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Background: Rheumatic heart disease (RHD) remains an important cause of morbidity and mortality in New Zealand. Factors associated with the choice of surgical treatment for advanced RHD in young adults are poorly understood. We sought to review our local experience with the surgical management of young adults with rheumatic mitral valvular disease. Methods: From 2003 to 2016, all patients aged 15–24 years undergoing mitral valve surgery for rheumatic disease at Auckland City Hospital, New Zealand were retrospectively reviewed. Results: During the 13‐year study period, 73 young adults underwent mitral surgery; 85% were Maori or Pacific Islanders. Mitral repair was performed in 32 patients and replacement in 41 patients. Isolated mitral valve surgery was performed in 36%, double valve procedures in 47%, and triple valve procedures in 17% of patients. The 30‐day mortality rate and stroke rate were 1.4% and 2.7% respectively. The medium‐term mortality rate was 11.9% across a mean follow‐up of 6 years (6.9% in the repair group, 15.8% in the replacement group, p = 0.25). There were increased bleeding complications (p = 0.04) in patients with mechanical mitral valve replacement. For patients on warfarin, across medium‐term follow‐up, the INR was in the therapeutic range only 23% of the time. Conclusion: Most young adults in New Zealand with severe RHD requiring surgery are of indigenous Maori or Pacific Island ethnicity. There is a trend towards improved survival with mitral repair. There is a significant tendency towards increased bleeding complications in patients on warfarin for mechanical mitral replacement. Warfarin compliance is poor. [ABSTRACT FROM AUTHOR]

Introduction: Isolated tricuspid valve surgery is an uncommon operation. Historical reports, including a previous review from our unit, demonstrated high morbidity and mortality associated with this operation. Many of these patients had severely impaired right ventricular function at the time of the surgery. Since our previous review, we have actively encouraged our local cardiologists to refer patients with severe isolated tricuspid disease for surgery before right ventricular remodelling occurs. This present study was performed to assess our current results.Material and Methods: A prospectively-maintained hospital database was used to identify all adult non-congenital patients receiving standalone tricuspid valve repair or replacement at New Zealand's largest cardiothoracic surgical unit from July 2011 to July 2019. Additional demographic and clinical data were collected by review of patient electronic records.Results: During the 8-year study period, a total of 50 patients underwent isolated tricuspid valve surgery. Most patients were operated on for functional (40%) or rheumatic (30%) tricuspid disease. The majority of patients underwent surgery when the right ventricular function preoperatively was normal (30%) or mildly/moderately impaired (60%). Over half the patient sample (56%) underwent valve replacement. The 30-day mortality rate and stroke rate were 6% and 2% respectively. The medium-term survival was 80% at 4 years mean follow-up.Conclusion: Isolated tricuspid surgery is no longer a high mortality operation when it is performed on patients who have preserved right ventricular function. [ABSTRACT FROM AUTHOR]

Background: The updated Australian System for Cardiac Operative Risk Evaluation (AusSCORE II) and the Society of Thoracic Surgeons (STS) Score are well-established tools in cardiac surgery for estimating operative mortality risk. No validation analysis of both risk models has been undertaken for a contemporary New Zealand population undergoing isolated coronary bypass surgery. We therefore aimed to assess the efficacy of these models in predicting mortality for New Zealand patients receiving isolated coronary artery bypass grafting (CABG).Material and Methods: A prospective database was maintained of patients undergoing isolated CABG at a major tertiary referral centre in New Zealand between September 2014 and September 2017. This database collected the patients' demographic, clinical, biochemical, operative and mortality data. The primary outcome measure was the correlation between the predicted AusSCORE II and STS Score mortality risks and the observed 30-day mortality events for all patients in the database using discrimination and calibration statistics. Discrimination and calibration were assessed using receiver operating characteristic (ROC) curves and the Hosmer-Lemeshow test respectively.Results: A total of 933 patients underwent isolated CABG during the 3-year study period. There were seven deaths in the study cohort occurring within 30 days of surgery. Discrimination analysis demonstrated the area under the ROC curve (AUC) of the AusSCORE II and STS Score as 88.2% (95% CI: 85.9-90.2, p<0.0001) and 92.1% (95% CI: 90.2-93.7, p<0.0001) respectively. Calibration analysis revealed Hosmer-Lemeshow test p-values for the AusSCORE II and STS Score as 0.696 and 0.294 respectively.Discussion: ROC curve analysis produced very high and statistically significant AUC values for the AusSCORE II and STS Score. Hosmer-Lemeshow test analysis revealed that both risk scoring tools are well calibrated for our study cohort. Therefore, the AusSCORE II and STS Score are both strongly predictive of 30-day mortality for isolated coronary artery bypass grafting surgery in our New Zealand patient population. Both risk models have performed with excellent discrimination and calibration. There is, however, a need to consider the performance of these risk stratification models in other cardiac surgical procedures outside isolated coronary bypass surgery where appropriate. [ABSTRACT FROM AUTHOR]

Hyponatremia is a common electrolyte disorder. This can be associated with nausea, disorientation and in more serious cases a decreased level of consciousness or neurological deficits. These symptoms may lead to increases in the cost of hospital care and significant morbidity. The purpose of this retrospective, observational cohort study is to investigate the impact of hyponatremia on patient and systems specific outcome measures in those undergoing elective, unilateral total knee arthroplasty (TKA) at two hospitals in Auckland, New Zealand over a twelve-month period. Patients were stratified into two groups based on the presence or absence of post-operative hyponatremia (defined as a blood sodium of <135 mmol/L with a concurrent decrease of ≥5 mmol/L between the pre- and post-operative recordings). Outcomes collected included Quality of Recovery – 15 (QOR) scores, time to assisted mobilisation, discharge ICD-10 complication codes and hospital length of stay. During the study period 236 patients underwent surgery. Eighty-six (36.4%) patients met criteria for post-operative hyponatremia. This finding was associated with prolongation of the hospital length of stay (4.17 (3.26–5.18) versus 4.28 (3.31–5.45) days, p = 0.031) and a reduction in the QOR score on the second post-operative day (113.0 (99.5–126.5) versus 105.0 (94.0–118.0), p = 0.039). There was no difference in the time to assisted mobilisation. Hyponatremia is a common finding following TKA. This abnormality is associated with small changes in patient specific outcome measures. These implications of these findings may become more significant in settings where same day or rapid discharge from hospital is targeted. [ABSTRACT FROM AUTHOR]

Background: The updated European System for Cardiac Operative Risk Evaluation (EuroSCORE II) is a well-established cardiac surgery risk scoring tool for estimating operative mortality. This risk stratification system was derived from a predominantly European patient cohort. No validation analysis of this risk model has been undertaken for the New Zealand population across all major cardiac surgery procedures. We aim to assess the efficacy (discrimination and calibration) of the EuroSCORE II for predicting mortality in cardiac surgical patients at a large New Zealand tertiary centre.Methods: Data was prospectively collected on patients undergoing cardiac surgery from September 2014 to September 2017 at Waikato Hospital, New Zealand. Patient demographic information, preoperative clinical risk factors and outcome data were entered into a national database. Included patients received either isolated coronary artery bypass grafting (CABG), isolated valve surgery, isolated thoracic aortic surgery, or a combination of these procedures. The primary outcome was the discrimination and calibration of predicted EuroSCORE II risk scores compared with observed 30-day mortality events.Results: 1,666 cardiac surgery patients were included during the study period, with an average EuroSCORE II of 2.97% (95% confidence interval (CI): 2.76-3.18). Nine hundred thirty-three (933) patients underwent isolated CABG, 384 underwent isolated valve surgery, 48 received isolated thoracic aortic surgery and 301 received combination procedures. Thirty-day (30-day) mortality events in each of these groups was 7, 4, 2 and 13 deaths respectively. There were 26 deaths across the total cohort at 30-days (observed mortality rate 1.56%). Discrimination analysis using receiver operating characteristic curves demonstrated the area under the curve (AUC) of the EuroSCORE II in each of these groups as 93.4% (95% CI: 91.6-94.9, p<0.0001), 66.3% (95% CI: 61.3-71.0, p=0.37), 37.0% (95% CI: 15.7-58.2, p=0.23) and 74.8% (95% CI: 69.5-79.6, p<0.0001) respectively. The total cohort AUC was 83.1% (95% CI: 81.2-84.9, p<0.0001). Calibration analysis using Hosmer-Lemeshow tests for the subgroups revealed p-values of 0.848, 0.114, 0.638 and 0.2 respectively. The total cohort Hosmer-Lemeshow p-value was 0.317.Conclusions: EuroSCORE II showed a strong discriminative ability for isolated CABG 30-day mortality in a New Zealand patient cohort. However, the scoring system discriminated poorly across valvular, thoracic aortic or complex combination cardiac surgical procedures. Good calibration of the EuroSCORE II was achieved across both the total cohort and subgroups. It is important to consider the performance of other cardiac surgery risk stratification models for the New Zealand population. [ABSTRACT FROM AUTHOR]

Aim: Child restraint practices among New Zealand children have fallen short of best practice recommendations. In 2013, New Zealand child restraint legislation was amended. The aim of the present study was to determine the child restraint practices of a cohort of children admitted to hospital and how practices have changed since the amendment in child restraint legislation., Methods: We conducted interviews with the parents of 300 paediatric inpatients aged 0-13 years. Data were recorded on their child's usual child restraint use, the restraint used during their trip to hospital, and parental knowledge of child restraint law and best practice recommendations. We compared their responses with those of our survey published in 2013, which was performed before the amendment in child restraint legislation., Results: The median age of the 300 children was three years: 181 (60%) were aged 0-4 years, 65 (22%) 5-9 years and 54 (18%) 10-13 years. One hundred and thirty-six (45%) were girls. Of children <5 years of age, 97% always used a child restraint. Of children 5-9 years of age, 60% always used a child restraint, 12% sometimes and 28% never. A significantly greater proportion of 5-9 year-old children used a child restraint at least some of the time in the present study compared to the 2013 study (47/65 versus 27/53, OR 2.49 [95%CI 1.09-5.81]). Child restraint use declined in children <6 years of age. On their journey to hospital, five children used no restraint, four of whom were held in the arms of a caregiver. Parental knowledge of child restraint recommendations correlated inversely with their compliance with the recommendations (OR 0.33 [95%CI 0.11-0.91])., Conclusions: Consideration should be given to extending child restraint legislation to children older than seven years of age. Further studies could explore the barriers parents face to the use of child restraints and the potential effect of extending child restraint laws to older children., Competing Interests: Nil.