Background: The study was aimed to analyze the pattern of bleeding throughout the kidney tissue after renal biopsy and evaluate its relationship with the onset of renal biopsy side effects by using directional power-Doppler sonography.
Patients: Eighty-five consecutive subjects with clinical evidence of renal disease underwent to percutaneous renal biopsy using directional power Doppler sonography. In each patient, the pattern of kidney hemorrhage immediately after the renal biopsy was evaluated.
Results: Fifty-seven patients, representing 67% of all biopsies performed, evidenced renal bleeding lasting 5.3+/-5.7 min; fifty-five patients, representing 65% of all biopsies, developed a post biopsy hematoma (x = 2.9+/-2.0 cm); 36% of patients developed a perirenal hematoma (x = 1.8+/-2.1 cm). A subcapsular hematoma was experienced by 45% of patients (x = 2.7+/-1.1 cm); 16% of these patients had a combined perirenal-subcapsular hematoma; 5% of hematomas were larger than 5 cm. Hematoma dimensions were related to the length of bleeding (r = 0.6331; p < 0.0001). Hemoglobin and hematocrit levels significantly reduced from 12.7+/-2.3 g/dL to 11.7+/-2.3 g/dL (-7%, p < 0.0001) and 37.6+/-6.5% to 35.4+/-6.5% (-6%, p < 0.0001) respectively, and such variations were related to the hematoma size (Delta Hb: r = -0.5171; p < 0.0001; Delta Htc: r = -0.3465; p < 0.0001).
Conclusions: This study demonstrates that directional power Doppler sonography allows medical personnel to clearly evidence all renal biopsy-related side effects and identify, through the evaluation of renal bleeding immediately after the kidney biopsy, those patients who will develop renal hematomas.