Decreasing the blood flow of non-compressible intra-abdominal organs with non-invasive transcutaneous electrical stimulation.

Non-invasive neuromodulation of non-compressible internal organs has significant potential for internal organ bleeding and blood-shift in aero/space medicine. The present study aims to investigate the potential influences of the non-invasive transcutaneous electrical nerve stimulation (TENS) on multiple non-compressible internal organs' blood flow. Porcine animal model (n = 8) was randomized for a total of 48 neuromodulation sessions with two different TENS stimulation frequencies (80 Hz, 10 Hz) and a placebo stimulation. A combination of two different electrode configurations (Abdominal-only or Abdominal and hind limb) were also performed. Intraarterial blood flow measurements were taken during pre and post-stimulation periods at the left renal artery, common hepatic artery, and left coronary artery. Intracranial, and extracranial arterial blood flows were also assessed with digital subtraction angiography. TENS with abdominal-only electrode configurations at 10 Hz demonstrated significant reductions in average peak blood flow velocity (APV) of the common hepatic artery (p = 0.0233) and renal arteries (p = 0.0493). Arterial pressures (p = 0.0221) were also significantly lower when renal APV was reduced. The outcome of the present study emphasises the potential use of TENS in decreasing the blood flow of non-compressible internal organs when the correct combination of electrodes configuration and frequency is used.

Surgical outcomes and cost analysis of a multi-specialty robotic-assisted surgery caseload in the Australian public health system.

This study aims to compare surgical outcomes and in-hospital cost between robotic-assisted surgery (RAS), laparoscopic and open approaches for benign gynaecology, colorectal and urological patients and to explore the association between cost and surgical complexity. This retrospective cohort study included consecutive patients undergoing RAS, laparoscopic or open surgery for benign gynaecology, colorectal or urological conditions between July 2018 and June 2021 at a major public hospital in Sydney. Patients' characteristics, surgical outcomes and in-hospital cost variables were extracted from the hospital medical records using routinely collected diagnosis-related groups (DRG) codes. Comparison of the outcomes within each surgical discipline and according to surgical complexity were performed using non-parametric statistics. Of the 1,271 patients included, 756 underwent benign gynaecology (54 robotic, 652 laparoscopic, 50 open), 233 colorectal (49 robotic, 123 laparoscopic, 61 open) and 282 urological surgeries (184 robotic, 12 laparoscopic, 86 open). Patients undergoing minimally invasive surgery (robotic or laparoscopic) presented with a significantly shorter length of hospital stay when compared to open surgical approach (P < 0.001). Rates of postoperative morbidity were significantly lower in robotic colorectal and urological procedures when compared to laparoscopic and open approaches. The total in-hospital cost of robotic benign gynaecology, colorectal and urological surgeries were significantly higher than other surgical approaches, independent of the surgical complexity. RAS resulted in better surgical outcomes, especially when compared to open surgery in patients presenting with benign gynaecology, colorectal and urological diseases. However, the total cost of RAS was higher than laparoscopic and open surgical approaches.

Synchronous Carotid Endarterectomy and Anaortic Off-Pump Coronary Artery Bypass Surgery.

BACKGROUND: There is ongoing debate regarding the optimal strategy and timing for the surgical management of patients with severe concomitant carotid and coronary artery disease. Anaortic off-pump coronary artery bypass (anOPCAB), which avoids aortic manipulation and cardiopulmonary bypass, has been shown to reduce the risk of perioperative stroke. We present the outcomes of a series of synchronous carotid endarterectomy (CEA) and anOPCAB. METHODS: A retrospective review was performed. The primary endpoint was stroke at 30 days post-operation. Secondary endpoints included transient ischaemic attack, myocardial infarction and mortality 30 days post-operation. RESULTS: From 2009 to 2016, 1,041 patients underwent anOPCAB with a 30-day stroke rate of 0.4%. The majority of patients had preoperative carotid-subclavian duplex ultrasound screening and 39 were identified with significant concomitant carotid disease who underwent synchronous CEA-anOPCAB. The mean age was 71±7.5 years. Nine patients (23.1%) had previous neurological events. Thirty (30) patients (76.9%) underwent an urgent operation. For CEA, a conventional longitudinal carotid endarterectomy with patch angioplasty was performed in all patients. For anOPCAB, total arterial revascularisation rate was performed in 84.6% and the mean number of distal anastomoses was 2.9±0.7. In the 30-day postoperative period, there was one stroke (2.63%), two deaths (5.26%), two transient ischaemic attacks (TIAs) (5.26%) and no myocardial infarction. Two patients experienced acute kidney injury (5.26%), one of which required haemodialysis (2.63%). Mean length of stay was 11.37±7.9 days. CONCLUSION: Synchronous CEA and anOPCAB is a safe and effective option for patients' severe concomitant disease. Preoperative carotid-subclavian ultrasound screening allows identification of these patients.

Outcomes Following Triple Cardiac Valve Surgery Over 17-years: A Multicentre Population-Linkage Study.

INTRODUCTION: Studies have reported increasing triple valve surgery (TVS, defined as concomitant aortic, mitral and tricuspid valves surgery) incidence and improved postoperative survival. The epidemiology and outcome of TVS is not known in Australia. METHODS: From the Admission-Patient-Data-Collection registry, all New South Wales residents who underwent cardiac valve surgery between 1 July 2001 and 31 December 2018 were identified, with cause-specific mortality tracked from the death registry. RESULTS: Triple valve surgery comprised 1.2% (347/28,667 cases) of all valvular surgeries. Volumes rose from eight cases-per-annum in 2002 to a peak of 37 in 2012, and between 23 and 30 cases-per-annum since. Mean (±SD) age of study cohort (n=340 persons) was 68.2±15.2 years (50% male); 20.3% had concomitant coronary-artery-bypass-surgery (males vs females: 29.4% vs 11.2%, p<0.001). Main surgery on aortic and mitral valves was replacement (95.9% and 70.6% respectively). Tricuspid valve annuloplasty was performed in 90.6% of patients. Cumulative in-hospital, 180-day, and total mortality (mean follow-up=4.9±4.0 yrs) was 7.4%, 11.8% and 42.6%, respectively. Heart failure (24.0% in-hospital, 22.5% post-discharge) and sepsis (24.0% in-hospital, 20.0% post-discharge) were the main cause-specific deaths. There was no in-hospital stroke-related death. Age (median >72 yrs; hazard ratio [HR]=1.95, 95%CI=1.37-2.79), malignancy (HR=6.35, 95%CI=2.21-18.26), heart failure (HR=1.79, 95%CI=1.25-2.57) and chronic kidney disease (CKD) (HR=2.21, 95%CI=1.39-3.51) (all p<0.005) were independent predictors during intermediate-term follow-up. CONCLUSIONS: Triple valve surgery remains rare in Australia and is associated with high mortality. Multi-centred collaboration and access to comprehensive clinical data are required to identify the drivers of poor outcome.

Splitting the anterior mitral leaflet impairs left ventricular function in an ovine model.

OBJECTIVES: During mitral valve replacement, the anterior mitral leaflet is usually resected or modified. Anterior leaflet splitting seems the least disruptive modification. Reattachment of the modified leaflet to the annulus reduces the annulopapillary distance. The goal of this study was to quantify the acute effects on left ventricular function of splitting the anterior mitral leaflet and shortening the annulopapillary distance. METHODS: In 6 adult sheep, a wire was placed around the anterior leaflet and exteriorized through the left ventricular wall to enable splitting the leaflet in the beating heart. Releasable snares to reduce annulopapillary distance were likewise positioned and exteriorized. A mechanical mitral prosthesis was inserted to prevent mitral incompetence during external manipulations of the native valve. Instantaneous changes in left ventricular function were recorded before and after shortening the annulopapillary distance, then before and after splitting the anterior leaflet. RESULTS: After splitting the anterior leaflet, preload recruitable stroke work, stroke work, stroke volume, cardiac output, left ventricular end systolic pressure and mean pressure were significantly decreased by 26%, 23%, 12%, 9%, 15% and 11%, respectively. Shortening the annulopapillary distance was associated with significant decreases in the end systolic pressure volume relationship, preload recruitable stroke work, stroke work and left ventricular end systolic pressure by 67%, 33%, 15% and 13%, respectively. Shortening the annulopapillary distance after splitting the leaflet had no significant effect. CONCLUSIONS: Splitting the anterior mitral leaflet acutely impaired left ventricular contractility and haemodynamics in an ovine model. Shortening the annulopapillary distance after leaflet splitting did not further impair left ventricular function.

Long-term outcomes in heritable thoracic aortic disease.

Heritable aortic aneurysm is an increasingly recognized cause of morbidity and mortality. Whilst Marfan syndrome (MFS) is well-known, the clinical presentation and prognosis of more newly described genetic syndromes is less familiar to clinicians. There is a particular lack of knowledge regarding clinical outcomes for non-syndromal heritable aortic disease. This study investigated the presentation, clinical course and survival of patients with syndromal [Loeys-Dietz, aneurysm-osteoarthritis, and aneurysm-cerebral arteriopathy (ACTA2) syndrome] and non-syndromal heritable aortic disease in comparison to MFS. The study group includes 536 individuals (283 Marfan, 176 non-syndromal heritable aortopathy, 36 aneurysm-osteoarthritis, 32 Loeys-Dietz, and 9 ACTA2 aneurysm) enrolled in a longitudinal clinical follow-up between 1990 and 2022. Age at diagnosis differed between groups: Marfan = 22.0 ± 16.6; Loeys-Dietz = 29.6 ± 21.5; aneurysm-osteoarthritis = 36.4 ± 18.8; ACTA2 aneurysm = 43.4 ± 18.6; non-syndromal heritable aortopathy = 47.2 ± 16.6 years (p < 0.001). Aortic dissection was the presenting event in 8% individuals with Marfan compared to 27% with non-syndromal heritable aortopathy and 34% with Loeys-Dietz syndrome (p < 0.01). Mean follow-up duration for the group was 16.4 years (range 0.2-30 years) and 74 individuals died during follow-up (Marfan = 52, Loeys-Dietz = 6, aneurysm-osteoarthritis = 4, ACTA2 aneurysm = 1, heritable non-syndromal aortopathy = 11). At 10 years follow-up, actuarial mean survivals were: aneurysm-osteoarthritis = 77.5 ± 10.4%; Loeys-Dietz = 90.0 ± 6.8%; Marfan = 94.6 ± 1.4%; heritable non-syndromal aortopathy = 95.9 ± 2.1% (NS). There were 60 aortic dissections (24 Type A, 36 Type B) during follow-up. At 10 years, survival free of dissection was comparable between groups: aneurysm-osteoarthritis = 90.7 ± 6.4%; Loeys-Dietz = 94.4 ± 5.4%; Marfan = 96.1 ± 1.2%; heritable non-syndromal aortopathy = 93.9 ± 2.3%, with similar findings at 20 years. Prophylactic aortic surgery was a first event during follow-up for 196 individuals (ACTA2 aneurysm = 3; aneurysm-osteoarthritis = 10; Loeys-Dietz = 19; Marfan = 119; heritable non-syndromal aortopathy = 45). A second surgical intervention was required in 45 individuals and a third intervention in 21 individuals. At 10 years follow-up, survival free of surgery differed between groups: aneurysm-osteoarthritis = 68.5 ± 10.1%; Loeys-Dietz = 40.8 ± 11.2%; Marfan = 75.5 ± 2.7%; heritable non-syndromal aortopathy = 63.8 ± 4.7% (p < 0.001). At 20 years follow-up mean survival free of surgery was: aneurysm-osteoarthritis = 26.6 ± 14.7%; Loeys-Dietz = 9.1 ± 8.2%; Marfan = 57.2 ± 3.4%; heritable non-syndromal aortopathy = 41.6 ± 8.2% (p < 0.001). Diagnosis of newer syndromic and non-syndromal heritable aortopathies is delayed compared to MFS, with associated complications of presentation with aortic dissection. Survival of individuals enrolled in follow-up surveillance is comparable between different genetic aortopathies, however aortic dissections still occur and need for surgical intervention is high.

Ventricular Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy (Analysis Spanning 60 Years Of Practice): AJC Expert Panel.

Surgical myectomy remains the time-honored primary treatment for hypertrophic cardiomyopathy patients with drug refractory limiting symptoms due to LV outflow obstruction. Based on >50 years experience, surgery reliably reverses disabling heart failure by permanently abolishing mechanical outflow impedance and mitral regurgitation, with normalization of LV pressures and preserved systolic function. A consortium of 10 international currently active myectomy centers report about 11,000 operations, increasing significantly in number over the most recent 15 years. Performed in experienced multidisciplinary institutions, perioperative mortality for myectomy has declined to 0.6%, becoming one of the safest currently performed open-heart procedures. Extended myectomy relieves symptoms in >90% of patients by ≥ 1 NYHA functional class, returning most to normal daily activity, and also with a long-term survival benefit; concomitant Cox-Maze procedure can reduce the number of atrial fibrillation episodes. Surgery, preferably performed in high volume clinical environments, continues to flourish as a guideline-based and preferred high benefit: low treatment risk option for adults and children with drug refractory disabling symptoms from obstruction, despite prior challenges: higher operative mortality/skepticism in 1960s/1970s; dual-chamber pacing in 1990s, alcohol ablation in 2000s, and now introduction of novel negative inotropic drugs potentially useful for symptom management.

Analogue Mean Systemic Filling Pressure: a New Volume Management Approach During Percutaneous Left Ventricular Assist Device Therapy.

The absence of an accepted gold standard to estimate volume status is an obstacle for optimal management of left ventricular assist devices (LVADs). The applicability of the analogue mean systemic filling pressure (Pmsa) as a surrogate of the mean circulatory pressure to estimate volume status for patients with LVADs has not been investigated. Variability of flows generated by the Impella CP, a temporary LVAD, should have no physiological impact on fluid status. This translational interventional ovine study demonstrated that Pmsa did not change with variable circulatory flows induced by a continuous flow LVAD (the average dynamic increase in Pmsa of 0.20 ± 0.95 mmHg from zero to maximal Impella flow was not significant (p = 0.68)), confirming applicability of the human Pmsa equation for an ovine LVAD model. The study opens new directions for future translational and human investigations of fluid management using Pmsa for patients with temporary LVADs.

Novel insights into bicuspid aortic valve (BAV) aortopathy: Long non-coding RNAs TUG1 and MIAT are differentially expressed in BAV ascending aortas.

BACKGROUND: Whilst a combination of genetically mediated vulnerability and hemodynamic insult is suspected to contribute to bicuspid aortic valve (BAV) aortopathy, the underlying pathophysiological mechanisms are poorly understood. METHODS: Utilizing RT-qPCR, we compared the expression of 28 potentially relevant long non-coding RNA (lncRNA) in aortic tissue from BAV patients undergoing aortic surgery for aortopathy, to healthy controls. Relative lncRNA expression was measured using ΔΔCT, with fold-change calculated as RQ=2-ΔΔCT. RESULTS: When comparing samples from BAV patients (n=29, males n=25; median age 58 years, Q1-Q3 51-65, maximum aortic dimension 50±5 mm) with healthy controls (n=7; males n=4, P=.12; median age 39 years, Q1-Q3 18-47, P=.001), there were two differentially expressed lncRNA: TUG1 expression was significantly lower in BAV aortic tissue (RQ 0.59, 95% CI 0.50-0.69, P=.02), whilst MIAT expression was significantly higher (RQ 2.87, 95% CI 1.96-4.20, P=.01). Sensitivity analysis including only patients with normal BAV function showed similar trends of differential expression of TUG1 (RQ 0.69, 95% CI 0.50-0.90, P=.29) and MIAT (RQ 2.55, 95% CI 1.21-5.36, P=.29) compared to controls. CONCLUSIONS: LncRNA TUG1 and MIAT are differentially expressed in BAV aortopathy compared to healthy controls, independent of BAV hemodynamics. Aberrant lncRNA expression may be involved in the pathogenesis of BAV aortopathy.

Aorto-cavitary fistula: a rare case of Enterobacter cloacae infective endocarditis complicated by aortic root abscess and fistula to the right ventricle.

Enterobacter cloacae are a rare cause of infective endocarditis (IE). We present an interesting case of a 51-year-old intravenous drug user with E. cloacae IE of a prosthetic aortic valve and a fistula into the right ventricle. He underwent surgical repair and 6 weeks of intravenous meropenem.

PROSE: Prospective Randomized Trial of the On-X Mechanical Prosthesis and the St Jude Medical Mechanical Prosthesis Evaluation: Part 2: Study results-prostheses, positions, and economic development.

Objectives: The Prospective Randomized On-X Mechanical Prosthesis Versus St Jude Medical Mechanical Prosthesis Evaluation (PROSE) trial purpose was to investigate whether a current-generation mechanical prosthesis (On-X; On-X Life Technologies/Artivion Inc) reduced the incidence of thromboembolic-related complications compared with a previous-generation mechanical prosthesis (St Jude Medical Mechanical Prosthesis; Abbott/St Jude Medical). This second report documents the valve-related complications by individual prostheses and by Western and Developing populations. Methods: The PROSE trial study was conducted in 28 worldwide centers and incorporated 855 subjects randomized between 2003 and 2016. The study enrollment was discontinued on August 31, 2016. The study protocol, and analyses of 10 demographic variables and 24 risk factors were published in detail in 2021. Results: The total patient population (N = 855) included patients receiving an On-X valve (n = 462) and a St Jude Medical valve (n = 393). The overall freedom evaluation showed no differences at 5 years between the prostheses for thromboembolism or for valve thrombosis. There were also no differences in mortality. There were several differences between Developing and Western populations. The freedom relations at 5 years for mortality favored Western over Developing populations. Valve thrombosis was differentiated by position and site: aortic < mitral (P = .007) and Western < Developing (P = .005). In the mitral position there were no cases in Western populations, whereas there were 8 in Developing populations (P = .217). Conclusions: The On-X valve and St Jude Medical valve performed equally well in the study with no differences found. The only differentiation occurred with valve thrombosis in the mitral position more than the aortic position and occurring in Developing more than Western populations. The occurrence of valve thrombosis was also related to a younger population possibly due to anticoagulation compliance based on record review.

Post-operative outcomes of inflammatory thoracic aortitis: a study of 41 patients from a cohort of 1119 surgical cases.

Aortitis is found in 2-12% of thoracic aortic aneurysm repair/replacement surgeries. Yet little is known about such patients' post-operative outcomes or the role of post-operative corticosteroids. The study was undertaken across three tertiary referral hospitals in Sydney, Australia. Prospectively collected data for all thoracic aortic repair/replacement patients between 2004 and 2018 was accessed from a national surgical registry and analysed. Histopathology records identified cases of inflammatory aortitis which were subclassified as clinically isolated aortitis (CIA), giant cell arteritis (GCA), Takayasu (TAK) or other aortitis. Between-group outcomes were compared utilising logistic and median regression analyses. Between 2004 and 2018, a total of 1119 thoracic aortic surgeries were performed of which 41 (3.7%) were inflammatory aortitis cases (66% CIA, 27% GCA, 5% TAK, 2% other). Eight out of 41 (20%) aortitis patients received post-operative corticosteroids. Compared to non-aortitis patients, the aortitis group was predominantly female (53.7% vs. 28.1%, p < 0.01), was older (mean 70 vs. 62 years, p < 0.01) and had higher prevalence of hypertension (82.9% vs. 67.1%, p = 0.03) and pre-operative immunosuppression (9.8% vs. 1.4%, p < 0.01). There was no difference (p > 0.05) between aortitis and non-aortitis groups for 30-day mortality (7.3% vs 6.5%), significant morbidity (14.6% vs. 22.4%), or infection (9.8% vs. 6.4%). Outcomes were similar for the non-corticosteroid-treated aortitis subgroup. Histologic evidence of inflammatory thoracic aortitis following surgery did not affect post-operative mortality or morbidity. Withholding corticosteroids did not adversely affect patient outcomes. These findings will assist rheumatologists and surgeons in the post-operative management of aortitis.

Atrial fibrillation management during septal myectomy for hypertrophic cardiomyopathy: A systematic review.

INTRODUCTION: Atrial fibrillation is common in patients with hypertrophic cardiomyopathy, and significantly impacts mortality and morbidity. In patients with atrial fibrillation undergoing septal myectomy, concomitant surgery for atrial fibrillation may improve outcomes. METHODS: A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies reporting the outcomes of combined septal myectomy and atrial fibrillation surgery were included. RESULTS: A total of 10 observational studies were identified, including 644 patients. Most patients had paroxysmal atrial fibrillation. The proportion with prior unsuccessful ablation ranged from 0 to 19%, and preoperative left atrial diameter ranged from 44 ± 17 to 52 ± 8 mm. Cox-Maze IV (n = 311) was the most common technique used, followed by pulmonary vein isolation (n = 222) and Cox-Maze III (n = 98). Patients with persistent or longstanding atrial fibrillation more frequently received Cox-Maze III/IV. Ranges of early postoperative outcomes included: mortality 0 to 7%, recurrence of atrial tachyarrhythmias 4.4 to 48%, cerebrovascular events 0 to 1.5%, and pacemaker insertion 3 to 21%. Long-term data was limited. Freedom from atrial tachyarrhythmias at 1 year ranged from 74% to 96%, and at 5 years from 52% to 100%. Preoperative predictors of late atrial tachyarrhythmia recurrence included left atrial diameter >45 mm, persistent or longstanding preoperative atrial fibrillation and longer atrial fibrillation duration. CONCLUSION: In patients with atrial fibrillation undergoing septal myectomy, the addition of ablation surgery adds low overall risk to the procedure, and likely reduces the risk of recurrent atrial fibrillation in the long term. Future randomised studies comparing septal myectomy with or without concomitant AF ablation are needed.

Intracardiac Echocardiography for Point-of-Care Guided Left Ventricular Assist Device Implantation: Surgical Implications for COVID-19.

Data from animal models is now available to initiate assessment of human safety and feasibility of wide-angle three-dimensional intracardiac echocardiography (3D ICE) to guide point-of-care implantation of percutaneous left ventricular assist devices in critical care settings. Assessment of these combined new technologies could be best achieved within a surgical institution with pre-existing expertise in separate utilization of ICE and Impella.

Models of cardiovascular surgery biobanking to facilitate translational research and precision medicine.

Biobanking in health care has evolved over the last few decades from simple biological sample repositories to complex and dynamic units with multi-organizational infrastructure networks and has become an essential tool for modern medical research. Cardiovascular tissue biobanking provides a unique opportunity to utilize cardiac and vascular samples for translational research into heart failure and other related pathologies. Current techniques for diagnosis, classification, and treatment monitoring of cardiac disease relies primarily on interpretation of clinical signs, imaging, and blood biomarkers. Further research at the disease source (i.e. myocardium and blood vessels) has been limited by a relative lack of access to quality human cardiac tissue and the inherent shortcomings of most animal models of heart disease. In this review, we describe a model for cardiovascular tissue biobanking and databasing, and its potential to facilitate basic and translational research. We share techniques to procure endocardial samples from patients with hypertrophic cardiomyopathy, heart failure with reduced ejection fraction, and heart failure with preserved ejection fraction, in addition to aortic disease samples. We discuss some of the issues with respect to data collection, privacy, biobank consent, and the governance of tissue biobanking. The development of tissue biobanks as described here has significant scope to improve and facilitate translational research in multi-omic fields such as genomics, transcriptomics, proteomics, and metabolomics. This research heralds an era of precision medicine, in which patients with cardiovascular pathology can be provided with optimized and personalized medical care for the treatment of their individual phenotype.

PROSE: Prospective Randomized Trial of the On-X Mechanical Prosthesis and the St Jude Medical Mechanical Prosthesis Evaluation : Part 1(Patient Dynamics): Preoperative demographics and preoperative and operative risk factors.

OBJECTIVES: The PROSE trial purpose is to investigate whether the incidence of thromboembolic-related complications is reduced with a current generation mechanical prosthesis (On-X Life Technologies/CryoLife Inc.-On-X) compared with a previous generation mechanical prosthesis (St Jude Medical-SJM). The primary purpose of the initial report is to document the preoperative demographics, and the preoperative and operative risk factors by individual prosthesis and by Western and Developing populations. METHODS: The PROSE study was conducted in 28 worldwide centres and incorporated 855 subjects randomized between 2003 and 2016. The study enrollment was discontinued on August 31, 2016. The preoperative demographics incorporated age, gender, functional class, etiology, prosthetic degeneration, primary rhythm, primary valve lesion, weight, height, BSA and BMI. The preoperative and operative evaluation incorporated 24 risk factors. RESULTS: The total patient population (855) incorporated On-X population (462) and the St Jude Medical population (393). There was no significant difference of any of the preoperative demographics between the On-X and SJM groups. The preoperative and operative risk factors evaluation showed there was no significant difference between the On-X and St Jude Medical populations. The preoperative and operative risk factors by valve position (aortic and mitral) also documented no differentiation. The dominant preoperative demographics of the Western world population were older age, male gender, sinus rhythm, aortic stenosis, congenital aortic lesion, and mitral regurgitation. The dominant demographics of the Developing world population were rheumatic etiology, atrial fibrillation, aortic regurgitation, mixed aortic lesions, mitral stenosis and mixed mitral lesions. The Developing world group had only one significant risk factor, congestive heart failure. The majority of the preoperative and operative risk factors were significant in the Western world population. CONCLUSIONS: The preoperative demographics do not differentiate the prostheses but do differentiate the Western and Developing world populations. The preoperative and operative risk factors do not differentiate the prostheses BUT do differentiate the Western and Developing world populations.

Optimizing the discovery and assessment of therapeutic targets in heart failure with preserved ejection fraction.

There is an urgent need for models that faithfully replicate heart failure with preserved ejection fraction (HFpEF), now recognized as the most common form of heart failure in the world. In vitro approaches have several shortcomings, most notably the immature nature of stem cell-derived human cardiomyocytes [induced pluripotent stem cells (iPSC)] and the relatively short lifespan of primary cardiomyocytes. Three-dimensional 'organoids' incorporating mature iPSCs with other cell types such as endothelial cells and fibroblasts are a significant advance, but lack the complexity of true myocardium. Animal models can replicate many features of human HFpEF, and rodent models are the most common, and recent attempts to incorporate haemodynamic, metabolic, and ageing contributions are encouraging. Differences relating to species, physiology, heart rate, and heart size are major limitations for rodent models. Porcine models mitigate many of these shortcomings and approximate human physiology more closely, but cost and time considerations limit their potential for widespread use. Ex vivo analysis of failing hearts from animal models offer intriguing possibilities regarding cardiac substrate utilisation, but are ultimately subject to the same constrains as the animal models from which the hearts are obtained. Ex vivo approaches using human myocardial biopsies can uncover new insights into pathobiology leveraging myocardial energetics, substrate turnover, molecular changes, and systolic/diastolic function. In collaboration with a skilled cardiothoracic surgeon, left ventricular endomyocardial biopsies can be obtained at the time of valvular surgery in HFpEF patients. Critically, these tissues maintain their disease phenotype, preserving inter-relationship of myocardial cells and extracellular matrix. This review highlights a novel approach, where ultra-thin myocardial tissue slices from human HFpEF hearts can be used to assess changes in myocardial structure and function. We discuss current approaches to modelling HFpEF, describe in detail the novel tissue slice model, expand on exciting opportunities this model provides, and outline ways to improve this model further.

The Impact of COVID-19 on the Provision of Adult Cardiac Surgery at a Dedicated COVID Hospital in Australia.

BACKGROUND: Internationally, the response to the COVID-19 pandemic has resulted in fewer cardiac surgical procedures being performed and an increase in the proportion of non-elective cases. To date there has been no study examining the impact of COVID-19 on the provision of cardiac surgery in Australia. AIM: The aim of this study was to evaluate the impact that the COVID-19 pandemic has had on the provision of cardiac surgery in a single, large major cardiac centre and dedicated COVID-19 hospital. A retrospective cohort study was undertaken utilising prospectively collected data. METHODS: Prospectively collected patient and operative data was examined to assess whether there was a reduction in the number of cases performed and whether there was a difference in patient demographics, surgical procedures or case urgency. Data was examined from the period of COVID-restrictions in 2020 and compared with data from the same time period in 2019. RESULTS: From 3 March 2020 to 30 June 2020, 136 adults underwent cardiac surgery at our institution, representing an overall reduction in operative caseload of 21%. The largest impact was noticed in May and April and coincided with statewide restrictions on elective surgery. Surgical acuity was unchanged with 58% of operations classified as non-elective procedures performed during the index admission. There was a small non-significant increase in the proportion of isolated coronary artery bypass surgery and aortic valve surgeries performed. CONCLUSION: From March to June 2020 our local hospital response to the COVID-19 pandemic resulted in a reduction in cardiac surgery service delivery. No change was seen in the urgency or type of surgeries performed.

Five-Year Survival of Transcatheter Aortic Valve Implantation in High-Risk Patients.

BACKGROUND: Although transcatheter aortic valve implantation (TAVI) has become the standard treatment for severe aortic stenosis in high-risk patients in Australia, there is still limited data on long term survival. METHODS: All patients undergoing TAVI at a single tertiary institution between September 2009 and December 2015 were included. The primary outcome was survival, by linkage of patients with the National Death Index of the Australian Institute of Health and Welfare. Post-procedure data and echocardiographic measurements were retrospectively analysed for all patients. RESULTS: A total of 186 patients were included. It was a high-risk patient population (mean EuroSCORE 31.5±20.5, mean age 83.0±8.2 years). Valve prostheses used were Edwards SAPIEN (ES) (Edwards, Irvine, CA, USA) in 16.1%, Edwards SAPIEN XT (ESXT) in 74.2%, and Medtronic CoreValve (MCV) (Medtronic, Minneapolis, MN, USA) in 9.7%. Median survival time for the entire cohort was 68.2 months (95% Confidence Interval [CI]; Lower Limit [LL] 58.0 months, Upper Limit [UL] not defined). The 2- and 5-year estimates of survival were 85% (LL 80%, UL 90%) and 56% (LL 48%, UL 66%), respectively. There was no statistically significant difference in median survival between the ES and ESXT valves, or implantation approach. Survival was greater in patients with creatinine <200 µmol/L compared to >200 µmol/L (68.8 months [LL 61.4, UL n/a] vs 48.0 months [LL 25.5, UL n/a]). Over the study period, there was a statistically significant trend in increasing mean transvalvular gradient (ES: 1.66 mmHg/yr, p=0.0058; ESXT: 2.50 mmHg/yr, p≤0.001) and maximum velocity (ESXT: 0.16 m/s/yr, p=0.004) and decreasing valve area (ESXT: -0.07 cm2/yr, p<0.001). There was substantial attrition of patient echocardiographic follow-up (number of echocardiograms followed up at 5 years=6, number at risk=41). CONCLUSIONS: This study has demonstrated acceptable survival in a high-risk cohort of patients undergoing TAVI, with comparable results to larger international experiences. There was a trend for worsening haemodynamics that needs to be monitored. Future studies need to examine patient quality of life and the performance of newer generation prostheses.

Contemporary outcomes of continuous-flow biventricular assist devices.

BACKGROUND: Significant right ventricular failure (RVF) complicating left ventricular assist device (LVAD) placement has been reported at 10-30%. Although primarily indicated for left ventricular failure, ventricular assist devices (VADs) have become utilized in a biventricular setup to combat right ventricular failure (RVF) following LVAD implantation. With the advent of continuous-flow LVADs (CF-LVADs) superseding their pulsatile predecessors, the shift towards CF-biventricular assist devices (CF-BiVADs) come with the prospect of improved outcomes over previous pulsatile BiVADs. We aim to review the literature and determine the outcomes of CF-BiVAD recipients. METHODS: A systematic review was performed to determine the outcomes of CF-BiVADs. Pre-operative demographics and device configuration data was collected. Primary outcomes evaluated were short-term survival, long-term survival, duration of support, and survival to transplant. Secondary outcomes evaluated included intensive care unit (ICU) and hospital length of stay (ICU-LOS and HLOS, respectively), pump thrombosis, pump exchange. Median and interquartile range was reported where appropriate. A major limitation was the likely overlap of cohorts across publications, which may have contributed to some selection bias. RESULTS: Of 1,282 screened, 12 publications were evaluated. Sample size ranged from 4 to 93 CF-BiVAD recipients, and follow-up ranged from 6 to 24 months. Mean age ranged from 34 to 52 years old. Forty-five percent of CF-BiVADs had right atrial (RA-) inflow cannulation, with the remaining being right ventricular (RV). Thirty-day survival was a median of 90% (IQR 82-97.8%) and 12-month survival was a median of 58.5% (IQR 47.5-62%). Where reported, rate of pump thrombosis (predominantly the right VAD) was a median of 31% (IQR 14-36%), although pump exchange was only 9% (IQR 1.5-12.5%). CONCLUSIONS: RVF post-LVAD implantation is a high morbidity and mortality complication. There is no on-label continuous-flow RVAD currently available. Thus, the modifications of LVADs for right ventricular support to combat pump thrombosis has resulted in various techniques. BiVAD recipients are predominantly transplant candidates, and complications of pump thrombosis and driveline infection whilst on wait-list are of great consequence. This study demonstrates the need for an on-label CF-BiVAD.