BERKELEY, CA (UroToday.com) - In a previous study, we found that short-term renal function loss is proved to be temporary and reversible provided that there is no post-SWL obstruction that would lead to chronic reduction of renal function.

In the current study, there were100 participating patients, included according to specific inclusion and exclusion criteria to alleviate any other intervening factors other than SWL, impacting renal function. We not only measured the changes in the treated kidney, but we also documented the changes in the other normal kidney. Isolated measurements of GFR and clearance of each side show any impact on either side, which may not appear using the split function. All of our treated stones were radio-opaque to avoid renal damage related to difficult localization and hitting the parenchyma, a technical difficulty that is usually encountered during the disintegration of faint or radiolucent stones.

We found that there is no significant impact on different parameters of renogram for the treated renal unit or on the contra-lateral non-treated one after nearly five years of follow up - even after stratifying our patients into different groups based on BMI or the type of lithotripter.

We believe that judicious use of SWL by an expert urologist, and with proper selection of patients, will save the unnecessary extra sessions and out-of-focus renal trauma. Under these circumstances, SWL will exhibit a degree of safety and all other secondary parameters like BMI and type of lithotripter will have no significant effect on the outcome. Close post-SWL follow up and urgent management of any obstruction are essential to avoid negatively impacting renal function.

Hypertension following SWL has been an ongoing controversy since the original reports of acute onset hypertension following SWL were published in the mid to late 1980s. Subsequent studies with intermediate follow-up (less than 5 years), however, did not demonstrate these effects on blood pressure. In our study we compared pre-SWL and post-SWL BP and used data from the largest national study of hypertension for the incidence of new onset hypertension in a normal Egyptian population of similar demographic data as a control group. Based on findings from a national probability survey of 6,733 adults 25 years old or older (mean age 45.6 years), the report from the Egyptian National Hypertension Project indicated that the overall prevalence of hypertension in Egypt is estimated to be 26.3% - a much higher number than the incidence in our study group and sufficient to confirm our conclusion that hypertension is not linked to SWL.

Moreover, several epidemiological studies have suggested an association between nephrolithiasis and hypertension. The reported magnitude of the relationship between stones and BP has varied greatly among studies. A reason for this heterogeneity is the existence of subgroups at particular risk for increased BP in the presence of nephrolithiasis, such as those with hypercalciuria and high BMI, and female stone formers. Thus, we must focus our attention on treating these subgroups of patients with judicious application of SWL.

The effect of SWL on blood pressure could be a result of multiple factors - mostly related to the patient status, medical and surgical history, stone burden and infection, and renal sufficiency at time of SWL. These extraneous factors should be mitigated in order to permit the test of the sole effect of SWL on renal function. Misuse of SWL, and widening of patient range treated, may greatly contribute to the published results that correlate SWL with the reduction of renal function and the increase in incidence of hypertension.

Written by
Khaled Z. Sheir, MD, as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

Prospective Study of the Long-Term Effects of Shock Wave Lithotripsy on Renal Function and Blood Pressure - Abstract

UroToday.com Stone Disease Section

read other Beyond The Abstract submissions

More Information about Beyond the Abstract

Please log-in or register in order to submit comments.

Powered by AkoComment!