Evaluation and treatment of renovascular hypertension and ischaemic renal disease

Hypertension in the presence of renal artery stenosis may not necessarily be renovascular hypertension. The two conditions may simply co-exist. Some features of renovascular hypertension include: a worse prognosis than essential hypertension, less amenable to drug treatment, a greater risk of dose-dependent: side effects, a higher risk of progression to accelerated hypertension and it may result in irreversible ischaemic failure of the affected kidney. Renovascular hypertension is usually symptomless, while hypertension that is difficult to control with antihypertensive therapy is probably the best indication as to whether further diagnostic evaluation is indicated. A clue is a rise in the plasma creatinine concentration following the introduction of an angiotensin converting enzyme inhibitor (ACEI). Renal artery stenosis may be present in up to 30% of drug resistant hypertensive patients. Arteriosclerotic renovascular disease is an increasingly important cause of renal failure. In this institution from 1 January 1988 to 31 December 1993, 491 patients were referred with a plasma creatinine of greater than or equal to 0.30 mmol/L. Hypertension/nephrosclerosis/renal artery stenosis was the diagnosis in 75 of 372 (20%) of those patients who had chronic renal failure. Of the last 427 patients entering our renal replacement programme, 23 were due to hypertensive nephrosclerosis and an additional five due to renal artery stenosis (6.6% of the total). Functional diagnostic tests for renovascular hypertension such as rapid sequence intravenous urography have now been superseded by the captopril challenge test and in particular scintigraphy following captopril provocation. Tests of prediction as to whether correction of a demonstrated renal artery stenosis will lead to an improvement in the blood pressure include renal vein renin estimations and scintigraphy. The key diagnostic procedure is renal angiography. The approaches to management primarily include appropriate antihypertensive therapy, while there is an increasing place for percutaneous transluminal angioplasty, with or without stenting of an occluding lesion. There is still a small place for corrective surgery. Renal ischaemia due to atherosclerotic renovascular disease is becoming an increasing problem in nephrology. Treatment should be directed at presenting or even restoring renal function.