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.

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.

Stent-grafts for de novo TIPS: technique and early results.

PURPOSE: To evaluate the potential benefits of placing a polytetrafluoroethylene (PTFE)-covered stent-graft during initial creation of a transjugular intrahepatic portosystemic shunt (TIPS) in clinical practice. MATERIALS AND METHODS: De novo TIPS were created with a PTFE stent-graft in four male and four female patients with symptomatic portal hypertension awaiting liver transplant. Their ages ranged from 35 to 62 (mean, 47) years. Patients were followed with TIPS ultrasound (US) and/or venography until liver transplantation or death; one remains under active study. Six recovered specimens underwent gross and microscopic evaluation. RESULTS: All TIPS placements were successful. Six shunts were primarily patent, with a mean patency of 289 days, through completion of the study. Five were found to be patent at transplant and one was found to be patent at autopsy. Explant evaluation revealed a smooth, thin layer of neointima and exclusion of biliary secretions. Three patients developed a total of four stenoses (one tandem lesion) during follow-up, leading to revision in two patients. Mean primary and total patency in these patients was achieved after 279 and 463 days, respectively. A previously occult moderate stenosis was detected after explant in another patient. Only one (nonsignificant) stenosis clearly developed in an area covered by PTFE. CONCLUSION: Placement of a de novo PTFE stent-graft during TIPS creation is feasible and may extend primary shunt patency. Appropriate positioning of the stent-graft is critical.

Percutaneous transjugular kidney biopsy in swine with use of a side-cutting needle with a blunt-tipped stylet.

PURPOSE: To evaluate a new 19-gauge blunt-tipped, side-cutting, single throw transjugular biopsy needle for transvenous kidney biopsies. MATERIALS AND METHODS: Transjugular transvenous kidney biopsies were performed with a modified 70-cm biopsy needle utilizing fluoroscopic guidance in nine swine. Three tissue specimens were obtained with four biopsy device passes in five animals and three biopsy device passes in four animals. Renal arteriography and venography were performed immediately before and after renal biopsy. Five animals were killed immediately after biopsy. Four animals were allowed to recover and underwent arteriography and venography prior to being killed, which varied from 1 to 6 weeks. Gross and histologic examinations of the biopsied kidney were performed after euthanasia. A pathologist reviewed all biopsy specimens for quality based on the number of glomeruli present. RESULTS: Results of immediate and delayed arteriography and venography were normal in all cases. Histologic evaluation of all biopsy specimens demonstrated a range of two to 13 glomeruli per sample (mean, 6.5), with successful acquisition of the cortex. In one animal killed immediately after biopsy, a small subcapsular hematoma was present. CONCLUSION: The 19-gauge, side-cut biopsy needle with a blunt-tip stylet proved to be efficacious for obtaining renal cortical samples in right swine kidneys via a transjugular approach.

Activation of proximal tubular Na(+)-H+ exchange by angiotensin II.

Stimulation of Na(+)-H+ exchange by angiotensin II (ANG II) was characterized in renal proximal tubular cells. Rabbit proximal nephron segments were incubated in the presence or absence of ANG II (5 x 10(-10) M), after which brush-border membrane vesicles (BBMV) were isolated and assayed for Na(+)-H+ antiporter activity using the acridine orange technique. Both the affinity (for sodium) and capacity of the carrier were elevated significantly (P less than 0.05) within 15 min of incubation with ANG II. To determine whether the stimulation of transport capacity involved a change in Na(+)-H+ antiporter density in the luminal membrane, binding of tritiated 5-(N-methyl-N-isobutyl)amiloride ([3H]MIA) was measured in BBMV derived from control and ANG II-treated nephron segments, following maximal stimulation. This demonstrated a significant (P less than 0.05) increase in the maximal specific binding (Bmax) of [3H]MIA binding in the ANG II-treated group compared with control, of a magnitude sufficient to account for the observed change in maximal velocity (Vmax). The data indicate that the Vmax effect is caused by an apparent increase in the number (density) of active Na(+)-H+ carriers present in the luminal membrane. Finally, to test the possibility that the observed kinetic change involves an exocytic mechanism, the effect of colchicine on ANG II-stimulated antiporter activity was examined. The increase in Vmax due to ANG II was blocked by the addition of 0.5 mM colchicine to the incubation medium, whereas colchicine alone had no significant effect on the Vmax of Na(+)-H+ kinetics.(ABSTRACT TRUNCATED AT 250 WORDS)