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Differential Renal Studies in the Diagnosis of Hypertension Due to Renal Arterial Stenosis: Validity of Calculating Comparative Urinary Volume Reduction from the Comparative Urinary Creatinine Concentrations
Vol. 94, July Printed in U.S.A.
THE JOURNAL OF UROLOGY
Copyright © 1965 by The Williams & Wilkins Co.
DIFFERENTIAL RENAL STUDIES IN THE DIAGNOSIS OF HYPERTENSION DUE TO RENAL ARTERIAL STENOSIS: VALIDITY OF CALCULATING COMPARATIVE URINARY VOLUME REDUCTION FROM THE COMPARATIVE URINARY CREATININE CONCENTRATIONS ROBERT BIRCHALL
AND
HUGH M. BATSON, JR.
From the Department of Medicine, Ochsner Clinic, New Orleans, Louisiana
The reliability of differential renal studies in the diagnosis of hypertension due to renal arterial stenosis is well established. There is still disagreement about how the test should be performed and how the results should be expressed. Sorn.e observers ern.phasize comparative urinary volume, comparative urinary sodium concentration, comparative urinary creatinine concentration, or comparative osmolality ;1 - 5 others en1.phasize some combination of these, such as the proportional relation between the concentration of so-
UNa ra t'10 h as . U nary vo1ume or on a compara t 1ve Cr.
important implications. The person who relies on comparative urinary volume must either use large catheters, which completely occlude the ureter, or place the patient in the Trendelenburg position, use a small catheter plus siphonage 9 or suction10 and hope pelvic peristalsis does not produce ureteral leakage. The person who relies on a comparative
~Na Cr.
ratio can disregard ureteral leakage
and use small ureteral catheters with precision, thus increasing accuracy and greatly reducing the morbidity that follows the procedure. 11 This problem actually resolves itself if one remembers that both the final volume of urine passed and the final urinary concentration of creatinine depend almost entirely on the amount of water reabsorbed from the glomerular filtrate. The hypotensive or affected kidney can be characterized as a thirsty kidney, whose urinary excretion, despite maximum water diuresis, is small in volume and high in creatinine. 1 How small in volume and how high in creatinine depends primarily on how much water is reabsorbed across the collecting ducts. To the extent that this is true, in the presence of renal arterial stenosis it should be possible to use urinary volume and urinary creatinine concentration interchangeably, and actually to calculate, from the comparative difference in creatinine concentration, what the comparative difference in urinary volume would have been if there had been no ureteral leakage. Table 1, cal-
. , ( -USodium ) . , 1s. d mm an d crea t·mme - - m t h e urme U Creatinine suing simultaneously from each ureter. 1 • 3 , 6- 8 Whether reliance is placed on comparative uriAccepted for publication December 11, 1964. 1 Birchall, R., Batson, H. M. and Moore, C. B.: Hypertension due to unilateral renal arterial obstruction; preliminary observations on the contribution of differential renal clearance studies. Amer. Heart J., 56: 616-628, 1958. 2 Schlegel, J. U., Savlov, E. D. and Gabor, F.: Some studies in renal hypertension. J. Urol., 81: 581-595, 1959. 3 Rapoport, A.: Modification of the Howard test for the detection of renal-artery obstruction. New Engl. J. Med., 263: 1159-1165, 1960. 4 Connor, T. B., Thomas, W. C., Jr., Haddock, L. and Howard, J.E.: Unilateral renal disease as a cause of hypertension; its detection by ureteral catheterization studies. Ann. Intern. Med., 52:
544-559, 1960. 5 Stamey, T. A., Nudelman, I. J., Good, P.H., Schwentker, F. N. and Hendricks, F.: Functional characteristics of renovascular hypertension. Medicine, 40: 347-394, 1961. 6 Birchall, R., Batson, H. M., Jr. and Brannan, W.: Contribution of differential renal studies to the diagnosis of renal arterial hypertension with · Usodium A mer. J . emp h as1S On th e va1Ue Of U Oreatinine.
Med., 32: 164-170, 1962. 7 Madeloff, M. S., Schwartz, F. D., Borges, F. J., Entwisle, G., Revell, S. T., Jr. and Young, J. D., Jr.: Differential renal clearance patterns in the evaluation of hypertension. J. Urol., 87: 258-
' Yeates, W. K.: Differential renal function tests: a technique for the collection of urine specimens. Lancet, 2: 1253-1254, 1963. 10 Winter, C. C.: The performance of divided renal function tests in renal hypertension: a practical method. J. Urol., 91: 203-205, 1964. 11 Smith, H. W.: The Kidney: Structure and Function in Health and Disease. New York: Oxford University Press, 1951, p. 43.
272, 1962. 8 Birchall, R., Batson, H. M., Jr. and Anderson, E. G.: Diagnosis of hypertension due to renal arterial stenosis. Circulation, 29: 6-13, 1964.
4
5
DIFFERENTIAL RENAL STUDIES FOR HYPERTENSION TABLE
1. Data on 5 patients illustrating accuracy of calculation of urinary volume from comparative creatinine concentrations
I Vol. (VJ
Pt.
Kidney lVIl./Min
Unaffected Affected
V
8 .81 I 0.11 0.61 l.64
I AITeeted
% Vol. ~eduction
Creatinine Mg./100 Ml. l\ieasured*
I
I
I Unaffected ~10.86
2
I
~I~~
I
9 9 i 107
91
I
I
28.8 592
95
92
95
4
Unaffected Affected
1.50 0.13
50.3 I 495
91
90
5
Unaffected Affected
12 202
98
94
I
* (V)
I 122
83
96 28.8
I- - - -
UNa Ucr.
-1-
Vol.
138.5 28
I I
'
I/UNa
UNa
+
1
Ucr. +
~ 0
v
- - ----
21 2
93
95
1..5
1909 99 .4
4.24 0.05
141.9 1.7
[)9
99
320
95 1~9;--
-5 51 o.2s
I
1_ _
7.48 --------
- ----
0.22 9.09
210 163
28
17.1 103
4.60 0.11
DNa
---
93
3.281 0.30 0.26 3 .85 0.67 7.69
Urine Sodium mEq/L.
Calculated From Creat. t
Unaffected Affected
3
] % Difference in:
I
2.75 I 0.06
206 7 3.6
I
98 I
98
-------
I
97 98 I 8.08 440.9 I 3 .1 28.3 0 .14 I I I
99
I
unaffected - (V) affected X lOO. (V) unaffected
(Ucrl a,ffected - (Uc,.) unaffected (Uc,) affected
t - - - - - - - - - - - X 100. (UNa) - unaffected - (UN,) - - affected Uc,. Uc,. 100 X . UNa - - unaffected Uc,.
+ \ +
(+ /UNa)
§
unaffected
+
+
(UNa)
(UNa)
affected X 100.
unaffected
culated frorn data obtained in 5 randomly selected patients with hypertension due to renal arterial stenosis confirmed at operation, illustrates the accuracy with which the percentage reduction of urinary volume can be calculated from the comparative creatinine concentrations. It also illustrates the validity of expressing the Howard test as UNa , and so mathematically in1 .
Vol. creasing its sensitivity. It is the problem of leakage and size of catheter that makes this approach . t lmn t h e -U--. UNa Iess attractrve Or.
In view of this, in the routine performance of differential renal studies, it is suggested that small catheters be used and leakage be ignored. If a figure for comparative urinary volurn.e is desired, it can be calculated from the comparative creatinine concentrations. In the unusual patient in whom it seems mandatory to establish separately the function of each kidney, a full differential inulin-P AH clearance will be required, and here, of course, leakage is anathema and timed volumes are essential. Since, as previously noted, the urinary concentrations of sodium and creatinine on the affected
6
BIRCHALL AND BATSON, JR.
side move in opposite directions, the sensitivity of the test is greatly increased if reliance is placed on the sodium-creatinine ratio rather than on urinary volume, sodium concentration, or creatinine concentration alone. 1 • 3 • 5-s Obviously, nothing is gained by reliance on both comparative
urinary volume and comparative creatinine or inulin concentration, since both reflect the same process (reabsorption of water). These observations are not applicable to the patient with a segrn.ental arterial lesion and consequent loss of nephron mass.
THE JOURNAL OF UROLOGY
Copyright © 1965 by The Williams & Wilkins Co.
DIFFERENTIAL RENAL STUDIES IN THE DIAGNOSIS OF HYPERTENSION DUE TO RENAL ARTERIAL STENOSIS: VALIDITY OF CALCULATING COMPARATIVE URINARY VOLUME REDUCTION FROM THE COMPARATIVE URINARY CREATININE CONCENTRATIONS ROBERT BIRCHALL
AND
HUGH M. BATSON, JR.
From the Department of Medicine, Ochsner Clinic, New Orleans, Louisiana
The reliability of differential renal studies in the diagnosis of hypertension due to renal arterial stenosis is well established. There is still disagreement about how the test should be performed and how the results should be expressed. Sorn.e observers ern.phasize comparative urinary volume, comparative urinary sodium concentration, comparative urinary creatinine concentration, or comparative osmolality ;1 - 5 others en1.phasize some combination of these, such as the proportional relation between the concentration of so-
UNa ra t'10 h as . U nary vo1ume or on a compara t 1ve Cr.
important implications. The person who relies on comparative urinary volume must either use large catheters, which completely occlude the ureter, or place the patient in the Trendelenburg position, use a small catheter plus siphonage 9 or suction10 and hope pelvic peristalsis does not produce ureteral leakage. The person who relies on a comparative
~Na Cr.
ratio can disregard ureteral leakage
and use small ureteral catheters with precision, thus increasing accuracy and greatly reducing the morbidity that follows the procedure. 11 This problem actually resolves itself if one remembers that both the final volume of urine passed and the final urinary concentration of creatinine depend almost entirely on the amount of water reabsorbed from the glomerular filtrate. The hypotensive or affected kidney can be characterized as a thirsty kidney, whose urinary excretion, despite maximum water diuresis, is small in volume and high in creatinine. 1 How small in volume and how high in creatinine depends primarily on how much water is reabsorbed across the collecting ducts. To the extent that this is true, in the presence of renal arterial stenosis it should be possible to use urinary volume and urinary creatinine concentration interchangeably, and actually to calculate, from the comparative difference in creatinine concentration, what the comparative difference in urinary volume would have been if there had been no ureteral leakage. Table 1, cal-
. , ( -USodium ) . , 1s. d mm an d crea t·mme - - m t h e urme U Creatinine suing simultaneously from each ureter. 1 • 3 , 6- 8 Whether reliance is placed on comparative uriAccepted for publication December 11, 1964. 1 Birchall, R., Batson, H. M. and Moore, C. B.: Hypertension due to unilateral renal arterial obstruction; preliminary observations on the contribution of differential renal clearance studies. Amer. Heart J., 56: 616-628, 1958. 2 Schlegel, J. U., Savlov, E. D. and Gabor, F.: Some studies in renal hypertension. J. Urol., 81: 581-595, 1959. 3 Rapoport, A.: Modification of the Howard test for the detection of renal-artery obstruction. New Engl. J. Med., 263: 1159-1165, 1960. 4 Connor, T. B., Thomas, W. C., Jr., Haddock, L. and Howard, J.E.: Unilateral renal disease as a cause of hypertension; its detection by ureteral catheterization studies. Ann. Intern. Med., 52:
544-559, 1960. 5 Stamey, T. A., Nudelman, I. J., Good, P.H., Schwentker, F. N. and Hendricks, F.: Functional characteristics of renovascular hypertension. Medicine, 40: 347-394, 1961. 6 Birchall, R., Batson, H. M., Jr. and Brannan, W.: Contribution of differential renal studies to the diagnosis of renal arterial hypertension with · Usodium A mer. J . emp h as1S On th e va1Ue Of U Oreatinine.
Med., 32: 164-170, 1962. 7 Madeloff, M. S., Schwartz, F. D., Borges, F. J., Entwisle, G., Revell, S. T., Jr. and Young, J. D., Jr.: Differential renal clearance patterns in the evaluation of hypertension. J. Urol., 87: 258-
' Yeates, W. K.: Differential renal function tests: a technique for the collection of urine specimens. Lancet, 2: 1253-1254, 1963. 10 Winter, C. C.: The performance of divided renal function tests in renal hypertension: a practical method. J. Urol., 91: 203-205, 1964. 11 Smith, H. W.: The Kidney: Structure and Function in Health and Disease. New York: Oxford University Press, 1951, p. 43.
272, 1962. 8 Birchall, R., Batson, H. M., Jr. and Anderson, E. G.: Diagnosis of hypertension due to renal arterial stenosis. Circulation, 29: 6-13, 1964.
4
5
DIFFERENTIAL RENAL STUDIES FOR HYPERTENSION TABLE
1. Data on 5 patients illustrating accuracy of calculation of urinary volume from comparative creatinine concentrations
I Vol. (VJ
Pt.
Kidney lVIl./Min
Unaffected Affected
V
8 .81 I 0.11 0.61 l.64
I AITeeted
% Vol. ~eduction
Creatinine Mg./100 Ml. l\ieasured*
I
I
I Unaffected ~10.86
2
I
~I~~
I
9 9 i 107
91
I
I
28.8 592
95
92
95
4
Unaffected Affected
1.50 0.13
50.3 I 495
91
90
5
Unaffected Affected
12 202
98
94
I
* (V)
I 122
83
96 28.8
I- - - -
UNa Ucr.
-1-
Vol.
138.5 28
I I
'
I/UNa
UNa
+
1
Ucr. +
~ 0
v
- - ----
21 2
93
95
1..5
1909 99 .4
4.24 0.05
141.9 1.7
[)9
99
320
95 1~9;--
-5 51 o.2s
I
1_ _
7.48 --------
- ----
0.22 9.09
210 163
28
17.1 103
4.60 0.11
DNa
---
93
3.281 0.30 0.26 3 .85 0.67 7.69
Urine Sodium mEq/L.
Calculated From Creat. t
Unaffected Affected
3
] % Difference in:
I
2.75 I 0.06
206 7 3.6
I
98 I
98
-------
I
97 98 I 8.08 440.9 I 3 .1 28.3 0 .14 I I I
99
I
unaffected - (V) affected X lOO. (V) unaffected
(Ucrl a,ffected - (Uc,.) unaffected (Uc,) affected
t - - - - - - - - - - - X 100. (UNa) - unaffected - (UN,) - - affected Uc,. Uc,. 100 X . UNa - - unaffected Uc,.
+ \ +
(+ /UNa)
§
unaffected
+
+
(UNa)
(UNa)
affected X 100.
unaffected
culated frorn data obtained in 5 randomly selected patients with hypertension due to renal arterial stenosis confirmed at operation, illustrates the accuracy with which the percentage reduction of urinary volume can be calculated from the comparative creatinine concentrations. It also illustrates the validity of expressing the Howard test as UNa , and so mathematically in1 .
Vol. creasing its sensitivity. It is the problem of leakage and size of catheter that makes this approach . t lmn t h e -U--. UNa Iess attractrve Or.
In view of this, in the routine performance of differential renal studies, it is suggested that small catheters be used and leakage be ignored. If a figure for comparative urinary volurn.e is desired, it can be calculated from the comparative creatinine concentrations. In the unusual patient in whom it seems mandatory to establish separately the function of each kidney, a full differential inulin-P AH clearance will be required, and here, of course, leakage is anathema and timed volumes are essential. Since, as previously noted, the urinary concentrations of sodium and creatinine on the affected
6
BIRCHALL AND BATSON, JR.
side move in opposite directions, the sensitivity of the test is greatly increased if reliance is placed on the sodium-creatinine ratio rather than on urinary volume, sodium concentration, or creatinine concentration alone. 1 • 3 • 5-s Obviously, nothing is gained by reliance on both comparative
urinary volume and comparative creatinine or inulin concentration, since both reflect the same process (reabsorption of water). These observations are not applicable to the patient with a segrn.ental arterial lesion and consequent loss of nephron mass.