Findings of the International Subarachnoid Aneurysm Trial and the National Study of Subarachnoid Haemorrhage in context.

Concern has been expressed about the applicability of the findings of the International Subarachnoid Aneurysm Trial (ISAT) with respect to the relative effects on outcome of coiling and clipping. It has been suggested that the findings of the National Study of Subarachnoid Haemorrhage may have greater relevance for neurosurgical practice. The objective of this paper was to interpret the findings of these two studies in the context of differences in their study populations, design, execution and analysis. Because of differences in design and analysis, the findings of the two studies are not directly comparable. The ISAT analysed all randomized patients by intention-to-treat, including some who did not undergo a repair, and obtained the primary outcome for 99% of participants. The National Study only analysed participants who underwent clipping or coiling, according to the method of repair, and obtained the primary outcome for 91% of participants. Time to repair was also considered differently in the two studies. The comparison between coiling and clipping was susceptible to confounding in the National Study, but not in the ISAT. The two study populations differed to some extent, but inspection of these differences does not support the view that coiling was applied inappropriately in the National Study. Therefore, there are many reasons why the two studies estimated different sizes of effect. The possibility that there were real, systematic differences in practice between the ISAT and the National Study cannot be ruled out, but such explanations must be seen in the context of other explanations relating to chance, differences in design or analysis, or confounding

A review of the tractive performance of wheeled tractors and soil management in lowland intensive rice production.

This paper reviews the cultivation practices and tractive performance using wheeled tractors, and how these interact with soil management, in lowland intensive rice production. The paper explores the issues of long term sustainable soil use, the energy inputs required, environmental impact and changes in approach to agronomy and links these to the tractor operations carried out as part of rice production. The paddy soil environment demonstrates very significant changes in soil properties with depth, in particular soil density, penetrometer resistance, soil structure and pore interconnectivity, water content and movement, and soil biology. This is related to the management of the soil hard pan in relation to machinery operations and machinery use. One of the issues appears to be that the hard pan can be deeper than required with consequently unnecessarily high energy inputs. The tractive performance of wheeled tractors on different surface conditions is considered with respect to tractive efficiency and maintenance of a soil hard pan that has the required characteristics for sustainable production. Alternatives to conventional tyres, cage wheels and tracks, are considered. The cultivation operations are evaluated in relation to soil management, crop requirements and energy use. Variation in hard pan characteristics may be disadvantageous and provides opportunities for precision operations

Modeling the Effects of Low Flow Augmentation by Discharge from a Wastewater Treatment Plant on Dissolved Oxygen Concentration in Leon Creek, San Antonio, Texas.

A GIS-based hydrological/water quality model called Non Point Source Model (NPSM) was used to simulate various physical, chemical and biological processes taking place in the Leon Creek Watershed, near San Antonio, Texas. The model was then used to evaluate base flow augmentation scenarios to remedy dissolved oxygen problems during dry, low-flow periods. The effects were demonstrated by increasing base flow in a stream by discharging recycled water from Leon Creek Wastewater Treatment Plant during a three month low-flow period in 1993, 1994 and 1995 respectively. Five scenarios were evaluated in addition to the control scenario (no flow augmentation). Each of the five scenarios represented an increase in base flow by a factor of 0.25, 0.5, 1, 2 and 4 respectively. The study indicated that increasing base flow in the stream increased the mean daily DO concentration in the stream. The most significant effect was observed when the base flow was increased by a factor of 1 onwards, with no data point falling below the DO criterion of 5 mg/l. From the results of DO modeling developed for this project iv and from the scenario analysis, it can be concluded that a minimum flow augmentation of one times base flow (i.e. doubling the base flow) is required in order to see a significant increase in mean daily DO concentration in Leon Creek and associated tributaries and remedy DO problems during low-flow periods. Since there is uncertainty involved in the modeling process, it is recommended that a higher flow augmentation of two times base flow or four times base flow be implemented in order to reduce uncertainty and significantly improve water quality of Leon Creek

Update on the Surgical Trial in Lobar Intracerebral Haemorrhage (STICH II):Statistical analysis plan

<p>Abstract</p> <p>Background</p> <p>Previous studies had suggested that the outcome for patients with spontaneous lobar intracerebral haemorrhage (ICH) and no intraventricular haemorrhage (IVH) might be improved with early evacuation of the haematoma. The Surgical Trial in Lobar Intracerebral Haemorrhage (STICH II) set out to establish whether a policy of earlier surgical evacuation of the haematoma in selected patients with spontaneous lobar ICH would improve outcome compared to a policy of initial conservative treatment. It is an international, multi-centre, prospective randomised parallel group trial of early surgery in patients with spontaneous lobar ICH. Outcome is measured at six months via a postal questionnaire.</p> <p>Results</p> <p>Recruitment to the study began on 27 November 2006 and closed on 15 August 2012 by which time 601 patients had been recruited. The protocol was published in <it>Trials</it> (<url>http://www.trialsjournal.com/content/12/1/124/</url>). This update presents the analysis plan for the study without reference to the unblinded data. The trial data will not be unblinded until after follow-up is completed in early 2013. The main trial results will be presented in spring 2013 with the aim to publish in a peer-reviewed journal at the same time.</p> <p>Conclusion</p> <p>The data from the trial will provide evidence on the benefits and risks of early surgery in patients with lobar ICH.</p> <p>Trial registration</p> <p>ISRCTN: ISRCTN22153967</p

Length of carotid stenosis predicts peri-procedural stroke or death and restenosis in patients randomized to endovascular treatment or endarterectomy.

BACKGROUND: The anatomy of carotid stenosis may influence the outcome of endovascular treatment or carotid endarterectomy. Whether anatomy favors one treatment over the other in terms of safety or efficacy has not been investigated in randomized trials. METHODS: In 414 patients with mostly symptomatic carotid stenosis randomized to endovascular treatment (angioplasty or stenting; n = 213) or carotid endarterectomy (n = 211) in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), the degree and length of stenosis and plaque surface irregularity were assessed on baseline intraarterial angiography. Outcome measures were stroke or death occurring between randomization and 30 days after treatment, and ipsilateral stroke and restenosis ≥50% during follow-up. RESULTS: Carotid stenosis longer than 0.65 times the common carotid artery diameter was associated with increased risk of peri-procedural stroke or death after both endovascular treatment [odds ratio 2.79 (1.17-6.65), P = 0.02] and carotid endarterectomy [2.43 (1.03-5.73), P = 0.04], and with increased long-term risk of restenosis in endovascular treatment [hazard ratio 1.68 (1.12-2.53), P = 0.01]. The excess in restenosis after endovascular treatment compared with carotid endarterectomy was significantly greater in patients with long stenosis than with short stenosis at baseline (interaction P = 0.003). Results remained significant after multivariate adjustment. No associations were found for degree of stenosis and plaque surface. CONCLUSIONS: Increasing stenosis length is an independent risk factor for peri-procedural stroke or death in endovascular treatment and carotid endarterectomy, without favoring one treatment over the other. However, the excess restenosis rate after endovascular treatment compared with carotid endarterectomy increases with longer stenosis at baseline. Stenosis length merits further investigation in carotid revascularisation trials

Early surgery versus initial conservative treatment in patients with spontaneous supratentorial lobar intracerebral haematomas (STICH II):a randomised trial

SummaryBackgroundThe balance of risk and benefit from early neurosurgical intervention for conscious patients with superficial lobar intracerebral haemorrhage of 10–100 mL and no intraventricular haemorrhage admitted within 48 h of ictus is unclear. We therefore tested the hypothesis that early surgery compared with initial conservative treatment could improve outcome in these patients.MethodsIn this international, parallel-group trial undertaken in 78 centres in 27 countries, we compared early surgical haematoma evacuation within 12 h of randomisation plus medical treatment with initial medical treatment alone (later evacuation was allowed if judged necessary). An automatic telephone and internet-based randomisation service was used to assign patients to surgery and initial conservative treatment in a 1:1 ratio. The trial was not masked. The primary outcome was a prognosis-based dichotomised (favourable or unfavourable) outcome of the 8 point Extended Glasgow Outcome Scale (GOSE) obtained by questionnaires posted to patients at 6 months. Analysis was by intention to treat. This trial is registered, number ISRCTN22153967.Findings307 of 601 patients were randomly assigned to early surgery and 294 to initial conservative treatment; 298 and 291 were followed up at 6 months, respectively; and 297 and 286 were included in the analysis, respectively. 174 (59%) of 297 patients in the early surgery group had an unfavourable outcome versus 178 (62%) of 286 patients in the initial conservative treatment group (absolute difference 3·7% [95% CI −4·3 to 11·6], odds ratio 0·86 [0·62 to 1·20]; p=0·367).InterpretationThe STICH II results confirm that early surgery does not increase the rate of death or disability at 6 months and might have a small but clinically relevant survival advantage for patients with spontaneous superficial intracerebral haemorrhage without intraventricular haemorrhage.FundingUK Medical Research Council