Radiomics and machine learning for renal tumor subtype assessment using multiphase computed tomography in a multicenter setting.

OBJECTIVES: To distinguish histological subtypes of renal tumors using radiomic features and machine learning (ML) based on multiphase computed tomography (CT). MATERIAL AND METHODS: Patients who underwent surgical treatment for renal tumors at two tertiary centers from 2012 to 2022 were included retrospectively. Preoperative arterial (corticomedullary) and venous (nephrogenic) phase CT scans from these centers, as well as from external imaging facilities, were manually segmented, and standardized radiomic features were extracted. Following preprocessing and addressing the class imbalance, a ML algorithm based on extreme gradient boosting trees (XGB) was employed to predict renal tumor subtypes using 10-fold cross-validation. The evaluation was conducted using the multiclass area under the receiver operating characteristic curve (AUC). Algorithms were trained on data from one center and independently tested on data from the other center. RESULTS: The training cohort comprised n = 297 patients (64.3% clear cell renal cell cancer [RCC], 13.5% papillary renal cell carcinoma (pRCC), 7.4% chromophobe RCC, 9.4% oncocytomas, and 5.4% angiomyolipomas (AML)), and the testing cohort n = 121 patients (56.2%/16.5%/3.3%/21.5%/2.5%). The XGB algorithm demonstrated a diagnostic performance of AUC = 0.81/0.64/0.8 for venous/arterial/combined contrast phase CT in the training cohort, and AUC = 0.75/0.67/0.75 in the independent testing cohort. In pairwise comparisons, the lowest diagnostic accuracy was evident for the identification of oncocytomas (AUC = 0.57-0.69), and the highest for the identification of AMLs (AUC = 0.9-0.94) CONCLUSION: Radiomic feature analyses can distinguish renal tumor subtypes on routinely acquired CTs, with oncocytomas being the hardest subtype to identify. CLINICAL RELEVANCE STATEMENT: Radiomic feature analyses yield robust results for renal tumor assessment on routine CTs. Although radiologists routinely rely on arterial phase CT for renal tumor assessment and operative planning, radiomic features derived from arterial phase did not improve the accuracy of renal tumor subtype identification in our cohort.

The TOPOS study.

Background: We aimed to study the long-term safety and efficacy of oblique venous stents for post-thrombotic syndrome (PTS) with iliac vein compression. Patients and methods: In the multinational, prospective, single-arm TOPOS study, PTS patients scheduled for endovascular therapy with the sinus-Obliquus® stent and optional distal extension with the sinus-Venous® or sinus-XL Flex® stent were enrolled at eight European vascular centres between October 2016 and December 2020. The primary outcome was primary stent patency at 24 months, and secondary outcomes included the clinical course of PTS (Villalta score, revised Venous Clinical Severity Score [rVCSS], Visual Analog Scale [VAS] of pain), quality of life changes (Chronic Venous Insufficiency Quality of Life Questionnaire, CIVIQ-20), and device-related complications. Results: We enrolled 60 patients (mean age 46±15 years, 68% women, 13% active ulcers): 80% required stent extension (70% below the inguinal ligament). The primary patency rate at 24 months was 80.7% (95%CI 68.1-90.0%); it was higher in patients without vs. those with stent extension (90.9% vs. 78.3%, p=.01). Compared to baseline, the Villalta, rVCSS, pain VAS, and CIVIQ-20 decreased by a median of 8 (interquartile range (IQR): 4-11), 5 (IQR: 3-7), 3 (IQR: 2-5), and 17 (IQR: 6-22) points, respectively; p<.001 for all parameters. Overall, 9 events of acute stent occlusion, 4 symptomatic stent stenosis, and 1 pulmonary embolism occurred. We did not observe major bleeding events or contralateral thrombosis. Conclusions: Endovascular treatment with the oblique stent and optional stent extension was safe and resulted in high patency rates at 24 months. The reduction in PTS severity was substantial and persisted over 2-year follow-up.

Endovascular Rescue Aortic Fenestration After Accidental False Lumen TEVAR in Type B Dissection.

PURPOSE: Unintended false-lumen thoracic endovascular aortic repair (TEVAR) is under-reported and often fatal. We present percutaneous endovascular rescue techniques for true-lumen reperfusion with strategies to address the peripheral artery perfusion needs unique to each case. CASE REPORT: Two patients deteriorated 24 hours after uncomplicated and complicated acute aortic type-B dissection TEVAR treatment at a tertiary community hospital. Reevaluation of index and repeated imaging studies revealed inadvertent false-lumen TEVAR with severe visceral and peripheral ischemia. Stepwise subtraction angiography was used to confirm continuous true-lumen catheterization from femoral puncture into the thoracic aorta. Retrograde fenestration distal to the misplaced TEVAR from the true- into the false-lumen allowed for snorkeling by distal stent-extension across the dissection membrane. In one case, TEVAR stent graft extension resulted in true-lumen re-expansion and in the other case, bare-metal stent-extension for stabilization of the dissection membrane resulted in true-lumen re-expansion in addition to preservation of visceral and peripheral perfusion via the false-lumen. Despite excellent acute hemodynamic results and initial signs of recovery, both patients eventually died (multiorgan failure; cerebral hemorrhagic infarction). CONCLUSION: Correct indication and prompt recognition of potential inadvertent false-lumen stenting is critical to avoid disastrous sequelae, for example, malperfusion. Endovascular salvage is feasible for restoration of correct perfusion and must be performed in a timely manner. CLINICAL IMPACT: Clinically apparent, complicated type-B dissection necessitates instantaneous treatment. Prerequisite for an endovascular approach is a true-lumen guidewire continuously from access to the ascending aorta. DSA after TEVAR and prompt clinical re-evaluation are to verify effective visceral and peripheral restoration of blood flow. Despite these measures, inadvertent false-lumen TEVAR may occur rarely. Immediate recognition may allow for timely true-lumen re-expansion using percutaneous endovascular salvage techniques e.g. retrograde fenestration from the true- into the false-lumen for distal snorkeling of the misplaced TEVAR across the dissection membrane. However, morbidity and mortality are very high, if erroneous stent graft placement is not identified early.

Diagnostic Performance of a Lower-dose Contrast-Enhanced 4D Dynamic MR Angiography of the Lower Extremities at 3 T Using Multisegmental Time-Resolved Maximum Intensity Projections.

BACKGROUND: For peripheral artery disease (PAD), MR angiography (MRA) is a well-established diagnostic modality providing morphologic and dynamic information comparable to digital subtraction angiography (DSA). However, relatively large amounts of contrast agents are necessary to achieve this. PURPOSE: To evaluate the diagnostic accuracy of time-resolved 4D MR-angiography with interleaved stochastic trajectories (TWIST-MRA) by using maximum intensity projections (MIPs) of dynamic images acquired with reduced doses of contrast agent. STUDY TYPE: Retrospective. POPULATION: Forty adult PAD patients yielding 1088 artery segments. FIELD STRENGTH/SEQUENCE: A 3.0 T, time-resolved 4D MR-angiography with TWIST-MRA and MIP of dynamic images. ASSESSMENT: DSA was available in 14 patients (256 artery segments) and used as reference standard. Three-segmental MIP reconstructions of TWIST-images after administration of 3 mL of gadolinium-based contrast agent (Gadoteridol/Prohance®, 0.5 M) per anatomical level (pelvis, thighs, and lower legs) yielded 256 artery segments for correlation between MRA and DSA. Three independent observers rated image quality (scale: 1 [nondiagnostic] to 4 [excellent]) and the degree of venous overlay (scale: 0 [none] to 2 [significant]) for all segments. Diagnostic accuracy for the detection of >50% stenosis and artery occlusion was calculated for all observers. STATISTICAL TESTS: Binary classification test (sensitivity, specificity, positive/negative predictive values, diagnostic accuracy). Intraclass correlation coefficients (ICCs), logistic regression analysis with comparison of areas under the receiver-operating-characteristics (ROC) curves (AUCs) with the DeLong method. Bland-Altman-comparison. RESULTS: High diagnostic performance was achieved for the detection of >50% stenosis (sensitivity 92.9% [84.3-99.9% (95%-CI)] and specificity 98.5% [95.7-99.8% (95%-CI)]) and artery occlusion (sensitivity 93.1% [77.2-99.2% (95%-CI)] and specificity 99.1% [96.9-99.9% (95%-CI)]). Inter-reader agreement was excellent with ICC values ranging from 0.95 to 1.0 for >50% artery stenosis and occlusion. Image quality was good to excellent for both readers (3.41 ± 0.72, 3.33 ± 0.65, and 3.38 ± 0.61 [mean ± SD]) with good correlation between observer ratings (ICC 0.71-0.81). No significant venous overlay was observed (0.06 ± 0.24, 0.23 ± 0.43 and 0.11 ± 0.45 [mean ± SD]). DATA CONCLUSION: MIPs of dynamic TWIST-MRA offer a promising diagnostic alternative necessitating only reduced amounts (50%) of gadolinium-based contrast agents for the entire runoff vasculature. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

Volume-Function Analysis (LiMAx Test) in Patients with HCC and Cirrhosis Undergoing TACE-A Feasibility Study.

BACKGROUND: Transarterial chemoembolization (TACE) is an important therapy for hepatocellular carcinoma (HCC) in cirrhosis. In particular in advanced cirrhosis, post-TACE hepatic failure liver (PTHF) failure may develop. Currently, there is no standardization for the periinterventional risk assessment. The liver maximum capacity (LiMAx) test assesses the functional liver capacity, but has not been investigated in this setting. AIMS: The aim of this study was to prospectively evaluate periinterventional LiMAx and CT volumetry measurements in patients with cirrhosis and HCC undergoing repetitive TACE. METHODS: From 06/2016 to 11/2017, eleven patients with HCC and cirrhosis undergoing TACE were included. LiMAx measurements (n = 42) were conducted before and after each TACE. Laboratory parameters were correlated with the volume-function data. RESULTS: The median LiMAx levels before (276 ± 166 µg/kg/h) were slightly reduced after TACE (251 ± 122 µg/kg/h; p = 0.08). This corresponded to a median drop of 7.1%. Notably, there was a significant correlation between LiMAx levels before TACE and bilirubin (but not albumin nor albumin-bilirubin [ALBI] score) increase after TACE (p = 0.02, k = 0.56). Furthermore, a significantly higher increase in bilirubin in patients with LiMAx ≤ 150 µg/kg/h was observed (p = 0.011). LiMAx levels at different time points in single patients were similar (p = 0.2). CONCLUSION: In our prospective pilot study in patients with HCC and cirrhosis undergoing multiple TACE, robust and reliable LiMAx measurements were demonstrated. Lower LiMAx levels before TACE were associated with surrogate markers (bilirubin) of liver failure after TACE. Specific subgroups at high risk of PTHF should be investigated. This might facilitate the future development of strategies to prevent occurrence of PTHF.

Predictive Power of Liver Maximum Function Capacity Test in Transjugular Intrahepatic Portosystemic Shunt Patients: A Pilot Study.

BACKGROUND: Transjugular intrahepatic shunt (TIPSS) is placed in patients with variceal bleeding, refractory ascites, and for other indications. Postprocedural liver function-associated complications (LFAC), including hepatic encephalopathy (HE) and liver failure, represent a major setback. Current methods to predict complications are insufficient. OBJECTIVES: We investigated in a pilot study of patients prior TIPSS placement whether the risk of LFAC correlates with the functional reserve of the liver, as assessed by liver maximum function capacity (LiMAx) test. METHODS: Prospectively we included patients prior TIPSS placement between June 2016 and November 2017 at Saarland University Medical Center. LiMAx was conducted before and after TIPSS placement. Patients with HE prior TIPSS, as well as other factors predisposing to HE, including concomitant sedative drugs, current bacterial infections and sepsis, were excluded. Overt HE (OHE), LiMAx, and laboratory values were assessed before and after TIPSS placement. Data were analyzed in multivariate regression and AUROC models. RESULTS: Mean age was 60 ± 8 years. Patients (n = 20) were mainly men (65%), and presented predominantly with Child-Pugh class B (90%). Indications for TIPSS were most commonly refractory ascites or recurrent variceal bleeding. In total, 40% of the patients developed LFAC after TIPSS placement. Expectedly, LiMAx decreased and serum bilirubin increased after TIPSS. LiMAx drop ≥20% was the only parameter predicting the development of LFAC after TIPSS in multivariate regression and AUROC analysis. CONCLUSIONS: In multivariate regression models and AUROC analysis, a drop in LiMAx predicted the development of LFAC after TIPSS placement. Additional larger studies assessing OHE and early liver failure separately are warranted.

Early clinical outcomes for treatment of post-thrombotic syndrome and common iliac vein compression with a hybrid Oblique self-expanding nitinol stent - the TOPOS study.

Background: Physical attributes of conventional stents used in the ilio-caval territory are often unfavorable in the presence of external compression close to the bifurcation. A hybrid oblique stent was developed for the treatment of common iliac vein compression without compromising the contralateral iliac vein inflow. Patients and methods: The ongoing international monitored TOPOS study enrolled 60 patients with post-thrombotic syndrome (PTS) treated with the sinus-Obliquus stent (optimed) and provisional distal stent extension. At 3-month follow-up, patency rates were obtained from duplex ultrasound, and clinical outcomes were assessed by the Villalta score, revised venous severity score (rVCSS), pain intensity score and chronic venous disease quality of life questionnaire (CIVIQ-20). Results: Mean age was 46.6 ± 14.9 years (68.3 % women). Mean number of implanted stents was 1.9 ± 0.6; 12 (20 %) patients received the hybrid oblique stent only. Forty-eight (80 %) patients had distal stent extension, and 42 (70 %) had stents below the inguinal ligament. Four (7 %) patients (all with stent extension) developed stent thrombosis. Primary and secondary patency rates at 3 months were 93.1 % (95 %CI 83.3-98.1 %), and 100 % (95 %CI 93.8-100 %), respectively. Improvement in Villalta, rVCSS, CIVIQ-20, and pain intensity score from baseline to 3-month follow-up was 6.9 ± 1.4 points (95 %CI 4.1-9.8; p < 0.0001), 3.4 ± 1.0 points (95 %CI 1.3-5.4 points; p < 0.01), 13.6 ± 2.7 points (95 %CI 8.2-19.0 points; p < 0.0001), and 2.4 ± 0.5 (95 %CI 1.4-3.3; p < 0.0001), respectively. At follow-up, 38 (63 %) patients were free from the PTS and none developed contralateral deep vein thrombosis. Conclusions: In patients with PTS and common iliac vein compression, treatment with the hybrid oblique stent with provisional stent extension resulted in high patency rates and improvement in PTS severity and quality of life at 3-month. Two-year results of TOPOS will assess the durability of this treatment.

Percutaneous endovascular tissue sampling of endoluminal tumors using directional atherectomy.

OBJECTIVES: To evaluate technical feasibility and safety of endovascular tumor specimen sampling using an escalating endovascular biopsy strategy using a directional atherectomy device compared with forceps biopsy and catheter aspiration. MATERIALS AND METHODS: Between 2013 and 2017, a cohort of ten consecutive patients (6 male; median age 56, range 39-73 years) was referred for sampling of endovascular masses. Localizations included the abdominal aorta (n = 4), left brachiocephalic vein (n = 2), inferior vena cava (n = 1), and left pulmonary artery (n = 3). For each individual mass, all three endovascular tissue sampling approaches were applied including catheter-based aspiration, straight two-jaw biopsy forceps, and directional atherectomy during a single session. RESULTS: Aspiration and forceps biopsy did not provide sufficient material for histological analyses. In contrast, technical success for endovascular tumor sampling using directional atherectomy was 100%. After two atherectomy passages, sufficient material was available for each vessel region allowing histologic diagnosis, which revealed sarcoma and chronic inflammation for masses in the aorta, angiosarcoma for brachiocephalic vein, hepatocellular carcinoma for inferior vena cava, and angiosarcoma for pulmonary artery. In case of a histologically benign diagnosis, no malignant tumor proliferation was obvious on follow-up imaging studies after 3 months and 1 year. Thus, the rate of false-negative results was considered 0%. No procedure-associated complications, e.g., vessel perforation, were recorded. CONCLUSION: Preliminary results in a limited number of patients proved directional atherectomy beneficial as a safe and feasible technique for endoluminal tissue sampling of vascular masses. Additional large-scale studies are necessary and worthy for further evaluation in clinical practice. KEY POINTS: • Endovascular masses pose a challenge to appropriate clinical management. • Off-label directional atherectomy proved to be a safe and feasible technique for endoluminal tissue sampling of vascular masses. Furthermore, directional atherectomy was superior to aspiration or forceps biopsy in our small study cohort. • Directional atherectomy may represent the last or only option for tissue probing as a prerequisite for further treatment decisions.

Glass-Fiber-based MR-safe Guidewire for MR Imaging-guided Endovascular Interventions: In Vitro and Preclinical in Vivo Feasibility Study.

Purpose To evaluate glass-fiber-based guidewires that are safe for magnetic resonance (MR) imaging-guided endovascular interventions by using a phantom and an in vivo swine model. Materials and Methods MR imaging-safe guidewires were made from micropultruded glass and/or aramid fibers and epoxy resin with diameters of 0.89 mm (0.035 inch) for standard and stiff guidewires and 0.36 mm (0.014 inch) for micro guidewires. MR imaging visibility and mechanical properties were assessed in a pulsatile flow model. After approval was obtained from the institutional animal care and use committee, MR imaging guidewires were evaluated for standard endovascular procedures in nine pigs. Real-time steady-state free-precession sequences were used for MR imaging-guided catheterization, balloon dilation, and stent implantation into aorto-iliac/visceral arteries and the vena cava (temporal resolution, five images per second; and spatial resolution, 150-mm field of view, and 128 × 128 matrix) with a 1.5-T clinical imager. Visualization with the guidewires was rated on a four-point scale, handling was rated on a three-point scale, and catheterization times for different vessel regions were determined by two interventional radiologists. Afterward, handling ratings and catheterization times were obtained for standard nitinol guidewires during x-ray-based fluoroscopy. Cannulation times, signal intensity in each vessel region, and visualization and handling ratings were measured for the MR imaging guidewires. Bland-Altman analysis was performed for inter- and intraobserver variability of cannulation time. Spearman rank correlation was used to compare handling of MR imaging guidewires and standard nitinol guidewires. Results MR imaging guidewires were characterized by good to excellent visibility, with a continuous artifact of 2 mm in diameter and 4 × 8-mm ball-shaped tip marker. Stiffness, flexibility, and guidance reflected comparable times for all in vitro and in vivo procedures with both the MR imaging and standard nitinol guidewires. Standard and micro MR imaging guidewires were most suitable for the iliac crossover maneuver. Phantom visceral artery cannulation was easier with standard and micro MR imaging guidewires. The stiff MR imaging guidewire provided the best support for cannulation of the swine aorta and vena cava. All interventional procedures were performed successfully without complications. Conclusion Preliminary results showed that the use of glass-fiber-based guidewires for evaluation of MR imaging-guided endovascular interventions is technically feasible and safe in a swine model, and potentially, in humans. © RSNA, 2017 Online supplemental material is available for this article.

Local low-dose thrombolysis for safe and effective treatment of venous port-catheter thrombosis.

PURPOSE: Retrospective evaluation of local low-dose thrombolysis for treatment of venous port-catheter thrombosis. METHODS: A total of 1,031 patients with dysfunctional port systems underwent port angiography depicting 181 patients with thrombosis around the port-catheter. A total of 165 patients (male 35, female 130; age 57.3 ± 12.9 [20-83] years) underwent thrombolysis by single injection of 3 mg alteplase into the port system. Patients were followed up by clinical and angiographic/radiological port controls the next day and 12.9 ± 17.9 [1-81] months on the basis of regular oncologic staging examinations. RESULTS: Thrombosis occurred 10.1 ± 19.3 [median 2.9] months after port implantation and was clinically suspected by difficult blood aspiration in 146 of 181 (80.7 %) and high resistance to injection fluids in 75 (41.4 %) patients. A predictor for angiographically confirmed port-catheter thrombosis was a combination of both (73, 40.3 % patients) (Fisher's exact test p < 0.0001; positive predictive value 0.8977), or suboptimal (not cavoatrial) port-catheter position (92, 50.8 % patients) (p = 0.0047; positive predictive value 0.8276). The cumulative success rate of thrombolysis was 92.7 % (153 of 165 patients). Initial thrombolysis was effective in 127 (77.0 %) patients. Repeated (up to 6 times) thrombolysis was effective in 26 of 31 patients after second or third thrombolysis. Extensive central venous thrombosis (9 patients) predicted ineffective thrombolysis (p < 0.0001). Primary patency of successfully treated devices was 92.8 % at 1 month and 84.9 % at 3 months. Rethrombosis occurred in 27 patients after 4.4 ± 6.6 (median 1.8) months. Primary rethrombolysis was effective in 22 (81.5 %) patients. Cumulative patency was 100 % at 3 months. CONCLUSIONS: Difficult aspiration combined with high resistance to injection fluids or suboptimal port-catheter position are strong independent predictors for port-catheter thrombosis. Local low-dose thrombolysis or repeat thrombolysis is safe and effective in the absence of large central venous thrombosis.

Percutaneous Re-positioning of Dislocated Port-Catheters in Patients with Dysfunctional Central-Vein Port-Systems.

PURPOSE: Observational analysis of percutaneous repositioning of displaced port-catheters in patients with dysfunctional central-venous port-systems. METHODS: A total of 1061 patients with dysfunctional venous pectoral port-systems were referred for port-angiography. Dislocated port-catheters were identified in 37 (3.5 %) patients (11 males, mean age 58.1 ± 7.2 [range 48-69] years; 26 females, 57.0 ± 13.5 [range 24-75] years) 3.9 ± 6.6 months (range 1 day-26 months) after port-implantation. Percutaneous repositioning in all patients was performed by transfemoral catheter maneuvers, snaring, or wire-assisted long-loop snaring. Primary endpoint was successful repositioning. Safety endpoints included port-damage or procedure-related complications. Follow-up encompassed routine clinical and radiological controls, including chest X-ray or computed tomography for 12.9 ± 17.9 (range 1-81) months. RESULTS: Clinical signs of port-dysfunction due to dislocation of port-catheters included difficult aspiration in 23 (62.2 %), resistance or inability to inject in 17 (46.0 %), and pain during injection in 2 (5.4 %) patients. Primary technical success for repositioning displaced port-catheters was 97.3 % (36/37 patients). In 1 (2.7 %) patient, repositioning failed due to complete embedding of the port-catheter in an extensive chronic jugular vein thrombosis (Paget-von-Schroetter syndrome) that prevented endovascular access to the port-catheter. Redisplacement occurred after initial successful repositioning: immediately in two patients due to a too short port-catheter (two-tailed Fisher's exact-test, p = 0.0101), and in two patients with appropriate catheter-length after 5, resp. 7 months. No procedure-associated complications, e.g., port-catheter disconnection or disruption, occurred. CONCLUSIONS: Repositioning of dysfunctional displaced central-venous port-catheters with appropriate catheter-length is safe and effective. Even challenging conditions, e.g., wall-adherent port-catheter tip or a thrombosed catheter-bearing vein are feasible. Repositioning of too short port-catheters is ineffective.

Paclitaxel-coated balloon angioplasty for symptomatic central vein restenosis in patients with hemodialysis fistulas.

PURPOSE: To report a retrospective observational analysis of standard balloon angioplasty (BA) vs. paclitaxel-coated balloon angioplasty (PCBA) for symptomatic central vein restenoses in patients with impaired native hemodialysis fistulas. METHODS: A retrospective review was conducted of 27 consecutive patients (15 men; mean age 66 ± 13.8 years, range 39-90) with 32 central vein stenoses (CVS; 6 axillary, 11 subclavian, 12 brachiocephalic, and/or 3 superior caval veins) treated successfully using BA. Freedom from reintervention after BA of de novo lesions was 7.4 ± 7.9 months (range 1-24). Twenty-five (92.6%) patients developed symptomatic restenoses and were treated one or more times by BA (n = 32) or PCBA (n = 20) using custom-made paclitaxel-coated balloons (diameter 6-14 mm). RESULTS: Technical (< 30% residual stenosis) and clinical (functional fistula) success rates for the initial and secondary angioplasty procedures were 100%. No minor/major procedure-associated complications occurred. Mean follow-up was 18.4 ± 17.5 months. Kaplan-Meier analysis for freedom from target lesion revascularization (TLR) found PCBA superior to BA (p = 0.029). Median freedom from TLR after BA was 5 months; after PCBA, > 50% of patients were event-free during the observation period (mean freedom from TLR 10 months). Restenosis intervals were prolonged by PCBA (median 9 months) vs. BA (median 4 months; p = 0.023). CONCLUSION: Paclitaxel-coated balloon angioplasty of central vein restenosis in patients with hemodialysis shunts yields a statistically significant longer freedom from TLR compared to standard balloon angioplasty.

Transarterial chemoembolization (TACE) for colorectal liver metastases--current status and critical review.

BACKGROUND: Transarterial liver-directed therapies are currently not recommended as a standard treatment for colorectal liver metastases. Transarterial chemoembolization (TACE), however, is increasingly used for patients with liver-dominant colorectal metastases after failure of surgery or systemic chemotherapy. The limited available data potentially reveals TACE as a valuable option for pre- and post-operative downsizing, minimizing time-to-surgery, and prolongation of overall survival after surgery in patients with colorectal liver only metastases. PURPOSE: In this overview, the current status of TACE for the treatment of liver-dominant colorectal liver metastases is presented. Critical comments on its rationale, technical success, complications, toxicity, and side effects as well as oncologic outcomes are discussed. The role of TACE as a valuable adjunct to surgery is addressed regarding pre- and post-operative downsizing, conversion to resectability as well as improvement of the recurrence rate after potentially curative liver resection. Additionally, the concept of TACE for liver-dominant metastatic disease with a focus on new embolization technologies is outlined. CONCLUSIONS: There is encouraging data with regard to technical success, safety, and oncologic efficacy of TACE for colorectal liver metastases. The majority of studies are non-randomized single-center series mostly after failure of systemic therapies in the 2nd line and beyond. Emerging techniques including embolization with calibrated microspheres, with or without additional cytotoxic drugs, degradable starch microspheres, and technical innovations, e.g., cone-beam computed tomography (CT) allow a new highly standardized TACE procedure. The real efficacy of TACE for colorectal liver metastases in a neoadjuvant, adjuvant, and palliative setting has now to be evaluated in prospective randomized controlled trials.

Machine learning assisted feature identification and prediction of hemodynamic endpoints using computed tomography in patients with CTEPH.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but potentially curable cause of pulmonary hypertension (PH). Currently PH is diagnosed by right heart catheterisation. Computed tomography (CT) is used for ruling out other causes and operative planning. This study aims to evaluate importance of different quantitative/qualitative imaging features and develop a supervised machine learning (ML) model to predict hemodynamic risk groups. 127 Patients with diagnosed CTEPH who received preoperative right heart catheterization and thoracic CTA examinations (39 ECG-gated; 88 non-ECG gated) were included. 19 qualitative/quantitative imaging features and 3 hemodynamic parameters [mean pulmonary artery pressure, right atrial pressure (RAP), pulmonary artery oxygen saturation (PA SaO2)] were gathered. Diameter-based CT features were measured in axial and adjusted multiplane reconstructions (MPR). Univariate analysis was performed for qualitative and quantitative features. A random forest algorithm was trained on imaging features to predict hemodynamic risk groups. Feature importance was calculated for all models. Qualitative and quantitative parameters showed no significant differences between ECG and non-ECG gated CTs. Depending on reconstruction plane, five quantitative features were significantly different, but mean absolute difference between parameters (MPR vs. axial) was 0.3 mm with no difference in correlation with hemodynamic parameters. Univariate analysis showed moderate to strong correlation for multiple imaging features with hemodynamic parameters. The model achieved an AUC score of 0.82 for the mPAP based risk stratification and 0.74 for the PA SaO2 risk stratification. Contrast agent retention in hepatic vein, mosaic attenuation pattern and the ratio right atrium/left ventricle were the most important features among other parameters. Quantitative and qualitative imaging features of reconstructions correlate with hemodynamic parameters in preoperative CTEPH patients-regardless of MPR adaption. Machine learning based analysis of preoperative imaging features can be used for non-invasive risk stratification. Qualitative features seem to be more important than previously anticipated.

Successful management of postoperative necrotizing pancreatitis after infrarenal abdominal aortic aneurysm repair.

We present a case of severe necrotizing pancreatitis that developed after elective repair of an abdominal aortic aneurysm. Surgeons are confronted in cases of postoperative acute pancreatitis with the dilemma of potential intraabdominal infection and the high risk of a subsequent infection of the retroperitoneal synthetic material. The therapeutic options range from a restrictive regime to radical necrosectomy and multivisceral resection.

[Acute interventions-dialysis shunt recanalization]. / Akute Interventionen ­ Rekanalisation von Dialyseshunts.

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.

Feasibility of aortic aneurysm sac embolization using a novel shape memory polymer embolic device.

BACKGROUND: We investigated the feasibility of aneurysm sac embolization using a novel self-expanding porous shape memory polymer (SMP) device during endovascular aortic abdominal or thoracic aneurysm repair (EVAR). METHODS: Retrospective analysis of consecutive patients treated at 2 centers in Germany. Patients were treated from January 2019 to July 2021 with follow-up at 7 days and 3, 6, and 12 months. Aneurysm sacs were implanted with SMP devices immediately following endograft placement during the same procedure. Primary endpoint was technically successful SMP-device deployment into the aneurysm sac outside the endograft. Secondary endpoints were changes in aneurysm volume and associated complications (e.g., endoleaks). RESULTS: We included 18 patients (16 males), aged 72 ± 9 years, achieving 100% technical success. Mean preprocedure aortic aneurysm sac volume was 195 ± 117 mL with a perfused aneurysm volume of 97 ± 60 mL. A mean of 24 ± 12 SMP devices per patient were used (range 5-45, corresponding to 6.25-56.25 mL expanded embolic material volume). All evaluable patients exhibited sac regression except 2 patients yet to reach 3-month follow-up. At mean 11 ± 7 months (range 3-24), change in aneurysm volume from baseline was -30 ± 21 mL (p < 0.001). In 8 patients, aneurysm regression was observed despite type 2 endoleaks in 6 and type 1A endoleaks in 2, none of them requiring further intervention to date. No morbidity or mortality related to this treatment occurred. CONCLUSIONS: SMP devices for aortic aneurysm sac embolization during endovascular repair appear feasible and safe in this small case series. Prospective studies are needed. KEY POINTS: • Shape memory polymer is a novel, self-expanding, porous, and radiolucent embolic device material. • Aortic aneurysm sacs were treated with polymer devices immediately following endograft placement. • Aortic aneurysm sac regression was observed in all patients with over 3-month follow-up. • Aortic aneurysm sac regression was observed even in the presence of endoleaks.