ACEi causing a drop in GFR (10)

This 72 year old lady has a previous medical history of hypertension, gout (thought to be thiazide induced) and acute renal failure secondary to gastroenteritis (12 years ago). She is on allopurinol, atorvastatin & 30mg of lisinopril.

3 weeks ago, I noted her eGFR had fallen to 50, with potassium of 5.3. Her U&Es were normal 3 months previously.  The specimen was repeated a week later, and showed a drop in eGFR to 37, with a potassium of 5.5. I asked her to stop her ACEI immediately, which she did, with a eGFR back up to 55 a week later.  Subsequently she restarted her lisinopril again as she felt “headachy” without it.  Unsurprisingly her eGFR dropped again to 45 with a potassium of 5.4. I have taken her off her lisinopril and asked her not to restart it again.

During this whole episode she has been totally well. Her blood pressure today was 132/70 (though it had been higher than this previously), with a normal abdominal examination, no urinary symptoms at all, and no blood or protein in her urine (though it was strongly positive for nitrites so I have sent an MSSU).

Is it possible she has renal artery stenosis or is there another explanation for her drop in renal function? I have put her on amlodipine temporarily although I believe this delivered suboptimal BP control in the past. Should I undertake any investigations for this lady?

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The long-held belief that a rise in creatinine with an ACEi equals a renal artery stenosis has probably been overstated over the years. The answer is “yes” – she may have, but our renal blood flow is partly dependent on angiotensin and changes whenever we use an ACEi.

The main points are that;
a) Intervention to renal artery lesions are now discredited except for all the most severe ones, which she hasn’t got.
b) She is very well, her creatinine is normal, her eGFR is OKish for her age, urinalysis is normal and her BP is excellent.

I would do nothing more than you are currently doing. I would accept eGFRs in the 40+ – for her if stable, and I would treat her as a straightforward hypertensive.


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