Objective: Although conventional renal biopsy is a useful procedure in determining renal histological diagnosis and guiding treatment, bleeding is a major complication even with experienced nephrologists. A new method of renal biopsy, the real-time ultrasound guided spring-loaded gun biopsy, has been developed. Some reports show less bleeding with this new method, but it is also more expensive. Bleeding in conventional renal biopsy in Songklanagarind Hospital has not been studied before. The purpose of this study was to find the extent of clinical bleeding of the conventional renal biopsy, to look at whether the new method of renal biopsy would be appropriate, and to identify the risk factors involved.
Material and Methods: Data were collected from medical records. Minor bleeding was defined as asymptomatic gross hematuria. Major bleeding was defined as bleeding that had clinical significance such as being associated with intense pain, needing a blood transfusion or requiring an intervention to stop the bleeding. A P-value less than 0.05 was considered to be statistically significant.
Results: Bleeding occurred in 13.4% of cases. Most were of a minor nature (88.8%). The major bleeding rate was 1.5%. These cases were gross hematurias that required blood transfusion and perirenal hematoma that had intense pain in 1% and 0.5% respectively. All stopped spontaneously and no cases needed intervention or died. There was a significantly lower hematocrit and number of total glomeruli in the bleeding group than in the no-bleeding group (28.9 ± 7.66 vs. 33.1 ± 8.5, p = 0.02 and 14.0 ± 11.1 vs. 20.3 ± 13.3, p = 0.02 respectively). Female patients tended to have a higher rate of bleeding than male patients (17% and 8% respectively, p = 0.062). Multivariate analysis indicated that an increase of every 1 total glomeruli decreased, and pre-biopsy hematocrit lower than 25% increased, the risk of bleeding (odds ratio 0.96 and 2.76 respectively).
Conclusion: There was a high bleeding rate, but most cases were minor. The major bleeding had a low clinical impact on patient morbidity and mortality. The associated factors were lower hematocrit and improper renal biopsy technique.