The mechanisms of continence in the Indiana pouch: a video-urodynamic study

The ileocecal reservoir (Indiana pouch) is a large volume, low pressure continent reservoir well suited for urinary diversion. The mechanism of continence is believed to be the result of several factors, including the natural ileocecal valve resistance, resistance produced by the plication of the ileal segment and normal peristalsis of the ileum. We report the results of a video-urodynamic study in patients with an Indiana pouch, aimed at establishing the factors that contribute to continence and their relative significance. Video-urodynamic studies clearly demonstrate that continence in this type of urinary reservoir is dependent upon a synergism of the aforementioned factors in combination with the low intraluminal pressure of the detubularized bowel. Video-urodynamic studies offer an objective demonstration of the reservoir dynamics and its continence mechanisms, and provide an insight into the possible etiology of incontinence. Such studies also offer an objective means for critical comparison of the different continent urinary reservoirs.     

The Kock continent ileal urinary reservoir: surgical technic and clinical results

From July 1985 through January 1986, 43 patients underwent urinary diversion that included creation of a continent reservoir from an ileal segment, according to the method described originally by Kock. An important modification included removal of a narrow strip of mesentery for 8 cm along the afferent and efferent limbs of the pouch to allow adequate ileal intussusception and fixation of the nipple valves to prevent reflux and to ensure continence. A strip of PGA mesh serves as a collar to fix the afferent-efferent limb to the pouch once the intussusception technique has been accomplished. The use of a narrow Marlex strip allows fixation to the abdominal wall both lateral and medial to the stoma site (insert). This strip is important in preventing a parastomal hernia and helps fix the continence valve mechanism to the posterior abdominal wall. Previous urinary diversion was by ureterosigmoidostomy in 2 patients, standard ileal conduit in 8 and chronic dialysis after nephrectomy of solitary kidney and cystectomy in 1. A total of 32 patients underwent simultaneous anterior exenteration or radical cystectomy for pelvic malignancy. There were 4 postoperative deaths and early complications occurred in one patient. Late complications occurred in only 3 patients: they required reoperation and revision of the continence valve mechanism. The end result in 39 of 43 patients has been an overwhelming success. Patients perform self-catheterization every 4 to 6 hours during the day and once at night for volumes ranging up to 1,400 cc. Serum electolytes have remained normal in all patients. X-ray of the Kock pouch have shown no evidence of reflux, and all excretory urograms have demonstrated either normal upper tracts without obstruction or improvement in patients with preoperative hydronephrosis. Although preliminary, this clinical trial suggests that the quality of life for patients considered previously to be candidates for cutaneous diversion can be improved markedly by a modified Kock continent ileal reservoir. During the same time, 21 patients out of 278 patients who underwent creation of a Kock continent ileal urinary reservoir since August 1982, underwent revision of Kock pouch. Two of those required subsequent reoperation and revision of the continence valve mechanism. The end result in all patients has been an overwhelming success.     

Continence mechanisms of the Indiana pouch

The Indiana pouch is a large capacity, lowpressure continent urinary reservoir. The mechanism of continence in the Indiana pouch has been shown to be the result of several factors, including the natural resistance of the ileocecal valve, resistance produced by the plication or tapering of the ileal efferent limb, and peristalsis of the ileum. Continence in urinary diversions is reviewed with special emphasis on the mechanisms of continence in the Indiana pouch.     

Continent small-intestine reservoir construction: a tapered intussusceptum promotes sustained continence

Summary Developed for the study of dialysis in the continent jejunal reservoir (CJR), a novel, uncomplicated approach to achieve continence in construction of a small-bowel reservoir is presented. We utilize a technique of constructing a continent nipple valve, which entails the reduction or tapering of the intussusceptum prior to invagination into the reservoir. We have thus far performed the procedure successfully in 21 dogs. All animals have achieved absolute continence. Complications have occurred in two animals, neither complication involving the nipple valve. Pressure-volume cytometry in nine animals demonstrates continence in the awake animal at pressures of up to 40 cmH₂O (volumes being limited by animal discomfort due to reservoir distention). In postmortem studies, reservoir capacities of >1000 ml and pressures of >70 cmH₂O have been attained without loss of continence or prolapse of the nipple valve. Continence is sustained even when the reservoir and nipple valve are subjected to high intraluminal pressures. Incorporating a tapered intussusceptum, the continent reservoir provides absolute continence without the use of cumbersome mesh fixation or lithotropic intraluminal staples.     

Indiana continent urinary reservoir: report of 15 cases

Over the last several years, internal reservoir type urinary diversions have become popular. We have already performed Kock continent ileal reservoir for urinary diversion in more than 80 patients. The experience with the Kock pouch prompted us to try a new form of continent urinary reservoir originally reported by Indiana University group. The Indiana pouch is a composite structure using ileum and cecum. The antireflux mechanism is provided with tunneled ureteral implantation along the tenia of the cecum. Plication of the terminal ileal segment along with the ileocecal valve maintains urinary continence. The tubular configuration of the cecum is completely disrupted with either an ileal patch or Heineke-Mikulicz re-configuration to construct a low pressure reservoir. Between October, 1987 and September, 1988, we performed Indiana continent urinary diversion in 15 cases: 13 males and 2 females, from 47 to 73 years old (mean age 61.3 years), 14 bladder cancer patients and 1 bladder sarcoma patient. The initial 8 patients underwent Heineke-Mikulicz type operation and the subsequent 7 patients ileal patch-type operation. Median followup has been 7 months. There were no major early complications but one postoperative death with blood transfusion related graft versus host disease (GVHD). The late complication occurred in 2 patients: 1 stenosis of the pouch due to insufficient detubularization of the cecum and 1 pyelonephritis required no admission. Serum electrolytes and vitamin B12 remained normal in all patients. Patients perform self-catheterization every 3-5 hours during the day and 0-2 times at night for volumes ranging up to 800 ml. With regard to volume capacity and pressure characteristics, the ileal patch type reservoir seemed to be superior to the Heineke-Mikulicz type pouch as a receptacle for urine. Over-all, 12 of 14 patients (86 per cent) have acceptable continence. The remaining 2 patients have significant daytime leakage requiring pads or a cutaneous bag. Followup examination with excretory urography showed no upper tract obstruction and X-rays of the pouch showed no reflux. Indiana pouch is a relatively simple continent urinary reservoir, since the steps of this technique already are familiar to urologists. It may be an alternative form of continent urinary diversion.     

Kock pouch and S bladder: 2 different ways of lower urinary tract reconstruction

Many attempts have been made to develop a continent form of urinary diversion. Encouraging results have been obtained with the Kock pouch, which offers a low pressure reservoir, safe reflux protection and a reliable continent abdominal wall stoma. If urethral function could be saved without risk, anastomosis of a bowel bladder to the urethral stump is more favorable as far as cosmetics and continence are concerned. The S bladder, developed on the basis of the S pouch, is conceptualized to be a complete replacement of the lower urinary tract that offers a low pressure reservoir, safe antireflux mechanisms, continence and voiding per urethram with abdominal straining. We treated 78 patients with continent urinary diversion (Kock pouch in 46 and S bladder in 32). Continence was achieved in 87% of the patients treated with a Kock pouch, while 93.8% were continent in the S bladder group. In an effort to achieve continence day and night 43.8% of the patients treated with an S bladder required an artificial sphincter. The over-all complication rate (12.5 compared to 41.8%) and the operative complication rate (6.3 compared to 23.9%) were significantly lower in patients treated with the S bladder. Emptying by abdominal straining was possible in all patients with an S bladder. Residuals were less than 50 cc, even in patients with an artificial sphincter.     

Clinical experience with the Kock continent ileal urinary reservoir

From May 1985 through July 1987, 22 patients underwent Kock continent ileal reservoir for urinary diversion. There were 19 males and 3 females, between 38 and 82 years old (mean age 63.1 years). A one-stage radical cystectomy and Kock pouch construction were performed in 21 patients. One patients was converted from standard ileal conduit to this new reservoir. The keys to success of the Kock pouch are creation and maintenance of the nipple valve to prevent reflux and to ensure continence. Mesenteric fat is removed with CUSA for 8 cm along the afferent-efferent limbs of the pouch and exclusion of mesentery is limited for only 3-4 cm. This important modification will ensure adequate ileal intussusception and vascular supply to the valves. To prevent eversion and prolapse, the nipple valve is anchored to the wall of reservoir. A strip of sauvage filamentous Dacron serves as a collar to fix the afferent-efferent limbs to the pouch. There were 2 postoperative deaths and two major early complication: 1 acute renal failure and 1 intestinal fistula, both of which were treated conservatively. Late complications occurred in 6 patients. Of these 6 patients, 1 required reoperation and revision of the continence valve mechanism and 1 required hospitalization for entero-pouch fistula. Serum electrolytes and vitamin B12 remained normal in all patients. Patients perform self-catheterization every 4-6 hours during the day and once at night for volumes ranging up to 1,000 ml. The end result in 19 of 20 patients was excellent.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical experience with the Kock continent ileal reservoir for urinary diversion

From August 1982 through January 1984, 51 patients underwent urinary diversion that included creation of a continent reservoir from an ileal segment, according to the method described originally by Kock. An important modification included removal of a narrow strip of mesentery for 8 cm. along the afferent and efferent limbs of the pouch to allow adequate ileal intussusception, and fixation to prevent reflux and to ensure continence. Previous urinary diversion was by ureterosigmoidostomy in 3 patients, standard ileal conduit in 7 and suprapubic cystotomy in 1. A total of 39 patients underwent simultaneous anterior exenteration for pelvic malignancy. There was 1 postoperative death and early complications occurred in 10 patients. Of these 10 patients 4 required reoperation: 2 for drainage of a pelvic abscess, 1 for conversion to a standard ileal conduit and 1 for bleeding. Late complications occurred in only 8 patients: 5 required reoperation and revision of the continence valve mechanism, and 3 required hospitalization for brief episodes of pyelonephritis. The end result in 49 of 50 patients has been an overwhelming success. Patients perform self-catheterization every 4 to 6 hours during the day and once at night for volumes ranging up to 1,400 cc. Serum electrolytes have remained normal and hyperchloremic acidosis has been encountered in only 1 patient who had had compromised renal function preoperatively with hyperchloremic acidosis as a result of previous ureterosigmoidostomy. X-rays of the Kock pouch have shown evidence of reflux in only 1 patient, and all excretory urograms have demonstrated either normal upper tracts without obstruction or improvement in patients with preoperative hydronephrosis. Although preliminary, this clinical trial suggests that the quality of life for patients considered previously to be candidates for cutaneous diversion can be improved markedly by a modified Kock continent ileal reservoir.     

Modified Indiana pouch

The modified continent Indiana pouch is based upon the terminal 8 to 12 cm. of ileum and 26 to 30 cm. of right colon. Our modifications include complete detubularization of the colonic segment with an easier appendectomy, a transcolonic ureteral reimplantation that is technically simple and reinforced plication of the ileocecal junction. This procedure was performed in 70 patients (ages 27 to 85 years) with followup ranging between 3 and 24 months. There have been 5 hospitalizations for urinary tract infections or gastrointestinal complications. Open surgical revision (4%) has been necessary for incontinence in 1 case, for a redundant ileal limb and difficult catheterization in 1, and for ureteral stenosis in the mid portion of the left ureter in 1. A revision procedure is pending for inadequate reservoir volume. Endoscopic meatotomy of ureterocolonic junction strictures has been necessary in 2 cases. All patients are continent day and night with easy catheterization of volumes ranging between 400 and 800 cc. The modified Indiana pouch should be considered for any patient requiring cutaneous urinary diversion because of a low complication and revision rate, and an excellent continence rate.     

Indiana continent urinary reservoir

Cecoileal reservoirs were created in 29 patients. Tunneled ureteral implantations along the tenia of the cecum provided the antireflux mechanism. Plication or tapering of the terminal ileal segment along with the ileocecal valve provided the continence mechanism. The tubular configuration of the cecum was disrupted with either an ileal or sigmoid patch, or it was re-configured in a Heineke-Mikulicz type of closure to avoid bolus (unit) contractions. Short-term followup examination with excretory urography showed no upper tract obstruction. X-rays of the pouch showed no reflux and interviews revealed satisfactory continence in 93 per cent of the patients.     

The modified Indiana pouch

The modified continent Indiana pouch is based upon the terminal 8-12 cm of ileum and 26-28 cm of right colon. Our modifications include complete detubularization of the colonic segment with an easier appendectomy, a transcolonic ureteral reimplantation that is technically simple, and reinforced plication of the ileocecal junction. This procedure was performed in 70 patients (ages 27-85 years) with follow-up ranging between 3-24 months. There have been five hospitalizations for urinary tract infections or gastrointestinal complications. Three open surgical revisions (4%) have been necessary: one for incontinence, one for a redundant ileal limb and difficult catheterization and one for ureteral stenosis in the mid-portion of the left ureter. One revision is pending for inadequate reservoir volume. Two endoscopic meatotomies of ureterocolonic junction strictures have been necessary. All patients are continent day and night, enjoy easy catheterization of volumes ranging between 400 and 800 cc. The modified Indiana pouch should be considered for any patient requiring cutaneous urinary diversion because of a low complication and revision rate and an excellent continence rate.     

Replacement of the bladder by the urethral Kock pouch: functional results, urodynamics and radiological features

After cystoprostatectomy for cancer of the bladder 43 men were provided with a detubularized, low pressure ileal reservoir (Kock pouch) connected to the urethra. Reflux was prevented by an intussusception valve. There was no operative mortality and few early complications. At followup the mean postoperative observation time was 13 months, with a range of 5 to 20 months. Late complications included manifestations of local tumor recurrence or distant metastases in 9 patients within 6 months postoperatively, which made adequate functional evaluation impossible. In 18 patients reflux to the upper urinary tract due to eversion or sliding of the antireflux valve occurred at various postoperative intervals. In 16 of these patients incontinence developed as a consequence of the reflux. Surgical correction of the failing antireflux valve restored reflux prevention and continence. Within 3 to 6 months the capacity of the reservoirs had reached an ultimate volume of approximately 600 ml. Pressure waves exceeding 40 cm. water seldom occurred in the mature reservoirs and then only at high filling volumes. The mean urethral resting resistance to flow was 64 cm. water. The configuration and function of the upper urinary tract improved or stabilized postoperatively. Of 34 evaluable patients 30 were continent during the day with a voiding frequency of 3 to 5 times and dry at night with a frequency of 0 to 2.     

A seromuscular stripping method to create a nipple valve without metal stapling for continent urinary reservoir

Urinary continence with a Kock or Mainz pouch is achieved by a nipple valve of the invaginated ileum which is usually fixed with metal staples. However, metal staples can cause various complications as a foreign body. The seromuscular stripping method, a new technique to create a nipple valve, was applied to 17 patients with bladder cancer in the construction of a continent urinary reservoir by the ileocolonic pouch (Mainz pouch). Metal staples were not used. The results were satisfactory except for 2 patients who became incontinent because of prolapse of the nipple in one and insufficient valve function due to ischemic change of the nipple valve in the other. Histology of the nipple valve from an autopsy case showed a good double layer nipple valve that functioned well to preserve continence.     

Evaluation of flap valve as an alternative continence mechanism in the Florida pouch

OBJECTIVES: To evaluate urodynamic findings in a successful flap valve (FV) continence mechanism in association with a continent colonic urinary reservoir (Florida pouch) and to compare the urodynamic findings of the FV mechanism with the doubly plicated (PI) standard anti-incontinence segment in the same reservoir. METHODS: Thirteen patients who successfully received the Florida pouch between 1988 and 1996 agreed to undergo urodynamic evaluation as part of a pilot study. Eight patients had a PI continence mechanism and a mean time from surgery of 51 months; 5 had a FV continence mechanism and a mean time from surgery of 14 months. Enterocystometry was performed with a trans-stomal Bard triple channel 7F catheter. Volume and pressure at first desire to empty (VFDE, PFDE), as well as maximal enterocystometric capacity and pressure (VMEC, PMEC), were recorded. Maximal outlet pressure (MOP) was recorded using the catheter withdrawal technique. RESULTS: PI and FV groups demonstrated the following mean values respectively: VFDE, 692.7 and 403 mL; PFDE, 19.5 and 19.2 cm H2O; VMEC, 876.5 and 515 mL; PMEC, 25.9 and 24.6 cm H2O; MOP, 57.5 and 51.2 cm H2O (reservoir empty) and 50.5 and 52.6 cm H2O (reservoir full); and functional length of outlet, 24.3 and 24.6 cm. MOP measurement demonstrated greater variability in the PI than in the FV group. CONCLUSIONS: Urodynamic comparison of these mechanisms reveals that MOP measurement was closer to the mean among FV than PI patients. In addition, the mean VFDE (692.7 mL for PI versus 403 mL for FV, P < 0.05) and the mean VMEC (876.5 mL for PI versus 515 mL for FV, P < 0.05) were significantly less in the FV group. Lower VMEC and less variability in MOP indicate that continence may be more dependent on MOP in the FV mechanism. A longer follow-up time and a larger number of patients will be of assistance in clarifying these findings.     

Key factors influencing bowel function after ileal W-pouch anal anastomosis: A spectral analysis of W-pouch motor activity

Restorative proctocolectomy with ileal pouch anal anastomosis (IPAA) has become the standard surgical procedure for ulcerative colitis (UC). The purpose of this study was to determine which factors are important to achieve good anal continence after IPAA in terms of the motor activity and pressure–volume relationship. A total of 17 patients with UC who underwent IPAA were evaluated. The internal ileal pouch pressure was transanally measured with and without volume-loading of the pouch which induces the urge to evacuate. The maximum tolerable volume (MTV), first urge volume (FUV), and ileal pouch compliance were calculated and the internal ileal pouch pressure records were subjected to spectral analysis for intensive evaluation of the intraluminal pressure waves. The FUV, correlation of the compliance of the FUV with MTV, and the remaining volume up to the MTV (RVMTV) were analyzed. Compliance of the FUV was significantly correlated with the RVMTV (r = 0.736, P < 0.01). The frequency of the phasic waves in the pouch decreased with length of follow up, reflecting improved function (r = −0.588, P < 0.05). The findings of this intensive analysis of manometric measurement indicate that the key factors in postoperative pouch function are RVMTV and the frequency of phasic waves in the W-pouch. Received: May 6, 1999 / Accepted: May 30, 2000     

Intestinal implantation of an artificial sphincter]

In order to restore anal sphincteric function, artificial AMS sphincter was used with his 3 components: the peri-intestinal cuff giving anal sphincter tone, the pump used for active opening and the pressure regulating balloon. In the same fashion a continent valve may be created on an intestinal segment as a part of a reconstructed bladder. In this case the pump may be replace by a subcutaneous port allowing fluid injection to adjust volume and pressure in the cuff. Two patients with fecal incontinence related to sequela of a high imperforate anus syndrome were implanted. Follow-up is greater than 1 year with normal continence in the day for the first case (degree 2) and continence day and night in the second case. Artificial valve has been implanted in seven cases of neobladder pouch (or related situations), with in 4 cases very good results and in 3 cases a failure (Follow-up 3-36 months).     

Improved results with continent ileostomy.

The objective of this study was to determine if recent technical modifications have improved our results with continent ileostomy (Kock pouch). The modifications were that the valve of the pouch was made at least 5 cm in length and was anchored with specially placed, nonabsorbable sutures or staples. The pouch was drained continuously for the first four postoperative weeks, after which it was only gradually allowed to expand. Results from our first 149 patients were compared to those from our last 150 patients, in whom the modified approach was used. The age, sex, indications for operation and types of operation were similar in the early and late groups. No postoperative deaths occurred, and the incidence of continence at dismissal from hospital was near 100% in both groups. However, 15 pouches were excised in the early group as opposed to only five in the late group (p < 0.01). Moreover, the need for revision of the valve by one year was 43% in the early group but only 22% in the late group (p < 0.001). Long-term follow-up showed that complete continence was present in 60% of patients in the early group and 75% of patients in the later group (p < 0.05), although only about 5% of patients in either group wore an ileostomy bag. We concluded that recent technical changes have improved the results after continent ileostomy.     

Clinical experience of Kock pouch continent urinary diversion

Kock continent ileal reservoir for urinary diversion was performed in 53 patients with invasive bladder cancer (52) or neurogenic bladder (1). The postoperative follow-up period was from six to thirty-nine months. The clinical results showed no metabolic disturbance of blood electrolytes or acidity. Prolapse of efferent nipple valve developed in 4 patients (7.6%); and 2 underwent revisional surgery with a good result. Another 4 patients (7.6%) suffered from poor continence and relatively frequent catheterization to empty the pouch was necessary to prevent urine leakage through the stoma. Urodynamic study of the Kock pouch in these 4 patients showed a short functional nipple valve length and small pouch capacity. The other 45 patients (84.8%) had good continence. Urodynamic study of the pouch in 20 patients showed low pressure (mean of 13.3 cm H2O) in the pouch and high pressure (mean of 72.1 cm H2O) at the efferent nipple valve. Three patients had unilateral hydronephrosis in the follow-up intravenous urography. Corrective surgery for stenosis at the right ureteroileal anastomosis was done in 1 patient with normalization of the upper urinary tract afterward. The other 2 patients were managed by close observation for the mild hydronephrosis. Symptomatic bacteriuria developed in only 3 patients (5.7%) and responded well to antibiotic management. Reservoirography demonstrated no reflux into the upper urinary tract in all the follow-up patients. There was no significant change of the renal function at twenty-four months after operation detected by radionuclide (131I-Hippuran) renal functional study. All patients were satisfied with Kock urinary diversion.     

三种可控性结肠贮尿囊的效果比较

目的　寻求理想的可控性尿流改道术式。　方法　 3 7例患者 ,采用去带盲升结肠贮尿囊者 13例 ,采用penn贮尿囊者 11例 ,采用改良Indiana贮尿囊者 13例。其中 3 5例行尿动力学检查 ,对不同贮尿囊的容量和压力结果进行比较。　结果　去带盲升结肠尿囊组 3个月时的容量和压力与另 2组贮尿囊的结果比较差异有非常显著性意义 (P <0 .0 1) ,3种贮尿囊的容量、囊内压均可随时间的推移得到改善 ,术后 12个月时其容量之间的差异无显著性意义 (P >0 .0 5 )。Penn贮尿囊能有效降低收缩压。阑尾作输出道者均可获得良好的尿控。　结论　Penn贮尿囊和改良Indiana贮尿囊是较理想的可控性尿流改道术式 ,去带盲升结肠贮尿囊有手术操作相对简单的优点     

Evaluation of the long-term effectiveness of extraluminal and intraluminal vasodilators in an in vitro porcine model of arterial graft spasm

Objective.

Postoperative graft spasm is a concern when arterial conduits are used because there may be insufficient arterial graft flow. Intraoperatively, vasodilators are used to increase flow and prevent spasm, but little is known about their duration of effectiveness.

Methods.

To examine this we attached porcine gastroepiploic and internal thoracic arteries (GEA, n=48; ITA, n=24, 10–12 cm long) to a computer-controlled perfusion system (constant inflow pressure 80 mmHg) with a fixed outflow resistance. Norepinephrine (10⁻⁹ – 10⁻⁵ M) was incrementally added to the perfusate at baseline (B), then immediately (h+0) and 2 h (h+2) after the vessels were treated with 30 min of extraluminal or intraluminal nitroglycerin, nitroprusside, verapamil or papaverine.

Results.

At (B), norepinephrine caused a dose-dependent decrease in flow in both the ITAs and GEAs. In the ITAs, at (h+0), both extraluminal and intraluminal papaverine and, to a lesser extent nitroprusside, increased initial flow and decreased graft sensitivity to norepinephrine. At (h+2), only extraluminal papaverine sustained this maximal effect (ED₅₀ for extraluminal papaverine at (B) 2.6 E⁻⁷ vs (h+2) 1.3 E⁻⁶, P=0.01). For the GEAs, at (h+0), both extraluminal and intraluminal verapamil, papaverine, nitroprusside and nitroglycerin attenuated flow reduction due to norepinephrine. At (h+2), only extraluminal papaverine, extraluminal verapamil and intraluminal verapamil were effective in preventing norepinephrine-induced spasm (ED₅₀ for extraluminal papaverine at (B) 1.0 E⁻⁷ vs (h+2) 6.4 E⁻⁶ (P=0.004); extraluminal verapamil at (B) 1.2 E⁻⁷ vs (h+2) 4.0 E⁻⁶; intraluminal verapamil at (B) 5.8 E⁻⁷ vs (h+2) 5.7 E⁻⁶, P=0.005).

Conclusion.

Verapamil-and papaverine-treated arteries have a greater duration of efficacy in resisting spasm than arteries treated with nitroglycerin and nitroprusside. In the ITA, extraluminal administration of papaverine is most efficacious, possibly due to the prolonged exposure afforded by this route of administration. The effects of verapamil and papaverine are more prolonged in the GEA when administered extraluminally, potentially due to absorption in the perivascular fat-pad and subsequent slow release. The results of this study suggest that extraluminally administered verapamil and papaverine appear to be the preferred vasodilators for preventing arterial graft spasm in the postoperative period. This may be especially important when multiple arterial grafts are used.