Peritoneovenous shunting restores atrial natriuretic factor responsiveness in refractory hepatic ascites

Sodium retention in cirrhosis has been attributed to an imbalance between vasoconstrictive, antinatriuretic forces such as the renin aldosterone angiotensin system and the sympathetic nervous system, and vasodilatory, natriuretic agents such as atrial natriuretic factor (ANF). Patients with diuretic resistant refractory ascites may require peritoneovenous shunting (PVS) to control ascites.

To study the factors responsible for the improvement in sodium homeostasis post-PVS, we compared the response to ANF infusion before and 1 month after PVS in 6 patients with massive ascites.

Before PVS, sodium excretion at baseline and in response to ANF infusion was blunted but became more normal post-PVS. ANF infusion post-PVS induced a significant increase in the glomerular filtration rate and filtration fraction and also in distal delivery of sodium. ANF's distal effect of increasing the fractional excretion of distally delivered sodium was present pre-PVS and was not significantly increased post-PVS. Changes in sodium handling were accompanied by a significant decrease in antinatriuretic forces (baseline aldosterone, 2079 +/- 507 vs. 647 +/- 17 nmol/L; P < 0.04) post-PVS.

The improvement in sodium homeostasis and response to ANF infusion post-PVS appears to be associated with the decrease in antinatriuretic forces with the loss of massive refractory ascites. Thus, PVS restores the balance toward ANF responsiveness.