Pulsed-spray pharmacomechanical thrombolysis: preliminary clinical results

Better late than never: initial experience of intra-arterial pulsed-urokinase-injection as a salvage therapy for refractory sudden sensorineural hearing loss

BACKGROUND AND PURPOSE

Cochlear vascular micro-thrombosis has been hypothesized as one of the pathogenic mechanisms for sudden sensorineural hearing loss (SSNHL) refractory to regular management. This study aimed to evaluate the feasibility and safety of intra-arterial pulsed-injection urokinase (IAPU) as a salvage therapy for SSNHL after the failure of conventional therapy.

METHODS

We retrospectively reviewed our patient database to identify refractory SSNHL patients between November 2017 and July 2020. Study outcomes before and after the IAPU therapy were compared between IAPU and conventional therapy groups.

RESULTS

Sixty-seven moderate-profound SSNHL patients (29 in IAUP group, 38 in control group) were included in this study. Compared to the control group, patients in the IAPU group showed more significant improvement in pure tone average (PTA) (34.2 ± 23.5 vs. 10.7 ± 13.1, p < 0.001) and degree of hearing recovery (total: 20.7% vs. 5.3%, partial: 24.1% vs. 10.5%, mild: 27.6% vs. 13.2% and non: 27.6% vs. 71.1%) 2 weeks after admission. In the IAPU group, a significant improvement of PTA (86.6 ± 11.5 vs. 54.6 ± 20.1 dB, p < 0.005) was observed on the first day after IAPU treatment.

CONCLUSION

In carefully selected SSNHL cases with a highly suspected vascular origin, IAPU is a safe and effective therapy when conventional treatments have failed. Despite the encouraging findings of our work, large studies are needed to better investigate the strengths and limitations of this salvage therapy.

Spontaneous renal artery thrombosis: A rare cause of acute flank pain

Spontaneous renal artery thrombosis is a rare cause of flank pain and can have fatal consequences. We report a case of acute renal artery thrombosis in a 61-year-old man who experienced flank pain and had no medical history. A contrast-enhanced computed tomography scan revealed total thrombotic occlusion of the left renal artery. The patient was taken to interventional radiology, and an urgent catheter-directed thrombolysis of the renal artery was performed. The procedure was successful, with the subsequent arteriogram demonstrating a substantial decrease of the thrombus extent and the recanalization of the left renal artery. This case highlights that emergency renal artery thrombolysis is an effective and safe treatment for acute occlusion of the renal artery.

Ultrasound-Guided Pharmacomechanical Thrombolysis and Angioplasty for Treatment of Acute Thrombotic Prosthetic Arteriovenous Access: 5-Year Experience with 154 Procedures in a Single Center

Pharmacomechanical thrombolysis (PMT) and percutaneous transluminal angioplasty (PTA) for the treatment of acute thrombotic prosthetic arteriovenous access (PAVA) are conventionally guided by radiography, which may cause radiation injury and requires the use of radiographic contrast media. The aim of the present study was to summarize our experience with ultrasound-guided PMT and PTA as an alternative to radiographic guidance. Between December 2012 and October 2016, 114 patients with acute thrombosis of PAVA were treated urgently with ultrasound-guided PMT and PTA to restore blood flow. The patients were followed up every 3 mo postoperatively. The 114 included patients underwent 154 episodes of ultrasound-guided PMT and PTA and were followed up for a mean of 20.7 ± 9.1 mo. The technical success rate was 91.6%, and the clinical success rate was 97.4%. Post-intervention-assisted primary patency rates at 3, 6, 12 and 24 mo were 90.8%, 78.8%, 66.3% and 50.9%, respectively. Post-intervention secondary patency rates at 3, 6, 12 and 24 months were 96.3%, 94.5%, 90.6% and 85.4%, respectively. PMT and PTA for the treatment of PAVA were performed successfully under the guidance of ultrasound with a success rate similar to that under radiographic guidance, thus avoiding radiation injury and contrast medium use, although close surveillance and timely intervention are imperative to ensure long-term patency.

Inertial Cavitation Ultrasound with Microbubbles Improves Reperfusion Efficacy When Combined with Tissue Plasminogen Activator in an In Vitro Model of Microvascular Obstruction

We have previously reported that long-tone-burst, high-mechanical-index ultrasound (US) and microbubble (MB) therapy can restore perfusion in both in vitro and in vivo models of microvascular obstruction (MVO). Addition of MBs to US has been found to potentiate the efficacy of thrombolytics on large venous thrombi; however, the optimal US parameters for achieving microvascular reperfusion of MVO caused by microthrombi, when combined with tissue plasminogen activator (tPA), are unknown. We sought to elucidate the specific effects of US, with and without tPA, for effective reperfusion of MVO in an in vitro model using both venous and arterial microthrombi. Venous- and arterial-type microthrombi were infused onto a mesh with 40-μm pores to simulate MVO. Pulsed US (1 MHz) was delivered with inertial cavitation (IC) (1.0 MPa, 1000 cycles, 0.33 Hz) and stable cavitation (SC) US (0.23 MPa, 20% duty cycle, 0.33 Hz) regimes while MB suspension (2 × 106 MBs/mL) was infused. The efficacy of sonoreperfusion with these parameters was tested with and without tPA. Sonoreperfusion efficacy was significantly greater for IC + tPA compared with tPA alone, IC, SC and SC + tPA, suggesting lytic synergism between tPA and US for both venous- and arterial-type microthrombi. In contrast to our previous in vitro studies using 1.5 MPa at 5000 US cycles without tPA, the IC regime employed herein used 90% less US energy. These findings suggest an IC regime can be used with tPA synergistically to achieve a high degree of fibrinolysis for both thrombus types.

Interventional Management of Venous Thromboembolism: State of the Art

OBJECTIVE

The purpose of this article is to describe the indications for and approach to catheter-based treatment of acute venous thromboembolism (VTE).

CONCLUSION

Catheter-based treatment of VTE is a viable adjunct to anticoagulant therapy and is being rapidly adopted around the United States. Early data suggest that these therapies reduce postthrombotic sequelae and improve quality of life, but bleeding events are still frequent, particularly at low-volume centers. Protocols need to be standardized to improve patient care.

The Hydrolyser Thrombectomy Catheter: A Single-Center Experience

Purpose:

To present a single-center experience with a mechanical hydrodynamic thrombectomy system (Hydrolyser) in native arteries, veins, and bypass grafts.

Methods:

The Hydrolyser is a 7F, double lumen, over-the-wire thrombectomy catheter. The device was used in 41 patients (22 males; mean age 68 years, range 40 to 90), with recent thromboses (aged 1 to 30 days, mean 8.7 ± 8.5), measuring from 4 to 35 cm long (mean 17.7 ± 9.5). The occlusions were located in native lower limb arteries (n = 28), bypass grafts (n = 8), superior venae cavae (n = 2), axillary vein (n = 1), and pulmonary arteries (n = 2).

Results:

Immediate technical success (residual clot < 50% of lumen diameter) was achieved in 34 patients (83%): 22/28 native arteries (78%), 7/8 bypass grafts (87%), and all pulmonary arteries, superior venae cavae, and the axillary vein. The 7 failed patients were treated surgically (bypass graft or Fogarty balloon). Adjunctive procedures were used to maximize luminal diameter: angioplasty (n = 29, with 13 immediate stent implantations), thromboaspiration (n = 17), and thrombolysis (n = 10). One case of distal embolism was the only complication (treated by thromboaspiration). At 30 days, 30 (73%) vessels remained patent.

Conclusions:

The Hydrolyser system is a promising concept for percutaneous thrombectomy. It is a quick, reliable, efficient device that may offer an alternative to thrombolysis and surgical thrombectomy.

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.

Efficacy of a modified pharmacomechanical thrombolysis technique for endovascular treatment of thrombosed prosthetic arteriovenous grafts

Objective

We applied a modified pharmacomechanical thrombolysis (PMT) technique to endovascular treatment of thrombosed arteriovenous (AV) grafts without the use of any mechanical thrombectomy devices. The aim of this study was to evaluate the efficacy of the PMT technique in the treatment of thrombosed AV grafts by analyzing the long-term patency.

Materials and Methods

Eighty-two patients with thrombosed AV grafts were treated with the PMT technique. AV graft surveillance to detect failing/failed access was followed by endovascular treatment.

Results

The technical and clinical success rates were 95% and 95%, respectively. The total number of thrombolysis sessions was 279. A post-intervention primary patency rate was 45% and 22% at 12 and 24 months, respectively. The secondary patency rate was 96% and 91% at 12 and 24 months, respectively. No major complications were noticed.

Conclusion

The modified PMT technique is effective in endovascular treatment of thrombosed AV grafts.

Percutaneous options for acute deep vein thrombosis

Anticoagulant therapy is associated with poor late limb outcomes in many patients with deep vein thrombosis (DVT). Because systemic thrombolysis and surgical thrombectomy have inherent limitations, image-guided percutaneous thrombus removal is currently favored. Pharmacologic thrombolysis is effective in removing thrombus, but long-term benefit has not been conclusively demonstrated and major bleeding rates appear to be higher than those observed with anticoagulation alone. Percutaneous mechanical thrombectomy is limited as a stand-alone DVT treatment method by inability to clear large thrombosed veins completely and by pulmonary embolism. Pharmacomechanical thrombolysis represents the most promising currently available method to treat DVT. Randomized trials with long-term follow-up are needed to determine the appropriate indications for these procedures. In the meantime, a highly individualized approach to selection of patients is recommended, taking into account the chronicity and anatomic extent of DVT, the presence of circulatory compromise, the patient's bleeding risk profile, life expectancy, and anticipated activity level.

Phase 1 study of human plasma-derived plasmin (TAL-05-00018) in hemodialysis graft occlusion

INTRODUCTION

Hemodialysis grafts often fail because of stenosis at the venous anastomosis resulting in thrombosis. Percutaneous intervention involves thrombolysis with plasminogen activators, mechanical removal of thrombus, and angioplasty of the stenotic lesions.

OBJECTIVES

This article describes a phase I trial using plasmin (human) TAL 05-00018, a direct-acting fibrinolytic agent, to evaluate safety and, secondarily, to establish effective thrombolytic dosing.

PATIENTS/METHODS

Six cohorts of five patients with acute HD graft occlusion documented by fistulagrams were treated with increasing dosages of plasmin (1, 2, 4, 8, 12, and 24 mg) infused within the graft over 30 min via two criss-crossed pulse-spray catheters. The primary efficacy endpoint was at least 50% thrombolysis, as determined by fistulography.

RESULTS

There was no significant change in plasma alpha-2 antiplasmin or fibrinogen concentration, major bleeding did not occur, and there were no deaths. Serious adverse events in four patients were not related to the study drug. There was a dose-response relationship for the primary efficacy endpoint, all five subjects receiving 24 mg achieving more than 75% lysis.

CONCLUSION

This first phase I study of plasmin (human) TAL 05-00018, infused into thrombosed HD grafts, documents safety at all doses and an effective thrombolytic dosage of 24 mg indicating that further investigation into locally delivered plasmin is warranted.

Acute pulmonary thromboembolism after distal gastrectomy: an appraisal of the guidelines for preventing pulmonary thromboembolism/deep vein thrombosis

We report a case of acute pulmonary thromboembolism after gastrectomy. A 67-year-old woman was found to have gastric cancer and a giant lipoma in the ascending colon. We performed distal gastrectomy and enucleation of the ascending colon lipoma. On postoperative day 9, an acute pulmonary thromboembolism developed, and thrombolytic therapy was urgently performed. The 2004 Japanese guidelines for preventing pulmonary thromboembolism/deep vein thrombosis are discussed in relation to the present case.

A first-in-human phase I trial of locally delivered human plasmin for hemodialysis graft occlusion

BACKGROUND

Hemodialysis (HD) grafts often fail because of stenosis at the venous anastomosis and thrombotic occlusion. Percutaneous management relies on thrombolysis with plasminogen activators, mechanical removal of thrombus, and angioplasty of the stenotic lesion.

OBJECTIVES

This report describes a phase I trial using Plasmin (Human) TAL 05-00018, a direct-acting fibrinolytic agent, to evaluate safety and, secondarily, to establish effective thrombolytic dosing.

PATIENTS/METHODS

Six cohorts of five patients with acute HD graft occlusion documented by angiography were treated with escalating dosages of plasmin (1, 2, 4, 8, 12, and 24 mg) infused over 30 min via criss-crossed pulse-spray catheters within the graft. The primary efficacy endpoint was > or =50% thrombolysis, as determined by comparison of pre-plasmin and 30-min post-plasmin fistulograms.

RESULTS

Of 31 subjects who received study drug (safety population), one withdrew and 30 completed the trial (evaluable for efficacy). There was no significant change in plasma alpha-2 antiplasmin or fibrinogen concentration, major bleeding did not occur, and there were no deaths. Serious adverse events in four patients were not related to the study drug. There was a dose-response relationship for the primary efficacy endpoint, all five subjects receiving 24 mg achieving >75% lysis.

CONCLUSIONS

This first phase I study of Plasmin (Human) TAL 05-00018, infused into thrombosed HD grafts, documents safety at dosages of 1-24 mg and an effective thrombolytic dosage of 24 mg. The results establish a foundation for further clinical study of catheter-based plasmin administration in thrombotic disorders.

Development of a novel catheter preventing the outflow of debris and thrombus on percutaneous transluminal angioplasty for hemodialysis access fistulas

If a large amount of debris or thrombus dislodges from a lesion because of dilation of the stenotic or occluded lesion in the hemodialysis access fistula when angioplasty is performed, it may move into the pulmonary artery via the central vein, resulting in pulmonary embolism. A novel sheath has been developed to prevent the outflow of debris or thrombus to the central vein. The catheter consists of a 5 F sheath introducer and a silicone balloon attached at the tip of the sheath. The silicon balloon is inflated via small inflation lumen on the shaft wall of the sheath. In the case of percutaneous transluminal angioplasty (PTA), the silicone balloon is inflated to block the blood flow by a mixture of contrast medium and physiological saline, and then dilate a stenotic or occluded lesion by PTA balloon. Next, the debris and thrombus are aspirated using the flush-lumen of this device. Finally, the silicone balloon is deflated and the dilation of the lesion is confirmed. A case of hemodialysis access fistula graft with massive thrombotic occlusion was presented. This device enabled Fogarty procedure using PTA balloon and the blood flow of the graft was completely improved and a large amount of thrombus was removed. This novel device is useful to prevent the embolic complication of the intervention for hemodialysis access fistula.

Pulse-spray Pharmacomechanical Thrombolysis for Proximal Deep Vein Thrombosis

OBJECTIVE

The 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.

METHODS

We 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.

RESULTS

The 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.

CONCLUSION

The 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.

Characterization of alteplase (tPA) following delivery through the AngioJet rheolytic catheter

PURPOSE

To analyze alteplase solutions following delivery through the AngioJet Xpeedior rheolytic thrombectomy device to characterize the viability of proteins exposed to high shear stress.

METHODS

Alteplase solutions were prepared by reconstitution in sterile water to obtain a targeted concentration of 1.0 mg/mL. A baseline control sample was obtained. The AngioJet system was modified by occluding the return line to allow collection of the dispersed fluid volume. Alteplase solutions (n=5) were delivered through the 6-F, 120-cm Xpeedior catheter and collected. All samples were assayed and compared to baseline using qualitative visual inspection, ultraviolet spectrophotometry, size exclusion chromatography, and in vitro clot lysis assays.

RESULTS

Analysis of the test solutions demonstrated a mean protein recovery of 98.0%+/-3.5% of targeted concentration; the collected protein was fully active, as determined by clot lysis assays (specific activity > or =100%). All samples were clear and colorless. No significant fragmentation or aggregation of protein was observed.

CONCLUSIONS

Alteplase solutions, when delivered through the AngioJet Xpeedior rheolytic thrombectomy device, remain stable and biologically active in vitro. Further clinical investigation is warranted using this method as a novel approach for pharmacomechanical thrombolysis.

Management of thrombosed dialysis access: thrombectomy versus thrombolysis

More than 250,000 patients per year with end stage renal disease are maintained on long-term hemodialysis. Because of this large population, hemodialysis access procedures now account for a large percentage of operative interventions in the United States. Prosthetic arteriovenous access thrombosis is a frequent complication that occurs at a rate of 0.5 to 0.8 episodes per year and is a major source of hospital admissions, increasing hospital costs, patient morbidity, and physician frustration. Thrombosed grafts often require rescue procedures to extend the life of the graft and make the most use of the limited available access sites. Such salvage procedures of thrombosed prosthetic dialysis shunts may be performed with either conventional surgical or endovascular techniques. Many techniques for declotting have been used, including open surgical thrombectomy, percutaneous pharmacologic or mechanical thrombectomy, and pharmacomechanical techniques. Despite the various treatment options, no individual declotting modality has proven itself superior. Long-term patencies after a single revascularization procedure are meager, with a median of less than 90 days. This article will review prosthetic hemodialysis access graft declotting mechanisms and supporting literature.

Percutaneous management of thrombosed dialysis access grafts

This article reviews current concepts in the percutaneous management of thrombosed polytetrafluoroethylene (PTFE) dialysis access grafts. The maintenance of dialysis access grafts remains a challenging task. Graft surveillance is critical in the prevention of graft thrombosis to prolong graft survival. Once a graft is thrombosed, surgical and percutaneous options are available for restoration of flow. There has been an evolution in the percutaneous treatment of thrombosed dialysis access grafts during the last 20 years, with refinement of pharmacomechanical techniques, allowing for safe and efficacious restoration of flow in thrombosed grafts. There has been emergence of alternative thrombolytic agents to urokinase, which was withdrawn from the United States in late 1998 and recently reintroduced. These alternative thrombolytic agents have similar outcomes compared with urokinase, with the additional advantage of being less expensive. In addition, several mechanical devices, which were popular briefly when urokinase was unavailable, are available currently for use within grafts, with similar success, although their prices have limited widespread use.

Comparison of Urokinase, Alteplase, and Reteplase for Catheter-directed Thrombolysis of Deep Venous Thrombosis

PURPOSE

To compare the efficacy, safety, and costs associated with catheter-directed thrombolysis with urokinase (UK) and the recombinant agents alteplase (tissue plasminogen activator [TPA]) and reteplase (recombinant plasminogen activator [RPA]) in the treatment of symptomatic deep vein thrombosis (DVT).

MATERIALS AND METHODS

The authors conducted a retrospective analysis on 74 patients (82 limbs) who underwent treatment for DVT. Thrombosed extremities were treated with either urokinase with therapeutic heparin dosing (UK group; 38 limbs), alteplase with subtherapeutic heparin dosing (TPA group; 32 limbs), or reteplase with subtherapeutic heparin dosing (RPA group; 12 limbs). Infusion times, dosages, drug costs, success rates, and complications were compared among the groups.

RESULTS

Gender, age, disease location, duration of symptoms, and use of additional interventional therapies did not differ statistically among the three cohorts. Median hourly infused doses, total doses, infusion times, drug costs, and success rates per limb were: UK, 11.3 (10(4)) U/hour, 4.361 million U, 40.6 hours, US dollars 6577, 97.4%; TPA, 0.57 mg/hour, 21.6 mg, 30.8 hours, US dollars 488, 96.9%; RPA, 0.74 U/hour, 21.4 U, 24.3 hours, US dollars 1787, 100.0%. Major and overall complication rates were: UK, 5.3% and 10.5%; TPA, 3.1% and 12.5%; RPA, 8.3% and 16.7%. Infusion times, success rates, and complications were not statistically different among the three groups. Alteplase and reteplase were significantly less expensive than urokinase (P <.001 and P <.01, respectively).

CONCLUSION

Catheter-directed thrombolysis for the treatment of DVT is safe and effective, regardless of the agent used. However, the new recombinant agents are significantly less expensive than urokinase.

Catheter-directed Thrombolytic Therapy for Limb Ischemia: Current Status and Controversies

Absence of urokinase from the United States market for the past 4 years has resulted in increasing experience with other plasminogen activators in catheter-directed thrombolytic therapy. The differences in the pharmacologic properties and biologic behavior of these agents may translate into clinical outcomes that are distinct. Some of these manifestations can be predicted based on the existing large clinical trials in the acute myocardial infarction literature. However, because of the fundamental differences in techniques and thrombolytic regimens, extrapolation of the coronary data may not always predict the performance of these agents in peripheral catheter-directed fibrinolysis. In this article, the current status of the available lytic agents in the treatment of limb ischemia is reviewed.

Catheter-directed Thrombolytic Therapy for Limb Ischemia: Current Status and Controversies

Absence of urokinase from the United States market for the past 4 years has resulted in increasing experience with other plasminogen activators in catheter-directed thrombolytic therapy. The differences in the pharmacologic properties and biologic behavior of these agents may translate into clinical outcomes that are distinct. Some of these manifestations can be predicted based on the existing large clinical trials in the acute myocardial infarction literature. However, because of the fundamental differences in techniques and thrombolytic regimens, extrapolation of the coronary data may not always predict the performance of these agents in peripheral catheter-directed fibrinolysis. In this article, the current status of the available lytic agents in the treatment of limb ischemia is reviewed.

Endovascular recanalization of the thrombosed filter-bearing inferior vena cava

PURPOSE

To evaluate the authors' preliminary experience with use of endovascular methods to treat inferior vena cava (IVC) thrombosis in patients with IVC filters.

MATERIALS AND METHODS

Catheter-directed thrombolysis, balloon maceration, mechanical thrombectomy, and stent placement were used to treat 10 patients with thrombosis of filter-bearing IVCs causing symptoms in 18 limbs. Procedural challenges, technical and clinical success, complications, postprocedural filter status, and postprocedural pulmonary embolism (PE) prophylaxis were monitored.

RESULTS

Technical and clinical success were achieved in 15 of 18 (83%) and 14 of 18 symptomatic limbs (78%), respectively. Major bleeding (muscular hematoma) occurred in one patient (10%). Postprocedural PE prophylaxis included anticoagulation (n = 8) and placement of a new filter into a newly placed Wallstent (n = 1). During clinical follow-up, no clinically detectable PE was observed. Data pertaining to late limb status were available at a median of 19 months (range 1-46 months) follow-up in seven patients: three patients were asymptomatic, two patients had ambulatory edema only, one patient had constant mild edema, and one patient had constant severe edema. Postprocedural filter stability was radiographically documented at a median of 255 days (range, 4-1021 d) of follow-up.

CONCLUSION

Endovascular recanalization of the occluded IVC is feasible even in the presence of an IVC filter.

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

OBJECTIVE

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.

CONCLUSION

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.

Pulse-spray thrombolysis in acute myocardial infarction caused by thrombotic occlusion of an ectatic coronary artery

Pulse-spray thrombolysis was performed in 2 patients with acute myocardial infarction (AMI) caused by thrombotic occlusion of coronary artery ectasia. Case 1, a 66-year-old woman with an inferior AMI underwent emergency coronary arteriography, which revealed occlusion of an ectatic right coronary artery. Primary balloon angioplasty failed to reestablish distal flow. Urokinase was administered through the pulse-spray infusion catheter (UltraFuse) and intravenous recombinant tissue plasminogen activator was also administered. Angiographic disappearance of the thrombus was observed within 30 min of starting the infusion, and there was only mild irregularity in the ectatic coronary artery. Case 2, a 45-year-old man with an inferior AMI underwent emergency coronary arteriography, which revealed occlusion of an ectatic right coronary artery. TIMI-3 flow was soon obtained after administration of 480,000 units of urokinase through the pulse-spray infusion catheter. There was diffuse right coronary ectasia without angiographic evidence of coronary stenosis. Coronary ectasia sometimes develops into AMI without the coexistence of coronary stenosis. Because a massive thrombus plays a major role, pulse-spray thrombolysis is a possible treatment in coronary artery ectasia with thrombotic occlusion.

Contemporary treatment of thrombosed hemodialysis grafts

Maintaining hemodialysis grafts remains a difficult problem. Before the early 1990s, graft declotting was usually performed in the surgical suite. Percutaneous declotting has been evolving since the mid-1980s. Initially, a low-dose thrombolytic infusion of streptokinase through a single catheter was used. Crossing catheters with a higher-dose infusion of urokinase was then introduced. This technique was modified with the adjunctive use of pharmacomechanical techniques with the use of compliant balloons and the adjunctive use of heparin. The advent of the "lyse-and-wait" technique provided a simpler and quicker way to declot thrombosed grafts by using urokinase, with similar outcomes. Since the removal of urokinase from the market, multiple mechanical devices have been used with similar success. Recent reports concerning the use of newer-generation thrombolytic agents report similar outcomes, with a reduction in total cost.

Pulse infusion thrombolysis (PIT) for large intracoronary thrombus: preventive effect against the 'no flow' phenomenon in revascularization therapy for acute myocardial infarction

Because large thrombus is a limitation for revascularization in acute myocardial infarction (AMI), the present study evaluated the effectiveness of pulse infusion thrombolysis (PIT) in patients with an AMI with a large (>15 mm) coronary thrombus, focusing on the occurrence of the 'no flow' phenomenon. The retrospective study compared patients treated before (1988-95; Group A, n=74) and after (1996-99; Group B, n=40) the use of PIT, using the following parameters: lesion success (<50% stenosis during 30-min observation), procedural success (lesion success plus TIMI grade 3 flow), procedural no flow (TIMI grade 0 flow during the procedure with 'back and forth movement' of contrast dye after lesion success), persistent no flow (consistent no flow without any flow improvement at the final visualization despite intensive treatment), reocclusion rate and in-hospital death. Group B was significantly better than Group A in procedural success (90% vs 66%; p=0.005), procedural 'no flow' (51% vs 15%; p<0.001), and persistent 'no flow' (34% vs 10%; p<0.05). Subgroup comparison was performed among the following groups: Direct-BA group (n=44): treated with mechanical angioplasty alone; ICT-BA group (n=40): treated with prior intracoronary thrombolysis and angioplasty; and PIT-BA group (n=30): treated with PIT and angioplasty. There were no differences in thrombus length and lesion success among these 3 groups. Procedural success was best achieved in PIT-BA: 97% vs 52% for Direct-BA (p=0.003) and 68% for ICT-BA (p=0.009). Procedural 'no flow' was least in PIT-BA: 50% vs 3.3% for Direct-BA (p=0.003) and 25% vs 3.3% for ICT-BA (p=0.042). Persistent 'no flow' was less frequent in PIT-BA than Direct-BA: 32% vs 3.3% (p=0.009). However, the difference between ICT-BA and Direct-BA was insignificant: 13% vs 3.3% (p=0.53). There were no differences in reocclusion rate and in-hospital death among the 3 subgroups. And there were no differences between Direct-BA and ICT-BA in any parameters. PIT was effective in preventing 'no flow' in the mechanical revasculalization for AMI especially those cases with a large thrombus.

In vitro function of an adjustable temporary venous spring filter: comparison with the temporary RF02 filter and the permanent Greenfield vena cava filter

RATIONALE AND OBJECTIVES

The authors compared in vitro function of a temporary venous spring filter with that of a temporary RF02 filter and a permanent Greenfield filter.

MATERIALS AND METHODS

All three types of filters were placed in thin polyethylene tubes (diameters, 10.0-18.0 mm). Physiologic saline was substituted for flowing blood, and blood clots of three sizes (6 x 10 mm, 6 x 20 mm, 9 x 20 mm) were funneled to the filters. Clot-trapping ability of each filter and elevation of intraluminal pressure after clot trapping were assessed for each tube size.

RESULTS

No statistically significant elevation in intraluminal pressure was detected immediately after placement of any filter. The clot-trapping ability of the spring filter and of Greenfield filter were slightly lower than that of the RF02 filter, but the differences were not statistically significant. After filters had trapped large clots, a high pressure gradient was detected in the 10.0-mm tube for all filters. The spring filter was associated with a higher pressure than the other filters in the 12.0-mm tube (P < .05).

CONCLUSION

In vitro function of the spring filter was satisfactory in comparison with that of the RF02 filter and the Greenfield filter. For efficient filtering in the inferior vena cava, development of a larger version of the filter may be necessary.

The Hydrolyser thrombectomy catheter: a single-center experience

PURPOSE

To present a single-center experience with a mechanical hydrodynamic thrombectomy system (Hydrolyser) in native arteries, veins, and bypass grafts.

METHODS

The Hydrolyser is a 7F, double lumen, over-the-wire thrombectomy catheter. The device was used in 41 patients (22 males; mean age 68 years, range 40 to 90), with recent thromboses (aged 1 to 30 days, mean 8.7+/-8.5), measuring from 4 to 35 cm long (mean 17.7+/-9.5). The occlusions were located in native lower limb arteries (n = 28), bypass grafts (n = 8), superior venae cavae (n = 2), axillary vein (n = 1), and pulmonary arteries (n = 2).

RESULTS

Immediate technical success (residual clot < 50% of lumen diameter) was achieved in 34 patients (83%): 22/28 native arteries (78%), 7/8 bypass grafts (87%), and all pulmonary arteries, superior venae cavae, and the axillary vein. The 7 failed patients were treated surgically (bypass graft or Fogarty balloon). Adjunctive procedureswere used to maximize luminal diameter: angioplasty (n = 29, with 13 immediate stent implantations), thromboaspiration (n = 17), and thrombolysis (n = 10). One case of distal embolism was the only complication (treated by thromboaspiration). At 30 days, 30 (73%) vessels remained patent.

CONCLUSIONS

The Hydrolyser system is a promising concept for percutaneous thrombectomy. It is a quick, reliable, efficient device that may offer an alternative to thrombolysis and surgical thrombectomy.

Adjustable temporary venous spring filter: in vitro assessment

RATIONALE AND OBJECTIVES

The authors performed an in vitro study to evaluate a temporary venous spring filter that can extend vessels of a wide range of diameters to a slit-shaped canal.

MATERIALS AND METHODS

Filters were placed in thin polyethylene tubes or in porcine inferior vena cava specimens (diameter, 10.0-16.0 mm). Physiologic saline was substituted for blood flow, and blood clots of three sizes (6 x 10, 6 x 20, and 9 x 20 mm) were funneled to the filter. Clot-trapping ability was assessed by the degree of luminal extension.

RESULTS

When the luminal extension was increased from 2.6r to 2.8r (where r is the original radius of the vein models), clot-trapping ability increased significantly (61.1%-87.5% in polyethylene tubes and 15.8%-77.5% in venous specimens, P < .001). When the luminal extension was increased to 3.0r, more than 90% of the clots were trapped in all tubes. After trapping the small, medium, and large clots, mean intraluminal pressure elevation was 1.0, 1.0, and 17.0 cm of saline, respectively.

CONCLUSION

Despite its simple design, the spring filter proved to be an efficient filtering device.

Pattern of dispersion from a pulse-spray catheter for delivery of thrombolytic agents: design, theory, and results

RATIONALE AND OBJECTIVES

The purpose of the study was to qualitatively compare the fluid dispersion characteristics of a commercially available side-slit pulse-spray (PS) catheter with those of a conventional side-hole catheter.

METHODS

The dispersion pattern from a 5-F catheter for PS thrombolysis was evaluated in gelatin models and in human thrombi in vivo and was compared with that from a 5-F side-hole catheter. For in vitro experiments, catheters were placed in gel and pulsed with 0.2 mL of dyed water by hand or continuously infused at a rate of 30 or 60 mL/h with an infusion pump. For clinical studies, a single 0.2-mL pulse of contrast medium was injected before lysis and examined with digital subtraction angiography.

RESULTS

Fluid was distributed evenly from the PS catheter in both gel and thrombi, despite placement of some slits in media with variable viscosity. The side-hole catheter produced a heterogeneous dispersal pattern, and most fluid exited through side holes in areas where outside resistance was lowest.

CONCLUSION

The PS catheter provides more even fluid distribution than the side-hole catheter.

Urokinase does not upregulate the vascular endothelial cell-mediated inflammatory response

PURPOSE

Urokinase is used clinically for thrombolysis, but little is known of its direct effect on vascular endothelial cells. The following experiments were preformed to assess the in vitro effects of urokinase on vascular endothelial cell growth, adhesion molecule expression, and interaction with lymphocytes, polymorphonuclear leukocytes, and platelets.

METHODS

Commercially available human umbilical vein endothelial cells (HUVEC) were cultured with varying concentrations of urokinase (0 to 10,000 IU/ml) (clinical dosage, < or = 500 IU/ml). HUVEC viability was determined from 1 to 4 days. HUVECs were incubated with urokinase (0 to 2000 IU/ml) from 4 to 72 hours. Adherence of 51-chromium-labeled polymorphonuclear leukocytes, platelets, or lymphocytes was then quantitated. In separate experiments HUVEC adhesion molecule expression (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, or endothelial leukocyte adhesion molecule-1) was determined by flow cytometry.

RESULTS

There was a decrease of HUVEC viability at suprapharmacologic urokinase concentrations of > or = 2000 IU/ml compared with nontreated control samples (0 IU/ml, 73% +/- 2%, 2000 IU/ml, 60.5% +/- 1.9%, p < 0.05) presumably because of drug toxicity. There was no significantly increased polymorphonuclear leukocyte, lymphocyte, or platelet adhesion to urokinase-treated HUVEC monolayes at any time point. This was also true for each adhesion molecule tested.

CONCLUSIONS

Urokinase at clinically relevant concentrations (< or = 500 IU/ml) did not affect endothelial cell viability or growth, nor did it upregulate adhesion molecule expression or cellular adhesion associated with the cell vascular inflammatory response. It is therefore implied that the use of urokinase in vivo similarly would not initiate the vascular inflammatory response.

Thrombolytic therapy for treatment of pulmonary embolism in the postoperative period: case report and review of the literature

A patient with morbid obesity and insulin-dependent diabetes was admitted to the surgical intensive care unit, four days status postsurgical repair of an umbilical hernia. A pulmonary embolus (PE) was diagnosed by ventilation/perfusion scan and confirmed by transthoracic echocardiogram. A right ventricular ejection fraction/volumetric/oximetry pulmonary artery catheter revealed a very low ejection fraction and cardiac index. Systemic urokinase therapy was initiated and the patient improved considerably over the ensuing 12 hours. Anesthesiologists must be able to diagnose the signs and symptoms of PE and should be familiar with treatment modalities to reverse right ventricular dysfunction. Review of the literature regarding thrombolytic therapy in the perioperative period indicates potential benefit in select patients.