Efficient utilization of graphics technology for space animation

Efficient utilization of computer graphics technology has become a major investment in the work of aerospace engineers and mission designers. These new tools are having a significant impact in the development and analysis of complex tasks and procedures which must be prepared prior to actual space flight. Design and implementation of useful methods in applying these tools has evolved into a complex interaction of hardware, software, network, video and various user interfaces. Because few people can understand every aspect of this broad mix of technology, many specialists are required to build, train, maintain and adapt these tools to changing user needs. Researchers have set out to create systems where an engineering designer can easily work to achieve goals with a minimum of technological distraction. This was accomplished with high-performance flight simulation visual systems and supercomputer computational horsepower. Control throughout the creative process is judiciously applied while maintaining generality and ease of use to accommodate a wide variety of engineering needs

Axillary cerebral perfusion for arch surgery in acute type A dissection under moderate hypothermia

Backgound: Aortic arch surgery is still associated with increased mortality and morbidity especially in acute type A aortic dissection. Adequate brain protection is essential and commonly performed by either antegrade selective perfusion of the brachiocephalic arteries or an interval of profound hypothermic circulatory arrest. We present our experience for open aortic arch repair with continuous antegrade brain perfusion by means of direct cannulation of the right axillary artery, under moderate hypothermia in patients with acute type A aortic dissection. Methods: In, 25 consecutive patients (17 men) with a mean age of 62.6 ± 14.8 years, aortic repair extended to the arch, for acute type A aortic dissection, was performed through a midline sternotomy. The right axillary artery was used for arterial systemic and brain perfusion at a rectal temperature of 25-27 °C. Results: Mean duration of CPB and aortic cross-clamping was 241 ± 55 and 155 ± 72 min, respectively. The mean duration of circulatory arrest of the lower body and brain perfusion was 39.7 (range, 24-55 min). All the patients survived the procedure and all but one were discharged from hospital. One patient had left arm paralysis which he recovered the first postoperative month. There were no other transient or permanent neurologic deficits. A CT scan was performed at discharge for routine postoperative evaluation. There were no local neurovascular complications related to the cannulation site except for one local re-exploration for bleeding. Conclusions: The absence of any major permanent neurologic deficit or any visceral damages in our patients suggests that continuous moderate hypothermic cerebral perfusion, with an interval of circulatory arrest of the lower body, is adequate for acute type A aortic dissection surgery, allowing safe open repair of the distal aortic arc

Incidence, risk factors and prognosis of changes in serum creatinine early after aortic abdominal surgery

Objective: To determine the incidence, risk factors, and prognostic implications of serum creatinine changes following major vascular surgery. Design: Observational study. Settings: University hospital. Patients: Cohort of 599 consecutive patients undergoing elective abdominal aortic surgery. Interventions: Review of prospectively collected data from 1993 to 2004. Measurements and results: The receiver-operator characteristic (ROC) curve analysis was used to detect the best threshold for postoperative elevation in serum creatinine (Δ Creat) in relation to major complications. Acut-off value of +0.5 mg/dl was selected to define renal dysfunction (RD0.5 group, n = 91; no RD0.5, n = 508) that was associated with higher mortality (7.7% in RD0.5 group vs 1.4% in no RD0.5 group, P  40 min; OR, 3.8, 95% CI, 1.9-7.2), blood transfusion (> 5 units; OR, 1.9, 95% CI 1.2-6.1), and rhabdomyolysis (OR, 3.6, 95% CI 1.7-7.9). Conclusions: Postoperative RD0.5 (Δ Creat  > 0.5 mg/dl) occurs in 15% of vascular patients and carries abad prognosis. Preoperative renal insufficiency and factors related to the complexity of surgery are the main predictors of renal dysfunctio

Current Status of Endovascular Training for Cardiothoracic Surgery Residents in the United States

Background Endovascular interventions for cardiovascular pathology are becoming increasingly relevant to cardiothoracic surgery. This study assessed the perceived prevalence and efficacy of endovascular skills training and identified differences among training paradigms. Methods Trainee responses to questions in the 2016 In-Service Training Examination survey regarding endovascular training were analyzed based on the four different cardiothoracic surgery training pathways: traditional 2- and 3-year thoracic, integrated 6-year, and combined 4+3 general and thoracic residency programs. Results The duration of endovascular training was substantially different among programs, at a median of 17 weeks for integrated 6-year, 8.5 weeks for 3-year, 6 weeks for 4+3, and 4 weeks for 2-year residency (p < 0.0001). After adjusting for year of training and program type, the duration of endovascular rotations was significantly associated with self-assessed comfort with catheter-based skills (p < 0.0001). Eighty-two percent of residents rotated with trainees from other specialties, and 58% experienced competition for cases. Residents reported greater exposure to transcatheter aortic valve replacement than to thoracic endovascular aortic repair, cardiac catheterization, percutaneous closure of atrial septal defect, and transcatheter mitral valve surgery (p < 0.0001). A significant proportion of responders reported feeling uncomfortable performing key steps of transcatheter aortic valve replacement (52%) or thoracic endovascular aortic repair (49%). Conclusions Considerable heterogeneity exists in endovascular training among cardiothoracic surgery training pathways, with a significant number of residents having minimal to no exposure to these emerging techniques. These findings highlight the need for a standardized curriculum to improve endovascular exposure and training

Feasibility of aspirin and/or vitamin D3 for men with prostate cancer on active surveillance with Prolaris® testing

OBJECTIVES: To test the feasibility of a randomised controlled trial (RCT) of aspirin and/or vitamin D3 in active surveillance (AS) low/favourable intermediate risk prostate cancer (PCa) patients with Prolaris® testing. PATIENTS AND METHODS: Newly-diagnosed low/favourable intermediate risk PCa patients (PSA ≤ 15 ng/ml, International Society of Urological Pathology (ISUP) Grade Group ≤2, maximum biopsy core length <10 mm, clinical stage ≤cT2c) were recruited into a multi-centre randomised, double-blind, placebo-controlled study (ISRCTN91422391, NCT03103152). Participants were randomised to oral low dose (100 mg), standard dose (300 mg) aspirin or placebo and/or vitamin D3 (4000 IU) versus placebo in a 3 × 2 factorial RCT design with biopsy tissue Prolaris® testing. The primary endpoint was trial acceptance/entry rates. Secondary endpoints included feasibility of Prolaris® testing, 12-month disease re-assessment (imaging/biochemical/histological), and 12-month treatment adherence/safety. Disease progression was defined as any of the following (i) 50% increase in baseline PSA, (ii) new Prostate Imaging-Reporting and Data System (PI-RADS) 4/5 lesion(s) on multi-parametric MRI where no previous lesion, (iii) 33% volume increase in lesion size, or radiological upstaging to ≥T3, (iv) ISUP Grade Group upgrade or (v) 50% increase in maximum cancer core length. RESULTS: Of 130 eligible patients, 104 (80%) accepted recruitment from seven sites over 12 months, of which 94 patients represented the per protocol population receiving treatment. Prolaris® testing was performed on 76/94 (81%) diagnostic biopsies. Twelve-month disease progression rate was 43.3%. Assessable 12-month treatment adherence in non-progressing patients to aspirin and vitamin D across all treatment arms was 91%. Two drug-attributable serious adverse events in 1 patient allocated to aspirin were identified. The study was not designed to determine differences between treatment arms. CONCLUSION: Recruitment of AS PCa patients into a multi-centre multi-arm placebo-controlled RCT of minimally-toxic adjunctive oral drug treatments with molecular biomarker profiling is acceptable and safe. A larger phase III study is needed to determine optimal agents, intervention efficacy, and outcome-associated biomarkers

Anticoagulation with edoxaban in patients with long Atrial High-Rate Episodes ≥24 hours

BACKGROUND AND AIMS: Patients with long atrial high-rate episodes (AHRE) ≥ 24 hours and stroke risk factors are often treated with anticoagulation for stroke prevention. Anticoagulation has never been compared to no anticoagulation in these patients.METHODS: This secondary prespecified analysis of NOAH-AFNET 6 examined interactions between AHRE duration at baseline and anticoagulation with edoxaban compared to placebo in patients with AHRE and stroke risk factors. The primary efficacy outcome was a composite of stroke, systemic embolism, or cardiovascular death. The safety outcome was a composite of major bleeding and death. Key secondary outcomes were components of these outcomes and ECG-diagnosed atrial fibrillation.RESULTS: AHRE ≥24 hours were present at baseline in 259/2389 patients enrolled in NOAH-AFNET 6 (11%, 78 ± 7 years old, 28% women, CHA2DS2-VASc score 4). Clinical characteristics were not different from patients with shorter AHRE. During a median follow-up of 1.8 years, the primary outcome occurred in 9/132 patients with AHRE ≥24 hours (4.3%/patient-year, 2 strokes) treated with anticoagulation and in 14/127 patients treated with placebo (6.9%/patient-year, 2 strokes). AHRE duration did not interact with the efficacy (p-interaction = 0.65) or safety (p-interaction = 0.98) of anticoagulation. Analyses including AHRE as a continuous parameter confirmed this. Patients with AHRE ≥24 hours developed more ECG-diagnosed atrial fibrillation (17.0%/patient-year) than patients with shorter AHRE (8.2%/patient-year; p &lt; 0.001).CONCLUSIONS: This hypothesis-generating analysis does not find an interaction between AHRE duration and anticoagulation therapy in patients with device-detected AHRE and stroke risk factors. Further research is needed to identify patients with long AHRE at high stroke risk.</p

Atrial high-rate episodes and stroke prevention.

While the benefit of oral anticoagulants (OACs) for stroke prevention in patients with atrial fibrillation (AF) is well established, it is not known whether oral anticoagulation is indicated in patients with atrial high-rate episodes (AHRE) recorded on a cardiac implantable electronic device, sometimes also called subclinical AF, and lasting for at least 6 min in the absence of clinically diagnosed AF. Clinical evidence has shown that short episodes of rapid atrial tachycarrhythmias are often detected in patients presenting with stroke and transient ischaemic attack. Patients with AHRE have a higher likelihood of suffering from subsequent strokes, but their stroke rate seems lower than in patients with diagnosed AF, and not all AHRE episodes correspond to AF. The prognostic and pathological significance of AHRE is not yet fully understood. Clinical trials of OAC therapy are being conducted to determine whether therapeutic intervention would be beneficial to patients experiencing AHRE in terms of reducing the risk of stroke

Clinical associations and prognostic value of MRI-visible perivascular spaces in patients with ischemic stroke or TIA: a pooled analysis

BACKGROUND AND OBJECTIVES: Visible perivascular spaces are an MRI marker of cerebral small vessel disease and might predict future stroke. However, results from existing studies vary. We aimed to clarify this through a large collaborative multicenter analysis. METHODS: We pooled individual patient data from a consortium of prospective cohort studies. Participants had recent ischemic stroke or transient ischemic attack (TIA), underwent baseline MRI, and were followed up for ischemic stroke and symptomatic intracranial hemorrhage (ICH). Perivascular spaces in the basal ganglia (BGPVS) and perivascular spaces in the centrum semiovale (CSOPVS) were rated locally using a validated visual scale. We investigated clinical and radiologic associations cross-sectionally using multinomial logistic regression and prospective associations with ischemic stroke and ICH using Cox regression. RESULTS: We included 7,778 participants (mean age 70.6 years; 42.7% female) from 16 studies, followed up for a median of 1.44 years. Eighty ICH and 424 ischemic strokes occurred. BGPVS were associated with increasing age, hypertension, previous ischemic stroke, previous ICH, lacunes, cerebral microbleeds, and white matter hyperintensities. CSOPVS showed consistently weaker associations. Prospectively, after adjusting for potential confounders including cerebral microbleeds, increasing BGPVS burden was independently associated with future ischemic stroke (versus 0-10 BGPVS, 11-20 BGPVS: HR 1.19, 95% CI 0.93-1.53; 21+ BGPVS: HR 1.50, 95% CI 1.10-2.06; = 0.040). Higher BGPVS burden was associated with increased ICH risk in univariable analysis, but not in adjusted analyses. CSOPVS were not significantly associated with either outcome. DISCUSSION: In patients with ischemic stroke or TIA, increasing BGPVS burden is associated with more severe cerebral small vessel disease and higher ischemic stroke risk. Neither BGPVS nor CSOPVS were independently associated with future ICH