What is the variability in blood pressure in renal (kidney) arterioles and arteries after the glomerular efferent arteriole?

From the Guidelines

The pressure in renal arterioles and arteries after the glomerular efferent arteriole shows significant variability, with pressure drops substantially as blood moves from the afferent arteriole through the glomerulus and into the efferent arteriole, and continues to decrease progressively through the peritubular capillaries and into the venous system. The pressure gradient is essential for proper kidney function, facilitating glomerular filtration at the higher-pressure glomerular capillaries while enabling fluid reabsorption at the lower-pressure peritubular capillaries. Some key points to consider include:

• Pressure in the afferent arteriole is approximately 60-80 mmHg, in the efferent arteriole is about 35-40 mmHg, in the peritubular capillaries is approximately 10-15 mmHg, and in the venous system is about 5-10 mmHg 1.
• The variability in pressure is regulated by vasoconstriction or vasodilation of the afferent and efferent arterioles, which helps maintain appropriate filtration pressure despite changes in systemic blood pressure.
• This autoregulatory mechanism involves multiple factors including the renin-angiotensin-aldosterone system, tubuloglomerular feedback, and myogenic responses to ensure stable renal blood flow and glomerular filtration rate across a range of physiological conditions.
• The use of ACE inhibitors or angiotensin II receptor blockers can cause acute renal failure in patients with bilateral renal artery stenoses or stenosis to a solitary kidney, by decreasing transglomerular hydrostatic pressure and thus glomerular filtration rate 1.
• The pathophysiology that results from renal artery stenosis is mediated by the degree of renal blood flow impairment, and can cause a renin-mediated form of hypertension, although renin increases may be moderated in the chronic phase of renal hypertension 1.

From the Research

Variability in Pressure in Renal Arterioles and Arteries

The variability in pressure in renal arterioles and arteries post glomerular efferent arteriole is influenced by several factors, including:

• The myogenic response of the renal afferent arteriole, which helps to protect the glomerulus from excessive pressure 2
• The role of the renin-angiotensin system in regulating glomerular filtration, including the effects of angiotensin II on afferent and efferent arterioles 3
• The use of certain medications, such as calcium antagonists, angiotensin-converting enzyme inhibitors, and cyclosporine, which can have direct effects on the preglomerular and postglomerular vessels 4
• The impact of systemic blood pressure on the glomerulus, including the effects of hypertension and diabetes mellitus on kidney function 4, 5

Factors Affecting Pressure Variability

Some key factors that affect pressure variability in renal arterioles and arteries include:

• Systolic blood pressure, which can have a damaging effect on the glomerulus 2
• The diameter of the afferent and efferent arterioles, which can be influenced by various medications and conditions 4, 5
• The glomerular filtration rate, which is determined by the balance between glomerular pressure and tubular oxygen supply 5
• The role of vasodilator prostaglandins, which can help to sustain glomerular filtration in response to decreases in renal plasma flow 3