Assessment of Dry Body Weight in Maintenance Hemodialysis Patients by Plasma Levels of ANP and cGMP

Um, Hyun Ju; Kim, Hyang; Park, Eun Mee; Park, Jung Sik; Lee, Kyu Beck

Abstract

The precise measurement of fluid balance in hemodialysis patients is an important component for assessment of dialysis adequacy and predicting intradialytic morbidity. In most centers, fluid removal by ultrafiltration is targeted to a patient's dry weight, but dry weight estimated by trial-and-error method is often imprecise. ANP(atrial natriuretic peptide) and cGMP(cyclic guanosine 3', 5'-monophophate) are biochemical markers for volume overload. We hypothesized that plasma values of ANP and cGMP before and after hemodialysis might be useful for evaluating ideal dry body weight and volume status in maintenance hemodialysis patients. To test this hypothesis, we examined 36 stable hemodialysis patients without fluid overload for a minimum of three months at our hospital. In all patients, plasma ANP and cGMP were measured by radioimmunoassay(RIA) method immediately before and after hemodialysis. Thirteen normal healthy controls were studied to define the normal range of plasma ANP and cGMP value. We correlated plasma values of ANP and cGMP in paitents with corresponding difference of P(difference between actual weight and estimated ideal dry weight) and mean arterial blood pressure(MAP). The results are as follows : 1) Compared with healthy controls, the hemodialysis patients had significantly elevated plasma values of ANP and cGMP. The plasma ANP and cGMP values after dialysis were significantly decreased compared to those before dialysis(p<0.01). 2) There was positive correlation between the levels of ANP and cGMP(p<0.01). 3) Predialytic difference of P was significantly positive correlated to predialytic cGMP(r= 0.73, p<0.01). It was also appeared to be increased tendency by increasing value of predialytic ANP, but the difference was statistically not significant. 4) Predialytic MAP had significant positive correlation to predialytic ANP(r=0.47, p<0.01). It was also increased by predialytic cGMP, but the difference was statistically not significant. In conclusion, plasma values of ANP and cGMP might be helpful clinical markers for evaluating volume status and assessing dry weight in maintenance hemodialysis patients.