Right-Sided Infective Endocarditis: The Importance of Vegetation Size.

BACKGROUND: Right-sided infective endocarditis (IE) carries favourable prognosis compared to left-sided IE. However, the prognostic significance of vegetation size in right-sided IE is less well defined. This study reports the clinical, microbiological, and echocardiographic findings associated with right-sided IE and examines the predictors of adverse outcomes. METHODS: Consecutive adults admitted with isolated right-sided IE at an Australian tertiary referral centre between June 1999 and May 2017 were retrospectively reviewed. Patients were stratified according to intravenous drug user (IVDU) status. Culprit organisms, sepsis severity, treatment regimens, inpatient complications, and vegetation size were recorded. Hospital survivors were followed mean 6.9±4.8 years for late mortality and IE recurrence. RESULTS: Of 318 consecutive cases of IE, 60 (19%) were isolated right-sided IE and included in this study. Forty-three (43) (72%) patients were current IVDUs, who were younger and more likely to have hepatitis. The majority (90%) of patients were medically managed with multi-agent antimicrobial regimens (median three agents) for a total duration of median 91 days. In-hospital mortality was 3% (2/60). Septic emboli were found in 82% (49/60) of patients, were significantly more common among IVDUs but were not related to vegetation size. Survival after hospital discharge was 100% at 1 year, 96% at 3 years, and 89% at 5 years. Vegetation size >2 cm, chronic kidney disease, and Pitt bacteraemia score were independent predictors of all-cause late mortality. Freedom from IE recurrence was 93% at 1 year, 87% at 3 years, and 84% at 5 years. Vegetation >2.5 cm, prisoner status, and multivalvular IE involvement conferred higher risks of recurrence. CONCLUSIONS: Patients with right-sided IE and small vegetations do well with medical management and this should continue to be the preferred strategy. However, those with large vegetations have poorer late outcomes and may require more aggressive treatment and closer follow-up.

Cardiovascular disease and COVID-19: Australian and New Zealand consensus statement.

INTRODUCTION: The coronavirus 2019 disease (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Pre-existing cardiovascular disease (CVD) increases the morbidity and mortality of COVID-19, and COVID-19 itself causes serious cardiac sequelae. Strategies to minimise the risk of viral transmission to health care workers and uninfected cardiac patients while prioritising high quality cardiac care are urgently needed. We conducted a rapid literature appraisal and review of key documents identified by the Cardiac Society of Australia and New Zealand Board and Council members, the Australian and New Zealand Society of Cardiac and Thoracic Surgeons, and key cardiology, surgical and public health opinion leaders. MAIN RECOMMENDATIONS: Common acute cardiac manifestations of COVID-19 include left ventricular dysfunction, heart failure, arrhythmias and acute coronary syndromes. The presence of underlying CVD confers a five- to tenfold higher case fatality rate with COVID-19 disease. Special precautions are needed to avoid viral transmission to this population at risk. Adaptive health care delivery models and resource allocation are required throughout the health care system to address this need. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: Cardiovascular health services and cardiovascular health care providers need to recognise the increased risk of COVID-19 among CVD patients, upskill in the management of COVID-19 cardiac manifestations, and reorganise and innovate in service delivery models to meet demands. This consensus statement, endorsed by the Cardiac Society of Australia and New Zealand, the Australian and New Zealand Society of Cardiac and Thoracic Surgeons, the National Heart Foundation of Australia and the High Blood Pressure Research Council of Australia summarises important issues and proposes practical approaches to cardiovascular health care delivery to patients with and without SARS-CoV-2 infection.

Effects of Preoperative Angiotensin-Converting Enzyme Inhibitor Therapy on Postoperative Renal Function in Cardiac Surgery.

A Best Evidence Topic in cardiac surgery was written according to a structured protocol. The question addressed was-"In patients who undergo cardiac surgery, is preoperative angiotensin-converting enzyme inhibitor therapy associated with postoperative renal dysfunction?" Altogether, 339 papers were found using the reported search. Ten (10) were chosen which best answered the clinical question. The papers were evaluated for bias and heterogeneity using validated tools and the collected results analysed qualitatively. Evidence in the current literature is inconclusive that preoperative administration of angiotensin-converting enzyme inhibitor therapy affects postoperative renal dysfunction in patients undergoing cardiac surgery.

Vein Graft Patency Rates With Aspirin Plus Clopidogrel Following Coronary Artery Bypass Grafting.

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was, "In patients who have undergone Coronary Artery Bypass Grafting, does aspirin plus clopidogrel postoperatively improve vein graft patency when compared to aspirin alone?" Altogether, 165 papers were found using the reported search, of which five represented the best evidence to answer the clinical question. Overall analysis of these papers demonstrated similar rates of vein graft patency between the two groups. There was no difference between the groups with regard to mortality, adverse bleeding-related outcomes, or composite vascular events.

Early transthoracic echocardiography has useful prognostic value in left-sided native valve endocarditis despite limited diagnostic performance.

To investigate the prognostic implications of findings on early transthoracic echocardiography (TTE) in patients with definite left-sided native valve infective endocarditis (LNVIE). We reviewed a 10-year retrospective cohort of consecutive patients with definite LNVIE treated at a tertiary cardiothoracic centre. TTE studies performed within the first seven days of the index blood culture (for culture-positive cases) or hospital admission (for culture-negative cases) were reviewed for the presence of valvular vegetations, perivalvular abscesses, aortic or mitral regurgitation of moderate or greater severity or a bicuspid aortic valve. Six-week outcomes included all-cause mortality, cardiac surgery for endocarditis or new embolic cerebral infarction. Early TTE was performed in 118 of 151 episodes of definite LNVIE at a median of two days after the index blood culture or hospital admission. Findings on these studies included valvular vegetations or abscesses in 74 patients, moderate or severe aortic or mitral regurgitation in 67 patients and a bicuspid aortic valve in 19 patients. The presence of any of these findings conferred a relative risk of any adverse six-week outcome of 4.80 (95% confidence interval 1.6-17, p = 0.001). The presence of a bicuspid aortic valve appeared particularly predictive of the need for cardiac surgery, including for clinically occult paravalvular abscesses. Early TTE can be used to stratify patients with LNVIE by the risk of major endocarditis-related adverse outcomes occurring within the first six weeks of treatment.

Management of atrial fibrillation after cardiac surgery.

A best evidence topic in cardiac surgery was written according to a structured protocol addressing the question 'for post-cardiac surgery atrial fibrillation (AF), do clinical outcomes differ between rate or rhythm control strategies?' Altogether, 2174 papers were found using the reported searches, of which 5 represented the best evidence to answer the clinical question. Hospital length of stay ranged from 5.0 to 13.2 days for rate control and 5.2 to 10.3 days for rhythm control. Freedom from AF at follow up was achieved in 84.2-91 and 84.2-96% in rate and rhythm control groups respectively. Minimal serious adverse events were noted in all studies analysed and there was no difference between rate and rhythm control groups. We conclude that in the management of post-cardiac surgery, AF, rate control and rhythm control are equivalent in terms of hospital length of stay, freedom from arrhythmia at follow up and complication rates.

Contemporary review of severe aortic stenosis.

Severe aortic stenosis (AS) is the most common form of valvular heart disease in the developed world, with a rising prevalence due to an ageing Australian population. Transcatheter aortic valve implantation (TAVI) offers a less invasive option for the treatment of severe AS, with evidence supporting TAVI compared with medical therapy in inoperable patients and superior with surgical aortic valve replacement (SAVR) in high-risk patients. Equal outcomes have been observed in all-comer intermediate-risk populations. The Heart Team utilises a shared decision-making approach between physicians and surgeons in risk-stratifying patients and reduces the intrinsic bias that may occur if decisions are made in isolation. Geriatric assessment is useful for identifying preoperative frailty, a major risk factor for death post-aortic valve intervention. In severe AS, a decision can be made collaboratively to pursue TAVI, SAVR, a Ross Procedure or conservative management. The learning curve associated with TAVI has improved markedly, with overall complication rates decreasing around the world. Contemporary changes in practice, such as conscious sedation without general anaesthesia, expedited recovery and early discharge, will likely improve cost-effectiveness. In 2018, TAVI is a well-established procedure in Australia that has revolutionised the management of severe AS. In the future, with an expanding elderly population, the number of patients to benefit from transcatheter therapies for severe AS is hypothesised to increase 4-10-fold. Heart Team assessment is crucial in patients with severe AS to direct appropriate management.

Left Atrial Appendage Exclusion Using the AtriClip Device: A Case Series.

BACKGROUND: Atrial fibrillation (AF) affects 1.5-2% of the population and is associated with a five-fold increased lifetime risk of stroke [1]. The left atrial appendage (LAA) is the source of embolic strokes in up to 90% of patients with non-valvular AF with clots in the left atrium [2]. METHODS: We reviewed the clinical notes and echocardiographic findings of 20 patients who underwent open cardiac surgery in which concurrent AtriClip (Atricure Inc, Westchester, OH, USA) device insertion was attempted at our institution from July 2013 to February 2015. This was to examine the safety and efficacy of LAA exclusion with clip devices during open cardiac surgery. Indications for LAA exclusion included a history or suspicion of atrial arrhythmia, left ventricular dilatation, or a history of transient ischaemic attacks. RESULTS: All 20 of the 20 participants had successful placement of the clip device (100% success rate). There were no adverse events related to the device and no perioperative mortality. There were three late deaths due to chronic obstructive pulmonary disease (COPD), leukaemia, and refractory congestive cardiac failure. No late device related complications were found on follow-up imaging in the remaining patients. CONCLUSIONS: The results of our study demonstrate the LAA exclusion during open cardiac surgery with the AtriClip device is safe, has a 100% success rate, and appears to be stable over time.

Levosimendan Following Cardiac Surgery.

A best evidence topic was written to address if perioperative levosimendan improves mortality following cardiac surgery. Fourteen papers represented the best available evidence. An older meta-analysis summarising 11 of these trials concluded that there were fewer deaths in the levosimendan group compared to the control group (OR 0.41, p <0.001) however, this was driven by the results of three included trials by the same author. Three larger and more recent randomised controlled trials failed to demonstrate significant differences in mortality. We conclude that levosimendan lacks robust evidence to substantiate claims of mortality benefit in cardiac surgery patients and should not be used routinely in such patients.

Platelet transfusion is not associated with increased mortality or morbidity in patients undergoing cardiac surgery.

BACKGROUND: Transfusion of platelets is common in cardiac surgery, and while there are guidelines for their use, there are concerns about potential risks. We aimed to assess the impact of platelet transfusion on mortality, thrombosis, and infection in this patient group. STUDY DESIGN AND METHODS: A retrospective cohort study of all patients at St Vincent's Hospital Melbourne who underwent a first cardiac surgery procedure from June 2001 to June 2014 was conducted. A propensity-weighted analysis was performed to examine the association between intraoperative platelet transfusion and outcomes. RESULTS: A total of 5233 patients met inclusion criteria, and 531 (10.15%) received intraoperative platelet transfusion (median two platelet doses, interquartile range, 1-17). Patients receiving platelets were older, had higher body mass index, lower rates of diabetes and dyslipidemia, higher rates of infective endocarditis, recent myocardial infarction and unstable angina, and exposure to aspirin or clopidogrel. On univariable analysis, platelet transfusion was associated with increased 30-day mortality (2.4% vs. 10.55%, p < 0.001), return to theatre for bleeding (3.23% vs. 13.37%, p < 0.001), and rates of any infection (9.26% vs. 19.17%, p < 0.001). After adjusting for confounders, platelet transfusion was not associated with increased risk of 30-day mortality or infective complications. Platelet transfusion was associated with higher rates of return to theatre (relative risk [RR], 2.46; confidence interval [CI], 1.42, 4.04; p = 0.001) and decreased risk of thromboembolic events (RR, 0.28; CI, 0.15, 0.51; p < 0.001). CONCLUSION: Platelet transfusion was not associated with increased mortality or infective complications following first cardiac surgery. Further prospective studies are required to identify patients most likely to benefit from platelet transfusion.

Thirty-day outcomes in Indigenous Australians following coronary artery bypass grafting.

BACKGROUND: Indigenous Australians have higher rates of cardiovascular disease and comorbidities compared to their non-indigenous counterparts. AIMS: We sought to evaluate whether indigenous status per se portends a worse prognosis following isolated coronary artery bypass grafting (CABG). METHODS: The outcomes of 778 Indigenous Australians (55 ± 10 years; 32% female) enrolled in the Australian and New Zealand Society of Cardiac and Thoracic Surgeons registry were compared to 36 124 non-Indigenous Australians (66 ± 10 years; 21% female) following isolated CABG. In a secondary analysis, patients were propensity-matched by age, sex, renal function, diabetes and ejection fraction (778 individuals in each group). RESULTS: Indigenous Australians were younger and more likely to be female and current smokers and to have diabetes, hypertension, renal impairment, heart failure and previous CABG (all P < 0.04). Indigenous patients had fewer bypasses with arterial conduits (including less internal mammary artery use) and a higher number of distal vein anastomoses (P < 0.001). Postoperative bleeding rates were higher in indigenous patients (P = 0.001). However, in-hospital and 30-day all-cause mortality and rates of 30-day readmission were similar between both groups, although cardiac mortality was higher in the indigenous cohort (1.5% vs 0.8%, P = 0.02). With propensity-matching, rates of postoperative complications were similar among the two groups, with the exception of bleeding, which remained higher in Indigenous Australians (P = 0.03). CONCLUSIONS: Despite procedural differences and higher rates of baseline comorbidities, Indigenous Australians do not have worse short-term outcomes following isolated CABG. Given the higher rates of baseline comorbidities and lower rates of arterial conduit use, it will be essential to determine long-term outcomes.

Rapid-Deployment Versus Conventional Bio-Prosthetic Aortic Valve Replacement.

BACKGROUND: The use of rapid-deployment aortic valve replacement (RD-AVR) has burgeoned in recent years. There are few studies comparing RD-AVR to conventional aortic valve replacement (cAVR) and no studies where both were inserted via full sternotomy. As such, we reviewed our experience and compared the two approaches. METHODS: From 2008 to 2015, 597 patients underwent isolated aortic valve replacement ± coronary artery bypass grafting (CABG) at a single centre. During this period, 41 (7%) patients received RD-AVR and 556 (93%) received cAVR. Of those receiving RD-AVR, surgical access was via full median sternotomy in 40 (98%). Propensity score matching yielded 41 matched pairs. Perioperative outcomes were compared. RESULTS: After propensity score matching, the RD-AVR group had shorter aortic cross clamp (X-clamp) (RD-AVR: 71±33min vs. cAVR: 106±42min, p<0.01) and cardiopulmonary bypass (CPB) times (95±42min vs. 134±47min, p<0.01). There was no difference in 30-day mortality (RD-AVR: 2% vs. cAVR: 2%, p>0.99). RD-AVR patients required shorter mean ventilation (17±25 vs. 63±131hrs, p<0.01) and intensive care unit (ICU) stay (51±45 vs. 108±157hrs, p=0.03) times. RD-AVR also had reduced rates of new postoperative atrial arrhythmias (8% vs. 20%, p=0.02). Total length of postoperative hospital stay was similar. Haemodynamic performance for the RD-AVR was within acceptable limits. CONCLUSIONS: The use of RD-AVR results in shorter X-clamp and CPB times and is associated with reductions in perioperative morbidity. RD-AVR is becoming a valuable component of the surgeon's armamentarium in selected patients. Long-term follow-up will reveal the full potential of these devices.

Cardiac Repair With a Novel Population of Mesenchymal Stem Cells Resident in the Human Heart.

Cardiac resident stem cells (CRSCs) hold much promise to treat heart disease but this remains a controversial field. Here, we describe a novel population of CRSCs, which are positive for W8B2 antigen and were obtained from adult human atrial appendages. W8B2(+) CRSCs exhibit a spindle-shaped morphology, are clonogenic and capable of self-renewal. W8B2(+) CRSCs show high expression of mesenchymal but not hematopoietic nor endothelial markers. W8B2(+) CRSCs expressed GATA4, HAND2, and TBX5, but not C-KIT, SCA-1, NKX2.5, PDGFRα, ISL1, or WT1. W8B2(+) CRSCs can differentiate into cardiovascular lineages and secrete a range of cytokines implicated in angiogenesis, chemotaxis, inflammation, extracellular matrix remodeling, cell growth, and survival. In vitro, conditioned medium collected from W8B2(+) CRSCs displayed prosurvival, proangiogenic, and promigratory effects on endothelial cells, superior to that of other adult stem cells tested, and additionally promoted survival and proliferation of neonatal rat cardiomyocytes. Intramyocardial transplantation of human W8B2(+) CRSCs into immunocompromised rats 1 week after myocardial infarction markedly improved cardiac function (∼40% improvement in ejection fraction) and reduced fibrotic scar tissue 4 weeks after infarction. Hearts treated with W8B2(+) CRSCs showed less adverse remodeling of the left ventricle, a greater number of proliferating cardiomyocytes (Ki67(+) cTnT(+) cells) in the remote region, higher myocardial vascular density, and greater infiltration of CD163(+) cells (a marker for M2 macrophages) into the border zone and scar regions. In summary, W8B2(+) CRSCs are distinct from currently known CRSCs found in human hearts, and as such may be an ideal cell source to repair myocardial damage after infarction.

An Australian longitudinal pilot study examining health determinants of cardiac outcomes 12 months post percutaneous coronary intervention.

BACKGROUND: Percutaneous coronary intervention (PCI) is a very common revascularisation procedure for coronary artery disease (CAD). The purpose of this study was to evaluate cardiac outcomes, health related quality of life (HRQoL), resilience and adherence behaviours in patients who have undergone a PCI at two time points (6 and 12 months) following their procedure. METHODS: A longitudinal pilot study was conducted to observe the cardiac outcomes across a cohort of patients who had undergone a percutaneous coronary intervention (PCI). Participants who had undergone PCI 6 months prior were invited. Those participants who met the inclusion criteria and provided consent then completed a telephone survey (time point 1). These participants were then contacted 6 months later (i.e. 12 months post-intervention, time point 2) and the measures were repeated. RESULTS: All patients (n = 51) were recorded as being alive at time point 1. The multiple model indicated that controlling for other factors, gender was significantly associated with a linear combination of outcome measures (p = 0.004). The effect was moderate in magnitude (partial-η(2) = 0.303), where males performed significantly better than females 6 months after the PCI procedure physically and with mood. Follow-up univariate ANOVAs indicated that gender differences were grounded in the scale measuring depression (PHQ9) (p = 0.005) and the physical component score of the short form measuring HRQoL (SF12-PCS) (p = 0.003). Thirteen patients were lost to follow-up between time points 1 and 2. One patient was confirmed to have passed away. The pattern of correlations between outcome measures at time point 2 revealed statistically significant negative correlation between the PHQ instrument and the resilience scale (CD-RISC) (r = -0.611; p < 0.001); and the physical component score of the SF-12 instrument (r = -0.437; p = 0.054). CONCLUSIONS: Men were performing better than women in the 6 months post-PCI, particularly in the areas of mood (depression) and physical health. This pilot results indicate gender-sensitive practices are recommended particularly up to 6 months post-PCI. Any gender differences observed at 6 month appear to disappear at 12 months post-PCI. Further research into the management of mood particularly for women post-PCI is warranted. A more detailed inquiry related to access/attendance to secondary prevention is also warranted.

The Benefits and Pitfalls of the Use of Risk Stratification Tools in Cardiac Surgery.

Risk assessment tools are increasingly used in surgery. In cardiac surgery, risk models are used for patient counselling, surgical decision-making, performance benchmarking, clinical research, evaluation of new therapies and quality assurance, among others. However, they have numerous disadvantages which need to be considered. This article evaluates the utility of risk assessment tools in cardiac surgery including a discussion of their advantages and disadvantages.

Application of Clinical Databases to Contemporary Cardiac Surgery Practice: Where are We now?

Cardiac surgery has embraced and encouraged the use of large, multi-institutional datasets in clinical practice. From a research perspective, database studies have facilitated an increased understanding of cardiac surgery. Among other uses, they have allowed an investigation of disease incidence and mortality, high risk groups, disparities in health care delivery and the impact of new devices and techniques. Databases are also important tools for clinical governance and quality improvement. Despite their obvious utility, clinical databases have limitations; they are subject to treatment bias, contain missing data and cannot establish causality. Moreover, the ongoing maintenance of the database requires significant human and financial resources. In the future, inclusion of more detailed follow-up data and integration with other datasets will improve the utility of clinical databases.

Transcatheter versus Surgical Aortic Valve Replacement in High-risk Patients: A propensity-score matched analysis.

BACKGROUND: There is limited data from Australia and New Zealand comparing transcatheter aortic valve implantation (TAVI) with conventional surgical aortic valve replacement (sAVR). METHODS: Between 2009 and 2015, 64 patients underwent TAVI and 669 underwent sAVR at a single centre. Patients' peri-operative details were analysed and compared between groups. Propensity-score matching was performed for risk adjustment. RESULTS: Patients receiving TAVI were older (mean age in years TAVI: 83.9±4.6 vs. sAVR: 71±9.9, P<0.001), and were more likely to be female (TAVI: 67%, 43/64, vs. sAVR: 32%, 217/669, P <0.001). Unadjusted 30-day mortality was comparable between groups (2/64, 3% vs. 22/669, 3%, P >0.99). The matched analysis revealed comparable 30-day mortality (TAVI: 2/44, 5% vs. sAVR: 2/44, 5%, P > 0.99). New atrial arrhythmia occurred more frequently within the sAVR cohort (TAVI: 1/44, 2% vs. sAVR 18/44, 41%, P <0.001). Complete heart block requiring permanent pacemaker was more frequent amongst the TAVI cohort (TAVI: 10/44, 23% vs. sAVR 2/44, 5%, P=0.039). At two years, survival was comparable between groups (TAVI: 74±1.7 vs. sAVR: 80±0.1%, P=0.65). CONCLUSION: This single centre experience suggests that TAVI is a valuable treatment option for high-risk surgical patients with comparable survival.

Impact of smoking status on outcomes after concomitant aortic valve replacement and coronary artery bypass graft surgery.

BACKGROUND: There is a paucity of data on the impact of smoking status on outcomes after concomitant aortic valve replacement and coronary artery bypass graft (AVR-CABG) surgery. METHODS: Data obtained prospectively between June 2001 and December 2009 by the Australian and New Zealand Society of Cardiac and Thoracic Surgeons National Cardiac Surgery Database Program were retrospectively analyzed. Demographic and operative data were compared between patients who were nonsmokers, previous smokers, and current smokers using chi-square test and t-test. The independent impact of smoking status on 14 short-term complications and long-term mortality was determined using binary logistic and Cox regression, respectively. RESULTS: Concomitant AVR-CABG surgery was performed in 2,563 patients; smoking status was recorded in 2,558 (99.8%) patients. Of these, 1,052 (41.1%) patients had no previous smoking history, 1,345 (52.6%) patients were previous smokers, and 161 (6.3%) patients were current smokers. The 30-day mortality rate was 3.5% in nonsmokers, 4.1% in previous smokers, and 3.1% in current smokers (p = nonsignificant). The incidence of perioperative complications was similar in the three groups. The mean follow-up period for this study was 36 months (range, 0-105 months). After adjusting for differences in patient variables, the incidence of late mortality was higher in previous smokers (hazard ratio [HR], 1.44; 95% confidence interval [CI], 1.14-1.81; p = 0.002) compared with nonsmokers. A trend toward increased late mortality in current smokers was noted (HR, 1.34; 95% CI, 0.86-2.08; p = 0.201). CONCLUSION: Smoking is not associated with adverse outcomes after concomitant AVR-CABG surgery. Smoking status should not, therefore, preclude these patients from undergoing this procedure. Given the adverse effect of smoking on overall cardiovascular morbidity and mortality and late postoperative mortality, patients should be encouraged to quit smoking.