Long-term follow-up of surgical renal hypertension

Long-Term Follow-up of Surgical Renal Hypertension By R.G. Taylor, A.F. A z m y , and D.G. Young

Glasgow, Scotland 9 A retrospective study of 42 children with hypertension secondary to renal disease is presented. Thirty-three had scarred kidneys, 5 had renovascular disease, 2 had renal venous thrombosis, 1 had an angiomatous malformation of the upper pole of the kidney, and 1 had glomerulonephritis. Twenty-six children w e r e managed surgically. The etiology, presentation, and management are presented. Followup varied from 2 to 14 years and the outcome is discussed. 9 1987 by Grune & Stratton. Inc.

elapsed in these 20 children from initial presentation with a urinary tract problem to diagnosis of hypertension varied from 3 months to 10 years (Table 1). Fourteen patients presented with symptoms directly related to the hypertension, viz headache, vomiting, and epistaxis. All of these children had a diastolic blood pressure of over 110 mmHg. The underlying renal disease was detected during investigation of these cases. The remaining two children were noted to have hypertension as an incidental finding on routine examination.

INDEX WORDS: Renal hypertension.

During the period of the study, the methods of investigation have varied. Investigations included intravenous urography (IVU), micturating cystourethrography, isotope renography, 99TC DMSA scanning, and creatinine clearance or EDTA clearance. Renal vein renin estimations (RVR) were performed when the initial investigations indicated unilateral renal disease. Renal arteriography was performed when renovascular disease was suspected. Thirty-three patients were found to have scarred kidneys on IVU and of these 24 were females. The age at presentation with hypertension ranged from 4 to 16 years (Table 2). Twenty of these patients were thought to have unilateral disease. Of the remaining 13, one kidney was predominantly affected in nine with only a single scar on the contralateral kidney, whereas both kidneys had multiple scars in four patients. Only three patients had impaired renal function as measured by creatinine clearance or EDTA clearance. Isotope renography was performed in 30 of the 33 patients with scarred kidneys. In 22, the diseased side showed poor function or no function, while in six it was assessed as moderate. In the remaining two, only slight reduction in function was shown. Apart from a case of duplex kidney, only the patients with poor function or no function were submitted to surgery in accordance with a policy of attempting to retain the maximum number of functioning nephrons. Those patients with moderate function were managed by conservative medical measures irrespective of the results of RVR studies. RVR studies were done in 28 of these 33 patients.4 Fifteen patients showed evidence of excess renin production in one kidney, whereas the remaining 13 did not show lateralization. Five patients were found to have renovascular hypertension. Two of these had generalized fibromuscular dysplasia, although one was initially thought to have unilateral renal artery stenosis and was subjected to nephrectomy before the true nature of the disorder was recognized. Another child had renal artery stenosis in a solitary kidney. Bilateral renal artery stenosis with coarctation of the aorta was present in one, and the remaining patient had a renal artery aneurysm. Renal venous thrombosis in infancy was the etiology of the hypertension in two patients. Investigation in one revealed a shrunken nonfunctioning kidney, and in the other patient function in both kidneys was preserved but RVR studies showed lateralization. An angiomatous malformation was found in the upper pole of the left kidney in a 12-year-old boy who presented with hypertensive encephalopathy (blood pressure 190/130 mmHg). RVR estimations showed increased output from the affected kidney. The remaining patient was an 11-year-old boy who presented with glomerulonephritis and persistent hypertension (150/110 mmHg). Investigation revealed a nonfunctioning left kidney with lateralization of RVR levels to this side.

YPERTENSION in children has received little

attention because of its infrequency and also H because of the relative difficulty of recording the blood

pressure accurately in infants and younger children. There have been several reports 1-3 of pediatric renal hypertension, but none concentrating on long-term follow-up. A review of 42 children with hypertension, who have been investigated with a view to surgical intervention for correction of the disease, is presented. Only patients with primary renal disease have been included. Those presenting with hypertension caused by shunt nephritis or by urinary tract obstruction due to tumor or malformation have been excluded. MATERIALS A N D METHODS We have reviewed the records of 42 patients admitted to the Royal Hospital for Sick Children, Glasgow between 1970 and 1984 in whom blood pressure was greater than the 97th percentile for their age. With the exception of one infant, the diastolic blood pressure was in excess of 85 mmHg and systolic pressures ranged up to 230 mmHg. There were 27 female and 15 male patients, ages ranging from the first month of life to 16 years. The mean age was 9.5 years. The diagnosis of hypertension was made in 26 patients at presentation or during follow-up of urinary tract infection. Hypertension was noted in 6 of 26 patients at the time of initial presentation with urinary tract symptoms, while 18 were only found to have hypertension during subsequent follow-up. The remaining two had been investigated previously and were known to have a urinary tract anomaly before presenting again with hypertension. The time that

From the Department of Paediatric Surgery, Royal Hospital for Sick Children, Yorkhill, Glasgow, Scotland Presented at the 33rd Annual Congress of the British Association of Paediatric Surgeons, Birmingham, England, July 16-18, 1986. Address reprint requests to A.F. Azmy, FRCS, Department of Paediatric Surgery, Royal Hospital for Sick Children Yorkhill, Glasgow, G3 8S J, Scotland. 9 1987 by Grune & Stratton, Inc. 0022-3468/87/2203-0011 $03.00/0

228

Investigation

Journal of Pediatric Surgery, Vol 22, No 3 (March), 1987: pp 228- 230

FOLLOW-UP OF SURGICAL RENAL HYPERTENSION

229

Table 1. Period Between Diagnosis of Urinary Tract Disorders and Diagnosis of Hypertension Years

Total

0-2 2-4 4-6 6-8 8-10

2 2 5 9 2 2O

RESULTS

The general policy adopted in the management of these patients was one of preservation of the maximum amount of renal tissue. One patient died soon after nephrectomy for renal artery aneurysm, the cause of death being an overwhelming enterocolitis. Three patients were lost to follow-up, but were normotensive when discharged. The follow-up of the remaining patients was from 2 to 14 years after diagnosis. Analysis of the IVUs of the 33 patients with renal scarring showed that outcome was related to the degree of scarring (Table 3). Of the 20 patients with unilateral scarring, 19 were normotensive at follow-up. In the one hypertensive patient, RVR studies did not show lateralization and isotope renography showed moderate function. Fourteen patients had a nephrectomy (12) or partial nephrectomy (2); of these 11 under current reviewed are normotensive, as were the remaining three prior to discharge and moving from this area. Follow-up is from 2 to 11 years with a mean of 5 years. Patients who had predominantly unilateral disease but evidence of one scar in the contralateral kidney were treated conservatively in the presence of moderate function on isotope renography and/or nonlateralized RVR. Of the five treated conservatively, three remain on antihypertensive drugs, while in two the hypertension has been intermittent and borderline, and has not required treatment at any time. Four nephrectomies were performed because of lateralization on renin studies in two, and poorly controlled hypertension in two. Three patients are now off treatment, and one continues on reduced dosage of antihypertensive drugs. Mean follow-up is 5 years. The four patients with bilateral scarring have conTable 2. Age at Presentation W i t h Hypertension of Patients With Scarred Kidneys Age (yr)

No.

0-4 4-8 8-12 12-16

0 6 16 11

Table 3. T r e a t m e n t and Outcome of 33 Children W i t h Scarred Kidneys, Subdivided According to the State of the Contralateral Kidney on Initial IVU State of Contralateral Kidney on Initial IVU and Treatment Requirement at Follow-up Normal/hypertrophied No antihypertensives Antihypertensives Single scar No antihypertensives Antihypertensives Multiple scars No antihypertensives Antihypertensives

Form of Management Nonoperative

Operative

5 1

14 0

2 3

3 1

0 1

0 3

tinued with antihypertensive drugs. Excision of a nonfunctioning kidney was performed in three patients with severe uncontrolled hypertension. Three had lateralization on RVR studies; all three showed an initial fall in hypertension following nephrectomy. In one patient, the requirement for antihypertensive drugs ceased but 6 years after operation, hypertension recurred and medication was resumed. The treatment and outcome of the remaining nine patients without scars on IVU is shown in Tables 4 and 5. DISCUSSION

This series differs from other reported pediatric series 1-3 with respect to the relatively small number of cases of renovascular hypertension and the large numbers of scarred kidneys. In the presence of a scarred kidney, hypertension remains a potential complication for many years; thus, whether the follow-up of children with urinary tract infection and scarred kidneys is undertaken by general practitioners, pediatricians, or pediatric surgeons, measurement of arterial blood pressure is necessary on a regular basis. In this series, there were seven children who had hypertension that was intermittent and not progressive. All had diastolic blood pressures of between 85 and 100 mmHg on several occasions and were, therefore, submitted to RVR studies. It may be that the partially ischemic segment(s) becomes totally nonfunctioning and the production of renin ceases, resulting in a cure of the hypertension. If hypertension develops, is persistent, and is associated with a minimally functioning kidney and a normal contralateral kidney, it is our experience that nephrectomy, whether partial or total, will be therapeutic, irrespective of the RVR result. The presence of a lateralizing RVR level is an additional indicator of the likelihood of surgery being beneficial, but nonlater-

TAYLOR, AZMY, AND YOUNG

230

Table 4. Treatment and Outcome of Children With Renovascular Hypertension

Etiology Renal artery aneurysm Generalized fibromuscular dysplasia Generalized fibromuscular dysplasia Aortic coarctation with renal artery stenosis Unilateral renal artery stenosis

Surgical Treatment

Outcome

Follow-up (yr)

Nephrectomy Nephrectomy

Death Antihypertensive required

Early postoperative 14

Nil

Antihypertensive required

14

Dacron tube and translocation of visceral vessels Nil

Antihypertensive required

9

No treatment required

7

Table 5. Treatment and Outcome of Four Children W i t h Hypertension Due to Miscellaneous Causes

Etiology Renal venous thrombosis Renal venous thrombosis Glomerulonephritis Angiomatous malformation

Surgical Treatment Nephrectomy (nonfunctioning kidney) Nil Nephrectomy (nonfunctioning kidney) Nil

alizing RVR does not preclude a good outcome. In one child in this series, an initially nontateratizing RVR lateralized 3 years later. In two cases where RVR was not lateralizing, it may be that a parenchymal segment was over-secreting renin, but that it was diluted beyond recognition at the level of the renal vein. Segmental RVR estimations can be helpful in accurate location of a hypersecreting segment, and thus in some cases it may be possible to excise the offending segment rather than perform a nephrectomy. 3 In the presence of bilateral scarring, this technique can be used to delineate the segments to be removed by bilateral partial nephrectomy, as advocated by Behrendt. 5 In this case, bilateral upper pole nephrectomy resulted in a normotensive child with normal renal function, but the follow-up of 10 months is short.

Outcome

Follow-up (yr)

No antihypertensives required No antihypertensives required Antihypertensives required Antihypertensive ceased after 3 yr. Normotensive and no treatment at follow-up

14 7 7 10

In those children with bilateral multiple scarring, surgery has a limited role and any early benefit will usually be short lived. However, in the presence of poorly controlled hypertension, removal of the most severely affected kidney may reduce antihypertensive requirements. CONCLUSIONS

(1) The risk of developing hypertension remains for many years in the presence of scarred kidneys. (2) Borderline hypertension may not always be progressive. (3) Nephrectomy is curative in the presence of a normal contralateral kidney. (4) Nephrectomy, although of some benefit in the short-term, is not helpful in the long-term in the presence of multiple scars in the contralateral kidney.

REFERENCES

1. Kaufman JM, Schiff M Jr, Stansel HC: Surgical treatment of renal hypertension in children. Br J Urol 113:681-685, 1974 2. Hendren HW, Kim SH, Herrin JT, et al: Surgically correctable hypertension of renal origin in childhood. Am J Surg 143:432-442, 1982 3. Parrot TS, Woodard JR, Trulock TS, et al: Segmental renal vein renins and partial nephrectomy for hypertension in children. J Urol 131:736-739, 1984

4. Alroomi LG, Murphy AV, Nelson CS, et al: Renal vein renin measurement and arteriography in the investigation and management of severe childhood hypertension. Clin Chim Acta 150:103109, 1985 5. Behrendt H, Bachmann H, Hartung R, et al: Hypertension due to refluxnephropathy. Normotension following bilateral partial nephrectomy. Urologe A 24: 84-86, 1985