Refractory ascites: definition, pathogenesis and treatment.

Refractory ascites, that is ascites which cannot be mobilized by low sodium diet and maximal doses of diuretics (up to 400 mg spironolactone or potassium canrenoate and 160 mg furosemide per day), occurs in 5% of cirrhotic patients with ascites. The development of refractory ascites is mainly related to the progression of arterial vasodilation-mediated vascular underfilling and to the imbalance between reduced synthesis of renal vasodilating factors (especially renal prostaglandins) and extreme activation of vasoconstricting systems. Further features include increased sodium reabsorption in the proximal tubule and altered pharmacokinetics and pharmacodynamics of diuretics. In patients with impaired renal function (as is the case for most patients with refractory ascites), the marked reduction of renal perfusion and glomerular filtration rate, with the consequent decrease of filtered sodium load, becomes the main pathogenetic factor. The principal therapeutic options for refractory ascites include repeated paracentesis and implantation of the LeVeen shunt. Paracentesis is a rapid and safe procedure to remove ascites, but it does not correct sodium retention. Ascites recurrence, therefore, may occur after a brief interval. The LeVeen shunt allows for better long-term control of ascites, but severe complications may supervene, and shunt occlusion is common. Neither therapeutic procedure improves survival. Different experimental therapeutic procedures have been proposed. Administration of ornipressin corrects hyperdynamic circulation and improves renal function. Thromboxane synthase inhibitors, by reducing renal synthesis of thromboxane A2, potentiate the diuretic and natriuretic response to furosemide. More invasive procedures, including portosystemic shunt and transjugular intrahepatic stent, are rarely used in the treatment of refractory ascites.(ABSTRACT TRUNCATED AT 250 WORDS)