Clinical Research Directory

Sleep-disordered Breathing in Infants With Myelomeningocele

This study aims to determine whether the risk for sleep-disordered breathing in infants with myelomeningocele (a severe form of spina bifida) differs among those who underwent fetal vs. postnatal surgery, and to examine the link between sleep-disordered breathing and neurodevelopment.

Evolution of Hypoxic Burden and Sympathetic/Parasympathetic Balance in Patients With Pulmonary Hypertension

Background and Rationale: Sleep-disordered breathing and nocturnal hypoxemia are highly prevalent in patients with precapillary pulmonary hypertension (PH), and current guidelines recommend systematic sleep assessment in this population. In obstructive sleep apnea, nocturnal hypoxic burden-defined as the area under the SpO₂ desaturation curve associated with respiratory events (%.min/h)-has demonstrated strong prognostic value for cardiovascular morbidity and mortality. However, its role in precapillary PH has not yet been investigated. Evaluating hypoxic burden in this population may refine indications and therapeutic targets for nocturnal oxygen therapy. In addition, pulmonary hypertension is characterized by autonomic nervous system (ANS) dysfunction, including increased sympathetic tone, reduced heart rate variability (HRV), and a higher incidence of cardiac arrhythmias, all associated with worse prognosis. The reduction in HRV is particularly deleterious when occurring during restorative slow-wave sleep (N3), a phase marked by predominant parasympathetic activity essential for cardiovascular recovery and homeostasis. A better understanding of the interaction between nocturnal hypoxemia and ANS modulation may provide new prognostic markers and potential therapeutic targets in PH. Objectives: 1. To describe the evolution of nocturnal hypoxic burden over time in patients with precapillary pulmonary hypertension (at baseline, 12 months, and 24 months). 2. To describe the longitudinal evolution of HRV parameters (RMSSD, LF/HF ratio, HF) at baseline, 12 months, and 24 months. 3. To evaluate cross-sectional correlations (at baseline, M12, and M24) between HRV parameters, hypoxic burden, oxygen desaturation, apnea-hypopnea index (AHI), and clinical status. 4. To evaluate longitudinal correlations between changes in HRV parameters, hypoxic burden, desaturation, AHI, and clinical status between baseline and M12, and between baseline and M24. 5. To assess the 2-year prognostic value of HRV parameters and hypoxic burden for adverse clinical outcomes. Study Design and Population: This is a prospective, single-center observational cohort study conducted at the Pulmonary Hypertension Referral Center of Rouen University Hospital. The cohort design allows longitudinal assessment of HRV, hypoxic burden, and clinical status, enabling both cross-sectional and longitudinal correlation analyses, as well as prognostic evaluation. A total of 60 adult patients (≥18 years) with precapillary pulmonary hypertension confirmed by right heart catheterization and requiring pulmonary arterial vasodilator therapy will be included. Participants will undergo full overnight polysomnography (PSG) at: * Baseline (inclusion) * 12 months (M12) * 24 months (M24) For incident cases, baseline PSG will be performed prior to initiation of vasodilator therapy. All patients will continue to receive standard-of-care management according to current European guidelines for pulmonary hypertension. Descriptive analyses and cross-sectional correlations will pool repeated measures (excluding incident baseline values for generalization to prevalent cases). Intra-subject correlation will be accounted for using bootstrap methods. Longitudinal analyses will assess changes over time and prognostic associations. The prognostic value of HRV and hypoxic burden will be evaluated over a 2-year follow-up period. This study explores an original dimension of precapillary pulmonary hypertension pathophysiology by investigating the interaction between nocturnal oxygenation, autonomic dysfunction, and clinical evolution. Identification of hypoxic burden and HRV as prognostic markers may contribute to improved risk astratification and therapeutic optimization in this high-risk population.

Apnea, Stroke and Incident Cardiovascular Events

This prospective cohort study aims to compare the proportion of cardiac or cerebrovascular events after a first stroke, a first transient ischemic attack (TIA) or recurrent TIA, between sleep-disordered breathing (SDB) and non-SDB (control) patients, one year after SDB diagnosis, performed 3 months after stroke onset. The primary outcome is a composite endpoint composed of cardiac or cerebrovascular events regrouping: death from any cardiac or cerebrovascular cause, non-fatal stroke, and non-fatal acute coronary disease. 1620 patients, in the acute phase of a first stroke, TIA or recurrent TIA will be included in the cohort. Clinical, neuroimaging, sensorimotor, cognitive and biological parameters will be collected at inclusion. Three months after stroke or TIA onset, polysomnography will be performed for SDB diagnosis. Patients will be considered as having SDB for an Apnea-Hypopnea Index (AHI) \> 15 events/hour, or to the control group otherwise. The same clinical, imaging, cognitive and biological assessments than during the first visit will be performed; incident (new) cardiovascular events will be collected. Three months later, and at 1, 2, 3, 4 and 5 years after SDB diagnosis, the same clinical, cognitive, sensorimotor, and sleep-related evaluations will be performed. In addition to the aforementioned parameters, incident cardiovascular outcomes will be collected, at the same time points. The primary study outcome will be retrieved one year after stroke onset.

Sleep-disordered Breathing After Solid Organ Transplantation

Sleep-disordered breathing (SDB) describes a group of disorders in which partial or complete cessation of breathing occurs many times throughout the night, resulting in daytime sleepiness or fatigue that interferes with a person's ability to function and reduces quality of life. Transplantation has become an important treatment modality for end-stage organ failure. Transplant recipients are now living longer and, hence, develop chronic adverse medical conditions. Furthermore, transplantation is associated with weight gain. Despite the high prevalence of poor sleep and cardiovascular conditions among transplant patients, SDB is not well studied in these patients.