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Vascular and Interventional Radiology |
1 From the Department of Radiology (K.B.P., Y.S.D., S.W.C., Y.H.H., S.J.L., I.W.C.), Division of Hematology/Oncology, Department of Medicine (W.K.K.), and Department of Medical Engineering (S.W.S.), Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-Dong, Kangnam-Ku, Seoul, 135-710, Korea; and the Department of Radiology, Chung Buk National University Hospital, Cheungju, Korea (K.S.P.). Received June 13, 2000; revision requested July 24; revision received October 12; accepted October 18. Supported by grant HMP-98-G-2-043 of the Highly Advanced National Project, Ministry of Health and Welfare, Republic of Korea. Address correspondence to Y.S.D. (e-mail: ysdo@smc.samsung.co.kr).
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
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MATERIALS AND METHODS: Twenty-four consecutive patients with malignant obstruction of the gastric outlet (n = 22) or duodenum (n = 2) underwent palliative treatment with self-expandable flexible covered metallic stents. Fourteen patients had advanced gastric carcinoma at the antrum and/or pylorus, and eight had obstruction at the anastomosis site of previous gastrojejunostomy. Complications and clinical status were investigated during the study period.
RESULTS: The technical success rate was 75% (18 of 24 patients). Twenty-one stents were placed in 18 patients by using an introducer 6 (n = 7) or 8 mm (n = 14) in diameter. The mean follow-up period was 3.4 months (range, 1 week to 9 months). Symptoms improved in 12 (67%) patients after the procedure. There was no change in symptoms in five and a decrease in one. Twelve patients died during the follow-up period (mean survival, 4.3 months). The complication rate was 25% (six of 24 patients), including stent migration (n = 5) and fracture (n = 3).
CONCLUSION: Flexible covered metallic stent placement can be useful for palliation in patients with malignant obstruction of the gastric outlet or duodenum.
Index terms: Duodenum, stenosis or obstruction, 73.1432 • Gastrointestinal tract, interventional procedures, 72.1269, 73.1269 • Stents and prostheses, 72.1269, 73.1269 • Stomach, neoplasms, 72.30 • Stomach, stenosis or obstruction, 72.1432
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
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The use of self-expandable metallic endoprostheses as a palliative treatment for patients with unresectable gastric cancer causing gastric outlet obstruction has been reported (6–8). A metallic stent allows the patient to eat and improves quality of life. This is an extended study from the work of Park et al (9) to evaluate the usefulness of flexible covered metallic stents especially for the palliation of malignant obstruction of the gastric outlet and duodenum.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
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The causes of gastric outlet obstruction were due to primary advanced gastric carcinoma in 11 patients, postoperative anastomotic stricture due to recurrent gastric carcinoma in eight, pancreatic cancer causing obstruction of the second to third portion of the duodenum in one, gallbladder carcinoma in two, and pyloric obstruction due to metastatic lymph nodes in two with cholangiocarcinoma. In the two patients with gallbladder carcinoma, the obstruction was located in the pyloric antrum and in the pyloric antrum to the second portion of the duodenum, respectively. Sixteen patients had their original anatomic configuration, whereas there was anatomic alteration due to bypass surgery in eight. The gastrojejunostomy was performed with the Billroth I (n = 2) or the Billroth II (n = 6) procedure.
Indications for metallic stent insertion were inoperable primary tumor with distant metastasis in 13, postoperative recurrence of gastric cancer in eight, unresectable pancreatic cancer in one, patient refusal of surgery in one, and poor general condition for surgery in one.
The severity of dysphagia was given one of five scores, according to the patient’s ability to tolerate the diet: 0 = regular diet, 1 = soft diet, 2 = liquid diet, 3 = saliva or water ingestion, and 4 = unable to take anything perorally. Subjective symptoms including nausea and vomiting were also recorded. Informed consent was obtained in all patients before the procedure. The study was approved by the clinical research committee of our hospital (Samsung Medical Center, Seoul, Korea).
Stent Construction
The stent was commercially manufactured (Choostent; Solco Intermed, Seoul, Korea). The basic structure of the flexible covered metallic stent was previously described by Park et al (9). However, there was an alteration in thickness of 3-mm gaps between each metallic stent body part to maintain longitudinal flexibility and to overcome stent fracture. The thickness of polyurethane coverage at the gap portion was 100–200 µm in the previous report (9) and at our early study period, but it was increased to 300–500 µm during our later study period. Five patients received thinner and 13 patients received thicker polyurethane coverage.
The stent was mounted on a polytetrafluoroethylene introducing tube with an outer diameter of 6 or 8 mm. The delivery system was composed of a guiding tip, a guiding tube, an introducing tube, a pusher catheter, and a compressed stent.
Stent Placement
Placement technique was based on that in the previous report by Park et al (9). Stent placement was performed by one of four authors (K.B.P., Y.H.H., S.W.C., Y.S.D.). With fluoroscopic guidance, a 70-cm-long 15-F dilator (Savary-Gilliard; Wilson Cook Medical, Winston-Salem, NC) was introduced through the esophagus, and a 145-cm-long 0.035-inch-diameter hydrophilic guide wire (Radifocus M; Terumo, Tokyo, Japan) was passed into the stomach lumen. Thereafter, the 15-F dilator was exchanged with a 5-F angiographic catheter to help the passage of the guide wire through the pyloric canal and stenotic segment. Successful guide-wire passage was possible with fluoroscopic guidance in 18 patients; however, fluoroscopic guide-wire passage failed in six patients. Endoscopic assistance was attempted in one patient, but the guide wire failed to pass. Immediately after stent placement, serial radiographs were obtained with the oral ingestion of 100–180 mL of barium sulfate (Solotop; Taejoon Pharmaceuticals, Seoul, Korea) to confirm the position and function of the stent.
Technical success was defined as precise placement of the stent in the targeted lesion site, as well as the expansion of the stent to more than 85% of the original stent diameter during the distended phase of peristaltic movement. Reasons for technical failure were recorded.
Patient Follow-up
The patients were allowed a clear liquid diet within 24 hours. When patients tolerated this diet well, the diet progressed to soft or solid food. Status of oral food ingestion was sequentially monitored at 1-month intervals on an outpatient basis with the established five grades of dysphagia. Subjective symptoms were recorded directly from patients by telephone or by reviewing the medical records (K.B.P.).
Barium study was performed 1–3 days after stent insertion for immediate follow-up (Fig 1). This was performed (K.B.P., Y.H.H.) to confirm the position, expansion, and function of the inserted stent. Only if there was decreased oral ingestion was a follow-up barium study indicated. In two patients, a follow-up barium study was performed to evaluate stent function 2 months after stent insertion.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
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Twenty-one stents were placed in 18 patients. In one patient, two stents were placed, one each in the efferent and afferent loops. In another two patients, the second stents were placed because of stent migration. An 18-mm-diameter stent was used in 11 patients, and a 16-mm-diameter stent was used in seven.
Presenting symptoms before stent placement were nausea and vomiting in 13, poor oral intake in two, and postprandial discomfort in three patients. After stent placement, subjective symptoms improved in 12 (67%) patients, did not change in five (28%), and progressed in one (6%). Symptoms improved within 7 days. According to dysphagia scores, only 28% (five of 18) of patients could eat a soft or regular diet before stent insertion; however, the percentage increased to 83% (15 of 18) after stent insertion. Dysphagia scores before and after stent insertion are summarized in the Table. The mean dysphagia scores before and after the procedure were 2.5 and 1.3, respectively. In two patients, the follow-up barium study revealed a well-expanded stent in the expected location without passage disturbance.
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Three patients showed stent fracture. In one patient, stent fracture was detected at the postoperative anastomosis site (afferent loop) 4 months after stent placement (Fig 2). In this patient, the stent placed in the efferent loop showed distal migration. Fractured stent obstructed the gastric outlet, but there was no specific symptom or sign. In the second patient, stent fracture was detected 1 month after stent placement. This patient did not want to receive another stent or other intervention. In the third patient, stent fracture was seen the 3rd day after stent insertion. The patient complained of severe abdominal pain. Therefore, the stent was surgically removed, and the patient underwent feeding jejunostomy. Two stent fractures occurred in stents with thinner polyurethane coverage (two [40%] of five) and one in a stent with thicker coverage (one [8%] of 13). There were no other minor complications.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
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Palliative surgery or intervention can reduce obstructive symptoms and improve quality of life. Surgical palliation has a high morbidity rate, and the result is often not good (11). Laparoscopic gastroenterostomy has been performed, but it is also risky, and it takes a long time to regain gut function postoperatively (12). Nonsurgical interventional procedures have been performed with uncovered stents (13,14). However, an uncovered stent has the limitation of tumor ingrowth through gaps in the stent mesh. In this respect, palliation of gastric outlet obstruction with self-expandable covered flexible metallic stents has great advantages in terms of preventing tumor ingrowth, less invasiveness, immediate improvement of oral intake, less pain during insertion, no need for predilation with a balloon, and easy insertion (9).
Gastric outlet obstruction is located mainly in the antropyloric region, which is usually so acutely angulated that it makes stent placement difficult. Covered Wallstents are now commercially available, but they are too stiff to use in the antropyloric stricture (15). In our study, stent flexibility was increased by making a 3-mm gap between each segment of the stent body.
Peroral insertion of self-expandable metallic stents has some limitations (16). As in our study, redundancy of the greater curvature of the stomach is a big problem, and it prevents the passage of the delivery system and often causes the bending or kinking of the delivery system. An overtube technique or percutaneous route have been used to overcome this problem (17). We also experienced a few cases with insertion failure due to stomach redundancy, which was more common with the 8-mm-diameter introducer system. Therefore, use of the 6-mm-diameter system was of help in reducing the failure rate and in passing the stenotic segment more easily.
The procedure time must be as short as possible, because once the stomach is distended with air, it becomes more difficult to pass the delivery system through the stomach and stenotic segment. A large dilated, empty lumen cannot provide mechanical support to the wire-delivery system. Endoscopic guidance may reduce the procedure time by making guide-wire passage through the stenotic segment easier. Nevertheless, fluoroscopic guidance is enough for successful wire passage in most cases, as occurred in our study.
Yates et al (18) reported improvement of oral intake and obstructive symptoms in 91% of patients with malignant gastric and small intestinal strictures by using self-expanding metallic stents. Although the stents were functioning well, some patients could not eat anything during the late follow-up period owing to severe nausea and loss of appetite. Considering cost-effectiveness, physicians should decide carefully whether to insert stents in patients with advanced terminal malignancy.
The poor technical success rate (75%) was mainly due to device stiffness and lack of endoscopic assistance. Therefore, use of a more slender delivery system and adequate endoscopic guidance can further increase the success rate.
In our study, the complication rate was relatively high compared with that in previous reports in which uncovered metallic stents were used (14,19). Migration was the most common problem (five [24%] of 21 stents) in our study, as well as in other reported cases. In our opinion, stent migration was common in covered stents because the smooth surface of the coverage enabled sliding of the stent. In one patient with distal stent migration, the stent was removed surgically. In the other patients, no further intervention was made.
Uncovered stents have been reported to have a higher rate of tumor ingrowth, which can cause recurrent dysphagia 2–6 months after stent insertion, but migration was rare (15,20). Because a covered stent is less stable than an uncovered one, a new anchoring device would need to be developed to stabilize the stent and prevent migration. Choice of a covered versus an uncovered stent is up to each physician in consideration of the life expectancy of the patient and lesion characteristics.
Stent fracture resulted from stent strut disruption associated with tearing of the polyurethane cover. Most stent fractures occurred at the 3-mm gap in the body of the stent, which consisted of only polyurethane. Since all stent fractures were seen during the early period of our study owing to relatively thin polyurethane coverage, the stent was redesigned to change the thickness of polyurethane coverage from 100–200 µm to 300–500 µm at the gap portion. The fracture rate was greatly decreased thereafter. Thick polyurethane coverage did not influence stent flexibility or insertion procedure.
Self-expandable flexible covered metallic stents may be useful for relief of symptoms and increased food intake in patients with malignant obstruction of the gastric outlet and duodenum.
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FOOTNOTES |
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REFERENCES |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
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This article has been cited by other articles:
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  J. H. Kim, H.-Y. Song, J. H. Shin, E. Choi, T. W. Kim, S. K. Lee, and B. S. Kim Stent Collapse as a Delayed Complication of Placement of a Covered Gastroduodenal Stent Am. J. Roentgenol., June 1, 2007; 188(6): 1495 - 1499. [Abstract] [Full Text] [PDF]
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J. Y. Jeong, J. K. Han, A. Y. Kim, K. H. Lee, J. Y. Lee, J.-W. Kang, T. J. Kim, S. H. Shin, and B. I. Choi Fluoroscopically Guided Placement of a Covered Self-Expandable Metallic Stent for Malignant Antroduodenal Obstructions: Preliminary Results in 18 Patients Am. J. Roentgenol., April 1, 2002; 178(4): 847 - 852. [Abstract] [Full Text] [PDF]
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