Abstract
To clarify the significance of resting PRA as an index of sodium balance in patients under chronic hemopialysis, we studied the resting PRA, sodium balance of the body and the clinical symptoms in 45 hemodialysis patients. Hypotensive drugs were discontinued at least for three months before the test. PRA was measured before (pre-dialysis PRA) and after the dialysis (postdialysis PRA) once a month, Hemodlalysls is performed in a recirculating dialysate supply system of 50 liter capacity, so the sampling of dialysate is easy at the end of the dialysis. “R” is calculatedd as an index of releasability of renin as follows:
(R=post-dialysis PRA/pre-dialysis PRA/removed sodium/removed water×100)
Patients were divided into three groups according to the mean value of resting PRA measured 3 times at monthly intervals: low renin group, 1-9 ng/ml ; normal renin group, 10-29 ng/ml, highh renin group, more than 30 ng/ml. 1) Resting PRA was decreased in accordance with the duration of dialysis and age. 2) R was also decreased in accordance with the duration of dialysis but not with age. 3) The incidence of low, normal and high renin groups were 35.6%, 42.2 and 22. 2, respectively. 4) The systolic blood pressure was not different among the three groups, while the diastolic blood pressure tended to be high in parallel with the renin levels. 5) The characteristics of low renin group was as follows; Both the amounts and concentrations of sodium removed by the preceding dialysis were low, R was low. Intake of sodium was high, age was advanced, long duration of dialysis, and slight degree of organ damage. 6) The characteristics of normal renih group was as follows; All parameters are intermediate between those of low and high renin groups. 7) The characteristics of high renin group was as follows ; Both the amounts and concentrations of rmoved sodium by the preceding dialysis were high, R was highs Intake of sodium was low, young age, short duration of dialysis, advanced organ damage, and hyponatremia. From these results, it seems likely that the resting levels of PRA in chronic dialysis patients are reflecting the state of sodium balance in the body, and renin is contributing to the hypertension, especially to the elevation in diastolic blood pressure in patients belonging to thee high renin group.
