Effect of Renal Transplantation on Obstructive Sleep Apnea in End Stage Renal Disease Patients (SASinTx) (SASinTx)

• Reduction of the obstructive sleep apnea severity [ Time Frame: six months after renal transplantation ]
  Reduction of the obstructive sleep apnea severity, measured by attended polysomnography, six months after renal transplantation
  
  

• Reduction in nocturnal leg fluid volume shift between the legs and the neck [ Time Frame: six months after renal transplantation ]
  Reduction in nocturnal leg fluid volume shift between the legs and the neck, measured by bioimpedance and neck circumference six months after renal transplantation
  
  
• Relationship between overhydration, leg fluid volume shift, ankle and neck circumference and the severity of obstructive sleep apnea [ Time Frame: at baseline and six months after renal transplantation ]
  Relationship between overhydration (measured by bioimpedance), leg fluid volume shift, ankle and neck circumference and the severity of obstructive sleep apnea
  
  
• Change in the severity of the periodic limb movement disorder (PLMD) [ Time Frame: six months after renal transplantation ]
  Change in the severity of the periodic limb movement disorder (PLMD)
  
  
• Change in the severity of central sleep apnea [ Time Frame: six months after renal transplantation ]
  Change in the severity of central sleep apnea
  
  

Obstructive sleep disordered breathing is more prevalent in end stage kidney disease patients than in the general population, and may participate to the increased cardiovascular mortality observed in this group of patients. Despite a significant increase in knowledge about the harmful effects of obstructive sleep apnea, the pathophysiological mechanisms are poorly understood. Recent observations suggest a causative relationship between overnight fluid displacement from the legs to the neck soft and the severity of obstructive sleep apnea. This mechanism was demonstrated in otherwise healthy subjects, in heart failure patients, and in patients with venous insufficiency. We thus suspect that this pathophysiologic mechanism could explain the increased prevalence of obstructive sleep apnea in patients with fluid overload, including chronic renal failure.

The purpose of this study is to investigate the effect of renal transplantation on fluid overload and its consequence on the severity of obstructive sleep apnea, in patients with end stage chronic kidney disease. It aims further to investigate the relationship between overhydration, nocturnal rostral fluid shift and the severity of sleep apnea.

The severity of obstructive sleep apnea is measured by two attended polysomnographies, a baseline PSG performed before and a follow-up PSG performed 6 month after renal transplantation. Overhydration and leg fluid are evaluated by bioimpedance, performed at the beginning and at the end of each polysomnography. Patients who are not already transplanted 6 months after the baseline PSG will be re-assessed and will be analyzed as control group.