Long-term survival after aortic valve replacement with the Mitroflow bioprosthesis : a comparative study

Background Recent case reports of early structural degeneration of the Mitroflow valve have cast doubts on the suitability of this bioprosthesis, particularly in the smaller sizes, and in younger patients. We studied long-term patient survival, in a comparative study, as a marker of success after aortic valve replacement. Methods Long-term survival in 142 consecutive patients implanted with the Mitroflow valve was compared, using the Kaplan-Meier method, with a control group of 149 patients receiving different bioprostheses. Ninety two percent of patients were over 70 years and the Mitroflow was used preferentially in smaller sizes. Results Long-term survival in patients who received a Mitroflow valve was equivalent to controls. Four documented cases of premature structural valve degeneration (3 Mitroflow, 1 Perimount) required a second intervention. Conclusions The Mitroflow compared favorably with other valves in our practice. Although a few patients required further treatment this had no significant adverse impact on overall survival.peer-reviewe

The impact of dog therapy on nursing students’ heart rates and ability to pay attention in class

In this study we explored if the presence of a therapy dog has an impact on students’ stress and ability to pay attention in class. The students' heart rates were measured when the dog was present and when he was absent. The students were also asked to fill in a questionnaire. results showed no significant difference in the students’ average and maximum heart rates, between the experimental and control group, however the average resting heart rate was lower when the dog was present. The low resting heart rate coupled with written comments from the students in- dicate that the presence of the dog did reduce stress and had a calming effect on the students.peer-reviewe

Is transfusion in coronary artery surgery a predictor or a cause of reduced long-term survival?

Background Transfusion is common after coronary bypass surgery. Transfused patients present with higher operative risk and an increased hazard ratio for curtailed long-term survival. There is debate as to whether transfusion itself may further exacerbate late mortality. Methods Long-term survival was studied in 2550 survivors following coronary revascularization in this retrospective, observational study. Kaplan-Meier survival curves were constructed to compare all transfused and non-transfused patients, as well as survival in propensity-matched transfused and non-transfused patients. Results Operative mortality was 1.05% (original cohort 2577). Maximum follow-up was 23 years (mean 11.8, median 12.4 years). 34.7% of patients received a transfusion (mean 2 units packed red blood cells). Baseline risk characteristics (age, female gender, small body habitus, risk stratification scoring, diabetes, hypertension and reduced stroke volume) operative parameters (urgency and no internal thoracic graft) as well as post-operative parameters (intensive care, hospital stay and ventilation time) and complications (haemorrhage, intra-aortic balloon, ventricular arrhythmias, prolonged inotropic support, atrial fibrillation, dialysis, doubling of creatinine and resternotomy) were higher in the transfused patients. The long-term survival of these patients was significantly reduced when compared with that of non-transfused patients (log rank test p<0.001). When analyzed as a sole risk factor, transfusion was associated with reduced long-term survival (log rank test p<0.001) but when analyzed collectively with other risk factors, transfusion failed to demonstrate a causative effect (p=0.953). When propensity matched groups were compared (612 transfused versus 1222 non-transfused patients) long-term survival was similar (log rank test p=0.554). Conclusions Transfusion was required in higher risk patients undergoing coronary revascularization. Long-term survival was curtailed in this group but this was due to preoperative risk and not directly to transfusion. Transfusion was a predictor but not a cause of reduced long-term survival.peer-reviewe

A hybrid heuristic solving the traveling salesman problem

This paper presents a new hybrid heuristic for solving the Traveling Salesman Problem, The algorithm is designed on the frame of a general optimization procedure which acts upon two steps, iteratively. In first step of the global search, a feasible tour is constructed based on insertion approach. In the second step the feasible tour found at the first step, is improved by a local search optimization procedure. The second part of the paper presents the performances of the proposed heuristic algorithm, on several test instances. The statistical analysis shows the effectiveness of the local search optimization procedure, in the graphical representation.peer-reviewe

The dietary habits of Maltese university students

Objective: The objective of this study was to explore university students’ perceived diet and related health practices and whether these varied by gender, faculty and year of course. It also sought to examine the students’ recommendations on what may help them to engage in a healthier diet. Method: A self-administered questionnaire was completed by a representative sample of 494 undergraduate students stratified by gender and faculty. The questionnaire explored various features of the students’ perceived physical and mental health and lifestyle, including diet, the focus of this paper. Results: Half of the students had only between 1 and 2 servings of fruit and vegetables daily, more than half chose the less healthy food, less than half had a regular healthy breakfast, while one third consumed soft drinks. Female students were consistently more conscious of their diet. The students made various recommendations on how the university may help them to make healthy choices, particularly more availability of healthy food on campus. Conclusions: Despite being a highly educated group, the majority of students did not reach the healthy diet benchmarks explored in the study. Further research is suggested to explain the psychological correlates underlying the dietary habits of Maltese university students.peer-reviewe

Broad-spectrum antibiotic use in Europe : more evidence of cultural influences on prescribing behaviour

Objectives: Sociocultural factors have been hypothesized as important drivers of inappropriate antibiotic prescribing in European ambulatory care. This study sought to assess whether they can also explain the reported variation in broad-spectrum antibiotic (Br-Ab) use among EU/European Economic Area (EEA) countries. Methods: Correlation and regression analysis were performed, using the bootstrap method, between Br-Ab ratios reported from 28 EU countries by the ECDC, and national Hofstede cultural dimensions and control of corruption (CoC) scores. Results: Significant bootstrapping correlation coefficients were identified between Br-Ab ratios and the dimension of uncertainty avoidance (UAI) as well as CoC. However, following both bootstrapping multiple regression and generalized linear modelling, only UAI was retained as the sole predictor. A logarithmic model explained 58.6% of the variation in European Br-Ab variability solely using national UAI scores (P,0.001). Conclusions: Br-Ab prescribing appears to be driven by the level of UAI within the country. Any interventions aimed at reducing Br-Ab in high-consuming EU/EEA countries need to address this cultural perception to maxi-mize their chances of success.peer-reviewe

Bias of standard errors in latent class model applications using Newton-Raphson and EM algorithms

The EM algorithm is a popular method for computing maximum likelihood estimates. It tends to be numerically stable, reduces execution time compared to other estimation procedures and is easy to implement in latent class models. However, the EM algorithm fails to provide a consistent estimator of the standard errors of maximum likelihood estimates in incomplete data applications. Correct standard errors can be obtained by numerical differentiation. The technique requires computation of a complete-data gradient vector and Hessian matrix, but not those associated with the incomplete data likelihood. Obtaining first and second derivatives numerically is computationally very intensive and execution time may become very expensive when fitting Latent class models using a Newton-type algorithm. When the execution time is too high one is motivated to use the EM algorithm solution to initialize the Newton Raphson algorithm. We also investigate the effect on the execution time when a final Newton-Raphson step follows the EM algorithm after convergence. In this paper we compare the standard errors provided by the EM and Newton-Raphson algorithms for two models and analyze how this bias is affected by the number of parameters in the model fit.peer-reviewe

Factors related to fatigue in systemic lupus erythematosus : a cohort cross-sectional study

Background Fatigue is the most prevalent symptom in Systemic Lupus Erythematosus (SLE) as it is present in up to 90% of patients; it is considered to be the most disabling symptom in around half of the patients [1,2]. Its aetiology is multi-factorial and there is conflicting evidence on the relationship between fatigue and SLE disease activity, and between fatigue and vitamin D deficiency. The Ad Hoc Committee on Systemic Lupus Erythematosus Response Criteria for Fatigue recommended the Fatigue Severity Scale (FSS) for the measurement of fatigue in SLE [2,3].peer-reviewe

Estimation of ejection fraction with ventriculography versus echocardiography in patients referred for cardiac surgery

Abstract: Aim: The aim of this study was to compare the estimation of ejection fraction (EF) by ventricuography (VG) and echocardiography (ECHO) in patients referred for surgery and to validate the results by comparison with other published data. Methods: One hundred patients who underwent VG prior to surgery were subjected to a trans-thoracic ECHO. Radiographers calculated the EF by tracing the outer border of the ventriculogram during systole and diastole. A single cardiologist, who was blinded to the angiogram result, measured EF during trans-thoracic ECHO using the biplane Simpson’s method. Results: EF was significantly higher by VG versus ECHO for the whole group (67.9±13.2 vs 55.7±8.5, p=0.000). In 81 patients the EF estimated at VG was higher than that calculated at ECHO (71.7±10.2 vs 55.9±7.2, p=0.000). In 19 patients the EF estimated at VG was lower than that calculated at ECHO, but the difference was not significant (51.8±12.9 by VG vs 55.4±12.8, p=0.387). In 13 patients, with an EF less than 50% on VG, the correlation with ECHO was very good (42.0±9.0 vs 42.0±8.3, p=0.995). Two patients with an EF fraction under 30% had similar measurements by VG and ECHO. The EF range as measured by ECHO was consistent with published data. Conclusion: Ventriculography overestimates EF when compared with ECHO. When EF is less than 50% on VG, ECHO findings were similar. The value of ventriculography in patients referred for cardiac surgery is now being brought into question when ECHO, a better and less invasive test that measures EF, is available.peer-reviewe

Social, emotional and behaviour difficulties in Maltese schools

This paper reports the first national study of social, emotional and behaviour difficulties (SEBD) in Maltese schools. The study secured a sample of ten percent of the school population in state and non-state primary and secondary schools in Malta and Gozo, with 7000 students and their respective class teachers and parents selected to participate in the study. The study sought to explore the nature and distribution of SEBD in Maltese schools; to examine the relationships between SEBD and socio-cultural factors as reflected in the school, family and community contexts, and identify the risk and protective factors for SEBD. This paper presents the key findings of the study, and makes various recommendations in the prevention and management of SEBD and the promotion of socioemotional literacy in schools. A key message is the complexity and multi-factorial nature of this phenomenon, and the need for multilevel, multisystemic interventions.peer-reviewe