A Modern Series of Secondary Aortoenteric Fistula - A 19-Year Experience.

OBJECTIVES: Secondary aortoenteric fistula is a rare and life-threatening condition. Clear evidence on the ideal therapeutic approach is largely missing. This study aims to analyze symptoms, etiology, risk factors, and outcomes based on procedural details. PATIENTS AND METHODS: All patients with secondary aortoenteric fistula admitted between 2003 and 2021 were included. Patient characteristics, surgical procedure details, and postoperative outcomes were analyzed. Outcomes were stratified and compared according to the urgency of operation and the procedure performed. Descriptive statistics were used. The primary endpoint was in-hospital mortality. RESULTS: A total of twentytwo patients (68% male, median age 70 years) were identified. Main symptoms were gastrointestinal bleeding, pain, and fever. From the twentytwo patients ten patients required emergency surgery and ten urgent surgery. Emergency patients were older on average (74 vs 63 years, P = .015) and had a higher risk of postoperative respiratory complications (80% vs 10%, P = .005). Primary open surgery with direct replacement of the aorta or an extra-anatomic bypass with an additional direct suture or resection of the involved bowel was performed in sixteen patients. In four patients underwent endovascular bridging treatment with the definitive approach as a second step. Other two patients died without operation (1x refusal; 1x palliative cancer history). In-hospital mortality was 27%, respectively. Compared to patients undergoing urgent surgery, those treated emergently showed significantly higher in-hospital (50% vs 0%, P = .0033) mortalities. CONCLUSION: Despite rapid diagnosis and treatment, secondary aortoenteric fistula remains a life-threatening condition with 27% in-hospital mortality, significantly increased upon emergency presentation.

External Validity of Randomised Controlled Trials on Carotid Revascularisation: Trial Populations May Not Always Reflect Patients in Clinical Practice.

OBJECTIVE: The external validity of randomised controlled trials (RCTs) and their transferability to clinical practice is under investigated. This study aimed to analyse the exclusion criteria of recent carotid RCTs comparing carotid endarterectomy (CEA) and carotid artery stenting, and to assess the eligibility of consecutive clinical practice cohorts to those RCTs. METHODS: An analysis of the clinical and anatomical exclusion criteria of RCTs for asymptomatic (SPACE-2, ACST-2, CREST-1, and CREST-2) and symptomatic carotid stenosis (SPACE-1, CREST-1, ICSS, and EVA-3S) was performed. Two hundred consecutive asymptomatic and 200 consecutive symptomatic patients, treated by CEA, or transfemoral or transcarotid artery stenting at a tertiary referral university centre were assessed for their potential eligibility for each corresponding RCT. RCT patient data were pooled and differences from the clinical practice cohort analysed. Statistics were descriptive and comparative using Fisher's exact and t tests. RESULTS: The number of clinical and anatomical exclusion criteria differed widely between RCTs. Potential eligibility rates of the clinical practice cohort for RCTs with regard to asymptomatic carotid stenosis were 80.5% (ACST-2), 79.5% (SPACE-2), 47% (CREST-1), and 20% (CREST-2). For RCTs on symptomatic carotid stenosis the eligibility rates were 89% (ICSS), 86.5% (EVA-3S), 64% (SPACE-1), and 39% (CREST-1). Both clinical practice cohorts were older by about three years and patients were more often male vs. the RCTs. Furthermore, a history of smoking (asymptomatic patients), hypertension (symptomatic patients), and atrial fibrillation was diagnosed more often, whereas hypercholesterolaemia and coronary heart disease (asymptomatic patients) were less prevalent. More clinical practice patients were on antiplatelets, anticoagulants, and lipid lowering drugs. Symptomatic clinical practice patients presented more often with retinal ischaemia and less often with minor hemispheric strokes than patients in the RCTs. CONCLUSION: The external validity of contemporary carotid RCTs varies considerably. Patients in routine clinical practice differ from RCT populations with respect to age, comorbidities, and medication. These data are of interest for clinicians and guideline authors and may be relevant for the design of future comparative trials.

Image processing improvements afford second-generation handheld optoacoustic imaging of breast cancer patients.

Background: Since the initial breast transillumination almost a century ago, breast cancer imaging using light has been considered in different implementations aiming to improve diagnostics, minimize the number of available biopsies, or monitor treatment. However, due to strong photon scattering, conventional optical imaging yields low resolution images, challenging quantification and interpretation. Optoacoustic imaging addresses the scattering limitation and yields high-resolution visualization of optical contrast, offering great potential value for breast cancer imaging. Nevertheless, the image quality of experimental systems remains limited due to a number of factors, including signal attenuation with depth and partial view angle and motion effects, particularly in multi-wavelength measurements. Methods: We developed data analytics methods to improve the accuracy of handheld optoacoustic breast cancer imaging, yielding second-generation optoacoustic imaging performance operating in tandem with ultrasonography. Results: We produced the most advanced images yet with handheld optoacoustic examinations of the human breast and breast cancer, in terms of resolution and contrast. Using these advances, we examined optoacoustic markers of malignancy, including vasculature abnormalities, hypoxia, and inflammation, on images obtained from breast cancer patients. Conclusions: We achieved a new level of quality for optoacoustic images from a handheld examination of the human breast, advancing the diagnostic and theranostic potential of the hybrid optoacoustic-ultrasound (OPUS) examination over routine ultrasonography.

Multi-Aspect Optoacoustic Imaging of Breast Tumors under Chemotherapy with Exogenous and Endogenous Contrasts: Focus on Apoptosis and Hypoxia.

Breast cancer is a complex tumor type involving many biological processes. Most chemotherapeutic agents exert their antitumoral effects by rapid induction of apoptosis. Another main feature of breast cancer is hypoxia, which may drive malignant progression and confer resistance to various forms of therapy. Thus, multi-aspect imaging of both tumor apoptosis and oxygenation in vivo would be of enormous value for the effective evaluation of therapy response. Herein, we demonstrate the capability of a hybrid imaging modality known as multispectral optoacoustic tomography (MSOT) to provide high-resolution, simultaneous imaging of tumor apoptosis and oxygenation, based on both the exogenous contrast of an apoptosis-targeting dye and the endogenous contrast of hemoglobin. MSOT imaging was applied on mice bearing orthotopic 4T1 breast tumors before and following treatment with doxorubicin. Apoptosis was monitored over time by imaging the distribution of xPLORE-APOFL750©, a highly sensitive poly-caspase binding apoptotic probe, within the tumors. Oxygenation was monitored by tracking the distribution of oxy- and deoxygenated hemoglobin within the same tumor areas. Doxorubicin treatment induced an increase in apoptosis-depending optoacoustic signal of xPLORE-APOFL750© at 24 h after treatment. Furthermore, our results showed spatial correspondence between xPLORE-APO750© and deoxygenated hemoglobin. In vivo apoptotic status of the tumor tissue was independently verified by ex vivo fluorescence analysis. Overall, our results provide a rationale for the use of MSOT as an effective tool for simultaneously investigating various aspects of tumor pathophysiology and potential effects of therapeutic regimes based on both endogenous and exogenous molecular contrasts.

Chemotherapeutic effects on breast tumor hemodynamics revealed by eigenspectra multispectral optoacoustic tomography (eMSOT).

Non-invasive monitoring of hemodynamic tumor responses to chemotherapy could provide unique insights into the development of therapeutic resistance and inform therapeutic decision-making in the clinic. Methods: Here, we examined the longitudinal and dynamic effects of the common chemotherapeutic drug Taxotere on breast tumor (KPL-4) blood volume and oxygen saturation using eigenspectra multispectral optoacoustic tomography (eMSOT) imaging over a period of 41 days. Tumor vascular function was assessed by dynamic oxygen-enhanced eMSOT (OE-eMSOT). The obtained in vivo optoacoustic data were thoroughly validated by ex vivo cryoimaging and immunohistochemical staining against markers of vascularity and hypoxia. Results: We provide the first preclinical evidence that prolonged treatment with Taxotere causes a significant drop in mean whole tumor oxygenation. Furthermore, application of OE-eMSOT showed a diminished vascular response in Taxotere-treated tumors and revealed the presence of static blood pools, indicating increased vascular permeability. Conclusion: Our work has important translational implications and supports the feasibility of eMSOT imaging for non-invasive assessment of tumor microenvironmental responses to chemotherapy.

Resolution of Spatial and Temporal Heterogeneity in Bevacizumab-Treated Breast Tumors by Eigenspectra Multispectral Optoacoustic Tomography.

Understanding temporal and spatial hemodynamic heterogeneity as a function of tumor growth or therapy affects the development of novel therapeutic strategies. In this study, we employed eigenspectra multispectral optoacoustic tomography (eMSOT) as a next-generation optoacoustic method to impart high accuracy in resolving tumor hemodynamics during bevacizumab therapy in two types of breast cancer xenografts (KPL-4 and MDA-MB-468). Patterns of tumor total hemoglobin concentration (THb) and oxygen saturation (sO2) were imaged in control and bevacizumab-treated tumors over the course of 58 days (KPL-4) and 16 days (MDA-MB-468), and the evolution of functional vasculature "normalization" was resolved macroscopically. An initial sharp drop in tumor sO2 and THb content shortly after the initiation of bevacizumab treatment was followed by a recovery in oxygenation levels. Rim-core subregion analysis revealed steep spatial oxygenation gradients in growing tumors that were reduced after bevacizumab treatment. Critically, eMSOT imaging findings were validated directly by histopathologic assessment of hypoxia (pimonidazole) and vascularity (CD31). These data demonstrate how eMSOT brings new abilities for accurate observation of entire tumor responses to challenges at spatial and temporal dimensions not available by other techniques today. SIGNIFICANCE: Accurate assessment of hypoxia and vascularization over space and time is critical for understanding tumor development and the role of spatial heterogeneity in tumor aggressiveness, metastasis, and response to treatment.

Fluorescence imaging reversion using spatially variant deconvolution.

Fluorescence imaging opens new possibilities for intraoperative guidance and early cancer detection, in particular when using agents that target specific disease features. Nevertheless, photon scattering in tissue degrades image quality and leads to ambiguity in fluorescence image interpretation and challenges clinical translation. We introduce the concept of capturing the spatially-dependent impulse response of an image and investigate Spatially Adaptive Impulse Response Correction (SAIRC), a method that is proposed for improving the accuracy and sensitivity achieved. Unlike classical methods that presume a homogeneous spatial distribution of optical properties in tissue, SAIRC explicitly measures the optical heterogeneity in tissues. This information allows, for the first time, the application of spatially-dependent deconvolution to correct the fluorescence images captured in relation to their modification by photon scatter. Using experimental measurements from phantoms and animals, we investigate the improvement in resolution and quantification over non-corrected images. We discuss how the proposed method is essential for maximizing the performance of fluorescence molecular imaging in the clinic.

Multispectral Optoacoustic Tomography of Benign and Malignant Thyroid Disorders: A Pilot Study.

This study aimed at evaluating hybrid multispectral optoacoustic tomography/ultrasound for imaging of thyroid disorders, including Graves' disease and thyroid nodules. Methods: The functional biomarkers and tissue parameters deoxygenated hemoglobin, oxygenated hemoglobin, total hemoglobin, saturation of hemoglobin, fat content, and water content were analyzed in thyroid lobes affected by Graves' disease (n = 6), thyroid lobes with healthy tissue (n = 8), benign thyroid nodules (n = 13), and malignant thyroid nodules (n = 3). Results: In Graves' disease, significantly higher deoxygenated hemoglobin (3.18 ± 0.52 vs. 2.13 ± 0.62; P = 0.0055) and total hemoglobin (8.34 ± 0.88 vs. 6.59 ± 1.16; P = 0.0084) and significantly lower fat content (0.64 ± 0.37 vs. 1.69 ± 1.25; P = 0.0293) were found than in healthy controls. Malignant thyroid nodules showed significantly lower saturation of hemoglobin (55.4% ± 2.6% vs. 60.8% ± 7.2%; P = 0.0393) and lower fat content (0.62 ± 0.19 vs. 1.46 ± 0.87; P = 0.1295) than benign nodules. Conclusion: This pilot study showed the applicability and the potential of hybrid multispectral optoacoustic tomography/ultrasound to semiquantitatively provide tissue characterization and functional parameters in thyroid disorders for improved noninvasive diagnostics of thyroid diseases.

Quality appraisal of systematic reviews, and meta-analysis of the hospital/surgeon-linked volume-outcome relationship of carotid revascularization procedures.

INTRODUCTION: Several systematic reviews and meta-analyses of primary studies have been published on the relationship between annual case load of carotid endarterectomy (CEA) and carotid artery stenting (CAS) performed at hospital level or by individual surgeons, and perioperative outcomes. Many studies on volume-outcome relationship have already been published and high-quality systematic reviews are crucial for further guideline development. EVIDENCE ACQUISITION: Systematic reviews and meta-analyses on the relationship between hospital or surgeon CEA/CAS volume and periprocedural outcomes were identified through a systematic literature search of Medline, Web of Science, and the Cochrane Database of Systematic Reviews. Methodological quality of the systematic reviews was appraised using the AMSTAR2 tool independently by two authors. Systematic reviews were aggregated in their volume-outcome findings. Quantitative data from primary studies included in the systematic reviews were synthesized. Additionally, volume definitions and the time point of outcome assessment used in primary studies were analyzed. EVIDENCE SYNTHESIS: In total, five systematic reviews published between 2000 and 2018 were identified, each comprising 11-25 primary studies. Methodological quality appraisal of these reviews revealed high quality for only the most recent review, low quality for three reviews, and critically low quality in one review. Aggregation of the systematic reviews revealed a significant inverse relationship between hospital/operator volume and the periprocedural risk of death or stroke following CEA. For CAS, high operator volume was associated with lower outcome rates. Regarding hospital volume, an inverse but non-significant relationship between CAS hospital volume and outcome rate was found. In our synthesis of primary studies from these systematic reviews an inverse CEA hospital and operator volume relationship was present for stroke or death and for CAS for hospital volume, respectively. A high heterogeneity regarding the definitions of volume categories, and of time points assessing outcomes was apparent. CONCLUSIONS: For CEA, high quality aggregated evidence revealed an inverse relationship between hospital/surgeon CEA volume and periprocedural rate of stroke or death. The same was true for operator linked CAS volume. Regarding hospital linked CAS volume, no unequivocal evidence was found. Additionally, heterogeneity was found regarding volume definition, and time of outcome assessment. Thus, future studies should aim to harmonize volume definitions and outcome time points.

Biobanking: Objectives, Requirements, and Future Challenges-Experiences from the Munich Vascular Biobank.

Collecting biological tissue samples in a biobank grants a unique opportunity to validate diagnostic and therapeutic strategies for translational and clinical research. In the present work, we provide our long-standing experience in establishing and maintaining a biobank of vascular tissue samples, including the evaluation of tissue quality, especially in formalin-fixed paraffin-embedded specimens (FFPE). Our Munich Vascular Biobank includes, thus far, vascular biomaterial from patients with high-grade carotid artery stenosis (n = 1567), peripheral arterial disease (n = 703), and abdominal aortic aneurysm (n = 481) from our Department of Vascular and Endovascular Surgery (January 2004⁻December 2018). Vascular tissue samples are continuously processed and characterized to assess tissue morphology, histological quality, cellular composition, inflammation, calcification, neovascularization, and the content of elastin and collagen fibers. Atherosclerotic plaques are further classified in accordance with the American Heart Association (AHA), and plaque stability is determined. In order to assess the quality of RNA from FFPE tissue samples over time (2009⁻2018), RNA integrity number (RIN) and the extent of RNA fragmentation were evaluated. Expression analysis was performed with two housekeeping genes-glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and beta-actin (ACTB)-using TaqMan-based quantitative reverse-transcription polymerase chain reaction (qRT)-PCR. FFPE biospecimens demonstrated unaltered RNA stability over time for up to 10 years. Furthermore, we provide a protocol for processing tissue samples in our Munich Vascular Biobank. In this work, we demonstrate that biobanking is an important tool not only for scientific research but also for clinical usage and personalized medicine.

Comprehensive phantom for interventional fluorescence molecular imaging.

Fluorescence imaging has been considered for over a half-century as a modality that could assist surgical guidance and visualization. The administration of fluorescent molecules with sensitivity to disease biomarkers and their imaging using a fluorescence camera can outline pathophysiological parameters of tissue invisible to the human eye during operation. The advent of fluorescent agents that target specific cellular responses and molecular pathways of disease has facilitated the intraoperative identification of cancer with improved sensitivity and specificity over nonspecific fluorescent dyes that only outline the vascular system and enhanced permeability effects. With these new abilities come unique requirements for developing phantoms to calibrate imaging systems and algorithms. We briefly review herein progress with fluorescence phantoms employed to validate fluorescence imaging systems and results. We identify current limitations and discuss the level of phantom complexity that may be required for developing a universal strategy for fluorescence imaging calibration. Finally, we present a phantom design that could be used as a tool for interlaboratory system performance evaluation.