title: The mechanism of the initial natriuresis after transjugular intrahepatic portosystemic shunt.
abstract: OBJECTIVE
  The pathogenesis of the delayed natriuresis after transjugular intrahepatic portosystemic shunt (TIPS) insertion is unknown. This was studied to elucidate the mechanism involved.
  
  
  METHODS
  In 12 patients with cirrhosis and refractory ascites after TIPS, systemic and renal hemodynamics, renal sodium handling, central blood volume, neurohumoral factors, and hepatic function were studied weekly after the shunt with the patients receiving a diet of 20 mmol sodium/day.
  
  
  RESULTS
  Two weeks after TIPS, the initial natriuresis (4 +/- 1 to 18 +/- 3 mmol/day; P < 0.05) was associated with significant reductions in corrected sinusoidal pressure (24.4 +/- 1.8 to 7.5 +/- 0.4 mm Hg; P < 0.001), proximal renal tubular reabsorption of sodium (P = 0.05), and renin-angiotensin-aldosterone activity (P < 0.05), but with significant systemic vasodilatation (P < 0.05). At 4 weeks, negative sodium balance was achieved (52 +/- 21 mmol/day; P < 0.01), despite continued systemic arterial vasodilatation, associated with significant increases in total central and cardiac volumes (P < 0.05) and normalization of serum aldosterone levels (P < 0.01). Four late responders were significantly older (P = 0.01) and had significantly lower baseline glomerular filtration rates (P = 0.02).
  
  
  CONCLUSIONS
  In cirrhosis, sinusoidal portal hypertension and an activated renin-angiotensin-aldosterone system seem to be important in the pathogenesis of sodium retention. Systemic vasodilatation without arterial underfilling does not prevent natriuresis. Delayed natriuresis after TIPS is associated with increasing age and pre-TIPS renal impairment.
authors.affiliation: Department of Medicine, University of Toronto, Ontario, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Wong
authors.forename: K
authors.initials: K
authors.lastname: Sniderman
authors.forename: P
authors.initials: P
authors.lastname: Liu
authors.forename: L
authors.initials: L
authors.lastname: Blendis
mesh_terms: D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000097:blood; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D008099:Liver / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009318:Natriuresis; D019168:Portasystemic Shunt, Transjugular Intrahepatic / Q000009:adverse effects*; D012083:Renin / Q000097:blood; D012964:Sodium / Q000378:metabolism
chemical_list: D000450:Aldosterone; D012964:Sodium; D012083:Renin