Diagnostic Accuracy of FDG PET for the Identification of Vascular Graft Infection.

BACKGROUND: Fluorodeoxyglucose (FDG) positron emission tomography (FDG PET/CT) can be used to identify and localize infection in patients with vascular graft infections (VGI). We aimed to evaluate the diagnostic accuracy of 18F-FDG PET/CT by defining thresholds for standardized uptake value (SUV) and tissue-to-background ratio (TBR) that would accurately identify the presence of vascular graft infection. METHODS: Patients with suspected VGI were prospectively recruited and underwent 18F-FDG PET/CT scans. Diagnosis was based on clinical, laboratory and radiologic findings, and blinded to the results of the PET/CT scan. Receiver operator characteristics (ROC) curve analysis was done to determine optimal thresholds for SUV and TBR. RESULTS: Our final cohort consisted of 28 patients with suspected VGI (mean ± SD age 67 ± 10 years, 61% men), of which 15 patients (54%) had definitive VGI. The cohort included 61% prosthetics grafts and 39% stent-grafts. The type of graft included in this study were biologic (4%), Dacron (64%) and Polytetrafluoroethylene (32%). The location of the implanted grafts was aortic (54%) and peripheral arterial reconstruction (46%). The location of the peripheral graft was 77% in lower extremity and 23% in the upper extremity (arterio-venous grafts for dialysis access). Using ROC analysis, SUV max of 4.5, SUV mean of 3.7, and a TBR of 1.6 gave the best balance between sensitivity and specificity (93%/92%, 100%/92% and 93%/92%, respectively). All thresholds had an area under the curve ≥0.93 and correct reclassification rate ≥93%. CONCLUSIONS: Our data suggests that FDG PET/CT can be used to reliably and accurately diagnose VGI. The dual anatomic-physiologic information from FDG PET/CT can complement clinical diagnosis particularly in uncertain cases.

Vasculink iPhone Application and Risk Prediction Model for Groin Complication in Vascular Surgery.

BACKGROUND: Postoperative groin complication is a common cause of morbidity in vascular surgery. Prophylactic wound adjuncts addressing this issue have been shown to reduce complications in high-risk patients, but their widespread implementation is limited by their high cost. This study introduces a risk prediction model for patients at a high risk for groin complication which can be accessed through the iPhone application, Vasculink. METHODS: A literature search identified risk prediction models for groin complication in vascular surgery. Odds ratios of risk factors that were present in at least 2 published models were calculated with a pooled effect size. The weighted risk for each factor was used to create our model and a cutoff point defining high risk patients was chosen. The initial model was assessed and validated using a split-sample methodology on a cohort identified via a retrospective chart review of all patients undergoing open vascular surgery at our institution between 2017 and 2020. Model performance was assessed using the C-statistic. RESULTS: Risk factors included in our model were female gender, body mass index ≥28 kg/m2, ever-smoker, reoperation, use of prosthetic, emergency, and end-stage renal disease. Of 216 patients, 131 were at a high risk. The overall groin complication rate was 43%, and specific complication rates were 27% infection, 14.8% seroma, and 6.9% hematoma. Our model's sensitivity and specificity were 92.47% and 60.98%, respectively. The C-statistic is 0.768. CONCLUSIONS: By using risk factors identified in the literature we have been able to establish a highly sensitive risk prediction model for groin complication following open vascular surgery. By incorporating our model into an iPhone application, Vasculink, we hope to facilitate preoperative decision making regarding the use of prophylactic wound adjuncts.

Managing an infected femoral artery pseudoaneurysm after thoraco-bifemoral bypass with an innovative configuration.

An infected femoral artery pseudoaneurysm after aortic reconstruction is a devastating surgical complication associated with the morbidity of limb loss and pelvic ischemia with a reinfection rate of ≤10%. In the present case report, we have described a unique approach for an infected femoral pseudoaneurysm after thoraco-bifemoral bypass using an innovative configuration, in addition to an obturator bypass technique, in a patient with a complex vascular history. This unique approach made use of an existing limb of a thoraco-bifemoral bypass graft to provide inflow to two outflow conduits, the external iliac artery and superficial femoral artery, allowing for preservation of both pelvic and lower extremity perfusion.

Printing Therapeutic Proteins in 3D using Nanoengineered Bioink to Control and Direct Cell Migration.

A nanoengineered bioink loaded with therapeutic proteins is designed to direct cell function in a 3D printed construct. The bioink is developed from a hydrolytically degradable polymer and 2D synthetic nanoparticle. The synthesis of poly(ethylene glycol)-dithiothreitol (PEGDTT) via a Michael-like step growth polymerization results in acrylate terminated degradable macromer. The addition of 2D nanosilicates to PEGDTT results in formation of shear-thinning bioinks with high printability and structural fidelity. The mechanical properties, swelling kinetics, and degradation rate of 3D printed constructs can be modulated by changing the ratio of PEG:PEGDTT and nanosilicates concentration. Due to high surface area and charged characteristic of nanosilicates, protein therapeutics can be sequestered in 3D printing structure for prolong duration. Sustained release of pro-angiogenic therapeutics from 3D printed structure, promoted rapid migration of human endothelial umbilical vein cell. This approach to design biologically active inks to control and direct cell behavior can be used to engineer 3D complex tissue structure for regenerative medicine.