title: Hyponatremia and its association with the neurohormonal activity and adverse clinical events in children and young adult patients after the Fontan operation.
abstract: BACKGROUND
  Hyponatremia (HN) is relatively common in adults with congenital heart disease and is a powerful predictor of mortality. However, the precise relationship of HN to the Fontan pathophysiology remains unknown.
  
  
  OBJECTIVE
  Our study aimed to clarify the association of HN to the Fontan pathophysiology.
  
  
  RESULTS
  We measured the plasma sodium (Na) level in 169 consecutive Fontan patients (78 children) and HN (≤137 mEq/L) was observed in 50 patients (30% of the total patients, 31% of the children). The HN patients showed a lower peak oxygen uptake (VO(2) ) with a greater New York Heart Association class (P < .0001). The plasma level of norepinephrine (NE), rennin activity (PRA), arginine vasopressin, central venous pressure (CVP) and medications were associated with the Na levels and the NE, PRA, and diuretic use were the independent determinants (P < .01-.0001). The plasma B-type natriuretic peptide was not correlated with the Na levels. In the children, diuretic use and the PRA independently determined the Na levels without any association to the CVP or peak VO(2) . During a median follow-up of 2.1 years, the HN in addition to the CVP and peak VO(2) independently predicted the unscheduled hospitalizations in all patients, while the HN was the only independent predictor of the hospitalizations in the adult patients (hazard ratio: 3.1, 95% confidence interval 1.2-8.0, P = .021).
  
  
  CONCLUSIONS
  Child and adult Fontan patients exhibited a high prevalence for HN that closely reflected some neurohumoral activation and predicted adverse clinical events, especially in adult Fontan patients.
authors.affiliation: Departments of Pediatric Cardiology, National Cardiovascular Center, Osaka, Japan. hohuchi@hsp.ncvc.go.jp
authors.forename: Hideo
authors.initials: H
authors.lastname: Ohuchi
authors.forename: Jun
authors.initials: J
authors.lastname: Negishi
authors.forename: Shin
authors.initials: S
authors.lastname: Ono
authors.forename: Akira
authors.initials: A
authors.lastname: Miyake
authors.forename: Naoki
authors.initials: N
authors.lastname: Toyota
authors.forename: Wataru
authors.initials: W
authors.lastname: Tamaki
authors.forename: Aya
authors.initials: A
authors.lastname: Miyazaki
authors.forename: Osamu
authors.initials: O
authors.lastname: Yamada
mesh_terms: D000293:Adolescent; D000328:Adult; D001127:Arginine Vasopressin / Q000097:blood; D015415:Biomarkers / Q000097:blood; D002496:Central Venous Pressure; D002648:Child; D005260:Female; D018729:Fontan Procedure / Q000009:adverse effects*; D006330:Heart Defects, Congenital / Q000097:blood / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D007564:Japan; D053208:Kaplan-Meier Estimate; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000097:blood; D009638:Norepinephrine / Q000097:blood; D010101:Oxygen Consumption; D016016:Proportional Hazards Models; D012044:Regression Analysis; D012083:Renin / Q000097:blood; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012964:Sodium / Q000097:blood*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001127:Arginine Vasopressin; D020097:Natriuretic Peptide, Brain; D012964:Sodium; D012083:Renin; D009638:Norepinephrine