Does a nephrectomy (removal of a kidney) reduce Glomerular Filtration Rate (GFR)?

From the Guidelines

Yes, a nephrectomy (removal of a kidney) does reduce Glomerular Filtration Rate (GFR). When one kidney is removed, the immediate effect is approximately a 50% reduction in total GFR since each kidney normally contributes about half of the total filtering capacity. However, the remaining kidney typically undergoes compensatory hypertrophy and hyperfiltration, increasing its function by about 20-40% over time. This means that after adaptation, a person with one kidney will usually have a GFR of approximately 60-80% of their pre-nephrectomy value.

Key Considerations

• The reduction in GFR after nephrectomy is a significant consideration for patient management and outcomes, as it can impact the risk of chronic kidney disease and end-stage renal disease 1.
• The type of nephrectomy, whether partial or radical, can influence the extent of GFR reduction, with partial nephrectomy (PN) leading to more favorable short- and long-term GFR compared with radical nephrectomy 1.
• Post-nephrectomy care should focus on preserving renal function through regular monitoring, blood pressure control, avoidance of nephrotoxic medications, and adherence to a kidney-friendly diet.

Evidence-Based Recommendations

• Patients who have undergone nephrectomy should be closely monitored for signs of renal dysfunction and managed accordingly to prevent further decline in GFR 1.
• The use of angiotensin-converting enzyme inhibitors (ACE inhibitors) or angiotensin receptor blockers (ARBs) can help slow the progression of kidney disease in patients with reduced GFR, although the evidence is more robust for their use in patients with chronic kidney disease rather than post-nephrectomy patients specifically 1.
• Maintaining good hydration, controlling blood pressure, and following a kidney-friendly diet are crucial for preserving the function of the remaining kidney after nephrectomy.

Clinical Implications

• The management of patients post-nephrectomy requires a multidisciplinary approach, including regular follow-up with a nephrologist, to monitor kidney function and adjust treatment as necessary.
• Patients should be educated on the importance of lifestyle modifications, such as diet and hydration, in preserving kidney function.
• The potential for compensatory hypertrophy and hyperfiltration in the remaining kidney underscores the importance of close monitoring and management to optimize outcomes.

From the Research

Nephrectomy and GFR

• A nephrectomy, which is the removal of a kidney, can impact Glomerular Filtration Rate (GFR) in various ways, depending on the type of nephrectomy and individual patient factors 2, 3, 4.
• Studies have shown that after a partial nephrectomy, the GFR can decline by approximately 20% in the operated kidney, and by about 10% in terms of global renal function for patients with two kidneys 3.
• Factors that can affect the proportional GFR after minimally invasive partial nephrectomy include patient, tumor, and operative characteristics, such as preoperative proportional GFR, procedure approach, ischemia time, and estimated blood loss 5.
• The use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) preoperatively has been evaluated in relation to changes in estimated GFR after robotic-assisted partial nephrectomy, with no significant association found 6.
• Predicting GFR after radical nephrectomy is important, and a model based on split renal function and renal functional compensation has been proposed as a simple and accurate approach to predict new-baseline-GFR after radical nephrectomy 4.

Impact on GFR

• The decline in GFR after partial nephrectomy can be due to incomplete recovery from the ischemic insult or loss of nephron mass related to parenchymal excision or collateral damage during reconstruction 3.
• Compensatory hypertrophy in the contralateral kidney after partial nephrectomy in adults is marginal, and the decline in global renal function can vary based on tumor size and location 3.
• Irreversible ischemic injury can be minimized by pharmacological intervention or surgical approaches such as hypothermia, limited warm ischemia, or zero or segmental ischemia 3.
• Excessive loss of nephron mass can be minimized by improved preoperative or intraoperative imaging, use of a bloodless field, enucleation, and vascular microdissection 3.