Timing of Pedestrian Navigation Instructions

During pedestrian navigation in outdoor urban environments we often utilize assistance systems to support decision-making. These systems help wayfinders by providing relevant information withing the context of their surroundings, e.g., landmark-based instructions of the type "turn left at the church". Next to the instruction type and content, also the timing of the instruction must be considered in order to facilitate the wayfinding process. In this work we present our findings concerning the user and environmental factors that have an impact on the timing of instructions. We applied a survival analysis on data collected through an experiment in a realistic virtual environment in order to analyze the expected distance to the decision point until instructions are needed. The presented results can be used by navigation systems for instruction timing based on the characteristics of the current wayfinder and environment

Feasibility and diagnostic reliability of quantitative flow ratio in the assessment of non-culprit lesions in acute coronary syndrome

Several studies have demonstrated the feasibility and safety of hemodynamic assessment of non-culprit coronary arteries in setting of acute coronary syndromes (ACS) using fractional flow reserve (FFR) measurements. Quantitative flow ratio (QFR), recently introduced as angiography-based fast FFR computation, has been validated with good agreement and diagnostic performance with FFR in chronic coronary syndromes. The aim of this study was to assess the feasibility and diagnostic reliability of QFR assessment during primary PCI. A total of 321 patients with ACS and multivessel disease, who underwent primary PCI and were planned for staged PCI of at least one non-culprit lesion were enrolled in the analysis. Within this patient cohort, serial post-hoc QFR analyses of 513 non-culprit vessels were performed. The median time interval between primary and staged PCI was 49 [42-58] days. QFR in non-culprit coronary arteries did not change between acute and staged measurements (0.86 vs 0.87, p = 0.114), with strong correlation (r = 0.94, p ≤ 0.001) and good agreement (mean difference -0.008, 95%CI -0.013-0.003) between measurements. Importantly, QFR as assessed at index procedure had sensitivity of 95.02%, specificity of 93.59% and diagnostic accuracy of 94.15% in prediction of QFR ≤ 0.80 at the time of staged PCI. The present study for the first time confirmed the feasibility and diagnostic accuracy of non-culprit coronary artery QFR during index procedure for ACS. These results support QFR as valuable tool in patients with ACS to detect further hemodynamic relevant lesions with excellent diagnostic performance and therefore to guide further revascularisation therapy

SAXS imaging reveals optimized osseointegration properties of bioengineered oriented 3D-PLGA/aCaP scaffolds in a critical size bone defect model

Healing large bone defects remains challenging in orthopedic surgery and is often associated with poor outcomes and complications. A major issue with bioengineered constructs is achieving a continuous interface between host bone and graft to enhance biological processes and mechanical stability. In this study, we have developed a new bioengineering strategy to produce oriented biocompatible 3D PLGA/aCaP nanocomposites with enhanced osseointegration. Decellularized scaffolds -containing only extracellular matrix- or scaffolds seeded with adipose-derived mesenchymal stromal cells were tested in a mouse model for critical size bone defects. In parallel to micro-CT analysis, SAXS tensor tomography and 2D scanning SAXS were employed to determine the 3D arrangement and nanostructure within the critical-sized bone. Both newly developed scaffold types, seeded with cells or decellularized, showed high osseointegration, higher bone quality, increased alignment of collagen fibers and optimal alignment and size of hydroxyapatite minerals

Prognostic Impact of Pancoronary Quantitative Flow Ratio Assessment in Patients Undergoing Percutaneous Coronary Intervention for Acute Coronary Syndromes

BACKGROUND Quantitative flow ratio (QFR) has been introduced as a novel angiography-based modality for fast hemodynamic assessment of coronary artery lesions and validated against fractional flow reserve. This study sought to define the prognostic role of pancoronary QFR assessment in patients with acute coronary syndrome (ACS) including postinterventional culprit and nonculprit vessels. METHODS In a total of 792 patients with ACS (48.6% ST-segment-elevation ACS and 51.4% non-ST-segment-elevation ACS), QFR analyses of postinterventional culprit (n=792 vessels) and nonculprit vessels (n=1231 vessels) were post hoc performed by investigators blinded to clinical outcomes. The follow-up comprised of major adverse cardiovascular events, including all-cause mortality, nonfatal myocardial infarction, and ischemia-driven coronary revascularization within 2 years after the index ACS event. RESULTS Major adverse cardiovascular events as composite end point occurred in 99 patients (12.5%). QFR with an optimal cutoff value of 0.89 for postinterventional culprit vessels and 0.85 for nonculprit vessels emerged as independent predictor of major adverse cardiovascular events after ACS (nonculprit arteries: adjusted odds ratio, 3.78 [95% CI, 2.21-6.45], P<0.001 and postpercutaneous coronary intervention culprit arteries: adjusted odds ratio, 3.60 [95% CI, 2.09-6.20], P<0.001). CONCLUSIONS The present study for the first time demonstrates the prognostic implications of a pancoronary angiography-based functional lesion assessment in patients with ACS. Hence, QFR offers a novel tool to advance risk stratification and guide therapeutic management after ACS

Gender-Specific Performance of One- Compared to Two-Catheter Concepts in Transradial Coronary Angiography - Insights From the Randomized UDDC-Radial-Trial

OBJECTIVES The present sub-analysis from the randomized UDDC-Radial-Trial sought to compare one-catheter concepts (OCC) with two-catheter concepts (TCC) in different patient subgroups, particularly in those depending on gender and age. BACKGROUND There is an ongoing debate regarding potential performance differences of OCC compared to TCC for transradial coronary angiography in specific patient subgroups. METHODS The randomized UDDC-Radial-Trial enrolled a total of 300 patients planed for coronary angiography in a 2:1 ratio to either OCC by Tiger II (n = 100) and BLK (n = 100) or TCC by Judkins (n = 100) catheters. Predefined patient subgroups stratified for age, gender and patient constitution were analyzed with regard to the primary outcome measure of time required for a complete coronary angiography. RESULTS In male patients time for coronary angiography was significantly shorter in the TCC group compared to the OCC group (510 ± 37 s vs. 615 ± 35 s; p = 0.046). No difference between the catheter concepts was observed in the subset of female patients (525 ± 34 s vs. 583 ± 54 s; p = 0.43). TCC was associated with shorter coronary angiography time in patients aged <71 years compared to OCC (462 ± 23 s vs. 570 ± 38 s; p = 0.018). In patients ≥72 years of age no difference was detected (573 ± 41 s vs. 636 ± 45 s; p = 0.31). Other subgroups showed no relevant differences in angiography time among OCC and TCC. CONCLUSIONS The present subgroup analysis from the UDDC-radial trial demonstrates the use of OCC in transradial diagnostic angiography to be inferior compared to TCC in terms of angiography time in younger and male patients

Multimodality imaging derived energy loss index and outcome after transcatheter aortic valve replacement

AIMS  To assess whether the combination of transthoracic echocardiography (TTE) and multidetector computed tomography (MDCT) data affects the grading of aortic stenosis (AS) severity under consideration of the energy loss index (ELI) in patients undergoing transcatheter aortic valve replacement (TAVR). METHODS AND RESULTS  Multimodality imaging was performed in 197 patients with symptomatic severe AS undergoing TAVR at the University Hospital Zurich, Switzerland. Fusion aortic valve area index (fusion AVAi) assessed by integrating MDCT derived planimetric left ventricular outflow tract area into the continuity equation was significantly larger as compared to conventional AVAi (0.41 ± 0.1 vs. 0.51 ± 0.1 cm2/m2; P 0.6 cm2/m2. ELI was obtained for conventional AVAi and fusion AVAi based on sinotubular junction area determined by TTE (ELILTL 0.47 ± 0.1 cm2/m2; fusion ELILTL 0.60 ± 0.1 cm2/m2) and MDCT (ELIMDCT 0.48 ± 0.1 cm2/m2; fusion ELIMDCT 0.61 ± 0.05 cm2/m2). When ELI was calculated with fusion AVAi the effective orifice area was >0.6 cm2/m2 in 85 patients (43.1%). Survival rate 3 years after TAVR was higher in patients reclassified to moderate AS according to multimodality imaging derived ELI (78.8% vs. 67%; P = 0.01). CONCLUSION  Multimodality imaging derived ELI reclassifies AS severity in 43% undergoing TAVR and predicts mid-term outcome

Performance of One- Compared With Two-Catheter Concepts in Transradial Coronary Angiography (from the Randomized Use of Different Diagnostic Catheters-Radial-Trial)

The Use of Different Diagnostic Catheters-Radial-Trial sought to compare the safety and efficacy of one-catheter concepts (OCC) using Tiger II or BLK catheters with two-catheter concepts (TCC) using standard Judkins catheters for transradial coronary angiography. A total of 300 patients planed for coronary angiography were enrolled into this single-center, single-blinded trial. Patients were randomized in a 2:1 ratio to either OCC by Tiger II (n = 100) and BLK (n = 100) or TCC by Judkins (n = 100) catheters. Primary end point was time required to perform a complete coronary angiography. Coronary angiography duration was 603 ± 29 seconds and 552 ± 26 sec in the OCC and the TCC groups (p = 0.052). Fluoroscopy time was longer in the OCC (408 ± 28 sec) as compared with the TCC group (258 ± 28 sec, p = 0.009) and the amount of contrast volume used significantly higher (98 ± 5 ml vs 67 ± 4 ml, p < 0.001). Crossover rates were increased in the OCC as compared with the TCC group (37% vs 4%, p < 0.001). These effects were observed irrespective of OCC catheter type. In conclusion, this study demonstrates that OCC do not reduce angiography time, but are associated with an increased amount of contrast volume and longer fluoroscopy time as compared with TCC