Vascular stents and development of endoluminal therapy of aortic aneurysm

Intravascular stents have played an important role in improving early and long-term patency in the treatment of arterial occlusive disease, particularly in the iliac arteries after failed balloon angioplasty. The development of covered stents opened a new dimension for non-operative therapy of aneurysmal disease. Transluminally placed stent-grafts represent a blending of technologies with use of intravascular stents and prosthetic vascular grafts. Stent-graft combinations were first envisioned by Dotter in 1969 as devices that would ultimately be useful to treat aneurysms, pseudoaneurysms and arterio-venous fistulas. Animal studies of endovascular stented grafts demonstrated the potential feasibility of these devices to treat arterial lesions. Parodi et al. first implanted stent-grafts in patients with abdominal aortic aneurysms and demonstrated its clinical feasibility. Newly developed stent-grafts allowed to treat successfully a limited number of patients with AAA. Although much has been reported about the healing properties of prosthetic grafts in extraluminal locations, there are only little data concerning the arterial response to a prosthetic graft placed within the lumen or anchored into the wall of a human vessel. Therefore, long-term evaluation of these new devices will be crucial.     

Effect of growth hormone therapy in children with achondroplasia: growth pattern, hypothalamic-pituitary function, and genotype

PURPOSE: To evaluate the success rates of the implantation of stent grafts in the treatment of peripheral aneurysms. MATERIALS AND METHODS: In 13 patients with 15 aneurysms at the common iliac artery (n = 6), external iliac artery (n = 1), hypogastric artery (n = 2), femoral artery (n = 2) or popliteal artery (n = 4), implantation of dacron-covered nitinol stents was performed. The patients were followed up for three to 20 months (mean, 8.8 months) with intravenous digital subtraction angiography, CT or colour-coded Doppler sonography. RESULTS: In all cases, the aneurysm was successfully occluded after stent implantation. In one case with a popliteal aneurysm, kinking of the vessel caused thrombosis of the stent. The stent was successfully reopened. The aneurysm however, had to be surgically treated 9 months later. The primary and secondary patency rates at 6 months were 93% and 100%, respectively. CONCLUSION: The method described might be an alternative therapy to surgery. There are some limitations in respect of treatment of popliteal aneurysms.     

Differential effect of unfractionated heparin and low molecular weight heparin on intravascular tissue factor pathway inhibitor: evidence for a difference in antithrombotic action

PURPOSE: Successful endovascular repair of an abdominal aortic aneurysm (AAA) requires the creation of a hemostatic seal between the endograft and the underlying aortic wall. A short infrarenal aortic neck may be responsible for incomplete aneurysm exclusion and procedural failure. Sixteen patients who had an endograft positioned completely below the lowest renal artery and 37 patients in whom a porous portion of an endograft attachment system was deliberately placed across the renal arteries were studied to identify if endograft positioning could impact on the occurrence of incomplete aneurysm exclusion. METHODS: Fifty-three patients underwent aortic grafting constructed from a Palmaz balloon expandable stent and an expandable polytetrafluoroethylene (ePTFE) graft implanted in an aorto-ilio-femoral, femoral-femoral configuration. Arteriography, duplex ultrasonography and spiral CT scans were performed in each patient before and after endografting to evaluate for technical success, the presence of endoleaks, and renal artery perfusion. RESULTS: There was no statistically significant difference in patient demography, AAA size, or aortic neck length or diameter between patients who had their endografts placed below or across the renal arteries. However, significantly more proximal aortic endoleaks occurred in those patients with infrarenal endografts (P < or = .05). Median serum creatinine level before and after endografting was not significantly different between the 2 patient subgroups, with the exception of 2 patients who had inadvertent coverage of a single renal orifice by the endograft. Median blood pressure and the requirement for antihypertensive therapy remained the same after transrenal aortic stent grafting. Significant renal artery compromise did not occur after appropriately positioned transrenal stents as shown by means of angiography, CT scanning, and duplex ultrasound scan. Mean follow-up time was 10.3 months (range, 3 to 18 months). Patients who had significant renal artery stenosis (> or =50%) before aortic endografting did not show progression of renal artery stenosis after trans-renal endografting. Two patients with transrenal aortic stent grafts had inadvertent coverage of 1 renal artery by the endograft because of device malpositioning, which resulted in nondialysis dependent renal insufficiency. In addition, evidence of segmental renal artery infarction (<20% of the kidney), which did not result in an apparent change in renal function, was shown by means of follow-up CT scans in 2 patients with transrenal endografts. CONCLUSION: Transrenal aortic endograft fixation using a balloon expandable device in patients with AAAs can result in a significant reduction in the risk of proximal endoleaks. Absolute attention to precise device positioning, coupled with the use of detailed imaging techniques, should reduce the risk of inadvertent renal artery occlusion from malpositioning. Long-term follow-up is essential to determine if there will be late sequelae of transrenal fixation of endografts, which could adversely effect renal perfusion.     

Genetic therapies for xenotransplantation

PURPOSE: To determine the optimal postoperative imaging modality for the follow-up of patients with endoluminal aortic stent grafts. MATERIAL AND METHODS: From August 1994 to November 1997, 214 patients (194 male and 20 female) with abdominal and thoracic aortic aneurysms were treated with endovascular stent grafts. 137 patients (129 male, 8 female) with 89 tube grafts and 48 bifurcated grafts (45 EVT, 88 Stentor/Vanguard, 3 Chuter, 1 Talent) were evaluated with contrast-enhanced spiral-CT, duplex ultrasound, and DSA at a mean follow-up of 11.1 months. RESULTS: We found 12 persistent primary endoleaks (8.8%), 17 secondary endoleaks (12.4%), 8 limb occlusions (5.8%), 28 endoluminal thrombi lining the stent graft (20.4%), and 26 suture breakages of the stent frame (19%). In 9 patients (6.6%) the proximal end of the stent partially covered the renal arteries. In 3 patients (2.2%) a partial renal infarction was seen. Spiral-CT was able to demonstrate all the above changes except for 3 sidebranch endoleaks that were documented by duplex ultrasound only and 8 suture breaks seen on abdominal plain films only. The median aneurysm diameter decreased from 48 mm pre-operatively to 46 mm at 24 months post-operatively in patients with endoleaks and from 44 mm to 36 mm in patients without endoleak. For several patients the decreasing aneurysm diameter did not reliably correlate with complete exclusion of the aneurysm. CONCLUSION: For follow-up of endoluminal aortic stent grafts contrast-enhanced spiral-CT is superior to duplex ultrasound. DSA is necessary only for patients with complications requiring a secondary intervention.     

Using polymerase chain reaction for rapid sex-determination of a case of sirenomelia

Developing endoluminal technology has permitted the management of selected aneurysms using stent-grafts, but the applicability and durability of these new devices has not yet been proven. Standard treatment of mycotic aneurysms generally requires arterial ligation, excision and debridement, and autologous or extraanatomic synthetic bypass. A saphenous vein-covered stent was used to exclude an expanding, mycotic, superficial femoral artery aneurysm in a critically ill patient. Although stent-graft exclusion was intended as a bridge to standard therapy, the mass resolved, the superficial femoral artery remains patent, and the patient is symptom-free at 1 year without further intervention. Additional experience is required to determine whether stent-grafts have a role in the management of mycotic aneurysms.     

Postoperative color flow duplex scanning in aortic endografting

PURPOSE: To report the feasibility and sensitivity of duplex sonography compared to computed tomography (CT) for aortic endograft follow-up surveillance. METHODS: In a 26-month period, 113 aortic aneurysm patients received 79 tube and 34 bifurcated stent-grafts. Follow-up used contrast-enhanced CT scanning and duplex sonography with an intravenous ultrasound contrast agent (Levovist). RESULTS: Eleven patients (9.7%) were converted to open repair; 1 died from hemorrhagic shock secondary to retroperitoneal hematoma. The mean follow-up time was 7.2 months (range 1 to 24), during which 5 patients died of unrelated causes. Sixteen primary (within 30 days) and 5 secondary endoleaks were detected by duplex after tube graft implantation. Among 5 endoleaks due to retrograde side-branch perfusion, 3 were detected only with contrast-enhanced duplex scanning. Iliac artery occlusion was also documented using duplex; however, 2 stent fractures could not be seen with ultrasound. Ten primary endoleaks were detected in bifurcated stent-graft patients. One endoleak originating from the distal iliac limb anchoring site was missed by duplex owing to bowel gas. Graft limb thrombosis was clearly identified by lack of a flow signal on duplex. CONCLUSIONS: Duplex sonography could be a valuable, reliable, and economical surveillance tool for endovascular aortic reconstructions. The adjunctive use of an intravenous ultrasound contrast agent increased the sensitivity for detecting endoleak to a level comparable to contrast-enhanced CT scanning. However, stent fractures may not be seen on ultrasound, and bowel gas can interfere with obtaining an adequate image.     

Intravascular stent and endovascular coil placement for a ruptured fusiform aneurysm of the basilar artery. Case report and review of the literature

The authors demonstrate the technical feasibility of using intravascular stents in conjunction with electrolytically detachable coils (Guglielmi detachable coils [GDCs]) for treatment of fusiform, broad-based, acutely ruptured intracranial aneurysms and review the literature on endovascular approaches to ruptured aneurysms and cerebral stent placement. A 77-year-old man presented with an acute subarachnoid hemorrhage of the posterior fossa. A fusiform aneurysm with a broad-based neck measuring 12 mm and involving the distal vertebral artery (VA) and proximal third of the basilar artery (BA) was demonstrated on cerebral angiography. The aneurysm was judged to be inoperable. Six days later a repeated hemorrhage occurred. A 15-mm-long intravascular stent was placed across the base of the aneurysm in the BA and expanded to 4 mm to act as a bridging scaffold to create a neck. A microcatheter was then guided through the interstices of the stent into the body and dome of the aneurysm, and GDCs were deposited for occlusion. The arteriogram obtained after stent placement demonstrated occlusion of the main dome and body of the aneurysm. The coils were stably positioned and held in place by the stent across the distal VA and BA fusiform aneurysm. Excellent blood flow to the distal BA and posterior cerebral artery was maintained through the stent. There were no new brainstem ischemic events attributable to the procedure. No rebleeding from the aneurysm had occurred by the 10.5-month follow-up evaluation, and the patient has experienced significant neurological improvement. Certain types of intracranial fusiform aneurysms may now be treated by combining intravascular stent and GDC placement for aneurysm occlusion via an endovascular approach. This is the first known clinical application of this novel approach in a ruptured cerebral aneurysm.     

Transfemoral endovascular aortic graft placement

PURPOSE: The purpose of this study was to develop an endovascular system for transfemoral placement of straight aortic grafts and bifurcated aortoiliac grafts. METHODS: Both types of graft consist of barbed, self-expanding stents attached to a woven polyester fabric. Survival studies of straight-graft function were performed in six large mongrel dogs. Digital subtraction fluoroscopic equipment was used to guide insertion and record angiograms at 0, 1, and 3 months. Bifurcated grafts were inserted in an additional eight dogs, four with distal stents and four without. Straight grafts were inserted into six cadaveric aortas (five atherosclerotic and one aneurysmal; age 68.7 + 5.7 years) to assess stent attachment. RESULTS: Angiograms obtained immediately after straight-graft insertion showed placement to be within 4.6 + 1.6 mm of the intended level. Follow-up angiograms at 1 and 3 months showed no migration, no leakage, and patency of all six grafts. After bifurcated graft insertion there were no angiographic signs of perigraft leakage, with or without distal stents. The mean force required to displace straight grafts 10 mm from their original position in cadaveric aortas was 1388 + 127 g. CONCLUSION: These preliminary results show that straight and bifurcated endovascular grafts can be positioned accurately and securely in the abdominal aorta.     

Endovascular stent graft repair for aneurysms on the descending thoracic aorta

BACKGROUND: The traditional treatment of aneurysms of the descending thoracic aorta includes posterolateral thoracotomy and aortic replacement with a prosthetic graft. In this study, we report our experiences and results in endovascular stent graft placement as an alternative to surgical repair. METHODS: Between January 1989 and July 1997, a total of 68 patients (24 women) underwent replacement of the thoracic aorta. Mean age at operation was 51 years. Fifty-eight patients underwent conventional surgical treatment. All of these patients were suitable candidates for endovascular stenting; however, no stent graft material was available at the time of operation. Ten patients (1 chronic dissection, 9 atherosclerotic aneurysm) received in the past 8 months the first commercially manufactured endovascular stent graft. The mean diameter of the aneurysms in this group was 7 cm (range, 6 to 8 cm). Two stent patients were operated on using only spinal cord analgesia. All stent grafts were custom designed for each of the 10 patients. RESULTS: The 30-day mortality in the conventional group was 31% versus 10% in the stent group. Mean length of intervention was 320 minutes in the conventional group versus 150 minutes in the endovascular group. Spinal cord injury occurred in 5 patients (12%) in the surgical group, whereas none of the stented patients developed any neurologic sequelae. Mean intensive care unit stay was 13 days, followed by a mean of 10 days on a ward in the first group compared to 4 days in the intensive care unit and 6 days on the ward in the stent group. One stent was required in 2 patients, two stents were required in 3 patients, and four stents were deployed in 5 patients of our series. Five patients required transposition of the left subclavian artery to achieve a sufficient neck for the proximal placement of the stent. There was complete thrombosis of the thoracic aortic aneurysm surrounding the stent graft in 8 patients (80%). Two patients required restenting as a result of leakage (20%). Stent graft placing was performed through the femoral artery in 8 patients, whereas access was only achieved through the abdominal aorta in 2 patients. CONCLUSIONS: These preliminary results demonstrate that endovascular stent graft replacement might be a promising, cheaper, and safe alternative method in selected patients with descending thoracic aneurysms.     

Endovascular stent graft placement for patients with aortic aneurysm and end-organ dysfunction

Endovascular stent grafts (ESGs) for the treatment of aortic aneurysm is becoming popular because it is less invasiveness for the patient. This new modality seems to be especially useful for treating high risk patients, such as those with end-organ dysfunction. In this study we retrospectively analyzed the results of ESG placement for patients with renal or hepatic dysfunction. From January 1996 to December 1997, six patients with end-organ dysfunction (two with descending thoracic aneurysm and four with abdominal aneurysm) underwent ESG placement. Five of these patients had renal dysfunction, with serum creatinine levels of 2.0 mg/dl or greater, and the remaining patient had hepatic dysfunction with a prothrombin time less than 60%. One of the patients also had severe atherosclerotic disease with a history of multiple brain infarctions. All the patients received custom made endovascular spiral Z stents covered with a woven Dacron (DuPont Co., Wilmington, DE) graft, which was delivered via a femoral artery under local anesthesia. None of the patients showed significant changes in renal or hepatic function after the procedure. None of the five patients with renal dysfunction needed hemodialysis after ESG placement, although the mean preoperative level of serum creatinine and blood urea nitrogen was 3.4 mg/dl and 42.0 mg/ dl, respectively. All the patients left the recovery room on postoperative day 1. These results indicated that endovascular stent graft placement is extremely useful in the treatment of aortic aneurysm patients with end-organ dysfunction.     

Stents in aortic coarctation. Immediate results

From September 1996 to March 1997 we implanted stents Palmaz (P-308 Johnson & Johnson) in six patients with aortic coarctation. Age ranged from 13 to 30 years (mean = 20), 3 female and 3 male. We implanted the stent without predilation. Balloon diameter was 12 mm in two cases and 15 mm in four cases for complete expansion we used 14 to 20 mm balloon diameter in five instances and in one case we used a dual balloon 15 + 15 mm. The gradient pre-stent ranged from 30 to 65 mmHg (mean = 44) and decreased to 0 mmHg in five cases and in one patient the residual gradient was 4 mmHg. Systolic aortic pressure pre-stent was 135 mmHg and decreased to 117 mmHg. There were no significant complications. In conclusion, we have demonstrated the feasibility of balloon-expandable stent implantation as a method of alleviation the obstruction in coarctation of the aorta in this group of patients. It is an excellent alternative to surgical treatment and it is better than balloon angioplasty that results in marked improvement in the angiographic appearance of the thoracic aorta. It eliminates the gradient, has minimum morbidity and no mortality, no aneurysm formation. Late restenosis and possible aneurysm formation remains an unlikely complication in view of the ample luminal diameter and the high velocity of flow.     

Analysis of T-cell receptor gene rearrangement in lymph nodes of patients with mycosis fungoides. Prognostic implications

PURPOSE: To evaluate different vein grafts for luminal coating of endovascular stents in normal canine arteries. METHODS: Twenty-four tantalum Strecker stents were coated with either autologous (n = 10), denatured heterologous (n = 11), or denatured homologous vein grafts (n = 3). The carotid artery (n = 11) and the iliac artery (n = 13) were stented using a transfemoral approach. Angiograms were performed at days 0, 7, and 21, and months 3, 6, and 9. All grafts underwent histological examination. RESULTS: Eight of 10 autologous vein grafts showed patency during the whole observation period of 9 months, without histological signs of inflammation. Denatured heterologous vein grafts revealed acute (n = 3), subacute (n = 5), or delayed (n = 3) vessel occlusion. Hyaloid transformation of the vein graft and lympho-plasmacellular formations were seen. Denatured homologous vein grafts showed acute vessel occlusion. Although significant inflammatory tissue response was seen, no host-versus-graft reaction was present. CONCLUSION: Autologous vein graft-coated stents showed good biocompatibility in canine arteries. Preparation was cumbersome and required surgical venae-sectio. Denatured vein grafts, however, were limited by inflammatory reactions.     

Abdominal aortic aneurysms in sheep: prevention of rupture with endoluminal stent-grafts

PURPOSE: The authors evaluated the ability of an aortic balloon-expandable endovascular stent-graft to prevent rupture in a model of spontaneously rupturing abdominal aortic aneurysms in sheep. MATERIALS AND METHODS: Aneurysms were created in 16 sheep by inserting a 60 x 18-mm segment of the left internal jugular vein, end-to-end anastomosed, to the sectioned infrarenal abdominal aorta. The sheep were randomly assigned into two groups; eight animals underwent endovascular implantation of an 80 x 12-mm balloon expandable stent-graft (group A), and eight were only followed up (group B). RESULTS: In group B, seven of eight animals had died of aneurysmal rupture by 3 months. In group A, six of the eight aortic aneurysms were immediately excluded, and six animals were alive at 3 months without rupture. The 3-month survival rate was 100% in group A and 12% in group B (P = .0023). Macro- and microscopic analysis of the section of the aorta in which the stent-graft had been placed revealed rapid retraction of the aneurysmal sac. CONCLUSION: Placement of an endovascular stent-graft induced regression of a branchless aneurysm and prevented rupture.     

A prospective randomized trial of Teflon versus polyethylene stents for distal malignant biliary obstruction

BACKGROUND AND STUDY AIMS: Clogging of biliary stents continues to be a major clinical problem. Different polymer materials may have different effects on clogging. In vitro studies have shown a direct relation between the frictional coefficient of a polymer and the amount of encrusted material. Teflon appeared to be the best polymer for biliary stents. Two different types of stents made of Teflon have been tested in clinical practice and showed favourable patency rates. However, a randomized trial has never been performed. We compared the patency of an Amsterdam-type polyethylene stent with a Teflon stent in a prospective randomized trial. PATIENTS AND METHODS: Between September 1995 and November 1996, 42 patients received a Teflon stent and 42 patients a polyethylene stent. All patients had a distal malignant biliary stricture without a previous drainage procedure. Diagnoses included carcinoma of the pancreas (n = 76), papilla (n = 1), bile duct (n = 5) and metastases (n = 2). The internal and external diameter (10 Fr), length (9 cm) and stent design (a straight stent with two side flaps and one side hole at each end) were similar for both stents. RESULTS: A reduction in bilirubin of more than 20% within one week was seen in 91% of the patients. Early complication rates were similar in both groups (10%). The median follow-up was 142 days. Stent dysfunction occurred in 28 Teflon and 29 polyethylene stents. The thirty-day mortality was 14% in both groups. Patient survival did not differ significantly between the groups (median survival: Teflon 165 days, polyethylene 140 days). The median stent patency was 83 days for Teflon and 80 days for polyethylene stents, and was not significantly different either. CONCLUSION: Teflon material did not improve patency in biliary stents with an Amsterdam-type design.     

Treatment of malignant esophageal obstructions with covered metallic Z stents: long-term results in 52 patients

PURPOSE: To prospectively evaluate the clinical efficacy of silicone-covered Gianturco-R?sch self-expandable Z (GRZ) stents in the treatment of malignant esophageal obstruction. PATIENTS AND METHODS: GRZ stents were placed in 52 patients (39 men, 13 women) with severe dysphagia due to high-grade malignant esophageal obstruction. RESULTS: Stent placement was technically successful, and immediate relief of dysphagia was achieved in 50 of 52 patients (96%), with long-term relief in 47 patients (90%). Fifty-one patients (98%) died during follow-up (range, 1 week to 33 months; mean, 4.3 months). Late complications were most prevalent and included stent migration (n = 5), food impaction (n = 2), chest pain (n = 2), membrane disruption with tumor ingrowth (n = 1), granulomatous reaction above the stent (n = 1), esophageal perforation with mediastinitis (n = 1), and upper gastrointestinal hemorrhage (n = 4). Twelve complications were easily managed with medical, endoscopic, or radiologic intervention. Four deaths may have been related to stent placement (early mortality rate, 7.7%). CONCLUSION: GRZ stents provide relatively safe and effective long-term palliation in patients with severe, malignant esophageal obstruction.     

Percutaneous coronary angioplasty of radial artery conduits

The higher long-term patency of internal mammary artery grafts has stimulated the search for alternative conduits in order to achieve a complete arterial myocardial revascularization. Percutaneous angioplasty is often the preferred strategy for the treatment of recurrent ischemia in patients who previously underwent bypass surgery, but there is limited experience in the treatment of arterial grafts. We describe two cases of percutaneous treatment of diseased radial artery (RA) grafts. In the first case, two disarticulated stents were deployed through an RA graft: half stent inside the anastomosis to the left anterior descending (LAD) artery, and half stent in the distal LAD artery. Diffuse spasm of the RA graft, resistant to ic nitrates, was successfully reversed after ic calcium antagonists. Absence of restenosis was confirmed two years later. In the second case, after simultaneous catheterization of both the left coronary artery and RA graft, two long stents were implanted in the LAD artery and a final "reversed" kissing-balloon dilation through the stent struts was performed; four months later the patient showed proximal occlusion of the LAD artery and the stenotic RA distal anastomosis was successfully dilated.     

Metallic stents in malignant biliary obstruction: prospective long-term clinical results

OBJECTIVE: The purpose of this prospective study was to evaluate the long-term clinical efficacy of metallic stents when used as the initial palliative treatment of patients with inoperable malignant biliary obstruction. SUBJECTS AND METHODS: From August 1991 through May 1995, 100 consecutive patients with malignant biliary obstruction were treated with percutaneous placement of metallic stents. The causes of obstruction were bile duct carcinoma (n = 50), pancreatic carcinoma (n = 17), gallbladder carcinoma (n = 6), hepatocellular carcinoma (n = 2), and metastatic lymphadenopathy in the hepatoduodenal ligament (n = 25). We used 123 stents: 64 Gianturco Z stents, 39 Hanaro spiral stents, 16 Wallstents, two tantalum Strecker stents, one Endocoil stent, and one Memotherm nitinol stent. Every 3 months we followed up all patients except those who died. The average length of follow-up was 220 days (range, 4-1125 days). Patient survival and stent patency rates were estimated by life-table analysis. RESULTS: The median length of survival for the entire patient group was 246 days: 25-week and 50-week survival rates were 62% and 25%, respectively. We found no statistically significant difference in the median length of survival between patients with hilar obstruction (256 days) and patients with common bile duct (CBD) obstruction (227 days). Patients with bile duct carcinoma had longer median survival (269 days) than did patients with other conditions (197 days). The overall median length of patency for all stents was 360 days; the 25-week and 50-week patency rates were 81% and 53%, respectively. The stent patency rate at the median length of survival was 71%. The median length of stent patency in patients with hilar obstruction (617 days) was nearly double that of patients with CBD obstruction (324 days). However, the median length of stent patency in patients with bile duct carcinoma showed no statistically significant difference from the median length in patients with other disease. Four patients (4%) died within 1 month after stent placement. Twenty-one patients (21%) developed recurrent jaundice or cholangitis. In order of frequency, the causes of recurrent jaundice were tumor overgrowth, incrustation of bile sludge, duodenal obstruction due to tumor invasion, stent impaction into the bile duct wall, stent malposition, and tumor ingrowth. CONCLUSION: Metallic stents showed a favorable patency rate with regard to patient survival. In patients with hilar obstruction, the clinical efficacy of metallic stents was superior to that in patients with CBD obstruction. We believe that placement of metallic stents is the procedure of choice for palliation of malignant biliary obstruction.     

Application of rectal stents for palliation of obstructing rectosigmoid cancer

BACKGROUND: The rationale of palliative endoscopic treatment is to avoid a colostomy in patients with advanced disease and limited life expectancy. This study was conducted to evaluate the role of endoscopic stent implantation for palliation of obstructing rectal cancer. METHODS: Overall, 19 patients (aged 47-87 years) with nonresectable or metastatic rectal cancer were treated by stent insertion after laser recanalization or dilation. Three types of stents, i.e., plastic tubes (n = 8), self-expanding mesh stents (n = 6), and endocoil stents (n = 5), were used to maintain luminal patency. RESULTS: Endoscopic stent implantation was successfully performed in all 19 patients. Long-term luminal patency and satisfactory bowel function were achieved in 16 of 19 patients (84%). After a median follow-up of 6 months, eight of the patients have died and eight are still alive without evidence of recurrent obstruction. Dislocation of the endoprosthesis occurred in two of eight plastic tubes and one of five mesh stents. Recurrent obstruction due to tumor ingrowth was only observed in patients treated with self-expanding mesh stents (n = 2). In spite of reinsertion and laser therapy a colostomy was required in three of 19 patients. There was no evidence of treatment failure in five patients who received endocoil stents. None of the patients experienced serious complications related to the endoscopic procedure. CONCLUSIONS: Endoscopic stent implantation seems to be a safe and efficient palliative approach to selected patients with obstructing rectal cancer. Currently, self-expanding coil stents are superior to other devices because of lower risk of dislocation and tumor ingrowth.     

Clinical results of endovascular stent graft repair for fifty cases of thoracic aortic aneurysms

Between February 1995 and December 1997, 50 cases (55 lesions) of thoracic aortic aneurysms including 20 cases of aortic dissections were treated with an endovascular technique using the stent grafts. All patients were treated in the operating room under general anesthesia and the stent grafts were implanted through 18 Fr. or 20 Fr. sheaths via femoral arteries under fluoroscopic guidance. The stent graft was composed of several units of self-expanding stainless-steel Z stents covered with an ultra-thin polyester fabric. Stent graft deployment was technically successful in 53 of 55 lesions (delivery success rate: 96.4%). Exclusion of the aneurysms and entry closing without endoleak were achieved within two weeks after the operation in 43 of 53 lesions (initial success rate: 81.1%). Endoleak was found in 10 lesions (minor endoleak: 8 and major endoleak: 2 lesions). Two patients died in the periopertive period of delivery failures as injury to external iliac artery and damage to the delivery sheath caused by tortuous and narrow access routes. Endovascular stent graft repair of thoracic aortic aneurysms is minimally invasive operation in comparison with conventional surgical graft replacement with extracorporeal circulation. These early results suggest that the stent graft repair is possibly safe and useful treatment for the patients of thoracic aortic aneurysms especially in high risk patients. However, careful long-term follow-up is necessary to prove the value and the effects of this endovascular treatment and improvement of the stent graft system and technical training of endovascular surgery for operators are required to reduce the delivery failure and to determine the stent graft repair is reliable treatment.