Peripherally inserted central catheters with distal versus proximal valves: prospective randomized trial.

PURPOSE: To evaluate whether peripherally inserted central catheters (PICCs) with a proximal valve have any advantage compared to those with a distal valve in regard to the incidence of occlusion, infection, or malfunction. MATERIALS AND METHODS: One hundred patients (mean age, 46 y) were randomized to receive either a distal-valved Bard Groshong catheter (n = 48) or a proximal-valved Catheter Innovations Pressure Activated Safety Valve catheter (n = 52). All catheters were 4-F, single-lumen PICCs. Catheters were placed under fluoroscopic (n = 82) or sonographic (n = 18) guidance. Most (91%) were placed for the administration of antibiotics. The placement procedure, maintenance, and weekly follow-up were the same for both catheters. RESULTS: Percutaneous placement with the catheter tip in the central veins was successful in all patients. Mean dwell time was 36 days. There were 12 (25%) occlusive or infectious complications in the distal valve catheter group and six (11.5%) in the proximal valve group (P = .08). There were 25 fractures in 17 distal valve catheters (35.4%) and three (5.8%) proximal valve catheter fractures (P < .01). CONCLUSION: There was a marked difference in durability between the valved catheters, in favor of the catheter with a proximal valve. There was also a trend for fewer occlusive and infectious complications with the proximal valve catheter.

Type III heart block with peripheral use of the Angiojet thrombectomy system.

The authors describe the occurrence of type III heart block in a patient undergoing a transjugular intrahepatic portosystemic shunt recanalization with use of the AngioJet thrombectomy system.

Stent placement in the treatment of pulmonary artery stenosis secondary to fibrosing mediastinitis.

This article describes an initial experience with stent placement in three patients with severe pulmonary artery stenosis secondary to fibrosing mediastinitis. All three patients were severely symptomatic on admission and all three were asymptomatic after treatment and remained symptom-free approximately 1 year after treatment.

Evaluation of local abciximab delivery from the surface of a polymer-coated covered stent: in vivo canine studies.

PURPOSE: To determine the in vitro feasibility of abciximab absorption and elution from a polymer-coated, silicone-covered stent, and to determine the in vivo effect of local delivery of abciximab concerning endothelialization of a polymer-coated, silicone-covered stent in a canine model. MATERIALS AND METHODS: Six polymer-coated, silicone-lined Wallstents were soaked in 2 mg/mL of concentrated solution of I131-labeled abciximab for a period as long as 48 hours. Quantification of abciximab absorption was determined by photon emission. Six maximally drug-loaded devices were then washed continuously with normal saline with use of a pustule pump apparatus. The quantity of residual abciximab was determined by photon emission for a period as long as 16 days. Eight similar devices (as described previously) were then implanted within the iliac arteries of four adult canines. Devices were identical except that four of eight were maximally loaded with abciximab. For each animal, one control implant was placed in the right iliac artery and one experimental implant (drug loaded) was placed in the left iliac artery, via right carotid cutdown. Animals were allowed to recover and no chronic medications were given. After an interval of 6 weeks, the animals were killed. Implants were isolated and perfused with 10% buffered formalin at a pressure of approximately 100 mm Hg for a period of 1 hour. Each implant was encased in methacrylate, sectioned into six equal segments, ground and polished, and stained with hematoxylin and eosin. Each slide was projected on a screen and the thickness of the neointima quantified. The mean neointima was determined for control and experimental groups, and compared for a potential significant difference with a Student t test. RESULTS: Mean absorption of abciximab was 21.53 microg +/- 2.99 per device. Devices were fully saturated at 24 hours. Forty percent was absorbed at 1 hour, and 60% and 80% were absorbed at 4 hours and 12 hours, respectively. Regarding elution, 30% of abciximab was washed out after 1 hour. There was a gradual elution of the drug to 16 days, with approximately 40% remaining at the end of the term. Mean neointimal thickness was 995 microm +/- 597 for the experimental group and 1,738 microm +/- 1,042 for the control group. The difference was significant (P <.05). CONCLUSIONS: Absorption and elution of abciximab from the surface of a covered stent is feasible. Local delivery of abciximab from the surface of this covered stent reduced the thickness of endothelial lining in the canine iliac artery compared to control.

Seat belt aorta: endovascular management with a stent-graft.

PURPOSE: To report the endovascular treatment of a relatively uncommon type of deceleration injury to the abdominal aorta. CASE REPORT: A 21-year-old backseat passenger was wearing a single lap belt without shoulder harness when the car was involved in a collision. He sustained a transverse (Chance) fracture of the third lumbar vertebra and a circumferential dissection of the infrarenal abdominal aorta with pseudoaneurysm. As an interim measure while a stent-graft was obtained, a Wallstent was deployed to tack down the dissection and prevent distal embolization. Thirty-six hours later, an AneuRx endograft was successfully implanted inside the Wallstent to seal the pseudoaneurysm. The patient's recovery was uneventful, and the endograft remains secure and the pseudoaneurysm excluded at 10 months after the accident. CONCLUSIONS: Endovascular repair of "seat belt aorta" is a minimally invasive, straightforward method of management for this type of aortic injury. The potential for infection in a contaminated peritoneal cavity and the long-term outcome of this treatment have not been determined.

Evaluation of silicone as an endovascular stent membrane: in vivo canine studies.

PURPOSE: Comparative evaluation of the biological effects of a silicone-covered stent versus a bare-metal stent, in an animal model. METHODS: Twelve stent implants were placed in the iliac arteries of six adult dogs. Each animal received one 8-mm x 20-mm silicone-covered stent (Permalume; Boston Scientific Vascular, Watertown, MA, USA), in the right iliac artery and one Wallstent (Boston Scientific Vascular) of the same diameter and length in the left iliac artery, during systemic anticoagulation. Angiography was performed before and after implantations. Animals were then allowed to recover and no platelet suppression was given during a 6-week interval, after which the animals were euthanized. The stented arteries were isolated and pressure-fixed in situ with 10% buffered formalin at a pressure of approximately 100 mmHg for a period of 1 hr. Two of 12 stented specimens were opened lengthwise and the luminal surfaces were photographed. Ten of 12 stented arterial segments were encased in methacrylate, then stained with hematoxylin and eosin. Neointimal thickness was quantified on histologic cross-section, for both bare and covered stents. The mean neointimal thicknesses were compared for significant difference using a student t-test. RESULTS: All implants were widely patent at 6-week follow-up angiography. Histologic analysis showed bare metal stents covered by a thin uniform lining of neointima composed of smooth muscle cells in a hyaline matrix (mean thickness of 189 +/- 47 microm). Silicone covered stents were devoid of neointima. There was no chronic thrombus or mature endothelium noted anywhere upon the internal silicone surfaces of any of the specimens. There was no foreign body reaction to the silicone cover. CONCLUSION: Short-term implantation of a silicone-lined Wallstent in canine iliac arteries is well tolerated. Silicone appears to be inert at 6 weeks in this experimental application.

Retrospective comparison of the patency of Wallstents and Palmaz long-medium stents used for TIPS. Transjugular intrahepatic portosystemic shunts.

PURPOSE: To compare patency rates of transjugular intrahepatic portosystemic shunts (TIPS) after placement of long-medium Palmaz stents or Wallstents. METHODS: We performed a retrospective review of TIPS performed at our institution between December 1997 and December 1998. During this time period we placed long-medium Palmaz stents for TIPS procedures in 17 patients and Wallstents in 20 patients as the initial stent. Patency was determined on follow-up by ultrasound, angiography, or pathologic examination in the event of transplant. RESULTS: Primary patency in the Palmaz stent group was 70.6% (12/17 patients) (follow-up 1-399 days, mean 127 days). Both primary assisted and secondary patency in the Palmaz group was 100% (17/17 patients) (follow up 1-399 days, mean 154 days). Primary patency in the Wallstent group was 50% (10/20 patients) (follow up 1-370 days, mean 65 days). Primary assisted patency in the Wallstent group was 80% (16/20 patients) (follow up 1-601 days, mean 141 days). Secondary patency in the Wallstent group was 100% (20/20 patients) (follow up 2-601 days, mean 142 days). Kaplan-Meier analysis of the two groups of patients yielded a primary patency of 266 days (standard error 45 days) for TIPS with the Palmaz stent and 139 days (standard error 45 days) for the Wallstent (p =.04). The 3, 6, and 12-month primary patency rates were .84, .63, and .42 respectively for the Palmaz stents and .36, .36, and .18 respectively for the Wallstent. There was no significant difference in primary assisted or secondary patency between the two stent groups. The mean tract curvature in the patients with Palmaz stents was 23.5 degrees (SD 18.2 degrees, range 0-69.0 degrees ) compared with 57 degrees (SD 34.5 degrees, range 7.0-144.0 degrees ) in patients with Wallstents (p =.01). CONCLUSIONS: Our nonprospective, nonrandomized study suggests that TIPS created with the long-medium Palmaz stent have a higher primary patency than those created with the Wallstent in tracts that are relatively straight.

Primary placement of Palmaz long medium stents in transjugular intrahepatic portosystemic shunts.

PURPOSE: To describe our results with primary placement of the long-medium Palmaz stent for transjugular intrahepatic portosystemic shunts (TIPS). MATERIALS AND METHODS: Between December 1997 and December 1998 primary placement of long-medium Palmaz stents was performed for TIPS procedures in 17 patients. Patency was determined with ultrasound, angiography, or pathologic examination in the event of transplant. RESULTS: Primary patency was achieved in 13 of 17 patients (76.5%) (follow up, 1-399 days; mean, 99 days). Secondary patency was achieved in 17 of 17 patients (100%) (follow-up, 1-399 days; mean, 110 days). Among the four patients who required revision, the mean time to revision from initial shunt creation was 81 days (range, 13-125 days). Two of these four patients had symptoms of worsening ascites as well as abnormal ultrasound findings prior to their revision; the other two patients were asymptomatic and had abnormal ultrasound findings only. Revisions were performed for intimal hyperplasia within the stent in three of the patients and acute thrombus within the stent in the remaining patient. Kaplan-Meier survival analysis for primary patency yielded mean survival time of 265 days (standard error, 52 days). CONCLUSION: The long-medium Palmaz stent is a viable stent for creation of TIPS shunts.

Prospective randomized comparison of valved versus nonvalved peripherally inserted central vein catheters.

OBJECTIVE: The purpose of this study was to evaluate whether a valved peripherally inserted central catheter (PICC) design would result in a lower incidence of occlusion, infection, and malfunction than a clamped catheter. SUBJECTS AND METHODS: Three hundred sixty-two study patients (233 men, 129 women; mean age, 44 years) were randomized to receive a clamped (n = 182) or valved (n = 180) 5-French single-lumen PICC. Catheters were placed under fluoroscopic (n = 331) or sonographic guidance (n = 31). The valved PICC was flushed with saline solution, and the clamped PICC was flushed with a heparin-saline solution. All patients were prospectively followed up at least weekly for catheter status and complications. RESULTS: Percutaneous placement with the catheter tip in the central veins was successful in 99% of patients. Mean dwell time was 34 days. Twenty-six occlusive or infectious complications occurred in the clamped catheter group and 12 in the valved catheter group (p = .02). The clamped and valved catheter groups had 13 and five occlusions, respectively (p = .06), and 12 and five catheter-related blood stream infections, respectively (p = .09). Most occlusions (68%) were treated successfully with urokinase, and site infection or sepsis was treated by catheter removal. CONCLUSION: We found a statistically significant difference in the complication rate for the valved PICC compared with the clamped PICC. With the valved PICC, occlusion and infection were reduced, and patients having these catheters did not require heparin flushes.

Transcatheter arterial embolization for intractable epistaxis secondary to gunshot wounds.

PURPOSE: To evaluate the efficacy of transcatheter arterial embolization for intractable epistaxis secondary to gunshot wounds. MATERIALS AND METHODS: Seven patients with intractable epistaxis secondary to penetrating trauma (gunshot wounds) were studied with angiography and subsequently underwent embolization with particles (polyvinyl alcohol, gelatin sponge) and/or microcoils. Clinical follow-up included standard hemodynamic monitoring, serial hematocrit determinations, and clinical observation for recurrent bleeding. RESULTS: Diagnostic angiography demonstrated evidence of acute arterial injury in all patients. All patients subsequently underwent embolization to complete angiographic stasis. Two patients had persistent bleeding following embolization. One of these patients required maintenance of his nasal packing for 7 days after embolization; no blood products were required during this time. The second patient's bleeding resolved following correction of his coagulopathy. No complications occurred in any of the patients. CONCLUSIONS: Transcatheter arterial embolization for epistaxis secondary to gunshot wounds is efficacious in the acute setting when conservative management fails.

Treatment of inferior vena cava anastomotic stenoses with the Wallstent endoprosthesis after orthotopic liver transplantation.

PURPOSE: To evaluate the efficacy of the Wallstent endoprosthesis for treatment of stenotic or occlusive inferior vena cava (IVC) lesions refractory to balloon angioplasty in patients after orthotopic liver transplantation. MATERIALS AND METHODS: Wallstent endoprostheses were implanted in six patients with IVC anastomotic stenoses or occlusions that were refractory to balloon angioplasty. Follow-up included both duplex ultrasound (US) and clinical evaluations. RESULTS: Ten stents were successfully implanted in six patients. Five of six patients (83%) demonstrated primary patency on duplex US for a mean period of 11 months (range, 4-17 months). One patient's symptoms recurred within 3 weeks after intervention. This patient underwent repeated stent placement. Follow-up duplex US in this patient demonstrated primary assisted patency at 7 months. Mean clinical follow-up was 12 months (range, 7-18 months). Other than the previously described case, no patient developed recurrent symptoms of IVC stenosis or occlusion. Two patients who experienced hemorrhagic complications secondary to anticoagulation were treated successfully. CONCLUSIONS: The Wallstent endoprosthesis is a useful adjunct for treatment of IVC stenosis or occlusions in patients who have undergone orthotopic liver transplantation when these lesions are refractory to simple balloon angioplasty.