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Urethral Stricture After Cardiovascular Surgery, A Retrospective and a Prospective Study
·~
0022-534 7/83/1306-1100$02.00/0 Vol. 130, December
THE JOURNAL OF UROLOGY
Copyright © 1983 by The Williams & Wilkins Co.
Printed in U.S.A.
URETHRAL STRICTURE AFTER CARDIOVASCULAR SURGERY, A RETROSPECTIVE AND A PROSPECTIVE STUDY A. ABDEL-HAKIM,* J. BERNSTEIN,t J. TEIJEIRA AND M. M. ELHILALI:j: From the Departments of Uro/,ogy and Cardiovascular Surgery, Centre Hospitalier Uniuersitaire, Sherbrooke, Quebec, Canada
ABSTRACT
In a review of our cases presenting with urethral stricture we noted a high incidence following cardiovascular surgery. A retrospective study was done, including 87 patients treated for urethral stricture and 304 undergoing open heart surgery during the same period, to search for a possible etiologic factor. A prospective study also was done on 98 patients subjected to cardiovascular surgery. Strictures developed in 17.5 per cent of 63 patients who had a urethral catheter placed for urinary diversion at operation compared to none of 35 who had a suprapubic cystocatheter. We believe that the urethral catheter is at least partly responsible for stricture formation. Associated factors, for example urethral ischemia, may be contributory. Stricture of the male urethra remains one of the difficult challenges facing the urologist. Iatrogenic traumatic strictures usually are the most common type. 1• 2 In a review of the cases of urethral stricture treated at our hospital during 2 years we found the incidence to be high following cardiovascular surgery, which was the second most common etiologic factor. A retrospective study was done to search for an acceptable etiology and a prospective study was done to verify our hypothesis. PATIENTS AND METHODS
Retrospective study. We diagnosed 87 patients with urethral stricture between July 1979 and July 1981. The 87 patients were distributed into 4 major groups: 1) after urologic surgery (34), 2) cardiovascular surgery (32), 3) medical departments (12) and 4) other surgical departments (9) (table 1). Mean patient age was 60 years. The youngest patients were those who underwent cardiovascular surgery (mean age 56 years). Of the patients 34 underwent urologic surgery, including 26 who had endoscopic procedures, mostly transurethral resection of the prostate (table 2). There was a history of recent cardiovascular surgery in 32 patients: open heart surgery with extracorporeal circulation in 21 (24.1 per cent) and peripheral vascular surgery in 11 (12.7 per cent). Patients undergoing cardiovascular surgery had 18F catheters, whereas those undergoing transurethral prostatic resection had 24F catheters. All catheters were made of latex and were purchased from the same manufacturer. Patients with possible urethral strictures were evaluated by uroflowmetry and retrograde urethrography. We analyzed 5 perioperative parameters in 304 patients operated upon for cardiovascular diseases between July 1979 and July 1981, namely pump time, heparin dose, protamine dose, degree of hypothermia and platelet count at the end of extracorporeal circulation. Prospective study. To verify the role of the urethral catheter in causing the strictures, a prospective double-blind paired study was done between August 1981 and August 1982. The patients were paired according to risk factors, including age, urinary symptoms, urinary tract infection, previous urethral manipulations, urethral trauma, physical examination, uroflowmetry and so forth. Each patient was assigned randomly to either urethral catheterization (68 patients) or a suprapubic Accepted for publication March 4, 1983.
* Current address: Urology Department, Cairo University, Cairo, Egypt.
t Current address: Urology Department, Toulouse University, Toulouse, France. :j:Requests for reprints: Department of Urology, Centre Hospitalier Universitaire, Sherbrooke, Quebec, Canada JlH 5N4.
cystocatheter (42 patients). The 18F latex Foley urethral catheters were inserted by the cardiac surgeon or a urologist in the operating room with the patient under general anesthesia. Cystocatheters were placed by a urologist the night before the operation with the patient under local anesthesia. The difference between the number of patients in each group is owing to the fact that not all patients could be paired. Patients were followed immediately postoperatively before leaving the hospital, at 6 weeks, and 3 and 9 months postoperatively by urologic history, examination, urinalysis, urine culture and uroflowmetry. The investigations of urethral strictures included retrograde urethrography and urethrocystoscopy. The statistical differences were compared using Student's t test. RESULTS
Retrospective study. Traumatic catheterization as an etiological factor for urethral stricture was excluded in this study by the fact that a urologist either supervised or practiced the catheterization in the operating room. Urinary infection was found in 6 patients (6.9 per cent): 3 after a cardiac operation, 2 after urologic manipulations and 1 after a vascular operation. The causative organisms were Escherichia coli in 3 patients, Pseudomonas in 2 and enterococci in 1. The average duration of catheterization was 1½ days after cardiovascular surgery compared to 1 day after transurethral resection. Urethral strictures were manifest an average of 16 days after cardiovascular surgery compared to an average of 23 days after transurethral resection. The difference was not significant. In 17 of 21 patients after cardiovascular surgery symptoms of urethral strictures occurred during the first 3 months postoperatively. Uroflowmetry was obstructive consistently, with a mean maximum flow of 9 ml. per second and a mean voiding time of 37 seconds, for a volume of 210 ml. The site of stricture similarly was distributed between the distal urethra in 47 patients and bulbar urethra in 49 (9 patients had multiple strictures). Five parameters in 304 patients who underwent open heart surgery during the same interval (July 1979 to July 1981) were compared and 21 patients suffered urethral strictures (table 3). No significant differences were found between the 2 groups for the parameters compared. Prospective study. Of the 110 patients studied we obtained adequate data on 98. Three patients died, 2 in the catheter group were lost to followup and 2 were excluded owing to difficult catheterization preoperatively. Also excluded were 5 patients from the cystocatheter group: 2 owing to severe hematuria postoperatively necessitating urethral catheterization and 3 because of postoperative urinary retention treated by urethral catheterization.
llOO
URETHRAL STRICTURE AFTER CARDIOVASCULAR SURGERY TABLE 1.
Patients with urethral strictures Mean Age (yrs.}
Urologic Cardiovascular Medicine Surgery Totals
TABLE 2.
No. Pts. (%}
63 56 58 64
34 32 12 9
60
8'i
(39.1) (36.8) (13.8) (10.3) (100)
Distribution of patients with urethral strictures after urologic procedures No.(%}
Endoscopic surgery: Transurethral resection of prostate Transurethral resection of vesical tumor Urethrolithotomy External sphincterotomy Cystoscopy Subtotal Retropublic prostatectomy Surgery for urethral trauma Partial cystectomy (vesical tumor} Radical nephrectomy Total
TABLE 3.
21 2 1 1 1
(24.1) (2.3) (1.1) (1.1) (1.1)
26 (29.9) 3 3 1 1
(3.4) (3.4) (1.1) (1.1)
34
Possible risk factors related to cardiovascular surgery With Strictures
No. pts.* Pump time (mins.} Heparin dose (mg.) Protamine dose (mg.} Hypothermia (C} Platelet count
21 98 320 409 29 118,315
Without Strictures 283 97 299 410
27 121,600
* Nonsignificant differences.
Of 63 patients with urethral catheters postoperatively 11 (17.5 per cent) suffered strictures compared to none of the cystocatheter group. Five patients with strictures were paired (45.5 per cent). One patient had postoperative urinary infection caused by E. coli, which was treated before discharge from the hospital. In 81.8 per cent of the patients symptoms of urethral stricture appeared in ~3 months. The site of stricture was meatal in 4 patients, penile in 4, bulbar in 6 and membranous in 2. Four patients had multiple strictures. DISCUSSION
Urethral reaction to foreign objects depends on many variables, such as catheter material, catheter size, concurrent trauma and/or infection, length of exposure and individual patient or animal variations. 8• 4 In animal experiments cellular reaction causing thrombosis in the submucosal area, and subsequent ischemic necrosis and scarring of the urethra were shown. 3 Urethral reaction to long-standing catheters was compared to bedsores. 1 In our series of urethral strictures following cardiovascular surgery traumatic catheterization as an etiological factor was excluded. A urologist either observed or practiced the catheterization immediately preoperatively in the operating room with the patient under general anesthesia. Urinary infection as a contributing factor does not seem to have a role in our series, since only 1 of those patients who suffered stricture had postoperative urinary infection that was cured before the patient was discharged from the hospital. The average duration of postoperative catheterization was 1.5 days and, therefore, prolonged catheterization as a contributing factor can be excluded. A contributing factor related to the cardiac surgery procedure itself was studied. We compared 5 parameters related to the cardiac surgery in 2 populations: 283 patients who did not have stricture and 21 undergoing the same procedure who did. No significant difference was found in the parameters studied.
1101
Since we were unable to find a classical urological factor or a cardiac factor, it was presumed that an abnormal urethral reaction to the catheter can explain the high incidence of urethral stricture in these patients. Two hypotheses were made: 1) a hypersensitivity of the urethra to the presence of the catheter (a tissue reaction can occur followed by fibrosis and stricture formation) and 2) an associated urethral ischemia to explain the fact that only some patients are at risk. These patients undergoing cardiovascular surgery frequently are suffering from marked peripheral vascular pathological conditions. The presence of a relative ischemia of the urethral wall in association with a foreign body and an exaggerated urethral response would explain the higher incidence of strictures in these patients. To verify the first hypothesis we performed a prospective double-blind paired study since August 1981. The patients were paired according to risk factors and each was assigned randomly to a urethral catheter or a cystocatheter. None of the patients with a cystocatheter suffered a stricture compared to an incidence of 17.5 per cent in the other group. We found similar observations in a review of the literature. In January 1982 Ruutu and associates noted an epidemic of urethral strictures following open heart surgery that led them to abandon urethral catheterization and to place cystocatheters routinely. 5 Soon after, similar experiences were reported. Walsh,6 and Smith and Neligan 7 explained the incidence as related to the type of urethral lubricant used. Fraser and associates explained the pathological condition as related to the size of the catheter and to chemical irritation caused by starch powder from surgeon gloves contaminating the catheters. 8 Wesley-James noted a 50 per cent incidence of urethral stricture after open heart surgery and explained it as secondary to the use of a cheaper type of latex catheter. 9 However, in our series the same type of catheters, lubricant and surgical gloves is used for all patients undergoing urethral catheterization for any cause. The incidence of urethral strictures after cardiovascular surgery is much higher than the incidence in patients even undergoing transurethral resection, in whom more urethral trauma is inevitable. A larger caliber catheter is applied using the same lubricant and same catheter material for almost the same duration. Routine cystocatheter urinary diversion before open heart surgery is not without risk in an anticoagulated patient. We believe that the urethral catheter is at least partly responsible for the high incidence of urethral stricture following cardiovascular surgery. Our study is being extended to verify the second hypothesis of possible urethral ischemia, in an attempt to identify the patient at risk. REFERENCES
1. Blandy, J.P.: Urethral stricture. Postgrad. Med. J., 56: 383, 1980. 2. Walther, P. C., Parsons, C. L. and Schmidt, J. D.: Direct vision internal urethrotomy in the management of urethral strictures. J. Urol., 123: 497, 1980. 3. Painter, M. P., Borski, A. A., Trevino, G. S. and Clark, W. E., Jr.: Urethral reaction to foreign objects. J. Urol., 106: 227, 1971. 4. Engelhart, R. H., Bartone, F. F., Gardner, P. and Huston, J.: Urethral reaction to catheter materials in dogs. Invest. Urol., 16: 55, 1978. 5. Ruutu, M., Alfthan, 0., Heikkinen, L., Jarvinen, A., Lehtonen, T., Merikallio, E. and Standertskjold-Nordenstam, C. G.: "Epidemic" of acute urethral stricture after open-heart surgery. Letter to the Editor. Lancet, 1: 218, 1982. 6. Walsh, A.: Urethral strictures after open heart surgery. Letter to the Editor. Lancet, 1: 392, 1982. 7. Smith, J.M. and Neligan, M.: Urethral strictures after open heart surgery. Letter to the Editor. Lancet, 1: 392, 1982. 8. Fraser, I. D., Beatson, N. R. and McGinn, F. P.: Catheters anu postoperative urethral stricture. Letter to the Editor. Lancet, 1: 622, 1982. 9. Wesley-James, 0.: Catheters and postoperative urethral stricture. Letter to the Editor. Lancet, 1: 622, 1982.
0022-534 7/83/1306-1100$02.00/0 Vol. 130, December
THE JOURNAL OF UROLOGY
Copyright © 1983 by The Williams & Wilkins Co.
Printed in U.S.A.
URETHRAL STRICTURE AFTER CARDIOVASCULAR SURGERY, A RETROSPECTIVE AND A PROSPECTIVE STUDY A. ABDEL-HAKIM,* J. BERNSTEIN,t J. TEIJEIRA AND M. M. ELHILALI:j: From the Departments of Uro/,ogy and Cardiovascular Surgery, Centre Hospitalier Uniuersitaire, Sherbrooke, Quebec, Canada
ABSTRACT
In a review of our cases presenting with urethral stricture we noted a high incidence following cardiovascular surgery. A retrospective study was done, including 87 patients treated for urethral stricture and 304 undergoing open heart surgery during the same period, to search for a possible etiologic factor. A prospective study also was done on 98 patients subjected to cardiovascular surgery. Strictures developed in 17.5 per cent of 63 patients who had a urethral catheter placed for urinary diversion at operation compared to none of 35 who had a suprapubic cystocatheter. We believe that the urethral catheter is at least partly responsible for stricture formation. Associated factors, for example urethral ischemia, may be contributory. Stricture of the male urethra remains one of the difficult challenges facing the urologist. Iatrogenic traumatic strictures usually are the most common type. 1• 2 In a review of the cases of urethral stricture treated at our hospital during 2 years we found the incidence to be high following cardiovascular surgery, which was the second most common etiologic factor. A retrospective study was done to search for an acceptable etiology and a prospective study was done to verify our hypothesis. PATIENTS AND METHODS
Retrospective study. We diagnosed 87 patients with urethral stricture between July 1979 and July 1981. The 87 patients were distributed into 4 major groups: 1) after urologic surgery (34), 2) cardiovascular surgery (32), 3) medical departments (12) and 4) other surgical departments (9) (table 1). Mean patient age was 60 years. The youngest patients were those who underwent cardiovascular surgery (mean age 56 years). Of the patients 34 underwent urologic surgery, including 26 who had endoscopic procedures, mostly transurethral resection of the prostate (table 2). There was a history of recent cardiovascular surgery in 32 patients: open heart surgery with extracorporeal circulation in 21 (24.1 per cent) and peripheral vascular surgery in 11 (12.7 per cent). Patients undergoing cardiovascular surgery had 18F catheters, whereas those undergoing transurethral prostatic resection had 24F catheters. All catheters were made of latex and were purchased from the same manufacturer. Patients with possible urethral strictures were evaluated by uroflowmetry and retrograde urethrography. We analyzed 5 perioperative parameters in 304 patients operated upon for cardiovascular diseases between July 1979 and July 1981, namely pump time, heparin dose, protamine dose, degree of hypothermia and platelet count at the end of extracorporeal circulation. Prospective study. To verify the role of the urethral catheter in causing the strictures, a prospective double-blind paired study was done between August 1981 and August 1982. The patients were paired according to risk factors, including age, urinary symptoms, urinary tract infection, previous urethral manipulations, urethral trauma, physical examination, uroflowmetry and so forth. Each patient was assigned randomly to either urethral catheterization (68 patients) or a suprapubic Accepted for publication March 4, 1983.
* Current address: Urology Department, Cairo University, Cairo, Egypt.
t Current address: Urology Department, Toulouse University, Toulouse, France. :j:Requests for reprints: Department of Urology, Centre Hospitalier Universitaire, Sherbrooke, Quebec, Canada JlH 5N4.
cystocatheter (42 patients). The 18F latex Foley urethral catheters were inserted by the cardiac surgeon or a urologist in the operating room with the patient under general anesthesia. Cystocatheters were placed by a urologist the night before the operation with the patient under local anesthesia. The difference between the number of patients in each group is owing to the fact that not all patients could be paired. Patients were followed immediately postoperatively before leaving the hospital, at 6 weeks, and 3 and 9 months postoperatively by urologic history, examination, urinalysis, urine culture and uroflowmetry. The investigations of urethral strictures included retrograde urethrography and urethrocystoscopy. The statistical differences were compared using Student's t test. RESULTS
Retrospective study. Traumatic catheterization as an etiological factor for urethral stricture was excluded in this study by the fact that a urologist either supervised or practiced the catheterization in the operating room. Urinary infection was found in 6 patients (6.9 per cent): 3 after a cardiac operation, 2 after urologic manipulations and 1 after a vascular operation. The causative organisms were Escherichia coli in 3 patients, Pseudomonas in 2 and enterococci in 1. The average duration of catheterization was 1½ days after cardiovascular surgery compared to 1 day after transurethral resection. Urethral strictures were manifest an average of 16 days after cardiovascular surgery compared to an average of 23 days after transurethral resection. The difference was not significant. In 17 of 21 patients after cardiovascular surgery symptoms of urethral strictures occurred during the first 3 months postoperatively. Uroflowmetry was obstructive consistently, with a mean maximum flow of 9 ml. per second and a mean voiding time of 37 seconds, for a volume of 210 ml. The site of stricture similarly was distributed between the distal urethra in 47 patients and bulbar urethra in 49 (9 patients had multiple strictures). Five parameters in 304 patients who underwent open heart surgery during the same interval (July 1979 to July 1981) were compared and 21 patients suffered urethral strictures (table 3). No significant differences were found between the 2 groups for the parameters compared. Prospective study. Of the 110 patients studied we obtained adequate data on 98. Three patients died, 2 in the catheter group were lost to followup and 2 were excluded owing to difficult catheterization preoperatively. Also excluded were 5 patients from the cystocatheter group: 2 owing to severe hematuria postoperatively necessitating urethral catheterization and 3 because of postoperative urinary retention treated by urethral catheterization.
llOO
URETHRAL STRICTURE AFTER CARDIOVASCULAR SURGERY TABLE 1.
Patients with urethral strictures Mean Age (yrs.}
Urologic Cardiovascular Medicine Surgery Totals
TABLE 2.
No. Pts. (%}
63 56 58 64
34 32 12 9
60
8'i
(39.1) (36.8) (13.8) (10.3) (100)
Distribution of patients with urethral strictures after urologic procedures No.(%}
Endoscopic surgery: Transurethral resection of prostate Transurethral resection of vesical tumor Urethrolithotomy External sphincterotomy Cystoscopy Subtotal Retropublic prostatectomy Surgery for urethral trauma Partial cystectomy (vesical tumor} Radical nephrectomy Total
TABLE 3.
21 2 1 1 1
(24.1) (2.3) (1.1) (1.1) (1.1)
26 (29.9) 3 3 1 1
(3.4) (3.4) (1.1) (1.1)
34
Possible risk factors related to cardiovascular surgery With Strictures
No. pts.* Pump time (mins.} Heparin dose (mg.) Protamine dose (mg.} Hypothermia (C} Platelet count
21 98 320 409 29 118,315
Without Strictures 283 97 299 410
27 121,600
* Nonsignificant differences.
Of 63 patients with urethral catheters postoperatively 11 (17.5 per cent) suffered strictures compared to none of the cystocatheter group. Five patients with strictures were paired (45.5 per cent). One patient had postoperative urinary infection caused by E. coli, which was treated before discharge from the hospital. In 81.8 per cent of the patients symptoms of urethral stricture appeared in ~3 months. The site of stricture was meatal in 4 patients, penile in 4, bulbar in 6 and membranous in 2. Four patients had multiple strictures. DISCUSSION
Urethral reaction to foreign objects depends on many variables, such as catheter material, catheter size, concurrent trauma and/or infection, length of exposure and individual patient or animal variations. 8• 4 In animal experiments cellular reaction causing thrombosis in the submucosal area, and subsequent ischemic necrosis and scarring of the urethra were shown. 3 Urethral reaction to long-standing catheters was compared to bedsores. 1 In our series of urethral strictures following cardiovascular surgery traumatic catheterization as an etiological factor was excluded. A urologist either observed or practiced the catheterization immediately preoperatively in the operating room with the patient under general anesthesia. Urinary infection as a contributing factor does not seem to have a role in our series, since only 1 of those patients who suffered stricture had postoperative urinary infection that was cured before the patient was discharged from the hospital. The average duration of postoperative catheterization was 1.5 days and, therefore, prolonged catheterization as a contributing factor can be excluded. A contributing factor related to the cardiac surgery procedure itself was studied. We compared 5 parameters related to the cardiac surgery in 2 populations: 283 patients who did not have stricture and 21 undergoing the same procedure who did. No significant difference was found in the parameters studied.
1101
Since we were unable to find a classical urological factor or a cardiac factor, it was presumed that an abnormal urethral reaction to the catheter can explain the high incidence of urethral stricture in these patients. Two hypotheses were made: 1) a hypersensitivity of the urethra to the presence of the catheter (a tissue reaction can occur followed by fibrosis and stricture formation) and 2) an associated urethral ischemia to explain the fact that only some patients are at risk. These patients undergoing cardiovascular surgery frequently are suffering from marked peripheral vascular pathological conditions. The presence of a relative ischemia of the urethral wall in association with a foreign body and an exaggerated urethral response would explain the higher incidence of strictures in these patients. To verify the first hypothesis we performed a prospective double-blind paired study since August 1981. The patients were paired according to risk factors and each was assigned randomly to a urethral catheter or a cystocatheter. None of the patients with a cystocatheter suffered a stricture compared to an incidence of 17.5 per cent in the other group. We found similar observations in a review of the literature. In January 1982 Ruutu and associates noted an epidemic of urethral strictures following open heart surgery that led them to abandon urethral catheterization and to place cystocatheters routinely. 5 Soon after, similar experiences were reported. Walsh,6 and Smith and Neligan 7 explained the incidence as related to the type of urethral lubricant used. Fraser and associates explained the pathological condition as related to the size of the catheter and to chemical irritation caused by starch powder from surgeon gloves contaminating the catheters. 8 Wesley-James noted a 50 per cent incidence of urethral stricture after open heart surgery and explained it as secondary to the use of a cheaper type of latex catheter. 9 However, in our series the same type of catheters, lubricant and surgical gloves is used for all patients undergoing urethral catheterization for any cause. The incidence of urethral strictures after cardiovascular surgery is much higher than the incidence in patients even undergoing transurethral resection, in whom more urethral trauma is inevitable. A larger caliber catheter is applied using the same lubricant and same catheter material for almost the same duration. Routine cystocatheter urinary diversion before open heart surgery is not without risk in an anticoagulated patient. We believe that the urethral catheter is at least partly responsible for the high incidence of urethral stricture following cardiovascular surgery. Our study is being extended to verify the second hypothesis of possible urethral ischemia, in an attempt to identify the patient at risk. REFERENCES
1. Blandy, J.P.: Urethral stricture. Postgrad. Med. J., 56: 383, 1980. 2. Walther, P. C., Parsons, C. L. and Schmidt, J. D.: Direct vision internal urethrotomy in the management of urethral strictures. J. Urol., 123: 497, 1980. 3. Painter, M. P., Borski, A. A., Trevino, G. S. and Clark, W. E., Jr.: Urethral reaction to foreign objects. J. Urol., 106: 227, 1971. 4. Engelhart, R. H., Bartone, F. F., Gardner, P. and Huston, J.: Urethral reaction to catheter materials in dogs. Invest. Urol., 16: 55, 1978. 5. Ruutu, M., Alfthan, 0., Heikkinen, L., Jarvinen, A., Lehtonen, T., Merikallio, E. and Standertskjold-Nordenstam, C. G.: "Epidemic" of acute urethral stricture after open-heart surgery. Letter to the Editor. Lancet, 1: 218, 1982. 6. Walsh, A.: Urethral strictures after open heart surgery. Letter to the Editor. Lancet, 1: 392, 1982. 7. Smith, J.M. and Neligan, M.: Urethral strictures after open heart surgery. Letter to the Editor. Lancet, 1: 392, 1982. 8. Fraser, I. D., Beatson, N. R. and McGinn, F. P.: Catheters anu postoperative urethral stricture. Letter to the Editor. Lancet, 1: 622, 1982. 9. Wesley-James, 0.: Catheters and postoperative urethral stricture. Letter to the Editor. Lancet, 1: 622, 1982.