Renal haemorrhage risk after extracorporeal shockwave lithotripsy: results from the Japanese Diagnosis Procedure...

To assess clinical and mechanical risk factors of clinically significant renal haemorrhage after extracorporeal shock wave lithotripsy (ESWL).

Patient data were extracted from the Diagnosis Procedure Combination (DPC) database from 6 months per each year, 2006-2008. The availability of lithotripters in each hospital was identified. We performed logistic regression analysis, which included the generator type (electrohydraulic, electromagnetic or piezoelectric), age, gender, laterality of stones (right, left or uncertain), location of stones (kidney, ureter or uncertain), total number of treatment sessions, anaesthesia and hospital volume (HV), focal size (greater or less than 400 mm(3)) and F2 angle (greater or less than 70°). Renal haemorrhage events were identified within the database.

Overall, 81 renal haemorrhage events in 26,969 patients (32,476 ESWL sessions) at 482 hospitals with 38 lithotripter models were identified. The incidence of events was 0.50% with renal stones and 0.14% with ureter stones. Specifications of 34 lithotripter models were available. Use of piezoelectric lithotripters (vs electromagnettic, OR 0.13, P = 0.044) and high HV (≥140/year, vs ≤70/year, OR 0.49, P = 0.012) significantly decreased the risk of renal haemorrhage events. Age, gender, focal size and F2 angle did not show statistical significance.

There is a low incidence of renal haemorrhage after ESWL. The less invasive nature of piezoelectric lithotripters and an inverse volume-outcome relationship with ESWL procedures was revealed. Age, focal size and F2 angle do not appear to have a significant impact on renal haemorrhage.