How do efferent or serial resistance and Central Venous Pressure (CVP) affect glomerular perfusion pressure?

From the Guidelines

Efferent resistance, afferent resistance, and central venous pressure (CVP) all significantly impact glomerular perfusion pressure, with elevated CVP reducing the pressure gradient across the glomerulus and diminishing filtration, as evidenced by the most recent study in 2024 1.

Key Factors Affecting Glomerular Perfusion Pressure

• Efferent arteriolar resistance: increases glomerular hydrostatic pressure and enhances filtration by preventing blood from leaving the glomerulus easily
• Afferent arteriolar resistance: reduces blood flow into the glomerulus, decreasing filtration pressure
• Central venous pressure (CVP): affects glomerular perfusion by influencing renal venous pressure; elevated CVP increases renal venous pressure, reducing the pressure gradient across the glomerulus and diminishing filtration

Clinical Implications

• Diuretics can improve kidney function in heart failure by reducing CVP, as supported by the 2024 study 1
• The net glomerular filtration pressure depends on the balance between these factors, with efferent constriction generally increasing filtration while afferent constriction and elevated CVP decrease it
• Understanding this relationship is crucial in managing patients with heart failure and kidney dysfunction, as highlighted in the 2018 study 1 and the 2024 study 1

Pathophysiological Mechanisms

• Elevated CVP can lead to renal venous congestion, reducing glomerular blood flow and filtration pressure, as described in the 2018 study 1
• The use of ACE inhibitors or angiotensin receptor-blocking medications in patients with bilateral renal artery stenosis or stenosis to a solitary kidney can result in acute renal failure, as explained in the 2006 study 1
• Maintaining adequate trans-kidney perfusion pressure (TKPP) is essential in managing kidney dysfunction in advanced heart failure, as emphasized in the 2024 study 1

From the Research

Efferent or Serial Resistance and Glomerular Perfusion Pressure

• Efferent arteriolar resistance plays a crucial role in maintaining glomerular filtration rate (GFR) despite reduced renal perfusion pressure 2
• The ratio of preglomerular to postglomerular resistance is reduced in ischemic kidneys, helping to maintain GFR 2
• In hypertension, the glomerular capillary pressure tends to increase due to a greater reduction in afferent arteriolar resistance compared to efferent resistance 3

Central Venous Pressure (CVP) and Glomerular Perfusion Pressure

• Increased CVP is associated with impaired renal function and mortality in patients with cardiovascular disease 4
• CVP is inversely related to estimated glomerular filtration rate (eGFR) 4
• In patients with acute heart failure, combined low systolic blood pressure and high CVP predispose to lower eGFR 5
• However, lower CVP may also be associated with short-term worsening renal function 5

Relationship Between CVP, Efferent Resistance, and Glomerular Perfusion Pressure

• The relationship between CVP, efferent resistance, and glomerular perfusion pressure is complex and influenced by various factors, including renal perfusion pressure, afferent resistance, and cardiac index 4, 6
• A model to estimate intraglomerular pressure using invasive renal arterial pressure and flow velocity measurements has been developed, which may help to better understand the relationship between CVP, efferent resistance, and glomerular perfusion pressure 6