Monitoring renal function in hypertension

Case 1

A 64 year old woman was referred to a hypertension clinic with a blood pressure of 180/110 mm Hg. Her biochemical profile was normal (serum creatinine concentration 102 µmol/l, urea 6.4 mmol/l, potassium 4.2 mmol/l, sodium 139 mmol/l). Treatment started with amlodipine 5 mg, and when she was reviewed, six weeks later, her blood pressure was 165/95 mm Hg. Perindopril 4 mg was added, and one week later her blood pressure was 144/70 mm Hg. However, her renal function showed some deterioration, with slight rises in serum creatinine concentration (110 µmol/l) and urea concentration (9.3 mmol/l). A month later the patient's blood pressure control remained good (140/70 mm Hg), but there was further deterioration in renal function (creatinine of 143 µmol/l, urea 10.4 mmol/l). A further month later, she was normotensive (139/71 mm Hg) with no further change in renal function (creatinine 143 µmol/l, urea 11 mmol/l).

In view of the deterioration in her renal function, she was investigated with a renal ultrasound scan followed by enhanced renal magnetic resonance angiogram. A short tight stenosis of the left renal artery was diagnosed. A nuclear medicine renal scan showed that …