Blood pressure changes after extracorporeal shock wave nephrolithotripsy: prediction by intrarenal resistive index.

In order to identify a high-risk group for the development of arterial hypertension after extracorporeal shock wave nephrolithotripsy (ESWL), we correlated the increase in renovascular resistance induced by ESWL in 79 normotensive patients with changes in arterial blood pressure occurring 20 (+/- 3) months after therapy. Renal vascular resistance was measured as resistive index (RI) by duplex Doppler sonography in both kidneys. Mean RI before treatment was 0.620 +/- 0.035 (SD). After treatment, we observed a significant and age-dependent increase in the RI in the treated kidney to 0.673 +/- 0.06. Of the patients with a post-ESWL RI > 0.690, 39% developed hypertension. Posttherapy RI values surpassing 0.690 showed a 0.8 sensitivity and a 0.7 specificity in predicting arterial hypertension. Intrarenal Doppler ultrasound (US) is useful to find the high-risk group for arterial hypertension after ESWL.