Bayesian networks identify determinants of outcomes following cardiac surgery in a UK population.

BACKGROUND: Traditional risk stratification tools do not describe the complex principle determinant relationships that exist amongst pre-operative and peri-operative factors and their influence on cardiac surgical outcomes. This paper reports on the use of Bayesian networks to investigate such outcomes. METHODS: Data were prospectively collected from 4776 adult patients undergoing cardiac surgery at a single UK institute between April 2012 and May 2019. Machine learning techniques were used to construct Bayesian networks for four key short-term outcomes including death, stroke and renal failure. RESULTS: Duration of operation was the most important determinant of death irrespective of EuroSCORE. Duration of cardiopulmonary bypass was the most important determinant of re-operation for bleeding. EuroSCORE was predictive of new renal replacement therapy but not mortality. CONCLUSIONS: Machine-learning algorithms have allowed us to analyse the significance of dynamic processes that occur between pre-operative and peri-operative elements. Length of procedure and duration of cardiopulmonary bypass predicted mortality and morbidity in patients undergoing cardiac surgery in the UK. Bayesian networks can be used to explore potential principle determinant mechanisms underlying outcomes and be used to help develop future risk models.

Infected mediastinal cysts following endobronchial ultrasound guided biopsy-a case series.

Mediastinal cysts are commonly an incidental finding simulating a benign or malignant diagnosis. Infection is a recognised complication of mediastinal cyst and therefore early surgical management is essential. Endobronchial ultrasound guided biopsy (EBUS) has been used to diagnose and manage mediastinal cyst. We present a case series of three patients who presented with sepsis following diagnostic EBUS of mediastinal cyst. We would recommend that EBUS guided biopsy be applied cautiously if there is a high suspicion of mediastinal cyst to avoid post procedural infection, which can thus complicate any future therapeutic options.

Aortic valve surgery for native valve endocarditis in extreme obesity.

Surgical aortic valve replacement represents a class one indication in the setting of aortic valve endocarditis and decompensated heart failure secondary to aortic regurgitation as per the European Society of Cardiology. However, extreme obesity, whereby the body mass index (BMI) >40 kg/m2, represents a challenging cohort of patients. Performing cardiac surgery in the bariatric population is fraught with challenges pertaining to intraoperative issues of surgical access and approach. We describe the case of a 45-year-old gentleman who had previous been diagnosed with infective endocarditis of the aortic valve and with a BMI of 68.2 (228 kg). Surgical aortic valve replacement in extreme obesity is associated with deep sternal wound infection, requirement and duration of mechanical ventilation, atrial fibrillation and renal failure. The 'obesity paradox' of overweight and class I obesity (BMI <35) has demonstrated favourable long-term results compared with underweight patients or even those with normal BMI undergoing cardiac surgery.

Triplegic Stroke After Air Embolism From Bronchogenic Cyst Secondary to Barotrauma.

Emergency medical assistance is rare regarding air travel. Pulmonary barotrauma during air travel can occur in asymptomatic patients who have underlying intraparenchymal pulmonary pathology such as bullae or bronchogenic cysts. During aircraft travel the resultant decrease in pressure during the ascent can lead to expansion of cyst volume, culminating in tears and leakage of air into the surrounding vasculature and thus the potential for air embolism. We describe a case of massive cerebral air embolism secondary to pulmonary barotrauma in a previously asymptomatic patient.

Anterior leaflet replacement and reconstruction with Admedus Cardiocel™ decellularized pericardial patch in tricuspid valve endocarditis.

We present the case of a 28 year-old lady with a history of intravenous drug use who presented to our institution with symptomatic right heart failure secondary to tricuspid valve regurgitation. She presented with infective endocarditis leading to dyspnoea and peripheral oedema secondary to torrential tricuspid regurgitation. Transthoracic echocardiography confirmed right ventricular dysfunction and congestive hepatomegaly. Intra-operatively findings an infected and destroyed anterior leaflet of the tricuspid valve with posterior leaflet prolapse was found to cause severe tricuspid regurgitation. She had complex tricuspid valve reconstruction using anterior leaflet reconstruction using Admedus Cardiocel™ patch, posterior leaflet prolapse correction and commissural reduction with a McGoon imbrication and annuloplasty ring to stabilize the repair. This case demonstrates the importance of reconstructive tricuspid valve surgery in the setting of infective endocarditis. Furthermore, this case demonstrates the possibility of anterior leaflet excision and reconstruction with an excellent durable functional result.

Delayed chylothorax in the absence of radiological evidence of rib or vertebral body fractures following blunt trauma.

Our case report illustrates effective implementation of conservative measures without the need for more invasive procedures, which can be required in refractory cases. Our patient was a 42-year-old female who fell from a horse and presented with a 1-week history of dyspnoea. Investigations revealed her to have a large right chylothorax, which was treated conservatively with chest drainage and octreotide. The patient remained in hospital for a total of 3 days prior to being discharged home without further complications. Blunt traumatic chylothorax should be considered as part of the differential diagnosis in patients who present with ongoing dyspnoea or chest discomfort within a 2-week preceding history of blunt trauma. Radiological imaging should be mandatory and the absence of posterior thoracic fractures does not exclude the diagnosis. Conservative management with pleural drainage, medium-chain triglyceride diet and octreotide yielded excellent results in our case.

Minimising risk to thoracic surgical teams in an era of COVID-19: exploring possible preventative measures.

The demands of curtailing the impact of the coronavirus disease 2019 (COVID-19) global pandemic have disrupted the world's ability to care for patients with thoracic pathologies. Those who undergo thoracic surgical therapeutic procedures are a high-risk category, likely to have impaired lung function but also high risk for exposing clinical teams to aerosolised viral loads. In light of this global pandemic, thorough pre-procedural planning, adequate personal protective equipment (PPE), experienced personnel and judicious anaesthetic and intra-operative measures will serve to be instrumental in ensuring positive patient outcomes whilst still protecting the safety of healthcare workers.

Pulmonary lymphangioleiomyomatosis masquerading as unilateral heterogeneous emphysema.

Pulmonary lymphangioleiomyomatosis (LAM) is a rare, well-described pathology and usually is exclusive to females of a reproductive age. We present a 45 year-old lady who presented to the surgeons 1 year after an admission with acute dyspnoea following influenza infection. Initial computed tomography imaging findings demonstrated severe, heterogenous right-sided bullous emphysematous changes, but histopathological analysis of the post-operative specimen favoured a diagnosis of LAM. This case demonstrates the importance of considering LAM as a differential diagnosis for findings of unilateral emphysema or lobar emphysema, in which alpha 1-antitrypsin deficiency has been excluded and in those without a significant smoking history.

A combined approach to correct posterior left ventricular aneurysm, aortic stenosis and coronary artery disease.

Ischaemic heart disease and aortic stenosis are potentially life-threatening conditions. A post-infarct left ventricular aneurysm, when combined with the above, is particularly hazardous. We present a case where all three conditions occurred simultaneously and describe the surgical approach undertaken to attempt correction. The patient underwent aneurysmectomy together with aortic valve replacement and two-vessel coronary artery bypass grafting. The aneurysm was excised with direct linear closure of the walls using a Teflon-buttressed interrupted mattress suture technique. Post-operatively, ventricular systolic function was good (LVEF 40%) together with a well-seated aortic valve showing no paravalvular leaks. This case highlights the importance of meticulous removal of thrombus from the aneurysm and everting the edges thereby eliminating a thrombogenic surface and the risk of embolic stroke. The restorative procedure itself serves to underline the importance of ventricular shape in the effective functioning of the myocardium for sustaining an adequate stroke volume with normalized physiology.

Excision of metastatic breast cancer from sternum and reconstruction in two patients with solitary metastatic spread.

Metastatic breast carcinoma is a relatively common clinical entity. However, the prognosis of oligometastatic and polygometastatic disease differs considerably pertaining to five-year survival. Metastatic breast carcinoma to the sternum has been described as early as 1988. We describe two cases in our institution who presented with solitary sternal metastases with a previous history of treated breast cancer. In both cases, there had been a history of previous left breast cancer treated aggressively with surgical resection and adjuvant oncological therapy and maintenance hormonal therapy. Partial sternectomy or total sternectomy for solitary metastatic sternal deposits is well established with relatively low morbidity and mortality and improvement in quality of life and possible improvement in long-term survival. Furthermore, reconstructive options are inherently dependent on extent of resection performed. These techniques can incorporate the use of sternal plates in order to approximate defects and reinforce the sternum in the setting of partial sternectomy.

Delayed presentation of a traumatic descending thoracic aorta aneurysm as an aorto-oesophageal fistula.

Aorto-oesophageal fistula is a rarely described but life-threatening complication presenting with upper gastrointestinal haemorrhage. We present a case of a 58-year-old gentleman who presented to a peripheral hospital with a short duration of haematemesis and melaena and recent onset symptoms of dysphagia. This gentleman had a past medical history of alcohol excess and a history of trauma following a road traffic accident 38 years ago. Initial computer tomography scan demonstrated a large saccular aneurysm arising from the descending thoracic aorta adjacent to the oesophagus. The patient underwent radiological stenting of the large aneurysm with thoracic endovascular aortic replacement procedure. Follow-up computerized tomography (CT) angiography demonstrated satisfactory appearances of the thoracic aortic stent graft with no evidence of endo-leak. The triad of dysphagia, occult gastrointestinal blood loss and CT findings of a large aneurysm should prompt diagnosis or aorto-oesophageal fistula until proven otherwise.

Aspergillus-related lung mass masquerading as a lung tumour.

Aspergillus is a common environmental pathogen. However, clinically significant disease only occurs in a small proportion of patients. Although rare in its occurrence, it remains a considerable cause of morbidity and mortality in certain cohorts of patients. We describe a rare case of Aspergillus disease masquerading as a primary lung malignancy. Computer tomography pulmonary angiogram scan demonstrated a right upper lobe 8 x 6.5 cm soft-tissue lesion. Positron emission tomography CT demonstrated this lesion to be intensely fluorodeoxyglucose avid. Initial bronchoscopy demonstrated occluded subsegmental right upper lobe bronchus with white friable material. Follow-up bronchoscopy demonstrated evidence of a previous inflammatory process with cavitation and destruction of sub-lobar bronchial tree. Serial chest radiographs demonstrated almost complete resolution of the right upper lobe mass. Thus, this presentation of an Aspergillus-related lung mass masquerading as a primary lung malignancy provided several important learning points pertaining to diagnosis and ensuing management.

Pneumatic-aorta: an unusual aetiology for stroke.

The following report describes a case in which air in the aorta led to stroke from cerebral emboli in a patient with distal oesophageal cancer. The patient presented with clinical features of a right-sided stroke. Computed tomography scans revealed air in the ascending aorta and brachiocephalic artery as a result of an oesophago-atrial fistula. The patient deteriorated and died soon after hospital admission despite conservative measures successfully dissipating the air. When encountered, emergent treatment of the underlying cause should be addressed but the outcome remains poor.

Synchronous primary lung and breast carcinoma removed via a single incision.

We describe a case of a middle-aged female who was diagnosed with synchronous primary lung and breast cancer following a bout of recurrent chest infections. Subsequent Multi Disciplinary Team (MDT) discussion proposed that in light of the patients' multiple comorbidities, both lesions should be resected simultaneously under one general anaesthetic. The patient underwent an initial left mastectomy and axillary node clearance. Through the same incision, a left anterolateral thoracotomy was created to complete a left lower lobectomy. Post-operatively she made an uncomplicated recovery and was discharged 7 days after the procedure. Despite undergoing a longer and more complex procedure, her length of stay was in keeping with the average length of stay for a patient undergoing a thoracotomy and lobectomy [1]. This case highlights the importance of a pre-planned multidisciplinary approach to deal with synchronous pathology in an efficiently synchronous manner to improve patient outcomes.

Test performance of PET-CT for mediastinal lymph node staging of pulmonary carcinoid tumours.

Positron emission tomography-CT (PET-CT) is one of the initial mediastinal staging modality for non-small cell lung cancer; however, the clinical utility in carcinoid tumours is uncertain. We sought to determine the test performance of PET-CT for mediastinal lymph node staging of pulmonary carcinoid tumours. We collated data from seven institutions, performing a retrospective search on pathological databases for a consecutive series of patients who underwent thoracic surgery (with lymph nodal dissection) for carcinoid tumours with preoperative PET-CT staging. PET-CT results were compared with the reference standard of pathologic results obtained from lymph node dissection and test performance reported using sensitivity and specificity. From November 1999 to January 2013, 247 patients from seven institutions underwent surgery for carcinoid tumours with a corresponding preoperative PET-CT scan. The mean age of the patients was 61 (SD 15, range 73) and 84 were male patients (34%). The pathologic subtype was typical carcinoid in 217 patients (88%) and atypical carcinoid in 30 patients (12%). Results from lymph node dissection were obtained in 207 patients. The calculated sensitivity and specificity of PET-CT to identify mediastinal lymph node disease was 33% (95% CI 4% to 78%) and 94% (95% CI 89% to 97%), respectively. Our results indicate that PET-CT has a poor sensitivity but good specificity to detect the presence of mediastinal lymph node metastases in pulmonary carcinoid tumours. Mediastinal lymph node metastases cannot be ruled out with negative PET-CT uptake, and if the absence of mediastinal lymph node disease is a prerequisite for directing management, tissue sampling should be undertaken.

Extended extraocular phenotype of PROM1 mutation in kindreds with known autosomal dominant macular dystrophy.

Mutations in prominin 1 (PROM1) have been shown to result in retinitis pigmentosa, macular degeneration and cone-rod dystrophy. Because of the putative role of PROM1 in hippocampal neurogenesis, we examined two kindreds with the same R373C PROM1 missense mutation using our established paradigm to study brain structure and function. As the protein encoded by PROM1, known as CD133, is used to identify stem/progenitor cells that can be found in peripheral blood and reflect endothelial reparatory mechanisms, other parameters were subsequently examined that included measures of vascular function, endothelial function and angiogenic capacity. We found that aspects of endothelial function assayed ex vivo were abnormal in patients with the R373C PROM1 mutation, with impaired adhesion capacity and higher levels of cellular damage. We also noted renal infections, haematuria and recurrent miscarriages possibly reflecting consequences of abnormal tubular modelling. Further studies are needed to confirm these findings.