From the Guidelines
Angiotensin II receptor blockers (ARBs) primarily cause dilation of the efferent arteriole, while having less pronounced effects on the afferent arteriole, which can be beneficial in conditions like diabetic nephropathy and hypertension with proteinuria, as shown in studies such as 1.
Key Points
- ARBs block the action of angiotensin II at the AT1 receptor, which is predominantly responsible for efferent arteriolar constriction, as discussed in 2 and 3.
- By dilating the efferent arteriole, ARBs reduce intraglomerular pressure, which can be beneficial in conditions like diabetic nephropathy and hypertension with proteinuria, as noted in 1.
- However, this same action can potentially reduce glomerular filtration rate (GFR), especially in patients with renal artery stenosis or volume depletion, as warned in 4.
- Clinically, this means ARBs should be used cautiously in patients with compromised renal perfusion, and renal function should be monitored when initiating therapy, particularly in elderly patients or those with pre-existing renal impairment, as advised in 2 and 3.
Considerations
- The use of ARBs in patients with heart failure with reduced ejection fraction (HFrEF) is recommended to reduce morbidity and mortality, as stated in 2 and 3.
- ARBs are also recommended for patients with prior or current symptoms of chronic HFrEF who are intolerant to ACE inhibitors because of cough or angioedema, as noted in 2 and 3.
- The combination of an ACE inhibitor and an ARB can reduce proteinuria more than either agent alone, but may increase the risk of adverse events, as discussed in 5.
From the Research
Effect of ARB on Afferent and Efferent Arteries
- The effect of Angiotensin Receptor Blockers (ARBs) on afferent and efferent arteries is closely related to their role in blocking the renin-angiotensin system, which plays a crucial role in regulating blood pressure and renal function 6.
- ARBs have been shown to reduce morbidity and mortality associated with hypertension, heart failure, and chronic kidney disease by controlling hypertension and having a positive effect on renal function 6.
- The use of ARBs in patients with chronic kidney disease has been found to slow disease progression and reduce proteinuria, suggesting a renoprotective effect beyond blood pressure lowering 7.
- However, the evidence base for the use of ARBs in older adults with chronic kidney disease is limited, and more research is needed to determine their effectiveness in this population 8.
- In terms of specific effects on afferent and efferent arteries, ARBs have been found to inhibit the local tissue renin-angiotensin system, which can lead to less development of peritoneal fibrosis and a longer life for the peritoneal membrane in patients with chronic kidney disease 9.
- The combination of ARBs and angiotensin-converting enzyme inhibitors (ACEIs) may provide a more optimal blockade of the renin-angiotensin system, but more research is needed to determine the safety and efficacy of this combination 6, 7.
- A systematic review and meta-analysis found that exposure to ACEIs or ARBs after acute kidney injury was associated with lower risks of all-cause mortality, recurrent AKI, and progression to incident CKD, suggesting a potential benefit of ARBs in patients with acute kidney disease 10.