A Pilot Cost-Effectiveness Analysis of Treatments in Newly Diagnosed High-Grade Gliomas: The Example of 5-Aminolevulinic Acid Compared With White-Light Surgery

BACKGROUND: High-grade gliomas are aggressive, incurable tumors characterized by extensive diffuse invasion of the normal brain parenchyma. Novel therapies at best prolong survival; their costs are formidable and benefit is marginal. Economic restrictions thus require knowledge of the cost-effectiveness of treatments. Here, we show the cost-effectiveness of enhanced resections in malignant glioma surgery using a well-characterized tool for intraoperative tumor visualization, 5-aminolevulinic acid (5-ALA). OBJECTIVE: To evaluate the cost-effectiveness of 5-ALA fluorescence-guided neurosurgery compared with white-light surgery in adult patients with newly diagnosed high-grade glioma, adopting the perspective of the Portuguese National Health Service. METHODS: We used a Markov model (cohort simulation). Transition probabilities were estimated with the use of data from 1 randomized clinical trial and 1 noninterventional prospective study. Utility values and resource use were obtained from published literature and expert opinion. Unit costs were taken from official Portuguese reimbursement lists (2012 values). The health outcomes considered were quality-adjusted life-years, lifeyears, and progression-free life-years. Extensive 1-way and probabilistic sensitivity analyses were performed. RESULTS: The incremental cost-effectiveness ratios are below €10 000 in all evaluated outcomes, being around €9100 per quality-adjusted life-year gained, €6700 per life-year gained, and €8800 per progression-free life-year gained. The probability of 5-ALA fluorescence-guided surgery cost-effectiveness at a threshold of €20000 is 96.0% for quality-adjusted life-year, 99.6% for life-year, and 98.8% for progression-free life-year. CONCLUSION: 5-ALA fluorescence-guided surgery appears to be cost-effective in newly diagnosed high-grade gliomas compared with white-light surgery. This example demonstrates cost-effectiveness analyses for malignant glioma surgery to be feasible on the basis of existing data.

Variation in Haemodynamic Monitoring for Major Surgery in European Nations: Secondary Analysis of the EuSOS Dataset

BACKGROUND: The use of cardiac output monitoring may improve patient outcomes after major surgery. However, little is known about the use of this technology across nations. METHODS: This is a secondary analysis of a previously published observational study. Patients aged 16 years and over undergoing major non-cardiac surgery in a 7-day period in April 2011 were included into this analysis. The objective is to describe prevalence and type of cardiac output monitoring used in major surgery in Europe. RESULTS: Included in the analysis were 12,170 patients from the surgical services of 426 hospitals in 28 European nations. One thousand four hundred and sixteen patients (11.6 %) were exposed to cardiac output monitoring, and 2343 patients (19.3 %) received a central venous catheter. Patients with higher American Society of Anesthesiologists (ASA) scores were more frequently exposed to cardiac output monitoring (ASA I and II, 643 patients [8.6 %]; ASA III-V, 768 patients [16.2 %]; p < 0.01) and central venous catheter (ASA I and II, 874 patients [11.8 %]; ASA III-V, 1463 patients [30.9 %]; p < 0.01). In elective surgery, 990 patients (10.8 %) were exposed to cardiac output monitoring, in urgent surgery 252 patients (11.7 %) and in emergency surgery 173 patients (19.8 %). A central venous catheter was used in 1514 patients (16.6 %) undergoing elective, in 480 patients (22.2 %) undergoing urgent and in 349 patients (39.9 %) undergoing emergency surgery. Nine hundred sixty patients (7.9 %) were monitored using arterial waveform analysis, 238 patients (2.0 %) using oesophageal Doppler ultrasound, 55 patients (0.5 %) using a pulmonary artery catheter and 44 patients (2.0 %) using other technologies. Across nations, cardiac output monitoring use varied from 0.0 % (0/249 patients) to 27.5 % (19/69 patients), whilst central venous catheter use varied from 5.6 % (7/125 patients) to 43.2 % (16/37 patients). CONCLUSIONS: One in ten patients undergoing major surgery is exposed to cardiac output monitoring whilst one in five receives a central venous catheter. The use of both technologies varies widely across Europe.

Adhesion Prevention in Laparoscopic Surgery

Adhesions have important consequences for patients, surgeons, and health services. Peritonealtissue injury can be prevented by using careful surgical techniques. A large number of antiadhesion products have been used experimentally and clinically to prevent postoperative adhesions. Methods: The current author reviewed the surgical literature published about epidemiology, pathogenesis, and various prevention strategies of adhesion formation. Results: Meticulous surgery is essential to reduce unnecessary morbidity and mortality rates from these untoward effects of surgery. Several preventive agents against postoperative peritoneal adhesions have been investigated. Bioresorbable membranes are site-specific antiadhesion products but may be more difficult to use laparoscopically. Liquids and gels have the advantage of more-widespread areas of action and increased ease of use, particularly during laparoscopic operations. Effective pharmacologic agents that can reduce release of proinflammatory cytokines or activate peritoneal fibrinolysis are under development. Their results are encouraging but most of them are contradictory. Conclusions: Many modalities are being studied to reduce this risk; despite initial promising results of different measures in postoperative adhesion prevention, none of them have become standard applications. With the current state of knowledge, preclinical or clinical studies are still necessary to evaluate the effectiveness of the several proposed prevention strategies for avoiding postoperative peritoneal adhesions.

Coronary Revascularization Induces a Shift From Cardiac Toward Noncardiac Mortality Without Improving Survival in Vascular Surgery Patient

OBJECTIVE: Although evidence has shown that ischemic heart disease (IHD) in vascular surgery patients has a negative impact on the prognosis after surgery, it is unclear whether directed treatment of IHD may influence cause-specific and overall mortality. The objective of this study was to determine the prognostic implication of coronary revascularization (CR) on overall and cause-specific mortality in vascular surgery patients. METHODS: Patients undergoing surgery for abdominal aortic aneurysm, carotid artery stenosis, or peripheral artery disease in a university hospital in The Netherlands between January 2003 and December 2011 were retrospectively included. Survival estimates were obtained by Kaplan-Meier and Cox regression analysis. RESULTS: A total of 1104 patients were included. Adjusted survival analyses showed that IHD significantly increased the risk of overall mortality (hazard ratio [HR], 1.50; 95% confidence interval, 1.21-1.87) and cardiovascular death (HR, 1.93; 95% confidence interval, 1.35-2.76). Compared with those without CR, patients previously undergoing CR had similar overall mortality (HR, 1.38 vs 1.62; P = .274) and cardiovascular mortality (HR, 1.83 vs 2.02; P = .656). Nonrevascularized IHD patients were more likely to die of IHD (6.9% vs 35.7%), whereas revascularized IHD patients more frequently died of cardiovascular causes unrelated to IHD (39.1% vs 64.3%; P = .018). CONCLUSIONS: This study confirms the significance of IHD for postoperative survival of vascular surgery patients. CR was associated with lower IHD-related death rates. However, it failed to provide an overall survival benefit because of an increased rate of cardiovascular mortality unrelated to IHD. Intensification of secondary prevention regimens may be required to prevent this shift toward non-IHD-related death and thereby improve life expectancy.

Low Socioeconomic Status is an Independent Risk Factor for Survival After Abdominal Aortic Aneurysm Repair and Open Surgery for Peripheral Artery Disease

OBJECTIVE/BACKGROUND: The association between socioeconomic status (SES), presentation, and outcome after vascular surgery is largely unknown. This study aimed to determine the influence of SES on post-operative survival and severity of disease at presentation among vascular surgery patients in the Dutch setting of equal access to and provision of care. METHODS: Patients undergoing surgical treatment for peripheral artery disease (PAD), abdominal aortic aneurysm (AAA), or carotid artery stenosis between January 2003 and December 2011 were retrospectively included. The association between SES, quantified by household income, disease severity at presentation, and survival was studied using logistic and Cox regression analysis adjusted for demographics, and medical and behavioral risk factors. RESULTS: A total of 1,178 patients were included. Low income was associated with worse post-operative survival in the PAD cohort (n = 324, hazard ratio 1.05, 95% confidence interval [CI] 1.00-1.10, per 5,000 Euro decrease) and the AAA cohort (n = 440, quadratic relation, p = .01). AAA patients in the lowest income quartile were more likely to present with a ruptured aneurysm (odds ratio [OR] 2.12, 95% CI 1.08-4.17). Lowest income quartile PAD patients presented more frequently with symptoms of critical limb ischemia, although no significant association could be established (OR 2.02, 95% CI 0.96-4.26). CONCLUSIONS: The increased health hazards observed in this study are caused by patient related factors rather than differences in medical care, considering the equality of care provided by the study setting. Although the exact mechanism driving the association between SES and worse outcome remains elusive, consideration of SES as a risk factor in pre-operative decision making and focus on treatment of known SES related behavioral and psychosocial risk factors may improve the outcome of patients with vascular disease.

Acute Kidney Injury after Pediatric Cardiac Surgery: Risk Factors and Outcomes. Proposal for a Predictive Model

Objectives: To characterize the epidemiology and risk factors for acute kidney injury (AKI) after pediatric cardiac surgery in our center, to determine its association with poor short-term outcomes, and to develop a logistic regression model that will predict the risk of AKI for the study population. Methods: This single-center, retrospective study included consecutive pediatric patients with congenital heart disease who underwent cardiac surgery between January 2010 and December 2012. Exclusion criteria were a history of renal disease, dialysis or renal transplantation. Results: Of the 325 patients included, median age three years (1 day---18 years), AKI occurred in 40 (12.3%) on the first postoperative day. Overall mortality was 13 (4%), nine of whom were in the AKI group. AKI was significantly associated with length of intensive care unit stay, length of mechanical ventilation and in-hospital death (p<0.01). Patients’ age and postoperative serum creatinine, blood urea nitrogen and lactate levels were included in the logistic regression model as predictor variables. The model accurately predicted AKI in this population, with a maximum combined sensitivity of 82.1% and specificity of 75.4%. Conclusions: AKI is common and is associated with poor short-term outcomes in this setting. Younger age and higher postoperative serum creatinine, blood urea nitrogen and lactate levels were powerful predictors of renal injury in this population. The proposed model could be a useful tool for risk stratification of these patients.

A comparison between digital breast tomosynthesis and mammography: dosimetric and image quality characterization of clinical system

Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica

Pseudoneoplastic lesion of the breast caused by Schistosoma mansoni

A case of a pseudoneoplastic lesion of the breast clinically and sonographically suggestive of a fibroadenoma is reported. Excisional biopsy revealed the nodule was an inflammatory process consequent to infection by Schistosoma mansoni.

Optimization of breast tomosynthesis image reconstruction using parallel computing

Breast cancer is the most common cancer among women, being a major public health problem. Worldwide, X-ray mammography is the current gold-standard for medical imaging of breast cancer. However, it has associated some well-known limitations. The false-negative rates, up to 66% in symptomatic women, and the false-positive rates, up to 60%, are a continued source of concern and debate. These drawbacks prompt the development of other imaging techniques for breast cancer detection, in which Digital Breast Tomosynthesis (DBT) is included. DBT is a 3D radiographic technique that reduces the obscuring effect of tissue overlap and appears to address both issues of false-negative and false-positive rates. The 3D images in DBT are only achieved through image reconstruction methods. These methods play an important role in a clinical setting since there is a need to implement a reconstruction process that is both accurate and fast. This dissertation deals with the optimization of iterative algorithms, with parallel computing through an implementation on Graphics Processing Units (GPUs) to make the 3D reconstruction faster using Compute Unified Device Architecture (CUDA). Iterative algorithms have shown to produce the highest quality DBT images, but since they are computationally intensive, their clinical use is currently rejected. These algorithms have the potential to reduce patient dose in DBT scans. A method of integrating CUDA in Interactive Data Language (IDL) is proposed in order to accelerate the DBT image reconstructions. This method has never been attempted before for DBT. In this work the system matrix calculation, the most computationally expensive part of iterative algorithms, is accelerated. A speedup of 1.6 is achieved proving the fact that GPUs can accelerate the IDL implementation.

Transimpedance amplifier for early detection of breast cancer

Breast cancer is the most common type of cancer worldwide. The effectiveness of its treatment depends on early stage detection, as well as on the accuracy of its diagnosis. Recently, diagnosis techniques have been submitted to relevant breakthroughs with the upcoming of Magnetic Resonance Imaging, Ultrasound Sonograms and Positron Emission Tomography (PET) scans, among others. The work presented here is focused on studying the application of a PET system to a Positron Emission Mammography (PEM) system. A PET/PEM system works under the principle that a scintillating crystal will detect a gamma-ray pulse, originated at the cancerous cells, converting it into a correspondent visible light pulse. The latter must then be converted into an electrical current pulse by means of a Photo- -Sensitive Device (PSD). After the PSD there must be a Transimpedance Amplifier (TIA) in order to convert the current pulse into a suitable output voltage, in a time period lower than 40 ns. In this Thesis, the PSD considered is a Silicon Photo-Multiplier (SiPM). The usage of this recently developed type of PSD is impracticable with the conventional TIA topologies, as it will be proven. Therefore, the usage of the Regulated Common-Gate (RCG) topology will be studied in the design of the amplifier. There will be also presented two RCG variations, comprising a noise response improvement and differential operation of the circuit. The mentioned topology will also be tested in a Radio-Frequency front-end, showing the versatility of the RCG. A study comprising a low-voltage self-biasing feedback TIA will also be shown. The proposed circuits will be simulated with standard CMOS technology (UMC 130 nm), using a 1.2 V power supply. A power consumption of 0.34 mW with a signal-to-noise ratio of 43 dB was achieved.

Assessment of Notch1 ligands production - key protein targets in breast cancer

Cell-to-cell communication is required for many biological processes in development and adult life. One of the most common systems utilized by a wide range of eukaryotes is the Notch signalling pathway. Four Notch receptors and five ligands have been identified in mammals that interact via their extracellular domains leading to transcription activation. Studies have shown that the Notch ligands expression is undetectable in normal breast tissues, but moderate to high expression has been detected in breast cancer. Thus, any of the Notch1 ligands can be studied as possible therapeutic targets for breast cancer. To study Notch pathway proteins there is the need to obtain stable protein solutions. E. coli is the host of excellence for recombinant proteins for the ease of use, fast growth and high cell densities. However, the expression of mammalian proteins in such systems may overwhelm the bacterial cellular machinery, which does not possess the ability for post-translational modifications, or dedicated compartments for protein synthesis. Mammalian cells are therefore preferred, despite their technical and financial increased demands. We aim to determine the best expression and purification conditions for the different ligand protein constructs, to develop specific function-blocking antibodies using the Phage Display technology. Moreover, we propose to crystallize the Notch1 ligands alone and in complex with the phage display selected antibodies, unveiling molecular details. hJag2DE3 and hDll1DE6 proteins were purified from refolded inclusion bodies or mammalian cell culture supernatants, respectively, and purity was confirmed by SDS-PAGE (>95%). Protein produced in mammalian cells showed to be more stable, apparently with the physiological disulfide pattern, contrary to what was observed in the refolded protein. Several nano-scale crystallization experiments were set up in 96-well plates, but no positive result was obtained. We will continue to pursue for the best expression for the Notch ligand constructs in both expression systems.

Microwave imaging of the axilla to aid breast cancer diagnosis

Breast cancer is the most common type of cancer among women all over the world. An important issue that is not commonly addressed in breast cancer imaging literature is the importance of imaging the underarm region—where up to 80% of breast cancer cells can metastasise to. The first axillary lymph nodes to receive drainage from the primary tumour in the breast are called Sentinel Node. If cancer cells are found in the Sentinel Node, there is an increased risk of metastatic breast cancer which makes this evaluation crucial to decide what follow-up exams and therapy to follow. However, non-invasive detection of cancer cells in the lymph nodes is often inconclusive, leading to the surgical removal of too many nodes which causes adverse side-effects for patients. Microwave Imaging is one of the most promising non-invasive imaging modalities for breast cancer early screening and monitoring. This novel study tests the feasibility of imaging the axilla region by means of the simulation of an Ultra-Wideband Microwave Imaging system. Simulations of such system are completed in several 2D underarm models that mimic the axilla. Initial imaging results are obtained by means of processing the simulated backscattered signals by eliminating artefacts caused by the skin and beamforming the processed signals in order to time-align all the signals recorded at each antenna. In this dissertation several image formation algorithms are implemented and compared by visual inspection of the resulting images and through a range of performance metrics, such as Signal-to-Clutter Ratio and FullWidth Half Maximum calculations. The results in this study showed that Microwave Imaging is a promising technique that might allow to identify the presence and location of metastasised cancer cells in axillary lymph nodes, enabling the non-invasive evaluation of breast cancer staging.

Phage display as a tool for development of novel therapeutics for breast cancer

Phage display technology is a powerful platform for the generation of highly specific human monoclonal antibodies (Abs) with potential use in clinical applications. Moreover, this technique has also proven to be a reliable approach in identifying and validating new cancer-related targets. For scientific or medical applications, different types of Ab libraries can be constructed. The use of Fab Immune libraries allows the production of high quality and affinity antigen-specific Abs. In this work, two immune human phage display IgG Fab libraries were generated from the Ab repertoire of 16 breast cancer patients, in order to obtain a tool for the development of new therapeutic Abs for breast cancer, a condition that has great impact worldwide. The generated libraries are estimated to contain more than 108 independent clones and a diversity over 90%. Libraries validation was pursued by selection against BSA, a foreign and highly immunogenic protein, and HER2, a well established cancer target. Preliminary results suggested that phage pools with affinity for these antigens were selected and enriched. Individual clones were isolated, however, it was not possible to obtain enough data to further characterize them. Selection against the DLL1 protein was also performed, once it is a known ligand of the Notch pathway, whose deregulation is associated to breast cancer, making it an interesting target for the generation of function-blocking Abs. Selection resulted in the isolation of a clone with low affinity and Fab expression levels. The validation process was not completed and further effort will have to be put in this task in the future. Although immune libraries concept implies limited applicability, the library reported here has a wide range of use possibilities, since it was not restrained to a single antigen but instead thought to be used against any breast cancer associated target, thus being a valuable tool.