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The final paragraph of your research update article on renal function after renin-angiotensin system blockade is misleading.
The findings are striking but not unexpected. Small vessel renovascular disease (ischaemic nephropathy) is a common manifestation of generalised vascular disease. The decrease in filtration after an ACEI (or ARB) is simply a reflection of the inability of the renal glomerular microcirculation to autoregulate filtration pressure. Either the glomerular haemodynamic pressure is being maintained by tonic ACE mediated constriction of the efferent arteriole (which is abolished) and/or the inflow is prevented from increasing by increased vascular compliance/obstruction to flow due to vascular disease. As such then I would argue that the increase in creatinine (decrease in eGFR) is simply another marker of the severity of vascular disease. Hence it will be associated with poorer outcomes. This effect does not prompt consideration of the risks of continuing treatment but rather points to a subgroup of patients who could be targeted for more intensive management of vascular risk. Simply to discontinue ACEI (or ARB) is to miss the point.