The Usefulness of Monitoring of Transtubular Potassium Gradient and Spot Urine [Na]/[K] Ratio in the management of Cirrhotic Ascites

Lim, Young Seok; Lee, Hyo Suk; Yoon, Jung Hwan; Han, Jin Suk; Kim, Chung Yong

Abstract

BACKGROUND/AIMS: Transtubular potassium gradient(TTKG) is known as the most accurate indicator of aldosterone activity. TTKG may be used to monitor the effectiveness of aldosterone antagonist which is prescribed generally for the management of cirrhotic ascites. Spot urine [Na]/[K] ratio may also be used for the same purpose.
METHODS
After measuring TTKG, spot urine [Na]/[K] ratio, and plasma aldosterone concentration in each of the 23 patients all who had cirrhotic ascites, 100 mg of spiron-olactone was prescribed to be taken daily for 5 days. When no diuretic response occurred and TTKG was more than 3.5 at the end of 5 days, the dose of spironolactone was increased by 100 mg/day at the interval of 5 days until TTKG decreased to below 3.5. Furosemide was added to the non-responders if their TTKG had dropped to below 3.5.
RESULTS
Basal plasma concentration of aldosterone was higher than upper normal limit in 13(57%) patients, and correlated with TTKG significantly(r=0.60, p=0.002). TTKG was calculated to be 3.5+/-0.67 when assuming the aldosterone activity has been completely blocked. Spot urine [Na]/[K] ratio had significant negative correlation with TTKG before and after the administration of spironolactone. In most patients, diuretic response appeared with the fall of TTKG (especially below 3.5) and with the rise of spot urine [Na]/[K] ratio. In patients who did not respond to a low dose spironolactone, further treatment plan (to increase dose of spironolactone or to add furosemide) was guided by TTKG, and all were successful.
CONCLUSIONS
TTKG and spot urine [Na]/[K] ratio are good indicators of aldosterone activity, and might be used as useful guidelines in the diuretic management of cirrhotic ascites.