Percent Thrombus Predicts Popliteal Artery Aneurysm Related Limb Threatening Events.

OBJECTIVE: The objective of this study was to identify clinical and anatomic characteristics of Popliteal artery aneurysms (PAAs) associated with acutely limb threatening events. SUMMARY BACKGROUND DATA: Popliteal artery aneurysms (PAAs) are associated with high morbidity and mortality. Current guidelines recommend operative repair for PAAs with a diameter greater than 20 mm based on very limited evidence. METHODS: This retrospective cross-sectional cohort was derived from a multi-institutional database queried for all patients with a PAA from 2008 to 2022. Duplex ultrasound (DUS) characteristics of PAAs were abstracted by registered physicians in vascular interpretation. Symptom status at the time of DUS was divided into three categories: asymptomatic PAA, symptomatic PAA with claudication or chronic limb ischemia, and acutely limb threatening PAAs with a thromboembolic event, acute limb ischemia, or rupture. RESULTS: There were 470 PAAs identified in 331 patients. The mean age was 74 years at diagnosis, 94% of patients were white, and 97% of patients were male. In a univariate analysis, patient comorbidities and medications were not associated with symptom status. In a multivariate analysis including age, higher percent thrombus was significantly associated with symptomatic PAAs (RRR 15.2; CI 2.69-72.3; P<0.01) and PAAs with an acutely limb threatening event (RRR 17.9; CI 3.76-85.0; P<0.01). All other anatomic characteristics were not associated with symptom status. CONCLUSION: Percent thrombus was significantly associated with symptomatic PAAs and acutely limb threatening events, whereas diameter was not significantly associated with any symptom group. This analysis supports the use of percent thrombus in identifying high risk PAAs that warrant repair.

Popliteal artery aneurysm ultrasound criteria for reporting characteristics.

INTRODUCTION: Duplex ultrasound (DUS) is the modality of choice for surveillance of popliteal artery aneurysms (PAAs). However, noninvasive vascular laboratories have no standard guidelines for reporting results. This study assessed reports of PAA DUS for inclusion of information pertinent to operative decision-making and timing of surveillance. METHODS: This study was a retrospective review of a multi-institutional repository that was queried for all patients with a PAA from 2008 to 2022 and confirmed via manual chart review. DUS reports were abstracted and images were individually annotated for features of interest including dimensions, flow abnormalities, and percent thrombus burden. RESULTS: A total of 166 PAAs in 130 patients had at least one DUS available for viewing. Postoperative surveillance of PAAs was performed at several intervals: the first at 30 months (IQR 3.7-113, n = 44), the second at 64 months (IQR 20-172, n = 31), and the third at 152 months (IQR 46-217, n = 16) after the operation. The largest diameter of operative PAAs (median 27.5 mm, IQR 21.8-38.0) was significantly greater than nonoperative PAAs (median 20.9 mm, IQR 16.7-27.3); p < 0.01. Fewer than 33 (21%) reports commented on patency of distal runoff. We calculated an average percent thrombus of 60% (IQR 19-81) in nonoperative PAAs, which is significantly smaller than 75% (IQR 58-89) in operative PAAs; p < 0.01. CONCLUSION: In this multi-institutional retrospective study, PAAs are often not followed at intervals recommended by the Society for Vascular Surgery guidelines and do not include all measurements necessary for clinical decision-making in the multi-institutional repository studied. There should be standardization of PAA DUS protocols performed by all noninvasive vascular laboratories to ensure completeness of PAA DUS images and inclusion of characteristics pertinent to clinical decision-making in radiology reports.

Routine Completion Angiography for Infrainguinal Bypasses Using Prosthetic Conduit: No Effect on Postoperative Patency.

BACKGROUND: Recent studies have demonstrated increased postoperative patency with the use of routine completion angiography for bypass using venous conduit. Compared to vein conduits, however, prosthetic conduits are less plagued by technical issues such as unlysed valves or arteriovenous fistulae. The effect of routine completion angiography on bypass patency in prosthetic bypasses has yet to be compared to the more traditional selective use of completion imaging. METHODS: A retrospective review of all infrainguinal bypass procedures using prosthetic conduit completed at a single hospital system from 2001 to 2018 was performed. Demographics, comorbidities, intraoperative reintervention rates, and 30-day rates of graft thrombosis were analyzed. Statistical analysis included t-tests, chi-square tests, and cox regression. RESULTS: Four hundred and ninety-eight bypasses that were performed in 426 patients met inclusion criteria. Fifty-six (11.2%) bypasses were classified into the routine completion angiogram group compared to 442 (88.8%) into the no completion angiogram group. Patients who underwent routine completion angiograms had a rate of intraoperative reintervention of 21.4%. When comparing bypasses that underwent routine completion angiography versus no completion angiography, there were no significant differences in rates of reintervention (3.5% vs. 4.5%, P = 0.74) or graft occlusion (3.5% vs. 4.7%, P = 0.69) at 30-days postoperatively. CONCLUSIONS: Almost one-quarter of lower extremity bypasses using prosthetic conduit that undergo routine completion angiography undergo postangiogram bypass revision; however, this is not associated with an increased graft patency at 30 days postoperatively.

Wall shear rate and energy loss coefficient measures using conventional Doppler ultrasound do not predict carotid plaque progression.

Background: The rate of carotid plaque progression is believed to be related to blood flow hemodynamics and shear stress. Our objective was to determine if wall shear rate (WSR) and the energy loss coefficient (ELC) measured by Doppler ultrasound could predict atherosclerotic carotid disease progression. Patients and methods: Patients at a large tertiary center with an initial ultrasound between 2016 and 2018 with a significant carotid plaque were included if they had at least one 6 months follow-up comparative study. Stenosis progression was assessed according to the NASCET (The North American Symptomatic Carotid Endarterectomy Trial) percentage criterion. Results: The average annual progression rate for the 74 plaques included was 5.7% NASCET per year. We identified 18 plaques with ≥10% NASCET progression and 56 plaques without significant progression <10% NASCET. Among the plaques with progression, only four plaques had progression greater than 20% NASCET. Median WSR was 6266 s-1 [5813-8974] in plaques with progression and 6564 s-1 [5285-8766] in stable plaques (p=0.643). Median ELC was 3.86 m2 [2.78-5.53] in plaque with progression and 4.32 m2 [3.42-6.81] in stable plaques (p=0.296). Conclusions: Although it is a widely accepted hypothesis that shear stress and hemodynamics of the carotid bifurcation contribute to plaque progression, we found that WSR and ELC estimated by Doppler ultrasound do not reliably predict atherosclerotic plaque progression in the carotid artery. Other ultrasound modalities, such as 3D imaging, may be used to assess the influence of plaque geometry and hemodynamics in plaque progression.

Corridor-diameter-dependent angular tolerance for safe transiliosacral screw placement: an anatomic study of 433 pelves.

BACKGROUND: The purpose of this study was to determine the angular tolerance of the S1 and S2 segments to accommodate a transiliosacral screw across both sacroiliac joints. HYPOTHESIS: We hypothesized that the angular tolerance for transiliosacral screw placement would be more constrained than the angular tolerance for iliosacral fixation in pelves where a safe osseous corridor was measured. MATERIALS AND METHODS: The cortical boundaries of the S1 and S2 sacral segments in 433 pelvic CTs were digitally mapped. A straight-line path was placed within each osseous corridor and extended across both SI joints past the outer iliac cortices. The diameter of the path was increased until it breached the cortex, geometrically determining maximum diameter (Dmax). Angular tolerance for screw placement was calculated with trigonometric analysis of the Dmax value of the corridor, and the average distance from the termination of the osseous corridor to the site of percutaneous insertion. Gender, age, and BMI were evaluated as independent predictors using binomial logistic regression. RESULTS: The transiliosacral angular tolerance for the S1 and S2 osseous corridors was 1.53 ± 0.57 degrees and 1.02 ± 0.33 degrees, respectively. 68.9% of S1 corridors and 81.1% of S2 corridors had a safe zone (corridor diameter ≥ 10 mm) for transiliosacral placement, 48.3% of the pelves had a safe zone for both corridors, while 5.1% had no safe zones. Females had a less frequent Dmax ≥ 10 mm at S1, 52% vs 67% (p = 0.001), and at S2, 64% vs 86% (p < 0.001). DISCUSSION: In conclusion, the angular tolerance of 1.53 and 1.03 degrees for the S1 and S2 segments, respectively, creating a narrow interval for safe passage of the trans-iliac and trans-sacral, with approximately 31.1% of patients not having a viable corridor for screw passage. A correlation exist between S1 and S2 corridors with Dmax ≥ 10 mm and the resulting increase in angular tolerance for safe passage of a transilioscral screw. LEVEL OF EVIDENCE IV: Level Retrospective Cohort.

Self-assembled liver organoids recapitulate hepatobiliary organogenesis in vitro.

Several three-dimensional cell culture systems are currently available to create liver organoids. In gneral, these systems display better physiologic and metabolic aspects of intact liver tissue compared with two-dimensional culture systems. However, none reliably mimic human liver development, including parallel formation of hepatocyte and cholangiocyte anatomical structures. Here, we show that human fetal liver progenitor cells self-assembled inside acellular liver extracellular matrix scaffolds to form three-dimensional liver organoids that recapitulated several aspects of hepatobiliary organogenesis and resulted in concomitant formation of progressively more differentiated hepatocytes and bile duct structures. The duct morphogenesis process was interrupted by inhibiting Notch signaling, in an attempt to create a liver developmental disease model with a similar phenotype to Alagille syndrome. Conclusion: In the current study, we created an in vitro model of human liver development and disease, physiology, and metabolism, supported by liver extracellular matrix substrata; we envision that it will be used in the future to study mechanisms of hepatic and biliary development and for disease modeling and drug screening. (Hepatology 2018;67:750-761).

The Application of Virtual Reality in Patient Education.

BACKGROUND: Virtual reality (VR) provides an immersive image-viewing experience that has recently been expanding in use in clinical medicine. We developed a three-dimensional (3D) model of an abdominal aortic aneurysm (AAA) for patients with a diagnosis of an AAA to view in VR to assess the use of VR in patient education. METHODS: This was a cross-sectional study using an educational intervention. A standardized 3D model of an AAA was generated from a computed tomography scan and uploaded onto a 3D image-hosting website. Patients with an AAA who participated in the study wore a Google Cardboard VR headset, with a mobile device displaying the digital 3D AAA image in VR. Patients completed a survey afterward for assessing satisfaction with VR on a 5-point agreement Likert scale. RESULTS: Between September 2017 and January 2018, 19 patients participated in our study (90% participation rate). Most participants had no prior experience with VR (n = 15; 79%), and the mean age was 69 ± 8 years. Seventeen (89%) participants agreed or strongly agreed that they felt better informed about their health status after using VR and would like to see VR used more in their health care, while sixteen (84%) agreed or strongly agreed that they felt more engaged in their health care because of using VR. Almost all participants felt comfortable using VR (n = 17; 90%) and enjoyed using the technology (n = 16; 84%). CONCLUSIONS: VR proved to be an engaging learning tool that patients perceived as beneficial in understanding their health status. Further efforts to investigate the role of VR in education and health care should be explored.

Pilot Study to Improve Resident Experience on Vascular Surgery by Standardizing Dissemination of Operative Steps.

OBJECTIVE: Many surgical residencies have passed along attendings preferences and procedural knowledge as a highly utilized but informal resource. The objective was to assess the effect of providing operative steps and attending preferences on surgical resident performance. DESIGN: This was a prospective observational study with a survey-based design. SETTING: We created and shared vascular surgery operative steps including institutional and attending preferences with junior residents at the Massachusetts General Hospital. PARTICIPANTS: There were a total of 31 residents who completed a survey to assess self-perception of performance in operative knowledge and Accreditation Council for Graduate Medical Education (ACGME) Milestone criteria. RESULTS: Advice from colleagues was the most utilized resource, followed by web-based materials. Of the web-based materials, almost all residents utilized Google searches over other web-based resources designed to specifically help surgical trainees. The vascular surgery resource was used by 90% of residents more than 3 times per week to prepare for operative cases. There was significant improvement in patient positioning, instrument selection, operative field exposure, anatomy, sequence of procedure, procedure choices, and peri-operative care knowledge. CONCLUSIONS: Development of institutional resources that specifically capture attending surgeon procedural variations can improve resident performance, encourage resident autonomy, and provide a catalog of approaches to challenging operative situations.

Magnetic Compression Anastomosis (Magnamosis) for Functional Undiversion of Ileostomy in Pediatric Patients.

INTRODUCTION: Magnamosis forms a compression anastomosis using self-aligning magnetic Harrison rings. The device has been approved by the Food and Drug Administration for first-in-human testing and has been applied in adults for intestinal anastomosis during urologic reconstructions. We now report the first cases of magnamosis to functionally undivert the fecal stream from a previously created loop ileostomy in pediatric patients. MATERIALS AND METHODS: Case 1: A 4-year-old male underwent a diverting loop ileostomy for malignant bowel obstruction. The obstruction gradually resolved with chemotherapy, and persistently high stomal output and malnutrition prompted undiversion. Case 2: A 16-year-old female with iloecolonic polyposis underwent ileoproctectomy with J pouch and diverting ileostomy. The magnamosis functional undiversion (FUN) technique involves introducing a Harrison ring through each stomal limb under general anesthesia with X-ray guidance. Magnets are each tied with sutures that exit the stoma and are then tied to each other externally. The device is removed when patency is detected. RESULTS: The introduction procedure took less than 20 minutes and there were no complications. Enteral feeding was initiated 24 and 6 hours postoperatively, and distal passage of stool occurred by the fourth and fifth days, respectively. Magnets were removed 14 and 15 days postoperatively, without evidence of leak. CONCLUSION: We conclude that the magnamosis undiversion procedure is a safe, minimally invasive way to gradually refunctionalize the excluded distal bowel after previous diverting ostomy.