[Asymptomatic carotid stenoses. Course and discussion of their treatment]

Asymptomatic carotid stenoses are common. They are associated with the risk factors for arteriosclerosis and are a specific risk factor for coronary artery disease, with an annual morbidity/mortality (MM) rate of 8-10%. Detection of a carotid stenosis should therefore be followed by a complete risk factor analysis and modification, if appropriate; a thorough cardiological diagnostic investigation is particularly important. Individual risk indicators for stroke (annual MM 1-2%) are a rapid progression of the degree of stenosis, certain morphological patterns and the presence of extra- and intracranial multi-vessel disease. Trials available so far on the treatment of asymptomatic carotid stenosis have not revealed any significant parameters that would justify individual decisions on whether or not surgery is appropriate. There is therefore a danger that many patients will be exposed to a severe risk of stroke, which cannot be justified unless the centres where such interventions are performed have proven MM complication rates of <3%, the life expectancy of the patients treated is not restricted as the result of other illnesses and the patients explicitly request surgery after a thorough explanation of the risks. Conservative treatment strategies provide the best protection for the majority of patients.

[Evidence-based radiology: a new approach to evaluate the clinical practice of radiology]

Over the last several years, the concept and methodology of Evidence-Based Medicine (EBM) have received significant attention in the scientific community. However, compared to therapeutic medical disciplines, EBM-based radiological publications are still underrepresented. This article summarizes the principles of EBM and discusses the possibilities of their application in radiology. The presented topics include the critical appraisal of studies on the basis on EBM principles, the explanation of EBM-relevant statistical outcome parameters (e. g., "likelihood ratio" for diagnostic and "number needed to treat" for interventional procedures), as well as the problems facing evidence-based radiology. Evidence-based evaluation of radiological procedures does not only address aspects of cost-effectiveness, but is also particularly helpful in identifying patient-specific usefulness. Therefore it should become an integral part of radiologist training.

Clinical trials design and treatment tailoring: General principles applied to breast cancer research

Nowadays tailored therapy tends to replace standard cancer treatment approaches. Tailoring treatment is possible thanks to clinical trials results that identified subgroups of patients benefiting most from some treatments. Treatment can be tailored on the basis of specific clinical characteristics of the population or on the basis of predictive or prognostic markers. Finally treatment can be tailored for specific molecular targets. This evolution in cancer treatment has triggered the development of innovative trial designs to validate these new hypotheses. The real challenge of the next coming years resides in recruiting large number of patients from specific subgroups to validate tailored therapies.

Fortschritte in der Diagnose und Therapie von Erkrankungen der Augenoberfläche: Trockenes Auge und okuläre Allergien

The 77th meeting of the Association for Research in Vision and Ophthalmology (ARVO) presented the latest developments in clinical research and practice across a range of ophthalmic disciplines. Of particular interest was the current status of research in dry eye and ocular allergy. With these conditions being very common to ophthalmologists, and the fact that they are difficult to differentiate due to the number of overlapping symptoms, there remains a need for more rapid and accurate methods for their diagnosis. Therefore, a number of new tools were presented that have the potential for use in clinical trials and practice to improve the diagnosis and assessment of dry eye and ocular allergy. Some of these tools have been developed based on a greater understanding of the pathophysiology of dry eye and ocular allergy, and the various molecular pathways involved. Indeed, a greater understanding of the molecular mechanisms involved in the pathogenesis of dry eye and ocular allergy has identified potential targets for the treatment of these conditions. Continuing research into new agents can provide ophthalmologists with a number of options that will ultimately benefit the patient.

Present Understanding of Shock Polarity for Internal Defibrillation: The Obvious and Non-Obvious Clinical Implications

BACKGROUND

Uncertainty about the best electrode configuration has combined with the programming flexibility in modern implantable cardioverter-defibrillators (ICDs) to result in routine polarity reversal during an implant to deal with a high defibrillation threshold (DFT). We feel that this practice is not always supported by the clinical data and the present scientific understanding of defibrillation.

METHOD

A meta-analysis of the clinical studies on ICD shock polarity was performed. Subgroup analyses were also performed to test the impact of high DFTs, various tilts, and the use of the hot can electrode. A review of the basic research surrounding the effects of polarity in defibrillation is also presented.

RESULTS

A total of 224 patients were studied. The use of an anodal right ventricular (RV) coil lowers the mean DFT by 14.8% (P = 0.00001). It provides thresholds equal to or lower than cathodal defibrillation in 83% of patients. The fraction of patients with lower anodal DFTs was 94/224 versus 38/224 for cathodal polarity. This phenomenon may be explained by virtual electrode effects. In particular, anodal electrodes tend to produce collapsing wavefronts while cathodal electrodes tend to produce expanding proarrhythmic wavefronts.

CONCLUSION

In an ICD implant, the RV coil should be the anode. Furthermore, DFT testing beginning with cathodal defibrillation is most likely unnecessary and needlessly extends the procedure's duration and increases the risks for the patient.

Total disc replacement in the lumbar spine: a systematic review of the literature

The current evidence for total disc replacement was assessed by performing a systematic review of the published literature. This search identified two randomised controlled trials (RCTs), two previous systematic reviews, seven prospective cohort studies, eleven retrospective cohort studies and eight case series. The RCTs involved the use of the Charité artificial disc and the Pro-Disc II total disc replacement. All papers analysed were classified according to their level of evidence as defined by the Centre for Evidence Based Medicine, Oxford, UK (www.cebm). For degenerative disc disease at L4/5 or L5/S1, both the clinical outcome and the incidence of major neurological complications following insertion of the Charité artificial disc were found to be equivalent to those observed following a single level anterior lumbar interbody fusion 2 years following surgery. However, only 57% of patients undergoing total disc replacement and 46% of patients undergoing arthrodesis met the four criteria listed for success. The range of flexion/extension was restored and maintained with the Charité artificial disc. The role for two or three level disc replacement in the treatment of degenerative disc disease remains unproven. To date, no study has shown total disc replacement to be superior to spinal fusion in terms of clinical outcome. The long-term benefits of total disc replacement in preventing adjacent level disc degeneration have yet to be realised. Complications of total disc replacement may not be known for many years. There are numerous types of disc prostheses and designs under study or in development. Well designed prospective RCTs are needed before approval and widespread application of this technology.

Subatmospheric pressure wound therapy and the vacuum-assisted closure device: basic science and current clinical successes

This article reviews the development, current theories behind the mechanism of action and clinical use of subatmospheric pressure wound therapy with the vacuum-assisted closure device. An evolving list of indications for subatmospheric pressure therapy is discussed including its use in chronic wounds, traumatic wounds and orthopedic salvage, infected sternal wounds, management of the open abdomen, enterocutaneous fistulae, burn wounds, skin grafts and dermal substitutes, as well as systemic disease processes, such as myoglobinuria. The vacuum-assisted closure device Instill system is also reviewed, in which subatmospheric pressure therapy has been combined with the instillation of therapeutic solutions for the treatment of difficult infected wounds.

Halving effort in acute stroke trials

The expense and substantial effort required to conduct multicenter acute stroke trials are potentially limiting factors for progress in this field. To facilitate future work, we need to expand on collaborative approaches to learn from existing trial data sets, for example, using the Virtual International Stroke Trials Archive. Using these networks, we can identify ways of reducing future effort in trials. The interaction between two or more selection criteria can be considered and can allow trials to concentrate on the most informative patients. This has the potential to shorten the recruitment period and increase power simultaneously. Through enhanced training and certification of investigators in assessing outcomes, the main outcome measures may be assessed more accurately. This also should enhance study power. The choice of outcome scale and its method of analysis can have a profound effect on trial power and likely success. The Rankin scale may have advantages over the Barthel index. By combining these various approaches, acute stroke trials can be much more efficient.

D2 lymphadenectomy for gastric cancer in Tata Memorial Hospital: Indian data can now be incorporated in future international trials

BACKGROUND

While mortality rates after radical gastrectomy have decreased, there is considerable morbidity after D2 lymphadenectomy. In this study, we assessed the perioperative results of D2 gastrectomy for gastric cancer.

MATERIALS

Data of 159 patients who underwent D2 gastrectomy for gastric adenocarcinoma at Tata Memorial Hospital was analyzed for interim analysis. The extent of resection, blood loss, transfusions, duration of hospitalization, number of lymph nodes dissected, complications, morbidity and mortality were analyzed.

RESULTS

130 and 29 patients underwent distal and total gastrectomy, respectively (2002-2005) by single specialized surgical unit. Median age was 55 years (range 21-78) and blood loss was 450 ml (range 100-2,200 ml). The median duration of hospitalization was 13 days (range 7-52 days). The median number of dissected lymph nodes was 15 (range 2-46). Minor and major morbidity rate was 4.4 and 4.4% respectively. Mortality rate was 1.25%.

CONCLUSION

Morbidity and mortality following D2 lymphadenectomy is low in this first prospective study from India. With Japan and Western countries having polarized views on D2 lymphadenectomy, future international multicenter trials could also incorporate data such as ours from areas of high incidence of gastric cancer since perioperative outcomes would no longer cloud their results and might provide a better global perspective on D2 lymphadenectomy.

The future of neonatal therapeutic trials

Neonatology has undoubtedly benefited from clinical trials. Nevertheless, more treatments based on inadequate experimental evidence are given than those that are supported by a validated evidence base. Clinicians seeking the basis for their current and future clinical practice are faced with challenges in the shadow of recent UK legislation and government recommendations. All patients must be protected from inappropriate research, but the benefits of regulations must be appropriately balanced with those of properly conducted clinical trials. It is ethically difficult both to persist with treatments of unproven benefit and unknown harm and to deny infants potentially valuable therapies. It is important that trials are conducted within the new legislative framework, but their future may rest with innovative solutions and the determination of all involved in the process.