2 Minute Medicine Rewind April 16, 2018

Two-Year Outcomes with a Magnetically Levitated Cardiac Pump in Heart Failure

There are ongoing efforts to develop improved left ventricular assist systems that are more durable and associated with less pump thrombosis. An intrathoracic, fully magnetic, levitated centrifugal-flow pump has been designed to prevent pump thrombosis. In this randomized controlled trial, 366 individuals with advanced-stage heart failure were randomized to receive either a centrifugal-flow pump or an axial-flow pump. The primary outcome studied was a composite of survival at 2 years free of disabling stroke or free of reoperation for a malfunctioning device.  Researchers found that at 2 years of follow-up, patients in the centrifugal-flow pump group were less likely to have experienced disabling stroke or require reoperation compared to patients in the axial-flow pump (HR 0.46, 95% CI 0.31 to 0.69). The rates of death and disabling stroke were similar between groups, and as such, the difference in primary outcome was mainly driven by the difference in rate of reoperation or device removal. Importantly, however, the overall rate of stroke was significantly lower in the centrifugal-flow pump group (HR 0.47, 95% CI 0.27 to 0.84). In terms of adverse events, pump thrombosis occurred in 1.1% of the centrifugal-flow pump group and 15.7% in the axial-flow pump group (HR 0.06, 95% CI 0.01 to 0.26, p<0.001). Taken together, results indicate that the centrifugal-flow pump is associated with significantly increased survival free of stroke or reoperation compared to axial-flow devices.

Association of Whole-Body Computed Tomography With Mortality Risk in Children With Blunt Trauma

It is currently unclear whether the benefits of using whole-body computed tomography (CT) for children with trauma-related injuries exceed the risks associated with exposure to ionizing radiation. In this retrospective cohort study, investigators analyzed records on 42,912 children with blunt trauma in order to compare in-hospital mortality during the 7 days after arrival to the emergency department (ED) in children who received whole-body CT (WBCT) versus selective CT. Researchers found that 0.9% of children overall died within the first 7 days from ED arrival, with mortality varying by mechanism of trauma. Unadjusted analyses showed that children who received WBCT had a significantly higher risk of death compared with those who received selective CT (RR 5.0, 95% CI 4.1 to 6.1), in keeping with the fact that children who receive WBCT are more likely to be severely injured. As such, investigators adjusted for potential confounding by creating a propensity model to make WBCT and selective CT groups more similar. Further analysis showed that there was no significant difference between the WBCT and selective CT groups (RR 0.8, 95% CI 0.6 to 1.1). Overall, this study found no evidence to support that WBCT is associated with lower mortality compared to selective CT, and therefore, does not support the routine use of WBCT for children with blunt trauma. This study is limited in that there may have been other confounders that the propensity model did not adjust for.

Zika Virus Shedding in Semen of Symptomatic Infected Men

Zika virus has been found to be sexually transmissible. The frequency, duration, and pattern of viral shedding in semen, however, has not been well studied. In this prospective cohort study, investigators studied 225 men with confirmed, symptomatic Zika virus infection to identify risk factors for prolonged shedding in semen and urine. Researchers found that 33% of participants had at least one sample positive for Zika virus RNA between 14 and 304 days after illness onset. Based on samples submitted within 30 days after illness onset, 61% of men had detectable viral RNA in their semen. Only 7% or less of men had detectable viral loads at 90 days. Only 1% of urine samples showed positive RNA results on RT-PCR, with a maximum level of 4.6 log10 RNA copies/mL. Overall, analysis of results yielded an estimation that only 5% of men would have detectable Zika virus RNA levels by 158 days after the onset of symptoms (upper limit of 95% CI 186 days) and only 1% of men would have detectable levels by 240 days (upper limit 95% CI 299 days). Risk factors associated with longer time to RNA clearance from semen included increasing age (p=0.01), presence of conjunctivitis (p=0.02), absence of joint pain (p=0.003), and less frequent ejaculation (p=0.002). This study therefore shows that Zika viral RNA can be found in semen up to 6 months after the onset of illness. It is important to note, however, that this study was not designed to study the correlation between sexual transmission and detectable viral RNA load, and also did not study asymptomatic men.

Effectiveness of a long-lasting piperonyl butoxide-treated insecticidal net and indoor residual spray interventions, separately and together, against malaria transmitted by pyrethroid-resistant mosquitoes: a cluster, randomised controlled, two-by-two factorial design trial

Recent wide-scale selection of insecticide resistance in mosquito vectors across Africa necessitates new tools and strategies to control mosquito vectors as part of reducing mortality due to malaria. Currently, the World Health Organization (WHO) recommends only the pyrethroid class of insecticides for long-lasting nets, but a new net using piperonyl butoxide (PBO) has been developed. In this randomized controlled trial, investigators randomized participants in 40 villages (29,365 households for a total population of 135,900) to either PBO long-lasting insecticidal nets or standard nets with or without indoor residual spraying. The primary outcome measured was the prevalence of Plasmodium spp infection in children age 6 months to 14 years assessed by cross-sectional survey at 4, 9, 16 and 21 months after the intervention. Researchers found that there was no significant difference between PBO long-lasting insecticidal nets or standard nets at 4 months (p=0.1630), however results at 9 months showed that the prevalence of malaria was significantly decreased in the intervention group in comparison to standard nets (OR 0.37, 95% CI 0.21 to 0.65, p=0.0011), Indoor residual spraying also reduced the prevalence of malaria in comparison to no spraying at 9 months (OR 0.33, 95% CI 0.19 to 0.55, p<0.0001). PBO nets were also associated with a lower prevalence of malaria infection at 16 and 21 months compared to the standard nets (OR 0.47, 95% CI 0.26 to 0.87, p=0.0173 and OR 0.40, 95% CI 0.20 to 0.81, p=0.0122), although the benefit of indoor residual spraying declined over time (OR at 21 months 0.58, 95% CI 0.29 to 1.14). Overall, the results of this study indicate that the use of PBO nets can help reduce malaria infection in areas where there is resistance to pyrethroid insecticides. This study, however, was not sufficiently powered to detect all interactions between different types of net and indoor residual spraying. Further studies are required in identifying redundancy between different strategies.

Effect of ready-to-use supplementary food on mortality in severely immunocompromised HIV-infected individuals in Africa initiating antiretroviral therapy (REALITY): an open-label, parallel-group, randomised controlled trial

Macronutrient and micronutrient undernutrition commonly affects individuals infected with HIV in sub-Saharan Africa. It has been hypothesized that improving nutrition may improve outcomes for these individuals when they are treated with anti-retroviral therapy (ART). In this randomized controlled study, investigators randomized 1805 individuals with confirmed HIV infection and a CD4 cell count <100 cells/uL to initiate ART with or without universal provision of 12 weeks of peanut-based ready-to-use supplementary food (RUSF), in order to study the effect of having RUSF on all-cause mortality at 24 weeks. In both groups, participants identified as malnourished were referred to local nutrition programs for ready-to-use therapeutic food. Researchers found mortality at 24 weeks was comparable between groups, where 10.9% (95% CI 9.0% to 13.1%) of participants allocated to RUSF died compared to 10.3% (95% CI 8.5% to 12.5%) of those allocated to no-RUSF (HR 1.05, 95% CI 0.79 to 1.40, p=0.75). Self-reported ART adherence did not significantly differ between the two groups (p=0.81), and there were no differences between groups at any time points in terms of viral suppression. Overall, the results of this study indicate that universal provision of RUSF does not reduce early mortality, change viral suppression, or improve ART adherence.

Image: PD

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