Plasma renin activity for monitoring vesicoureteric reflux therapy: mid-term observations

Role of endoscopic treatment of vesico-ureteric reflux in downgrading renin angiotensin system activation

OBJECTIVES

The objective of this study was to assess the role of endoscopic treatment of vesico-ureteric reflux (VUR) in downgrading renin angiotensin system (RAS) activation.

METHODS

Of 115 patients diagnosed and treated for VUR, 63 underwent hyaluronic acid/dextranomer (deflux) injection in a total of 99 ureteric moieties. Patients were monitored for urinary tract infection (UTI), glomerular filtration rate (GFR), plasma renin activity (PRA), renal scarring, persistence, or appearance of contra-lateral reflux.

RESULTS

Grade III VUR was most common (38%), and the most common cause of VUR was primary (60%). Analysis of patient characteristics at presentation revealed increased PRA in most cases (68%). Grade I VUR showed the most avid decrease in serum PRA levels after single injection. Serum PRA levels were sustainably low in patients of grade I and II VUR, whereas in patients of grade III values kept rising after reaching nadir. This increase in PRA levels correlated well with persistence of symptoms and reappearance of VUR in some patients.

CONCLUSION

PRA levels can be used as an indicator to initiate treatment of VUR. They can also be used for monitoring the progress of the disease and efficacy of the treatment given.

Effect of ipsilateral ureteric obstruction on contralateral kidney and role of renin angiotensin system blockade on renal recovery in experimentally induced unilateral ureteric obstruction

Aims:

To study, the effects of ipsilateral ureteric obstruction on contralateral kidney and the role of renin angiotensin system (RAS) blockade on renal recovery in experimentally induced unilateral ureteric obstruction.

Materials and Methods:

Unilateral upper ureteric obstruction was created in 96 adult Wistar rats that were reversed after pre-determined intervals. Losartan and Enalapril were given to different subgroups of rats following relief of obstruction.

Results:

The severity of dilatation on the contralateral kidney varied with duration of ipsilateral obstruction longer the duration more severe the dilatation. There is direct correlation between renal parenchymal damage, pelvi-ureteric junction (PUJ) fibrosis, inflammation and severity of pelvi-calyceal system dilatation of contralateral kidney with duration of ipsilateral PUJ obstruction.

Conclusions:

Considerable injury is also inflicted to the contralateral normal kidney while ipsilateral kidney remains obstructed. Use of RAS blocking drugs has been found to significantly improve renal recovery on the contralateral kidney. It can, thus, be postulated that contralateral renal parenchymal injury was mediated through activation of RAS.

Revised guidelines on management of antenatal hydronephrosis

Widespread antenatal screening has resulted in increased detection of anomalies of the kidneys and urinary tract. The present guidelines update the recommendations published in 2000. Antenatal hydronephrosis (ANH) is transient and resolves by the third trimester in almost one-half cases. The presence of oligohydramnios and additional renal or extrarenal anomalies suggests significant pathology. All patients with ANH should undergo postnatal ultrasonography; the intensity of subsequent evaluation depends on anteroposterior diameter (APD) of the renal pelvis and/or Society for Fetal Urology (SFU) grading. Patients with postnatal APD exceeding 10 mm and/or SFU grade 3-4 should be screened for upper or lower urinary tract obstruction and vesicoureteric reflux (VUR). Infants with VUR should receive antibiotic prophylaxis through the first year of life, and their parents counseled regarding the risk of urinary tract infections. The management of patients with pelviureteric junction or vesicoureteric junction obstruction depends on clinical features and results of sequential ultrasonography and radionuclide renography. Surgery is considered in patients with increasing renal pelvic APD and/or an obstructed renogram with differential renal function <35-40% or its subsequent decline. Further studies are necessary to clarify the role of prenatal intervention, frequency of follow-up investigations and indications for surgery in these patients.

Persistent renin-angiotensin system activation after anti-reflux surgery and its management

PURPOSE

To study renin-angiotensin system activation and the role of angiotensin-converting enzyme inhibition (ACE-I) after anti-reflux surgery.

MATERIAL AND METHODS

Thirty nine children underwent anti-reflux surgery for high grades of primary VUR. Plasma renin activity (PRA), urinary microalbumin, renal scars, split renal function (SRF), glomerular filtration rate (GFR), serum creatinine, blood pressure and episodes of breakthrough urinary tract infection were monitored in the early (5.9 ± 3.9; range 3-9 months) and late (27.1 ± 6.5; range 15-36 months) postoperative phase, before and after therapy with ACE-I (mean period 13.6 ± 2.5; range 10-24 months).

RESULTS

The early postoperative improvement in renal parameters (rise in SRF and GFR by 11.2% and 7.3%, respectively, and fall in PRA by 68.8%), was not sustained subsequently (minimal improvement in SRF, 7.4%, and GFR, 0.14%, was accompanied by a rise in PRA by 92.3%). After ACE-I therapy, improvement was noted in SRF and GFR by 0.5% and 7.5%, respectively, and there was a fall in urinary microalbumin by 52.3%.

CONCLUSIONS

Significant down regulation of rennin-angiotensin system activation and the accompanying improvement in renal function seen early after surgery is not sustained during follow up. ACE-I aids renal recovery.