Hypertension in children with poorly functioning unilateral kidneys: predictors of resolution after nephrectomy

OBJECTIVE To identify the outcome of nephrectomy and predictors of hypertension (HTN) resolution in children with poorly functioning unilateral kidneys (differential renal function, DRF of < 15%), as concurrent HTN is often an indication for nephrectomy. PATIENTS AND METHODS Over a 7.5-year period, a single centre retrospective analysis of 89 children with unilateral nonfunctioning/poorly functioning kidney who underwent nephrectomy was conducted. Preoperative HTN was present in 18 children (20.2%). The childrens' characteristics (age, sex, body mass index, pathology, side), cause of nonfunction, diagnostics including preoperative proteinuria (dipstick) and DRF (nuclear scan), pathological features of specimen and follow-up were recorded. RESULTS The mean (median; range) age at nephrectomy was 6.8 (5; 0.333-14) years with a mean (median; range) follow-up of 2.4 (3; 0.083-5.5) years. The mean (median; range) DRF was 6.5 (1; 0-15)%. Twelve of 18 children (67%) resolved their HTN. Age at nephrectomy, sex, side of nonfunctioning kidney and surgical approach (78% laparoscopic nephrectomy) did not correlate with HTN resolution. Persistence of HTN seemed to correlate with residual function of more than a DRF threshold of 5% (P = 0.05), the presence of preoperative qualitative proteinuria by dipstick (P = 0.03) and inflammation on pathology. CONCLUSIONS HTN resolved after nephrectomy for poorly functioning unilateral kidney in most of the children. Persistence of HTN is probably multifactorial. Ipsilateral residual function before nephrectomy, preoperative proteinuria and pathological features of nephrectomy specimen may serve as clinically useful markers for outcome prediction.