RENAL HYPERTENSION

CLINICAL AND SOME EXPERIMENTAL STUDIES

Abstract

1) Clinical analysis on 21 cases of renal hypertension experienced at Yokohama City University Hospital in the past five years and on 185 reported cases in the past Japanese medical literature are presented.
The conclusion is as follows: No definite preponderance on age and sex was found. Family history, past history, chief complaints, and urinalysis had little contribution to the diagnosis of renal hypertension.
Reno-vascular hypertensive groups were mostly caused by arteriosclerosis, thickening of arterial intima and by aneurysm.
Renal parenchymal hypertensive groups were due to pyelonephritis, hydronephrosis, and hypoplastic kidneys.
2) Several interesting cases including followings are presented: Bilateral renal artery stenosis associated with atypical coarctation of the aorta in 20 year old female was treated by spleno-renal anastomosis and aorto-renal bypass graft. Her hypertension was corrected.
Moderate hypertension, hematuria and polycythemia were found in 33 year old male whose left renal arterial branch was obstructed. Erythropoietin bioassay was not conclusive, however, polycythemia vera and other disorders causing polycythemia were excluded in this case, polycythemia of renal origin was suspected. (renal ischemia→erythropoietin production→polycythemia). Other symptoms were also due to renal ischemia, i. e. increased permeability of capillary bed in glomeruli due to hypoxia caused hematuria and renin released from the ischemic kidney resulted in hypertension through Gold-blatt mechanism.
Hormonally non-functioning giant adrenal cyst causing left renal artery compression and stretching was removed in 62 year old male and hypertension corrected.
3) Intravenous pyelogram (contrast media injected rapidly, films taken also at early phase) was found to be very valuable in detecting renal hypertension when combined with ¹³¹I Hippuran renogram.
Shortening of the longitudinal axis in nephrogram, hypoconcentration, and delay in appearance of nephrogram or pyelogram were usual findings in IVP.
1.5cm or more difference of the longitudinal axis in nephrogram in hypertensives is an absolute indication to subsequently taking renal arteriogram.
More than 2 findings on pyelogram are also indication to arteriogram.
More attention should be given to the ureteric indentations on pyelogram due to compression of the ureter by well developed ureteric arteries as collaterals to the ischemic kidney.
4) Some discussions especially on side effects were made on selective renal arteriogram in comparing with aortogram. Comparison of renal artery stenosis with and without renal ischemia was done.
Renal artery stenosis causing hypertension is prone to have stenosis ratio bellow 0.50, post-stenotic dilatation, and well developed collaterals.
2 cases of renal arterial stenosis without renal ischemia due to hypersensitive angitis are presented.
5) Seperated Renal Function Mannitolization Test (after collection of sparated urine under oral diuresis, rapid infusion of 20% mannitol solution intravenously may reverse Na, Cl, K, Urea-N, or creatinine concentration ratio between ischemic and non-ischemic kidney urine) can prove presense of renal ischemia.
Proposal on SRF index (Separated Renal Function index) was made:
SRF index=number of positive tests indidating ischemic change/total number of tests
Closer the SRF index to 1.0, more reliable that the kidney is ischemic. SRF index can be applied in every occasion of separated renal function tests even if bladder leakage is present.
6) After experimental renal ischemia such as total infarction, partial infarction, or Goldblatt kidneys was produced in rabbits, serum and urinary alkaline phosphatase level changes were investigated.
Alkaline phosphatase, rich in proximal convoluted tubuli was released only transientry under these ischemic conditions.
However, clinically, one third cases of renovascular hypertensives showed e