Understanding (patho)physiological phenomena and mechanisms of failure in patients with Fontan circulation-a surgically established circulation for patients born with a functionally single ventricle-remains challenging due to the complex hemodynamics and high interpatient variations in anatomy and function. In this work, we present a biomechanical model of the heart and circulation to augment the diagnostic evaluation of Fontan patients with early-stage heart failure. The proposed framework employs a reduced-order model of heart coupled with a simplified circulation including venous return, creating a closed-loop system. We deploy this framework to augment the information from data obtained during combined cardiac catheterization and magnetic resonance exams (XMR), performed at rest and during dobutamine stress in 9 children with Fontan circulation and 2 biventricular controls. We demonstrate that our modeling framework enables patient-specific investigation of myocardial stiffness, contractility at rest, contractile reserve during stress and changes in vascular resistance. Hereby, the model allows to identify key factors underlying the pathophysiological response to stress in these patients. In addition, the rapid personalization of the model to patient data and fast simulation of cardiac cycles make our framework directly applicable in a clinical workflow. We conclude that the proposed modeling framework is a valuable addition to the current clinical diagnostic XMR exam that helps to explain patient-specific stress hemodynamics and can identify potential mechanisms of failure in patients with Fontan circulation.

Investigating the causes of failure of Fontan circulation in individual patients remains challenging despite detailed combined invasive cardiac catheterisation and magnetic resonance (XMR) exams at rest and during stress. In this work, we use a biomechanical model of the heart and Fontan circulation with the components of systemic and pulmonary beds to augment the diagnostic assessment of the patients undergoing the XMR stress exam. We apply our model in 3 Fontan patients and one biventricular "control" case. In all subjects, we obtained important biophysical factors of cardiovascular physiology-contractility, contractile reserve and changes in systemic and pulmonary vascular resistance-which contribute to explaining the mechanism of failure in individual patients. Finally, we used the patient-specific model of one Fontan patient to investigate the impact of changes in pulmonary vascular resistance, aiming at in silico testing of pulmonary vasodilation treatments.

Background Percutaneous endoscopic gastrostomy (PEG) is an important route of nutrition in many patients. PEG removal usually leads to spontaneous closure in a few days. Gastrocutaneous fistula (GCF) after PEG removal is an uncommon complication occurring in 2% of patients. Despite its rarity, it is responsible for significant morbidity and reduced quality of life. Treatment is initially focused on medical management and endoscopic clipping, with advanced endoscopic techniques and surgery reserved for selected cases. Method We present a video presentation demonstrating successful endoscopic treatment of GCF using the OVESCO Over the Scope clip with resolution of symptoms and closure of the fistula tract. The device is a novel innovation designed to achieve tissue apposition and compression without ischaemia. It is licensed for Gastrointestinal iatrogenic defects, endoscopic perforation, bleeding and GCF. The 72 year old patient had debilitating symptoms of gastric leakage for over a year despite previous attempts at endoscopic clipping, fibrin glue and curettage of the fistula tract. Results As shown in the video, the clip achieved good opposition with no post procedural leak. The patient was reviewed at 3 and 12 months with no recurrence of their symptoms. The external cutaneous opening had closed at 3 months. The patient reported an increase in weight, improved mood and a greater quality of life following the intervention. Conclusion The OVESCO clip has been proven to facilitate successful endoscopic closure of GCF in selected patients in whom initial treatment measures have failed. This mitigates the need and risks of surgical closure.