Evaluation of hematochemical parameters and renal echography after ESWL treatment with Tripter X1 was done on the first 95 patients treated and for whom we had a longer than 3-month follow-up. Creatinine phosphokinase values showed an increase in 24 patients. 12 patients demonstrated an increase in amylasemia. Echographic checks performed the day after treatment revealed the presence of perirenal lesions in 3 cases. As far as amylasemia is concerned, only 1 patient was treated with aprotinin. One of the patients who developed perirenal hematoma had hypertension; another was following an antiaggregant therapy that was temporarily suspended.