Correlation between glomerular size and long-term renal function in patients with substantial loss of renal mass

Focal segmental glomerulosclerosis and progressive renal failure have been reported in reduced renal mass models. However, these findings are not consistent across all species. Increased intracapillary pressure and chronic glomerular hyperfiltration have been shown to contribute to this progression. Studies also have shown that a strong correlation exists between higher glomerular size and the degree of glomerular sclerosis that develops following loss of functioning nephrons.

To evaluate the relationship between glomerular size and long-term renal function following massive renal mass removal we describe 9 patients with less than 50% renal mass. All patients had undergone initial nephrectomy followed by partial second nephrectomy, with 30% to 50% of the second kidney excised for localized tumor.

In 3 patients moderate to severe renal failure developed. Mean planar glomerular area (MPA) was 29.45 +/- 2.2 mm3 for all patients. Multivariate linear regression analysis demonstrated a significant association between MPA 30 mm3 or greater and increased serum creatinine. For patients with MPA 30 mm3 or greater the predicted delta creatinine was 2.43 mg/dl higher than that in patients with MPA less than 30 mm3 (p = 0.0028). Age was the only other covariate significantly associated with outcome in multivariate analysis.

Our data indicate an individual susceptibility toward developing renal failure after significant renal mass reduction. We suggest that patients with less than 50% renal mass and higher MPA are at greater risk for progressive renal failure. MPA may be used as a marker in high risk patients with substantial loss of renal mass to predict long-term renal function.