Blood pressure, angiotensin-converting enzyme (ACE) inhibitors, and the kidney.

Angiotensin II plays an important role in the kidney by regulating renal flow, glomerular filtration rate, mesangial cell function, and sodium reabsorption. Blockade of the renin-angiotensin system has powerful effects on kidney function. Studies in animal models of renal failure suggest that converting enzyme inhibitors slow down the inevitable progression of the renal failure. This could be in part due to their effect on reducing glomerular pressure or by reducing glomerular hypertrophy. In patients with malignant hypertension, diabetic nephropathy, and other causes of renal failure, preliminary evidence suggests that lowering the blood pressure with angiotensin-converting enzyme (ACE) inhibitors may possibly carry some other benefits compared with other blood pressure lowering regimens. However, single drug therapy is rarely sufficient to control blood pressure in these patients. Further properly controlled randomized trials should give a clear indication of whether any particular class of drug has any advantage in slowing down the progressive renal impairment for a given lowering of blood pressure. In patients with renovascular hypertension ACE inhibitors are effective drugs in lowering blood pressure. However, in certain settings they may cause a reversible decline in renal function.