Connors BA et al, 2016: Using 300 Pretreatment Shock Waves In A Voltage Ramping Protocol Can Significantly Reduce Tissue Injury During Extracorporeal Shock Wave Lithotripsy.
Connors BA, Evan AP, Handa RK, Blomgren PM, Johnson CD, Liu Z, Lingeman JE.
Department of Anatomy and Cell Biology, Indiana University School of Medicine , Indianapolis, Indiana.
Department of Biostatistics, Indiana University Schools of Public Health and Medicine , Indianapolis, Indiana.
Methodist Hospital Institute for Kidney Stone Disease , Indianapolis, Indiana.
Abstract
Purpose: Pretreating a pig kidney with 500 low energy shock waves (SWs) before delivering a clinical dose of SWs (2000 SWs, 24 kV, 120 SWs/min) has been shown to significantly reduce the size of the hemorrhagic lesion produced in that treated kidney, compared to a protocol without pretreatment. However, since the time available for patient care is limited, we wanted to determine if fewer pretreatment SWs could be used in this protocol. As such, we tested if pretreating with 300 SWs can initiate the same reduction in renal lesion size as has been observed with 500 SWs.
Materials and Methods: Fifteen female farm pigs were placed in an unmodified Dornier HM-3 lithotripter where the left kidney of each animal was targeted for lithotripsy treatment. The kidneys received 300 SWs at 12 kV (120 SWs/min) followed immediately by 2000 SWs at 24 kV (120 SWs/min) focused on the lower pole. These kidneys were compared to kidneys given a clinical dose of SWs with 500 SWs pretreatment, and without pretreatment. Renal function was measured both before and after SW exposure, and lesion size analysis was performed to assess the volume of hemorrhagic tissue injury (% functional renal volume, FRV) created by the 300 SW pretreatment regimen.
Results: GFR fell significantly in the 300 SW pretreatment group by 1 hour after lithotripsy treatment. For most animals, low-energy pretreatment with 300 SWs significantly reduced the size of the hemorrhagic injury (to 0.8±0.4%FRV) compared to the injury produced by a typical clinical dose of SWs.
Conclusions: The results suggest that 300 pretreatment SWs in a voltage ramping treatment regimen can initiate a protective response in the majority of treated kidneys and significantly reduce tissue injury in our model of lithotripsy injury.
J Endourol. 2016 Jun 15. [Epub ahead of print]. FREE ARTICLE
Comments 1
I refer to all previous reviews I have made of the publications of this very active research group. They go on and on with their now 20 years old animal model (Blomgren PM1, Connors BA, Lingeman JE, Willis LR, Evan AP. Quantitation of shock wave lithotripsy-induced lesion in small and large pig kidneys. Anat Rec. 1997 Nov;249(3):341-8.)
In this model they keep using standards in the experiments that they have advised against to use in the clinical situation, like 120 SWs/min. and they use a lithotripter which is outdated in most parts of the world. It is a kind of self-referring experimental system which allows comparing the results of the latest studies with those of the oldest ones. Consequently 11 of the 14 references are self-quotations, like “We have also demonstrated that this injury can be significantly reduced (to ~0.4% FRV) when the SWs are delivered at a slower pulse repetition rate (2,4).” That is:
2. Evan AP1, McAteer JA, Connors BA, Blomgren PM, Lingeman JE.. Renal injury in SWL is significantly reduced by slowing the rate of shock wave delivery. BJU Int 2007; 100:624-628. and
4. Connors BA, Evan AP, Blomgren PM, Handa RK, Willis LR, Gao S, McAteer JA, Lingeman JE. Extracorporeal shock wave lithotripsy at 60 shock waves/min reduces renal injury in a porcine model. BJU Int 2009; 104(7):1004-1008.
These references were used in the 2009 AUA WHITE PAPER “Current Perspective on Adverse Effects in Shock Wave Lithotripsy” of the AUA to advise against 120 SWs/min and recommend 60 shots/min.
The limitations they mention are that their model might not be applicable to other lithotripters and to the clinical situation. The conclusion is weak and the pigs could have served better purposes.