Mild aortic insufficiency following transcatheter aortic valve replacement: A systematic review and meta-analysis.

BACKGROUND: Post-procedural aortic insufficiency (AI) continues to be prevalent following transcatheter aortic valve replacement (TAVR). While several studies have assessed the outcomes of moderate-severe AI following TAVR, the incidence, predictors, and outcomes of mild AI remain unclear. METHODS: A systematic literature review was performed to identify studies reporting on mild AI following TAVR. The primary outcome was pooled incidence of post-TAVR mild AI. Secondary outcomes included pooled incidence of mild AI at 30 days and long term. The pooled incidence of midterm mortality in patients with post-TAVR mild AI was also evaluated. The random effect generalized linear mixed-effects model with logit-transformed proportions and Hartung-Knapp adjustment was used to calculate pooled incidence rates. Meta-regression was performed to identify predictors of mild AI. RESULTS: The pooled analysis included 19,241 patients undergoing TAVR across 50 studies. The mean age of patients ranged from 73 to 85 years, and female patients ranged from 20.0% to 83.3%. The overall pooled incidence of post-TAVR mild AI was 56.1% (95% confidence interval [CI] 0.31-0.64). The pooled incidence of mild AI at 30 days was 33.7% (95% CI 0.12-0.37). At mean follow-up of 1.15 years, the pooled incidence of mild AI was 37.0% (95% CI 0.16-0.45). The overall pooled incidence of Midterm mortality (mean follow-up 1.22 years) in patients with mild AI was 14.8% (95% CI 0.10-0.25). At meta-regression, none of the explored variables correlated with a difference in mild AI incidence. CONCLUSIONS: In published studies to date, 50% of patients undergoing TAVR develop mild AI postoperatively. In 37% of patients, this persists in long term. Though the incidence of AI is likely improving with newer generation TAVR valves, the prevalence and outcomes of mild AI should be closely monitored as TAVR volume and indications expand to younger patients with long life expectancy. The long-term outcomes of mild AI remain unclear. Further dedicated studies on post-TAVR mild AI are needed.

Coronary Artery Bypass Grafting in Cardiogenic Shock: Decision-Making, Management Options, and Outcomes.

Coronary artery bypass grafting is a highly efficacious mode of myocardial revascularization that reduces mortality from ischemic heart disease. The patient presenting after acute myocardial infarction in cardiogenic shock presents a unique challenge. Early revascularization is proven to reduce mortality, but many questions remain, including the optimal mode and extent of revascularization, the role of mechanical circulatory support, and which patients are candidates for surgical intervention. Unprecedented attention to the outcomes of cardiac surgery means decisions about the management of the acute myocardial infarction in cardiogenic shock patients are influenced by risk aversion. The authors here review this topic to arm the reader with a comprehensive understanding of the literature to better guide surgical decision-making and perioperative management.

The learning curve of robotic coronary arterial bypass surgery: A report from the STS database.

BACKGROUND: There is limited data to inform minimum case requirements for training in robotically assisted coronary artery bypass grafting (RA-CABG). Current recommendations rely on nonclinical endpoints and expert opinion. OBJECTIVES: To determine the minimum number of RA-CABG procedures required to achieve stable clinical outcomes. METHODS: We included isolated RA-CABG in the Society of Thoracic Surgeons (STS) registry performed between 2014 and 2019 by surgeons without prior RA-CABG experience. Outcomes were approach conversion, reoperation, major morbidity or mortality, and procedural success. Case sequence number was used as a continuous variable in logistic regression with restricted cubic splines with fixed effects. Outcomes were compared between operations performed earlier versus later in case sequences using unadjusted and adjusted metrics. RESULTS: There were 1195 cases performed by 114 surgeons. A visual inflection point occurs by a surgeon's 10th procedure for approach conversion, major morbidity or mortality, and overall procedural success after which outcomes stabilize. There was a significant decrease in the rate of approach conversion (7.7% and 2.5%), reoperation (18.9% and 10.8%), and major morbidity or mortality (21.7% and 12.9%), as well as an increase in the rate of procedural success (72.9% and 85.3%) with increasing experience between groups. In a multivariable logistic regression model, case sequences of >10 were an independent predictor of decreased approach conversion (odds ratio [OR]: 0.27; 95% confidence interval [CI]: 0.09-0.84) and increased rate procedural success (OR: 1.96; 95% CI: 1.00-3.84). CONCLUSIONS: The learning curve for RA-CABG is initially steep, but stable clinical outcomes are achieved after the 10th procedure.

COVID-19 and cardiothoracic surgery: Effects on training and workforce utilization in a global pandemic.

BACKGROUND: The COVID-19 pandemic has disrupted all aspects of healthcare, including cardiothoracic surgery (CTS). We sought to determine the pandemic's impact on CTS trainees' educational experiences. METHODS: A survey was developed and distributed to members of the Thoracic Surgery Residents Association and other international CTS trainees. Trainees were asked to evaluate their cumulative experiences and share their overall perceptions of how CTS training had been impacted during the earliest months of the COVID-19 pandemic (i.e., since March 01, 2020). Surveys were distributed and responses were recorded June 25-August 05, 2020. In total, 748 surveys were distributed and 166 responses were received (overall response rate 22.2%). Of these, 126 of 166 responses (75.9%) met inclusion criteria for final analysis. RESULTS: Final responses analyzed included 45 of 126 (35.7%) United States (US) and 81 of 126 (64.3%) international trainees, including 101 of 126 (80.2%) senior and 25 of 126 (19.8%) junior trainees. Most respondents (76/126, 43.2%) lost over 1 week in the hospital due to the pandemic. Juniors (12/25, 48.0%) were more likely than seniors (20/101, 19.8%) to be reassigned to COVID-19-specific units (p < .01). Half of trainees (63/126) reported their case volumes were reduced by over 50%. US trainees (42/45, 93.3%) were more likely than international trainees (58/81, 71.6%) to report reduced operative case volumes (p < .01). Most trainees (104/126, 83%) believed their overall clinical acumen was not adversely impacted by the pandemic. CONCLUSIONS: CTS trainees in the United States and abroad have been significantly impacted by the COVID-19 pandemic, with time lost in the hospital, decreased operative experiences, less time on CTS services, and frequent reassignment to COVID-19-specific care settings.

Novel two-phase sampling designs for studying binary outcomes.

In biomedical cohort studies for assessing the association between an outcome variable and a set of covariates, usually, some covariates can only be measured on a subgroup of study subjects. An important design question is-which subjects to select into the subgroup to increase statistical efficiency. When the outcome is binary, one may adopt a case-control sampling design or a balanced case-control design where cases and controls are further matched on a small number of complete discrete covariates. While the latter achieves success in estimating odds ratio (OR) parameters for the matching covariates, similar two-phase design options have not been explored for the remaining covariates, especially the incompletely collected ones. This is of great importance in studies where the covariates of interest cannot be completely collected. To this end, assuming that an external model is available to relate the outcome and complete covariates, we propose a novel sampling scheme that oversamples cases and controls with worse goodness-of-fit based on the external model and further matches them on complete covariates similarly to the balanced design. We develop a pseudolikelihood method for estimating OR parameters. Through simulation studies and explorations in a real-cohort study, we find that our design generally leads to reduced asymptotic variances of the OR estimates and the reduction for the matching covariates is comparable to that of the balanced design.

Does a Mobile ECLS Program Reduce Mortality for Patients Transported for ECLS Therapy for Severe Acute Respiratory Failure?

OBJECTIVE: To understand if mobile extracorporeal membrane oxygenation reduces patient mortality during and after transport of patients requiring extracorporeal membrane oxygenation for acute respiratory distress syndrome. DESIGN: Retrospective chart review. SETTING: University affiliated tertiary care hospitals. PARTICIPANTS: Seventy-seven patients. INTERVENTIONS: Introduction of a mobile extracorporeal membrane oxygenation (ECMO) program designed to facilitate the implementation of ECMO at outside hospitals in patients too unstable for transport for ECMO. MEASUREMENTS AND MAIN RESULTS: The 28-day in-hospital mortality was significantly lower in the post-mobile group (12/51 [23.5%] v 12/24 [50%], adjusted risk difference: 28.6%, [95% CI 4.7-52.5, p = 0.011]). CONCLUSIONS: These findings suggest that patients with severe acute respiratory failure who require transport to a referral center for extracorporeal life support may benefit from the availability of a mobile extracorporeal life support team.

Contemporary management and outcomes of acute type A aortic dissection: An analysis of the STS adult cardiac surgery database.

PURPOSE: Management of acute type A aortic dissection (AAAD) is challenging and operative strategies are varied. We used the STS Adult Cardiac Surgery Database (STS ACSD) to describe contemporary surgical strategies and outcomes for AAAD. METHODS: Between July 2011 and September 2012, 2982 patients with AAAD underwent operations at 640 centers in North America. RESULTS: In this cohort, median age was 60 years old, 66% were male, and 80% had hypertension. The most common arterial cannulation strategies included femoral (36%), axillary (27%), and direct aortic (19%). The median perfusion and cross-clamp times were 181 and 102 min, respectively. The lowest temperature on bypass showed significant variation. Hypothermic circulatory arrest (HCA) was used in 78% of cases. Among those undergoing HCA, brain protection strategies included antegrade cerebral perfusion (31%), retrograde cerebral perfusion (25%), both (4%), and none (40%). Median HCA plus cerebral perfusion time was 40 min. Major complications included prolonged ventilation (53%), reoperation (19%), renal failure (18%), permanent stroke (11%), and paralysis (3%). Operative mortality was 17%. The median intensive care unit and hospital length of stays were 4.7 and 9.0 days, respectively. Among 640 centers, the median number of cases performed during the study period was three. Resuscitation, unresponsive state, cardiogenic shock, inotrope use, age >70, diabetes, and female sex were found to be independent predictors of mortality. CONCLUSIONS: These data describe contemporary patient characteristics, operative strategies, and outcomes for AAAD in North America. Mortality and morbidity for AAAD remain high.

Veno-Venous Extracorporeal Life Support in Hemodynamically Unstable Patients With ARDS.

When clinicians consider extracorporeal life support (ECLS) for acute respiratory distress syndrome (ARDS) patients with hemodynamic instability, both veno-arterial (VA) and veno-venous (VV) ECLS are therapeutic possibilities. We analyzed 17 patients with ARDS on inotropic or vasopressor support requiring ECLS for refractory hypoxemia. After implementing VV ECLS, pressor requirements (based on norepinephrine equivalents) were significantly lower in all patients (P = .0001 for overall comparison across time points). None of the 17 patients required conversion from VV ECLS to VA ECLS (95% confidence interval 0%-20.0%). In this sample of 17 patients with substantial baseline vasopressor support and hypoxemic respiratory failure, initiation of VV ECLS was associated with reduced pressor requirements. Such a strategy may help avoid complications of VA ECLS in patients with both respiratory and hemodynamic failure.

Towards an Ethical Framework for Publishing Twitter Data in Social Research: Taking into Account Users' Views, Online Context and Algorithmic Estimation.

New and emerging forms of data, including posts harvested from social media sites such as Twitter, have become part of the sociologist's data diet. In particular, some researchers see an advantage in the perceived 'public' nature of Twitter posts, representing them in publications without seeking informed consent. While such practice may not be at odds with Twitter's terms of service, we argue there is a need to interpret these through the lens of social science research methods that imply a more reflexive ethical approach than provided in 'legal' accounts of the permissible use of these data in research publications. To challenge some existing practice in Twitter-based research, this article brings to the fore: (1) views of Twitter users through analysis of online survey data; (2) the effect of context collapse and online disinhibition on the behaviours of users; and (3) the publication of identifiable sensitive classifications derived from algorithms.

A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans.

The ability of certain oral biofilm bacteria to moderate pH through arginine metabolism by the arginine deiminase system (ADS) is a deterrent to the development of dental caries. Here, we characterize a novel Streptococcus strain, designated strain A12, isolated from supragingival dental plaque of a caries-free individual. A12 not only expressed the ADS pathway at high levels under a variety of conditions but also effectively inhibited growth and two intercellular signaling pathways of the dental caries pathogen Streptococcus mutans. A12 produced copious amounts of H2O2 via the pyruvate oxidase enzyme that were sufficient to arrest the growth of S. mutans. A12 also produced a protease similar to challisin (Sgc) of Streptococcus gordonii that was able to block the competence-stimulating peptide (CSP)-ComDE signaling system, which is essential for bacteriocin production by S. mutans. Wild-type A12, but not an sgc mutant derivative, could protect the sensitive indicator strain Streptococcus sanguinis SK150 from killing by the bacteriocins of S. mutans. A12, but not S. gordonii, could also block the XIP (comX-inducing peptide) signaling pathway, which is the proximal regulator of genetic competence in S. mutans, but Sgc was not required for this activity. The complete genome sequence of A12 was determined, and phylogenomic analyses compared A12 to streptococcal reference genomes. A12 was most similar to Streptococcus australis and Streptococcus parasanguinis but sufficiently different that it may represent a new species. A12-like organisms may play crucial roles in the promotion of stable, health-associated oral biofilm communities by moderating plaque pH and interfering with the growth and virulence of caries pathogens.

Predictors and clinical impact of pre-existing and acquired thrombocytopenia following transcatheter aortic valve replacement.

BACKGROUND: Data are limited regarding transcatheter aortic valve replacement (TAVR)-related thrombocytopenia (TP). We sought to thoroughly characterize the presence, clinical impact, and severity of TP associated with TAVR. METHODS AND RESULTS: Data were collected from 90 patients who underwent TAVR using the Edwards SAPIEN valve (59 TF, 29 TA, 2 Tao). Platelet counts were evaluated peri-procedurally and for 8 days following TAVR. Platelet levels were compared and patients were divided into a no TP (No-TP) group 1, acquired (new) TP (NTP) group 2, pre-existing (pre-TAVR) TP (PTP) group 3, and further stratified based on the severity of TP: mild (M) TP (100-149 × 10(3) cell/µL) and moderate-severe (MS) TP (<100 × 10(3) cell/µL). Pre-TAVR point prevalence and post-TAVR incidence of TP were 40% and 79%, respectively (P < 0.001); nadir platelet count in all groups occurred day 4 post-TAVR. Baseline predictors for developing MS TP in groups 2-3 included baseline TP, leaner body mass, smaller pre-procedural aortic valve area, higher peak aortic jet velocity, and worsening baseline renal function. Development of "major" TP (nadir platelet count <100 × 103 cell/µL, ≥50% decrease) predicted a higher risk of major vascular complications (OR 2.78 [95% CI, 1.58-3.82]) and major bleeding (OR 3.18 [95% CI, 1.33-5.42]) in group 3. CONCLUSION: TAVR-related TP is predictable and classification by PTP and TP severity prior to TAVR allows for better risk stratification in predicting in-hospital clinical outcomes. Major TP in the presence of worsening TP is predictable and is associated with worse clinical outcomes. © 2014 Wiley Periodicals, Inc.

YlxM is a newly identified accessory protein that influences the function of signal recognition particle pathway components in Streptococcus mutans.

Streptococcus mutans is a cariogenic oral pathogen whose virulence is determined largely by its membrane composition. The signal recognition particle (SRP) protein-targeting pathway plays a pivotal role in membrane biogenesis. S. mutans SRP pathway mutants demonstrate growth defects, cannot contend with environmental stress, and exhibit multiple changes in membrane composition. This study sought to define a role for ylxM, which in S. mutans and numerous other bacteria resides directly upstream of the ffh gene, encoding a major functional element of the bacterial SRP. YlxM was observed as a produced protein in S. mutans. Its predicted helix-turn-helix motif suggested that it has a role as a transcriptional regulator of components within the SRP pathway; however, no evidence of transcriptional regulation was found. Instead, capture enzyme-linked immunosorbent assay (ELISA), affinity chromatography, and bio-layer interferometry (BLI) demonstrated that S. mutans YlxM interacts with the SRP components Ffh and small cytoplasmic RNA (scRNA) but not with the SRP receptor FtsY. In the absence of FtsY, YlxM increased the GTP hydrolysis activity of Ffh alone and in complex with scRNA. However, in the presence of FtsY, YlxM caused an overall diminution of net GTPase activity. Thus, YlxM appears to modulate GTP hydrolysis, a process necessary for proper recycling of SRP pathway components. The presence of YlxM conferred a significant competitive growth advantage under nonstress and acid stress conditions when wild-type and ylxM mutant strains were cultured together. Our results identify YlxM as a component of the S. mutans SRP and suggest a regulatory function affecting GTPase activity.

Transcatheter aortic valve replacement: a novel abdominal transaortic approach.

Transcatheter aortic valve replacement (TAVR) via the transfemoral (TF), transapical (TA), or even the transaortic (TAO) approach in high-risk or inoperable patients is quickly becoming a safe and effective modality for the treatment of symptomatic severe aortic stenosis (AS). However, in this selected group of patients, those with anatomical or physiologic constraints preventing TF, TA, and conventional TAO TAVR, alternative sites of access must be explored. Here, we report a successful TAVR in an inoperable patient with severe AS using a distal abdominal TAO approach via a synthetic graft-conduit.

Association of neighborhood socioeconomic status with echocardiographic parameters and re-admission following transcatheter aortic valve replacement.

BACKGROUND: Data on predictors of poor hemodynamic presentation and rehospitalizations following transcatheter aortic valve replacement (TAVR) are limited. We evaluate the association between neighborhood socioeconomic status (NSES) on echocardiographic presentation and post-TAVR readmission at a high-volume institution. METHODS: All patients undergoing TAVR at a single institution between 2012 and 2022 were included. Patient addresses, baseline variables including Society of Thoracic Surgeons (STS) preoperative risk of mortality and frailty, and post-procedural outcomes were extracted from electronic health records. Using a validated US Census Bureau Index, the NSES of each patient (1-100) was tabulated, with lower values correlating to increased social deprivation. Patients were separated into four ranked groups based on NSES (rank 1: 1-25, rank 4: 76-100). Multivariable regression was performed to determine variables associated with number of days hospitalized in one-year following index TAVR procedure. RESULTS: A total of 2031 patients were included. The median NSES was 68 (IQR: 53-80). There was a total of 232 (11.4%) readmissions. The median number of days hospitalized in one year following TAVR was 4 (interquartile range [IQR]: 2-7) After adjusting for baseline variables including STS risk score and patient frailty, compared to patients in the lowest ranked socioeconomic group, patients of higher NSES were associated with lower aortic valve gradients at baselines (Exp[ß]=0.997, 95% CI: 0.993-0.999, P=0.049). Additionally, compared to patients in the lowest ranked socioeconomic group, patients of NSES were associated with shorter duration of readmission after risk-factor adjustments (Exp[ß]=0.996, 95% CI: 0.992-0.999, P=0.032). CONCLUSIONS: Patients of lower socioeconomic status are associated with higher aortic valve gradient at baseline and more days hospitalized in the first year after their index TAVR procedure after adjusting for other risk factors. As TAVR volume continues to expand, physicians and health systems must consider this independent factor when determining patient prognosis and readmission policies.

Early and midterm outcomes following surgery for acute type A aortic dissection.

OBJECTIVE: Surgical repair of acute Type A aortic dissection (AADA) is still associated with high in-hospital mortality. We evaluated the impact of perioperative risk factors on early and midterm survival. METHODS: Retrospective (2002-2011) database analysis at a single institution of 132 consecutive AADA patients (88 male, age 59.8 ± 13.6). All but five patients underwent repair with open distal anastomoses and hypothermic circulatory arrest: aortic valve replacement/root replacement (n=44, 33.3%) and valve re-suspension/repair (n=88, 66.7%). Ascending aorta, hemi-arch, and total arch repairs were performed in 11, 113, and eight patients, respectively. Antegrade and retrograde cerebral perfusion were used in all but six patients. RESULTS: Overall in-hospital mortality was 17.4% (n=23). Actuarial survival at one, five, and eight years was 82%, 72%, and 62%, respectively. Perfusion time (cardiopulmonary bypass) (226.5 ± 71.3 vs. 177.5 ± 51.7, p=0.0002), aortic cross-clamp time (min) (132.8 ± 45.7 vs. 109.8 ± 41.2, p=0.01), aortic arch (T2) tear (31% vs. 14%, p=0.03), instability (26% vs. 11%, p=0.02), postoperative stroke (38% vs. 14%, p=0.009), and low cardiac output (50% vs. 15%, p=0.04) all correlated with increased perioperative mortality. A Cox proportional hazard model showed perfusion time (hazard ratio [HR]=1.01), postoperative stroke (HR=2.73), age (HR=1.03), and unstability (HR=1.8) as significant risk factors (p<0.05) affecting the overall survival. CONCLUSION: There is a modern trend towards improving overall perioperative outcomes after surgical repair of AADA; however, early mortality and morbidity remain high even in aortic surgery referral centers.

Neighborhood Socioeconomic Status Independently Predicts Outcomes After Mitral Valve Surgery.

BACKGROUND: Socioeconomic status has increasingly recognized influence on outcomes after cardiac surgery. However, singular metrics fail to fully capture the socioeconomic context within which patients live, which vary greatly between neighborhoods. We sought to explore the impact of neighborhood-level socioeconomic status on patients undergoing mitral valve surgery in the United States. METHODS: Adults undergoing first-time, isolated mitral valve surgery were queried from The Society of Thoracic Surgeons Adult Cardiac Surgery Database between 2012 and 2018. Socioeconomic status was quantified using the Area Deprivation Index, a weighted composite including average housing prices, household incomes, education, and employment levels. The associations between regional deprivation, access to mitral surgery, valve repair rates, and outcomes were evaluated using logistic regression. RESULTS: Among 137,100 patients included, patients with socioeconomic deprivation had fewer elective presentations, more comorbidity burden, and more urgent/emergent surgery. Patients from less disadvantaged areas received operations from higher volume surgeons and had higher repair rates (highest vs lowest quintile: 72% vs 51%, P < .001, more minimally-invasive approach (33% vs 20%, P < .001), lower composite complication rate (42% vs 50%, P < .001), and lower 30-day mortality (1.8% vs 3.9%, P < .001). After hierarchical multivariable adjustment, the Area Deprivation Index significantly predicted 30-day mortality and repair rate (P < .001). CONCLUSIONS: In a risk-adjusted national analysis of mitral surgery, patients from more deprived areas were less likely to undergo mitral repair and more likely to have complications. Further work at targeting neighborhood-level disparity is important to improving mitral surgical outcomes in the United States.

Pot-bellied Vietnamese pig with visceral mast cell tumors and mastocytemia.

An approximately 12-year-old female Vietnamese Pot-Bellied Pig was presented to the Mississippi State College of Veterinary Medicine Food Animal Service for anorexia of 2 days duration. On physical examination, the patient appeared depressed and lethargic with significantly pale mucus membranes, open mouth breathing, and nostril flaring. On abdominal palpation, the abdomen was tense and uncomfortable. A complete blood count (CBC) and chemistry profile were performed. The CBC revealed significant anemia and mild leukocytosis characterized by mild neutrophilia with a left shift. Mast cells were rarely observed. Hematocrit = 8.1% (RI 22-50), RBC = 1.25 × 106 /µL (RI 3.6-7.8), WBC = 19.85 × 103 /µL (RI 5.2-17.9), Neutrophils = 15.08 × 103 /µL (RI 0-11.4), and Bands = 0.993 × 103 /µL (RI 0-0.019). The chemistry profile was unremarkable with a mildly elevated BUN and slightly decreased total protein and albumin (BUN = 39 mg/dL [RI 4.2-15.1], total protein = 6.2 g/dL [RI 6.6-8.9], and albumin = 2.5 g/dL [RI 3.6-5.0]). An abdominal ultrasound revealed numerous hypoechoic nodules diffusely scattered throughout the hepatic parenchyma. An FNA of one of the hepatic nodules was performed. A mild suppurative component and numerous variably granulated mast cells were observed. A presumptive cytologic diagnosis of mast cell tumor was made. Histopathology was performed, confirming the cytologic interpretation.

CSF from a puppy with a cerebral vascular hamartoma.

A 9-week-old puppy with refractory seizures and a dome-shaped head presented to the Mississippi State College of Veterinary Medicine Specialty Center for suspected hydrocephalus. Computerized tomography (CT) findings included transtentorial herniation and an intra-axial mass with dystrophic mineralization. Cerebrospinal fluid analysis revealed an increased nucleated cell count of 1100/µl (RI < 5/µl), erythrocyte count of 2.2 × 106 /µl, and markedly increased microprotein of 1939 mg/dl (RI < 30 mg/dl). On cytologic examination of the CSF, numerous erythrophagocytic, and hemosiderin-laden macrophages were observed, which indicated chronic active hemorrhage. Many neutrophils, macrophages, and lymphocytes that contained numerous intracytoplasmic, pleomorphic, bright yellow crystals were observed. Considering the ongoing hemorrhage, the crystals were presumed to be hematoidin. A biopsy with histopathology was performed on the intra-axial mass, and the results were consistent with a vascular hamartoma. We speculate that the formation of these crystals was related to the ongoing hemorrhage associated with the vascular hamartoma. Identification of these crystals may be useful to aid in the identification of chronic hemorrhage associated with vascular malformations or lesions within the central nervous system.

Disrupting drive-by download networks on Twitter.

This paper tests disruption strategies in Twitter networks containing malicious URLs used in drive-by download attacks. Cybercriminals use popular events that attract a large number of Twitter users to infect and propagate malware by using trending hashtags and creating misleading tweets to lure users to malicious webpages. Due to Twitter's 280 character restriction and automatic shortening of URLs, it is particularly susceptible to the propagation of malware involved in drive-by download attacks. Considering the number of online users and the network formed by retweeting a tweet, a cybercriminal can infect millions of users in a short period. Policymakers and researchers have struggled to develop an efficient network disruption strategy to stop malware propagation effectively. We define an efficient strategy as one that considers network topology and dependency on network resilience, where resilience is the ability of the network to continue to disseminate information even when users are removed from it. One of the challenges faced while curbing malware propagation on online social platforms is understanding the cybercriminal network spreading the malware. Combining computational modelling and social network analysis, we identify the most effective strategy for disrupting networks of malicious URLs. Our results emphasise the importance of specific network disruption parameters such as network and emotion features, which have proved to be more effective in disrupting malicious networks compared to random strategies. In conclusion, disruption strategies force cybercriminal networks to become more vulnerable by strategically removing malicious users, which causes successful network disruption to become a long-term effort.