The use of peritoneovenous shunting in unravelling the pathogenesis of ascites in cirrhosis.

In a series of studies, peritoneovenous shunting (PVS) has been used to dissect out some of the many factors involved in salt and water retention associated with hepatic ascites. Careful metabolic studies showed that, immediately following PVS, diuresis and natriuresis were associated with a marked rise in cardiac output, renal plasma flow and creatinine clearance, and a significant fall in the elevated serum aldosterone and plasma renin activity to within the normal range. Despite these changes, sodium excretion in these patients remained abnormal when challenged with a high salt diet. In contrast, an immediate increase in water excretion was not associated with a reduction in the elevated antidiuretic hormone (ADH) levels which do, however, decrease to some extent after 2 weeks. Thus, in the long term, these cirrhosis patients will have improved systemic and renal hemodynamics and function and normalization of the renin-aldosterone axis and ADH, yet will still have a "sodium-retaining lesion," the nature of which still needs to be elucidated.