The Value of Preprocedural MR Imaging in Genicular Artery Embolization for Patients with Osteoarthritic Knee Pain

Clinical question
What is the value in preprocedural MRI in genicular artery embolization (GAE) for patients with osteoarthritic knee pain?

Take away point
Large bone marrow lesions and severe meniscal injury on MRI as well as high Kellgren-Lawrence grade on plain radiograph indicated poor response to GAE.

Reference
Choi JW, Ro DH, Chae HD, Kim DH, Lee M, Hur S, Kim H, Jae HJ, and Chung JW. The Value od Preprocedural MR Imaging in Genicular Artery Embolization for Patients with Osteoarthritic Knee Pain. J Vasc Interv Radiol. 2020;31(12):2043-2050. doi.org/10.1016/j.jvir.2020.08.012

Click here for abstract

Study design
Single-institution retrospective study of 28 knees in 18 patients undergoing GAE for osteoarthritic knee pain.

Funding Source
National Research Foundation of Korea (grant no. NRF-2018R1D1A1A02086183).

Setting
Academic hospital, Seoul National University Hospital, South Korea.



Figure. Numbers of knees that showed > 30% reduction in pain scores at 1 and 3 month follow up following GAE based on (a) KL grades on plain radiographs, (b) BML grades on MRI, and (c) meniscal injury grades on MRI.

Summary

Geniculate artery embolization (GAE) is a relatively new treatment for osteoarthritic knee pain with little known about the ideal indications for the procedure. Given that the genicular arteries supply soft tissue structures of the knee, the authors hypothesized that MR imaging could add value to preprocedural assessment of indications for GAE in addition to the known Kellgren-Lawrence (KL) grading system based on plain radiography. The authors performed a retrospective study of 28 knees in 18 patients treated with GAE with 1 and 3 month follow up data.

Patients presenting with osteoarthritic knee pain of over 6 moths duration despite conservative therapy were assessed for GAE. Knees without an MRI within 1 month of treatment or with diagnoses other than osteoarthritis were excluded. Additionally, one patient with knee replacement surgery within the follow up period and one patient who did not follow up were also excluded.

Prior to GAE, patients ranked their pain for each affected knee based on a 100-mm visual analog scale (VAS). Prior to the procedure, knees were evaluated by an orthopedic surgeon and pain was localized via physical exam and denoted with radiopaque markers. During the procedure, the genicular arteries that most closely supplied the marked areas were embolized. If pain was diffuse or unable to be localized, the genicular arteries exhibiting abnormal hypervascular staining on digital subtraction angiography (DSA) were embolized. At 1 and 3 month follow up visits, patients again ranked their pain in each affected knee on the same 100-mm VAS.

KL grades were assigned based on preprocedural radiographs reviewed by a musculoskeletal radiologist. Preprocedural MRIs were reviewed twice (at 3 months apart) by a single, blinded, musculoskeletal radiologist with specific grading of 6 parameters including: cartilage defects (scored 0-3 based on deepest loss among lesions), osteophytes (scored 0-3 based on length of extrusion from the cortex), subchondral cysts (scored 0-3 based on largest diameter), bone marrow lesions (BML; scored 0-3 based on largest diameter), meniscal injury (scored 0-4 based on tear morphology and severity), and joint effusion (scored 0-3 based on number of distended synovial recesses). Intra-observer disagreements were reviewed by a second musculoskeletal radiologist.

A total of 28 knees in 18 patients met criteria with preprocedural VAS pain scores ranging from 30-100 (mean 84.3; SD 15.5). Three of the graded imaging parameters were significantly related to GAE response (defined as a reduction in VAS pain score by > 30%): KL grade (p<.001), BML grade (p<.001), and meniscal injury grade (p=.003). With a cutoff of ≤ 2 for each significant parameter, sensitivity and specificity in predicting GAE response were as follows: 100% and 68.2% for KL grade, 83.3% and 77.3% for BML grade, and 83.3% and 72.7% for meniscal injury grade.

Commentary

The authors investigate the value of preprocedural MRI in a relatively small cohort of patients undergoing GAE for osteoarthritic knee pain. The authors discuss that the value in preprocedural MRI likely lies in identifying potential GAE nonresponders rather than patients who will benefit from treatment. The significant parameters of KL, BML, and meniscal injury grade are hypothesized as indicators of bone-centered pain, which is less likely to be adequately treated with GAE. Of note, the authors mention that although the menisci are soft tissue structures, they are not supplied by nerves, and therefore meniscal injury noted on MRI was felt to represent bone-centered pain via degenerative joint-space narrowing. Similarly, cartilaginous defects, although not statistically significant, were also associated with poor GAE response. There are several limitations with this study; most notable are its small sample size and lack of control group. Patients with prior surgical treatments were included in the study, and although the most recent surgery was 9 months prior to GAE, the clinical significance of prior surgery remains unclear without a comparison group. Additionally, the applicability of the findings is limited given the time-consuming grading of parameters on each knee MRI, which are not currently standard reported findings. Overall, this study is a useful initial exploration into the value of preprocedural imaging for GAE, which remains a relatively novel therapy and merits future investigation.

Post Author
Catherine (Rin) Panick, MD
Resident Physician, Integrated Interventional Radiology
Dotter Interventional Institute
Oregon Health & Science University
@MdPanick

Endovascular Outcomes in Aortic Arch Repair with Double and Triple Parallel Stent Grafts

Clinical question
How do early and midterm outcomes of patients with thoracic aortic aneurysm (TAA) or aortic dissection (AD) involving zones 0 or 1 compare when treated with double versus triple parallel stent grafts (PSGs)?

Take-away point
Patients who underwent TPSG repair had increased incidence of adverse events without increase in mortality or need for secondary procedures than patients who underwent DPSG repair.

Reference
Guo B, Guo D, Chen B, et al. Endovascular Outcomes in Aortic Arch Repair with Double and Triple Parallel Stent Grafts. J Vasc Interv Radiol. 2020;31(12):1984-1992.e1.

Click here for abstract

Study design
Retrospective cohort study

Funding source
Sponsored by the Shanghai Sailing Program (18YF1404000), National Natural Science Foundation of China (81770474, 81770508), and Excellent Young Talents Fund Program of Zhongshan Hospital Fudan University (2019ZSYQ26).

Setting
Zhongshan Hospital, Shanghai, China.



Figure 2. Technical conduct and follow-up outcome of TEVAR with DPSGs for non-A, non-B aortic dissection. (a, b) Preoperative CT scan (a) and angiogram (b) showing the proximal entry tear located in the ostium of the LSA, with retrograde dissection extending into zone 0. (c, d) Two anterograde PSGs in the innominate artery and left common carotid artery had been delivered through the bilateral common carotid arteries and placed in parallel with each other after some adjustments with the wires and catheters. (e) Both PSGs were simultaneously deployed following implantation of the aortic endograft. Typically, 2 coaxial stent grafts without crossing are deployed because of concerns about durability in this configuration. (f) In this case, the LSA was planned to be covered without embolization or revascularization, and the angiogram indicated no endoleak on completion. (g) CT scan at 3 months after TEVAR demonstrated a slight type II endoleak. (h) The endoleak had sealed completely after 27 months.

Summary

Thoracic endovascular aortic repair (TEVAR), a minimally-invasive technique for the treatment of aortic disease, often requires augmentation when supra-aortic branches are involved. One of these augmentation techniques, the chimney technique, encompasses the use of parallel stent grafts (PSGs) to maintain communication between the aorta and supra-aortic branches. While originally used to rescue the left subclavian artery after inadvertent covering during TEVAR, the technique has been progressively adopted as a technique for proximal aortic disease. Long-term data on the techniques’ efficacy, however, is lacking.

In this retrospective cohort study, all patients with aortic dissection or thoracic aortic aneurysm who had underwent endovascular repair over a 7-year period were evaluated. Of these 1806 patients, 31 had underwent TEVAR with multiple PSGs for zone 0 or 1 disease. Of these 20 were treated with double parallel stent grafts (DPSGs) and 11 were treated with triple parallel stent grafts (TPSGs). Follow-up consisted of surveillance imaging at 1, 6, and 12 months as well as annually after the first year, in addition to additional imaging as warranted by new symptoms or adverse events. Outcome variables assessed included all-cause mortality, major adverse events including aortic rupture, endoleaks, endograft migration, retrograde type A aortic dissection, PSG stenosis or occlusion, and stroke.

48.4% of patients underwent urgent/emergent TEVAR for symptomatic or acute aortic disease. 61.3% of patients underwent repair for zone 0 disease. In terms of outcomes within 30 days of the procedure, type Ia endoleak occurred in 30% of DPSG repair and 45.5% of TPSG repairs (p=0.45). No endograft migrations were observed. One interoperative death occurred in a patient undergoing DPSG repair. No additional deaths were reported within 30 days of the procedures. Technical and clinical success was achieved in 70% of DPSG repairs and 45.5% of TPSG repairs. Minor strokes were reported in 36.4% of TPSG repairs versus 5% of DPSG repairs (p=0.042, 16.1% of all patients). There were no differences in length of hospital or ICU admissions between the two cohorts.

Mean follow-up was 28.9 months with a range of 4.8 to 68.6 months. No cases were lost to follow-up. Overall mortality was 12.9% and aorta-related mortality was 6.5%. There were no significant differences in all-cause mortality between cohorts. 41.9% of patients experienced major adverse events, which occurred in 72.7% of TPSG cases and 25% of DPSG cases (p=0.021). Most common major adverse events were endoleaks (12.9%), endograft migration (9.7%), PSG stenosis/occlusion (6.5%), retrograde dissection (6.5%), and stroke (3.2%). All endograft migrations occurred in the TPSG cohort. There was no significant difference in secondary interventions or need for additional interventions between cohorts. Overall mortality was 16.1% over the perioperative and follow-up period without significant differences between cohorts.

Commentary

This study provides a comparison between repairs using both DPSGs and TPSGs in TEVAR for aortic disease involving zone 0 and 1. It demonstrated a statistically-significant increase in major adverse events, including 30-day minor stroke and endograft migration, in the TPSG group. This study is limited, however, for multiple reasons including small sample size, lack of comparison to single PSG repair or open surgical repair, as well as analysis of differences between different variations in PSG technique (e.g. landing zones). While patient capture is likely difficult and there is a significant selection bias involved is choice of number of PSGs placed based on case-specific details, larger multicenter studies will allow for more robust statistical comparison and subgroup analysis in order to draw more concrete conclusions.


Post Author
Jared Edwards, MD
General Surgery Intern (PGY-1)
Department of General Surgery
Naval Medical Center San Diego, San Diego, CA
@JaredRayEdwards

Prospective Study of Systemic Yttrium-90 Elution during Radioembolization of Hepatic Metastases

Clinical question
Does blood radioactivity differ based on Y90 delivery method?

Take away point
Y90 delivery with 50% contrast in saline solution resulted in a significant blood radioactivity increase compared to delivery in D5W.

Reference
Alexander ES, Pantel AR, Carlin SD, Beckmann N, Mick R, Pryma DA, Soulen MC. Prospective Study of Systemic Yttrium-90 Elution during Radioembolization of Hepatic Metastases. J Vasc Interv Radiol. 2020 Dec;31(12):2007-2013.e1. doi: 10.1016/j.jvir.2020.08.011. Epub 2020 Nov 2. PMID: 33143997.

Click here for abstract

Study design
Single center prospective

Funding Source
None

Setting
Academic hospital. University of Pennsylvania, Philadelphia, PA

Figure


Figure. Fraction of free 90Y in the blood was significantly higher for patients treated with dilute contrast medium than in those treated with D5W (median, 0.5% of injected activity vs 0.2%; P 1⁄4 .001).

Summary

Manufacturers advise administering Y90 with D5W or sterile water to avoid exposing the resin microspheres to ionic solutions. Because Y90 is incorporated on the resin microspheres by an ion exchange reaction, exposure to ionic solutions may elute Y90 from the microsphere and lead to systemic delivery. Administration with sterile water or D5W and using intermittent contrast injection hinders real time monitoring and may increase the risk of non-target delivery due to early stasis or reflux. An alternative is to administer the microspheres with a nonionic contrast instead of D5W or sterile water, to allow real time visualization. The purpose of this investigation was to estimate and compare blood radioactivity after resin microsphere Y90 delivery flushed with dilute nonionic contrast compared to D5W

The authors prospectively evaluated 20 patients with hepatic metastases during their first Y90 radioembolization treatment. Y90 was dosed via the body surface area method. Microspheres were delivered either by flushing with D5W and intermittent contrast injection per the manufacturer instructions or by flushing with dilute 50% Isovue 300 in saline. Blood was drawn prior to the treatment, immediately after Y90 delivery, and at 10, 20, 60, and 120 minutes after Y90 delivery. Patients were observed for 1 month to evaluate for adverse events. Blood samples were analyzed using a gamma counter to measure counts per minute. The percent of radioactivity elution in the blood was calculated.

10 participants received Y90 with D5W and 10 participants received Y90 with diluted 50% Isovue 300. The percentage of free Y90 in the blood was significantly greater in subjects who received Y90 with Isovue 300 compared to D5W. Y90 flushed with dilute 50% Isovue was associated with shorter fluoroscopy times and lower air kerma compared to delivery with D5W . Technical success rate was 100%. One D5W treatment and two Isovue treatments were terminated early for stasis. There were zero immediate procedural complications. 12 participants experienced an adverse event at one month, eight of which were postembolization syndrome.

Commentary

The authors prospectively evaluated 20 patients receiving Y90 with either D5W, as per the manufacturer’s recommendation, or with Isovue 300 mixed with saline. Interestingly, the fraction of free Y90 in the blood was higher when the dose was flushed with Isovue 300, as the nonionic contrast should not theoretically contribute to Y90 elution. However, as the authors described, the blood radioactivity difference is of uncertain clinical significance because of the small absolute dose. Further, the increase in blood radioactivity may be offset to a degree by the decrease in fluoro time. Also, this study did not demonstrate a discrepancy in non-target embolization or early termination for stasis between the two delivery methods, a finding that has been described in other, larger studies. If this difference does in fact exist, then the lack of real time observation and the risk of non-target embolization when delivering 90 without contrast is worrying. If found to be safe, Y90 delivery with contrast provides a solution to the problem. As the authors mention, the study is limited by the small sample size, lack of patient randomization to treatment groups, and the relatively short 2-hour sampling time compared to the 64.1 hour Y90 half-life. Further evaluation with a larger, randomized cohort, and lengthier blood radioactivity analysis, would help to better clarify the safety and feasibility of Y90 delivery with dilute contrast as a solution.

Post Author
Maxwell Cretcher, D.O.
Integrated Interventional Radiology Resident, PGY-4
Department of Interventional Radiology
Dotter Interventional Institute, Oregon Health and Science University
@MCretcher

血栓切除术和涂层球囊联合治疗股腘动脉非栓塞性闭塞

经皮旋转血栓切除术和药物涂层球囊联合治疗股腘动脉非栓塞性闭塞：12个月的随访

临床问题
机械血栓切除术（使用Rotarex导管）与药物涂层球囊血管成形术联合治疗对股腘动脉闭塞是否安全和有效？

要点
旋转机械血栓切除术和药物涂层球囊结合使用可有效治疗股腘动脉闭塞。但是，相当一部分患者因发现动脉夹层或剩余狭窄大于30%而需要支架置入。

原文
Qi Wang, Ren-Ming Zhu, Hua-Liang Ren, Rui Leng, Wang-De Zhang, and Chun-Min Li. Combination of Percutaneous Rotational Thrombectomy and Drug-Coated Balloon for Treatment of Femoropopliteal Artery Nonembolic Occlusion: 12-Month Follow-up. J Vasc Interv Radiol. 2020;31(10):1661-1667.

Click here for abstract

研究设计
回顾性队列研究

资金来源
自筹资金或无资金来源

研究环境
首都医科大学附属北京朝阳医院和首都医科大学附属北京友谊医院，中国北京

图1 – 用Rotarex导管进行机械血栓切除和药物涂层球囊结合治疗股浅表动脉完全闭塞。a）数字减影血管造影显示股浅动脉闭塞（箭头）。b）用6F Rotarex导管第二次交叉后股浅动脉重通（箭头）。c）股浅动脉药物涂层球囊血管成形（星号）。d）最终血管造影成像。

总结

本文旨在评估经皮机械血栓切除和药物涂层球囊血管成形联合治疗急性和亚急性股腘动脉闭塞疾病的安全性和有效性。

股腘动脉闭塞性疾病的当前治疗指导方案包括外科手术干预和导管溶栓治疗。但是导管血栓切除或者外科搭桥以及两者所需的全身麻醉，都有一定的并发率和死亡率；而导管溶栓也有可能造成重大出血，留下血液流动或神经系统方面的后遗症。因此对于有多种并发症和高龄的患者人群，微创安全的替代治疗方案更加适宜。

在本篇文章中，作者回顾性分析了大约两年时间内接受Rotarex导管血栓切除和紫杉醇涂层球囊导管成形联合治疗，无间断的患者人群。总共包含81例经彩色多普勒超声或CT血管造影诊断为急性至亚急性股腘动脉闭塞性疾病，且不适宜进行外科手术的患者。微创手术过程中，会先使用Rotarex导管进行两次血栓切除，然后无涂层球囊预扩张，接着进行药物涂层血管成形。如果发现显著动脉夹层或者成形后狭窄仍然大于30%，自扩张的镍钛合金裸支架会被置入；如果剩余血栓明显，则会通过Unifuse输液导管进行额外的溶栓治疗。

在所有81例患者中，57例（70.3%）仅使用经皮机械血栓切除术便实现了血管再通；14例（17.3%）需要支架置入；10例（12.3%）因血栓残留而需要额外的溶栓治疗。没有患者出现重大不良事件；但有11例患者有轻微并发症，包括自限性动脉夹层（5/81），动脉远端栓塞（4/81），和动脉穿孔（2/81）。以上并发症都在发现后得到了成功的治疗。共有71名患者完成了12个月的随访。初级通畅率为87.3%（62/71）。9.9%的患者需要远端输血目标通血重建。3%的患者出现了动脉狭窄复发。为期12个月的随访中，踝肱指数恢复显著，从术前的0.46 ± 0.15恢复至术后12个月的0.77 ± 0.14（p小于0.01）。

评论

与旋转血栓切除联合无涂层球囊血管成形相比，使用Rotarex导管与药物涂层球囊血管成形结合治疗的结果优越，安全，且复发狭窄率低。原文作者承认他们的研究存在一定的局限性，包括回顾性分析，患者数量少，无对照组，随访时长1年和不适宜外科手术患者群的选择性偏见。另外，作者并没有对使用Rotarex导管血栓切除术所必需的技巧进行详细阐述，仅在手术描述段落一笔带过；本博客作者认为使用Rotarex导管有不低的技术门槛，在不太熟悉的操作员手中使用结果可能会与原文中提供的数据有所不同。但总的来说，原文作者提出了令人信服的临床数据和结论，为更加大型的前瞻性随机对照试验做好了铺垫，以更进一步地探讨微创技术如何和当前外科手术治疗手段相辅相成。

博文作者

Greg Rufener 医学博士
放射科住院医师（PGY-3）
俄勒冈健康与科学大学

@ gregoryrufener

翻译作者
李宁成 医学博士 生物工程硕士
放射介入住院医师（PGY-4）
俄勒冈健康与科学大学

@NingchengLi

Rotational Thrombectomy and Drug-Coated Balloon for Femoropopliteal Artery Nonembolic Occlusion

Combination of Percutaneous Rotational Thrombectomy and Drug-Coated Balloon for Treatment of Femoropopliteal Artery Nonembolic Occlusion: 12-Month Follow-up

Clinical question
Is mechanical thrombectomy (using the Rotarex catheter) combined with drug-coated balloon angioplasty safe and effective for treatment of femoropopliteal occlusive disease?

Take-away point
The combination of mechanical thrombectomy with Rotarex and DCB is effective for femoropopliteal occlusions; however, a significant number of patients required bailout stenting.

Reference
Wang, Qi, et al. Combination of Percutaneous Rotational Thrombectomy and Drug-Coated Balloon for Treatment of Femoropopliteal Artery Nonembolic Occlusion: 12-Month Follow-up. J Vasc Interv Radiol. 2020;31(10):1661-1667.

Click here for abstract

Study design
Retrospective cohort study

Funding source
Self-funded or unfunded

Setting
Two academic centers, Beijing China




Figure 1. Total occlusion of the superficial femoral artery treated by mechanical thrombectomy with the Rotarex catheter and DCB. (a) Digital subtraction angiograph shows occlusion of the superficial femoral artery (arrow). (b) Recanalization of superficial femoral artery after second crossing with 6-F Rotarex catheter (arrow). (c) DCB angioplasty of the superficial femoral artery (asterisk). (d) Final angiography after DCB dilation.

Summary

This article aimed to evaluate the safety and efficacy of percutaneous mechanical thrombectomy in combination with a drug-coated balloon angioplasty for treatment of acute and subacute femoropopliteal artery occlusive disease.

The current standard of care for femoropopliteal arterial occlusive disease is open surgical intervention or catheter directed thrombolysis. Balloon catheter thrombectomy or surgical bypass possess significant morbidity and mortality related to both the procedure and general anesthesia. Catheter directed thrombolysis presents with risk of hemodynamically or neurologically significant hemorrhage. For a patient population typically presenting with multiple comorbidities and advanced age, a minimally invasive, safer alternative is desirable for treatment of femoropopliteal arterial occlusive disease.

Consecutive treatment with the Rotarex catheter and a paclitaxel coated balloon catheter was retrospectively reviewed over approximately a 2 year period, which included a total of 81 patients with acute to subacute femoropopliteal artery occlusive disease diagnosed by color Doppler ultrasound or CT angiography. Included patients were generally considered poor surgical candidates. Two passes with the Rotarex catheter were performed, predilation of the recanalized vessel with an uncoated balloon, followed by subsequent percutaneous transluminal drug coated angioplasty. Additional stent placement with self-expanding nitinol bare stents were used to treat significant dissections of residual stenosis greater than 30%, and additional thrombolysis was administered via a Unifuse infusion catheter if significant remaining clot burden was present. Dual antiplatelet therapy was continued for a minimum of 6 months following the procedure, followed by clopidogrel alone.

Vessel recanalization was achieved in 70.3% of patients (57/81) with percutaneous mechanical thrombectomy alone, 17.3% (14/81) with percutaneous mechanical thrombectomy and bailout stent placement, and 12.3% (10/81) had residual thrombus and required additional thrombolysis. No major adverse events were encountered. 11 minor procedure-related complications occurred, including flow limiting dissection (5/81), distal embolism (4/81), and artery perforation during thrombectomy (2/81), all of which were successfully treated when encountered. 71 patients completed the 12-month followup; primary patency rate was 87.3% (62/71), 9.9% of patients required target lesion revascularization (7/71), and 3% of patient had restenosis with mild symptoms which were managed conservatively (2/71). During the follow-up period, the ABI significantly (P < .01) improved after treatment, improving from 0.46 ± 0.15 before treatment to 0.77 ± 0.14 at 12 months.

Commentary

The authors emphasize the superiority of their results with Rotarex catheter in complication with drug coated balloon angioplasty, compared to rotational thrombectomy in combination with an uncoated balloon, which had significantly higher restenosis rates. The authors acknowledge some limitations to their study, including the retrospective nature of the study, small number of patients, no control group, limited follow up to only 1 year, and selection bias consisting of mostly poor surgical candidates. It seems that the authors downplay the technical skill necessary to use the Rotarex catheter safely and effectively, which was only touched on briefly in the procedural details when referring to “slow back-and forth movements” and “repeated retraction” of the catheter. It would seem the use of this device is more technically demanding than thrombolysis, and use in the hands of a less familiar operator could vary. Overall, the authors present a compelling argument for further investigation of rotational thrombectomy in combination with drug coated balloon angioplasty in the treatment of acute and subacute thrombus-containing femoropopliteal artery atherosclerotic occlusions. Larger prospective randomized controlled trials will need to further evaluate the growing variety and combinations of minimally invasive techniques with the current surgical standard of care.


Post Author
Greg Rufener, MD
Radiology Resident (PGY-3)
Department of Radiology
Oregon Health and Science University, Portland, Oregon
@gregoryrufener