Zirconia Implants Produced by Additive Manufacturing - A Scoping Review

INTRODUCTION

Additive manufacturing is a tool with potential use in medicine and dentistry. The manufacture of metals and composites is already advanced, however, concerns about titanium hypersensitivity, tissue staining, and corrosion caused by gradual material degradation encourage research into more biocompatible alternatives.

OBJECTIVE

This systematic scoping review aimed to gather studies that evaluated zirconia implants produced by additive manufacturing to describe the current stage of the printing technique and the final product.

METHODS

Searches in Embase, PubMed, SCOPUS, Web of Science, and Google Scholar databases were enriched with manual searches between February and March 2021 and updated in June 2022 using keywords: zirconium implants, zirconium oxide, additive manufacturing, rapid prototyping, 3D printing, selective laser melting, and electron beam melting. The criteria included studies that evaluated or described zirconia implants obtained by 3D printing, with a direct relationship to dentistry or orthopedics.

RESULTS

The database search resulted in 671 articles. Eight articles were selected for full reading and remained in this systematic review.

CONCLUSION

The printing technique for zirconia implants is promising. However, further studies are required before implants produced by the printing technique can be tested clinically. The literature with results regarding the impression product is still limited.

Denture Adhesives Associated with Silver Vanadate: Antimicrobial Approach Against Multi- Species Biofilms on Acrylic Resin Surfaces

Alternatives have been sought to add an antimicrobial property to denture adhesives. This study evaluated the antimicrobial potential of adhesives associated with nanostructured silver vanadate decorated with silver nanoparticles (β-AgVO3). Specimens in acrylic resin were treated with the adhesives associated with β-AgVO3 (1%, 2.5%, 5% and 10%). As control, specimens treated only with Ultra Corega Cream (UCC) or Ultra Corega Powder (UCP) adhesive were used. Multispecies biofilm of Candida albicans, Candida glabrata, Streptococcus mutans and Staphylococcus aureus was evaluated by counting colony forming units per milliliter (CFU/mL), colorimetric assay and fluorescence microscopy. The data were analyzed using the two-way analysis of variance (ANOVA) and Bonferroni multiple comparisons test (α=0.05). For both adhesives, a small amount of β-AgVO3 (1%) completely inhibited S. mutans (P⟨0.05). For the other microorganisms, there was a reduction in metabolic activity and complete inhibition in the groups with intermediate or greater amounts of nanomaterial (P⟨0.05), except for C. albicans, which was reduced (P⟨0.05) but not completely inhibited in UCP. Microscopy that showed less biofilm in the groups with β-AgVO3 and in the UCC than UCP. Denture adhesives in powder and cream form with β-AgVO3 showed potential antimicrobial activity against multispecies biofilm. Powder adhesive showed higher biofilm formation.

Factors that Affect the Shear Bond Strength of Pit and Fissure Sealants to Tooth Structure: A Systematic Review

INTRODUCTION

Pit and fissure sealants are effective in preventing caries disease, however, they may present flaws that damage the physical barrier leading to treatment failure.

OBJECTIVE

To answer the question ''Do pit and fissure sealants present good adhering to the dental structure when analyzed by their resistance to shear/microshear?".

METHODS

This systematic review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) and was recorded in Open Science Framework. Embase, PubMed, SCOPUS, and Web of Science databases were used for the search strategy. The articles were selected according to the eligibility criteria. The risk of bias was performed with the adaptation of the quasi-experimental studies tool by Joanna Briggs Institute (JBI).

RESULTS

1245 studies were found in the databases when applying the search strategy, after removal of duplicates 881 were evaluated and 44 were selected. After applying the JBI tool, 30 studies presented low risk and 15 moderate risk of bias. Meta-analysis was not possible to performed due to the heterogeneity of the studies.

CONCLUSION

The adhesion is dependent on the application protocol, and among the protocols evaluated, conditioning with 37% phosphoric acid for 60 seconds and contamination of the substrate, as these can affect sealant adhesion.

Patient reported outcomes for phosphomannomutase 2 congenital disorder of glycosylation (PMM2-CDG): listening to what matters for the patients and health professionals

Background

Congenital disorders of glycosylation (CDG) are a growing group of rare genetic disorders. The most common CDG is phosphomannomutase 2 (PMM2)-CDG which often has a severe clinical presentation and life-limiting consequences. There are no approved therapies for this condition. Also, there are no validated disease-specific quality of life (QoL) scales to assess the heterogeneous clinical burden of PMM2-CDG which presents a challenge for the assessment of the disease severity and the impact of a certain treatment on the course of the disease.

Aim and methods

This study aimed to identify the most impactful clinical signs and symptoms of PMM2-CDG, and specific patient and observer reported outcome measures (PROMs and ObsROMs, respectively) that can adequately measure such impact on patients’ QoL. The most burdensome signs and symptoms were identified through input from the CDG community using a survey targeting PMM2-CDG families and experts, followed by family interviews to understand the real burden of these symptoms in daily life. The list of signs and symptoms was then verified and refined by patient representatives and medical experts in the field. Finally, a literature search for PROMs and ObsROMs used in other rare or common diseases with similar signs and symptoms to those of PMM2-CDG was performed.

Results

Twenty-four signs/symptoms were identified as the most impactful throughout PMM2-CDG patients’ lifetime. We found 239 articles that included tools to measure those community-selected PMM2-CDG symptoms. Among them, we identified 80 QoL scales that address those signs and symptoms and, subsequently, their psychometric quality was analysed. These scales could be applied directly to the PMM2-CDG population or adapted to create the first PMM2-CDG-specific QoL questionnaire.

Conclusion

Identifying the impactful clinical manifestations of PMM2-CDG, along with the collection of PROMs/ObsROMs assessing QoL using a creative and community-centric methodology are the first step towards the development of a new, tailored, and specific PMM2-CDG QoL questionnaire. These findings can be used to fill a gap in PMM2-CDG clinical development. Importantly, this methodology is transferable to other CDG and rare diseases with multiple signs and symptoms.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02551-y.

Comparative effectiveness of the new calpain inhibitor NPO-2270 versus enalapril in pressure overload-induced heart failure

Background

Studies performed in multiple preclinical models support the contribution of the Ca2+-dependent cysteine proteases calpains to ventricular remodelling and heart failure (HF). However, pharmacological calpain inhibition has not yet been tested in patients with HF mainly due to the limitations of available inhibitors.

Purpose

To determine the effect of NPO-2270 (NPO), a new ketoamide derivative calpain inhibitor, in a mouse model of pressure-overload and compare its effectiveness with that of enalapril.

Methods

C57BL6 mice were subjected to transverse aortic constriction (TAC) for 4 weeks. Mice were randomised to receive orally administered NPO or enalapril at the dose of 10 mg/kg/day once a day, or vehicle, starting at day 7 after TAC surgery. The combination of both drugs and the effect of NPO starting 1 day after surgery were tested in additional TAC mice. Echocardiographic data, markers of hypertrophy, fibrosis, calpain activity and cleavage of calpain substrates were measured at different time points.

Results

TAC increased calpain-1 and -2 expression and activity. Administration of NPO and enalapril prevented the progression of hypertrophy and interstitial fibrosis induced by TAC with no statistically significant differences between the two treatments. However, ongoing ventricular dysfunction was less severe in the NPO group than in the enalapril group (27% of LVEF reduction in control group, 6% in NPO group and 16% in the enalapril group after TAC, P=0.024 between NPO and enalapril groups). The combined treatment or the administration of NPO from the first day after TAC surgery was not superior to NPO alone starting 7 days after TAC. These differences in LVEF correlated with better preservation of cadherin-based cell adhesion complex in mice treated with NPO-2270. No adverse effects associated with long-term NPO administration were observed in a sham group.

Conclusions

The new calpain inhibitor NPO-2270 prevents the development of hypertrophy and fibrosis with similar efficacy than enalapril but prevents cardiac dysfunction more effectively in a preclinical model of pressure overload when given orally at equivalent doses.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III of the Spanish Ministry of Health

Infarction of the papillary muscle is an independent predictor of heart failure, ventricular tachycardia, and consequent mortality

Background

Previous studies have assessed the effect of papillary muscle infarction (papMI) as seen with Late Gadolinium Enhancement (LGE) Cardiac Magnetic Resonance imaging (CMR) after ST-segment elevation myocardial infarction (STEMI) on patient prognosis. As these studies delivered inconclusive results due to limited sample size and follow-up, we set out to assess whether STEMI patients with papMI are at an increased risk of cardiovascular mortality, heart failure, and arrhythmic events.

Methods

This is a 3-center observational study in n=1,055 consecutive STEMI patients who underwent CMR at a median of 6 (4–9) days, with a mean follow-up of 6.0 years (IQR 3.1–9.1 years). Any presence of papMI, be it supero-lateral, infero-medial, or double, was evaluated visually on the LGE images and checked on the matched cine images. The primary outcomes are time to cardiovascular mortality, heart-failure events defined as heart failure death and hospital admission for heart failure, and arrhythmic events, defined as arrhythmic death and ventricular tachycardia (VT).

Results

PapMI was diagnosed in 351 patients (33%). PapMI is an independent predictor of cardiovascular mortality after correction for clinically relevant parameters such as infarct size and left ventricular ejection fraction (Multivariate Cox Regression Hazard Ratio (HR)=2.46, 95% confidence interval (CI) 1.23–4.92). Secondly, papMI independently predicts the combined endpoints of heart failure death/heart failure (HR=1.72, 95% CI 1.12–2.63) and arrhythmic death/ VT (HR=4.52, 95% CI 2.18–9.36).

Conclusions

PapMI predicts cardiovascular mortality, arrhythmic death and heart failure. PapMI should be taken into account, especially when conducting new prognosis studies after STEMI and as a stratification factor in studies for secondary prevention of VT and arrhythmic death.

Funding Acknowledgement

Type of funding sources: Other.

Sex-based differences on adverse left ventricular remodeling and clinical outcomes after an ST-segment elevation myocardial infarction in the PCI era

Background

There is conflicting evidence regarding sex-based differences in myocardial salvage and clinical outcome in patients after an ST-segment elevation myocardial infarction (STEMI) in the contemporary era of primary percutaneous coronary intervention (PCI) and optimal medical treatment.

Adverse left ventricular remodelling (LVR) after a STEMI worsens outcomes, however, the influence of sex is not yet clear.

Aim/Purpose

To analyze whether there are sex differences in clinical outcomes and adverse LVR in patients after a STEMI.

Methods

Patients with STEMI who underwent primary PCI were included and a cardiac magnetic resonance (CMR) was performed during hospitalization (6.2±2.6 days) and after 6 months (6.1±1.8 months). LVR, myocardial salvage (MS), infarct size (IS), microvascular obstruction (MVO), and area at risk (AAR) were quantified. Adverse LVR was defined as a 15% increase in LV end-diastolic volume and a relative fall in LV ejection fraction of 3% at 6 months. The primary outcome was a composite of cardiovascular death, admission for heart failure, or ventricular arrhythmia.

Results

A total of 1046 patients were included (mean age: 59.8±9 years; 16.6% women), and a second CMR was completed in 589 patients. Women were older (58.8±8 years vs 65.0±10 years, p<0.0001) and presented more cardiovascular risk factors (Table). The primary outcome occurred in 310 patients during follow-up of 75 months (range: 36–112 months) and was more frequent in women than in men (35.8% vs 22.3%, p<0.001). After adjusting for baseline differences (age, diabetes, hypertension, Killip class, and time to reperfusion), female sex was not an independent predictor of major adverse cardiac events (Fig. 1A & B).

Although adverse LVR was a strong independent predictor for the primary outcome, no interaction was present between sex and LVR (women 6.4% vs men 8%, p=0.46) (Fig 1B), nor did we find significant differences between sex and other CMR derived variables such as MS, IS, MVO and AAR.

Conclusions

After a STEMI, women present worse clinical outcomes than men. However, these differences are related to their clinical characteristics and higher incidence of cardiovascular risk factors, and not to a higher incidence of adverse left ventricular remodeling.

Funding Acknowledgement

Type of funding sources: None.

Predictors of long term tricuspid regurgitation after pulmonary valve replacement: a single center study on the cohort of significant preoperative tricuspid regurgitation

Background

Almost one-third of repaired tetralogy of Fallot (TOF) and pulmonary stenosis (PS) patients referred for pulmonary valve replacement (PVR) have at least moderate tricuspid regurgitation (TR). Predictors of long term TR in this population are not well defined and the role of Tricuspid Annuloplasty (TA) in addition to PVR in this setting is controversial.

Purpose

Patients with preoperative severe TR or moderate TR with dilated tricuspid annulus (>40mm) undergo TA at the time of PVR as per protocol in our instititution. The aim of this observational study was to evaluate the long term results of this approach and to identify predictors of significant TR at the end of follow-up.

Material and methods

We retrospectively reviewed 35 repaired TOF and PS patients who underwent surgical PVR with (n=17, group 1) or without (n=18, group 2) TA in a single tertiary hospital between June-2009 and June-2021. Pre- and postoperative echocardiographic and cardiac magnetic resonance data were assessed for TR severity and right ventricle size and systolic function. Baseline and clinical follow up data were collected. Uni- and multivariable tests were used to analyze predictors of at least moderate TR after PVR.

Results

Mean age at PVR and baseline image parameters were comparable between groups, except for TR grade (p 0.006), tricuspid annulus size (p 0.018) and right ventricle outflow tract diameter (p 0.04) which were greater in group 1. TA did not confer and increased risk of surgical and peroperative complications. Intensive care unit (p 0.94) and total hospital admission days (p 0.59) did not differ among groups. At one year, TR grade significantly improved regardless of TA. At the end of follow-up (5.29±2.9 years), the degree of TR increased in both groups with no differences between groups (p 0.38) (see table 1). In univariable analysis, two independent predictors of at least moderate TR at end of follow-up were identified; mixed TR mechanism (OR 12.5, p 0.006) and severe preoperative TR grade (OR 10.21, p 0.003). Mixed TR mechanism (OR 15.78, p 0.01) and a right ventricle ejection fraction below 45% (OR 1.47, p 0.01) were identified as risk factors of significant TR in multivariable analysis (see Table 2).

Conclusions

TA seems a reasonable approach at the time of PVR in patients with severe TR or moderate TR with dilated annulus. Mixed TR mechanism and a worse right ventricular function have been identified as independent predictors factors of long term significant postoperative TR in our study cohort.

Funding Acknowledgement

Type of funding sources: None.

Prospective international validation of the predisposition, infection, response and organ dysfunction (PIRO) clinical staging system among intensive care and general ward patients

Background

Stratifying patients with sepsis was the basis of the predisposition, infection, response and organ dysfunction (PIRO) concept, an attempt to resolve the heterogeneity in treatment response. The purpose of this study is to perform an independent validation of the PIRO staging system in an international cohort and explore its utility in the identification of patients in whom time to antibiotic treatment is particularly important.

Methods

Prospective international cohort study, conducted over a 6-month period in five Portuguese hospitals and one Australian institution. All consecutive adult patients admitted to selected wards or the intensive care, with infections that met the CDC criteria for lower respiratory tract, urinary, intra-abdominal and bloodstream infections were included.

Results

There were 1638 patients included in the study. Patients who died in hospital presented with a higher PIRO score (10 ± 3 vs 8 ± 4, p < 0.001). The observed mortality was 3%, 15%, 24% and 34% in stage I, II, III and IV, respectively, which was within the predicted intervals of the original model, except for stage IV patients that presented a lower mortality. The hospital survival rate was 84%. The application of the PIRO staging system to the validation cohort resulted in a positive predictive value of 97% for stage I, 91% for stage II, 85% for stage III and 66% for stage IV. The area under the receiver operating characteristics curve (AUROC) was 0.75 for the all cohort and 0.70 if only patients with bacteremia were considered. Patients in stage III and IV who did not have antibiotic therapy administered within the desired time frame had higher mortality rate than those who have timely administration of antibiotic.

Conclusions

To our knowledge, this is the first external validation of this PIRO staging system and it performed well on different patient wards within the hospital and in different types of hospitals. Future studies could apply the PIRO system to decision-making about specific therapeutic interventions and enrollment in clinical trials based on disease stage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00966-7.

Clinical impact on treatment and prognosis of advanced cardiac imaging with echocardiography in the acute setting of a COVID-19 infection

Background and objectives

Despite myocardial injury being related to excess mortality in acute COVID-19 infection, its impact on imaging findings remains unclear. This study aimed to characterize transthoracic echocardiographic (TTE) findings in patients admitted with COVID-19 infections and its impact on management and prognosis.

Methods

A prospective observational cohort study was performed among 66 COVID-19 patients who were admitted to a tertiary center between March 1 and May 25, 2020 and underwent TTE. High-sensitivity troponin I (hs-cTnI) data, echocardiographic assessment of right and left ventricular (LV) functional parameters, strain, and myocardial work analysis were obtained.

Results

2025 patients were admitted with COVID-19 and in 200 a complete TTE study was performed. Due to poor image quality, only 66 studies were included in the final analysis. The median age was 62 years (IQR, 55–70) and 59.1% of patients were males. The most common comorbidity was hypertension (47%), followed by smoking history (30.3%), atrial fibrillation (9.1%), and chronic obstructive pulmonary disease (7.9%). More than half of the patients (39, 59%) were admitted to the ICU, and half of them (33, 50%) required invasive mechanical ventilation. TTE was mainly indicated because of concerns for systemic conditions (50%) and evaluation of hemodynamic assessment (30%). Thirty-six patients (54.5%) had an abnormal TTE result and 57% had elevated hs-cTnI levels. The most common cardiac abnormality was LV diastolic dysfunction in 33% of the patients, followed by right ventricular dysfunction (12%) and LV dysfunction (6%) (Figure 1). LV GLS was reduced in 48.5% of the cases. Myocardial work performance indices were all reduced in patients with an abnormal TTE (GWI 30%, GCW 30%, GWW 40%, and GWE 40%), although differences were not significant (P&gt;0.2 for all parameters). Patients with an abnormal TTE were older and presented a higher cardiovascular risk profile. There were no significant differences in the levels of D-dimer, NTproBNP, and hs-cTnI between patients with and without diastolic dysfunction, RV, or LV dysfunction (P&gt;0.3 for all parameters). Using Spearman rank correlation, there was an inverse relationship between hs-cTnI and LV strain and myocardial work analysis. TTE results impacted clinical management in 60 patients, mainly de-escalation of medical treatment (Figure 2). Abnormal TTE results did not impact in-hospital outcomes.

Conclusions

Severe echocardiographic abnormalities are uncommon in hospitalized patients with COVID-19 infections, presenting mostly with subclinical myocardial changes, such as diastolic dysfunction, reduced LV GLS, and myocardial work indices, both associated with high-sensitivity troponin I elevation. An echocardiographic study should be limited to rule out long-term ICU complications or to evaluate hemodynamic instability. Although TTE was a valuable tool for guiding management, it had no significant impact on prognosis.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Findings on TTE studies.Figure 2. Changes in management.

Prognostic value of baseline versus 6-month follow infarct size in patients with reperfused STEMI

Background

Acute infarct size is a predictor of clinical outcomes in acute ST segment elevation myocardial infarction (STEMI) patients, although its prognostic value has differed between studies. In acute STEMI, infarct size is often overestimated due to the presence of extensive myocardial oedema, a confounder that is no longer present at a 6-month follow-up study. It was our purpose to assess whether infarct size in the acute phase or at 6-months follow-up provided superior prognostic information in STEMI patients.

Methods

STEMI patients who underwent successful primary percutaneous revascularization were included and a cardiac magnetic resonance (CMR) was performed between 5–7 days after STEMI and at 6 months to study infarct size (as a % of myocardial mass). The primary endpoint was a composite of cardiovascular mortality, hospitalization for heart failure and ventricular arrhythmia.

Results

A total of 796 patients were included (mean age 58.3±11.5 years, 82.4% male, 52.3% anterior infarction). During a mean follow-up of 59 months, 59 patients (7.4%) presented with the primary end-point (cardiovascular death n=7, hospitalization for heart failure n=52, ventricular arrhythmia n=1). ROC curve analysis (figure 1) showed a non-significant difference between baseline and 6-month infarct size for the prediction of the primary endpoint (baseline AUC 0.685 95% CI 0.610–0.760, 6-month AUC 0.713 95% CI 0.643–0.782, p=0.60). Optimal cut-off values for baseline and 6-months follow-up infarct size for prediction of outcomes, respectively 22% and 17.5%, were used for Kaplan-Meier curve analysis (figure 2).

Conclusion

Infarct size estimated during the first week after STEMI and at 6-months follow-up showed similar predictive value and with similar cut-off values. Therefore, the prognostic information provided by infarct size can be obtained during initial STEMI admission and does not require a waiting period for infarct size stabilization.

Funding Acknowledgement

Type of funding sources: None. ROC curve analysisKaplan-Meier analysis

Influence of operator experience on the technical and clinical results of Woven EndoBridge endovascular treatment for intracranial aneurysms

BACKGROUND & PURPOSE

The safety and efficacy of the Woven EndoBridge (WEB) device has been proven in recent multicenter trials. This study investigated whether operator experience influences WEB treatment-related outcomes.

MATERIAL AND METHODS

This was a retrospective analysis of a prospectively collected multicenter database. The data of all patients who underwent WEB treatment for an intracranial aneurysm from March 2014 to June 2020 in two high-volume centers were pooled. Operator experience was indexed by the number of WEB treatments performed previously. The primary endpoint was the overall complication rate. Secondary endpoints were long-term adequate (Raymond-Roy classification of 1-2.) angiographic occlusion, WEB-related complications, number of WEB not deployed, procedure duration, and radiation exposure (air kerma).

RESULTS

Among 237 patients (mean age 59.4 +/- 11.5 years) treated with WEB (median aneurysm diameter, 5.8 mm; interquartile range 4.5-7 mm), WEB-related complications occurred in 28 patients (11.8%) and adequate long-term occlusion was achieved for 154 aneurysms (86%). The median number of WEB treatment performed previously per operator was 20 (IQR, 9-41). The overall complication rate, WEB-related complication rate and aneurysm occlusion rate were not significantly correlated with WEB operator experience. There were also no significant correlations between the WEB operator experience and the number of WEB not deployed, procedure duration or radiation exposure.

CONCLUSION

There was no significant association between the number of WEB treatments previously performed per operator and any technical or clinical results after intracranial aneurysm treatment with WEB. These results imply a relatively short learning curve for this device in high-volume neurovascular centers.

Aortic rotational flow patterns and stiffness by 4D flow CMR in patients with Loeys-Dietz syndrome compared to healthy volunteers and patients with Marfan syndrome

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): La Marató de TV3, Instituto de Salud Carlos III through the project and Spanish Ministry of Science, Innovation and Universities.

BACKGROUND

Loeys-Dietz (LDS) and Marfan (MFS) syndromes are rare genetic connective tissue disorders associated with progressive aortic dilation, however, aortic dissections have been observed at lower aortic root diameters in LDS than in MFS. Recent CMR studies in MFS patients reported increased aortic stiffness (1–3) and altered rotational flow (4), but research on aortic flow dynamics and biomechanics in LDS is lacking.

PURPOSE

The aim of this study was to assess rotational aortic flow and aortic stiffness in LDS compared to healthy volunteers (HV) and MFS patients, using 4Dflow CMR.

METHODS

Twenty-one LDS and 44 MFS patients, without previous aortic dissection or surgery, and 43 HV underwent a non-contrast-enhanced 4D flow CMR. Aortic stiffness was quantified at the AAo and DAo using pulse wave velocity (PWV). In-plane rotational flow (IRF), systolic flow reversal ratio (SFRR) (5) and local aortic diameters were obtained at 20 equidistant planes from the ascending (AAo) to the proximal descending aorta (DAo).

RESULTS

LDS patients had lower IRF at the distal AAo and proximal DAo compared to HV (p = 0.053 and 0.004, respectively), once adjusted for age, stroke volume and local aortic diameter; but no differences were found with respect to MFS (Figure). Although SFRR at the proximal DAo was increased in LDS patients compared to both HV (p = 0.037) and MFS populations (p = 0.015), once adjusted for age and aortic diameter, the difference in magnitude was small (Figure). On the other hand, AAo and DAo PWV revealed stiffer aortas in LDS patients compared to HV but no differences versus MFS patients (Table).

CONCLUSIONS

Patients with Loeys-Dietz syndrome showed decreased in-plane rotational flow and abnormally-high regional aortic stiffness compared to healthy controls, and similar hemodynamics and aortic stiffness with respect to patients with Marfan syndrome.

Probiotic properties of yeasts isolated from Brazilian fermented table olives

AIMS

To investigate the probiotic potential of yeasts isolated from naturally fermented Brazilian table olives.

METHODS AND RESULTS

Eighteen yeast strains were tested in terms of: safety; survival of gastrointestinal and digestion conditions; antimicrobial activity; cellular hydrophobicity; autoaggregation ability and adhesion to epithelial cells; coaggregation and inhibition of pathogenic bacteria adhesion. Six yeasts showed favourable results for all probiotic attributes: Saccharomyces cerevisiae CCMA 1746, Pichia guilliermondii CCMA 1753, Candida orthopsilosis CCMA 1748, Candida tropicalis CCMA 1751, Meyerozyma caribbica CCMA 1758 and Debaryomyces hansenii CCMA 1761. These yeasts demonstrated resistance to 37°C, pH 2·0 and bile salts, and survived in vitro digestion (≥10⁶  CFU per ml). Furthermore, the yeasts exhibited a hydrophobic cell surface (42·5-92·2%), autoaggregation capacity (41·0-91·0%) and adhesion to Caco-2 (62·0-82·8%) and HT-29 (57·6-87·3%) epithelial cell lines. Also, the strains showed antimicrobial activity against Salmonella Enteritidis as well as the ability to coaggregate and reduce the adhesion of this pathogen to intestinal cells.

CONCLUSIONS

Autochthonous yeasts from naturally fermented Brazilian table olives have probiotic properties, with potential for development of new probiotic food products.

SIGNIFICANCE AND IMPACT OF STUDY

These data are important and contribute to the knowledge of new potential probiotic yeasts capable of surviving gastrointestinal tract conditions and inhibiting pathogenic bacteria.

Long term outcomes in left ventricular noncompaction

Funding Acknowledgements

Type of funding sources: None.

Background

Left ventricular noncompaction (LVNC) is a heterogeneous entity with a wide phenotypic expression. Risk factors have not been well established and prognostic stratification remains challenging.

Objectives

Describe long term outcomes of LVNC patients and determine predictors of cardiovascular events. 

Methods

 

Prospective multicentric study of consecutive patients fulfilling imaging diangostic criteria for LVNC (Jenni echo criteria and Petersen CMR criteria). Demographic, ECG, imaging and genetic variables were collected. End points were heart failure (HF), ventricular arrhythmias (VA), systemic embolisms (SE) and all-cause death. Major adverse cardiovascular events (MACE) was the combination of the four previous end points.

Results

585 patients from 12 referral centres were included from 2000 to 2018. Age at diagnosis was 45 ± 20 years, 334 (57%) were male, baseline LVEF was 48 ± 17% and 18% presented late gadolinium enhancement (LGE). During a median follow-up of 5.1 years (IQR 2.3-8.1), 110 (19%) patients presented HF, 87 (15%) VA, 18 (3%) SE and 34 (6%) died. MACE occurred in 223 (38%) patients.

LVEF was independently associated with HF, VA, SE and MACE: HR were 1.08, 1.02, 1.04 and 1.02 respectively (all p &lt; 0.05). LGE was more frequent in patients with reduced LVEF (39 Vs 53%, p &lt; 0.001) and was associated with higher HF and VA risk in patients with LVEF &gt; 35% (HR 2.69 and 2.48 respectively, p &lt; 0.05) (Figure 1). Patients with a normal ECG, LVEF≥50%, no LGE and no family aggregation presented no MACE (0%) at long term follow-up.

Among patients who underwent genetic testing (354, 61%), TTN variants and complex genotype (more than one variant) presented lower LVEF and higher HF risk. ACTC1 variants were associated with VA.

Conclusions

LVNC carries a high long term risk of heart faliure and ventricular arrhythmias. LVEF is the most important predictor and myocardial fibrosis is associated with increased risk in patients without severe systolic dysfunction. Genotype is a modifier of outcomes. These factors might be used to risk stratify LVNC patients.

Abstract Figure. Kaplan Meier survival curves

Aortic root longitudinal strain by speckle-tracking echocardiography predicts progressive aortic root dilation in Marfan syndrome patients

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Science, Innovation and Universities; Instituto de Salud Carlos III

Introduction

In Marfan syndrome (MFS) patients reduced longitudinal strain of the ascending aorta (AAo) as measured by applying feature-tracking on cine cardiac magnetic resonance (CMR) images predicts aortic root dilation and aortic events during the follow-up. Speckle-tracking is well established for cardiac deformation assessment but proximal aorta applications are challenging due to limited wall thickness and substantial cardiac motion. Moreover, echocardiography is widely used in the clinical assessment aortic diseases.

Purpose

We aimed to test a speckle-tracking tool for root longitudinal strain analysis in terms of comparison with CMR-derived AAo longitudinal strain and reproducibility and as predictor of dilation in MFS patients.

Methods

Thirty-five MFS patients diagnosed by original GHENT criteria, with maximum aortic root diameter of 45 mm and free from previous aortic dissection or cardiac/aortic surgery and non-severe aortic regurgitation were consecutive enrolled and followed-up. CMR and echocardiography were performed less than 2 months apart. Baseline and final aortic root diameter were measured on CMR images. To quantify aortic root cyclic elongation by echocardiography, two regions of interests were manually created covering both walls in a parasternal long-axis view and tracked along the cardiac cycle (Figure 1). Longitudinal strain was computed as the average of maximum increase in relative distance of several sub-regions covering both walls. CMR-derived AAo longitudinal strain was available in 29 patients. Intra-observer reproducibility was tested in 15 patients via intraclass correlation coefficient (ICC) for single-rater absolute agreement.

Results

Aortic root longitudinal strain by echocardiography was mildly related to CMR-derived AAo longitudinal strain (R = 0.27) and was larger compared to CMR-derived values (16.2 ± 6.0 vs 11.3 ± 4.3). Reproducibility was high, with ICC of 0.811, R = 0.802, p &lt; 0.001. After a mean follow up of 76 ± 13 months, aortic root diameter grew in 20 patients with a rate of 0.29± 0.24 mm/year. Overall mean growth-rate was 0.87 ± 0.33 mm/year. In multivariable analysis corrected for age and baseline aortic root diameter, baseline longitudinal strain by echocardiography was independently and inversely related to progressive dilation (p = 0.033).

Conclusions

The measurement of aortic root longitudinal strain by speckle-tracking echocardiography is feasible. Aortic root longitudinal strain is an independent predictor of progressive dilation in MFS patients. This may permit the improvement of risk-stratification in aortic diseases in large scale studies.

Abstract Figure 1

Leaflets fusion length in bicuspid aortic valve is related to ascending and aortic root dilation and ascending aorta wall shear stress

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Spanish Ministry of Science, Innovation and Universities, Instituto de Salud Carlos III

Background

Bicuspid aortic valve (BAV) is the most common congenital heart defect, consisting in the fusion of two aortic valve leaflets. Altered flow patterns have been related to aortic wall degeneration in BAV patients and may be responsible for the high prevalence of aortic disease in these patients. A number of studies on excised BAV or using advanced imaging modalities reported a wide variability of fusion extent between leaflet, but no previous study assessed whether leaflet fusion length may be used to stratify BAV patients.

Purpose

We aimed to test whether leaflet fusion extent can be quantified by cardiac magnetic resonance imaging (CMR) and whether it is related to aortic dilation and flow abnormalities in non-dysfunctional BAV.

Methods

One hundred and twenty BAV adults with no previous aortic or aortic valve surgery or significant valvular disease were consecutively enrolled. Patients with two sinuses of Valsalva (true BAV) or fusion of the left and non-coronary cusps, both being rare forms of BAV, were excluded. Twenty-eight healthy volunteers were also included for comparison. A 4D flow CMR sequence was acquired and circumferential wall shear stress and pulse wave velocity were assessed in the ascending aorta. A stack of double-oblique cine images of the aortic valve were used to quantify the length of the fusion between leaflets.

Results

The length of the fusion between leaflets was effectively measured in 112/120 patients (93%). Reproducibility was good (ICC = 0.826). Fusion length varied greatly (range 2.3 – 15.4 mm, 7.8 ± 3.2 mm, tertiles cut-off points were 6 and 9.3 mm). After correction for age, BSA, stroke volume and BAV fusion morphotype, fusion length was independently associated with diameter at the sinus of Valsalva (p = 0.002). Moreover, once corrected for age, stroke volume and ascending aorta pulse wave velocity, fusion length was positively related to ascending aorta diameter (p = 0.028). The comparison of maps of circumferential peak-systolic WSS in healthy volunteers (left) and BAV patients pertaining to the three leaflet fusion length tertiles is shown in Figure 1. Circumferential WSS progressively increase with larger fusion length. This trend was statistically significant (p &lt; 0.05) in the right and outer regions of the proximal and mid ascending aorta.

Conclusions

Bicuspid aortic leaflet fusion length varies considerably and it is independently associated with ascending aorta and aortic root dilation, possibly through flow alterations.

Abstract Figure 1

Regional curvature in thoracic aortic aneurysms of different aetiologies and its relationship with established risk factors

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Science, Innovation and Universities ; Instituto de Salud Carlos III

Introduction

The aorta is a 3D hollow, curvilinear elastic structure whose diseases have life-threatening consequences. Despite much effort has been paid to study aortic diameter, diameter is a poor predictor of events. Conversely, much less is known about aortic curvature, its distribution in the thoracic aorta and the potential impact of risk factors in aneurysms associated with different conditions. Currently, 4D flow magnetic resonance imaging (4D flow CMR) allows to obtain 3D geometry, 4D flow data and regional aortic stiffness.

Purpose

We aim to study regional aortic curvature in thoracic aorta aneurysms of different aetiologies and define its relationship with established risk factors.

Methods

One-hundred twenty patients (40 for each group, selected out of prospective cohorts of 156 bicuspid aortic valve – BAV-, 77 Marfan –MFS- and 67 patients with a degenerative aneurysm – TAVdeg-) were matched for age, sex and BSA via propensity score with 40 healthy volunteers (HV). The thoracic aorta was semi-automatically segmented from angiograms and the centreline was computed. Local curvature was assessed at 20 planes covering the thoracic aorta from the sinotubular junction to the proximal descending aorta (DAo) at the level of the pulmonary artery bifurcation. Local curvature was normalized by subject mean thoracic aorta curvature. Length was measured as centreline length. Aortic stiffness was measured in the DAo by pulse wave velocity (PWV). Aneurysm was defined by z-score ≥ 2 using diameters measured by double-oblique cine CMR.

Results

Matching was successful in all groups with the exception of a residual age difference between HV and TAVdeg. Curvature in HV showed a fairly smooth transition between the straighter ascending aorta (AAo) and DAo to a more curved aortic arch, with a peak in the mid aortic arch (Figure 1A).  Conversely, all patients’ groups presented a peak in curvature in the proximal DAo and a decreased local curvature in the aortic arch and mid DAo close to the level of the pulmonary artery. BAV and TAVdeg patients showed also increased curvature in the mid AAo, were dilation is prevalent. Conversely, in the same area MFS showed a reduced curvature and limited prevalence of aneurysm. In the overall population, age, AAo and root diameters, mean blood pressure, DAo PWV and aortic length, all established risk factors for aortic events, were inversely related to curvature in the distal AAo and aortic arch (Figure 1B).

Conclusions

Aneurysms related to different aetiologies show similar abnormalities in aortic curvature, with limited curvature in the aortic arch and a peak soon after the third supra-aortic vessel. Age, aortic diameter, length, stiffness and blood pressure, all known risk factors, are all related to reduced curvature in the distal ascending aorta and aortic arch.

Abstract Figure.

Reinforcement machine learning-based aortic anatomical landmarks detection from phase-contrast enhanced magnetic resonance angiography

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Science, Innovation and Universities; La Marató de TV3

Introduction

Automatic analysis of medical imaging data may improve their clinical impact by reducing analysis time and improving reproducibility. Many medical imaging data, like 4D-flow magnetic resonance imaging (MRI), are often quantified regionally, implying the need for anatomical landmark identification to locate correspondences in the extracted data and compare among patients. Machine learning (ML) techniques hold potential for automatic analysis of medical imaging. Phase-contrast enhanced magnetic resonance angiography (PC-MRA) is a class of angiograms not requiring the administration of contrast agents.

Purpose

We aimed to test whether a machine learning algorithm can be trained to identify key anatomical cardiovascular landmarks on PC-MRA images and compare its performance with humans.

Methods

Three-hundred twenty-three aortic PC-MRA were manually annotated with the location of 4 landmarks: sinotubular junction, pulmonary artery bifurcation and first and third supra-aortic vessels (Figure 1), often used to separate the aorta in sub-regions. Patients included in the training dataset comprised healthy volunteers (40), bicuspid aortic valve patients (141), patients with degenerative aortic disease (60) and patients with genetically-triggered aortic disease (82), all without previous aortic surgery and with native aortic valve. PC-MRA images and manual annotations were used to train a DQN, a reinforcement learning algorithm that combines Q-learning with deep neural networks. The agents can navigate the images and optimally find the landmarks by following the policies learned during training. Data from thirty patients, distributed in terms of aortic condition as the training set, unseen by the algorithm in the training phase, were used to quantify intra-observer reproducibility and to assess ML algorithm performance. Distance between points was used as metric for comparisons, original human annotation was used as ground-truth and repeated-measures ANOVA was used for statistical testing.

Results

Human and machine learning performed similarly in the identification of the sinotubular junction (distance between points of 11.0 ± 8.1 vs. 11.1 ± 8.6 mm, respectively, p = 0.949) and first (6.6 ± 3.9 vs. 6.8 ± 5.6 mm, p = 0.886) and third (6.8 ± 4.0 vs. 8.4 ± 7.4 mm, p = 0.161) supra-aortic vessels branches but human annotation outperformed ML landmark detection in the identification of the pulmonary artery bifurcation (10.2 ± 7.0 vs. 15.2 ± 13.1 mm, p = 0.008). Computation time for landmark detection by ML was between 0.8 and 1.6 seconds on a standard computer while human annotation took approximatively two minutes.

Conclusions

ML-based aortic landmarks detection from phase-contrast enhanced magnetic resonance angiography is feasible and fast and performs similarly to human. Reinforced learning anatomical landmark identification unlock automatic extraction of a variety of regional aortic data, including complex 4D flow parameters.

Abstract Figure

Investigation of boron carbide and iridium thin films, an enabling technology for future x-ray telescopes

We present an experimental examination of iridium and boron carbide thin-film coatings for the purpose of fabricating x-ray optics. We use a combination of x-ray reflectometry and x-ray photoelectron spectroscopy to model the structure, composition, density, thickness, and micro-roughness of the thin films. We demonstrate in our analyses how the two characterization techniques are complementary, and from this we derive that an overlayer originating from atmospheric contamination with a thickness between 1.0-1.6 nm is present on the surface. The magnetron sputtered iridium films are measured to have a density of 22.4g/cm³. The boron carbide film exhibits a change in chemical composition in the top ∼2nm of the film surface when exposed to the ambient atmosphere. The chemical reaction occurring on the surface is due to an incorporation of oxygen and hydrogen present in the ambient atmosphere. Lastly, we present a correlation between the absorption edges and the emission lines exhibited by the thin films in an energy range from 50-800 eV and the impact on the reflectivity performance due to contamination in thin films.

Long term outcomes in left ventricular non-compaction

Background

Left ventricular non-compaction (LVNC) is a highly heterogeneous entity with a wide phenotypic expression. Risk factors have not been well established and prognostic stratification remains challenging.

Objectives

Describe long term outcomes of LVNC patients and determine predictors of cardiovascular events.

Methods

Prospective multicentric study of consecutive patients fulfilling imaging criteria for LVNC. Demographic, ECG, imaging and genetic variables were collected. End points were heart failure (HF), ventricular arrhythmias (VA), systemic embolisms (SE) and all-cause death. Major adverse cardiovascular event (MACE) was described as the combination of the four previous end points.

Results

592 patients from 13 referral centres were included from 2000 to 2018. Mean age at diagnosis was 45 years, 252 (43%) were female and mean LVEF was 48% (Table 1). During a median follow-up of 55 months (IQR 24–90), 144 (25%) patients presented HF, 101 (18%) VA, 27 (5%) SE and 33 (6%) died. MACE occurred in 223 (39%) patients.

In multivariate analysis, independent predictors of HF were LVEF (OR 0.9), PSAP (OR 1.17) and late gadolinium enhancement (LGE) (OR 1.3). VA were independently associated with LVEF (OR 0.97) and LGE (OR 2.51). Independent predictors of SE were LVEF (OR 0.96) and LA diameter (OR 1.07). No independent predictors of all-cause death could be described. MACE were independently associated with LVEF (OR 1.04) and PSAP (OR 1.08) (Table 1).

Among patients who underwent genetic testing (340, 57%), genotype was associated with outcomes: MYH7 and ACTC1 variants were protective while multiple mutations, TTN and MYBPC3 variants exhibited worse prognosis.

Conclusions

In a large prospective multicentric cohort of LVNC patients, there was a moderate long term incidence of cardiovascular events. LVEF and fibrosis were the main predictors and genotype was a modifier of outcomes. These factors might be used to risk stratify LVNC patients.

Funding Acknowledgement

Type of funding source: None

Relationship between aortic distensibility and aortic regurgitation depending on aortic valve anatomy. A CMR study

Background

Aortic regurgitation (AR) can be evaluated by cardiac magnetic resonance (CMR).The most commonly used method to quantify AR is direct measurement using phase contrast (PC) imaging, at the aortic root (as close as possible to the aortic valve), for the calculation of regurgitant fraction (RF). Aortic distensibility (AD) may affect aortic valve dynamics and, as a result, aortic regurgitation grade. However, the impact of aortic distensibility in this evaluation remains unknown.

Purpose

The aim of the study was to evaluate the relationship between AD and AR in patients with different aortic valve anatomy.

Methods

213 patients with different AR severity grades and aortic valve anatomy (tricuspid (TAV) and bicuspid valve (BAV) patients) were enrolled (32.2% female, 74% BAV, 55.5±15.4 years), excluding connective tissue disease. All patients underwent a CMR study with PC sequences for the evaluation of regurgitant fraction at the aortic valve level. AR was considered as mild (&lt;15%), moderate (15–30%) or severe (&gt;30%) depending on RF value. Furthermore we used cine-sequences to estimate aortic diameters and distensibilities, using Art Fun software. Distensibility was calculated as (change in aortic area between systole and diastole/diastolic area)/brachial pulse pressure.

Results

159 (73.7%) AR were mild, 30 (14.1%) moderate and 24 (11.3%) severe. RF significantly correlated with aortic root diameter (r=0.337, p&lt;0.001) and did not correlate with AD at the level of proximal descending aorta (r=0.121 and p=0.107). Furthermore descendig aorta distensibility correlated with age (r=−0.631, p&lt;0.001) and aortic root diameter (r=−0.224, p=0.002). Dividing population in two different groups, depending on aortic valve anatomy, in TAV patients RF continued to not correlate with AD (r=0.159, p=0.369). In contrast, RF in BAV patients was positively correlated with AD (r=0.223, p=0.007) even after adjustment for aortic diameter and age in a multiple regression model (p&lt;0.001, R2=0.478).

Conclusions

In our study, aortic regurgitation is positively related to descending aorta distensibility in BAV patients, regardless of age and aortic root diameter. Thus, AD may play a role in the evaluation of AR in case of bicuspid valves. In contrast, in TAV patients, distensibility does not seem to influence the assessment of AR severity.

Descending aorta distensibility

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Research grant provided by the Cardiopath PhD program

Aortic stiffness and hemodynamics in Loeys-Dietz syndrome by 4Dflow CMR: a comparison with healthy volunteers and patients with Marfan syndrome

Background

Connective tissue disorders, such as Loeys-Dietz (LDS) and Marfan (MFS) syndromes, are rare genetic diseases associated with progressive aortic dilation. Aortic dissections have been observed at lower aortic root diameters in LDS than in MFS, and research on aortic flow dynamics and biomechanics in LDS is lacking.

Purpose

To evaluate rotational aortic flow and aortic stiffness in LDS compared to healthy volunteers (HV) and MFS patients, using 4Dflow CMR.

Methods

Twenty-one LDS and 44 MFS patients, without previous aortic dissection or surgery, and 44 HV underwent a non-contrast-enhanced 4D flow CMR. In-plane rotational flow (IRF), systolic flow reversal ratio (SFRR) and local aortic diameters were obtained at 20 equidistant planes from the ascending (AAo) to the proximal descending aorta (DAo). Aortic stiffness was quantified at the AAo and DAo using pulse wave velocity (PWV).

Results

LDS patients had lower IRF at the distal AAo and proximal DAo compared to HV (p=0.053 and 0.004, respectively), once adjusted for age, stroke volume and local aortic diameter; but no differences were found with respect to MFS (Figure). Although SFRR at the proximal DAo was increased in LDS patients compared to both HV (p=0.037) and MFS populations (p=0.015), once adjusted for age and aortic diameter, the difference in magnitude was small (Figure). On the other hand, AAo and DAo PWV revealed stiffer aortas in LDS patients compared to HV but no differences versus MFS patients (Table).

Conclusions

LDS patients showed decreased in-plane rotational flow and abnormally-high regional aortic stiffness compared to healthy controls, and similar hemodynamics and aortic stiffness with respect to MFS patients

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Instituto de Salud Carlos III, La Maratό TV3

Patients with blunt traumatic thoracic aortic injury treated with TEVAR present increased flow dynamics alterations and pulse wave velocity: a 4D flow CMR study

Background

Thoracic endovascular aortic repair (TEVAR) is widely used for the treatment of blunt traumatic thoracic aortic injuries. Aortic flow dynamics and mechanical implications of this intervention are poorly investigated and may be of particular interest in the long-term follow-up of these mostly young patients.

Purpose

To assess whether the presence of TEVAR in a cohort of otherwise healthy subjects was related to dilation of the proximal aorta or increase in aortic stiffness and flow alterations.

Methods

Nineteen patients who underwent TEVAR implantation after a traumatic injury of the thoracic descending aorta (DAo) (10.0±6.1 years from intervention) and 44 healthy volunteers (HV) underwent 4D flow CMR to compute ascending aorta (AAo) pulse wave velocity (PWV), a marker of aortic stiffness, systolic flow reversal ratio (SFRR), quantifying backward flow during systole and in-plane rotational flow (IRF), measuring in-plane strength of helical flow. IRF and SFRR were assessed at 20 planes between the sinotubular junction and the mid thoracic DAo. Aortic diameters were measured using double-oblique cine CMR.

Results

Patients with TEVAR and HV did not differ in age, sex, body surface area, blood pressure and DAo diameter distal to TEVAR (Table). However, TEVAR patients presented larger diameters at the sinus of Valsalva and AAo, increased AAo PWV and strong flow alterations: IRF was reduced from the distal AAo to the proximal DAo, while SFRR was increased in the whole thoracic aorta (Figure).

Conclusions

In patients with blunt traumatic thoracic aortic injury treated with TEVAR the aorta proximal to TEVAR is dilated, stiffer and present potentially pathogenic flow conditions. Longitudinal studies are needed to assess whether these alterations have prognostic value and may improve clinical prevention and management of these patients.

Figure 1. IRF and SFRR in healthy vs TEVAR

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study has been funded by Instituto de Salud Carlos III, Spanish Ministry of Science and Innovation (PI19/01480). Guala A. received funding from the Spanish Ministry of Science, Innovation and Universities (IJC2018-037349-I).

The length of the fusion between leaflets in bicuspid aortic valve is independently related to ascending aorta dilation and flow dynamics alterations assessed by 4D-flow CMR

Background

Aortic dilation in bicuspid aortic valve (BAV) patients has been related to altered flow patterns, which contribute to aortic wall degeneration. However, preventive aortic replacement is currently based on a diameter threshold. Several studies on excised BAV reported wide variability of fusion extent.

Purpose

To unveil whether leaflet fusion extent can be quantified by CMR and is related to aortic dilation and flow abnormalities in non-dysfunctional BAV.

Methods

One hundred and twenty adults with non-dysfunctional BAV and no previous aortic or aortic valve surgery and 28 healthy volunteers underwent double-oblique cine and 4D flow CMR. BAV patients with two sinuses of Valsalva or left and non-coronary cusps fusion were excluded. Peak systolic circumferential wall shear stress (WSSc) and pulse wave velocity (PWV) in the ascending aorta (AAo) were assessed by 4D flow CMR. Fusion length between leaflets was measured using a stack of double-oblique cine CMR images of the aortic valve.

Results

The length of the fusion was effectively measured in 112/120 (93%) patients with good reproducibility (ICC = 0.826) and showed great variability (range 2.3–15.4 mm, 7.8±3.2 mm and tertiles cut-off points 6 and 9.3 mm). In multivariate analysis adjusted for clinical and demographic characteristics and PWV, fusion length was independently associated with the diameter at the sinus of Valsalva (p=0.002) and the AAo (p=0.02) (Table). WSSc progressively increased with larger fusion length (Figure), with statistical significance (p&lt;0.05) in the right and outer regions of the proximal and mid AAo.

Conclusions

Bicuspid aortic leaflet fusion length varies considerably, and it is independently associated with AAo and aortic root dilation, possibly through flow alterations.

Figure 1. Maps of circumferential WSS

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study has been partially funded by Instituto Carlos III, Spanish Ministry of Science and Innovation (PI17/00381). Guala A. has received funding from the Spanish Ministry of Science, Innovation and Universities (IJC2018-037349-I).

The role of descending aorta diastolic reverse flow in the quantification of aortic regurgitation by CMR

Background

EACVI recommends the use of an “integrative approach”, using several parameters, in aortic regurgitation (AR) quantification. This approach is easily achieved by echocardiography although cardiovascular magnetic resonance (CMR) remains the gold standard for the quantification of regurgitant fraction (RF).

Purpose

The aim of the study was to analyze the accuracy of descending aorta (DA) diastolic reverse flow in the assessment of chronic AR severity by CMR to identify an additional parameter.

Methods

188 patients (34% female, 54.6±15.6 years) with different severity grades of chronic AR were enrolled. All patients underwent a CMR study. Aortic regurgitation was considered as absent (≤1%), mild (≤15%), moderate (≤15%) or severe (≥30%) depending on RF value at valve level. Furthermore, cine-sequences were used to estimate aortic diameters and distensibilities using Art Fun software. Velocity-time integral (VTI) of reverse flow in DA was calculated from maximum velocity curves by an in-house MatLab code.

Results

AR was absent in 21 (12%) patients, mild in 114 (62.9%), moderate in 23 (12.7%) and severe in 21 (11.6%).DA VTI reverse flow was significantly higher as was the RF at valve level (r=0.805, p&lt;0.001) (IMG, Table). It also positively correlated withaortic root diameter (r=0.347, p&lt;0.001) and DA distensibility (r=0.279, p&lt;0.001). It did not correlate with age (r=−0.91, p=0.22). In a statistically significant multiple regression model (p&lt;0.001, R2 = 0.697), although VTI reverse flow in DA correlated strongly with RF at valve level (p&lt;0.001; beta = 0.733), it was also influenced by DA distensibility (p&lt;0.001; beta = 0.197) and aortic root diameter (p&lt;0.001; beta= 0.140).

Conclusions

VTI reverse flow in DA correlates strongly with the degree of AR and may be useful in the assessment of its severity. Neverthless, owing to the influence of other factors (aortic distensibility and aortic root diameter), it cannot be used as a single parameter in the quantification of AR severity by CMR.

Scatter Plot graphs

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): research grant provided by the Cardiopath PhD program

Prognostic value of odor identification impairment in multiple sclerosis: 10-Years follow-up

BACKGROUND

Olfactory dysfunction has been linked to clinical severity variables in multiple MS populations. Though, its prognostic value is still unknown.

OBJECTIVE

The aim of this study was to explore the long-term outcome associated with Brief-Smell Identification Test (B-SIT) performance in a cohort of MS patients.

METHODS

A retrospective review of the clinical records was conducted in 149 patients who participated in a previous study, with a median follow-up of 121 months. Demographic and clinical data regarding the last clinical appointment with EDSS measurement were collected. Multiple Sclerosis Severity Scale (MSSS) and Age-Related Multiple Sclerosis Severity (ARMSS) scores were calculated. Date of the last clinical contact or death was recorded.

RESULTS

Among MS patients with progressive clinical course (n = 33), those with impaired B-SIT at baseline had greater change per month during follow-up (as measured by increases in MSSS and ARMSS scores) and a higher hazard of death. No significant associations were found among patients with relapsing and remitting MS (n = 116).

CONCLUSIONS

The study results demonstrate that odor identification impairment has prognostic value in progressive MS, suggesting that a brief odor identification measure can be a marker of neurodegeneration in progressive MS.

Assessing fitness to drive: Knowledge and practices from medical doctors and psychologists

Introduction Medical and psychological assessment of fitness to drive is a professional activity performed in a large number of candidates and drivers to validate a driving license. Medical doctors and psychologists are responsible to assess medical and psychological abilities for driving, respectively. Despite the legal framework for assessing fitness to drive on each country, the knowledge and practices among professionals may vary.

Objectives To examine the knowledge and practices of Portuguese medical doctors and psychologists concerning the assessment of fitness to drive.

Methodology Two online questionnaires, one version for medical doctors and another for psychologists, were designed to measure self-reported knowledge and practices towards assessment of fitness to drive. The questionnaires were disseminated by e-mail to a non-probability sample, responding 273 participants, including 128 medical doctors and 145 psychologists.

Results In the sample of medical doctors, 49% recognized themselves as not qualified to do a medical assessment of fitness to drive, 40% reported lack of knowledge about the related legislation and the majority (83%) feel that would benefit from further education in this area. Concerning psychologists, 52.4% judged themselves as not qualified for psychological assessment for driving, 49.7% recognized lack of knowledge about the legislation and 70% would like to do training in this area. Both groups pointed lack of knowledge about several parameters such as mandatory assessments and periods, professional responsibilities and assessment methods.

Conclusion Medical doctors and psychologists highlighted lack of knowledge and confidence to practice assessments of fitness to drive. Academic education and training needs are pointed in order to improve the professional practices in those assessments with potential impact on road safety and public health.

P1441 Predictors of systemic embolisms in a large cohort of left ventricular noncompaction patients

BACKGROUND

Left ventricular noncompaction (LVNC) is associated with an increased risk of systemic embolisms (SE). However, incidence and risk factors are not well established.

PURPOSE

To evaluate the rate of SE in LVNC and describe risk factors.

METHODS

LNVC patients were included in a multicentric registry. Those with SE were considered for the analysis.

RESULTS

514 patients with LVNC from 10 Spanish centres were recruited from 2000 to 2018. During a median follow-up of 4.2 years (IQR 1.9-7.1), 23 patients (4.5%) had a SE. Patients with SE (Table 1) were older at diagnosis, with no differences in gender and had similar cardiovascular risk factors. They were more frequently under oral anticoagulation (OAC). Besides, they had a more reduced LVEF, and more dilated LV and left atrium (LA). Late gadolinium enhancement (LGE) was more frequent, altogether suggesting a more severe phenotype.

Patients with SE had non-significantly higher rates of hospitalization for heart failure (33% Vs 24%, p = 0.31) and atrial fibrillation (35% Vs 19%, p = 0.10). In multivariate analysis, only LA diameter was an independent predictor of SE (OR 1.04, p = 0.04). A LA diameter &gt; 45 mm had an independent 3 fold increased risk of SE (OR 3.04, p = 0.02) (Image 1).

CONCLUSIONS

LVNC carries a moderate mid-term risk of SE, which appears to be irrespective of atrial fibrillation and associated with age, LV dilatation and systolic dysfunction and mainly LA dilatation. This subgroup of patients should be considered for oral anticoagulation in primary prevention.

Table 1 Systemic embolisms (n = 23) No systemic embolisms (n = 491) p Men, n (%) 15 (65) 289 (56) 0.52 Median age at diagnosis (IQR) - yr 60 (48-76) 48 (30-64) 0.02 Median follow up (IQR) - yr 5.9 (3.1-7.8) 4.2 (1.8-7.1) 0.18 OAC, n (%) 19 (83) 118 (24) 0.01 LVEF (SD) - % 37 (15) 48 (17) 0.01 LVEDD (SD) - mm 58 (11) 54 (10) 0.04 LA diameter (SD) - mm 46 (9) 39 (9) 0.01 Characteristics of patients with and without systemic embolisms

Abstract P1441 Figure. Image 1

P372 Aortic stiffness in Loeys-Dietz syndrome: a comparison with Marfan syndrome patients and healthy volunteers

Funding Acknowledgements

ISCIII PI14/0106 and PI17/00381, La Marató de TV3 (20151330), Eur FP7/People 267128 and CIBERCV

BACKGROUND

Genetic syndromic aortic diseases are rare, with Marfan syndrome (MFS) being the most common. However, less is known of Loeys-Dietz syndrome (LDS) which has much lower prevalence and presumed worse prognosis. Increased aortic stiffness in MFS has been previously described but no studies have evaluated aortic biomechanics in LDS. Pulse wave velocity (PWV) is the gold standard measure for arterial stiffness and can be quantified by 4D flow MRI. We aim to evaluate regional aortic PWV by 4D flow MRI in LDS compared to MFS and healthy volunteers.

METHODS

Sixteen LDS patients with a pathogenic mutation, 76 MFS and 49 healthy volunteers were prospectively and consecutively included. No patient had previous aortic dissection or surgery. All underwent a 4D flow MRI study in a 1.5 T clinical scanner. Ascending (AAo) and descending (DAo) aorta PWV were computed using wavelet analysis of the systolic upslope for transit time calculation (Figure). Statistical comparison was made with non-parametric analysis to account for the non-normality of data and multivariate analysis was evaluated separately for AAo and DAo PWV.

RESULTS

Ascending and descending aortic PWV revealed stiffer aortas in LDS patients than in healthy volunteers, even after adjustment for diameter of sinus of Valsalva (SoV) and sex. Conversely, no differences in aortic stiffness were found between LDS and MFS patients (Table).

CONCLUSIONS

Abnormally high regional aortic stiffness was observed in LDS patients when compared with controls. The severity of increased regional aortic stiffness was found similar to the one affecting MFS patients.

Table Controls (N = 49) LDS (N = 16) MFS (N = 76) LDS vs. HV LDS vs. MFN Parameter Unadjusted p-value Adjusted p-value Unadjusted p-value Adjusted p-value Age [years] 39 ± 12 39 ± 16 36 ± 12 0.903 0.599 Men 32 (65%) 6 (37%) 34 (45%) 0.079 0.782 Weight [kg] 72 ± 11 69 ± 13 74 ± 16 0.288 0.194 Height [cm] 172 ± 8 172 ±12 181 ± 11 0.834 0.008 Systolic BP [mmHg] 126 ± 18 125 ± 14 127 ± 17 0.957 0.523 Diastolic BP [mmHg] 70 ± 11 77 ± 6 75 ± 12 0.011 0.318 SoV diameter [mm] 30.6 ± 3.9 35.4 ± 4.6 38.1 ± 5.9 0.001 0.060 AAo diameter [mm] 27.7 ± 3.8 29,0 ± 5.0 29.7 ± 5.4 0.458 0.579 DAo diameter [mm] 20.0 ± 2.0 21.3 ± 3.6 22.9 ± 3.8 0.546 0.124 AAo PWV [m/s] 5.2 ± 1.9 7.6 ± 2.4 7.3 ± 2.8 0.001 0.050* 0.534 NS DAo PWV [m/s] 7.1 ± 2.2 9.4 ± 2.6 10.7 ± 4.6 0.003 0.025** 0.493 NS

Abstract P372 Figure

P1600 Aortic dilatation in patients with chronic descending aorta dissection is related to maximum false-lumen systolic flow deceleration rate as evaluated by 4D-flow MRI

Background

Due to improved surgical strategies a growing number of patients survive acute aortic dissection. Patent false lumen (FL) is common in chronic dissection and it has been associated with poor prognosis, which is mainly driven by FL expansion. Several variables indirectly related to flow characteristics have been associated with progressive aortic dilation. We aimed to evaluate whether the maximum systolic flow deceleration rate (MSDR) in the FL, quantified by 4D-flow MR, is related to FL dilation in chronic type B aortic dissection.

Methods

Twenty-nine patients with a patent FL after aortic dissection and a prior follow-up of at least 3 years underwent contrast-enhanced 4D-flow MR. Marfan patients were excluded. Time-resolved FL flow acceleration was calculated in a 5 cm-long volume of the descending aorta around the level of the pulmonary bifurcation. MSDR was determined as the maximum minus the minimum acceleration in systole over the corresponding time interval (Figure 1a). Aortic growth rate (GR) was measured as the difference between final and initial maximum FL diameters obtained by angio-CT divided by follow-up duration. Population was divided into tertiles based on GR.

Results

Demographic and clinical variables were similar among GR tertiles (Table). MSDR was lower in patients with a GR &lt;1mm/year (group 1) compared to both the other two patient groups (p = 0.009 and 0.003 for groups 2 and 3, respectively) (Figure 1c). MSDR showed a marked positive linear correlation with GR (R = 0.481, p = 0.008) (Figure 1b).

Conclusions

The MSDR in the FL of chronic type B aortic dissection is linearly related to FL growth rate and discriminated between tertiles of aortic dilation. Prospective longitudinal studies are need to unveil possible prognostic value of this parameter.

Table Group 1 (n = 9) Group 2 (n = 10) Group 3 (n = 10) p-value Age (years) 63.44 ±13.54 62.50 ± 13.60 64.56 ± 6.67 0.902 BSA (m2) 2.00 ± 0.18 1.77 ± 0.20 1.94 ± 0.12 0.213 Men 6 (86%) 4 (57%) 4 (100%) 0.210 Hypertension 4 (66%) 5 (71%) 4 (100%) 0.438 Atheroclerosis 1 (17%) 1 (14%) 0 (0%) 0.699 Initial Diameter (mm) 45.00 ± 7.69 36.00 ± 4.20 37.00 ± 6.48 0.078 Final Diameter (mm) 49.50 ± 6.74 44.86 ± 5.70 59.25 ± 9.84 0.049 Follow-up (year) 11.83 ± 8.79 7.82 ± 3.34 8.08 ± 4.05 0.921 GR (mm/year) 0.27 ± 0.29 1.18 ± 0.26 2.64 ± 0.97 &lt;0.001 MSDR (cm/s3) 1212.18 ± 467.61 2410.54 ± 1034.30 2558.16 ± 1098.06 0.005

Abstract P1600 Figure 1

P1442 Outcomes of patients with left ventricular noncompaction and preserved ejection fraction

CONCLUSIONS

Patients with LVNC and pEF have an overall excellent prognosis, which is markedly better than those with rEF. However, there is progressive decrease in LVEF, associated with heart failure, and moderate risk of life threatening arrhythmias. Therefore, periodic follow-up should be promoted.

Table 1 LVNC pEF (n = 239) LVNC rEF (n = 252) p Men, n (%) 131 (55) 146 (58) 0.65 Median age at diagnosis (IQR) - yr 38 (23-54) 58 (42-72) 0.01 Median follow up (IQR) - yr 4.9 (2.1-7.3) 3.9 (1.4-7.9) 0.04 QRS (SD) - ms 93 (18) 117 (32) 0.01 LGE, n (%) 18 (9) 52 (30) 0.01

Abstract P1442 Figure. Image 1

P1601 Relationship between aortic distensibility and aortic regurgitation assessed by CMR in bicuspid valve patients

Funding Acknowledgements

Spanish Ministry of Economy and Competitiveness RTC-2016-5152-1, ISCIII PI17/00381, La Marató de TV3 (20151330), Eur FP7/People 267128 and CIBERCV

BACKGROUND

The severity of aortic regurgitation can be evaluated with cardiac magnetic resonance (CMR) through calculation of regurgitant fraction (RF) in phase contrast sequences acquired at the aortic root (as close as possible to the aortic valve). However, the impact of aortic distensibility in this evaluation remains unkown.

PURPOSE

The aim of the study was to evaluate the relation between aortic distensibility and RF valve in bicuspid aortic valve patients.

METHODS

We enrolled bicuspid aortic valve patients without significant aortic stenosis (maximum velocity &lt;2.5 m/s) and connective tissue disease. All patients underwent a CMR study with phase contrast sequences for evaluation of regurgitant fraction at the level of the aortic valve. Aortic regurgitation was considered as mild, moderate or severe depending on RF value (mild &lt;15%; moderate 15-30%; severe &gt;30%). Furthermore we used cine-sequences of aortic root, ascending and proximal descending aorta to estimate aortic diameters and distensibilities, using Art Fun software. Distensibility was calculated as (change in aortic area between systole and diastole/diastolic area)/brachial pulse pressure.

RESULTS

A total of 98 bicuspid aortic valve patients were included (30% female, 49.7 ± 14.5 years). 75 (76,5%) AR was mild, 17 (17,4%) moderate and 6 (6,1%) severe. RF valvewas significantly correlated with aortic root diameter (r= 0.430 y p &lt; 0.001 )and aortic distensibility at the level of the ascending (r = 0.273 p =0.016) and descending aorta (r = 0.502 and p&lt; 0.001). Aortic distensibility was positively correlated with RFvalve even after adjustment for aortic diameter ( p = 0.002 and p &lt;0.001 respectively) . (Table) (IMG)

CONCLUSIONS

In our study, aortic regurgitation in bicuspid valve patients, evaluated by CMR using RF valve, is related to aortic distensibility. Thus, aortic distensibility should be included in the evaluation of aortic regurgitation by CMR as additional parameter. However, longitudinal studies are needed to evaluate the impact of including aortic distensibility in the evaluation of AR severity by CMR.

AR SEVERITY MILD MODERATE SEVERE Descending aorta distensibility(mean ± std. deviation) 2693,68 ± 997,5 3285,8 ±1952,7 5042,99 ±2873,44 Correlation between AR severity (by RFvalve) and descending aorta distensibility

Abstract P1601 Figure.

Simulated root canals preparation time, comparing ProTaper Next and WaveOne Gold systems, performed by an undergraduate student

Background

The aim of this study was to compare the WaveOne Gold and ProTaper Next systems regarding the time spent preparing simulated canals performed by an inexperienced student.

Material and Methods

0 simulated L-shaped canals were randomly divided into two groups (n = 40) and numbered in order of instrumentation. Canals were instrumented with WaveOne Gold (group 1) and ProTaper Next (group 2) systems. The effective instrumentation time and the number of instrumentation cycles were recorded. All procedures were performed by the same operator. Statistical analysis was obtained by the Mann - Whitney, Kruskal - Wallis test with significance of p<0.05.

Results

There were no statistically significant differences regarding the mean instrumentation time between the two instrumentation systems. The instrumentation time decreased over the experimental period, regardless of the technique used.

Conclusions

Through a short learning curve, an inexperienced operator can prepare simulated canals in a very predictable time. Time spent was similar in a multi-file instrument system (ProTaper Next) and a single-file system (WaveOne Gold).

Key words:Dental education, endodontics, preclinical, root canal preparation, undergraduate.

P1447 Ascending aorta longitudinal strain in bicuspid aortic valve patients: a comparison with healthy volunteers and patients with degenerative aortic aneurysm

Funding Acknowledgements

Spanish Ministry of Economy and Competitiveness RTC-2016-5152-1, ISCIII PI17/00381, La Marató de TV3 (20151330), Eur FP7/People 267128 and CIBERCV

Background

Histological findings of fibrillin-1 deficiency in bicuspid aortic valve (BAV) ascending aorta (AAo), as observed in Marfan (MFS), supported the existence of intrinsic aortic wall abnormalities, but recent studies reported the absence of an intrinsic impairment in stiffness. A recent study in MFS showed that AAo longitudinal strain was reduced in MFS and predicted dilation and aortic events. This parameter has not been studied in BAV.

Purpose

We investigated whether ascending aorta longitudinal strain is intrinsically altered in BAV with respect to tricuspid aortic valve (TAV) individuals.

Methods

80 BAV, 31 healthy volunteers (HV) and 29 TAV with AAo aneurysm, all without moderate valvular disease, were consecutively included. AAo dilation was defined as a z-score &gt; 2. The 1.5T CMR protocol included a set of 2D cine CMR stacks covering the proximal aorta in saggital, coronal and axial views. AAo longitudinal strain was computed by an in-house Matlab code performing a feature tracking of the aortic valve in each of the cine images.

Results

Twenty (25%) of BAV had AAo dilation. AAo longitudinal strain was lower in non-dilated BAV compared to HV, but the difference was not significant in multivariate analysis adjusted for AAo diameter and systolic blood pressure. Similarly, the difference between dilated BAV and dilated TAV found in univariate analysis was not confirmed by multivariate analysis. On the other hand, both dilated BAV and TAV showed decreased AAo longitudinal strain compared to HV, which were confirmed in multivariate analyses.

Conclusions

AAo longitudinal strain, a marker of aortic stiffness with predictive value in MFS, is not altered in BAV patients compared to TAV matched for dilation prevalence. Reduced AAo longitudinal strain was independently associated with dilation in both BAV and TAV.

Table 1 HV vs. NON-DILATED BAV DILATED BAV vs DILATED TAV HV vs. DILATED BAV HV vs. DILATED TAV HV NON-DILATED BAV Univariate /multivariate p-value DILATED TAV DILATED BAV Univariate /multivariate p-value Univariate/ Multivariate p-value Univariate p-value N 31 20 29 60 Age [years 35 ± 8 49 ± 16 &lt;0.001/ NS 66 ± 13 49 ± 14 &lt;0.001 / &lt;0.001 &lt;0.001 / 0.052 &lt;0.001 / NS Sex [% male] 42 35 0.629 24 42 0.097 / NS 0.969 0.149 BSA [m2] 1.83 ± 0.17 1.81 ± 0.14 0.702 1.95 ± 0.24 1.82 ± 0.22 0.015 / &lt;0.001 0.881 0.030 / NS SBP [mmHg] 119 ± 11 132 ± 16 0.002 / 0.029 133 ± 17 138 ± 19 0.304 &lt;0.001 / NS &lt;0.001 / NS DBP [mmHg] 69 ± 11 73 ± 6 0.099 / NS 77 ± 9 79 ± 11 0.455 &lt;0.001 / 0.016 0.004 / 0.023 Ascending aorta diameter [mm] 26 ± 4 33 ± 3 &lt;0.001 / 0.006 46 ± 7 43 ± 6 0.032 / NS &lt;0.001 / 0.001 &lt;0.001 /0.007 AAo long strain [%] 10.5 ± 3.6 8.4 ± 4.1 0.067/ NS 5.9 ± 2.7 7.7 ± 3.6 0.023 / NS 0.001 / 0.002 &lt;0.001 / 0.023 Demographics and uni- and multivariate analyses of AAo longitudinal strain

Determination of Immunoglobulin G in Bovine Colostrum and Milk Powders, and in Dietary Supplements of Bovine Origin by Protein G Affinity Liquid Chromatography: Collaborative Study

An AOAC collaborative study was conducted to evaluate an affinity LC procedure for measuring immunoglobulin G (IgG) in selected dairy powders. The powders were extracted with 0.15 M sodium chloride solution and the pH was adjusted to 4.6 to precipitate caseins, which would otherwise lead to an overestimation of IgG. The analyte was then bound to a commercially available Protein G affinity cartridge and selectively eluted with a glycine buffer at pH 2.5. Detection was at 280 nm and quantification was made against a calibration curve prepared from bovine serum IgG. The samples analyzed included the likely matrixes for which this assay will find commercial use, namely, high- and low-protein-content colostrum powders, tablets containing colostrum powder, and some IgG-containing dairy powders; milk protein isolate, whey protein concentrate, and skim milk powder. Eleven laboratories provided data for the study and assayed blind duplicates of six materials. The repeatability RSD values ranged from 2.1 to 4.2 and the reproducibility RSD values ranged from 6.4 to 18.5. The Protein G method with casein removal has adequate reproducibility for measuring IgG in colostrum-derived powders that are traded on the basis of IgG content as a colostral marker.

Synthesis of thermoelectric magnesium-silicide pastes for 3D printing, electrospinning and low-pressure spray

In this work, eco-friendly magnesium-silicide (Mg₂Si) semiconducting (n-type) thermoelectric pastes for building components concerning energy-harvesting devices through 3D printing, spray and electrospinning were synthetized and tested for the first time. The Mg₂Si fine powders were obtained through the combination of ball milling and thermal annealing under Ar atmosphere. While the latter process was crucial for obtaining the desired Mg₂Si phase, the ball milling was indispensable for homogenizing and reducing the grain size of the powders. The synthetized Mg₂Si powders exhibited a large Seebeck coefficient of ~ 487 µV/K and were blended with a polymeric solution in different mass ratios to adjust the paste viscosity to the different requirements of 3D printing, electrospinning and low-pressure spray. The materials produced in every single stage of the paste synthesis were characterized by a variety of techniques that unequivocally prove their viability for producing thermoelectric parts and components. These can certainly trigger further research and development in green thermoelectric generators (TEGs) capable of adopting any form or shape with enhanced thermoelectric properties. These green TEGs are meant to compete with common toxic materials such as Bi₂Te₃, PbTe and CoSb that have Seebeck coefficients in the range of ~ 290-700 μV/K, similar to that of the produced Mg₂Si powders and lower than that of 3D printed bulk Mg₂Si pieces, measured to be ~ 4866 μV/K. Also, their measured thermal conductivities proved to be significantly lower (~ 0.2 W/mK) than that reported for Mg₂Si (≥ 4 W/mK). However, it is herein demonstrated that such thermoelectric properties are not stable over time. Pressureless sintering proved to be indispensable, but difficultly achievable by long thermal annealing (even above 32 h) in inert atmosphere at 400 °C, at least for bulk Mg₂Si pieces constituted by a mean grain size of 2-3 μm. Hence, for overcoming this sintering challenge and become the silicide's extrusion viable in the production of bulk thermoelectric parts, alternative pressureless sintering methods will have to be further explored.

P1827Maximum systolic flow deceleration rate in the false lumen by 4D-flow MRI is associated with aortic dilatation in patients with chronic descending aorta dissection

Introduction

Patent false lumen (FL) in aortic dissection has been associated with poor prognosis mainly due to aortic expansion. Although morphologic variables have been related to aortic dilatation as expression of high pressure in the FL, they do not reflect flow characteristics. We propose the maximum systolic flow deceleration rate (MSDR) in the FL, quantified by 4Dflow, assuming that flow should be strongly decelerated during systole under high pressure.

Methods

Twenty-nine patients with a patent FL after aortic dissection (no Marfan syndrome) and with a follow-up of at least 3 years underwent a contrast-enhanced 4D-flow MR. FL acceleration was calculated during the cardiac cycle in a sub-volume of the descending aorta (5 cm around the level of the pulmonary bifurcation). MSDR was determined as the maximum minus the minimum acceleration in systole over the corresponding time interval (Figure 1a). Aortic growth rate (GR) was defined as the difference between final and initial aortic diameters obtained by angio-CT over the period of follow-up. Population was divided into tertiles based on GR.

Results

Demographic, clinical variables or basal aortic diameter did not show differences among GR groups (Table 1). MSDR was statistically different in patients with a GR <1mm/year (group 1) compared to fast-dilating patients (groups 2, 3) (Figure 1c). MSDR showed a positive linear correlation with GR resulting in a Pearson's correlation of 0.481 (p=0.008) (Figure 1b).

Table 1. Demographic and other variables Tertile 1 Tertile 2 Tertile 3 p-value Age (year) 63.4 (±13.5) 62.5 (±13.6) 64.6 (±6.7) 0.902 BSA (m2) 2.0 (±0.2) 1.8 (±0.2) 1.9 (±0.1) 0.213 Men 6 (86%) 4 (57%) 4 (100%) 0.210 Hypertension 4 (66%) 5 (71%) 4 (100%) 0.438 Atherosclerosis 1 (17%) 1 (14%) 0 (0%) 0.699 Initial diameter 45.0 (±7.69) 36.0 (±4.2) 37.0 (±6.5) 0.078 Final diameter 49.5 (±6.74) 44.9 (±5.7) 59.2 (±9.8) 0.049* Follow-up (year) 11.8 (±8.79) 7.9 (±3.3) 8.1 (±4.0) 0.921 Aortic GR (mm/year) 0.3 (±0.3) 1.2 (±0.3) 2.6 (±1.0) 0.001* MSDR (cm/s3) 1212 (±468) 2411 (±1034) 2558 (±1098) 0.005* Values are mean (±SD) or n (%).

Conclusion

MSDR of flow in the FL derived from 4D-flow RM is related to GR of dissected descending aorta. It is useful to discriminate mild vs. significant aorta enlargement and identify patients who may benefit from earlier therapy.

Cannabis-Associated Asthma and Allergies

Inhalation of cannabis smoke is its most common use and the pulmonary complications of its use may be the single most common form of drug-induced pulmonary disease worldwide. However, the role of cannabis consumption in asthma patients and allergic clinical situations still remains controversial. To review the evidence of asthma and allergic diseases associated with the use of marijuana, we conducted a search of English, Spanish, and Portuguese medical using the search terms asthma, allergy, marijuana, marihuana, and cannabis. Entries made between January 1970 and March 2017 were retrieved. Several papers have shown the relationship between marijuana use and increase in asthma and other allergic diseases symptoms, as well as the increased frequency of medical visits. This narrative review emphasizes the importance to consider cannabis as a precipitating factor for acute asthma and allergic attacks in clinical practice. Although smoking of marijuana may cause respiratory symptoms, there is a need for more studies to elucidate many aspects in allergic asthma patients, especially considering the long-term use of the drug. These patients should avoid using marijuana and be oriented about individual health risks, possible dangers of second-hand smoke exposure, underage use, safe storage, and the over smoking of marijuana.

Highly transparent copper iodide thin film thermoelectric generator on a flexible substrate

Simultaneously transparent and flexible conductive materials are in demand to follow the current trend in flexible technology. The search for materials with compliant optoelectronic properties, while simultaneously retaining their electric conductivity at high strain deformation, comprises promising opportunities in modern nanotechnology. Copper iodide (CuI) is not only the most transparent and highly conductive p-type material, but its optimization has contributed to improved ZT values in planar thin-film thermoelectrics. In this work, the readiness of CuI thin films to transparent, flexible technology is evidenced. A maximum ZT value of 0.29 for single CuI thin films of ca. 300 nm in thickness is reported. Values of open-circuit voltage V_oc, short circuit current I_sc and power output of p–n thermoelectric modules of Gallium-doped zinc oxide (GZO) and CuI thin films deposited on a transparent flexible Kapton® (type CS) substrate are reported, and a prototype of a flexible transparent thermoelectric generator based on 17 p–n modules was constructed. Bending analysis of CuI thin films reveals interesting, distinct results when submitted to compression and tension analysis – a behaviour not seen in conventional semiconducting thin films under equivalent strain conditions. A plausible account for such diversity is also included.

Simultaneously transparent and flexible conductive materials are in demand to follow the current trend in flexible technology. A highly transparent and flexible thermoelectric generator of 17 p–n modules was constructed based on copper iodide thin films.