The cavum septi pellucidi (CSP) is a fluid-filled cavity box situated on the midline between the medial walls of the two lateral ventricles and placed above the fornix and below the corpus callosum. The formation of the CSP begins at 14 weeks and is completed around 17 weeks.

A regular CSP indirectly indicates the correct development of the corpus callosum and the midline of the fetal brain. Therefore, its evaluation is mandatory during routine obstetric scans. The available guidelines do not report specific recommendations on the morphology or biometry of the fetal CSP, thus leaving to the experience of the operator and, thus, to a subjective evaluation, the identification of potential anomalies.

Our aim is to construct methodologically robust reference charts for the CSP’s width, length and length-to-width ratio in relation to gestational age and fetal biparietal diameter.

The REC-FAST study (Reference Charts for the Fetal cAvum SepTi pellucidi) is a prospective monocentric cross-sectional study on consecutively enrolled pregnant women accessing our Obstetric Unit at the Foundation IRCCS San Gerardo dei Tintori, Monza, Italy, for fetal ultrasound evaluation.

Women will be eligible if carrying an uncomplicated singleton pregnancy between 19^0/7 and 36^6/7 weeks’ gestation with a certain pregnancy dating by first trimester ultrasound with crown-rump length measurement, and if aged between 18 and 45 years.

After signing the informed consent, the ultrasound scan will be performed and the CSP’s width and length will be measured by means of the inner-to-inner technique and its morphology recorded.

In order to achieve the statistical power required for properly constructing reference charts, we will divide our population into six groups according to the gestational age when the ultrasound scan will be performed (each group will cover a 3-week interval starting at 19^0/7 until 36^6/7 weeks). A minimum sample size of 80 will be reached for each gestational age group. Before charting, the data will be checked for consistency to identify any outliers. Where possible, outliers will be corrected by comparing with the original values (computation errors); otherwise, such data will be excluded. The fetal charts will be traced using the Cole and Green-Lambda, Median, and Sigmamethod (CG-LMS); in addition, the use of alternative modelling approaches, such as parametric models derived from the Extended Mechanistic Growth Function method, will be explored.

Ethical approval for this study was obtained by the Lombardy Ethics Committee n.3 (15 December 2023) prior to the commencement of the research. Written informed consent will be obtained from all participants. Women will be free to decline participation or to withdraw at any time.

Findings will be presented at scientific meetings and published in peer-reviewed scientific journals in the field of obstetrics and fetal medicine. Also, they will be disseminated to study participants through dedicated online and in-person meetings and to the public through reach-out activities involving families and healthcare specialists.

Aortic valve stenosis (AVS) represents the most prevalent primary valvular lesion necessitating surgical intervention or transcatheter intervention in Europe and North America. Its prevalence is increasing at a rapid rate as a consequence of the ageing population. A variety of mechanical interventions are available to determine the management of AVS; however, there is currently a paucity of robust data with which to perform a comparative analysis of the efficacy of surgical aortic valve replacement (SAVR) and that of conventional stented xenograft bioprostheses (BP) or sutureless aortic valves (SAV) and transcatheter aortic valve implantation (TAVI). The present study aims to compare the effectiveness and clinical outcomes of SAVR using BP or SAV technique and TAVI in patients with severe AVS.

A collaboration between three cardiac surgery centres across two European countries has resulted in the conception of the Transcatheter Aortic Valve Implantation vs Surgical Aortic Valve Replacement trial. This prospective non-randomised trial is designed to evaluate the long-term outcomes of TAVI in comparison to SAVR for AVS in patients at risk of severe valve obstruction. The registry will enrol successive patients who have undergone mechanical intervention for AVS between January 2015 and December 2025. Investigators will assess the difference between replacement procedures for both the standard surgical approach and the transcatheter procedure. The principal clinical outcome under consideration will be the composite degree of all-cause mortality, ischaemic stroke or rehospitalisation at 10 years. The present study will also have a number of secondary endpoints, including all-cause mortality, followed by functional status, hospitalisation, neurocognition, physiological measures (echocardiographic assessment), adverse events and reoperation.

It is hypothesised that the nature of the trials will serve to minimise bias related to institutional volume and surgical experience. Each participating centre is required to have an aortic valve programme that enables proper follow-up and management of any late aortic events following replacement surgery for the AVS. The data collected will provide valuable insight into the comparative effectiveness of various surgical approaches, both standardised and advanced, in aortic valve surgery and TAVI. This comprehensive analysis will contribute significantly to the development of robust international guidelines.

Clinical Trial Gov.Com. ID: NCT05261204 IRB. ID: 2022011057