The investigation of renovascular hypertension in children: the accuracy of radio-isotopes in detecting renovascular disease.

Renovascular disease is an important cause of hypertension in children because it is potentially treatable by surgical or angioplasty techniques. The aim of this study was to assess the accuracy of radio-isotopes (DMSA, DTPA and MAG3) combined with the angiotensin converting enzyme inhibitor, captopril, in detecting children with renovascular hypertension. We retrospectively reviewed the ultrasound and pre- and post-captopril radionuclide studies (either DMSA and/or DPTA and/or MAG3) of children with sustained hypertension investigated at our institution. Renal angiography was used as the 'reference technique'. Thirty-nine children, over a period of 10 years, were evaluated: 17 (44%) children had renovascular disease that involved the proximal three divisions of the renal arteries, some of which were amenable to treatment. The overall sensitivity, specificity, positive predictive value and negative predictive value for detecting such renovascular disease, as assessed by changes between pre- and post-captopril radio-isotope studies, were disappointing at 59%, 68%, 59% and 68%, respectively. When considering only abnormalities in post-captopril studies, these indices were 82%, 41%, 52% and 75%, respectively. Three children with potentially treatable renovascular disease were not identified on the captopril studies. We conclude that renal angiography should remain the 'reference technique' in identifying children suspected of renovascular hypertension.