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Technical Innovation |
1 Department of Medical Imaging, University of Toronto, University Health
Network and Mt. Sinai Hospital University, 200 Elizabeth St., Toronto, ON,
Canada M5G 2N2.
2 Toronto General Hospital, 200 Elizabeth St., Toronto, ON, Canada M5G
2C4.
3 Department of Radiology, St. Joseph Health Care, Hamilton, ON, Canada L8N
4A6.
Received January 29, 2004;
accepted after revision June 7, 2004.
Address correspondence to C. S. Ho.
Abstract
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CONCLUSION. Permanent access to self-expandable biliary stent provided a safe and effective means for timely reintervention in stent occlusion with acceptable stent patency.
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The concept of retaining permanent access to the biliary endoprosthesis is not new. When plastic stents were introduced, some stents had strings attaching the proximal end to the skin surface for eventual access. In this article, we describe a new approach that establishes permanent access to a metallic stent at the time of insertion. This allows early detection of stent occlusion and safe intervention if necessary. With this access, stent occlusion can be managed on an outpatient basis, without the need to perform a new percutaneous biliary drainage procedure and its associated risks. We report our initial results with this new approach.
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The study group was composed of 14 men and 14 women (mean age, 68 years; median age, 70 years; range, 46–85 years). The causes of biliary obstruction were pancreatic adenocarcinoma (n = 7), extrahepatic cholangiocarcinoma (n = 10), duodenal carcinoma (n = 3), metastatic gastric adenocarcinoma (n = 2), metastatic esophageal cancer (n = 1), metastatic colonic carcinoma (n = 1), metastatic breast carcinoma (n = 2), metastatic paraganglioma (n = 1), and metastatic ovarian carcinoma (n = 1).
All eight patients with metastatic disease had their primary malignancy diagnosed at surgery or biopsy. Endoscopic biopsy findings were positive in three patients with duodenal malignancy. Five patients with pancreatic adenocarcinoma or cholangiocarcinoma underwent laparotomy and were found to have inoperable malignancy. Diagnosis in 11 patients with malignancy of the pancreas or bile duct was based on clinical grounds, and follow-up indicated that these patients had died from their disease. The remaining one patient was alive at the end of the study period and had a gcholangiocarcinoma at the hilar region (Klatskin's tumor). All patients had undergone endoscopic stent placement that was unsuccessful either from technical failure or from lack of endoscopic access due to previous surgery. Percutaneous insertion of an internal–external biliary drainage catheter was performed for relief of obstructive jaundice. Metallic stents were inserted later because of frequent catheter-related problems such as blockage, displacement, or dislodgement.
For permanent access to be established, a small 4-French Kumpe catheter (Kumpe, Cook) was left across the stent at the time of metallic stent placement (Fig. 1). It was fixed at the skin with a 20 x 10 x 3 mm low-profile catheter fixation device (Fig. 2A, 2B). The method of application of this device has been described previously [9].
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Patients were asked to return for follow-up if they experienced bile leakage around the insertion site, fever, chills, or recurrent jaundice. In such an event, the low-profile device was removed and a 0.035-inch guidewire was inserted through the access catheter, which was later removed. An 8-French angiography introducer was inserted over the guidewire to access the bile duct, and contrast material was injected through its sidearm for cholangiography. If stent occlusion was found, a second metallic stent or a biliary drainage catheter was inserted over the guidewire to relieve biliary reobstruction. If no obstruction was found, a new 4-French Kumpe catheter was inserted over the guidewire and was left in place for permanent access as was done earlier.
Data were collected with regard to complications of stent insertion, frequency of percutaneous biliary drainage, catheter blockage before stent placement, frequency of stent occlusion, duration of stent patency, frequency of cholangitis or hospitalization, and overall survival. Kaplan-Meier analysis was used to assess survival time and stent patency. The number of stent reinterventions was recorded. Patients were followed up until death or until the end of the study period.
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Fifteen (54%) of the 28 patients required a total of 50 diagnostic and interventional procedures via the access catheter or its subsequent replacement. Four of the five patients with Klatskin's tumors had percutaneous biliary drainage catheters changed eight times.
The access catheter or its replacement was used once in three patients, twice in two, thrice in five, four times in three, seven times in one, and nine times in another patient. The procedures included diagnostic cholangiography in 15 patients, additional Wallstent insertions in 10, and placement of an internal–external percutaneous biliary drainage catheter in 25. A total of 38 Wallstents were inserted in the 28 patients. There was a statistically significant decrease in the frequency of reinterventions after metallic stent insertion. The monthly reintervention rate before and after metallic stent insertion was 1.44 and 0.20, respectively (exact binomial test, p < 0.0001).
The mean monthly cholangitis rate before and after metallic stent insertion was 0.22 and 0.06, respectively (exact binomial test, p = 0.0636). This finding is not statistically significant.
Eleven patients in our group were admitted to the hospital for treatment of sepsis, seven before and four after insertion of the metallic stent. No patient was admitted to the ICU for sepsis. All patients accepted the access catheter as part of their palliative treatment; none opted for its removal.
The 30-day mortality rate after stent insertion was 21.4% (6/28 patients) with no procedure-related deaths or immediate morbidity. Death was caused by advanced disease with stents that remained patent. A delayed complication requiring surgery occurred in one patient (3.6%) 11 months after insertion of a Wallstent with an access catheter. He was found to have biliary peritonitis due to leakage from a cracked access catheter. He underwent laparotomy and recovered fully. He went on to live for another 24 months after laparotomy and had nine reinterventions. Four patients (14%) developed cholangitis due to stent occlusion and were admitted to the hospital for antibiotic treatment and biliary reintervention. Two patients with significant ascites experienced leakage of ascitic fluid at the insertion site. Their Kumpe catheter was removed, and the leakage stopped. In two other patients, the Kumpe catheter fell out without any complications.
At the time of writing, all patients except one had died. This was confirmed by follow-up telephone calls to the families of all patients whose last clinical records indicated they were still alive. The cause of death could not be ascertained but was thought to be due to advanced disease. The one living patient had a cholangiocarcinoma, and a second stent was inserted 4 months later because of stent occlusion. She remained well with no signs of reobstruction. The median duration of stent patency was 10 months (mean, 8.8 months; range, 1–15 months). Patency rates for the metallic stents at 1, 3, 6, and 12 months were 96.2%, 81%, 56.8%, and 36%, respectively (Kaplan-Meier analysis).
The median duration of survival from the time of diagnosis was 18 months (mean, 23.1 months; range, 3–43 months) and from the time of metallic stent placement was 15 months (mean, 16.8 months; range, 1–27 months). Kaplan-Meier curves for the patient survival duration and stent patency duration are given in Figure 3A, 3B, 3C.
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When reintervention is considered, its difficulty and risks must be weighed against its benefits. From our experience, placement of a new percutaneous biliary drainage catheter is more risky than a catheter exchange. In our 234 patients with new percutaneous biliary drainage catheters, major bleeding requiring angiography occurred in seven patients (3%), but none was caused by catheter exchange. Therefore, placement of a new biliary drainage catheter is less likely to be performed in a very sick patient with an occluded stent. In this regard, the permanent access simplifies biliary reintervention and may have benefited some of our patients who otherwise would have been considered unsuitable for reintervention.
We believe that establishing permanent biliary access offers another benefit by signaling early stent occlusion. We found that bile leakage around the insertion site frequently occurred when a stent had become occluded but before jaundice or cholangitis manifested clinically. This theory was based on our cholangiography confirmation of stent occlusion in these patients and the fact that bile leakage stopped after the insertion of another stent or a biliary drainage catheter.
By reporting bile leakage at the insertion site, our patients were able to seek and obtain timely medical treatment. Assessment and, if necessary, treatment were simple and easily accomplished on an outpatient basis. Only four patients were admitted to the hospital for significant sepsis due to biliary reobstruction; all others were managed as outpatients. We believe the sooner stent occlusion is diagnosed and treated, the less likely that it will lead to severe or life-threatening cholangitis. In patients with slow-growing tumors, timely relief of reobstruction may prolong life by preventing premature death from severe sepsis.
We found that the duration of patency for our metallic stents with permanent access is acceptable. The patency duration of the biliary Wallstent in our study (median, 10 months; mean, 8.8 months) is close to the longest patency previously published, with the median patency ranging from 135 days to 360 days (Table 1). This finding should not be surprising because stent occlusion is due to tumor ingrowth or overgrowth rather than to sludge formation [10] as in plastic stents or internal–external biliary drainage catheters. There is no evidence that tumor over-growth or ingrowth is affected by the presence of a small catheter.
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The median survival of 15 months (455 days) after stent insertion is much longer than those reported in the literature, which range from 95 to 246 days (Table 1). One explanation for the longer survival time is that our patients were treated at an earlier stage of their disease; however, we had no evidence to substantiate this. Another possibility is that our patients had less aggressive malignancies than the patients in other reports. For example, cholangiocarcinoma grows more slowly than cancer of the pancreas and may have a positive effect on overall survival. In our study group, only 10 patients (36%) had cholangiocarcinoma and its positive effect on survival was offset by 15 patients (54%) with either metastatic or pancreatic neoplasms. However, we suspect that the permanent access also may have played a positive role, at least in some patients, by allowing earlier detection and safer reintervention of biliary reobstruction. This speculation requires confirmation with more objective evidence.
The permanent-access catheter caused one morbidity and was involved in four minor complications. One patient developed biliary peritonitis 13 months after insertion and was found at laparotomy to have a cracked access catheter. This finding was an isolated, although significant, one. We speculate that the catheter had become kinked and hence weakened; respiratory movement over time may have caused it to crack and subsequently leak. In the other four patients, the permanent-access catheter was either lost accidentally or removed because of leaking ascitic fluid; none of these patients experienced any clinical consequences. Despite these minor complications, we emphasize that permanent access is established as a precautionary measure for use in case reintervention is needed. It is not a necessity and may be removed safely anytime, accidentally or at will.
More than half of our patients (54%) made use of their permanent-access catheter for biliary reinterventions. The incidence of reobstruction was higher than the 20–41% reported in the literature [6, 11]. This higher incidence of reobstruction was largely because of our policy to examine all patients with suspected stent occlusion and to replace stents with confirmed occlusions. This policy was not implemented by investigators of some reports. For example, Stoker and Lameris [11] reported a reobstruction rate of 20% in 176 patients with metallic stents and a reintervention rate of 14.2%; of those patients, only 76% benefited.
An important consideration with permanent access is the patient's quality of life. One naturally assumes that patients would prefer a completely internalized system without access. At the time of metallic stent insertion, our patients were informed of the pros and cons of an access catheter. They were given the option of removing it if they felt it bothersome. None of our patients took this option. Having experienced tube-related problems, they recognized and valued the benefit of a permanent-access catheter more than the inconvenience of caring for it. The latter was considered to be negligible. For obvious reasons, bed-ridden patients would benefit less from permanent access than those who are active and ambulatory.
We wish to point out the weaknesses of this retrospective study. First, both our patients and the radiologists had reasons to favor the permanent access. Our patients received stents because of repeated catheterrelated problems. They were fearful of losing access in case of reobstruction. The radiologists preferred the permanent-access catheter to avoid performing a new percutaneous biliary procedure in case of stent occlusion. It is not surprising that acceptability among patients was high. Another weakness of our study is its inability to show whether permanent access confers survival benefits. For both issues (acceptability and survival benefit) to be evaluated objectively, a prospective randomized study between two comparable groups of patients with stents—those with and without access catheters—is required.
In summary, we found that permanent access to a metallic biliary stent provided a safe and effective means for reintervention in cases of stent occlusion with acceptable stent patency. Further investigation is required to evaluate its acceptability to patients and whether it confers survival benefits.
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