0022-534 7/92/14 73-0553$03.00/0 Vol. 14-1, 553-558, March 1992
THE JOURNAL OF UROLOGY Copyright© 1992 by AMERICAN UROLOGICAL ASSOCIATION, INC.
Printed in U.S.A.
BLOOD PRESSURE CHANGES FOLLOWING EXTRACORPOREAL SHOCK WA VE LITHOTRIPSY FOR UROLITHIASIS MASAO YOKOYAMA, FUMIO SHOJI, RYOZO YANAGIZAWA, MIKIO KANEMURA, KEN KITAHARA, SATORU TAKAHASI, KOJI KAWAI, HIROYUKI ODA, MORIAKI OSAKA AND HIROMI RANDA From the Department of Urology, Toranomon Hospital, Tokyo, Japan
Hypertension after extracorporeal shock wave lithotripsy (ESWL *) has been a controversial subject. Changes in blood pressure were studied in 262 patients (mean age 4 7.8 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. KEY WORDS:
blood pressure, extracorporeal shockwave lithotripsy, urinary calculi
Extracorporeal shock wave lithotripsy (ESWL) induced drastic changes in the treatment of stones in the upper urinary tract. Its safety, efficacy and effectiveness were established in a large number of patients and its indication has been broadened. Currently, almost all stones in the upper urinary tract can be treated by ESWL alone or with the advent of endourological procedures. However, little has been known about the late complications of this new treatment modality. Hypertension following ESWL has been a controversial subject since 1987. Lingeman and Kulb, 1 as well as Newman et al2 reported that new occurrence of hypertension was observed in approximately 8% of the patients 1 year or longer after ESWL. The former group noted that an additional 15.2% of 295 patients showed elevation of diastolic blood pressure, although not requiring treatment. The annualized value of diastolic blood pressure elevation was 1.4 to 2.4 mm. Hg in 506 patients. 3 Williams et al, the latter group, studied 21 patients by quantitative radionuclide renography and found that effective renal plasma flow was decreased in the treated kidney 17 to 21 months after ESWL and 2 patients had hypertension. 4 They expanded the blood pressure surveillance and found that 7 of 91 patients (8%) became hypertensive. These studies claimed that hypertension is a possible late sequela of ESWL. Several groups performed blood pressure surveys after ESWL but they could not verify an increase in hypertension. 5 - 8 The problem is complicated by small but consistent elevation of blood pressure by aging. Clinically, ESWL causes gross hematuria. 9 Edema, congestion, interstitial hemorrhage and occasionally large renal hematomas are discernible by ultrasound and computerized tomography 10 as well as magnetic resonance imaging. 11 Serum and urinary enzymes increase after ESWL. 12 Most of such changes disappear within 3 weeks but some may persist for longer periods 13 and may cause hypertension. In view of the importance of risk of hypertension we performed retrospective analysis of blood pressure changes after ESWL in 262 patients.
stones. The patients were followed for an average of 18.6 months at the outpatient clinic of our hospital between 1986 and 1989. ESWL was performed with a Dornier HM3 lithotriptor, original type, with the patient under epidural anesthesia. The upper limit of shock waves was 3,000 in 1 treatment session. The average patient received a total of 2,076 shocks in 1.2 sessions (table 1). Blood pressure was measured on the right arm with the patient in the sitting position after 5 minutes of rest. Blood pressure levels before ESWL were obtained from the medical records, in which at least 4 separate blood pressure measurements were recorded. Pre-ESWL blood pressure value was assigned as an average of 2 selected measurements that represented a stable condition of the individual patient. Hypertension (blood pressure 160/95 or greater) and normotension (blood pressure less than 140/90) were defined according to the World Health Organization criteria. 14 Any value in between was classified as borderline hypertension. Overall, systolic, diastolic and mean blood pressures were compared. Mean blood pressure was defined as elevated or lowered when changes were larger than 6 mm. Hg. Student's paired t test was used whenever possible to compare the paired values. A nonpaired t test was used for the analysis in the rest of the study.
PATIENTS AND METHODS
A total of 262 patients (187 men and 75 women) with a mean age of 47.8 years underwent ESWL for renal and ureteral Accepted for publication March 15, 1991. Supported in part by Grant No. 62570738 from Japanese Ministry of Education and Okinaka Memorial Institute for Adult Diseases. * Dornier Medical Systems, Inc., Marietta, Georgia. 553
Distribution of blood pressure before and after ESWL. Of 262 patients with a mean age of 47.8 ± 12.8 years (standard deviation) blood pressure before ESWL was hypertensive (160/95 or greater) in 15, borderline hypertensive in 46 and normotensive (less than 140/90) in 201, respectively (table 2). A total of 231 patients was free of antihypertensive drugs, while 31 received antihypertensive treatment before and after ESWL. Of the patients 192 (73.3%) were normotensive without medication (table 1). Thus, the incidence of hypertension was calculated as 26.7% before ESWL. The blood pressure after an average of 18.6 ± 8.1 months was hypertensive in 7 patients, borderline hypertensive in 44 and normotensive in 211, respectively (table 2). When each parameter in an individual patient crossed the range of the definition of normotensive, borderline hypertensive and hypertensive it was defined as elevated or lowered. Of 262 patients 6.5% showed elevation and 11.8% had a decrease in the blood pressure as a whole. The numbers of patients with decreased blood pressure exceeded those with elevated blood
YOKOYAMA AND ASSOCIATES
pressure in all parameters, that is systolic, diastolic and mean blood pressures (table 3). Blood pressure and its changes after ESWL. The mean values of each parameter before ESWL and at followup are shown in table 4. Systolic blood pressure was decreased from 129.1 to 126.4 mm. Hg and the difference (-2.7 ± 12.7) was statistically significant (p