Kidney Histopathology Features of Suspected Intra-Kidney Venous Thromboembolism in Patients with Primary Glomerulonephritis

Abstract

<b><i>Introduction:</i></b> Renal vein thromboembolism is a severe complication of nephrotic syndrome. Small thrombus in the intra-kidney venous system cannot be recognized by ultrasonography. The current study was to investigate the kidney pathological features of intra-kidney venous thrombus and their values in clinical practice. <b><i>Methods:</i></b> Kidney pathological features of glomerular capillary dilatation and congestion, peritubular capillary dilatation and congestion, and intraglomerular neutrophil infiltration were screened and scored during kidney biopsy information interpretation. Eighty-four consecutive patients with these features and primary glomerulonephritis were analyzed, comparing to another 84 control patients without these features who were matched according to the pathological types of glomerulonephritis. <b><i>Results:</i></b> In the patients with pathological features of suspected intra-kidney venous thrombus, the levels of proteinuria (5.2 vs. 3.2 g/24 h, <i>p</i> = 0.005), serum creatinine (80.9 vs. 71.2 μmol/L, <i>p</i> &#x3c; 0.001), platelet count (274.0 vs. 254.5 ×10⁹/L, <i>p</i> = 0.020), D-dimer (0.2 vs. 0.2 mg/L, <i>p</i> = 0.002), and fibrin degradation products (1.9 vs. 1.0 mg/L, <i>p</i> = 0.003) were significantly higher than those in control patients. The levels of serum albumin (24.2 vs. 28.6 g/L, <i>p</i> = 0.003) and eGFR (92.1 vs. 103.9 mL/min/1.73 m², <i>p</i> &#x3c; 0.001) were significantly lower. The scores of these pathological features were positively correlated with the levels of D-dimer (r = 0.21, <i>p</i> = 0.05). During follow-up, 9 (10.7%) patients with pathological features of suspected intra-kidney venous thrombus developed venous thromboembolism, which was significantly more than that of control patients (0%, <i>p</i> = 0.006). <b><i>Conclusions:</i></b> Kidney pathological features could indicate intra-kidney venous thromboembolism, and their scores represent the possibility of thrombus. The notice of these features may provide clinical alerts for venous thromboembolism possibility.