Are we estimating the adverse effects of shock-wave lithotripsy on a faulty scale?

The adverse effect of shock-wave lithotripsy (SWL) for renal stones on blood pressure is currently defined as its post-treatment increase. On the contrary, we hypothesize that even mild, unilateral renal obstruction initiates an increase in blood pressure. Then, in absence of treatment-induced injury, the stone removal should decrease the blood pressure. We derived the formula to assess the expected change in the mean arterial pressure following relief of renal obstruction without affecting the kidney functions. The predictions were well replicated in the cohort of patients with renal stone treated with parenchyma-saving open surgery, with 6.4 mmHg decrease at 3 months. On the contrary, in SWL cohort, instead of the expected 4.7 mmHg decrease, the blood pressure was unchanged. In conclusion, the absence of decrease in blood pressure is a very common adverse effect of SWL, leading to an epidemiologically significant increase in the risk of arterial vascular events.