+/- standard error) at 3 and 6 months were 34% +/- 9 and 27% +/- 9, respectively. Secondary patency rates were 77% +/- 8 at 3 months, 72% +/- 9 at 6 months, and 50% +/- 10 at 12 months. Eight of the 26 grafts continued to be used for hemodialysis at the end of follow-up. After angioplasty failure or vessel perforation, Wallstent placement at the venous anastomosis of recanalized PTFE grafts can salvage hemodialysis access function. The results of this study indicate that the 1-year secondary patency rate of these grafts is 50%, which approaches the reported rates of patency after balloon dilation as part of percutaneous graft recanalization.

Augmented Pulse-Spray Thrombolysis with tPA by Early Pulsed Intrathrombic Plasminogen Enrichment

This study was designed to evaluate the efficacy of plasminogen enrichment of subacute thrombus in further accelerating pulse-spray pharmacomechanical thrombolysis (PSPMT) with urokinase (UK) or tissue plasminogen activator (tPA) in a rabbit model. With use of a subacute rabbit inferior vena cava (IVC) thrombosis model, 78 rabbits were divided into eight groups according to the agents used for thrombolysis: (i) controls (IVC thrombosis, no lysis performed), (ii) pulse-spray thrombolysis with saline only, (iii) PSPMT with UK, (iv) PSPMT with UK, plus interim pulse-spray plasminogen enrichment after 14 minutes, (v) pulse-spray plasminogen enrichment, followed at 10 minutes by PSPMT with UK, (vi) PSPMT with tPA, (vii) PSPMT with tPA, plus interim plasminogen enrichment, and (viii) pulse-spray plasminogen enrichment, followed at 10 minutes by PSPMT with tPA. Intrathrombic pulsed injection of glu-plasminogen after 14 minutes of tPA PSPMT demonstrated significant augmentation of lysis (approximately 31% decrease in residual thrombus) compared with tPA alone (P = .006). Lysis was not augmented significantly when plasminogen was sprayed into thrombus before tPA, or before or after UK. Plasminogen enrichment of thrombus after onset of PSPMT with tPA significantly accelerated thrombolysis in a subacute in vivo rabbit model. A clinical trial of this method may be warranted.

Pulmonary emboli from pulse-spray and mechanical thrombolysis: evaluation with an animal dialysis-graft model.

To compare pulmonary emboli resulting from pulse-spray pharmacomechanical thrombolysis (PSPMT) and mechanical thrombolysis performed to declot dialysis-access grafts. Polytetrafluoroethylene arteriovenous shunts were created in eight dogs and were deliberately clotted at monthly intervals. Animals were randomly assigned to treatment with pulse-spray urokinase thrombolysis or a low-speed rotational percutaneous thrombolytic device. Perfusion imaging, pulmonary-artery pressure measurements, and pulmonary arteriography were performed before and after each procedure. A total of 22 procedures were performed (11 PSPMT and 11 mechanical thrombolysis). Declotting was successful in all procedures, with 100% 30-day patency. Segmental defects were seen on perfusion images after 10 (91%) of 11 PSPMT procedures and two (18%) of 11 mechanical thrombolysis procedures (P < .002). Transient increases in pulmonary-artery pressure occurred in the PSPMT group. Complete resolution of emboli and return to baseline pressures were seen in all cases, even after multiple (up to four) procedures in the same animal. There was no histologic evidence of pulmonary infarction in either group. The percutaneous thrombolytic device is effective for declotting dialysis grafts in dogs and results in statistically significantly fewer pulmonary emboli compared with PSPMT.

Pulse-spray pharmacomechanical thrombolysis of thrombosed hemodialysis access grafts: long-term experience and comparison of original and current techniques.

Pulse-spray pharmacomechanical thrombolysis is an evolving method for the treatment of vascular occlusions in which a highly concentrated fibrinolytic agent is injected as a high-pressure spray directly into thrombus. The purpose of this retrospective study was to analyze our long-term experience with this technique for the treatment of clotted hemodialysis grafts and to compare the efficacy and safety of the original and current methods. Over 6 years, 284 cases of dialysis graft thrombosis were considered suitable for treatment with pulse-spray thrombolysis. The original technique involved the injection of highly concentrated urokinase directly into a clot through two crisscross catheters with multiple side holes. The current technique includes early fragmentation of residual clot with a balloon catheter, intrathrombic injection of heparin, mechanical treatment of a lysis-resistant clot at the arterial anastomosis, and routine administration of aspirin. After thrombolysis, underlying obstructions were treated with balloon angioplasty, atherectomy, or stents. The technical success, immediate clinical success, and frequency of complications for the entire population were analyzed. In addition, the results for 36 cases treated with the original technique were compared with the results for 37 recent cases treated with the current technique. Of 284 cases considered suitable for treatment, thrombolysis was not done in eight cases because the venous anastomosis could not be crossed. Thrombolysis was discontinued in two cases because of extravasation of contrast material. The technical success for all grafts considered for treatment was 96%; 92% of treated grafts remained patent for at least 24 hr. Major complications occurred in 1% of cases, and minor complications occurred in 9% of cases. The clinical efficacies of the original and current techniques were 86% and 92%, respectively. The mean thrombolytic agent infusion time was reduced from 44 +/- 20 min to 23 +/- 13 min (p < .001). The overall procedure time for the recently treated subgroup was 67 +/- 26 min. There was no significant difference in the frequencies of major and minor complications between the treatment subgroups. Pulse-spray pharmacomechanical thrombolysis is a reliable, rapid, and safe method for recanalization of occluded dialysis grafts. The current technique has been proven as safe and effective as the original technique but offers the advantage of a significant reduction in the time required for the infusion of thrombolytic agent.

Use of a Direct Thrombin Inhibitor (Argatroban) during Pulse-Spray Thrombolysis in Experimental Thrombosis

To evaluate the effectiveness of intravenous and intrathrombic injection of the thrombin inhibitor argatroban during pulse-spray pharmacomechanical thrombolysis (PSPMT) in experimental venous thrombosis. Clots were produced in the inferior vena cava in 52 rabbits by placement of steel coils and balloon injury to the vessel wall. Two days later, clots were treated with PSPMT. Several treatment methods were used: intrathrombic saline, intrathrombic tissue plasminogen activator (t-PA), intrathrombic t-PA with intrathrombic and intravenous heparin, intrathrombic t-PA with intravenous argatroban, and intrathrombic t-PA with intrathrombic and intravenous argatroban at two different doses. After treatment, the rabbits were killed and residual clot was weighed. Pretreatment clot weight was estimated and clot lysis was assessed. PSPMT with t-PA and adjunctive intrathrombic heparin resulted in greater lysis than PSPMT with only t-PA (percentage of residual clot, 59% +/- 14 vs 81% +/- 28; P = .02). Addition of intravenous argatroban did not increase lysis, but adjunctive intrathrombic argatroban significantly increased lysis at low doses (37% +/- 16; P = .02) and high doses (34% +/- 6; P = .006) compared with t-PA and intrathrombic heparin. In a rabbit model of venous thrombosis, the use of intrathrombic argatroban during PSPMT with t-PA significantly improved clot lysis.

Recurrent Thrombosis of Polytetrafluoroethylene Dialysis Fistulas after Recent Surgical Thrombectomy: Salvage by Means of Thrombolysis and Angioplasty

To test the hypothesis that thrombolysis followed by angioplasty for salvage of thrombosed polytetrafluoroethylene (PTFE) dialysis fistulas is safe and effective even after recent surgical thrombectomy. Thrombolysis and balloon angioplasty were performed on 12 fistulas in which thrombosis had recurred within 30 days after thrombectomy (n = 10) or thrombectomy/revision (n = 2). All patients underwent pulse-spray pharmacomechanical thrombolysis with urokinase and use of a crossed-catheter technique. A total of 250,000-1,000,000 IU of urokinase and 2,500 IU of heparin were injected throughout the clot in 17-33 minutes. A bolus of 2,500 IU of heparin was simultaneously administered intravenously. Thrombolysis was successful in restoring flow in all grafts, but thrombosis recurred in three grafts before they could be used for dialysis. The clinical success rate was thus 75%. There were no major complications. Mean primary patency after thrombolysis in this small select group of patients was 94 days (median, 68.5 days), comparing favorably with the mean patency of 44 days (median, 23 days) achieved by the prior 23 surgical revisions in the same grafts. Percutaneous fistula salvage appears to be a safe and effective means of treating recurrent thrombosis in PTFE dialysis fistulas when recent surgical thrombectomy has failed.

Pulse-spray pharmacomechanical thrombolysis for treatment of thrombosed dialysis access grafts

The results of pulse-spray pharmacomechanical thrombolysis (PSPMT) of 209 thrombosed hemodialysis grafts were reviewed. In PSPMT, concentrated urokinase is injected forcefully through catheters with multiple tiny sideholes or sideslits. Catheters placed in a crisscross fashion cover the entire clot simultaneously. This therapy was successful in treating patients with thrombosed grafts. Of the 200 grafts with complete therapy, 197 grafts (99%) were patent at the end of the procedure. Mean time for pulsed-spray lysis was 40 minutes. Etiologies for graft thrombosis were anastomotic venous outflow stenosis, stenosis of the venous outflow away from the anastomosis, arterial stenosis, intragraft stenosis, pseudoaneurysms, and no identifiable cause in a small percentage. There were 16 complications, 8 of which required additional therapy or potentially compromised the graft. These results suggest that pharmacomechanical thrombolysis and angioplasty provide rapid, consistent, and safe recanalization of thrombosed hemodialysis grafts and represent an additional therapeutic approach to graft management.