What is a normal estimated Glomerular Filtration Rate (eGFR) for a patient with a history of aortic dissection surgery and impaired renal function?

Normal eGFR Values

A normal eGFR is approximately 100-130 mL/min/1.73 m² for young men and 90-120 mL/min/1.73 m² for young women, with values varying by age, sex, and body size. 1

Standard Reference Values

• Young adults: Normal GFR ranges from 100-130 mL/min/1.73 m² in men and 90-120 mL/min/1.73 m² in women 1
• General population: A normal GFR is approximately 130 mL/min/1.73 m² for men and 120 mL/min/1.73 m² for women 1
• Age-related decline: GFR naturally declines at a mean rate of 0.75 mL/min per year with aging 1

Clinical Significance Thresholds

An eGFR ≥60 mL/min/1.73 m² is generally considered the threshold above which kidney function is not significantly impaired from a clinical standpoint. 1 However, this requires important context:

• eGFR ≥90 mL/min/1.73 m²: Classified as CKD Stage 1 only if kidney damage markers (albuminuria, hematuria, structural abnormalities) are present 1, 2
• eGFR 60-89 mL/min/1.73 m²: Classified as CKD Stage 2 only if kidney damage markers are present 1, 2
• eGFR <60 mL/min/1.73 m²: Defines CKD Stage 3 or worse, regardless of other markers, and correlates significantly with major cardiovascular adverse events 1, 2

Context for Post-Surgical Patients

For patients with a history of aortic dissection surgery and impaired renal function, understanding baseline normal values is critical for assessing recovery potential:

• Preoperative eGFR ≥60 mL/min/1.73 m²: Associated with minimal risk of chronic renal decline after aortic surgery 3
• Preoperative eGFR <60 mL/min/1.73 m²: Significantly increases risk of postoperative renal replacement therapy and chronic kidney disease progression 4, 5, 3
• Best cut-off for predicting postoperative complications: An eGFR of 60-70 mL/min/1.73 m² effectively predicts need for renal replacement therapy after aortic surgery 4, 5

Important Caveats

eGFR calculations can be inaccurate in non-steady-state conditions including immediately post-surgery, extremes of muscle mass, obesity, amputees, and diabetes with hyperfiltration 1. For post-aortic dissection patients:

• Creatinine values should be obtained at least 1 week after intervention to avoid transient effects from radiocontrast or periprocedural hydration 6
• Serial measurements are superior to single timepoint assessments for detecting stabilization or decline 6
• The CKD-EPI equation is more accurate than MDRD when eGFR >60 mL/min/1.73 m² and better predicts adverse outcomes 1