A cardiovascular simulator tailored for training and clinical uses.

OBJECTIVE: In the present work a cardiovascular simulator designed both for clinical and training use is presented. METHOD: The core of the simulator is a lumped parameter model of the cardiovascular system provided with several modules for the representation of baroreflex control, blood transfusion, ventricular assist device (VAD) therapy and drug infusion. For the training use, a Pre-Set Disease module permits to select one or more cardiovascular diseases with a different level of severity. For the clinical use a Self-Tuning module was implemented. In this case, the user can insert patient's specific data and the simulator will automatically tune its parameters to the desired hemodynamic condition. The simulator can be also interfaced with external systems such as the Specialist Decision Support System (SDSS) devoted to address the choice of the appropriate level of VAD support based on the clinical characteristics of each patient. RESULTS: The Pre-Set Disease module permits to reproduce a wide range of pre-set cardiovascular diseases involving heart, systemic and pulmonary circulation. In addition, the user can test different therapies as drug infusion, VAD therapy and volume transfusion. The Self-Tuning module was tested on six different hemodynamic conditions, including a VAD patient condition. In all cases the simulator permitted to reproduce the desired hemodynamic condition with an error<10%. CONCLUSIONS: The cardiovascular simulator could be of value in clinical arena. Clinicians and students can utilize the Pre-Set Diseases module for training and to get an overall knowledge of the pathophysiology of common cardiovascular diseases. The Self-Tuning module is prospected as a useful tool to visualize patient's status, test different therapies and get more information about specific hemodynamic conditions. In this sense, the simulator, in conjunction with SDSS, constitutes a support to clinical decision - making.

A decision support system for the treatment of patients with ventricular assist device support.

BACKGROUND: Heart failure (HF) is affecting millions of people every year and it is characterized by impaired ventricular performance, exercise intolerance and shortened life expectancy. Despite significant advancements in drug therapy, mortality of the disease remains excessively high, as heart transplant remains the gold standard treatment for end-stage HF when no contraindications subsist. Traditionally, implanted Ventricular Assist Devices (VADs) have been employed in order to provide circulatory support to patients who cannot survive the waiting time to transplantation, reducing the workload imposed on the heart. In many cases that process could recover its contractility performance. OBJECTIVES: The SensorART platform focuses on the management and remote treatment of patients suffering from HF. It provides an interoperable, extendable and VAD-independent solution, which incorporates various hardware and software components in a holistic approach, in order to improve the quality of the patients' treatment and the workflow of the specialists. This paper focuses on the description and analysis of Specialist's Decision Support System (SDSS), an innovative component of the SensorART platform. METHODS: The SDSS is a Web-based tool that assists specialists on designing the therapy plan for their patients before and after VAD implantation, analyzing patients' data, extracting new knowledge, and making informative decisions. RESULTS: SDSS offers support to medical and VAD experts through the different phases of VAD therapy, incorporating several tools covering all related fields; Statistics, Association Rules, Monitoring, Treatment, Weaning, Speed and Suction Detection. CONCLUSIONS: SDSS and its modules have been tested in a number of patients and the results are encouraging.

ART-ML: a new markup language for modelling and representation of biological processes in cardiovascular diseases.

BACKGROUND: With an ever increasing number of biological models available on the internet, a standardized modelling framework is required to allow information to be accessed and visualized. OBJECTIVE: In this paper we propose a novel Extensible Markup Language (XML) based format called ART-ML that aims at supporting the interoperability and the reuse of models of geometry, blood flow, plaque progression and stent modelling, exported by any cardiovascular disease modelling software. ART-ML has been developed and tested using ARTool. ARTool is a platform for the automatic processing of various image modalities of coronary and carotid arteries. METHODS: The images and their content are fused to develop morphological models of the arteries in 3D representations. All the above described procedures integrate disparate data formats, protocols and tools. ART-ML proposes a representation way, expanding ARTool, for interpretability of the individual resources, creating a standard unified model for the description of data and, consequently, a format for their exchange and representation that is machine independent. More specifically, ARTool platform incorporates efficient algorithms which are able to perform blood flow simulations and atherosclerotic plaque evolution modelling. Integration of data layers between different modules within ARTool are based upon the interchange of information included in the ART-ML model repository. ART-ML provides a markup representation that enables the representation and management of embedded models within the cardiovascular disease modelling platform, the storage and interchange of well-defined information. RESULTS: The corresponding ART-ML model incorporates all relevant information regarding geometry, blood flow, plaque progression and stent modelling procedures. All created models are stored in a model repository database which is accessible to the research community using efficient web interfaces, enabling the interoperability of any cardiovascular disease modelling software models. CONCLUSIONS: ART-ML can be used as a reference ML model in multiscale simulations of plaque formation and progression, incorporating all scales of the biological processes.

Multiscale-patient-specific artery and atherogenesis models.

In this work, we present a platform for the development of multiscale patient-specific artery and atherogenesis models. The platform, called ARTool, integrates technologies of 3-D image reconstruction from various image modalities, blood flow and biological models of mass transfer, plaque characterization, and plaque growth. Patient images are acquired for the development of the 3-D model of the patient specific arteries. Then, blood flow is modeled within the arterial models for the calculation of the wall shear stress distribution (WSS). WSS is combined with other patient-specific parameters for the development of the plaque progression models. Real-time simulation can be performed for same cases in grid environment. The platform is evaluated using both animal and human data.

ART-ML - a novel XML format for the biological procedures modeling and the representation of blood flow simulation.

The paper proposes a novel Extensible Markup Language (XML) based format called ART-ML that aims at supporting the interoperability and the reuse of models of blood flow, mass transport and plaque formation, exported by ARTool. ARTool is a platform for the automatic processing of various image modalities of coronary and carotid arteries. The images and their content are fused to develop morphological models of the arteries in easy to handle 3D representations. The platform incorporates efficient algorithms which are able to perform blood flow simulation. In addition atherosclerotic plaque development is estimated taking into account morphological, flow and genetic factors. ART-ML provides a XML format that enables the representation and management of embedded models within the ARTool platform and the storage and interchange of well-defined information. This approach influences in the model creation, model exchange, model reuse and result evaluation.

A non-invasive methodology for fetal monitoring during pregnancy.

OBJECTIVES: This paper describes a methodology for the monitoring of the fetal cardiac health status during pregnancy, through the effective and non-invasive monitoring of the abdominal ECG signals (abdECG) of the mother. METHODS: For this purpose, a three-stage methodology has been developed. In the first stage, the fetal heart rate (fHR) is extracted from the abdECG signals, using nonlinear analysis. Also, the eliminated ECG (eECG) is calculated, which is the abdECG after the maternal QRSs elimination. In the second stage, a blind source separation technique is applied to the eECG signals and the fetal ECG (fECG) is obtained. Finally, monitoring of the fetus is implemented using features extracted from the fHR and fECG, such as the T/QRS ratio and the characterization of the fetal ST waveforms. RESULTS: The methodology is evaluated using a dataset of simulated multichannel abdECG signals: 94.79% accuracy for fHR extraction, 92.49% accuracy in T/QRS ratio calculation and 79.87% in ST waveform classification. CONCLUSIONS: The novel non-invasive proposed methodology is advantageous since it offers automated identification of fHR and fECG and automated ST waveform analysis, exhibiting a high diagnostic accuracy.

Fetal heart rate detection in multivariate abdominal ECG recordings using non-linear analysis.

A novel three-stage methodology for the detection of fetal heart rate (fHR) from multivariate abdominal electrocardiogram (ECG) recordings is introduced. In the first stage, the maternal R-peaks and fiducial points (maternal QRS onset and offset) are detected. Maternal fiducial points are used to eliminate the maternal QRS complexes from the abdominal ECG recordings. In the second stage, two denoising procedures are applied to enhance the fetal QRS complexes. The phase space characteristics are employed to identify fetal heart beats not overlapping with the maternal QRSs which are eliminated in the first stage. The extraction of the fetal heart rate is accomplished in the third stage, using a histogram based technique in order to identify the location of the fetal heart beats which overlap with the maternal QRSs. The methodology is evaluated on simulated and real multichannel ECG signals. In both cases, the obtained results indicate high performance; in the simulated ECGs the accuracy ranges from 74.21-100%, depending on the employed SNR, while in the real recordings the average accuracy is 94.08%.

Advantages of laparoscopic stented choledochorrhaphy over T-tube placement.

BACKGROUND: Postoperative complications after laparoscopic choledochotomy are mainly related to the T tube. Both laparoscopic endobiliary stent placement with primary closure of the common bile duct (CBD) and primary closure of the CBD without drainage have been proposed as safe and effective alternatives to T tube placement. METHODS: This was a retrospective analysis of data collected prospectively on 53 consecutive patients suffering from proven choledocholithiasis who underwent laparoscopic CBD exploration through a choledochotomy between January 1999 and January 2003. In the early period a T tube was placed at the end of the procedure (n = 32). Biliary stent placement and primary CBD closure was performed from June 2001 (n = 21). RESULTS: There were no significant differences in epidemiological characteristics, preoperative factors or intraoperative findings between the groups. Seven patients developed complications, six in the T tube group and one in the stent group. Univariate analysis revealed a significantly lower morbidity rate and shorter postoperative hospital stay in the stent group. CONCLUSION: Placement of a biliary endoprosthesis after laparoscopic choledochotomy achieves biliary decompression, and avoids the complications of a T tube, leading to a shorter postoperative hospital stay. The method is a safe and effective alternative method of CBD drainage after laparoscopic choledochotomy.

Bile duct varices in the absence of portal hypertension signs.

Previous reports have shown that unrecognized or incidental bile duct varices have been reported as being related to hazardous complications and difficulties during surgery or other interventional procedures. A 32-year-old Indian female patient with no previous symptoms and signs suggestive of portal hypertension was admitted for an elective laparoscopic cholecystectomy for biliary colic. Bile duct varices were incidentally recognized during the operation. For the sake of safety, the surgery was converted to a conventional approach. Postoperatively, a detailed history revealed catheterization of the umbilical vein during the newborn period. Subsequently, contrast-enhanced computer tomography scanning showed extrahepatic portal vein thrombosis and cavernous transformation, while an upper gastrointestinal tract endoscopy did not reveal any evidence of esophageal varices. Bile duct varices should be excluded in patients with symptoms and signs suggestive for portal hypertension. Moreover, the present case addresses the fact that bile duct varices should also be suspected in asymptomatic patients with a history suggestive for extrahepatic portal vein thrombosis. Intraoperative recognition of bile duct varices requires a careful anatomical approach to the hepatoduodenal ligament to avoid hazardous complications.

Resection of renal metastases to the pancreas: a surgical challenge.

BACKGROUND: Metastasis to the pancreas from renal cell carcinoma (RCC) is distinctly uncommon. Most cases are detected at an advanced stage of the disease and are thus unsuitable for resection. A solitary RCC metastasis to the head of pancreas is rarely encountered and, although it is potentially amenable to surgical resection, surgeons may be hesitant to perform pancreatoduodenectomy. CASES OUTLINES: Two patients with a solitary RCC metastasis to the head of pancreas were treated by pancreatoduodenectomy, while a third with multiple RCC metastases declined any treatment. Two of the patients were asymptomatic, and one presented with anaemia and mild abdominal pain. Computed tomography (CT) and angiography were used to exclude other metastases and to assess resectability of the pancreatic tumour. All three patients are still alive, those with resectable disease at 2 years and 9 years and the one with irresectable disease at 4 years. DISCUSSION: Isolated RCC metastasis to the pancreas is a rare event. Patients present either on follow-up imaging or with symptoms such as mild abdominal pain, weight loss, jaundice, anaemia or gastrointestinal bleeding (whether occult or overt). Dynamic spiral CT can visualise the tumour and exclude distant metastasis. Angiography often reveals a highly vascularised tumour and will help to assess resectability. In the absence of widespread disease, pancreatic resection can provide long-term survival in metastatic RCC, although few cases have been reported with lengthy follow-up. The prognosis is better than for pancreatic adenocarcinoma.

Large lipoma of the vulva.

Vulvar lipoma is a rare entity. A 52-year-old woman presented with a large mass arising in the right major labium. CT scan revealed that the mass contained adipose tissue. During operation a lipomatous tumor was found which at histologic examination proved to be a lipoma.

Retroperitoneal mucinous cystadenoma.

A case of retroperitoneal mucinous cystadenoma histologically confirmed in a 21-year-old woman is reported. Although ultrasound, CT and MR detected the tumor, a preoperative diagnosis could not be established by imaging methods. The cystic tumor was removed and microscopic examination revealed a mucinous cystadenoma. Mullerian mesothelial metaplasia of peritoneal invagination into the retroperitoneal space is the most likely explanation for the histogenesis of these tumors.