CRIMSON: An open-source software framework for cardiovascular integrated modelling and simulation.

In this work, we describe the CRIMSON (CardiovasculaR Integrated Modelling and SimulatiON) software environment. CRIMSON provides a powerful, customizable and user-friendly system for performing three-dimensional and reduced-order computational haemodynamics studies via a pipeline which involves: 1) segmenting vascular structures from medical images; 2) constructing analytic arterial and venous geometric models; 3) performing finite element mesh generation; 4) designing, and 5) applying boundary conditions; 6) running incompressible Navier-Stokes simulations of blood flow with fluid-structure interaction capabilities; and 7) post-processing and visualizing the results, including velocity, pressure and wall shear stress fields. A key aim of CRIMSON is to create a software environment that makes powerful computational haemodynamics tools accessible to a wide audience, including clinicians and students, both within our research laboratories and throughout the community. The overall philosophy is to leverage best-in-class open source standards for medical image processing, parallel flow computation, geometric solid modelling, data assimilation, and mesh generation. It is actively used by researchers in Europe, North and South America, Asia, and Australia. It has been applied to numerous clinical problems; we illustrate applications of CRIMSON to real-world problems using examples ranging from pre-operative surgical planning to medical device design optimization.

An unusual case of clavicular prosthesis migration causing traumatic injury to the ascending aorta.

Traumatic aortic injuries can be a lethal event. Almost 88% of patients with traumatic aortic injuries die within the first hour and only 2% survive long enough to develop a chronic aneurysm. Injury to the ascending aorta, whether acute or chronic, are typically managed with surgery, and those in the descending aorta, are managed conservatively or in some cases with stents. We present a rare case of a 53-year old gentleman with intra-aortic migration of a left clavicular prosthesis used for restoration of the left shoulder girdle.

Neo-annulus: a reference plane in a surgical heart valve to facilitate a valve-in-valve procedure.

OBJECTIVES: To determine the level of the narrowest plane (neo-annulus) of a surgical heart valve (SHV), which could be used for sizing and securing a transcatheter heart valve (THV) during a valve-in-valve (VIV) procedure and define its relationship with the fluoroscopic markers of the SHV. BACKGROUND: In the native aortic valve, the aortic annulus is used as a reference plane for sizing and deployment of THV as it provides the narrowest dimension to securely anchor the THV. However, the reference level for different models of SHV that are currently treated by a VIV procedure remains unknown. METHODS: We studied 13 aortic SHVs from all major heart valve manufacturers (labeled size 21, 22, or 23). A 26cc valvuloplasty balloon was inflated with contrast within each SHV under fluoroscopy to achieve a 'waist'. The level of the 'waist' was compared with the SHV and its fluoroscopic markers to identify the level of the neo-annulus. RESULTS: In all SHVs tested, the balloon 'waist' or 'neo-annulus' was at the level of the sewing ring. When the fluoroscopic marker of the SHV was the sewing ring, the level of the neo-annulus was also at that level, irrespective of supra-annular or intra-annular design. However, when the fluoroscopic marker was the stent frame, the relationship between the fluoroscopic marker and the level of the neo-annulus was different for supra-annular and intra-annular designs. This correlation was not possible in two models of SHV as neither the stent nor the sewing ring was radio-opaque. CONCLUSIONS: We have demonstrated that the narrowest portion of all SHVs is at the level of its sewing ring, which can be identified fluoroscopically and should be used as a reference level during a VIV procedure.

Management of pneumothorax in mechanically ventilated COVID-19 patients: early experience.

A significant proportion of patients infected with the novel coronavirus, now termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), require intensive care admission and subsequent mechanical ventilation. Pneumothorax, a potential fatal complication of mechanical ventilation, can further complicate the management of COVID-19 patients, whilst chest drain insertion may increase the risk of transmission of attending staff. We present a case series and a suggested best-practice protocol for how to manage and treat pneumothoraces in COVID-19 patients in an intensive care unit setting.

Transhiatal esophagectomy in a high volume institution.

BACKGROUND: The optimal operative approach for carcinoma at the lower esophagus and esophagogastric junction remains controversial. The aim of this study was to assess a single unit experience of transhiatal esophagectomy in an era when the use of systemic oncological therapies has increased dramatically. STUDY DESIGN: Between January 2000 and November 2006, 215 consecutive patients (182 males, 33 females, median age = 65 years) underwent transhiatal esophagectomy; invasive malignancy was detected preoperatively in 188 patients. 90 patients (42%) received neoadjuvant chemotherapy. Prospective data was obtained for these patients and cross-referenced with cancer registry survival data. RESULTS: There were 2 in-hospital deaths (0.9%). Major complications included: respiratory complications in 65 patients (30%), cardiovascular complications in 31 patients (14%) and clinically apparent anastomotic leak in 12 patients (6%). Median length of hospital stay was 14 days. The radicality of resection was inversely related to T stage: an R0 resection was achieved in 98-100% of T0/1 tumors and only 14% of T4 tumors. With a median follow up of 26 months, one and five year survival rates were estimated at 81% and 48% respectively. CONCLUSION: Transhiatal esophagectomy is an effective operative approach for tumors of the infracarinal esophagus and the esophagogastric junction. It is associated with low mortality and morbidity and a five survival rate of nearly 50% when combined with neoadjuvant chemotherapy.

Paraneoplastic cerebellar degeneration as a presentation of breast cancer - a case report and review of the literature.

Paraneoplastic cerebellar degeneration is part of a rare spectrum of neurological syndromes whereby gynaecological, lung or breast cancers present primarily with neurological manifestations. The presence of onconeural antibodies and PET scanning help in the challenging diagnosis of these conditions but despite the treatment of the primary cancer, the prognosis for the neurological symptoms is poor.

Multi-modality image-based computational analysis of haemodynamics in aortic dissection.

Aortic dissection is a disease whereby an injury in the wall of the aorta leads to the creation of a true lumen and a false lumen separated by an intimal flap which may contain multiple communicating tears between the lumina. It has a high associated morbidity and mortality, but at present, the timing of surgical intervention for stable type B dissections remains an area of debate. Detailed knowledge of haemodynamics may yield greater insight into the long-term outcomes for dissection patients by providing a greater understanding of pressures, wall shear stress and velocities in and around the dissection. In this paper, we aim to gather further insight into the complex haemodynamics in aortic dissection using medical imaging and computational fluid dynamics modelling. Towards this end, several computer models of the aorta of a patient presenting with an acute Stanford type B dissection were created whereby morphometric parameters related to the dissection septum were altered, such as removal of the septum, and the variation of the number of connecting tears between the lumina. Patient-specific flow data acquired using 2D PC-MRI in the ascending aorta were used to set the inflow boundary condition. Coupled zero-dimensional (Windkessel) models representing the distal vasculature were used to define the outlet boundary conditions and tuned to match 2D PC-MRI flow data acquired in the descending aorta. Haemodynamics in the dissected aorta were compared to those in an equivalent 'healthy aorta', created by virtually removing the intimal flap (septum). Local regions of increased velocity, pressure, wall shear stress and alterations in flow distribution were noted, particularly in the narrow true lumen and around the primary entry tear. The computed flow patterns compared favourably with those obtained using 4D PC-MRI. A lumped-parameter heart model was subsequently used to show that in this case there was an estimated 14 % increase in left ventricular stroke work with the onset of dissection. Finally, the effect of secondary connecting tears (i.e. those excluding the primary entry and exit tears) was also studied, revealing significant haemodynamic changes when no secondary tears are included in the model, particularly in the true lumen where increases in flow over [Formula: see text] and drops in peak pressure of 18 % were observed.

Valve-in-Valve Therapy for Failed Surgical Bioprosthetic Valves: Clinical Results and Procedural Guidance.

With improved life expectancy and increased use of bioprosthetic heart valves, more elderly and frail patients present with degenerative surgical heart valve disease. The valve-in-valve procedure is an attractive alternative to a conventional open redo procedure. Although it is a novel extension of established transcatheter aortic valve implantation for severe aortic stenosis in a high-risk population, it is gaining momentum worldwide, particularly for aortic and mitral positions. Success depends on the operator being familiar with emerging transcatheter heart valve technology and morphology as well as that of the existing surgical heart valve, patient selection, accurate sizing, an ideal implantation position.

Challenges in valve-in-valve therapy.

At present, the majority of surgical heart valves (SHVs) implanted are bioprosthetic valves. Over time however, these are prone to structural deterioration, which may manifest as valvular stenosis, regurgitation or a combination of the two. Re-operation is the current standard of care for these patients but this itself carries a significant risk of mortality and morbidity. As a natural extension of transcatheter aortic valve implantation (TAVI), now an evidence based solution for severe aortic stenosis in high-risk patients, valve-in-valve (VIV) therapy is evolving into an alternative option in selected patients with structural biological valvular deterioration in all four-valve positions. The first of these VIV procedures was performed in Germany in 2007, for failing aortic valve prosthesis and later, reported in other positions. As with any novel emerging therapy, there is a learning curve to the procedure and the operator must be aware of the potential challenges. In this review we describe some of these challenges with the aim of providing awareness as well as guidance on attaining a successful outcome.

Differences in Outcomes and Indications between Sapien and CoreValve Transcatheter Aortic Valve Implantation Prostheses.

Transcatheter aortic valve implantation (TAVI) has emerged as a suitable alternative to surgical valve replacement for patients with severe, symptomatic, calcified aortic stenosis and a background of co-morbidities, which can make surgery a high-risk option. It has also evolved as an alternative for degenerative prosthetic heart valve disease. Since the inception of TAVI in 2002, the two main devices in routine clinical use are the Edwards Sapien valve (since 2006) and the Medtronic CoreValve (since 2007). The more recent Sapien XT valve and Sapien 3 have been in clinical use since 2010 and 2013, respectively. In addition to registry data on these devices, there are a number of completed and ongoing randomised controlled trials, including one comparing the two devices. The aim of this article is to discuss the differences in indications and outcomes between these two prostheses.

Valve-in-valve procedure: importance of the anatomy of surgical bioprostheses.

Transcatheter aortic valve implantation is an accepted and established alternative to surgical aortic valve replacement for patients with severe symptomatic aortic valve stenosis and multiple comorbidities that would make open surgery a high-risk option. It has also evolved as a suitable treatment option for degenerative surgical heart valve disease, with considerable experience in the aortic and mitral positions. To enable a successful procedure, avoiding malposition, valve embolization and coronary obstruction, clinicians should be familiar with the design, fluoroscopic appearances and implantation technique of the degenerated surgical bioprosthetic valve in situ, as well as its compatibility with currently available transcatheter valves.

Post-infarction biventricular free wall rupture with extracardiac shunt presenting as ventricular septal rupture.

Ventricular free wall rupture is a rare, usually fatal complication of acute myocardial infarction. Subacute free wall rupture with pseudoaneurysm formation is even rarer, but may be associated with a chance of survival if surgery is performed expeditiously. Although rupture of the left ventricle is more common, right-sided rupture has also been reported. We report an unusual case of post-infarct biventricular rupture masquerading as a ventricular septal defect, due to an extracardiac shunt within the pseudoaneurysm. Our patient underwent urgent surgery, made an excellent recovery and was discharged home in a fully functional condition within a week post-surgery.

Haemoptysis from a Dacron graft aneurysm 21 years post repair of coarctation of the aorta.

We report an unusual complication of a Dacron graft in a 31-year-old woman who had undergone extra-anatomical bypass for coarctation of the aorta aged 11 years. She presented with haemoptysis, and imaging confirmed an aneurysm of the Dacron graft at the proximal anastomosis with the aorta, eroding into the right upper lobe, as well as a smaller aneurysm at the anastomosis with the descending aorta. She underwent a median sternotomy and refashioning of the bypass, and a re-do right thoracotomy with removal of the Dacron graft and a right upper and middle lobectomy.