Asymptomatic giant ascending aortic aneurysm: a challenging surgical strategy for a silent bicuspid aortopathy.

We report the case of an incidental finding of a huge aneurysm of the ascending aorta with a congenital bicuspid aortic valve type 0-lateral. This severe condition was totally unknown to the patient, who was asymptomatic for cardiovascular disease. The aneurysmal mass involved the entire mediastinum, altering the normal anatomical relations, so the operative strategy was modified intraoperatively, tailoring the surgical technique to the anatomical conditions found. Despite a delayed awakening, the patient had an uncomplicated postoperative course. Therefore, this case highlights the importance of not underestimating nonspecific, seemingly harmless symptoms and signs that may reveal potentially catastrophic pathologies, while also focusing on the surgical technique used. The modified Cabrol procedure, while an underutilized technique, if present in the cardiac surgeon's "arsenal," can represent a life-saving strategy in complex cases requiring an aortic valve and ascending aorta replacement.

Echocardiographic scores for biventricular repair risk prediction of congenital heart disease with borderline left ventricle: a review.

The aim of this review is to highlight the strengths and limitations of major echocardiographic biventricular repair (BVR) prediction models for borderline left ventricle (LV) in complex congenital heart disease (CHD). A systematic search in the National Library of Medicine for Medical Subject Headings and free text terms including echocardiography, CHD, and scores, was performed. The search was refined by adding keywords for critical aortic stenosis (AS), borderline LV, complex left ventricular outflow tract (LVOT) obstruction, hypoplastic left heart syndrome/complex (HLHS/HLHC), and unbalanced atrio-ventricular septal defects (uAVSD). Fifteen studies were selected for the final analysis. We outlined what echocardiographic scores for different types of complex CHD with diminutive LV are available. Scores for CHD with LVOT obstruction including critical AS, HLHS/HLHC, and aortic arch hypoplasia have been validated and implemented by several studies. Scores for uAVSD with right ventricle (RV) dominance have also been established and implemented, the first being the atrioventricular valve index (AVVI). In addition to AVII, both LV/RV inflow angle and LV inflow index have all been validated for the prediction of BVR. We conclude with a discussion of limitations in the development and validation of each of these scores, including retrospective design during score development, heterogeneity in echocardiographic parameters evaluated, variability in the definition of outcomes, differences in adopted surgical and Interventional strategies, and institutional differences. Furthermore, scores developed in the past two decades may have little clinical relevance now. In summary, we provide a review of echocardiographic scores for BVR in complex CHD with a diminutive LV that may serve as a guide for use in modern clinical practice.

Endovascular Surgery of Descending Thoracic Aorta Involved in T4 Lung Tumor.

PURPOSE: Surgical treatment of primary lung T4 tumors is controversial especially when the cancer invades the mediastinal structures or the descending thoracic aorta. Conventional surgical treatment is associated with a high perioperative mortality and morbidity rate. Thoracic EndoVascular Aortic Repair has emerged as a valid off-label alternative to conventional surgery. We aimed to assess perioperative and midterm aortic-related outcome of patients who have undergone aortic stent-graft implantation, followed by en bloc surgical treatment of the involved aorta and lung cancer resection. MATERIALS AND METHODS: From July 2017 to May 2020, we treated 5 patients diagnosed with a T4 lung cancer by the involvement of the descending thoracic aorta. When only the descending thoracic aorta is involved, a 2-stage procedure was considered, with aortic stent-graft implantation performed before tumor resection. One-stage strategy, with stent-graft implantation carried out before thoracotomy, was preferred for patients with the involvement of cardiac and/or other vascular mediastinal structures. RESULTS: The mean age was 58.4 ± 6.2 years. All patients were affected by non-small cell lung cancer. All 5 patients required a single stent-graft to completely cover the involved segment of aorta. Four patients underwent a 2-stage procedure. One patient, with the involvement of the left inferior pulmonary vein, required a 1-stage en bloc resection of the left lower lobe, aortic wall adventitia, left inferior pulmonary vein, and reconstruction of the left atrial wall. Primary procedural success was achieved in all. At follow-up, no patient developed aortic-related complications. One patient died 2 years after surgery, due to local recurrence of the tumor. CONCLUSION: T4 lung resection combined with aortic stent-graft implantation can be safely performed. Endovascular surgery, by avoiding the use of cardiopulmonary bypass, aortic cross-clamping, and graft replacement, can reduce significant morbidity and mortality rate. Postoperative and long-term outcome of these patients treated with endovascular surgery is mainly related to pulmonary disease, not to aortic treatment.

Cardiac Troponin-T Release After Sport and Differences by Age, Sex, Training Type, Volume, and Intensity: A Critical Review.

BACKGROUND: Postexercise release of cardiac troponin (cTn) is a well-known phenomenon, although the influence of various confounders remains unclear. The aim of this critical review was to analyze the postexercise release of cTn according to age, sex, different types of sport, exercise intensity and duration, and training level. DATA SOURCES: A literature search was performed within the National Library of Medicine using the following keywords: cTn, peak, release, and exercise. The search was further refined by adding the keywords athletes, children/adolescents, and sport. MAIN RESULTS: For final analysis, 52 studies were included: 43 adult studies, 4 pediatric studies, and 5 with a mixed population of adults and children. Several studies have investigated the kinetics of cTn response after exercise with different biomarkers. The current evidence suggests that sport intensity and duration have significant effects on postexercise cTn elevation, whereas the influence of the type of sport, age, and sex have been not completely defined yet. Most data were obtained during endurance races, whereas evidence is limited (or almost absent), particularly for mixed sports. Data on young adults and professional athletes are limited. Finally, studies on women are extremely limited, and those for non-White are absent. CONCLUSIONS: Postexercise release of cTn can be observed both in young and master athletes and usually represents a physiological phenomenon; however, more rarely, it may unmask a subclinical cardiac disease. The influence of different confounders (age, sex, sport type/intensity/duration, and training level) should be better clarified to establish individualized ranges of normality for postexercise cTn elevation.

A statistical comparison of reproducibility in current pediatric two-dimensional echocardiographic nomograms.

BACKGROUND: The aim of this study is to compare new pediatric nomograms for clinical parameters from 2D echocardiography. METHODS: 2D pediatric echocardiographic parameters from four recent nomograms were used for statistical analysis. To assess the accuracy of the predictive models from each study, namely multivariate, linear, and nonlinear regression, mean values and 5th and 95th percentiles (µ ± 1.65σ) were calculated. A Z-score calculator was created. RESULTS: Mean values and 5th and 95th percentiles have been provided for a range of BSA (0.15-2.20 m2) for each nomogram assessed in this study. Moreover, plots of Z-scores over the same range of BSA have been generated to assess trends among different studies. For most measurements from the two most recent nomograms, namely Lopez et al. and Cantinotti et al., differences were within a Z-score of 0.5 (Z-score range: 0.001-1.26). Measurements from Sluysmans and Colan and Pettersen et al. were observed to diverge from Lopez et al. at the upper extremities of BSA. Differences among various nomograms emerged at lower extremes of BSA. CONCLUSIONS: The two most recent echocardiographic nomograms were observed to have the most statistically similar ranges of normality. Significant deviations in ranges of normality were observed at extremes of BSA. IMPACT: Echocardiographic nomograms for pediatric age are discordant. Comparison of current pediatric echocardiographic nomograms. A Z-score calculator was created. Clinical relevance of differences among nomograms is highlighted.

Intracardiac flow visualization using high-frame rate blood speckle tracking echocardiography: Illustrations from infants with congenital heart disease.

We report applications of novel high-frame rate blood speckle tracking (BST) echocardiography in a series of infants with congenital heart disease (CHD). BST echocardiography was highly feasible, reproducible, and fast. High-frame rate BST provided complimentary information to conventional color-Doppler data enhancing the visualization and understanding of anomalous blood trajectories (eg, shunt direction, regurgitant volumes, and stenotic jets) and vortex formation. High-frame rate BST echocardiography is a new, promising imaging tool that may be helpful for deeper understanding of complex CHD physiology.

Pediatric ranges of normality for 2D speckle-tracking echocardiography atrial strain: differences between p- and r-gating and among new (Atrial Designed) and conventional (Ventricular Specific) software's.

BACKGROUND: 2D speckle tracking echocardiography (STE) atrial strain (ε) analysis in children is gaining interest; however, pediatric nomograms remain limited. Comparison among conventional software's (designed for left ventricle and adapted to atria and using R-gating analysis) and new software's (designed for atria and allowing for both R- and P-gating) are lacking. The present study aims to establish pediatric nomograms for atrial ε using an atrial dedicated software and to compare values obtained by (a) R- and P-gating and, (b) R-gating with new and conventional software. METHODS: Echocardiographic measurements included STE left (LA) and right (RA) atrial longitudinal reservoir, conduit and contractile ε. Age/weigh/height/heart rate, and body surface area (BSA) were used as independent variables in the statistical analysis. RESULTS: In all, 580 healthy subjects (age range, 31 days-18 years; mean age 7.5 years; median age 7.1 years; inter-quartile range, 4.3-10.7 months; 45.5% female) were included. Feasibility of atrial ε measurements was high (98.9-96.8%). At lower age, atrial conduit ε was lower (p<0.001) while contractile ε was higher (p<0.001). All atrial ε values calculated with P-gating method were lower-than R-gating values (p<0.001). R-gated LA ε reservoir values generated with the new software were lower, and R-gated RA contractile ε higher than with the conventional software (p<0.011). CONCLUSION: We report pediatric atrial ε values from a dedicated atrial software. Maturational changes in STE atrial ε values were demonstrated. Significant differences were observed among ε values obtained with P- and R-gating and with different software's.

Status of coronary disease and results from early endovascular aneurysm repair after preventive percutaneous coronary revascularization.

BACKGROUND: The incidence of coronary artery disease (CAD) is high in patients with an aortic aneurysm but preoperative routine coronary angiography and preventive coronary revascularization are not recommended to reduce cardiac events in patients with severe CAD. AIM: This study evaluated the safeness and efficacy of preventive percutaneous coronary intervention (PCI) in patients with severe CAD scheduled for endovascular aneurysm repair (EVAR). METHODS: All patients with descending thoracic aneurysm (DTA) or abdominal aortic aneurysm (AAA) scheduled for EVAR underwent preliminary coronary angiography. Based on coronary angiography results, 917 patients (40.7%) had significant CAD and were treated by percutaneous coronary intervention (PCI; CAD group) and 1337 patients (59.3%) were without or with mild/moderate CAD and were considered as controls (no-CAD group). To evaluate the safeness and efficacy of preventive PCI in patients with severe CAD undergoing EVAR, groups were compared for hospital and 12-month cardiac adverse events. RESULTS: CAD was present in 1210 patients (53.6%): significant in 917 patients (38%) and mild to moderate in 293 patients (5.3%). Hospital and 12-month cardiac events occurred in 15 (1.6%) and 13 (1.4%) CAD group patients and in 9 (0.7%) and 8 (0.4%) no-CAD group patients (p = .05 and p = .08), respectively. Hospital and 12-month cardiac deaths occurred in 3 (0.3%) and 2 (0.2%) CAD group patients and in 3 (0.2%) and 2 (0.2%) no-CAD group patients (p = .9 and p = .9), respectively. CONCLUSION: The strategy to treat severe CAD preoperatively by PCI and early subsequent EVAR brings a similar outcome to that in patients without or with mild/moderate CAD.

Causal Loop Diagrams for supporting Nature Based Solutions participatory design and performance assessment.

The contribution of Nature Based Solutions (NBSs) for supporting climate change adaptation and water-related risks reduction is becoming increasingly relevant for policy and decision-makers, compared to 'grey infrastructures', thanks to their capability to jointly deal with a multiplicity of societal and environmental challenges, producing several co-benefits besides limiting the impacts of water-related risks. Nevertheless, their mainstreaming is still limited by several barriers, which are often related to socio-institutional (e.g. limited cooperation and stakeholders' involvement, limited awareness about NBSs impacts) rather than to technical aspects. In this context, innovative tools for NBSs planning, design, implementation and assessment are required, along with effective processes capable of supporting stakeholders' participation. The present research aims to propose a shift in the approach to NBSs design, based on the early stakeholders' involvement in the identification, modelling and performance assessment in terms of benefits and, particularly, co-benefits production. A multi-step methodology was implemented for the purpose, combining both individual and participatory activities. Reference is made to one of the case studies of the NAIAD project, namely the Balta Potelu Pond Area (Lower Danube, Romania). Causal Loop Diagrams (CLDs) were used to describe the system in terms of causal connections and mutual influences, incorporating stakeholders' views and ideas. Inputs from both institutional (e.g. ministries and municipalities) and non-institutional stakeholders (e.g. NGOs and members of the local communities) were integrated. This allowed a comparative assessment of multiple NBSs, based on the analysis of benefits and co-benefits produced, as well as the identification of trade-offs among different stakeholders (e.g. the increase of agricultural production versus biodiversity conservation) and potential side effects. CLDs were then coupled with a Performance Matrix (a basic feature of Multi-Criteria Decision Analysis) and fuzzy logic to help decision-makers identify the most suitable NBSs for the area. The whole process was aimed at facilitating the process of NBSs selection and analysis, while considering the multiple impacts associated with their implementation.

"The heart supporters": systematic review for ventricle assist devices in congenital heart surgery.

Ventricular assist device (VAD) implantation is a widely used procedure in children with cardiac failure refractory to medical therapy as a long-term bridge to recovery or transplant. This strategy has proved to be of an enormous advantage in the cure of these children. The aim of this review is to evaluate the current strategies used for clinical monitoring of paediatric patients with a VAD, focusing on the management of several aspects such as anticoagulant and antiplatelet therapy, haemorrhagic and thrombotic complications, as well as the effects that VADs have on the exposure, effectiveness and the safety of drugs. The sources used for this research are MEDLINE, PubMed and Cochrane Library. The use of key words such as "paediatric ventricular assist device", "clinical management", "anticoagulant therapy" and "infections" retrieved 146 papers. With the application of the inclusion criteria, 42 articles have been selected, but following further analysis, only 21 were eligible. The post-implant process is still complicated due to the lack of guidelines regarding clinical management and for the frequent occurrence of adverse events including bleeding, infection and thromboembolic episodes. From these findings, we can highlight the importance of establishing a suitable antithrombotic therapy, as well as ensuring that the prevention and treatment of infection are paramount during the management of these patients. The clinical management of VAD paediatric children is complex and challenging. At the moment, there are no guidelines regarding strategies to adopt, but from the analysed surveys, it has been possible to highlight a relative coherence between adopted therapies in different centres worldwide.

Pediatric nomograms for left ventricle biplane 2D volumes in healthy Caucasian children.

BACKGROUND: Left ventricular (LV) volumes are basic parameters used to estimate ventricular size and function; however, normal values are not available in children. The aim of our study is to provide normal values for LV volumes (measured with the biplane Simpson method) in healthy children. MATERIALS AND METHODS: We prospectively studied 1320 healthy Caucasian Italian children (age 0 days-17 years, 49.4% female). Echocardiographic measurements on LV volumes were performed. Age, heart rate (HR), and body surface area (BSA) were used as independent variables in different analyses to predict the mean values of each measurement. RESULTS: Models with exponential (ln[y] = a + b*ln[x]) equations resulted in the best fit for LV volumes. The association with BSA was found to be stronger than the association of HR and age. Thus BSA was used for normalization of our data. Predicted values and Z-score boundaries by BSA are provided. CONCLUSIONS: We report normal values for 2D biplane LV volumes in a population of healthy children. These data cover a gap in current pediatric echocardiographic nomograms and may serve as baseline for evaluation of children with cardiac defects characterized by LV dilatation or hypoplasia.

Retrosternal Clots After Fontan Surgery by Systematic Evaluation With Transthoracic Ultrasound.

OBJECTIVES: Bleeding is a common, serious, and often subtle complication after total cavopulmonary connection surgery. The aim of the present study was to assess the incidence of retrosternal clots after surgery, which were searched for systematically with transthoracic ultrasound. DESIGN: Retrospective study. SETTING: Single center. PARTICIPANTS: Total cavopulmonary surgeries were reviewed from January 2016 to May 2019. INTERVENTIONS: Thoracic ultrasound with careful evaluation of the retrosternal area was performed at different postoperative times (12-36 hours, 5-7 days, and before discharge) as completion of routine echocardiography. MEASUREMENTS AND MAIN RESULTS: Among 37 children undergoing total cavopulmonary connection (mean age 5.5 ± 1.8 years [range 2.4-11.7]; mean body surface area 0.7 ± 0.1 m2 [range 0.3-1.6 m2]), retrosternal clots were detected in 18 (48.6%). Of these, 7 (13.5%) had small clots (<1 cm), 2 (5.4%) small to moderate sized clots (>1 cm-<2 cm), 3 (8.1%) moderate sized clots (>2-<3 cm), and 6 (16.2%) large clots (>3 cm). Four of the 6 detected large clots required surgical revision, and in the other 2 patients, the clots were not treated because the patients' conditions were clinically stable. When 3 major groups (group 1-no or small clots, group gropu 2 are small to moderate or moderate, group 3-large clots) were evaluated, no significant differences were noted in age, body surface area, CPB time, conduit type, or the number of previous surgeries. CONCLUSIONS: With thoracic ultrasound diagnosis, existence of retrosternal clots was found to be very common after total cavopulmonary connection. Most clots were small or moderate with no clinical effect; however, large clots that required redo surgery also were detected.

Echocardiographic examination of mitral valve abnormalities in the paediatric population: current practices.

We reviewed the recent literature for echocardiographic assessment of mitral valve abnormalities in children. A literature search was performed within the National Library of Medicine using the keywords "mitral regurgitation and/or stenosis, children." The search was refined by adding the keywords "echocardiographic definition, classification, and evaluation." Thirty-one studies were finally included. Significant advances in echocardiographic imaging of mitral valve defects, mainly due to the implementation of three-dimensional technology, contribute to a better understanding of the underlying anatomy. However, heterogeneity between classification systems of mitral valve disease severity is a serious problem. For regurgitant lesions, there is only very limited evidence from small studies that support the adoption of quantitative/semi-quantitative indexes commonly employed in adults. Despite the lack of evidence base, qualitative evaluation of regurgitation severity is often employed. For stenotic lesions, no clear categorisation based on trans-valvular echocardiography-derived "gradients" has been consistently applied to define mild, moderate, or severe obstruction across different paediatric age ranges. Quantitative parameters such as valve area have also been poorly validated in children. Adult recommendations are frequently applied without validation for the paediatric age. In conclusion, significant advances in the anatomical evaluation of mitral valve diseases have been made, thanks to three-dimensional echocardiography; however, limitations remain in the quantitative/semi-quantitative estimation of disease severity, both with respect to valvular regurgitation and stenosis. Because adult echocardiographic recommendations should not be simply translated to the paediatric age, more specific paediatric guidelines and standards for the assessment of mitral valve diseases are needed.

Nomograms for Cardiovascular Magnetic Resonance Measurements in the Pediatric Age Group: To Define the Normal and the Expected Abnormal Values in Corrected/Palliated Congenital Heart Disease: A Systematic Review.

Our purpose is to provide an overview and to systematically review the strengths and limitations of studies on pediatric and adolescent normal values for cardiovascular MRI parameters. A literature search was performed within the National Library of Medicine using the following keywords: normal, reference values, cardiovascular magnetic resonance imaging, and children/pediatric. Eleven published studies evaluating cardiovascular MRI measurements in normal children were included in the present analysis. Our results revealed reasonable consistencies in the protocols employed for cardiovascular MRI. Inter- and intraobserver variability analyses were performed in most studies and generally showed acceptable reproducibility. However, several numerical and methodological limitations emerged. Besides small sample sizes (the largest study enrolled 114 subjects), data for some structures (pulmonary arteries, aortic arch) were limited, and neonates/infants were poorly represented (eg, only two studies). There was heterogeneity regarding measurement normalization (eg, for gender, age, or both), and data were mostly expressed as mean values, while z-scores (commonly used in pediatric echocardiography) were rarely employed. Theoretically, a z-score or a standard deviation of ±2 is considered pathological. Furthermore, differences among races and ethnic groups were not evaluated. In conclusion, our analyses revealed an important need for generation of pediatric and adolescent cardiovascular MRI nomograms built over a wide population of healthy children, using consistent methodologies and with consideration of potentially relevant confounders. More data on expected abnormal values in specific CHD populations (eg, univentricular hearts) also need to be defined. Level of Evidence: 2 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;49:1222-1235.

Double Orifice Mitral Valve in Tricuspid Atresia: A Rare Association.

We here report a neonate with prenatal echocardiographic diagnosis of tricuspid atresia, with normally related great vessels, and large ventricular septal defect. This diagnosis could be confirmed with echocardiography at birth. An additional double mitral orifice was also seen. This is a very rare association.

Use of linear and convex ultrasound transducers for evaluation of retrosternal area in patients after cardiac surgery.

The use of linear and convex transducers is usually reserved for ultrasound imaging of vessels, abdominal organs, and lungs. However, the use of these transducers may be extended for the evaluation of thoracic structures. We describe our experience with the use of linear and convex transducers in the evaluation of the retrosternal area, which is usually difficult to visualize by conventional echocardiography and so could provide improved diagnostic information in patients after cardiac surgery.

Lung ultrasound reclassification of chest X-ray data after pediatric cardiac surgery.

INTRODUCTION: Lung ultrasound is gaining consensus for the diagnosis of some pulmonary conditions. Pulmonary complications are common in pediatric cardiac surgery. However, its use remains limited in this setting. Our aim was to test the feasibility of lung ultrasound following pediatric cardiac surgery and to compare lung ultrasound and chest X-ray findings, assessing whether lung ultrasound may provide additional information. METHODS: One hundred and thirty-eight lung ultrasound examinations were performed in 79 children (median age 9.3 months) at different time points after surgery. For each hemithorax, 3 areas (anterior/lateral/posterior) have been evaluated in the upper and lower halves of the chest (for a total of 6 scanning sites per side). Pleural effusion, atelectasis, and the number of B-lines were investigated. RESULTS: Lung ultrasound was feasible in all cases in at least 1 of the 3 areas. Feasibility was different for the lateral, posterior, and anterior areas (100%, 90%, and 78%, respectively). The posterior areas were more sensitive than anterior and lateral ones in the diagnosis of effusion/atelectasis. In 81 cases, lung ultrasound allowed reclassification of chest X-ray findings, including 40 new diagnoses (diagnosis of effusion/atelectasis with negative chest X-ray reports) and 41 changes in diagnosis (effusions reclassified as atelectasis/severe congestion or vice versa). Although new diagnosis of small-to-moderate effusion/atelectasis was of limited clinical value, in 29 cases the new diagnosis changed the therapeutic approach. CONCLUSION: Lung ultrasound is feasible and accurate for the diagnosis of common pulmonary conditions after pediatric cardiac surgery, allowing reclassification of chest X-ray findings in a significant number of patients.

Strengths, Limitations, and Geographical Discrepancies in the Eligibility Criteria for Sport Participation in Young Patients With Congenital Heart Disease.

OBJECTIVE: Benefits of physical activity has been shown in children with congenital heart disease (CHD). In several forms of CHD, the risk of sudden death remains a major concern both for parents and clinicians, who in turn will have to consider the risk-benefit ratio of sport participation versus restriction. DATA SOURCE: A literature search was performed within the National Library of Medicine using the keywords: Sport, CHD, and Eligibility. The search was further refined by adding the keywords: Children, Adult, and Criteria. MAIN RESULTS: Fifteen published studies evaluating sport eligibility criteria in CHD were included. Seven documents from various scientific societies have been published in the past decade but which of them should be adopted remains unclear. Our research highlighted accuracy and consistency of the latest documents; however, differences have emerged between the US and European recommendations. Eligibility criteria were consistent between countries for simple congenital heart defects, whereas there are discrepancies for borderline conditions including moderate valvular lesions and mild or moderate residual defects after CHD repair. Furthermore, some of the more severe defects were not evaluated. Multiple recommendations have been made for the same CHD, and cut-off values used to define disease severity have varied. Published eligibility criteria have mainly focused on competitive sports. Little attention was paid to recreational activities, and the psychosocial consequences of activity restriction were seldom evaluated. CONCLUSIONS: Comprehensive consensus recommendations for sport eligibility evaluating all CHD types and stages of repair are needed. These should include competitive and recreational activities, use standardized classifications to grade disease severity, and address the consequences of restriction.

A system dynamics model for supporting decision-makers in irrigation water management.

Water management is a controversial environmental policy issue, due to the heterogeneity of interests associated with a shared resource and the increasing level of conflict among water uses and users. Nowadays, there is a cumulative interest in enhancing multi-stakeholder decision-making processes, overtaking binding mercantile business, in water management domain. This requires the development of dynamic decision-aiding tools able to integrate the different problem frames held by the decision makers, to clarify the differences, to support the creation of collaborative decision-making processes and to provide shared platforms of interactions. In literature, these issues are faced by concepts such as Ostrom's action arena and Ostanello-Tsoukiàs' interaction space (IS). The analysis of the interactions structure and of the different problem framing involved are fundamental premises for a successful debate for the management of a common-pool resource. Specifically, the present paper suggests a dynamic evolution of the IS, highlighting its criticalities. It develops an alternative perspective on the problem, using a System Dynamics Model (SDM), exploring how different actions can influence the decision-making processes of various stakeholders involved in the IS. The SDM has been implemented in a multi-stakeholders decision-making situation in order to support water management and groundwater protection in the agricultural systems in the Capitanata area (Apulia region, Southern Italy).

Natural Assurance Scheme: A level playing field framework for Green-Grey infrastructure development.

This paper proposes a conceptual framework to systematize the use of Nature-based solutions (NBS) by integrating their resilience potential into Natural Assurance Scheme (NAS), focusing on insurance value as corner stone for both awareness-raising and valuation. As such one of its core goal is to align research and pilot projects with infrastructure development constraints and priorities. Under NAS, the integrated contribution of natural infrastructure to Disaster Risk Reduction is valued in the context of an identified growing need for climate robust infrastructure. The potential of NAS benefits and trade-off are explored by through the alternative lens of Disaster Resilience Enhancement (DRE). Such a system requires a joint effort of specific knowledge transfer from research groups and stakeholders to potential future NAS developers and investors. We therefore match the knowledge gaps with operational stages of the development of NAS from a project designer perspective. We start by highlighting the key role of the insurance industry in incentivizing and assessing disaster and slow onset resilience enhancement strategies. In parallel we place the public sector as potential kick-starters in DRE initiatives through the existing initiatives and constraints of infrastructure procurement. Under this perspective the paper explores the required alignment of Integrated Water resources planning and Public investment systems. Ultimately this will provide the possibility for both planners and investors to design no regret NBS and mixed Grey-Green infrastructures systems. As resources and constraints are widely different between infrastructure development contexts, the framework does not provide explicit methodological choices but presents current limits of knowledge and know-how. In conclusion the paper underlines the potential of NAS to ease the infrastructure gap in water globally by stressing the advantages of investment in the protection, enhancement and restoration of natural capital as an effective climate change adaptation investment.