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Purpose: Percutaneous revascularization is increasingly utilized to optimize linfrageniculate perfusion in patients with critical limb ischemia. Quantitation of arterial perfusion using conventional angiographic techniques is challenging in CLI patients. We evaluated the potential utility of a quantitative angiogra2Podiatric Surgery, University of Pennsylvania, Philadelphia, PA; phic software system to predict clinical success following revascularization. Materials and Methods: A prospective QA database identified a cohort of 78 patients with CLI managed by a multidisciplinary wound care team who underwent 159 arterial lower extremity revascularization procedures (including angioplasty, stenting, stent-grafting and atherectomy) over a 36 month period. Of these, a subset of 24 patients with critical limb ischemia (CLI) had DSA angiograms that were post-processed and analyzed for changes in infrageniculate perfusion using a quantitative software system (i-Flow, Siemens Medical Systems). Time to peak perfusion (TTP), mean slope of perfusion increase (MSP) and area under the perfusion curve (AUC) were compared before and after intervention. These changes were then correlated with clinical outcome. A composite endpoint of (a) improved Rutherford level, (b) healed wound within target angiosome, (c) improved wound perfusion at time of operative debridement and/or (d) reduction in planned amputation level was used to assign clinical outcome for each revascularization as success/failure. Results: Technical success was 100%; clinical success was 75% (18/24). Mean changes in TTP, MSP and AUC for the study cohort were -16%, 350% and 494%, respectively. Patients with clinical success had significantly greater AUC than failures (672% vs. -16%, P = 0.028); a trend toward greater MSP among patients with clinical success was also observed (449% vs. 84%, P = 0.09). No significant changes in time to peak perfusion were seen between patients with clinical success or failure. Conclusion: In this preliminary study, quantitative angiographic increases in infrageniculate blood flow measured through area under the perfusion curve was associated with clinical success following percutaneous revascularization. Further assessment of this technique is warranted in a larger, prospective cohort. [Copyright &y& Elsevier]

Purpose: In recent years, percutaneous cryoablation and radiofrequency ablation (RFA) have emerged as alternatives to surgery in the treatment of small renal masses (SRM). Although these techniques have shown promise, residual or recurrent tumor can be observed on follow-up imaging. The purpose of this study is to assess the natural history of residual tumor that is observed following thermal ablation procedures. Materials and Methods: With IRB approval, we retrospectively analyzed 166 renal tumors in 142 patients treated with either RFA or cryoablation. Subsequent imaging studies were reviewed to identify residual or recurrent viable tumor as demonstrated by contrast enhancement in the treatment area. The clinical, imaging, and therapeutic outcomes of the residual/recurrent renal tumor in patients who did not have repeat ablation of their residual tumor were evaluated. Results: Among the 166 ablated tumors, 18 (11%) demonstrated residual or recurrent contrast enhancement on MR or CT and were followed for a minimum of 12 months without intervention. At a mean radiological follow-up time of 35 months, 12 of the 18 patients (67%) under active surveillance demonstrated no tumor growth within the treatment bed while 6 patients (33%) had tumors that progressed. The average growth rate of the viable tumor in the progressing tumors was 165%/year. Except for two individuals with metastases prior to ablation, no patient, with an average follow-up time of 56 months, died of renal cell carcinoma. Conclusion: In cases where the patient is not amenable to further intervention due to renal insufficiency, significant comorbidities, residual tumor location or personal preference, active surveillance of post-ablation residual tumor may be an acceptable alternative. [Copyright &y& Elsevier]

Purpose: Bronchial artery embolization (BAE) is used to arrest hemoptysis in patients with inflammatory, infectious and neoplastic conditions. We compared rebleeding and mortality among patients undergoing BAE according to underlying pulmonary disease. Materials and Methods: A prospective QA database was used to identify a study cohort of 72 patients (45 males: 27 females) who underwent 100 consecutive BAE sessions at a tertiary academic medical center over 11 years. Patients each underwent 1 to 7 BAE sessions. 26 BAE were done in 13 patients with sarcoidosis (26% of BAE; 18% of patients). 74 BAE were done in 59 patients with other etiologies of hemoptysis, including cystic fibrosis (n=12), lung cancer (n=8), and bronchiectasis (n= 11). Rebleeding risk and survival was compared between sarcoid and non-sarcoid patients using the Kaplan-Meier technique. Results: Among the entire cohort, the percent of patients with recurrent hemoptysis requiring additional therapy (repeat BAE or bronchoscopy) at 1, 2 and 5 years was 39%, 47% and 51%, respectively. Median time to rebleeding following BAE was 29 days among sarcoid patients, compared to 293 days among non-sarcoid patients (P = 0.0013). Median survival following hemoptysis requiring BAE was 3.6 months among sarcoid patients; 78% of non-sarcoid patients were alive 5 years after BAE (P < 0.0001). The hazard ratio for death in sarcoid patients compared to other patients requiring BAE for hemoptysis was 4.0 (95% C.I. 2.6 - 14.6). Conclusion: Sarcoidosis patients are at significant risk for rebleeding and death following BAE compared to other lung diseases. [Copyright &y& Elsevier]

Purpose: Animal models have established a minimal ice ball margin of 0.3 cm for successful percutaneous cryoablation of small renal masses (SRM). This purpose of this study was to examine the CT characteristics of the intraprocedural ice ball during renal mass cryoablation and correlate this to post-cryoablation outcomes. Materials and Methods: This was a retrospective review of 63 consecutive patients undergoing percutaneous CT guided cryoablation at a single institution. The size and location of the renal mass and intraprocedural ice ball were recorded. The short axis ice ball diameter was compared to the renal mass diameter to determine the ice ball margin. Contrast enhanced MRI or CT scan performed 1 month after ablation classified the patient as a successful ablation (no enhancing tumor) or as having residual tumor (enhancing tumor). Results: A total of 50 patients (79%) had a successful ablation and 13 patients (21%) had residual tumor on follow-up imaging. The successfully treated patients had a mean lesion diameter of 2.5 cm (range: 0.9 - 4.3 cm), mean ice ball diameter of 3.6 cm (range: 1.7 - 5.2 cm), and mean ice ball margin of 0.4 cm (range: 0.2 - 1.2 cm). Masses with residual tumor had a mean diameter of 3.8 cm (range: 1.8 - 4.5 cm), mean ice ball diameter of 3.5 cm (range: 1.5 - 3.9 cm), and mean ice ball margin of -0.4 cm (range: -0.9 - 0.4 cm). Compared to the successful cases, residual tumors had larger lesion sizes (p < 0.01) and smaller ice ball margins (p < 0.01). There were no residual tumors when an ice ball margin of 0.5 cm or greater was achieved (100% sensitivity, 100% specificity). Outcome was independent of tumor location, hilar abutment, or number of cryoprobes. Conclusion: Ice ball margin can be helpful in predicting renal cryoablation outcome. Margins greater than 0.5 cm strongly correlated to successful treatment. Ice ball margins less than 0.5 cm and large lesion size correlated to residual tumor on follow-up imaging. Tumor location, hilar abutment, and number of cryoprobes did not affect outcome. [Copyright &y& Elsevier]

Purpose: Over 25% of prevalent U.S. hemodialysis patients receive renal replacement through catheters. Symmetrical tip dialysis catheters have become alternatives to split tip and step tip designs owing to low solute recirculation and ease of positioning. We compared flow characteristics and recirculation of two symmetrical tip dialysis catheters using computational flow dynamics (CFD). Materials and Methods: We compared the VectorFlow catheter (with helically contoured distal lumens which offset the vectors of blood entering and leaving the device) with the Palindrome catheter (with symmetrically cross-cut tips within a dual-D configuration). A previously validated CFD model was used to compare these catheters for recirculation (as percent blood flow), Platelet Activation State (PAS) (a computational metric of thrombogenicity) and Helical Flow Index (HFI, to quantify the helical content of the streaming blood) using a steady-state superior vena model assuming catheter flow rates of 400 mL/min. Results: Both catheters were associated with a recirculation close to zero. Arterial and venous lumen outflow Platelet Activation State (PAS) (70th percentile) of VectorFlow catheter vs. Palindrome was 1.88 x 10-6 vs. 2.09 x 10-6 (arterial); and 5.08 x 10-6 vs. 1.14 x 10-5 (venous), respectively. Both catheters exhibited a symmetrical venous flow structure away from the catheter tip and coherent helical trajectories entering the arterial lumen, but transitioning rapidly in the VectorFlow catheter to fully developed flow. HFI analysis showed that both the Palindrome and VectorFlow catheters exhibited helical flow, with HFI of 0.032 and 0.024, respectively; the helically contoured lumens of the VectorFlow were also effective in deflecting the venous flow away from the arterial lumen. Conclusion: Both VectorFlow and Palindrome catheters showed minimal recirculation rates compared to conventional step tip and split tip alternatives. The VectorFlow catheter was associated with lower Platelet Activation State (PAS) levels and helical deflection of blood from the venous lumen away from the arterial lumen. [Copyright &y& Elsevier]

Purpose: Percutaneous transluminal angioplasty (PTA) of stenosis within hemodialysis (HD) access circuits improves flow, but it is unknown whether central venous (CV) PTA ipsilateral to HD access does so. We sought to quantify the effect of CV PTA on intra-access blood flow in patients with symptomatic central venous stenosis (CVS). Materials and Methods: This IRB-approved prospective study enrolled 24 adults with face, neck, extremity, and/or breast edema ipsilateral to their HD access referred to IR for treatment. Five subjects were deregistered for various reasons (untreatable lesion, no CVS, or improper flow measurement timing); 19 completed the study (13M, 6F; mean age 59, range 33-83 years). There were 7 fistulas (2 basilic vein transposition, 5 nontransposed), 9 grafts, and 3 fistula/graft hybrids; 3 forearm, 14 upper arm, and 2 upper leg accesses. Mean access age was 732 (range 16-3039) days. Mean duration of CVS symptoms was 40 (range 3-120) days. Peripheral stenoses, if present, were treated first. Intra-access flow was measured (ReoCath, Transonic) immediately before and immediately after PTA of the CVS. Access characteristics, surgical history, and follow-up data were collected. Results: Eight patients had only CVS (subclavian, brachiocephalic, superior vena cava, infrarenal inferior vena cava, and/or common iliac), while 11 had at least one peripheral lesion in addition to their CVS. All stenoses underwent successful PTA. Mean flow was 1550 (range 565-2765) mL/min before CV PTA and 1625 (range 598-2545) mL/min after, giving a mean increase of 10% ±33% (95% confidence interval: -6% to +26%, p=0.52). CVS symptoms were reduced in 18 (95%) subjects but recurred in 6 (33%) within a mean of 94 (range 63-191) days after initial PTA. Mean follow-up was 159 (range 4-306) days. Conclusion: Despite significant short-term reduction in symptoms, mean intra-access blood flow improvement after successful CV PTA in patients with symptomatic CVS did not reach K/DOQI guidelines’ 20% threshold [1] for therapeutic interventions. Central venous PTA better corrects CVS symptoms than increases flow. [Copyright &y& Elsevier]