From the Guidelines
ACE inhibitors are contraindicated in bilateral renal artery stenosis because they can cause acute kidney injury and potentially lead to kidney failure in these patients. In bilateral renal artery stenosis, blood flow to both kidneys is already reduced due to narrowing of the renal arteries. The kidneys respond to this decreased perfusion by activating the renin-angiotensin-aldosterone system (RAAS), which causes vasoconstriction of the efferent arterioles, helping to maintain glomerular filtration pressure despite reduced blood flow. When ACE inhibitors are administered, they block this compensatory mechanism by preventing the formation of angiotensin II, which leads to dilation of the efferent arterioles. This dilation reduces the pressure gradient across the glomerulus, causing a significant drop in glomerular filtration rate and potentially precipitating acute kidney injury, as noted in the study by 1.
Some key points to consider in the management of patients with bilateral renal artery stenosis include:
- The use of ACE inhibitors may be considered in bilateral severe RAS and in the case of stenosis in a single functioning kidney, if well-tolerated and under close monitoring, according to the 2017 ESC guidelines 1.
- Alternative antihypertensive medications such as calcium channel blockers or beta-blockers should be used instead for patients with known or suspected bilateral renal artery stenosis.
- The risk of ACE inhibitor–induced acute renal failure (ARF) is higher in patients with chronic renal insufficiency of any cause than in patients with normal renal function, as discussed in the study by 1.
- Patients with unilateral renal artery stenosis may tolerate ACE inhibitors because the unaffected kidney can compensate, but with bilateral stenosis, this compensatory ability is lost.
Overall, the use of ACE inhibitors in patients with bilateral renal artery stenosis requires careful consideration of the potential risks and benefits, and alternative treatments should be considered to minimize the risk of acute kidney injury.
From the Research
Mechanism of Contraindication
- ACE inhibitors are contraindicated in patients with bilateral renal artery stenosis due to the risk of azotemia resulting from preferential efferent arteriolar vasodilation in the renal glomerulus caused by inhibition of angiotensin II 2, 3, 4, 5.
- The use of ACE inhibitors in renovascular hypertension remains controversial, as ACE inhibition can interfere with the autoregulation of glomerular filtration rate (GFR) mediated by angiotensin II, leading to deterioration of renal function, especially in patients with bilateral renal artery stenosis or stenosis of a solitary kidney 4, 5.
Clinical Implications
- Bilateral renal artery stenosis, or a unilateral stenosis in a patient with only one kidney, is an absolute contraindication to ACE inhibition 3.
- Acute renal failure is a common consequence of ACE inhibitor therapy in patients with bilateral renal artery stenosis, or renal artery stenosis to a single functioning kidney 5, 6.
- The effects of ACE inhibitors on renal hemodynamics vary widely depending on the preexisting physiologic and pathologic state of the kidneys 4.
Special Considerations
- Patients with renal artery stenosis who can derive survival benefit from ACE inhibition may not receive ACEI therapy due to the risk of azotemia 2.
- However, some studies suggest that patients with bilateral renal artery stenoses that have been successfully revascularized using renal stenting may be safely treated with long-term ACEI therapy 2.