1460 PREDICITION OF RENAL STONE FRAGILITY IN RESPONSE TO SHOCK WAVE LITHOTRIPSY BY THEIR RADIOLOGIC APPEARANCE

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THE JOURNAL OF UROLOGY姞

renal radioisotope scans were performed for 71 patients. At the last follow-up, deferential GFR was stable in 53 patients (74.5%) and improved in 12 (17%). In the remaining 6 patients (8.5%), the preoperative differential GFR of 68, 67, 37, 30, 25 and 22 had decreased to 54, 58, 27, 20, 16, and 7 respectively. However, only one of them showed no contrast excretion by the kidney on IVU. CONCLUSIONS: The long-term functional results of PNL for staghorn stones are satisfactory as 91.5% of kidneys showed stable or improved GFR. Long-term follow-up is mandatory especially for patients with residual stones because of the high rate of growth of them. Source of Funding: None

1459 SHOCKWAVE LITHOTRIPSY IS ASSOCIATED WITH A HIGHER PREVALENCE OF HYPERTENSION Philip Barbosa*, Antoine Makhlouf, Daniel Thorner, Roland Ugarte, Manoj Monga, Minneapolis, MN INTRODUCTION AND OBJECTIVES: The presence of an association between hypertension (HTN) and shockwave lithotripsy (SWL) is controversial. Our objective was to determine if the prevalence of hypertension is increased at intermediate follow-up in patients previously treated with SWL when compared with controls matched for age, sex, and BMI from the National Health and Nutrition Examination Survey (NHANES) database. METHODS: Data regarding patient demographics, BMI, stone location, number and size, treatment parameters (number of shocks, rate, energy), and treatment outcomes (complications, retreatment rates, stone-free rates) were recorded prospectively in a centralized database maintained by Midwest Stone Management. All patients were treated with the Medstone STS electrohydraulic lithotripter. Data on the development of HTN after SWL was obtained via questionnaire survey. Controls were obtained from the NHANES database. NHANES tables used in this study were the demographic (DEMO_D), body measurements (BMX_D), medical condition (MCQ_D) and blood pressure (BPQ_D) datasets. These were imported into the R statistical package. NHANES subjects were matched to patients using age and BMI at time of SWL and at time of follow-up survey. RESULTS: 2041 patients responded to the questionnaire. The median follow-up was six years. There was no statistical difference in HTN prevalence between patients and matched controls at the time of SWL (26.7% vs. 28.0). However, at follow-up, patients had statistically significantly higher rates of hypertension compared to controls (37.8% compared to 32.5%. p⫽0.0009). Thus, among patients who did not report a diagnosis of HTN at the time of SWL (73.3% of total), 15% reported having HTN at time of survey. The expected number, using the matched controls would have been 6.25 %. To determine which patient and SWL variables were associated with development of HTN, a multivariate analysis was conducted, where patients without a diagnosis of HTN at time of survey were compared to those with reported HTN onset between SWL and follow-up. None of the SWL parameters (number of shocks, bilateral versus unilateral or multiple SWL) were statistically associated with HTN. However, male gender, age, and higher BMI were all associated with development of HTN. In addition, those patients with an abnormal reading of BP on the day of SWL – but without a diagnosis of HTN- were more likely to develop HTN later on. CONCLUSIONS: Our study indicates a small but significant increase in the risk of developing HTN after receiving SWL with a third-generation electrohydraulic lithotripter at intermediate follow up of 6 years. Source of Funding: None

Vol. 183, No. 4, Supplement, Tuesday, June 1, 2010

1460 PREDICITION OF RENAL STONE FRAGILITY IN RESPONSE TO SHOCK WAVE LITHOTRIPSY BY THEIR RADIOLOGIC APPEARANCE Mohamed Nady, Assiut, Egypt; Alaa AbdelHafez, Sohag, Egypt; Mohamed ElKoushy, Ismailia, Egypt; Emadeldeen Ali Salah*, Assiut, Egypt INTRODUCTION AND OBJECTIVES: Extracorporeal shock wave lithotripsy (ESWL) provides a non invasive method for treatment of renal and ureteral calculi. Currently, fluoroscopic stone targeting remains a major component of ESWL. A plain (KUB) film is often required to plan lithotripsy treatment. The appearance of a stone on KUB (size, shape and radiodensity) might give a clue for the success of ESWL. The aim of this work was to evaluate the efficacy of ESWL in treatment of different types of upper urinary tract stones regarding their radiological characteristics like texture homogeneity, surface smoothness and radiodensity degree in relation to last rib. METHODS: About 336 patients with single renal pelvic stone less than 2cm were treated by ESWL at 3 centers. The patients were classified based on stone imaging characters. Type I classification was done according to how homogeneous were the stones while type II classification was based on the surface outline of the calculi. Finally, type III classification according to radiodensity degree of stones in relation to last rib as landmark comprised three subclasses with less, equal and more density than last rib. The percentage of stone free rate (SFR) within 3 months post ESWL was calculated. The results were classified based on imaging studies. RESULTS: Homogenous stones were 53% clear after ESWL, while the majority (86%) of nonhomogenous stone patients became stone free (p⬎ 0.01). On the other hand, smooth and rough calculi showed 61% and 77% SFR (p⬎ 0.05). Lastly, the SFRs of less, same and more dense stone than the last rib were 82%, 69% and 56% respectively. CONCLUSIONS: The efficacy of ESWL in treatment of different types of upper urinary stones is related to the radiological characteristics of the stone. Stones which are heterogonous, rough or less dense in KUB film are more likely to disintegrate by ESWL

Source of Funding: Routine Department Work