How to manage the left subclavian artery during endovascular stenting for thoracic aortic dissection? An assessment of the evidence.

BACKGROUND: Despite the publication of recent guidelines for management of the left subclavian artery (LSA) during endovascular stenting procedures of the thoracic aorta, specific management for those presenting with dissection remains unclear. This systematic review attempts to address this issue. METHODS: Systematic assessment of the published data on thoracic aorta dissection was performed identifying 46 studies, which incorporated 1,275 patients. Primary outcomes included the prevalence of left arm ischemia, stroke, spinal cord ischemia, endoleak, stent migration, and mortality. Outcomes were compared between patients with and without LSA coverage and revascularization incorporating factors such as the number of stents used, length of aorta covered, urgency of intervention, and type of dissection (acute or chronic). Statistical pooling techniques, χ(2) tests, and Fisher's exact testing were used for group comparisons. RESULTS: As compared with other outcomes, LSA coverage without revascularization in the presence of aortic dissection is much more likely to be complicated by left arm ischemia (prevalence increased from 0.0% to 4.0% [p = 0.021]), stroke (prevalence increased from 1.4% to 9.0% [p = 0.009]), and endoleak (prevalence increased from 4.0% to 29.3% [p = 0.001]). However, revascularization was not shown to reverse these effects. Longer aortic coverage (≥ 150 mm) was associated with an increased prevalence of spinal cord ischemia (from 1.3% to 12.5% [p = 0.011]) and mortality (from 1.3% to 15.6% [p = 0.003]). CONCLUSION: In patients undergoing endovascular stenting for thoracic aortic dissection, in cases where LSA coverage is necessary, revascularization should be considered before the procedure to avoid complications such as left arm ischemia, stroke, and endoleak, and where feasible, an appropriate preoperative assessment should be carried out.

Development of the Veritas plot and its application in cardiac surgery: an evidence-synthesis graphic tool for the clinician to assess multiple meta-analyses reporting on a common outcome.

BACKGROUND: Meta-analyses may be prone to generating misleading results because of a paucity of experimental studies (especially in surgery); publication bias; and heterogeneity in study design, intervention and the patient population of included studies. When investigating a specific clinical or scientific question on which several relevant meta-analyses may have been published, value judgments must be applied to determine which analysis represents the most robust evidence. These value judgments should be specifically acknowledged. We designed the Veritas plot to explicitly explore important elements of quality and to facilitate decision-making by highlighting specific areas in which meta-analyses are found to be deficient. Furthermore, as a graphic tool, it may be more intuitive than when similar data are presented in a tabular or text format. METHODS: The Veritas plot is an adaption of the radar plot, a graphic tool for the description of multiattribute data. Key elements of meta-analytical quality such as heterogeneity, publication bias and study design are assessed. Existing qualitative methods such as the Assessment of Multiple Systematic Reviews (AMSTAR) tool have been incorporated in addition to important considerations when interpreting surgical meta-analyses such as the year of publication and population characteristics. To demonstrate the potential of the Veritas plot to inform clinical practice, we apply the Veritas plot to the meta-analytical literature comparing the incidence of 30-day stroke in off-pump coronary artery bypass surgery and conventional coronary artery bypass surgery. RESULTS: We demonstrate that a visually-stimulating and practical evidence-synthesis tool can direct the clinician and scientist to a particular meta-analytical study to inform clinical practice. The Veritas plot is also cumulative and allowed us to assess the quality of evidence over time. CONCLUSION: We have presented a practical graphic application for scientists and clinicians to identify and interpret variability in meta-analyses. Although further validation of the Veritas plot is required, it may have the potential to contribute to the implementation of evidence-based practice.

Do antioxidant vitamins have an anti-arrhythmic effect following cardiac surgery? A meta-analysis of randomised controlled trials.

BACKGROUND: Postoperative atrial fibrillation (POAF) affects approximately 30% of patients undergoing elective cardiac surgery. While its pathogenesis is multifactorial, increasing evidence supports a role for oxidative stress in the electrophysiological remodelling associated with AF. Although prophylactic antioxidants appear to be a potentially attractive pharmacotherapy, there is still uncertainty regarding their efficacy. This study aims to provide a quantitative summary of the current evidence surrounding antioxidant vitamins and POAF prevention. METHODS: A systematic literature review identified five randomised controlled trials incorporating 567 patients (n = 284 antioxidant, n = 283 control). These were meta-analysed using random effects modelling. Heterogeneity, subgroup analysis, quality scoring and risk of bias were assessed. Primary endpoints were the incidence of POAF and all-cause arrhythmia. Secondary endpoints were length of stay in the intensive care unit (ITU) and length of hospital stay. RESULTS: Vitamins C and E significantly reduced the incidence of POAF (OR 0.43, 95% CI 0.21 to 0.89) and all-cause arrhythmia (OR 0.54, 95% CI 0.29 to 0.99) compared with controls. A significant reduction in both ITU stay (weighted mean difference (WMD) -0.44, 95% CI -0.70 to -0.17) and hospital stay (WMD -1.11, 95% CI -1.70 to -0.52) was also seen in the antioxidant group, without significant heterogeneity. CONCLUSIONS: The prophylactic use of vitamins C and E may significantly reduce the incidence of POAF and all-cause arrhythmia following cardiac surgery. However, the overall quality of current studies is poor and further research should focus on adequately powered randomised controlled trials that standardise AF reporting, antioxidant protocol and the use of concomitant agents. Cost analysis should be considered to establish the potential economic benefit of antioxidant vitamin prophylaxis in POAF.

How to manage the left subclavian artery during endovascular stenting of the thoracic aorta.

We performed a systematic review of the literature to establish whether revascularisation of the left subclavian territory is necessary when this artery is covered by a stent. We retrieved data from 99 studies incorporating 4906 patients. Incidences of left-arm ischaemia (0.0% vs 9.2%, p=0.002) and stroke (4.7% vs 7.2%, p<0.001) were significantly less following revascularisation, although mortality (10.5% vs 3.4%, p=0.032) and endoleak incidence (25.8% vs 12.6%, p=0.008) were increased. No significant differences in spinal-cord ischaemia were seen. Revascularisation may reduce downstream ischaemic complications but can cause significant risk. Indications must be carefully considered on an individual patient basis.

Does patent foramen ovale closure have an anti-arrhythmic effect? A meta-analysis.

BACKGROUND: Atrial tachyarrhythmias are associated with patent foramen ovale. The objective was to determine the anti-arrhythmic effect of patent foramen ovale closure on pre-existing atrial tachyarrhythmias. METHODS: Medline, EMBASE, Cochrane Library, and Google Scholar databases were searched between 1967 and 2010. The search was expanded using the 'related articles' function and reference lists of key studies. All studies reporting pre- and post-closure incidence (or prevalence) of atrial tachyarrhythmia in the same patient population were included. Random and fixed effect meta-analyses were used to aggregate the data. RESULTS: Six studies were identified including 2570 patients who underwent percutaneous closure. Atrial fibrillation was in fact the only AT reported in all studies. Meta-analysis using a fixed effects model demonstrated a significant reduction in the prevalence of atrial fibrillation with an OR of 0.43 (95% CI 0.26-0.71). When using the random-effects model, OR was 0.44 (95% CI 0.18-1.04) with a statistically significant trend demonstrated (test for overall effect: Z=1.87, p=0.06). CONCLUSION: Closure of a patent foramen ovale may be associated with reduction in the prevalence of atrial fibrillation.

Translation to success of surgical innovation.

Contemporary thoracic and cardiovascular surgery uses extensive equipment and devices to enable its performance. As the specialties develop and new frontiers are crossed, the technology needs to advance in a parallel fashion. Strokes of genius or problem-solving brain-storming may generate great ideas, but the metamorphosis of an idea into a physical functioning tool requires a lot more than just a thinking process. A modern surgical device is the end-point of a sophisticated, complicated and potentially treacherous route, which incorporates new skills and knowledge acquisition. Processes including technology transfer, commercialisation, corporate and product development, intellectual property and regulatory routes all play pivotal roles in this voyage. Many good ideas may fall by the wayside for a multitude of reasons as they may not be marketable or may be badly marketed. In this article, we attempt to illuminate the components required in the process of surgical innovation, which we believe must remain in the remit of the modern-day thoracic and cardiovascular surgeon.

Effect of skeletonization of the internal thoracic artery for coronary revascularization on the incidence of sternal wound infection.

Use of the internal thoracic artery in coronary revascularization confers excellent benefit. We assessed the impact of skeletonization on the incidence of postoperative sternal wound infection in patients undergoing coronary artery bypass grafting. We also investigated whether there is an advantage in using this technique when harvesting both internal thoracic arteries in high-risk groups, such as diabetic patients. Skeletonization was associated with beneficial reduction in the odds ratio of sternal wound infection (odds ratio, 0.41; 95% confidence interval, 0.26 to 0.64). This effect was more evident when analyzing diabetic patients undergoing bilateral internal thoracic artery grafting (odds ratio, 0.19; 95% confidence interval, 0.10 to 0.34).

Atrial septal defect closure is associated with a reduced prevalence of atrial tachyarrhythmia in the short to medium term: a systematic review and meta-analysis.

Atrial tachyarrhythmias are a common complication of atrial septal defects. The objective was to determine the effect of atrial septal defect closure on pre-existing atrial tachyarrhythmias and to investigate if such an effect is present after either surgical or percutaneous closure. Medline, EMBASE, Cochrane Library, and Google Scholar databases were searched between 1967 and 2009. The search was expanded using the 'related articles' function and reference lists of key studies. All studies reporting pre- and post- closure incidence (or prevalence) of atrial tachyarrhythmias in the same patient groups were included. Data were independently extracted by two authors according to a pre-defined protocol. Incongruities were settled by consensus decision. Twenty six studies were identified including 1841 patients who underwent surgical closure and 945 who underwent percutaneous closure. Meta-analysis using a random effects model demonstrated a reduction in the prevalence of atrial tachyarrhythmias following atrial septal defect closure [OR = 0.66 (95% CI 0.57-0.77)]. This effect was demonstrated after both percutaneous [OR = 0.49 (95% CI 0.32-0.76)] and surgical closure [OR = 0.72 (95% CI 0.60-0.87)]. Immediate (<30 days) and mid-term (30 days - 5 years) follow-up also demonstrated a reduction in AT prevalence [ORs of 0.80 (95% CI 0.66-0.97) and 0.47 (95% CI 0.36-0.62) respectively]. Atrial septal defect closure, whether surgical or percutaneous, is associated with a reduction in the post-closure prevalence of pre-existing atrial tachyarrhythmias and atrial fibrillation in the short to medium term.

Statin therapy may influence the incidence of postoperative atrial fibrillation: what is the evidence?

Atrial fibrillation is the most common postoperative arrhythmia in patients who undergo cardiac surgery. We sought to determine whether the administration of statins reduces the incidence of postoperative atrial fibrillation in cardiac surgery patients. We performed a meta-analysis on all studies published between 2004 and 2008 that reported comparisons between statin treatment or nontreatment in these patients. Our primary focus was the incidence of postoperative atrial fibrillation. Random-effects modeling and sensitivity analysis were used to evaluate the consistency of the calculated treatment effect. Ten qualifying studies generated a total of 4,459 patients. The incidence of postoperative atrial fibrillation was 22.6% (622/2,758) in the statin-treated group and 29.8% (507/1,701) in the untreated group. Using the random-effects model, we calculated an odds ratio (OR) of 0.60 (95% confidence interval [CI], 0.48-0.76). When we considered only the 4 randomized studies (919 patients) in order to reduce the effects of heterogeneity, this significant reduction in the incidence of postoperative atrial fibrillation in the statin group was maintained (OR, 0.55; 95% CI, 0.41-0.73) with no heterogeneity (chi2 of heterogeneity, 2.96; P = 0.4). In studies wherein only coronary artery bypass grafting was performed, statin treatment decreased postoperative atrial fibrillation (OR, 0.64; 95% CI, 0.43-0.95). We conclude that statin administration results in a reduction in the incidence of atrial fibrillation in patients who undergo cardiac surgery. Further research into the underlying mechanism can elucidate possible relationships between the dosage and type of statin used.

Surgeons produce innovative ideas which are frequently lost in the labyrinth of patents.

Thoracic and cardiovascular surgery are innovative specialties that regularly recruit the latest technological developments into their armoury of devices and equipment. The introduction of new technology is dependant on patents; an important but single component of intellectual property. Patents enable the attribution of rights to concepts, ideas and inventions and this facilitates ownership, subsequent licensing and overall management of innovation and its outcome. It is not just thoracic and cardiovascular surgery, but the healthcare world in general that experiences ongoing technological evolution; so to remain contemporary, it is important that those in positions of responsibility are familiar with the relevant processes. This requires basic medico-legal knowledge and may be entwined with significant financial responsibility. Penetrating clinical, academic and industrial environments, informed awareness of patents also contributes to important leadership skills, encouraging the incorporation of innovation into the professional milieu. We aim to present through this manuscript an overview of these issues in order to promote awareness of patents within thoracic and cardiovascular surgery using a descriptive and practical approach.

Current status of robotic assisted pelvic surgery and future developments.

AIMS: The aim of this review is to assess the role of robotics in pelvic surgery in terms of outcomes. We have also highlighted the issues related to training and future development of robotic systems. MATERIALS AND METHODS: We searched MEDLINE, EMBASE and the Cochrane Databases from 1980 to 2009 for systematic reviews of randomised controlled trials, prospective observational studies, retrospective studies and case reports assessing robotic surgery. RESULTS: During the last decade, there has been a tremendous rise in the use of robotic surgical systems for all forms of precision operations including pelvic surgery. The short-term results of robotic pelvic surgery in the fields of urology, colorectal surgery and gynaecology have been shown to be comparable to the laparoscopic and open surgery. Robotic surgery offers an opportunity where many of these obstacles encountered during open and laparoscopic surgery can be overcome. CONCLUSIONS: Robotic surgery is a continually advancing technology, which has opened new horizons for performing pelvic surgery with precision and accuracy. Although its use is rapidly expanding in all surgical disciplines, particularly in pelvic surgery, further comparative studies are needed to provide robust guidance about the most appropriate application of this technology within the surgical armamentarium.