Genicular Artery Embolization for Refractory Hemarthrosis following Total Knee Arthroplasty: Technique, Safety, Efficacy, and Patient-Reported Outcomes.

PURPOSE: To investigate the safety and efficacy of genicular artery embolization for treatment of refractory hemarthrosis following total knee arthroplasty. MATERIAL AND METHODS: Patients who underwent genicular artery embolization with spherical embolics between January 2010 and March 2020 at a single institution were included if they had undergone total knee arthroplasty and subsequently experienced recurrent hemarthrosis. Technical success was defined as the significant reduction or elimination of the hyperemic blush. Clinical success was defined as the absence of clinical evidence of further hemarthrosis. Clinical follow-up was performed 7-14 days after the procedure and at 3-month intervals thereafter via a telephone interview. A total of 117 embolizations, comprising 82 initial, 28 first repeat, and 7 second repeat, were performed. RESULTS: An average of 2.5 arteries was treated per procedure. The superior lateral genicular artery was the most frequently embolized. The most utilized embolic size was 100-300 µm. Follow-up was available for all patients, with a median duration of 21.5 months. 65.9%, 25.6%, and 8.5% of patients underwent 1, 2, and 3 treatments, respectively. Complications occurred following 12.8% of treatments, of which the most common was transient cutaneous ischemia. Technical success was achieved in all cases. Clinical success was achieved in 56%, 79%, and 85% of patients following the first, second, and third treatment, respectively. 83% of patients reported being either satisfied or very satisfied with the overall result. CONCLUSIONS: Targeted genicular artery embolization with spherical embolics is an effective treatment for recurrent hemarthrosis with infrequent serious complications. Repeat embolization should be considered in cases of recurrence following initial therapy.

Current Controversies in Inferior Vena Cava Filter Placement: AJR Expert Panel Narrative Review.

Despite inferior vena cava (IVC) filter practice spanning over 50 years, interventionalists face many controversies in proper utilization and management. This article reviews recent literature and offers opinions on filter practices. IVC filtration is most likely to benefit patients at high risk of iatrogenic pulmonary embolus during endovenous intervention. Filters should be used selectively in patients with acute trauma or who are undergoing bariatric surgery. Retrieval should be attempted for perforating filter and fractured filter fragments when imaging suggests feasibility and favorable risk-to-benefit ratio. Antibiotic prophylaxis should be considered when removing filters with confirmed gastrointestinal penetration. Anticoagulation solely because of filter presence is not recommended except in patients with active malignancy. Anticoagulation while filters remain in place may decrease long-term filter complications in these patients. Patients with a filter and symptomatic IVC occlusion should be offered filter removal and IVC reconstruction. Physicians implanting filters may maximize retrieval by maintaining physician-patient relationships and scheduling follow-up at time of placement. Annual follow-up allows continued evaluation for removal or replacement as appropriate. Advanced retrieval techniques increase retrieval rates but require caution. Certain cases may require referral to experienced centers with additional retrieval resources. The views expressed should help guide clinical practice, future innovation, and research.

Radiologists' Field Guide to Retrievable and Convertible Inferior Vena Cava Filters.

OBJECTIVE. Inferior vena cava (IVC) filters are commonly used in patients who are at risk for life-threatening pulmonary embolism. After the introduction of permanent devices, numerous retrievable and convertible designs became available. Inaccurate identification can lead to confusion in options for filter retrieval and anticoagulation. CONCLUSION. This article highlights device designs of retrievable and convertible IVC filters to assist interpretation of diagnostic studies.

Radiologists' Field Guide to Permanent Inferior Vena Cava Filters.

OBJECTIVE. Inferior vena cava (IVC) filters are commonly used in patients at risk for life-threatening pulmonary embolism. Since the Mobin-Uddin filter was introduced in 1967, numerous other IVC filters have been developed. Given the plethora of IVC filter types, inaccurate identification of a filter on radiographic examination can lead to confusion in the options for filter retrieval and anticoagulation. CONCLUSION. This article highlights permanent IVC designs to assist the interpretation of diagnostic studies. Accurate identification of indwelling IVC filters could have a dramatic effect on patient management regarding anticoagulant use and possibility for IVC filter retrieval and removal. Identification of filter type, filter position, presence or absence of thrombosis, filter tilt, and filter fracture should be included in interpretive reports.

Pseudoaneurysm after total knee arthroplasty: imaging findings in 7 patients.

OBJECTIVE: To describe the clinical presentation of arterial pseudoaneurysms following total knee arthroplasty (TKA) and their diagnostic imaging features on ultrasound and magnetic resonance angiography (MRA) in 7 patients. MATERIALS AND METHODS: A search of our radiology report database from 2007 to 2017 yielded 7 patients with a pseudoaneurysm diagnosed by imaging after TKA. Clinical notes and imaging were reviewed. RESULTS: All 7 patients were male and ranged in age from 53 to 68 (mean 61) years. All patients presented with a painful swollen knee and hemarthrosis within the first month following surgery. Five patients presented after primary TKA. One patient presented after explantation for septic arthritis and another after partial synovectomy for septic arthritis without explantation. Ultrasound identified the pseudoaneurysm as a hypoechoic or hyperechoic mass with a "yin-yang" appearance of turbulent arterial flow and associated complex joint effusion. On MRA, the pseudoaneurysm was a mass next to a parent artery showing avid contrast enhancement in the arterial phase that persisted into the venous phase and washed out in the late venous phase. Six pseudoaneurysms arose from lateral geniculate arteries and 1 from a medial geniculate artery. There were no popliteal artery pseudoaneurysms. Five patients were treated endovascularly, 1 patient thrombosed without intervention, and 1 patient was treated with open surgery. CONCLUSION: Pseudoaneurysm is a potential source of a painful swollen knee with hemarthrosis or a drop in hematocrit after TKA and can be identified with either ultrasound or MRA.

Percutaneous Hepatic Perfusion With Filtered Melphalan for Localized Treatment of Metastatic Hepatic Disease: A Risk Assessment.

Regional therapies for metastatic liver disease have garnered interest in recent years due to technological advances in drug delivery. A percutaneous hepatic perfusion (PHP) using a newly developed generation 2 (GEN2) filtration system was designed to mitigate systemic toxicity and cardiovascular risk associated with hepatic blood filtration during hepatic artery infusion of the chemotherapy drug melphalan. The GEN2 system was evaluated in healthy swine, and plasma samples were assessed for clinical chemistry, melphalan toxicokinetics (TK), inflammatory cytokines, catecholamines, hematological, and cardiac biomarkers. Cardiovascular safety was assessed by echocardiography, electrocardiogram, and telemetry. Toxicology parameters included clinical signs, body weight, gross pathology, and histopathology. There were no treatment-related deaths associated with the PHP procedure with GEN2 filtration, and all animals survived to scheduled necropsy. Assessment of the pharmacokinetic/TK plasma concentrations of melphalan demonstrated that the GEN2 filter was able to extract melphalan from blood with high efficiency and reduce melphalan exposure in the systemic circulation. The hemodynamic, immunosuppressive, immunotoxic, cardiotoxic, and histopathologic effects of melphalan were limited. The significant hemodynamic challenge imposed by filtration resulted in a compensatory tachycardia with supranormal left ventricular function, although no wall motion abnormalities were detected and left ventricular function remained normal. Catecholamines decreased and then quickly rebounded during washout. Transient and reversible effects of treatment on cardiac enzymes, catecholamines, and cytokines and reversible hemodynamic effects without cardiac damage indicated that PHP with melphalan was not cardiotoxic or immunotoxic under the conditions tested, due to high efficiency of the filtration system limiting exposure of melphalan to the systemic circulation.

Multicenter Trial of the VenaTech Convertible Vena Cava Filter.

PURPOSE: To demonstrate rates of successful filter conversion and 6-month major device-related adverse events in subjects with converted caval filters. MATERIALS AND METHODS: An investigational device exemption multicenter, prospective, single-arm study was performed at 11 sites enrolling 149 patients. The VenaTech Convertible Vena Cava Filter (B. Braun Interventional Systems, Inc, Bethlehem, Pennsylvania) was implanted in 149 patients with venous thromboembolism and contraindication to or failure of anticoagulation (n = 119), with high-risk trauma (n = 14), and for surgical prophylaxis (n = 16). When the patient was no longer at risk for pulmonary embolism as determined by clinical assessment, an attempt at filter conversion was made. Follow-up of converted patients (n = 93) was conducted at 30 days, 3 months, and 6 months after conversion. Patients who did not undergo a conversion attempt (n = 53) had follow-up at 6 months after implant. RESULTS: All implants were successful. One 7-day migration to the right atrium required surgical removal. Technical success rate for filter conversion was 92.7% (89/96). Mean time from placement to conversion was 130.7 days (range, 15-391 d). No major conversion-related events were reported. The mean conversion procedure time was 30.7 minutes (range, 7-135 min). There were 89 converted and 32 unconverted patients who completed 6-month follow-up with no delayed complications. CONCLUSIONS: The VenaTech Convertible filter has a high conversion rate and low 6-month device-related adverse event rate. Further studies are necessary to determine long-term safety and efficacy in both converted and unconverted patients.

Characterization of in vivo ablation zones following percutaneous microwave ablation of the liver with two commercially available devices: are manufacturer published reference values useful?

PURPOSE: To analyze in vivo ablation properties of microwave ablation antennae in tumor-bearing human livers by performing retrospective analysis of ablation zones following treatment with two microwave ablation systems. MATERIALS AND METHODS: Percutaneous microwave ablations performed in the liver between February 2011 and February 2013 with use of the AMICA and Certus PR ablation antennae were included. Immediate postablation computed tomography images were evaluated retrospectively for ablation length, diameter, and volume. Ablation length, diameter, and volume indices were calculated and compared between in vivo results and references provided from each device manufacturer. The two microwave antenna models were then also compared versus each other. RESULTS: Twenty-five ablations were performed in 20 patients with the AMICA antenna, and 11 ablations were performed in eight patients with the Certus PR antenna. The AMICA and Certus PR antennae showed significant differences in ablation length (P = .013 and P = .009), diameter (P = .001 and P = .009), and volume (P = .003 and P = .009). The AMICA ablation indices were significantly higher than the Certus PR ablation indices in length (P = .026) and volume (P = .002), but there was no significant difference in ablation diameter indices (P = .110). CONCLUSIONS: In vivo ablation indices of human tumors are significantly smaller than reference ex vivo ablation indices, and there are significant differences in ablation indices and sphericity between devices.

Open surgical inferior vena cava filter retrieval for caval perforation and a novel technique for minimal cavotomy filter extraction.

Late complications of retrievable inferior vena cava (IVC) filters resulting from IVC perforation and erosion into adjacent structures is an increasingly frequent phenomena. We describe six cases of open filter explantation for IVC penetration and offer a novel technique for open filter removal without the need for an extensive cavotomy. All patients had radiographic evidence of filter erosion into pericaval structures requiring open surgical filter explant. Four of the six patients underwent minimal cavatomy filter extraction, eliminating the need for caval reconstruction.

Transarterial Embolization for the Treatment of Chronic Musculoskeletal Pain: A Systematic Review of Indications, Safety, and Efficacy.

OBJECTIVE: The study objective was to evaluate the safety and efficacy of transcatheter arterial "embolization" (TAE) in the treatment of chronic "musculoskeletal pain" refractory to standard therapy. METHODS: PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were searched for original research articles evaluating TAE in patients with musculoskeletal conditions from database inception to January 21, 2020. Search terms employed were as follows: "embolization", "pain", "knee osteoarthritis", joint replacement, epicondylitis, tenderness, inflammation, WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index), microspheres, Embozene, geniculate artery, neovascularity, transcatheter, embolic, imipenem/cilastatin sodium, angiogenesis, and "musculoskeletal". Studies involving particle "embolization" for painful musculoskeletal conditions were included. Studies of TAE for hemarthrosis or malignancy-related "musculoskeletal pain" were excluded. RESULTS: The primary search yielded 1,099 sources; 7 articles and 4 abstracts were included for data extraction. All were cohorts or case series, with low risk of bias and moderate to poor level of evidence. Heterogeneity between studies was high, precluding meta-analysis. The reviewed studies reported the safety and efficacy of TAE for the treatment of "knee osteoarthritis"; adhesive capsulitis of the shoulder; tendinopathy/enthesopathy of the knee, shoulder, elbow, and ankle; and cervical myalgia. All TAEs were reported as technically successful without major complications or subsequent serious adverse events, including no reported osteonecrosis, cutaneous ulceration, limb ischemia, cartilage degeneration, or myotendinous injury. TAE significantly reduced pain and improved function for all of the treated conditions, with durable response up to 24 months post procedure. CONCLUSION: TAE appears to be a safe and effective treatment for some types of chronic refractory "musculoskeletal pain". Randomized placebo-controlled studies are necessary to confirm these findings.

Safety and Efficacy of Microwave Ablation for Hepatocellular Carcinoma in the Setting of Transjugular Intrahepatic Portosystemic Shunt.

This retrospective analysis reviews five patients with transjugular intrahepatic portosystemic shunt (TIPS) who underwent percutaneous microwave ablation of hepatocellular carcinoma between January 2017 and September 2020. Mean tumor diameter was 2.0 cm (range 1.3-2.9 cm), and mean tumor distance from TIPS was 2.3 cm (range 1.5-3.3 cm). There were no major adverse events, and the TIPS patency was 100% post-ablation. The technical success rate was 100%, and the complete response rate was 100%. In this small study, percutaneous microwave ablation appears safe and effective for the treatment of hepatocellular carcinoma in patients with TIPS in the short-term follow-up period.

Magnetic resonance angiography in the management of recurrent hemarthrosis after total knee arthroplasty.

Spontaneous hemarthrosis is an infrequent but disabling complication after total knee arthroplasty. The purpose of this case series is to demonstrate the utility of magnetic resonance angiography (MRA) in the evaluation of hemarthrosis after total knee arthroplasty. Patients presenting with hemarthrosis unexplained by trauma, anticoagulation, or a bleeding diathesis were retrospectively identified. Eighteen patients were referred for MRA to evaluate recurrent hemarthrosis after failing conservative therapy (n = 16) or synovectomy (n = 2). Despite artifact caused by the metallic components, diagnostic evaluation of regional vessels was made. In 12 of 13 cases that underwent embolization or synovectomy, a hypertrophic feeding artery (or arteries) was visualized on MRA. One case of negative MRA did not have subsequent surgery, and we are unable to comment on the rate of false-positives because all patients in this case series had evidence of bleeding. By characterizing the vascular anatomy and identifying a dominant artery (or arteries) supplying the hypervascular synovium, MRA can serve as a guide for subsequent embolization or synovectomy, as indicated.

Inferior Vena Cava Filters and Prevention of Recurrent Pulmonary Embolism.

Although inferior vena cava (IVC) filters have a clear role in preventing recurrent pulmonary embolism (PE) in patients with venous thromboembolism who cannot be anticoagulated, the role of filters in patients who are candidates for anticoagulation is controversial. With limited and conflicting data, practitioners often have to make an educated patient-specific decision when encountering this scenario. This article reviews the available data on the efficacy and risks associated with adjunctive IVC filter use to prevent recurrent PE.

Transjugular liver access cannula as a guiding instrument for the recanalization of chronic venous occlusions.

BACKGROUND: Chronic venous occlusions can result in debilitating symptoms and can be refractory to standard methods of venous recanalization because of the formation of dense fibrous tissue. A transjugular liver access cannula can be incorporated into recanalization efforts to treat such refractory cases. This report describes our experience using the transjugular liver access cannula technique in nine patients. METHODS: A review of patients requiring venous recanalization between May 2012 and October 2014 identified nine cases that required the use of a transjugular liver access cannula as a guiding instrument. Lesion characteristics, technical success, and clinical outcomes were evaluated. RESULTS: The transjugular liver access cannula was used to traverse a total of nine chronic occlusions in both the upper and lower central venous systems in nine patients. The technical success rate was 100%. There were no clinically significant complications. One patient was lost to follow-up. Of the remaining eight patients, seven experienced symptomatic relief within 1 month of recanalization. CONCLUSIONS: The transjugular liver access cannula may serve as a useful adjunctive tool during difficult venous recanalizations, especially when traditional guidewire and catheter techniques fail.

Inferior vena cava filter placement in orthopedic surgery.

Inferior vena cava (IVC) filters were developed for the treatment of venous thromboembolism but in high-risk patients are often used for prophylaxis instead. In the study reported here, we reviewed all the orthopedic surgery cases in which IVC filters were used at our institution in 2005. Charts were analyzed and patients contacted by telephone for long-term follow-up. IVC filters were used in 90 (0.96%) of the 9,348 inpatient orthopedic surgeries. Sixty-one percent of filters were placed for prophylaxis, though only 42% of patients with prophylactic filters had a contraindication to anticoagulation. Eighty-one percent of patients with prophylactic filters who received anticoagulation received warfarin. Ratios of prophylactic-to-treatment filters were 3.25 for fracture surgeries, 2.1 for arthroplasties, and 0.89 for spine surgeries. Five percent of patients with prophylactic filters developed deep vein thrombosis. Fifty-two percent of filters were retrievable, but only 40% of those were removed a mean of 5.1 months (SD, 3.9 months) after placement. Filter removal was associated with complications in 11% of patients, and in another 10% the filter could not be removed. Forty-one patients were contacted a mean of 21 months (SD, 3 months) after filter placement. Only 32% of those who still had filters were on anticoagulation at follow-up.

Color duplex sonography in severe transplant renal artery stenosis: a comparison of end-to-end and end-to-side arterial anastomoses.

OBJECTIVE: The aim of this study was to investigate differences in Doppler parameters between severe transplant renal artery stenosis (TRAS, arterial lumen reduction >80%) with end-to-end (EE) arterial anastomosis and that with end-to-side (ES) arterial anastomosis. METHODS: We retrospectively reviewed color duplex sonography (CDUS) and digital subtraction angiography (DSA) images in 38 patients with severe TRAS (19 cases with EE and 19 cases with ES) between January 1, 2000, and December 31, 2006. Doppler parameters were analyzed, including peak systolic velocity (PSV) in the iliac artery, PSV at the arterial anastomosis, PSV in the transplant renal artery, PSV ratio of the stenotic artery/artery proximal to the stenosis, and acceleration time (AT) in the artery distal to the stenosis (in the intrarenal artery). All 38 cases with severe TRAS were initially diagnosed with CDUS and confirmed by DSA. RESULTS: There were significant differences in PSV in the stenotic artery (P<.01), PSV in the iliac artery (P<.001), and PSV ratios of stenotic artery/artery proximal to the stenosis (P<.001) between arterial anastomosis of EE and that of ES. There was no statistically significant difference in AT in the intrarenal artery between the two types of anastomosis (P>.05). CONCLUSION: Significantly different PSVs in the stenotic artery, the iliac artery, and the PSV ratio between EE and ES arterial anastomoses should be considered in the interpretation of CDUS when screening for severe TRAS. Different criteria of CDUS need to be established depending on the type of arterial anastomosis in order to improve the accuracy in diagnosing severe TRAS.

Renal artery embolization: clinical indications and experience from over 100 cases.

OBJECTIVE: To review current indications and techniques for renal artery embolization (RAE) and more specifically to review cases of RAE before nephrectomy for treating patients with a large renal mass. PATIENTS AND METHODS: All RAEs done at our institution between May 1993 and December 2005 were reviewed. Patients were identified using a database assembled by the Division of Cardiovascular Interventional Radiology. Indications, techniques and RAE-related complications were then obtained from a retrospective review of medical records. Additional data for patients undergoing preoperative infarction were acquired, including estimated blood loss (EBL), transfusion requirement, pathological size, subtype, grade, stage, and level of tumour thrombus if present. RESULTS: In all, there were 121 RAEs, 69 in males and 52 in females (mean age 57.6 years, range 11-89). Metallic microcoils were the most often used embolization agent, followed by acrylic microspheres (embospheres), polyvinyl alcohol particles, absolute ethanol, and Gelfoam (Pharmacia & Upjohn, USA). The most common indication for RAE was infarction before nephrectomy (54.5%). Other indications included symptomatic angiomyolipomas, palliation of unresectable renal cancer, haemorrhage, perinephric bleeding in end-stage renal disease, vascular lesions, malignant hypertension, and sequelae of end-stage renal disease. RAE-associated complications including coil migration, incomplete embolization, and groin haematoma (in 5.0%). Symptoms of post-infarction syndrome were common, with 74.4% of patients having flank pain, nausea, or vomiting; the vast majority of these symptoms were mild and self-limited. In patients having nephrectomy after RAE the median (range) interval from RAE was 2 (0-78) days. The mean tumour size was 11.2 (3.5-25) cm and 46% of patients had tumour thrombus present in either the renal vein or inferior vena cava (IVC). The mean (median) overall EBL in patients having nephrectomy after RAE was 1048 (725) mL. The mean transfusion requirement over the course of hospitalization was 3.9 units of packed red blood cells. CONCLUSIONS: RAE is a safe and effective therapeutic tool for many urological, renal and vascular conditions. Its use has increased at our institution due to improved techniques, embolization materials, and our increasing use of RAE as an adjuvant procedure for patients requiring nephrectomy with or without IVC thrombectomy. There are many potential operative advantages for patients having RAE before surgery, with minimal morbidity. It is likely that the lack of prospective randomized trials is the primary reason why it is underutilized in the preoperative setting.

Quantitative evaluation of susceptibility and shielding effects of nitinol, platinum, cobalt-alloy, and stainless steel stents.

The purpose of this study is to quantitatively estimate the shielding and susceptibility effects of commonly used metallic stents on MR signal. Two experiments were performed using a 3D gradient echo sequence with short TE to image a stent phantom: 1) short TR and high flip angle (contrast enhanced MRA parameters), and 2) long TR (TR >> T(1)) and low flip angle. The factor characterizing susceptibility effects was estimated from the signal phase of the first experiment, and then the factor characterizing the shielding effects was derived from the second experiment. Susceptibility induced signal loss was negligible (<1%) for nonstainless-steel (nitinol, platinum, and cobalt-alloy) stents and totally destructive (100%) for the stainless steel stent. Signal loss due to RF shielding was 31-62% for nitinol stents, 14-50% for platinum stents, 50-77% for the cobalt-alloy stents (undetermined for the stainless steel stent), varied with stent orientation, diameter, and wall geometry. In summary, stents made of nitinol, platinum, and cobalt-alloy have negligible susceptibility effects but stents made of stainless steel may have complete dephasing. All stents have substantial shielding effects, which vary with composition, geometry, and orientation. Large platinum stents may have the smallest artifacts and are the best suited for postinterventional MR imaging.

Acute lower extremity ischemia in a 7-year-old boy: an unusual case of popliteal entrapment syndrome.

Popliteal artery entrapment syndrome is a rare cause of acute limb ischemia that most commonly is seen in young adults. The most significant complications associated with popliteal entrapment include aneurysm formation and acute thrombosis. This case presents the youngest patient ever reported with this syndrome and highlights the advantages of multimodal treatment including thrombolysis, popliteal aneurysm resection, and revascularization. Although a significant body of literature exists on popliteal entrapment syndrome in teenagers and young adults, it has not been reported previously in a patient younger than 11 years. Limb salvage was achieved in this patient with a combination of endovascular and surgical techniques.