The impact of extracorporeal membrane oxygenation on mortality in patients with cardiogenic shock post-acute myocardial infarction: a systematic review and meta-analysis

Aims

Cardiogenic shock remains the leading cause of death in patients hospitalized with acute myocardial infarction. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used in the treatment of infarct-related cardiogenic shock. However, there is limited evidence regarding its beneficial impact on mortality. The aim of this study was to systematically review studies reporting the impact of VA-ECMO on mortality in patients with acute myocardial infarction complicated by cardiogenic shock.

Methods and results

A comprehensive search of medical databases (Cochrane Register and PubMed) was conducted. Studies that reported mortality outcomes in patients treated with VA-ECMO for infarct-related cardiogenic shock were included. The database search yielded 1194 results, of which 11 studies were included in the systematic review. Four of these studies, with a total of 586 patients, were randomized controlled trials and were included in the meta-analysis. This demonstrated that there was no significant difference in 30-day all-cause mortality with the use of VA-ECMO compared with standard medical therapy [odds ratio (OR) 0.91; 95% confidence interval (CI) 0.65-1.27]. Meta-analysis of two studies showed that VA-ECMO was associated with a significant reduction in 12-month all-cause mortality (OR 0.31; 95% CI 0.11-0.86). Qualitative synthesis of the observational studies showed that age, serum creatinine, serum lactate, and successful revascularization are independent predictors of mortality.

Conclusion

Veno-arterial extracorporeal membrane oxygenation does not improve 30-day all-cause mortality in patients with cardiogenic shock following acute myocardial infarction; however, there may be significant reduction in all-cause mortality at 12 months. Further studies are needed to delineate the potential benefit of VA-ECMO in long-term outcomes.

Registration

The protocol was registered in the PROSPERO International Prospective Register of Systematic Reviews (ID: CRD42023461740).

Circumferential resection margin positivity due to direct or indirect tumour involvement in rectal cancer - a call for better stratification

BACKGROUND

A positive circumferential resection margin (CRM) after rectal cancer surgery, which can be the result of direct or indirect tumour involvement, has consistently been associated with increased local recurrence and poorer survival. However, little is known of the differential impact of the mode of tumour involvement on outcomes.

METHODS

1460 consecutive patients undergoing rectal cancer resection between 2003 and 2018 were retrospectively assessed. Histopathology reports for patients with a positive CRM were reviewed to determine cases of direct (R1-tumour) or indirect tumour involvement (R1-other). Disease-free survival (DFS) and overall survival (OS) were assessed by Kaplan-Meier analysis. The role of the mode of CRM positivity was examined by univariate and multivariate Cox proportional hazards models.

RESULTS

Eighty-five patients had an R1 resection due to CRM involvement (5.8%). Of those, 69 were due to direct tumour involvement, while 16 were from indirect causes. Kaplan-Meier analysis revealed that R1-other was associated with increased OS (hazard ratio 0.40, log-rank P = 0.006) and DFS (P = 0.043). Multivariate regression confirmed that the mode of CRM positivity was an independent predictor of OS. More interestingly, the patterns of recurrence were different between the two groups, with R1-tumour leading to significantly more local recurrence (P = 0.04).

CONCLUSIONS

Our data strongly suggests that direct tumour involvement of the CRM confers worse prognosis after rectal cancer surgery. Importantly, differences in the site and frequency of recurrences make a case for better stratification of patients with a positive CRM to guide treatment decisions.

Drug coated balloons for coronary artery bifurcation lesions: A systematic review and focused meta-analysis

Objectives

We sought to systematically review the evidence supporting the role of drug coated balloons (DCBs) in the treatment of coronary bifurcation lesions.

Background

DCBs are emerging as an attractive alternative treatment strategy for treating coronary bifurcations due to simplifying the approach and reducing rates of stent related complications. We systematically reviewed the evidence for DCB use in coronary bifurcations and conducted a focused meta-analysis on late lumen loss in the side branch comparing DCB and plain old balloon angioplasty (POBA).

Methods

This study was conducted in line with the PRISMA statement. All studies (including both RCTs and observational studies, excluding case reports) using DCB as part of a bifurcation strategy were included in this review. A literature search identified a total of ten studies for inclusion. A focused meta-analysis was undertaken for the use of DCB in side-branch compared with POBA. Mean late lumen loss was used with a random effects model due to heterogeneity.

Results

DCB was found to be superior to POBA for side branch treatment in bifurcations (p = 0.01). There are four studies that investigated the use of DCB for main branch treatment in a bifurcation, with evidence supporting its safety in main branches of bifurcation lesions, while prospective observational studies have demonstrated favourable target lesion revascularisation rates.

Conclusion

Although there is a lack of robust RCTs comparing DCBs with current generation DES, DCBs appear safe in main branch bifurcation lesions with improved side branch late lumen loss when compared with DES or POBA.

Clinical Translation of Three-Dimensional Scar, Diffusion Tensor Imaging, Four-Dimensional Flow, and Quantitative Perfusion in Cardiac MRI: A Comprehensive Review

Cardiovascular magnetic resonance (CMR) imaging is a versatile tool that has established itself as the reference method for functional assessment and tissue characterisation. CMR helps to diagnose, monitor disease course and sub-phenotype disease states. Several emerging CMR methods have the potential to offer a personalised medicine approach to treatment. CMR tissue characterisation is used to assess myocardial oedema, inflammation or thrombus in various disease conditions. CMR derived scar maps have the potential to inform ablation therapy—both in atrial and ventricular arrhythmias. Quantitative CMR is pushing boundaries with motion corrections in tissue characterisation and first-pass perfusion. Advanced tissue characterisation by imaging the myocardial fibre orientation using diffusion tensor imaging (DTI), has also demonstrated novel insights in patients with cardiomyopathies. Enhanced flow assessment using four-dimensional flow (4D flow) CMR, where time is the fourth dimension, allows quantification of transvalvular flow to a high degree of accuracy for all four-valves within the same cardiac cycle. This review discusses these emerging methods and others in detail and gives the reader a foresight of how CMR will evolve into a powerful clinical tool in offering a precision medicine approach to treatment, diagnosis, and detection of disease.

The Analysis of Teaching of Medical Schools (AToMS) survey: an analysis of 47,258 timetabled teaching events in 25 UK medical schools relating to timing, duration, teaching formats, teaching content, and problem-based learning

BACKGROUND

What subjects UK medical schools teach, what ways they teach subjects, and how much they teach those subjects is unclear. Whether teaching differences matter is a separate, important question. This study provides a detailed picture of timetabled undergraduate teaching activity at 25 UK medical schools, particularly in relation to problem-based learning (PBL).

METHOD

The Analysis of Teaching of Medical Schools (AToMS) survey used detailed timetables provided by 25 schools with standard 5-year courses. Timetabled teaching events were coded in terms of course year, duration, teaching format, and teaching content. Ten schools used PBL. Teaching times from timetables were validated against two other studies that had assessed GP teaching and lecture, seminar, and tutorial times.

RESULTS

A total of 47,258 timetabled teaching events in the academic year 2014/2015 were analysed, including SSCs (student-selected components) and elective studies. A typical UK medical student receives 3960 timetabled hours of teaching during their 5-year course. There was a clear difference between the initial 2 years which mostly contained basic medical science content and the later 3 years which mostly consisted of clinical teaching, although some clinical teaching occurs in the first 2 years. Medical schools differed in duration, format, and content of teaching. Two main factors underlay most of the variation between schools, Traditional vs PBL teaching and Structured vs Unstructured teaching. A curriculum map comparing medical schools was constructed using those factors. PBL schools differed on a number of measures, having more PBL teaching time, fewer lectures, more GP teaching, less surgery, less formal teaching of basic science, and more sessions with unspecified content.

DISCUSSION

UK medical schools differ in both format and content of teaching. PBL and non-PBL schools clearly differ, albeit with substantial variation within groups, and overlap in the middle. The important question of whether differences in teaching matter in terms of outcomes is analysed in a companion study (MedDifs) which examines how teaching differences relate to university infrastructure, entry requirements, student perceptions, and outcomes in Foundation Programme and postgraduate training.

Exploring UK medical school differences: the MedDifs study of selection, teaching, student and F1 perceptions, postgraduate outcomes and fitness to practise

BACKGROUND

Medical schools differ, particularly in their teaching, but it is unclear whether such differences matter, although influential claims are often made. The Medical School Differences (MedDifs) study brings together a wide range of measures of UK medical schools, including postgraduate performance, fitness to practise issues, specialty choice, preparedness, satisfaction, teaching styles, entry criteria and institutional factors.

METHOD

Aggregated data were collected for 50 measures across 29 UK medical schools. Data include institutional history (e.g. rate of production of hospital and GP specialists in the past), curricular influences (e.g. PBL schools, spend per student, staff-student ratio), selection measures (e.g. entry grades), teaching and assessment (e.g. traditional vs PBL, specialty teaching, self-regulated learning), student satisfaction, Foundation selection scores, Foundation satisfaction, postgraduate examination performance and fitness to practise (postgraduate progression, GMC sanctions). Six specialties (General Practice, Psychiatry, Anaesthetics, Obstetrics and Gynaecology, Internal Medicine, Surgery) were examined in more detail.

RESULTS

Medical school differences are stable across time (median alpha = 0.835). The 50 measures were highly correlated, 395 (32.2%) of 1225 correlations being significant with p < 0.05, and 201 (16.4%) reached a Tukey-adjusted criterion of p < 0.0025. Problem-based learning (PBL) schools differ on many measures, including lower performance on postgraduate assessments. While these are in part explained by lower entry grades, a surprising finding is that schools such as PBL schools which reported greater student satisfaction with feedback also showed lower performance at postgraduate examinations. More medical school teaching of psychiatry, surgery and anaesthetics did not result in more specialist trainees. Schools that taught more general practice did have more graduates entering GP training, but those graduates performed less well in MRCGP examinations, the negative correlation resulting from numbers of GP trainees and exam outcomes being affected both by non-traditional teaching and by greater historical production of GPs. Postgraduate exam outcomes were also higher in schools with more self-regulated learning, but lower in larger medical schools. A path model for 29 measures found a complex causal nexus, most measures causing or being caused by other measures. Postgraduate exam performance was influenced by earlier attainment, at entry to Foundation and entry to medical school (the so-called academic backbone), and by self-regulated learning. Foundation measures of satisfaction, including preparedness, had no subsequent influence on outcomes. Fitness to practise issues were more frequent in schools producing more male graduates and more GPs.

CONCLUSIONS

Medical schools differ in large numbers of ways that are causally interconnected. Differences between schools in postgraduate examination performance, training problems and GMC sanctions have important implications for the quality of patient care and patient safety.

Effectiveness of Digital Education on Communication Skills Among Medical Students: Systematic Review and Meta-Analysis by the Digital Health Education Collaboration

Background

Effective communication skills are essential in diagnosis and treatment processes and in building the doctor-patient relationship.

Objective

Our aim was to evaluate the effectiveness of digital education in medical students for communication skills development. Broadly, we assessed whether digital education could improve the quality of future doctors’ communication skills.

Methods

We performed a systematic review and searched seven electronic databases and two trial registries for randomized controlled trials (RCTs) and cluster RCTs (cRCTs) published between January 1990 and September 2018. Two reviewers independently screened the citations, extracted data from the included studies, and assessed the risk of bias. We also assessed the quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluations assessment (GRADE).

Results

We included 12 studies with 2101 medical students, of which 10 were RCTs and two were cRCTs. The digital education included online modules, virtual patient simulations, and video-assisted oral feedback. The control groups included didactic lectures, oral feedback, standard curriculum, role play, and no intervention as well as less interactive forms of digital education. The overall risk of bias was high, and the quality of evidence ranged from moderate to very low. For skills outcome, meta-analysis of three studies comparing digital education to traditional learning showed no statistically significant difference in postintervention skills scores between the groups (standardized mean difference [SMD]=–0.19; 95% CI –0.9 to 0.52; I²=86%, N=3 studies [304 students]; small effect size; low-quality evidence). Similarly, a meta-analysis of four studies comparing the effectiveness of blended digital education (ie, online or offline digital education plus traditional learning) and traditional learning showed no statistically significant difference in postintervention skills between the groups (SMD=0.15; 95% CI –0.26 to 0.56; I²=86%; N=4 studies [762 students]; small effect size; low-quality evidence). The additional meta-analysis of four studies comparing more interactive and less interactive forms of digital education also showed little or no difference in postintervention skills scores between the two groups (SMD=0.12; 95% CI: –0.09 to 0.33; I²=40%; N=4 studies [893 students]; small effect size; moderate-quality evidence). For knowledge outcome, two studies comparing the effectiveness of blended online digital education and traditional learning reported no difference in postintervention knowledge scores between the groups (SMD=0.18; 95% CI: –0.2 to 0.55; I²=61%; N=2 studies [292 students]; small effect size; low-quality evidence). The findings on attitudes, satisfaction, and patient-related outcomes were limited or mixed. None of the included studies reported adverse outcomes or economic evaluation of the interventions.

Conclusions

We found low-quality evidence showing that digital education is as effective as traditional learning in medical students’ communication skills training. Blended digital education seems to be at least as effective as and potentially more effective than traditional learning for communication skills and knowledge. We also found no difference in postintervention skills between more and less interactive forms of digital education. There is a need for further research to evaluate the effectiveness of other forms of digital education such as virtual reality, serious gaming, and mobile learning on medical students’ attitude, satisfaction, and patient-related outcomes as well as the adverse effects and cost-effectiveness of digital education.

Association of Vpu-binding protein with microtubules and Vpu-dependent redistribution of HIV-1 Gag protein

The efficient exit of HIV-1 particles from cells requires the action of the viral encoded protein Vpu. Vpu-binding protein (Ubp) is a cellular protein that interacts with both Vpu and the major structural component of the viral capsid (Gag) and appears to affect the efficiency of particle exit. Elucidation of the function of Ubp and characterization of the spatial distribution of Ubp may provide information pertinent to understanding the role of Ubp in virus replication. To investigate the subcellular location of Ubp, and to see whether Vpu affects the intracellular distribution of Gag, we carried out immunofluorescence localization in conjunction with confocal microscopy. Based on this analysis Ubp is present in both the nucleus and the cytoplasm. In the cytoplasm, Ubp appeared to be associated with microtubules as evidenced by cofluorescence with tubulin in the absence and in the presence of colchicine. However, cytoskeletal isolation and detergent extraction of cells resulted in association of Ubp with the soluble fractions, indicating that Ubp is not in tight association with microtubules. Moreover, flotation gradient analysis demonstrated that Ubp is cytoplasmic and not stably associated with the plasma membrane. Interestingly, expression of Vpu in cells resulted in redistribution of both Ubp and Gag to a location near the periphery of the cell. The effect of Vpu on both Ubp and Gag protein has implications for Vpu-mediated particle exit from cells.

A national survey of care for persons with co-occurring mental and substance use disorders

OBJECTIVE

The delivery of appropriate treatment to persons who have mental and substance use disorders is of increasing concern to clinicians, administrators, and policy makers. This study sought to describe use of appropriate mental health and comprehensive substance abuse care among adults in the United States with probable co-occurring disorders.

METHODS

Data from the Healthcare for Communities survey, which is based on a national household sample studied in 1997 and 1998, were used to identify individuals who had probable co-occurring mental and substance use disorders. The sociodemographic and clinical characteristics of these individuals and their use of services were recorded. Logistic regression analysis was used to identify variables associated with receipt of mental health and substance abuse treatment and with receipt of appropriate treatment.

RESULTS

Estimates for the U.S. adult population based on the weighted survey data indicated that 3 percent of the population had co-occurring disorders. Seventy-two percent did not receive any specialty mental health or substance abuse treatment in the previous 12 months; only 8 percent received both specialty mental health care and specialty substance abuse treatment. Only 23 percent received appropriate mental health care, and 9 percent received supplemental substance abuse treatment. Perceived need for treatment was strongly associated with receipt of any mental health care and with receipt of appropriate care.

CONCLUSIONS

Despite the availability of effective treatments, most individuals who had co-occurring mental health and substance use problems were not receiving effective treatment. Efforts to improve the care provided to persons who have co-occurring disorders should focus on strategies that increase the delivery of effective treatment.

Testing for the BRCA1 and BRCA2 breast-ovarian cancer susceptibility genes: a decision analysis

OBJECTIVE

The authors developed a Markov decision model to evaluate the health implications of testing for mutations in the BRCA1 and BRCA2 breast-ovarian cancer susceptibility genes. Prophylactic measures considered included various combinations of immediate and delayed bilateral mastectomy and oophorectomy or taking no action.

METHODS

The model incorporated the likelihood of developing breast and/or ovarian cancer, survival, and quality of life. Parameter values were taken from public databases, the published literature, and a survey of cancer experts. Outcomes considered were additional life expectancy and quality-adjusted life years (QALYs). Results are reported for 30-year-old cancer-free women at various levels of hereditary risk.

RESULTS AND CONCLUSIONS

The vast majority of women will not benefit from testing because their pre-test risks are low and surgical prophylaxis is undesirable. However, women who have family histories of early breast and/or ovarian cancer may gain up to 2 QALYs by allowing genetic testing to inform their decisions.

Expression pattern of a butterfly achaete-scute homolog reveals the homology of butterfly wing scales and insect sensory bristles

BACKGROUND

Lepidopteran wing scales are the individual units of wing color patterns and were a key innovation during Lepidopteran evolution. On the basis of developmental and morphological evidence, it has been proposed that the sensory bristles of the insect peripheral nervous system and the wing scales of Lepidoptera are homologous structures. In order to determine if the developmental pathways leading to Drosophila sensory bristle and butterfly scale formation use similar genetic circuitry, we cloned, from the butterfly Precis coenia, a homolog of the Drosophila achaete-scute (AS-C) genes--which encode transcription factors that promote neural precursor formation--and examined its expression pattern during development.

RESULTS

During embryonic and larval development, the expression pattern of the AS-C homolog, ASH1, forecasted neural precursor formation. ASH1 was expressed both in embryonic proneural clusters--within which an individual cell retained ASH1 expression, enlarged, segregated, and became a neural precursor--and in larval wing discs in putative sensory mother cells. ASH1 was also expressed in pupal wings, however, in evenly spaced rows of enlarged cells that had segregated from the underlying epidermis but, rather than give rise to neural structures, each cell contributed to an individual scale.

CONCLUSIONS

ASH1 appears to perform multiple functions throughout butterfly development, apparently promoting the initial events of selection and formation of both neural and scale precursor cells. The similarity in the cellular and molecular processes of scale and neural precursor formation suggests that the spatial regulation of an AS-C gene was modified during Lepidopteran evolution to promote scale cell formation.

Morphing: a new graphics tool for animating confocal images

The application of morphing to the display of developmental processes is described. This new graphics tool imparts the dynamic aspects of time-lapse microscopy to a series of fixed and stained images of a developing system. The technique is illustrated using confocal images of wing imaginal discs of Drosophila. It is anticipated that morphing can be applied not only to the display and analysis of developing systems but also to the elucidation of evolutionary relationships between species and to comparative anatomy.

Improved detection of in situ hybridization by laser scanning confocal microscopy

Laser scanning confocal microscopy (LSCM) offers a significant improvement over conventional bright-field and dark-field light microscopy for producing images of silver grains in autoradiograms of specimens prepared by in situ hybridization. The out-of-focus image of the background silver grains present in the emulsion is eliminated from the in-focus image of the radioactive probe associated with the cells by optical sectioning with the LSCM operated in a reflected light mode. The improved images produced by the LSCM provide a significant increase in the sensitivity of detecting positively labeled cells and tissues prepared by in situ hybridization. The power of this detection method is demonstrated using samples of HIV-infected human peripheral blood cells, tissue sections of human placenta and human skin. It is anticipated that the method can be universally applied to samples prepared by in situ hybridization techniques.

Three-dimensional imaging of fertilization and early development

The field of biological microscopy has recently enjoyed major technical advances, exemplified by the development of field-emission low-voltage scanning electron microscopes and laser scanning confocal light microscopes. In addition, computer processing of microscopical data is revolutionizing the way morphological information is imaged. In this paper, we illustrate methods by which this new technology can be used to examine events in fertilization and early development in three dimensions. Different types of specimen preparation protocols, using both echinoderm and mammalian gametes and embryos, are evaluated for their ability to preserve accurately the three-dimensional organization of these specimens for imaging by both low-voltage scanning electron microscopy and laser scanning confocal light microscopy.

Localization of human growth hormone to a sub-set of cytoplasmic vesicles in transfected PC12 cells

Two distinct population of vesicles can be identified in PC12 cells by subcellular fractionation and immunofluorescence. Density gradient separation reveals one population of dense vesicles that contains the transgenic regulated secretory protein hGH (human growth hormone) along with the endogenous neurotransmitter norepinephrine. Some of the neuronal vesicle marker synaptophysin (P38) is also associated with these vesicles. A second population of low-density vesicles contains synaptophysin but not hGH or norepinephrine. Immunofluorescence localization of hGH revealed a pattern consistent with packaging into catecholaminergic vesicles: the staining is punctate and most concentrated in the tips of the neuritic processes, with secondary accumulation in the perinuclear region. Double-staining of cells for hGH and synaptophysin confirms that these proteins do not co-localize but rather are spatially segregated within the cell. The observed distribution of vesicle markers is inconsistent with simple models for the generation of one type of vesicle from the other, suggesting that the vesicles are products of two divergent biosynthetic pathways. While the hGH is clearly contained in regulated secretory vesicles, the function of the second population of vesicles remains uncertain.

In vitro confocal imaging of the rabbit cornea

We were able to observe in vitro the fine structure of the rabbit cornea using a laser scanning confocal microscope, especially in the regions between Descemet's membrane and the epithelial basal lamina. We observed submicrometre filaments throughout the stroma with high concentrations adjacent to Descemet's membrane, and found extensive interconnecting processes between stromal keratocytes. There are numerous regions containing nerve plexuses in the stroma. We found a deeply convoluted basal lamina adjacent to the epithelium, and observed regions containing junctions between endothelial cells in fluorescent images of rabbit corneas stained with the actin-specific compound fluorescein phalloidin.