RESUMO
BACKGROUND: Postoperative atrial fibrillation (POAF) is a common and potentially serious complication post cardiac surgery. Hypomagnesaemia is common after cardiac surgery and recent evidence indicates that supplementation of magnesium may prevent POAF. We aim to investigate the effectiveness of continuous intravenous magnesium sulphate administration in the perioperative period to prevent POAF as compared to placebo. METHODS: The (POMPAE) trial is a phase 2, single-center, double-blinded randomized superiority clinical study. It aims to assess the impact of perioperative continuous intravenous magnesium administration on the occurrence of cardiac surgery-related POAF. A total of 530 patients will be included. Eligible patients will be randomized in 1:1 ratio to the intervention or placebo group with stratification based on the presence of valvular surgery. The objective of the infusion is to maintain ionized magnesium levels between 1.5 and 2.0 mmol/L. DISCUSSION: The primary outcome measure is the incidence of de novo POAF within the first 7 days following surgery, with censoring at hospital discharge. This trial may generate crucial evidence for the prevention of POAF and reduce clinical adverse events in patients following cardiac surgery. TRIAL REGISTRATION: The POMPAE trial was registered at ClinicalTrials.gov under the following identifier NTC05669417, https://clinicaltrials.gov/ct2/show/NCT05669417 . Registered on December 30, 2022. PROTOCOL VERSION: Version 3.3, dated 13-01-2023.
Assuntos
Fibrilação Atrial , Procedimentos Cirúrgicos Cardíacos , Sulfato de Magnésio , Humanos , Fibrilação Atrial/prevenção & controle , Fibrilação Atrial/etiologia , Fibrilação Atrial/diagnóstico , Sulfato de Magnésio/administração & dosagem , Sulfato de Magnésio/efeitos adversos , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Método Duplo-Cego , Infusões Intravenosas , Resultado do Tratamento , Complicações Pós-Operatórias/prevenção & controle , Complicações Pós-Operatórias/etiologia , Ensaios Clínicos Fase II como Assunto , Ensaios Clínicos Controlados Aleatórios como Assunto , Assistência Perioperatória/métodos , Feminino , Fatores de Tempo , Masculino , Estudos de Equivalência como Asunto , Pessoa de Meia-IdadeRESUMO
Background: Mediastinal ionizing radiotherapy is associated with an increased risk of valvular disease, which demonstrates pathological hallmarks similar to calcific aortic valve disease (CAVD). Despite advances in radiotherapy techniques, the prevalence of comorbidities such as radiation-associated valvular disease is still increasing due to improved survival of patients receiving radiotherapy. However, the mechanisms of radiation-associated valvular disease are largely unknown. CAVD is considered to be an actively regulated disease process, mainly controlled by valvular interstitial cells (VICs). We hypothesize that radiation exposure catalyzes the calcific response of VICs and, therefore, contributes to the development of radiation-associated valvular disease. Methods and Results: To delineate the relationship between radiation and VIC behavior (morphology, calcification, and matrix turnover), two different in vitro models were established: (1) VICs were cultured two-dimensional (2D) on coverslips in control medium (CM) or osteogenic medium (OM) and irradiated with 0, 2, 4, 8, or 16 Gray (Gy); and (2) three-dimensional (3D) hydrogel system was designed, loaded with VICs and exposed to 0, 4, or 16 Gy of radiation. In both models, a dose-dependent decrease in cell viability and proliferation was observed in CM and OM. Radiation exposure caused myofibroblast-like morphological changes and differentiation of VICs, as characterized by decreased αSMA expression. Calcification, as defined by increased alkaline phosphatase activity, was mostly present in the 2D irradiated VICs exposed to 4 Gy, while after exposure to higher doses VICs acquired a unique giant fibroblast-like cell morphology. Finally, matrix turnover was significantly affected by radiation exposure in the 3D irradiated VICs, as shown by decreased collagen staining and increased MMP-2 and MMP-9 activity. Conclusions: The presented work demonstrates that radiation exposure enhances the calcific response in VICs, a hallmark of CAVD. In addition, high radiation exposure induces differentiation of VICs into a terminally differentiated giant-cell fibroblast. Further studies are essential to elucidate the underlying mechanisms of these radiation-induced valvular changes.
RESUMO
Radiation-induced cardiovascular disease is a well-known complication of radiation exposure. Over the last few years, planning for deep space missions has increased interest in the effects of space radiation on the cardiovascular system, as an increasing number of astronauts will be exposed to space radiation for longer periods of time. Research has shown that exposure to different types of particles found in space radiation can lead to the development of diverse cardiovascular disease via fibrotic myocardial remodeling, accelerated atherosclerosis and microvascular damage. Several underlying mechanisms for radiation-induced cardiovascular disease have been identified, but many aspects of the pathophysiology remain unclear. Existing pharmacological compounds have been evaluated to protect the cardiovascular system from space radiation-induced damage, but currently no radioprotective compounds have been approved. This review critically analyzes the effects of space radiation on the cardiovascular system, the underlying mechanisms and potential countermeasures to space radiation-induced cardiovascular disease.