Comparison of alteplase and urokinase for pharmacomechanical thrombolysis of clotted hemodialysis access

Rotational thrombectomy versus balloon maceration in dialysis access salvage

BACKGROUND

Although end stage renal disease patients who undergo hemodialysis frequently experience dialysis-associated thrombotic complications, there remains a paucity of literature comparing the efficacy of different endovascular salvage techniques for grafts and fistulas. This study aims to compare primary patency in dialysis access following salvage mechanical thrombolysis/thrombectomy with a rotational thrombolysis device versus balloon maceration.

METHODS

Using a database of patient records at a tertiary medical center, all patients who underwent rotational thrombectomy with the Cleaner XT™ Rotational Thrombectomy System for endovascular salvage of arteriovenous fistula or arteriovenous graft from August 2016 to July 2022 were included in the population. Fourteen patients who underwent balloon maceration for endovascular salvage were matched to the patients in the rotational thrombectomy group based on date of procedure. The primary patency of the fistula or graft for the two groups was measured.

RESULTS

A total of 13 patients who underwent dialysis access salvage with rotational thrombectomy (10 grafts, 3 fistulas) were matched with 14 patients who underwent balloon maceration for dialysis access salvage (10 grafts, 4 fistulas). Six patients in both groups required additional graft access salvage (46% rotational thrombectomy; 43% balloon maceration). The median time to next dialysis salvage was 51 days for rotational thrombectomy and 43.5 days for balloon maceration (W + 9, critical value 1; compatible with statistically significant difference).

CONCLUSION

Endovascular access salvage by rotational thrombectomy may provide longer primary patency compared to salvage by balloon maceration. However, a longer follow-up prospective study of a larger study population is necessary to clarify the safety and efficacy of rotational thrombectomy using the Cleaner XT™ device.

Efficacy and safety of low dose, weight-based subcutaneous enoxaparin protocol in recurrent arteriovenous access thrombosis

BACKGROUND

This study aims to evaluate the safety and efficacy of a short-term, low dose, weight-based subcutaneous enoxaparin protocol (SEP) in maintaining the patency of arteriovenous (AV) access with recurrent thrombosis.

METHODS

Prospective follow-up of 25 patients who presented to a tertiary institution with recurrent AV access thrombosis and treated with anticoagulation according to SEP following successful thrombectomy. Patency and safety outcomes of SEP were studied.

RESULTS

The participants were 66.4 ± 10.2 years old and predominantly male (60%) and of Chinese ethnicity (72%). The AV accesses had a median age of 1.4 (0.6, 5.6) years with 60% being non-autogenous arteriovenous access while 40% were autogenous arteriovenous access. Thrombolytic agents (urokinase (72%) or alteplase (28%)) were used in all procedures while adjunct thrombectomy device was used in only four procedures. The mean dose of enoxaparin was 36.0 ± 8.2 mg or 0.64 ± 0.1 mg/kg/day for a mean duration 30.0 days (Interquartile range: 27.5, 31.0). One patient developed minor bleeding episode. Kaplan-Meier analysis demonstrated that the mean thrombosis-free survival pre- versus post-SEP adoption was 27.3 (95% CI 17.9-36.7) versus 183.5 (95% CI 100.1-266.9) days (p < 0.001). After adjusting for the type of thrombolytic agent, use of adjunct thrombectomy device, cutting balloon, drug-coated balloon, and stent graft, SEP remained a significant factor associated with longer thrombosis-free patency (HR 0.166: 95% CI 0.070-0.392, p < 0.001).

DISCUSSION

SEP appears to be a feasible and safe thromboprophylaxis method to improve thrombosis-free patency for AV access with recurrent thrombosis.

[Acute interventions-dialysis shunt recanalization]

BACKGROUND

An arteriovenous fistula is vital for patients who need regular hemodialysis. Continuous patency and sufficient functionality determine quality of life and associated morbidity and mortality of patients.

PROBLEM

Following successful hemodialysis shunt creation, intimal hyperplasia and consecutive thrombosis or complete occlusion may cause different types of shunt dysfunctionality or even critical failure.

OBJECTIVE

Immediate shunt recanalization and revision by using an endovascular-first approach is crucial for long-term survival of hemodialysis fistula. There are several mechanisms available for catheter-based thrombus removal to unmask the typically underlying shunt stenosis.

METHODS

Primary technical recanalization success rates are very similar for clot cleaning. Treatment of intimal hyperplasia is preferably addressed by using drug-coated balloon angioplasty to allow for increased shunt patency compared to plain old balloon angioplasty. Stents and stent grafts are only used for resistant or repeated short-term recurrence of severe stenosis. Finally, surgical revision has a classical role in case of repeated failure of endovascular measures.

Covid19 vaccination-associated portal vein thrombosis-An interdisciplinary clinical challenge

Despite one of the largest vaccination campaigns in human history, the COVID-19 pandemic has not been yet defeated. More than 10 billion doses of COVID-19 vaccine have been administered worldwide. AstraZeneca's Vaxzevria (ChAdOx1 nCoV-19 / AZD1222) was approved as the first viral vector-based vaccine in the EU on 29 January 2021. Thromboembolic events are a rare complication of vaccination with ChAdOx1 nCoV-19 in the context of, now known as vaccine-induced immune thrombotic thrombocytopenia (VITT), with an incidence of 1.5-3 in 100,000 vaccinations. VITT is clinically as well as pathophysiologically comparable to heparin-induced thrombocytopenia. Illustrated by a fulminant patient case, a multidisciplinary step-by-step guideline was developed for the recognition, diagnosis, and management of patients with severe acute portosplanchic venous thrombosis with mesenteric ischemia due to vaccine-induced immunogenic thrombotic thrombocytopenia.

Cleaner XT Rotational Thrombectomy: An Efficacious Endovascular Technique for Salvage of Thrombosed Arteriovenous Access and a 12 Month Outcome Analysis

Purpose:

This study aims to describe an efficacious method using Cleaner XT rotational thrombectomy with catheter-directed thrombolysis and drug-eluting balloon angioplasty for the salvage of thrombosed arteriovenous fistulae and grafts.

Materials and Methods:

Retrospective analysis of all patients with thrombosed hemodialysis accesses who underwent endovascular salvage using the Cleaner XT rotational thrombectomy system at a single institution between June 2019 and September 2020 was performed. Patency was presented as Kaplan-Meier survival curves, and regression analysis was performed to examine predictors of postintervention primary patency and assisted primary patency based on Cox proportional-hazards model.

Results:

Thirty-four patients with thrombosed accesses underwent Cleaner XT rotational thrombectomy between June 2019 and September 2020. Technical and clinical success were both 100%. Mean procedure time was 62 ± 20 minutes. Mean postintervention primary patency time was 152 ± 51 days; 30, 90, 180, and 365 day postintervention primary patency rates were 89%, 80%, 68%, and 56%, respectively. Mean postintervention-assisted primary patency time was 157 ± 59 days; 30, 90, 180, and 365 day postintervention-assisted primary patency rates were 91%, 82%, 71%, and 59%, and 180 and 365 day secondary patency rates were 97.2% and 94.4%, respectively.

Conclusion:

The Cleaner XT rotational thrombectomy device demonstrates excellent clinical and technical success rates, with good patency results at all time points up to 12 months postintervention.

Endovascular Management of Thrombosed Dialysis Vascular Circuits

A functional hemodialysis vascular access is the lifeline for patients with end-stage kidney disease and is considered a major determinant of survival and quality of life in this patient population. Hemodialysis therapy can be performed via arteriovenous fistulas, arteriovenous grafts, and central venous catheters (CVCs). Following dialysis vascular access creation, the interplay between several pathologic mechanisms can lead to vascular luminal obstruction due to neointimal hyperplasia with subsequent stenosis, stasis, and eventually access thrombosis. Restoration of the blood flow in the vascular access circuit via thrombectomy is crucial to avoid the use of CVCs and to prolong the life span of the vascular access conduits. The fundamental principles of thrombectomy center around removing the thrombus from the thrombosed access and treating the underlying culprit vascular stenosis. Several endovascular devices have been utilized to perform mechanical thrombectomy and have shown comparable outcomes. Standard angioplasty balloons remain the cornerstone for the treatment of stenotic vascular lesions. The utility of drug-coated balloons in dialysis vascular access remains unsettled due to conflicting results from randomized clinical trials. Stent grafts are used to treat resistant and recurrent stenotic lesions and to control extravasation from a ruptured vessel that is not controlled by conservative measures. Overall, endovascular thrombectomy is the preferred modality of treatment for the thrombosed dialysis vascular conduits.

Modified lyse and wait technique for the treatment of dialysis fistula thrombosis: Percutaneous thrombolytic therapy with a 27-G dental needle

BACKGROUND

The lyse and wait technique is a percutaneous endovascular technique in the treatment of thrombosed dialysis fistulas. In this study, our aim was to introduce a more easily applicable modification of the lyse and wait technique and present our results.

METHODS

A total of 84 patients (56 male; 66.6%), with a mean age of 61 years, were included in the study. The treatment was performed in patients presenting with dialysis fistula thrombosis no more than 1 week before the procedure, whose thrombosed segment length was less than 10 cm. A 27-G dental needle was inserted into the thrombosed segment under ultrasonography guidance, and 5 mg of alteplase was injected in a controlled manner. After about 6 to 12 h, the patients were taken to the angiography unit, and balloon angioplasty was performed.

RESULTS

The technical and clinical success of the procedure was 98.8%. Technical and clinical failure occurred in only one patient. The median primary patency duration was 13.5 months. None of the patients had major complications. At the end of 12 months, the primary patency rate was 66.6%, and the secondary patency rate was 80%.

CONCLUSIONS

Our technique has shown to have high technical and clinical success and patency.

Application Value and Relevance Analysis of the Risk Evaluation System for Arteriovenous Fistula Puncture in Thrombosis after Puncture

Objective

To analyze the application value and relevance of risk evaluation system for arteriovenous fistula (AVF) puncture in thrombosis after puncture.

Methods

The clinical data of 180 patients treated with hemodialysis in the hemodialysis center of our hospital from November 2017 to November 2019 were retrospectively analyzed. After puncture, all patients received the digital subtraction angiography (DSA) examination, and based on whether they had AVF thrombosis, they were divided into the nonthrombosis group (n = 102) and thrombosis group (n = 78), and then, according to the parity of their admission numbers, the patients in the thrombosis group were subdivided into the study group (n = 39) and the reference group (n = 39), so as to analyze the risk factors of thrombosis after AVF puncture and the application value of the risk evaluation system for AVF puncture in preventing and treating thrombosis.

Results

Compared with the reference group after intervention, the study group had significantly higher mean internal fistula blood flow volume (P < 0.001) and significantly lower total incidence rate of vascular complications in fistulas (P < 0.05); according to the multifactor binary logistic regression analysis, it was found that diabetes, systolic blood pressure reduction, hemoglobin, low-density lipoprotein cholesterol (LDL-C), ultrafiltration rate, and elevation of blood phosphorus and platelet levels were the risk factors of thrombosis after AVF puncture in hemodialysis patients.

Conclusion

When risk factors of thrombosis are found in patients treated with hemodialysis, timely detection and intervention shall be applied in the early stage. Adopting the AVF puncture risk evaluation system has an extremely high application value in the clinic and is of important meaning in prolonging the service life of fistulas.

Bench thrombolysis and "autotransplantation" as a rescue treatment for venous thrombosis after living-donor kidney transplantation

BACKGROUND

Allograft venous thrombosis is a severe complication after kidney transplantation (KT). Early diagnosis and prompt treatment are crucial in preserving the survival of the allograft. In this study, we aimed to describe an emergent strategy for the management of acute allograft venous thrombosis.

CASE PRESENTATION

A 4-year-old girl, weighing 13.5 kg, was diagnosed with bilateral congenital renal hypodysplasia, urogenital sinus and anorectal malformation. The patient was referred to our department for living-donor KT. Her mother was eligible as a donor, presenting a body weight ratio of 1:4.5. Thrombosis of the inferior vena cava (ICV) was also identified, without any predisposing factor for thrombophilia. KT was performed by an extraperitoneal approach without complications. Venous anastomosis required a human vascular graft sutured to the ICV, and renal artery was anastomosed to the aorta. On postoperative day (POD) 8, acute abdominal pain and hematuria led to the diagnosis of an allograft venous thrombosis. An emergent laparotomy was required to explant the allograft, followed by bench surgery. The allograft was irrigated with thrombolytic agents and lactated Ringer's solution and then after removing the venous vascular graft, it was reimplanted through vascular anastomosis with the ICV and aorta. The recovery of perfusion and function was good with diuresis since day 4 after re-surgery. At 2-year follow-up, the child presented normal allograft function with an estimated GFR of 65 ml/min/1.73 m² .

CONCLUSION

According to our experience, explantation of the kidney allograft, followed by irrigation with thrombolytics in bench surgery, and reimplantation resulted in unexpected optimal outcomes in the case of allograft venous thrombosis.

[Complications of permanent vascular access for haemodialysis]

Permanent vascular access is the basis of renal replacement therapy by the method of programmed haemodialysis, on whose stable functioning depends the life of patients with end-stage renal disease. At the present time, there is significant deficit of scientific and methodological Russian-language literature on this problem, with no Russian consensus documents concerned. This article is a review of the contemporary world literature dedicated to the problem of permanent vascular access, including currently in force European (2018) and North American (2019) guidelines for good clinical practice, also discussing the problems of strategy and tactics of creating a permanent vascular access, monitoring its dysfunction, pathophysiology of functioning of arteriovenous fistulas. Presented herein are unified approaches to diagnosis and treatment of thrombolytic and haemorrhagic complications associated with the access, as well as local infectious and non-infectious complications. Special attention is paid to indications for the operation and rational therapeutic decision-making.

The Cleaner XT™ Device as an Endovascular Adjunct for Pharmacomechanical Thrombolysis of Thrombosed Arteriovenous Fistulas and Grafts

Objective: This paper documents our experience using the Cleaner XT™ device (Argon Medical Devices, Plano, TX, USA) for pharmacomechanical thrombolysis (PMT) of thrombosed haemodialysis arteriovenous grafts (AVG) and fistulas (AVF). Materials and Methods: This was a retrospective case series (n=17) over six months at Singapore General Hospital. We evaluated demographics, procedural data, technical and procedural success, patency rates and complications. Results: There were 8 (47%) males and the patients' mean age was 66 (± 5.7) years. The mean age of AVF/AVG was 1605 (± 1099) days. All procedures were performed under local anaesthetic. PMT was performed within a mean time of 40 (±34.3) hours from the presentation. Technical, clinical and procedural success was 15/17 (88%). The thrombolysis agents used were tissue plasminogen activator (52.9%) and urokinase (41.2%). Mean primary patency time was 114 (± 116) days, with a 65% 1-month and 47% 3-month primary patency rates. The mean secondary patency time was 155 (±132) days, with 76% one-month and 65% three-month secondary patency rates, respectively. AVF rupture occurred in 3/17 (18%) cases but did not involve loss of the access circuit. Conclusion: The Cleaner XT™ device is a safe, minimally invasive endovascular tool for PMT in thrombosed AVF/AVG, with relatively high success and low complication rates.

Effect of short-term low molecular weight heparin on patency following successful salvage of arteriovenous access with recurrent thrombosis

AIM

This study aims to investigate the effect of low molecular weight heparin (LMWH) in maintaining the patency of arteriovenous (AV) access with recurrent thrombosis.

METHODS

Following successful thrombectomy, 66 patients with recurrent thrombosis were included in the study. The primary, assisted primary and secondary patency rates of patients who received LMWH (n = 24) were compared with those who did not receive anticoagulant (n = 42) using Kaplan-Meier analysis. Cox-regression analysis was performed to investigate potential predictors of patency rates.

RESULTS

The mean dose of enoxaparin used was 40 ± 13.1 mg or 0.74 ± 0.2 mg/kg daily for a median duration of 14 (IQR 7,28) days. The mean trough anti-Xa concentrations measured after two doses of LMWH was 0.17 ± 0.13 IU/mL. Kaplan-Meier analyses for mean primary, assisted primary and secondary patency rates of LMWH vs no anticoagulation groups were 149 (95% CI: 91 - 207) vs 87 (95% CI: 42-132) days (P < .006), 230 (95% CI: 142-320) vs 107 (95% CI: 62-150) days (P = .01) and 438 (299-579) vs 294 (95% CI: 197-392) days (P = .08) respectively. LMWH remained a significant protective predictor of primary (HR: 0.49; 95% CI: 0.25-0.86; P = .02) and assisted primary patency rates (HR: 0.51; 95% CI: 0.27-0.98; P = .04) after adjusting for patient age, access age, type of AV access, presence of peripheral vascular disease and haemoglobin levels.

CONCLUSION

LMWH may improve short and mid-term patency rates for AV accesses with recurrent thrombosis.

Does reducing radiation levels for procedures affect image quality and radiation to proceduralists? A double-blinded randomised study of two protocols

AIM

To evaluate the ultra-lose dose imaging protocol (ULDP), compared to the standard low-dose imaging protocol (LDP), which are used for haemodialysis access, in terms of radiation exposure and image quality.

MATERIAL AND METHODS

This was a single-centre, institutional review board-approved, prospective, double-blinded randomised controlled study to compare radiation exposure and image quality of the ULDP and LDP. Ten proceduralists, two radiographers, and 11 nurses were enrolled. Radiation exposure during 80 procedures (40 angioplasties and 40 thrombolysis) was recorded (direct radiation to patients from protocol report and scattered radiation to participants from the RaySafe i2 real-time dosimetry system). Baseline characteristics of procedure were recorded. Image quality was assessed subjectively using questionnaires based on the five-point Likert scale after each procedure.

RESULTS

Compared with LDP, the use of ULDP was associated with a significantly lower rate of radiation exposure to proceduralists, patients, and scrub nurses (0.506±0.430 versus 0.847±0.965 μSv/s, p=0.044; 0.571±1.284 versus 1.284±1.007 mGy/s, p<0.001; and 0.052±0.071 versus 0.141±0.185 μSv/s, p=0.005, respectively). No significant difference in image quality or duration of procedure was observed (all p values >0.05).

CONCLUSION

Compared with LDP, the use of ULDP was associated with a significantly lower rate of radiation exposure to proceduralists, patients, and scrub nurses without compromising the image quality or duration of procedure.

Study protocol of a pilot study on sirolimus-coated balloon angioplasty in salvaging clotted arteriovenous graft

Background

In arteriovenous graft (AVG) for haemodialysis, the primary cause of failure is venous stenosis of the graft-vein junction from neointimal hyperplasia (NIH), resulting in thrombosis. While interventions to salvage clotted AVG are known to have high clinical success rates, long-term patency rates have been suboptimal. Drug-coated balloon (DCB) has been used to treat stenosed arteriovenous access in recent years with encouraging results but data on its effect in clotted AVG is unavailable.

Methods

This is an investigator-initiated, single-center, single-arm prospective pilot study to determine the safety and outcome of the sirolimus-coated balloon (SCB) in the salvage of thrombosed AVG. Twenty patients who undergo successful percutaneous thrombectomy will receive treatment with SCB at the graft vein junction. The patients will be followed-up for 6-months. The primary endpoint is the patency rates at 3-month while the secondary endpoints are the patency rates and the number of interventions needed to maintain patency at 6-month.

Discussion

Unremitting efforts have been made to prolong the patency of AV accesses over the years. DCB angioplasty combines mechanical and biological treatment for vascular stenosis. Sirolimus, being a cystostatic anti-proliferative agent, has been successfully used in coronary artery interventions. As the primary pathology of vascular stenosis in the dialysis circuit is neointimal hyperplasia, the use of sirolimus in balloon angioplasty may be effective. With this prospective study, we evaluate the efficacy and safety of SCB in patients with clotted AVG.

Trial registration

ClinicalTrials.gov Identifier: NCT03666208 on 11 September 2018.

Outcomes of endovascular salvage of clotted arteriovenous access and predictors of patency after thrombectomy

OBJECTIVE

This study aimed to report the outcomes of endovascular salvage of clotted arteriovenous (AV) accesses and to determine potential predictors of poor patency rates after thrombectomy.

METHODS

Records of hemodialysis patients who underwent endovascular salvage of clotted AV access were reviewed retrospectively. Technical and clinical success rates, complication rates, and 3- and 6-month patency rates were determined. Multivariate analysis was performed to determine the predictors of patency after thrombectomy.

RESULTS

A total of 294 patients underwent endovascular salvage of clotted AV access during the study period; 156 patients had arteriovenous fistula, whereas the remaining 138 were arteriovenous grafts (AVGs). The technical and clinical success rates were 96.3% and 93.2%; the major and minor complication rates were 0.7% and 9.9%. Post-thrombectomy primary, assisted primary, and secondary patency rates were 62.9%, 76.2%, and 77.6% at 3 months and 43.9%, 59.5%, and 61.6% at 6 months. The patency rates were significantly better for arteriovenous fistula than for AVG except for 6-month assisted primary and secondary patency. Multivariate Cox regression analysis showed that prior thrombosis within 90 days was significantly associated with loss of primary patency (hazard ratio [HR], 1.90; 95% confidence interval [CI], 1.21-2.98; P < .01), assisted primary patency (HR, 2.42; 95% CI, 1.42-4.13; P < .01), and secondary patency (HR, 2.52; 95% CI, 1.40-4.53; P < .01). Having an AVG was also negatively associated with primary patency.

CONCLUSIONS

Most clotted AV accesses can be salvaged by endovascular technique. Recurrent thrombosis within 90 days is associated with poor short- and long-term patency even after successful endovascular reinterventions.