Ionizing radiation absorption of vascular surgeons during endovascular procedures

ObjectiveEndovascular procedures have become an integral part of a vascular surgeon’s practice. The exposure of surgeons to ionizing radiation and other safety issues have not been well studied. We investigated the radiation exposure of a team of vascular surgeons in an active endovascular unit and compared yearly dosages absorbed by various body parts among different surgeons. Patients’ radiation exposure was also assessed.MethodsThe radiation absorption of a team of vascular surgeons was prospectively monitored in a 12-month period. During each endovascular procedure, the effective body, eye, and hand radiation doses of all participating surgeons were measured by mini-thermoluminescent dosimeters (TLD) attached at the chest level under a lead apron, at the forehead at eye level, and at the hand. The type of procedure, fluoroscopy machine, fluoroscopy time, and personal and operating theatre radiation protection devices used in each procedure were also recorded. One TLD was attached to the patient’s body near the operative site to measure the patient’s dose. The yearly effective body, eye, and hand dose were compared with the safety limits of radiation for occupational exposure recommended by the International Commission on Radiation Protection (ICRP). The radiation absorption of various body parts per minute of fluoroscopy was compared among different surgeons.ResultsA total of 149 consecutive endovascular procedures were performed, including 30 endovascular aortic repairs (EVAR), 58 arteriograms with and without embolization (AGM), and 61 percutaneous transluminal angioplasty and stent (PTA/S) procedures. The cumulative fluoroscopy time was 1132 minutes. The median yearly effective body, eye, and hand dose for the surgeons were 0.20 mSv (range, 0.13 to 0.27 mSv), 0.19 mSv (range, 0.10 to 0.33 mSv) and 0.99 mSv (0.29 to 1.84 mSv) respectively, which were well below the safety limits of the ICRP. The mean body, eye, and hand dose of the chief surgeon per procedure were highest for EVAR. A significant discrepancy was observed for the average hand dose per minute of fluoroscopy among different surgeons. The mean radiation absorption of patients who underwent EVAR, AGM, and PTA/S was 12.7 mSv, 13.6 mSv, and 3.4 mSv, respectively.ConclusionWith current radiation protection practice, the radiation absorbed by vascular surgeons with a high endovascular workload did not exceed the safety limits recommended by ICRP. Variations in practice, however, can result in significant discrepancy of radiation absorption between surgeons

Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases

Central corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. In addition to adding support for known connective tissue-related pathways, pathway analyses uncover previously unreported gene sets. Remarkably, >20% of the CCT-loci are near or within Mendelian disorder genes. These included FBN1, ADAMTS2 and TGFB2 which associate with connective tissue disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes), and the LUM-DCN-KERA gene complex involved in myopia, corneal dystrophies and cornea plana. Using index CCT-increasing variants, we find a significant inverse correlation in effect sizes between CCT and keratoconus (r =-0.62, P = 5.30 × 10-5) but not between CCT and primary open-angle glaucoma (r =-0.17, P = 0.2). Our findings provide evidence for shared genetic influences between CCT and keratoconus, and implicate candidate genes acting in collagen and extracellular matrix regulation

Genetic Sharing with Cardiovascular Disease Risk Factors and Diabetes Reveals Novel Bone Mineral Density Loci.

Bone Mineral Density (BMD) is a highly heritable trait, but genome-wide association studies have identified few genetic risk factors. Epidemiological studies suggest associations between BMD and several traits and diseases, but the nature of the suggestive comorbidity is still unknown. We used a novel genetic pleiotropy-informed conditional False Discovery Rate (FDR) method to identify single nucleotide polymorphisms (SNPs) associated with BMD by leveraging cardiovascular disease (CVD) associated disorders and metabolic traits. By conditioning on SNPs associated with the CVD-related phenotypes, type 1 diabetes, type 2 diabetes, systolic blood pressure, diastolic blood pressure, high density lipoprotein, low density lipoprotein, triglycerides and waist hip ratio, we identified 65 novel independent BMD loci (26 with femoral neck BMD and 47 with lumbar spine BMD) at conditional FDR < 0.01. Many of the loci were confirmed in genetic expression studies. Genes validated at the mRNA levels were characteristic for the osteoblast/osteocyte lineage, Wnt signaling pathway and bone metabolism. The results provide new insight into genetic mechanisms of variability in BMD, and a better understanding of the genetic underpinnings of clinical comorbidity

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Multi-trait genome-wide association study identifies new loci associated with optic disc parameters

A new avenue of mining published genome-wide association studies includes the joint analysis of related traits. The power of this approach depends on the genetic correlation of traits, which reflects the number of pleiotropic loci, i.e. genetic loci influencing multiple traits. Here, we applied new meta-analyses of optic nerve head (ONH) related traits implicated in primary open-angle glaucoma (POAG); intraocular pressure and central corneal thickness using Haplotype reference consortium imputations. We performed a multi-trait analysis of ONH parameters cup area, disc area and vertical cup-disc ratio. We uncover new variants; rs11158547 in PPP1R36-PLEKHG3 and rs1028727 near SERPINE3 at genome-wide significance that replicate in independent Asian cohorts imputed to 1000 Genomes. At this point, validation of these variants in POAG cohorts is hampered by the high degree of heterogeneity. Our results show that multi-trait analysis is a valid approach to identify novel pleiotropic variants for ONH

Epidemiological updates of venous thromboembolism in a Chinese population

Background/Objective: Deep vein thrombosis (DVT) was thought to be uncommon in Asians and routine thromboprophylaxis in the form of anticoagulation for surgical patients was considered to be unnecessary. The current study aims to provide a contemporary epidemiology of venous thromboembolism in a population-based scale. Methods: Information from January 1, 2010 to December 31, 2011 was retrieved from a centralized computer public healthcare database serving mainly an ethnic Han Chinese population of 7.1 million. The incidence, demographics, and hospital mortality rates of DVT and pulmonary embolism (PE) were obtained, and analyzed for different surgical categories. Results: The overall annual incidences of DVT, PE alone, and PE with DVT were 30.0 per 100,000 population, 8.7 per 100,000 population, and 3.0 per 100,000 population, respectively. Overall male to female ratio was 1:1.24. Venous thromboembolic disease was more common with increasing age in both sexes. Thirty days' mortality rates associated with DVT, PE alone, and PE with DVT were 9.0%, 17.4%, and 13.3% respectively. Among the patients who received 103,023 major and intermediate surgical procedures in the study period, the mean incidence of postoperative DVT, PE alone, and PE with DVT were only 0.20% (203.5 patients), 0.08% (85.5 patients), and 0.04% (40.5 patients) respectively. Conclusion: Compared with a similar study 10 years ago, there seemed to be a general increase in incidence of DVT and PE. This study showed that postoperative thromboembolic events were not uncommon, with DVT occurring in up to 0.2% of patients and PE in 0.12% of patients in this longitudinal survey

Analysis of flow patterns on branched endografts for aortic arch aneurysms

Objective: Rupture of aneurysm on the aortic arch leads to significant rates of mortality. Traditional surgical repair is traumatic and may be inappropriate for some patients. Deployment of internally directed side branches provides a feasible alternative, but the hemodynamic implications have not been fully investigated and will be addressed in this study. Method: Both patient specific pre- and post-operative conditions are treated here with computational fluid dynamics. Quantitative indicators like volume flow rate, wall shear stress and helicity index are employed. Results: Changes in volume flow are generally mild unless an antegrade branch is utilized. Wall shear stress reveals a fluctuating and complex flow pattern between the brachiocephalic and left subclavian artery after graft implantation. Circumferentially averaged oscillatory shear indices at the left common carotid artery are in the range of (0.18, 0.26). Helical flows are observed both before and after surgical repairs, and are measured by spatially integrated helicity and a ‘helicity flow index’. Before surgical implant of grafts, blood flows frequently display a predominant direction of rotation. This feature is typically diminished after the implantation. Conclusion: In general, aortic blood flow displayed a higher degree of oscillatory and helical features after internal side branches were deployed. Clinically, oscillatory flows may promote blood clot formation. Furthermore, flow separation points near the outer wall of internal side branches induce fluctuations in pressure and force which might threaten the integrity of the stent graft. To achieve the goal of side branch patency, proper stent orientation is thus critical. Keywords: Aortic aneurysms, Endovascular treatment, Internally directed side branches, Computational fluid dynamics (CFD), Helicity flow index (HFI