Does extracorporeal shockwave lithotripsy cause hypertension?

Electromagnetic and Electrohydraulic Shock Wave Lithotripsy-Induced Urothelial Damage: Is There a Difference?

PURPOSE

To evaluate and compare the acute effect of electromagnetic and electrohydraulic extracorporeal shockwave lithotripsy (SWL) on the urothelial layers of kidney and ureter.

MATERIALS AND METHODS

Fifty patients, 29 males (58%) and 21 females (42%), with an average age of 51.68 years (range: 37-70) who underwent SWL application in two different centers were included. Twenty-eight patients (56%) were treated with electrohydraulic and 22 (44%) were treated with electromagnetic lithotripsy. Urinary cytologic examinations were done immediately before and after SWL therapy and 10 days later. The average numbers of epithelial cells, red blood cells (RBC), and myocytes were counted under 40 × magnification.

RESULTS

There were significant differences in the number of epithelial cells and RBC before and after immediate application of SWL: 1.66 and 14.9 cells/field, (p = 0.001), 5.44 and 113.45 cells/field, respectively (p = 0.001). The number of RBC was significantly higher in patients treated with electromagnetic lithotripsy than those treated with electrohydraulic: 141.9 and 93.4 cells/field, respectively (p = 0.02). No myocyte or basement membrane elements were detected in any of the cytologic examinations. Cytologic examinations done after 10 days of SWL therapy revealed recovery of all abnormal cytologic findings.

CONCLUSIONS

The acute increments in the number of epithelial cells and RBC after SWL were statistically significant but it was not permanent. SWL-induced urinary urothelial lesion is limited to the mucosal layer and there was no evidence of damage to the basal membrane or muscle layer. Electromagnetic lithotripsy caused high numbers of RBC than the electrohydraulic device on the postimmediate urine cytologic examination.

A systematic review and meta-analysis of new onset hypertension after extracorporeal shock wave lithotripsy

OBJECTIVE

Previous studies on the association between extracorporeal shock wave lithotripsy (SWL) and new onset hypertension have only illustrated contradictory results. In order to illustrate the association between SWL and new onset hypertension, a meta-analysis of case-control and cohort studies was conducted.

METHODS

Relevant literature was searched using PubMed, EMBASE, and the Cochrane Central Search Library. A meta-analysis of the association between SWL and new onset hypertension was performed. Studies were pooled, and summary relative risk was calculated. Subgroup analyses were also conducted.

RESULTS

Eleven studies were eligible for our analysis. No statistical significance was detected between SWL and new onset hypertension (RR = 1.06, 95 % CI 0.83-1.35). No association was observed when stratified analyses were performed on age, gender, study design, bilateral SWL, and different machines.

CONCLUSION

Our analysis indicated that no association was found between SWL and the development of hypertension.

Shock wave lithotripsy associated with greater prevalence of hypertension

OBJECTIVES

To determine whether shock wave lithotripsy (SWL) increases the prevalence of hypertension (HTN) at intermediate follow-up.

METHODS

All patients were treated with the Medstone STS electrohydraulic lithotripter, and the data were recorded prospectively in a centralized database. The data on the development of HTN after SWL was obtained from a questionnaire mailed to the patients who had undergone SWL from November 1999 and January 2002. Controls matched for age, sex, and body mass index were obtained from the National Health and Nutrition Examination Survey, using the demographic, body measurements, medical conditions, and blood pressure data sets. Two sets of matching controls were used to compare the prevalence of HTN between our patients and the NHANES population at SWL and at the follow-up point.

RESULTS

A total of 2041 patients responded to the questionnaire, with a median follow-up of 6 years. No statistically significant difference was found in the HTN prevalence between the patients and matched controls at SWL (26.7% vs 28.0%). At the follow-up point, the prevalence of HTN was greater in our patients (37.8%) than in the controls (32.5%, P=.0009). Of our patients, 15% have developed de novo HTN compared with the predicted rate of 6.25% from the matched controls. Male gender, age, and a greater body mass index were associated with the development of HTN, but none of the SWL parameters (number of shocks, bilateral vs unilateral, and multiple SWL sessions) were significantly associated with HTN.

CONCLUSIONS

The results of our study have indicated a small, but significant, increase in the risk of developing HTN after SWL using a third-generation electrohydraulic lithotripter at intermediate follow-up.

Shock wave lithotripsy is not predictive of hypertension among community stone formers at long-term followup

PURPOSE

Concern exists over the subsequent development of hypertension after shock wave lithotripsy for the treatment of symptomatic urolithiasis. Referral bias and lack of long-term followup have been limitations of prior studies.

MATERIALS AND METHODS

We identified all Olmsted County, Minnesota residents with a diagnosis of urolithiasis from 1985 to 2008. The charts were electronically queried for hypertension and obesity by diagnostic codes, and use of shock wave lithotripsy by surgical codes. All patients first diagnosed with hypertension before or up to 90 days after the first documented kidney stone were considered to have prevalent hypertension and were excluded from analysis. Cox proportional hazards models were used to assess the association of shock wave lithotripsy with a subsequent diagnosis of hypertension.

RESULTS

We identified 6,077 patients with incident urolithiasis with more than 90 days of followup. We excluded 1,295 (21.3%) members of the population for prevalent hypertension leaving 4,782 patients with incident urolithiasis for analysis. During an average followup of 8.7 years new onset hypertension was diagnosed in 983 (20.6%) members of the cohort at a mean of 6.0 years from the index stone date. Only 400 (8.4%) patients in the cohort were treated with shock wave lithotripsy. There was no significant association between shock wave lithotripsy and the development of hypertension in univariate (p = 0.33) and multivariate modeling controlling for age, gender and obesity (HR 1.03; 95% CI 0.84, 1.27; p = 0.77).

CONCLUSIONS

In a large population based cohort of kidney stone formers we failed to identify an association between shock wave lithotripsy and the subsequent long-term risk of hypertension.

Urine cytology to evaluate urinary urothelial damage of shock-wave lithotripsy

Our aim is to study the prospective trial where urine cytology was used to detect the acute urothelial mucosal damage in patients who undergo extracorporeal shock waves lithotripsy (SWL). The study included 48 consecutive patients (28 male, 20 female) with mean age of 49.02 years (range 18-66) who were treated with SWL due to renal stones (30 patients) or upper ureter stones (18 patients). The mean calculi diameter was 12.44 mm (range 5-20). Urinary cytologic examinations were done for all patients immediately before and after SWL therapy and 10 days latter. The average numbers of transitional cells, red blood cells and myocytes were counted under 40 × magnification. In overall patients the average numbers of transitional cells at the cytologic examinations done immediately before and after SWL therapy were 1.6 and 7.53 cell/field, respectively (p = 0.001). The increment in transitional cells at cytologic examination after SWL was significantly influenced only by number of shock waves applied (p = 0.003). No muscle cell was detected in all cytologic examinations. The cytologic examinations which were done after 10 days of SWL therapy showed recovery from all cytologic abnormalities. The acute increment in number of transitional cells after the SWL is not clinically important and it is a temporary change. Urothelial lesion is limited to mucosal layer and there is no evidence of damage to basal membrane or deeper muscle layer. SWL safety on urothelial and muscular layer was demonstrated. However, evaluation of larger series with use of other lithotripters is necessary before reaching any definitive conclusions.

Prospective study of the long-term effects of shock wave lithotripsy on renal function and blood pressure

PURPOSE

We clarified the long-term effects of extracorporeal shock wave lithotripsy on renal function and blood pressure, and its relation to body mass index and type of lithotriptor.

MATERIALS AND METHODS

A total of 100 patients with a single radiopaque renal stone 2 cm or less in length were followed for 18 to 57 months (mean 43.6 +/- 13.8) after being stone-free by extracorporeal shock wave lithotripsy monotherapy using 2 lithotriptors. Mean patient age was 47.9 +/- 9.1 years (range 23 to 66). Nuclear scintigraphy using (99m)technetium-mercaptoacetyltriglycine was done for all patients before extracorporeal shock wave lithotripsy, as well as at the last followup visit to estimate glomerular filtration rate, clearance and split renal function. Blood pressure measurements were recorded at admission and at each followup visit.

RESULTS

Before extracorporeal shock wave lithotripsy treated side mean (99m)technetium-mercaptoacetyltriglycine clearance, glomerular filtration rate and split function were 146.22 +/- 59.48, 52.66 +/- 13.69 and 49.7 +/- 7.31, respectively. At the last followup visit they were 145.1 +/- 58.82 (p = 0.842), 54.85 +/- 15.75 (p = 0.114) and 49.96 +/- 8.68 (p = 0.577), respectively. Of 100 patients 18 were hypertensive before extracorporeal shock wave lithotripsy and 21 were hypertensive at the last followup visit. Mean diastolic blood pressure before extracorporeal shock wave lithotripsy was 80.2 +/- 6.2 vs 80.6 +/- 7.8 mm Hg (p = 0.674) at the end of followup. Mean systolic blood pressure before extracorporeal shock wave lithotripsy was 121.2 +/- 9 vs 121.55 +/- 10.2 mm Hg by the end of the study (p = 0.748). There were no statistically significant differences among body mass index groups or lithotriptor groups.

CONCLUSIONS

Extracorporeal shock wave lithotripsy is a safe procedure and has no significant long-term effects on renal function or blood pressure regardless of the type of machine used or body mass index.

Diabetes mellitus and hypertension associated with shock wave lithotripsy of renal and proximal ureteral stones at 19 years of followup

PURPOSE

SWL has revolutionized the management of nephrolithiasis and it is a preferred treatment for uncomplicated renal and proximal ureteral calculi. Since its introduction in 1982, conflicting reports of early adverse effects have been published. However, to our knowledge the long-term medical effects associated with SWL are unknown. We evaluated these adverse medical effects associated with SWL for renal and proximal ureteral stones.

MATERIALS AND METHODS

Chart review identified 630 patients treated with SWL at our institution in 1985. Questionnaires were sent to 578 patients who were alive in 2004. The response rate was 58.9%. Respondents were matched by age, sex and year of presentation to a cohort of patients with nephrolithiasis who were treated nonsurgically.

RESULTS

At 19 years of followup hypertension was more prevalent in the SWL group (OR 1.47, 95% CI 1.03, 2.10, p = 0.034). The development of hypertension was related to bilateral treatment (p = 0.033). In the SWL group diabetes mellitus developed in 16.8% of patients. Patients treated with SWL were more likely to have diabetes mellitus than controls (OR 3.23, 95% CI 1.73 to 6.02, p <0.001). Multivariate analysis controlling for change in body mass index showed a persistent risk of diabetes mellitus in the SWL group (OR 3.75, 95% CI 1.56 to 9.02, p = 0.003). Diabetes mellitus was related to the number of administered shocks and treatment intensity (p = 0.005 and 0.007).

CONCLUSIONS

At 19 years of followup SWL for renal and proximal ureteral stones was associated with the development of hypertension and diabetes mellitus. The incidence of these conditions was significantly higher than in a cohort of conservatively treated patients with nephrolithiasis.

Extracorporeal Shockwave Lithotripsy for Kidney Stones Reduces Blood Pressure: Use of 24-Hour Ambulatory Monitoring for Study of Blood-Pressure Changes Induced by SWL

PURPOSE

To investigate the effects of shockwave lithotripsy (SWL) on blood pressure with the use of 24-hour ambulatory blood-pressure monitoring (ABPM).

PATIENTS AND METHODS

We studied three groups of patients. Group I consisted of 60 patients with kidney stones treated with SWL. Group II was formed by 30 patients with stones in the lower third of the ureter treated in situ with SWL, and group III consisted of 30 patients with ureteral stones treated with ureteroscopy (URS). The ABPM measurements were performed before stone treatment, immediately after, and then every 3 months through 1 year.

RESULTS

There was no new onset of hypertension in any group. The prevalences of hypertension before stone treatment were 21 (35%), 12 (40%), and 9 (30%) for groups I, II, and III, respectively. One-year post treatment, the numbers of hypertensive patients found for groups I, II, and III were 15 (25%), 11 (33.3%), and 8 (22.2%), respectively. In group I, a statistically significant decrease in blood pressure values was noted 1 year post-treatment (p<0.05). This decrease was related (p<0.05) to the power (r=0.35), as well as to the product of the number and the power (r=0.25), of the shockwaves applied.

CONCLUSION

Extracorporeal lithotripsy for kidney stone may be responsible for a drop in blood pressure possibly caused by alteration in intrarenal metabolism.

Calcium urolithiasis, blood pressure and salt intake

OBJECTIVES

To determine whether stone-formers have higher BP than controls drawn from the general population and matched for age, sex and ethnic origin and to compare the relationship between sodium and calcium excretion in the two groups.

PATIENTS AND METHODS

Thirty-six patients [mean (+/-standard deviation, SD) = 49.0 +/- 11.7 years; range 27-70 years] with kidney or ureteric stones and 108 controls (mean age of 49.6 +/- 6.8 years; range 39-61 years), matched for gender, ethnic origin and age group were studied. Patients and controls underwent physical measurements, a venous blood sample and they were asked to collect a 24-h urine sample for sodium, potassium, calcium and creatinine.

RESULTS

Stone-formers were significantly heavier and had higher BP than age-, sex- and ethnic-matched population controls. Whilst the difference in systolic BP was independent of the difference in body mass index [16.8 mmHg (7.2-26.4 mmHg), p = 0.001), the difference in diastolic BP was attenuated after adjustment for body mass [1.8 (-3.4 to 7.1), p = 0.49]. Stone-formers passed less urine than controls [-438 ml/day (95% CI -852 to -25), p = 0.038]. They had higher urinary calcium than controls [+3.7 mmol/day (2.8-4.6 mmol/day), p < 0.001], even when expressed as ratio to creatinine [+0.20 (0.11-0.29), p < 0.001]. Sodium excretion was positively associated with urinary calcium in both stone-formers and in controls. The slopes were comparable (0.92 vs 0.98 mmol Ca/100 mmol Na) so that for any level of sodium excretion (or salt intake), stone-formers had a higher calcium excretion than controls.

CONCLUSIONS

In stone-formers, the BP is higher than in controls. Stone-formers excrete more calcium than controls do. In stone-formers and controls, the relationship between urinary sodium and calcium is similar. Since this relationship results from an effect of sodium on calcium, a reduction in salt intake may be a useful method of reducing urinary calcium excretion in stone-formers. However, the "relative" hypercalciuria seen in stone-formers is independent of salt intake and may well reflect an underlying genetic predisposition.

Early observations of the effect of extracorporeal shockwave lithotripsy on blood pressure: a prospective randomized control clinical trial

OBJECTIVE

To determine, in a randomized controlled clinical trial, the effect of extracorporeal shock wave lithotripsy (ESWL) on blood pressure.

PATIENTS AND METHODS

The trial included 228 patients with small (< 15 mm) asymptomatic calyceal stones who were randomised to undergo ESWL (113 patients) or to an untreated (observed) control group (115 patients). Blood pressure was recorded at randomization using a standardized protocol. Patients undergoing ESWL received a mean (SD) of 5281 (3462) shocks over a mean of 1.75 sessions on one of two lithotripters. Patients were then followed annually, assessing blood pressure and changes in medication. Data were analysed on an intention-to-treat basis.

RESULTS

At randomization, 43% of patients in the control group and 53% in the ESWL group were hypertensive. Of the 228 randomized, 200 patients completed at least one annual follow-up, of whom 192 (93 in the control and 99 in the ESWL group) had their blood pressure recorded. The mean follow-up was 2.2 years; 35 (37%) patients in the control and 46 (46%) in the ESWL group were hypertensive (P = 0.19). Seven (7%) patients in the control group and 11 (11%) in the ESWL group were newly diagnosed to be hypertensive (P = 0.35).

CONCLUSIONS

In this randomized controlled clinical trial there was no evidence that ESWL causes changes in blood pressure.

Changes in resistive index following extracorporeal shock wave lithotripsy

BACKGROUND

Extracorporeal shock wave lithotripsy (ESWL) has replaced most surgical and endourologic forms of therapy for upper urinary tract stone disease. Despite its proved safety and efficacy, its adverse effects on renal function are still to be identified. A newer diagnostic technique, color Doppler ultrasonography, has brought a new insight into renal function. It enables precise evaluation of the renal vascular supply. Changes in intrarenal vascular resistance after ESWL were studied with Doppler ultrasound techniques.

METHODS

In 70 consecutive patients the resistive index (RI) was measured at an interlober artery before and 30 min after ESWL in the treated and contralateral kidneys. In 17 patients, a follow-up Doppler study was performed 1 week after ESWL.

RESULTS

In the treated kidneys, the RI significantly increased from 0.656+/-0.053 (mean +/- SD) at baseline to 0.682+/-0.053 (P<0.0001). There was no significant correlation of increase in RI with patient age (r = 0.010) or with pre-ESWL blood pressure (r = 0.002). Elderly patients (> or =60 years old, n = 31) had higher RI levels on baseline than younger patients (<60 years old, n = 39). In 18 of the 31 (58.1%) elderly cases the RI were elevated to greater than 0.7, indicating pathologic changes. In younger patients, only 9 (23.1%) experienced increase in RI up to 0.7 or greater. The contralateral untreated kidneys showed significant change in RI before (0.664+/-0.045) and after (0.679+/-0.049) lithotripsy in elderly patients (P<0.005). A follow-up Doppler study showed that the mean RI returned to pretreatment levels after 1 week.

CONCLUSIONS

Because of higher RI levels on baseline, elderly patients have a higher risk of post-ESWL renal tissue damage than younger patients. Clinical implication of RI change in the contralateral kidneys in this study remains to be answered. The measurement of changes in RI with Doppler ultrasound techniques after ESWL may provide useful information for clinical diagnosis of renal tissue damage.

New onset hypertension after extracorporeal shock wave lithotripsy: age related incidence and prediction by intrarenal resistive index

PURPOSE

In a recent study we found an increased resistive index immediately after extracorporeal shock wave lithotripsy (ESWL) in patients older than 60 years, which suggests renovascular disturbance. The present 26-month followup study was undertaken to investigate the relevance of elevated resistive index levels and the incidence of new onset hypertension.

MATERIALS AND METHODS

Of the initial 76 patients 57, including 20 of the 23 at risk patients 60 or greater years, group 3), were followed for more than 26 +/- 6 months after ESWL. Followup included 2 resistive index measurements by Doppler ultrasound of the treated and the contralateral kidney, at least 2 blood pressure measurements 1 week apart and excretory urography as well as determination of plasma renin activity in 9 patients.

RESULTS

With 1 exception, elevated resistive index levels and hypertension were observed exclusively in patients older than 60 years. In these patients the resistive index ranged between 0.65 and 0.86 (mean plus or minus standard deviation 0.74 +/- 0.05, normal less than 0.7). This increase in resistive index was statistically significant (p < 0.0001). Compared to the levels obtained immediately after ESWL, the resistive index continued to increase in all 9 patients older than 60 years who had hypertension (45%), whereas in the normotensive patients the resistive index was either stable or decreased. There was a strong positive correlation (0.903) between pathological resistive index levels and blood pressure.

CONCLUSIONS

Patients older than 60 years are at risk for disturbances of renal perfusion as assessed by the resistive index, and 45% of these patients have new onset hypertension within 26 months of treatment.

Effects of extracorporeal shockwave lithotripsy on urinary concentration of epidermal growth factor

In a prospective study, we tried to determine whether extracorporeal shockwave lithotripsy (SWL) has any effect on urinary epidermal growth factor (EGF) concentrations and to investigate whether EGF can be used as a marker for detecting shockwave-induced impairment of distal tubular cells. A total of 12 patients with renal pelvic or caliceal stones < or = 2 cm undergoing anesthesia-free SWL without ancillary measures and a control group of 10 patients without any urologic symptoms were included in this study. The urinary concentrations of EGF were measured by radioimmunoassay before and 4 hours, 24 hours, and 7 days after SWL. Relative urinary EGF concentrations were expressed as the ratio of EGF to creatinine (ng/mL creatinine). The mean urinary EGF concentration (mean +/- standard error) in control subjects and patients with renal pelvic or caliceal stones before SWL was 23.90 +/- 3.15 ng/mL creatinine and 22.18 +/- 6.85 ng/mL creatinine, respectively (p > 0.05). In patients with stones, we found a decrease in urinary EGF concentration 4 hours, 24 hours, and 7 days after SWL. Indeed, 7 days after SWL, the EGF concentration was on average half of the original value, a biologically significant, although not statistically significant, decrease.

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.

Blood pressure changes after extracorporeal shock wave lithotripsy in normotensive patients

To evaluate the blood pressure changes caused by extracorporeal shock wave lithotripsy 102 patients 5 to 81 years old (mean age 40 years) with normal blood pressure and kidney lithiasis were monitored during a mean period of 22 months. There were 61 male (group 1) and 41 female (group 2) patients. Patients were evaluated by measurement of the diastolic pressure and the average arterial pressure before and after lithotripsy. Hypertension was considered when the diastolic pressure was greater than 90 mm. Hg for 2 weeks. The amount of shock waves applied in each case ranged from 1,250 to 6,000, with a mean of 4,000 shock waves at a median intensity of 18.1 kv. The incidence of hypertension after extracorporeal shock wave lithotripsy was 3.92%, which is similar to that of a normal population, although the diastolic pressure was statistically higher after treatment in both groups. In the male patients the diastolic pressure increased from 79.26 (+/- 9.7) to 81.47 (+/- 10.1) mm. Hg and in female patients it ranged from 76.58 (+/- 8.3) to 79.26 (+/- 9.9) mm. Hg. Similarly, the average arterial pressure was equally higher in the female group, ranging from 89.88 to 91.75 mm. Hg. In the male group the difference was not statistically significant, despite an increase from 94.5 to 95.8 mm. Hg.

Arrhythmia during extracorporeal shock wave lithotripsy

A prospective study of arrhythmia during extracorporeal shock wave lithotripsy (ESWL) was performed in 50 patients, using an EDAP LT01 piezoelectric lithotriptor. The 12-lead standard ECG was recorded continuously for 10 min before and during treatment. One or more atrial and/or ventricular ectopic beats occurred during ESWL in 15 cases (30%). The occurrence of arrhythmia was similar during right-sided and left-sided treatment. One patient developed multifocal ventricular premature beats and ventricular bigeminy; another had cardiac arrest for 13.5 s. It was found that various irregularities of the heart rhythm can be caused even by treatment with a lithotriptor using piezoelectric energy to create the shock wave. No evidence was found, however, that the shock wave itself rather than vagal activation and the action of sedo-analgesia was the cause of the arrhythmia. For patients with severe underlying heart disease and a history of complex arrhythmia, we suggest that the ECG be monitored during treatment. In other cases, we have found continuous monitoring of oxygen saturation and pulse rate with a pulse oximeter to be perfectly reliable for raising the alarm when depression of respiration and vaso-vagal reactions occur.

ESWL and arterial hypertension

Two groups of patients with normal arterial pressure were studied; a retrospective group of 50, treated with Dornier HM3 at Salzburg Hospital and a prospective group of 23 treated with Lithostar Plus at Bolzano Hospital. It was concluded that therapy with ESWL did not bring about an increase in arterial pressure.

Blood pressure changes following extracorporeal shock wave lithotripsy for urolithiasis

Hypertension after extracorporeal shock wave lithotripsy (ESWL) has been a controversial subject. Changes in blood pressure were studied in 262 patients (mean age 47.8 years) 18.6 months after ESWL. According to World Health Organization criteria the number of patients who showed a decrease exceeded those who showed an increase in blood pressure. The patients who have been on antihypertensive therapy showed a significantly greater decrease in blood pressure than those without medication. Of 192 normotensive patients diastolic pressure increased 1.2 mm. Hg and 2 (1.0%) had hypertension 18.4 months after ESWL. Annualized increase in diastolic pressure and new onset of hypertension were calculated to be 0.78 mm. Hg and 0.65%, respectively. Significant elevation of diastolic pressure was noted in the patients who received a larger number of shock waves. Blood pressure should be carefully followed after ESWL especially in patients who have been treated by a greater number of shock waves.

Treatment of ureteral calculi with extracorporeal shock wave lithotripsy using the Lithostar device

Shock wave requirements for fragmentation and the ultimate outcome after extracorporeal shock wave lithotripsy (ESWL) with the Lithostar device were analyzed in 107 renal units with solitary ureteral calculi. In situ treatment was done in 54 stones without prior manipulation and in 15 after failure of endoscopic manipulation. A total of 25 ureteral calculi was treated after bypass with a ureteral catheter or stent and 13 after push back to the pelvicaliceal system. Shock wave requirement for fragmentation was significantly higher for calculi of 101 to 400 mm. X mm. when compared with the requirement for smaller calculi. Shock wave requirement was also significantly higher for patients with similar sized stones treated in the prone compared to the supine position. The average number of shock waves required for disintegration was not significantly different among in situ or any of the manipulation categories of similar sized stone populations. Over-all satisfactory clearance was achieved in 77.5% of the treated ureteral calculi. Clearance status was unaffected by size up to 400 mm. X mm. and the position of the patient during treatment (prone or supine). Clearance of ureteral stones treated in situ without prior manipulation (76.5%) was numerically inferior, although statistically insignificant, to that for successfully manipulated calculi (bypassed 88% and pushed back 92.3%) but it was significantly better than the outcome obtained after failed manipulation (46.2%). ESWL with the Lithostar device is a successful mode of treatment within the entire ureteral length, and a vigorous attempt at push back before lithotripsy is unnecessary.

Cystine stones: the impact of new treatment

The hardness and frequent recurrence of cystine stones present a special challenge to the urologist. In this study, 15 cystinuric patients (11 males, 4 females; mean age 36 years, range 17-54) were treated and followed up over a period of 30 months (range 2-40). Most patients had previous history of open surgery. The diagnosis of cystinuria was confirmed by metabolic studies and infrared spectrometry of stones. Over the follow-up period recurrence was observed in 23 instances in 11 patients, leading to 38 "stone treatments" on 74 cystine stones. The percutaneous approach was used alone in 9 cases and in association with extracorporeal shock wave lithotripsy (ESWL) in 9 cases. ESWL was used alone in 18 cases. Medical treatment included high fluid intake, alkalinisation and Thiola (tiopronin, N-(2-mercaptopropionyl)glycine) in 6 patients. The overall stone-free rate assessed 3 months after treatment was 44.7%, which compares poorly with the rate for non-cystine stones. The recurrence rate is very high and instrumental treatment should not therefore be used excessively; it is indicated only for stones that are symptomatic or refractory to intensive medical therapy.

The effects of extracorporeal shock wave lithotripsy on renal growth, function and arterial blood pressure in an animal model

The long-term effects of extracorporeal shock wave lithotripsy (ESWL*) on children treated for renal calculi are unclear. To study the long-term bio-effects of this mode of treatment on the immature animal we evaluated 30 New Zealand white rabbits at 7 weeks of age for weight, serum blood urea nitrogen and creatinine, and arterial blood pressure after which they underwent left nephrectomy. Each group of 5 rabbits received ESWL of varying levels (500 to 3,000 shock waves) to the remaining right kidney using the Northgate SD3 lithotriptor (spark gap mediated). One control group received no shock waves. At maturity (16 weeks) the aforementioned parameters were measured again, and the kidneys and any grossly abnormal adjacent organs were examined. We found no significant change in total animal growth, renal growth, renal function or perirenal organs in the post-ESWL groups versus the control group. All post-ESWL groups had an increase in mean arterial blood pressure versus the control group with 3 of 6 groups showing significant increases (p less than 0.05). Histological renal changes, seen at all energy levels of ESWL delivered, included interstitial fibrosis, tubular atrophy, glomeruli destruction, capsular thickening, perivascular fibrosis and mild arteriole wall thickening. Changes were proportional to the number of shocks received. We conclude that ESWL delivered to immature animals does not significantly affect renal growth and function but it can cause significant permanent histological renal changes even at low doses and may result in an increase in adult mean arterial blood pressure.