The Role of Antigranulocyte Scintigraphy in Diagnosis of Aortic Graft Infection and Evaluation of Treatment Outcome.

BACKGROUND: The aim of this study was to assess the eventual added benefit of antigranulocyte monoclonal antibodies scintigraphy for the diagnostic imaging of aortic graft infection (AGI) and its role in evaluation of treatment outcome. METHODS: A population-based, retrospective, register-based analysis was carried out of all patients with infected aortic grafts after treatment for aneurysmal or aortoiliac occlusive disease at Karolinska University Hospital, covering the greater Stockholm area during November 2012-December 2020. Cases were based on the definitions in the 2016 Management of Aortic Graft Infection Collaborations consensus. Using the in-hospital electronic patient registry (Take Care®) and the Swedish National Registry for Vascular Surgery (Swedvasc), 835 patients who had been treated for aortic aneurysms or aortoiliac occlusive disease were identified. The diagnostic arsenal of laboratory tests, computed tomography (CT), and clinical signs has been supplemented by antigranulocyte monoclonal antibodies (anti-G mAb) scintigraphy. Data were analyzed using SPSS Statistics. RESULTS: Eighteen cases of AGI out of 835 operations incorporating aortic grafts during the period were identified. Fourteen patients (78%) were categorized as diagnosed AGI (AGI-D), and the remaining 4 (22%) were classified as suspected AGI (AGI-S). In the AGI-D group (n = 14), 10 patients (71%) had positive CTs and 4 (29%) had low-probability CTs. In the group of 10 positive CTs, 9 patients also had positive scintigraphy scans with only one negative scintigraphy scan. There were no negative scintigraphy scans without ongoing antibiotic treatment at the time of investigation. In 15 of 18 cases, a culprit agent was identified, either preoperatively or perioperatively. Thirteen of the 18 patients were treated solely by antibiotics, whereas 5 underwent surgical treatment in addition to antibiotic treatment. The outcome has been divided into 3 groups: infection-free (n = 6; 33%), lifelong antibiotic treatment (n = 7; 39%), and deceased (n = 5; 28%). CONCLUSIONS: The imaging modalities in AGI diagnostics are a cornerstone of the investigative work-up, complemented by clinical signs and laboratory methods. The main advantage conveyed by anti-G mAb scintigraphy is in postoperative imaging and its ability to differentiate between infection and general postoperative changes in the areas of concern. We have identified 6 patients in our cohort in whom antibiotic therapy was discontinued after a negative anti-G mAb scintigraphy scan. Anti-G mAb scintigraphy may fulfill a unique need for diagnosis in suspected cases, evaluation of therapeutic efficacy in patients requiring long-term antibiotic treatment, and aiding in the decision to discontinue antibiotic therapy.

Aortic Graft Infections after Emergency and Non-Emergency Reconstruction: Incidence, Treatment, and Long-Term Outcome.

BACKGROUND: Aortic graft infections (AGI) are rare, with an incidence of 0.6%-3% among patients with aortic grafts. Most previous reports are based on single-center material with limited follow-up. Because of the paucity of these cases, the optimal treatment remains unclear. A factor possibly affecting the mortality rate of these infections is whether the index procedure was emergency or elective. The aim of this study was to investigate the incidence of AGI and assess the long-term outcome after emergency and non-emergency aortic reconstruction in a large population. METHOD: A population-based, retrospective study was conducted of all patients treated with aortic reconstructive surgery at the two centers for vascular surgery in Stockholm County (population 2.2 million) during 2005-2015. Patients with AGI were identified by the in-hospital patient registry. Chart data on demographics, co-morbidity, index operation, type of infection, treatment, and outcome were analyzed. RESULTS: Reconstructive aortic surgery was performed on 2,026 patients (open repair 47.7%; endovascular aortic repair 52.3%). The incidence of infection was 1.4% (29/2,026). The index operation was performed as an emergency in ten patients and non-emergency in 19. Median follow-up after the index operation was 69.2 months (interquartile range [IQR] 109.5). Patients having an emergency index procedure were older (77 vs. 69 y; p = 0.03). Time to infection was similar (30.2 ± 27.4 and 56.1 ± 51.2 mos; p = 0.21). The median time from diagnosis of AGI to surgery was 30 d (IQR 30.5 d). Infectious agents were identified in 76% of the cases. Of the conservatively treated patients, one was free of infection compared with three of the surgically treated. Conservatively treated patients had a higher graft-associated mortality rate of 57% compared with 25% of the surgically treated (p = 0.05). CONCLUSIONS: This population-based study with long-term follow-up confirms the low incidence of AGI, 1.4%. The similar incidence in the emergency and non-emergency groups suggests that the index operation is not decisive in the development of AGI. The outcome of these infections generally is poor but is worse for non-surgically treated patients.

Lowered Expression of Tumor Suppressor Candidate MYO1C Stimulates Cell Proliferation, Suppresses Cell Adhesion and Activates AKT.

Myosin-1C (MYO1C) is a tumor suppressor candidate located in a region of recurrent losses distal to TP53. Myo1c can tightly and specifically bind to PIP2, the substrate of Phosphoinositide 3-kinase (PI3K), and to Rictor, suggesting a role for MYO1C in the PI3K pathway. This study was designed to examine MYO1C expression status in a panel of well-stratified endometrial carcinomas as well as to assess the biological significance of MYO1C as a tumor suppressor in vitro. We found a significant correlation between the tumor stage and lowered expression of MYO1C in endometrial carcinoma samples. In cell transfection experiments, we found a negative correlation between MYO1C expression and cell proliferation, and MYO1C silencing resulted in diminished cell migration and adhesion. Cells expressing excess of MYO1C had low basal level of phosphorylated protein kinase B (PKB, a.k.a. AKT) and cells with knocked down MYO1C expression showed a quicker phosphorylated AKT (pAKT) response in reaction to serum stimulation. Taken together the present study gives further evidence for tumor suppressor activity of MYO1C and suggests MYO1C mediates its tumor suppressor function through inhibition of PI3K pathway and its involvement in loss of contact inhibition.