Impact of Renal Function Trajectory on Renal Replacement Therapy and Mortality Risk after Renal Artery Revascularization

Clinical question
What is the impact of renal function trajectory, defined as the change in renal function over time before and after renal artery stent placement, on long-term risk for renal replacement therapy (RRT) and mortality?

Take-away point
Post intervention eGFR trajectory improvement approaching 40 mL/min/1.73 m2 was associated with decreased RRT and mortality risk, indicating that patients with advanced CKD and renal artery stenosis may benefit from revascularization.

Reference
Takahashi, Edwin A. et al. Impact of Renal Function Trajectory on Renal Replacement Therapy and Mortality Risk after Renal Artery Revascularization. Journal of Vascular and Interventional Radiology, Volume 31, Issue 4, 592 – 597.

Click here for abstract

Study design

Retrospective review

Funding source

Self-funded or unfunded

Setting

Single institution

Figure 1. Kaplan–Meier estimates for freedom from the need for RRT after renal artery stent placement. Fourteen patients were started on RRT, 16 died, and 9 were lost to follow-up within 1 year of intervention, resulting in an initial number at risk of 359 patients.

Summary

Evidence in support of aggressive diagnosis and revascularization of renal artery stenosis is evolving. Data on renal function trajectory is lacking. The authors of this study evaluated the effect of renal artery stenting on renal replacement therapy (RRT)-including hemodialysis and transplantation-in addition to all-cause mortality based on renal function change from 6-12 months before intervention to the time of intervention and from the time to intervention to 6-12 months after intervention.

Retrospective review of 398 patients who underwent renal artery stenting was performed. Renal artery stent placement was performed if Doppler US showed a main renal artery peak systolic velocity >180 cm/s or a renal-to-aortic radio >3.5. Angiographically, stenoses greater than or equal to 50% were treated with angioplasty followed by balloon-expandable bare-metal stent placement without distal embolic protection. Bilateral renal artery stenosis was treated in 162 patients (41%). Primary outcome was impact of estimated glomerular filtration rate (eGFR) on the incidence of RRT and mortality. Potential contributing factors to RRT such as medications, 24-hour proteinuria, presence of CKD, coronary artery disease, diabetes, and smoking were analyzed.

Of the 398 patients, 14 started RRT, 16 died, and 9 were lost to follow-up within 1 year of the procedure. The RRT-free survival rate at 5 years was 92.1% (95% CI, 88.0%–96.1%). 248 patients died after 6–12-month post-intervention (5 year mortality risk of 60.3%). Mean pre-interventional, time-of-intervention, and post-interventional eGFR measurements were 48.3 mL/min/1.73m2±18.7, 42.5 mL/min/1.73 m2±17.8, and 45.5 mL/min/1.73 m2±20.1, respectively. The eGFR trajectory from 6–12 months before intervention to the time of intervention was not significantly associated with risk for RRT or all-cause mortality (P=.47 and P=.45, respectively). However, the eGFR trajectory from intervention to 6–12 months after intervention was significantly associated with freedom from RRT (P=.02). This change was not associated with freedom from all-cause mortality (P=.21). Among patients with a post-interventional eGF<40 mL/min/1.73 m2, for a 1-unit eGFR increase up to 40 mL/min/1.73 m2, there was a significant decrease in RRT risk (HR, 0.87; 95% CI, 0.83–0.91; P<.001) as well as all-cause mortality risk (HR,0.95; 95% CI, 0.94–0.97; P<.001). However, patients with an eGFR>40 mL/min/1.73 m2 at 6–12 months after intervention did not experience lower incidences of RRT or death. Higher rates of RRT were seen with diabetes at the time of intervention, increased baseline proteinuria, and stage 4/5 CKD. On univariate analysis, higher mortality rates were seen in patients with diabetes, increased baseline proteinuria, and stage 4 CKD. On multivariate analysis, higher mortality was seen with diabetes was the only comorbidity associated with increased mortality.

Commentary

Following the CORAL trial, it is encouraging to see data which may support a greater role for renal artery stenting for renovascular hypertension. The main finding of this study is that eGFR less than or equal to 40 mL/min/1.73 m2 after intervention has a beneficial effect on RRT and mortality. However, this study does have limitations in that the criteria for and severity of hypertension and renal dysfunction were not described and that hemodynamic significance of renal artery lesions were determined by a threshold of 50% or more stenosis on angiography, without pressure measurements. Dr. Sos discusses these limitations and others in a thorough commentary. More work on renal artery stenting in the form of large, prospective, randomized trials are necessary.

Post Author
Zagum Bhatti, MD
Assistant Professor
Department of Radiology, Interventional Radiology Division
University of Texas Health Science Center at Houston, Houston, TX
@ZagumBhatti

Efficacy and Safety of Ultrasound-Guided Supraclavicular Brachial Plexus Block during Angioplasty of Dysfunctional Arteriovenous Access: A Prospective, Randomized Single-Center Clinical Trial

Clinical question
Is ultrasound-guided supraclavicular brachial plexus block (BPB) helpful in reducing pain prior to angioplasty of dysfunctional arteriovenous (AV) access?

Take-away point
Patients randomized to supraclavicular BPB prior to intervention on their AV access showed lower average pain scores with better patient satisfaction compared to the control group with no major immediate or delayed complications.

Reference
Heo, S., Won, J. H., Kim, J., Kim, J. Y. & Joe, H. B. Efficacy and Safety of Ultrasound-Guided Supraclavicular Brachial Plexus Block during Angioplasty of Dysfunctional Arteriovenous Access: A Prospective, Randomized Single-Center Clinical Trial. J. Vasc. Interv. Radiol. 31, 236–241 (2020).

Click here for abstract

Study design

Single-center prospective clinical trial of 80 participants between November 2016 and February 2018 randomized to either ultrasound-guided supraclavicular BPB or no regional anesthesia. Primary endpoints included pain assessment and patient satisfaction evaluation. Secondary endpoints included AV access patency at 6-month follow up as well as short- and long-term complications.

Funding source
N/A

Setting

Departments of Radiology and Anesthesiology and Pain Medicine at Ajou University School of Medicine, Suwon, Korea

Figure 2. Ultrasound-guided BPB procedure. The 23-gauge needle is first advanced to the inferior border of the brachial plexus (a), and 15 ml of anesthetic mixture is injected, resulting in superficially floating plexus bundle (b). The needle is then directed to the superior border of the brachial plexus, injecting another 15 ml of mixture (c). The procedure results in complete encasement of the brachial plexus by the injected mixture (d). M = medial; L = lateral.

Summary

Percutaneous balloon angioplasty of AV access is often painful. While moderate sedation can help alleviate pain during intervention, these medications can be associated with respiratory depression in an otherwise high-risk patient population. This study was developed to evaluate the anesthetic effect and safety of ultrasound-guided supraclavicular BPB for pain control during angioplasty of dysfunctional dialysis access—a method frequently utilized during upper extremity surgery.

Eighty participants with either insufficient flow or no flow in their upper extremity AV fistula or graft were randomized to supraclavicular BPB prior to angioplasty versus a control group. All procedures including BPB and dialysis access angioplasty were performed by the same two interventional radiologists who were not involved in the randomization process. There was no significant difference between groups regarding the reason for dialysis access dysfunction (P= .29) or the type/location of access (P=.82).

A mixture of 10 cc 0.75% ropivacaine, 10 cc of 2% lidocaine and 10 cc of normal saline was utilized for the purposes of supraclavicular BPB administered via the “double injection” technique at both the inferior and superior aspects of the plexus under ultrasound guidance. Procedure success was determined by motor and sensory changes to 0. Time to full block as well as time to recovery from motor and sensory deficit was recorded. Pain in the control group was managed with intravenous administration of 50 mg Tramadol and 5-10 cc of 2% lidocaine subcutaneous injection at the puncture site.

Procedure-related pain was evaluated by the Visual Analogue Scale from 0 (no pain) to 10 (unbearable pain) in both groups. Patient satisfaction was evaluated by a grade from 1 (not satisfied) to 3 (satisfied). Six-month follow up was performed either in outpatient clinic or over the phone.

All BPB procedures were technically successful with an average time to complete neurologic deficit of 10.7 +/- 5.1 minutes. The average neurologic recovery time from BPB was 7 hours and 56 minutes. The visual analogue pain scale was significantly lower (P < .001) and participant satisfaction was significantly higher (P < .001) in the BPB group compared to the control. Six-month patency of the AV access was not significantly different in the two groups (P = .59). There were no major complications.

Commentary

This is the first prospective randomized trial to evaluate the safety and efficacy of supraclavicular BPB prior to angioplasty of dysfunctional dialysis access elucidating the benefits for pain management during intervention. The authors successfully demonstrated reduction in pain score and improvement in patient satisfaction with supraclavicular BPB without short- or long-term complications.

In this study protocol, supraclavicular BPB was consistently performed by the same highly experienced interventional radiologists prior to angioplasty. Similar protocols may be difficult to simulate in institutions where nerve blocks are traditionally performed by anesthesiologists who may not be readily available for assistance in the immediate periprocedural period with potential for delay of intervention. Conversely, supraclavicular BPB performed by less experienced interventional radiologists may prolong total intraprocedural time.

The primary method of intraprocedural pain management in the control group was intravenous tramadol. Since many institutions continue to utilize moderate sedation with intravenous fentanyl and versed during dialysis access interventions, direct comparison of the authors’ protocol for supraclavicular BPB and moderate sedation may be beneficial in future studies.

The authors describe potential limitations including use of a single mixture/concentration of anesthetic in the BPB group as well as potential bias resulting in prolonged recovery from motor and sensory deficit. As demonstrated by the authors, diligent patient education and monitoring must be maintained in the post-procedural period to prevent injury from nerve deficit if supraclavicular BPB is utilized.

Post Author

Teodora Bochnakova MD
Assistant Professor
Department of Interventional Radiology
Oregon Health and Science University, Portland, OR
@T_bochnakova

Factors Affecting Recurrent Deep Vein Thrombosis after Pharmacomechanical Thrombolysis and Left Iliac Vein Stent Placement in Patients with Iliac Vein Compression Syndrome

Clinical question
Are there factors associated contralateral and ipsilateral recurrent deep vein thrombosis (DVT) after thrombolysis and stent placement in patients with iliac vein compression syndrome (IVCS)? Is overextension of the stent associated with contralateral or ipsilateral recurrent DVT?

Take-away point
Extension of iliac vein stent to the inferior vena cava (IVC) and in-stent thrombosis are associated with contralateral DVT. Thrombophilia, remaining IVC filter, and in-stent thrombosis are associated with ipsilateral DVT.

Reference
Factors Affecting Recurrent Deep Vein Thrombosis after Pharmacomechanical Thrombolysis and Left Iliac Vein Stent Placement in Patients with Iliac Vein Compression Syndrome. Kim, K.Y., Hwang, H.P., Han, Y. Journal of Journal of Vascular and Interventional Radiology (JVIR), Volume 31, Issue 4, 635-643. 

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Study design
Single arm, retrospective, single-center study of 130 patients with left lower extremity thrombosis who underwent thrombolysis and stent placement with a median follow-up of 14 months and standardized 6-month anticoagulation followed by lifelong antiplatelet therapy.

Funding source
No reported funding

Setting
Academic hospital, Jeonbuk National University Medical School and Hospital, South Korea.




Figure 1. Categorization of stent position: (a) 100% coverage from the confluence to the contralateral wall of the inferior vena cava; (b) 50%–100% coverage; and (c) less than 50% coverage. (d) A diagram illustrating the three categories, respectively.

Summary

Left iliac stent placement after pharmaceutical thrombolysis in patients with iliac vein compression syndrome (IVCS) is safe and effective. However, precise placement remains challenging. Overly caudal placement may lead to stent collapse with caudal migration. Overly cranial placement may lead to overextension into the inferior vena cava (IVC) with implications of contralateral deep vein thrombosis (DVT). Analyses with a multi-factorial approach remain scarce regarding potential contributing factors to contralateral and ipsilateral recurrent DVT.

The authors performed a retrospective single-center study of 130 patients who underwent pharmaceutical thrombolysis and iliac vein stent placement for IVCS, categorized into 3 groups based on the left iliac stent’s IVC extension (Figure 1). Patients lost to follow-up within 3 months were excluded. Hypercoagulable work up was performed in 105 patients. IVC filter was placed in 111 patients. All filters were removed within 2 months after placement. Mechanical thrombectomy was performed in mixed-stage cases. Pre-stent balloon angioplasty was followed by stent placement oversized 10-20%. All patients were prescribed anticoagulation for 6 months followed by lifelong antiplatelet therapy. Median follow-up was 14 months. Univariate and multivariate analysis were performed between clinically relevant factors and development of contralateral and/or ipsilateral DVT.

7 and 11 patients developed contralateral and ipsilateral DVT, respectively. Contralateral DVT tend to occur later compared to ipsilateral DVT (median of 26 and 1 month, respectively). 2/7 and 5/7 contralateral DVT occurred before and during the 6-month anticoagulation period, respectively. 7/11 and 4/11 ipsilateral DVT occurred before and during the 6-month anticoagulation period, respectively. In-stent thrombosis and stent location (100% overextension into IVC) were associated with contralateral DVT. Thrombophilia, remaining IVC filter, and in-stent thrombosis during follow-up were associated with ipsilateral DVT.

Commentary

The authors in this paper examined a focused group of IVCS patients undergoing pharmaceutical thrombolysis and left iliac vein stent placement with relatively standardized workup and management. Results demonstrated in-stent thrombosis was associated with contralateral and ipsilateral DVT; overextension associated with contralateral DVT; and thrombophilia and remaining IVC filter associated with ipsilateral DVT. These results suggested that overextension into the IVC should be restrained to decrease risks of contralateral DVT. In addition, earlier IVC filter retrieval may be considered to decrease risks of ipsilateral DVT. Lastly, patients with thrombotic disease may warrant more frequent follow-ups to ensure stent patency. Although limited by its retrospective nature, variety of stents and IVC filters used, and small number of recurrent DVTs, this study has provided important information on iliac stent placement location and management of patients with IVCS.

Post AuthorNingcheng (Peter) Li, MD, MS
Integrated Interventional Radiology Resident, PGY-3
Department of Interventional Radiology
Oregon Health and Science University, Dotter Interventional Institute
@NingchengLi

Minimally Invasive Image-Guided Ablation, Osteoplasty, Reinforcement, and Internal Fixation (AORIF) for Osteolytic Lesions in the Pelvis and Periarticular Regions of Weight-Bearing Bones

Clinical question
Is AORIF a safe and effective surgical alternative to treat lytic metastases in periarticular load-bearing bones?

Take-away point
AORIF is a safe and effective treatment for symptomatic osteolytic metastases in load-bearing bones.

Reference
Lee FY, Latich I, Toombs C, et al. Minimally Invasive Image-Guided Ablation, Osteoplasty, Reinforcement, and Internal Fixation (AORIF) for Osteolytic Lesions in the Pelvis and Periarticular Regions of Weight-Bearing Bones. J Vasc Interv Radiol. 2020;31(4):649–658.e1. doi:10.1016/j.jvir.2019.11.029

Click here for abstract

Study design
Single-center, prospective clinical cohort

Funding source
Research support from the National Cancer Institute and National Institute of Arthritis and Musculoskeletal and Skin Diseases

Setting
Academic hospital, Yale School of Medicine, United States.




Figure 1. Illustrated details of the AORIF procedure.

Summary

Image guided ablation, osteoplasty, reinforcement, and internal fixation (AORIF) is a technique for treating and stabilizing osteolytic bone metastases. The procedure incorporates radiofrequency ablation for cancer treatment with PMMA cement and internal screw fixation for stabilization. This minimally invasive percutaneous approach aims to provide therapy, pain relief, and stability, while avoiding the risk associated with radiation and open surgery.

This study included 23 patients with 26 consecutive symptomatic osteolytic metastases who were treated with AORIF. Three patients had more than one treatment location. Lesions were located in the pelvis, proximal femur, proximal tibia, and calcaneus. AORIF was performed using cone beam CT guidance for 21 lesions and fluoroscopic guidance for 6 lesions. Post procedural pain and function, follow up imaging, and complications were evaluated.

No complications were described with the initial wire placement, screw placement, or ablation. Two balloons ruptured, which were retrieved without further complication. There was one instance of PMMA extravasation without further related complication. No intra or post procedural blood transfusion was required. No infection, wound complication, fracture or hardware complication was reported at 30 day follow up. No patient required a secondary or revision procedure during the follow-up period (1-18 months). All patients reported improved pain and function at 2 weeks post procedure.

Commentary

The authors evaluated 23 patients treated with AORIF for symptomatic lytic bone metastases. The results are impressive with all subjects experiencing improved pain and function, as well as zero postoperative complications, and no required secondary procedures during the follow-up period. While the cases of intraoperative balloon rupture and PMMA extravasation were inconsequential, they raise awareness for potential adverse events of the AORIF procedure. The study is limited by the small cohort, single center, and lack of control arm for comparison. Despite the limitations, the study demonstrates remarkable outcomes. The study highlights various benefits of AORIF including a spectrum of different anatomic applications and approaches. AORIF offers a low risk, minimally invasive surgical alternative for the management of lytic bone metastases. This study opens the door for future studies to further validate the AORIF procedure.

Post author
Maxwell R. Cretcher, DO
Resident Physician, Integrated Interventional Radiology
Dotter Department of Interventional Radiology
Oregon Health & Science University

Safety of Therapeutic Anticoagulation with Low-Molecular-Weight Heparin or Unfractionated Heparin Infusion during Catheter-Directed Thrombolysis for Acute Pulmonary Embolism

Clinical question
Is there a significant difference in complication profile in use of therapeutic dosed low-molecular-weight heparin versus unfractionated heparin infusion during catheter directed thrombolysis?

Take-away point
No significant difference was found in complication rates between use of therapeutic dosed low-molecular-weight heparin and heparin infusion during catheter directed thrombolysis for acute pulmonary embolism

Reference
Assaf Graif et al. Safety of Therapeutic Anticoagulation with Low-Molecular-Weight Heparin or Unfractionated Heparin Infusion during Catheter-Directed Thrombolysis for Acute Pulmonary Embolism. Journal of Vascular and Interventional Radiology. April, 2020: 31; 4, 537-543.

Click here for abstract

Study design

Retrospective Review

Funding source

Self-funded or unfunded

Setting

Single-center


Figure 3. Complications

Summary

Anticoagulation dosing during catheter directed thrombolysis for pulmonary embolism (PE) remains controversial with no clear consensus between cessation of systemic anticoagulation versus therapeutic dosing versus subtherapeutic dosing. Similarly, there is no clear data to differentiate use of low-molecular-weight heparin (LMWH) versus unfractionated heparin. This study aimed to evaluate safety of therapeutic-dose anticoagulation. With a focus on hemorrhagic complications, during catheter directed thrombolysis for acute pulmonary embolism.

156 patients were identified who underwent catheter directed thrombolysis for submassive of massive acute pulmonary embolism. All patients were treated with therapeutic anticoagulation, either unfractionated heparin infusion (ptt every 6 hours with target range of 50-80 seconds) or LMWH (weight based, BID 1 mg/kg) based on physician preference. Primary endpoints were hemorrhagic complications and all complications. No significant difference in hemorrhagic complication or all complications was found between heparin infusion and LMWH groups.

Commentary

Based on this study, there does not appear to be a significant difference in complication rate between therapeutic LMWH and heparin infusion during catheter directed thrombolysis for acute pulmonary embolism. The authors compared their complication rates to those of other studies using sub-therapeutic anticoagulation without major differences. While this may suggest no increased complication rate with use of therapeutic dosing, it does not prove any benefit either.

As is often the difficulty in retrospective reviews, there is significant heterogeneity in treatments performed. While the paper focused on heparin infusion versus LMWH, there was also significant variability in the catheter directed thrombolysis procedures (unilateral versus bilateral, infusion catheter choice, clot fragmentation, thrombectomy, plasty). Additionally, 5% of patients received systemic tPA prior to thrombolysis.

Further research is necessary in this realm, specifically comparing therapeutic dosing to subtherapeutic dosing of anticoagulation while minimizing heterogeneity between treatments.

Post Author
David M Mauro, MD
Assistant Professor
Department of Radiology, Vascular and Interventional Radiology
University of North Carolina

@DavidMauroMD