Bacterial colonization of chronic hemodialysis catheters: Evaluation with endoluminal brushes and heparin aspirate.

Tunneled catheters serve as interim access during maturation of a graft or fistula, or as a permanent vascular access in those patients who have exhausted their traditional access sites. However, bacteremia rates are high in patients with chronic catheters and indiscriminate removal of catheters during bacteremia increases morbidity and costs. A method to identify whether a catheter was colonized with the offending bacteria, without requiring catheter removal is desirable. We compared endoluminal brushing and heparin aspiration, to detect catheter colonization, in 24 asymptomatic patients undergoing elective tunneled hemodialysis catheter removal. The incidence of catheter colonization was highly correlated with catheter duration of inverted exclamation markY 30 days (p=0.03). Staphylococcus epidermidis represented 68% of the organisms isolated. No other organism accounted for more than 7% of the total. Fifteen (62.5%) of the 24 catheters had positive cultures. Eleven of the catheters were positive by culture of heparin aspirate and eight were positive by endoluminal brushing. Only four of the catheters were positive by both methods. The arterial lumen was more likely to have positive cultures than the venous lumen using either method. In this prospective investigation of tunneled hemodialysis catheters in asymptomatic patients we have demonstrated that a heparin aspirate sample is more likely to detect catheter colonization than a sample obtained using an endoluminal brush. Furthermore, 75% of catheters present for more than 30 days were colonized. Further study is needed to determine if the heparin aspirate method could be used in patients with bacteremia to accurately identify catheters that need removal.

Complications related to percutaneous thrombectomy of hemodialysis grafts.

PURPOSE: To retrospectively review the complications reported during percutaneous thrombectomy procedures performed on polytetrafluoroethylene hemodialysis grafts. MATERIALS AND METHODS: A retrospective review revealed that 935 percutaneous thrombectomy procedures were performed at our institution between January 1993 and June 2001. The type and number of procedures include: Arrow PTD (527), pulse-spray with urokinase (240), Amplatz Thrombectomy Device (96), AngioJet (17), Oasis (15), Hydrolyser (10), Endovac (7), Lyse and Wait (7), Thrombex (6), Cragg brush (6), Castaneda brush (4). Complications were reported to have occurred in 31 patients. The radiology reports and medical records of these patients were reviewed. RESULTS: The overall complication rate was 3.3%. The type and number of complications included: rupture of a vein during angioplasty (13), severe cardiopulmonary distress (4), arterial emboli (4), rigors related to urokinase (3), minor bleeding (2), hypoxia with chest pain (2), other assorted complications (3). There was one death resulting from a fall from the angiography table immediately following the procedure. There were 12 minor complications, requiring minimal treatment, and 19 major complications that altered the course of the procedure or treatment of the patient. CONCLUSION: The most common complication was angioplasty-induced rupture of the vein or graft. The most severe complications occurred immediately following dislodgement of the arterial plug and were likely due to acute pulmonary embolization.

Vascular rupture during angioplasty of hemodialysis raft-related stenoses.

PURPOSE: To retrospectively determine the incidence and outcome of angioplasty-induced ruptures that occurred during treatment of hemodialysis graft-related stenoses. MATERIALS AND METHODS: During a five year period 1222 patients with dysfunctional or thrombosed polytetrafluoroethylene (PTFE) hemodialysis grafts underwent angioplasty procedures at our institution. Angioplasty-induced vascular ruptures occurred in 24 (2.0%) patients. The locations of these ruptures were: basilic vein (10), venous anastomosis (7), cephalic vein (5), brachial vein (1) and intragraft (1). The mean length of the treated stenoses was 2.4 centimeters. RESULTS: Manual compression was used to treat the vascular rupture in ten patients. One patient was treated with endovascular balloon tamponade and one patient underwent stenting of the rupture site. Despite the rupture, 15 patients had completion of the angioplasty procedure. In nine patients the procedure was abandoned due to persistent stenosis at the rupture site. There were no major complications as a result of these ruptures. Follow-up was available in ten of these patients. All ten underwent at least one successful hemodialysis treatment. In five of these patients the hemodialysis graft failed within 30 days after the rupture. The mean primary patency following rupture in the ten patients with follow-up was 87.5 days (range 5 - 225 days). CONCLUSION: The incidence of angioplasty-induced vascular rupture of hemodialysis-related stenoses is low and despite the injury, the majority (62%) of procedures can be completed. However, in our experience the long-term patency of the vascular access was suboptimal.

Air embolism during insertion of central venous catheters.

PURPOSE: To determine the clinical consequences of air embolism occurring during insertion of central venous catheters. MATERIALS AND METHODS: A computer search of our interventional radiology database revealed that 11,583 central venous catheters were inserted between January 1, 1995 and August 1, 2000: 7,178 were nontunneled and 4,404 were tunneled. Air embolism was reported to have occurred in 15 patients. Air embolization was recognized by audible air aspiration during catheter insertion or by fluoroscopic visualization of air within the right atrium or pulmonary artery. The radiology reports and medical records of these 15 patients were reviewed. RESULTS: All 15 patients had an air embolism occur during insertion of a tunneled central venous catheter. These included eight Ash catheters, five chest wall ports, one Tesio catheter, and one Pheres-Flow catheter. Four patients remained asymptomatic. Six patients had mild symptoms that quickly resolved with supplemental oxygen. Four had moderate symptoms that also resolved with supplemental oxygen. One patient died acutely as a result of the air embolism. CONCLUSION: Air embolism is a rare but potentially fatal complication of central venous catheter procedures. In our series, all occurred during insertion of a tunneled catheter through a peel-away sheath. The administration of supplemental oxygen was an effective treatment in the majority of patients.

Flow in hemodialysis grafts after angioplasty: Do radiologic criteria predict success?

BACKGROUND: The anatomic success of percutaneous angioplasty of venous stenosis is determined by the improvement in cross-sectional diameter of the vessel. A successful outcome is defined as a residual stenosis of <30%. The purpose of this study was to determine whether the angiographic assessment of a venous stenosis correlates with the change in graft blood flow following angioplasty. METHODS: Twenty-two hemodialysis patients with decreased intragraft blood flow (<700 mL/min) underwent diagnostic fistulography and angioplasty. All grafts were patent at the time of the procedure. Intragraft blood flow was measured before and after angioplasty using the ultrasonic dilution technique. Change in graft blood flow after angioplasty was correlated to the morphologic changes of the treated stenosis. RESULTS: The mean preangioplasty and postangioplasty graft blood flows were 457 +/- 136 and 818 +/- 202 mL/min, respectively. The mean degree of stenosis before angioplasty was 74 +/- 15% and 18 +/- 14% after dilation (P < 0.001). The only variable that significantly correlated with postangioplasty blood flow was preangioplasty flow (r2 = 0.22, P < 0.001). The postangioplasty blood flow was not significantly different than the highest recorded blood flow measured in that graft (798 +/- 213 mL/min, P = NS). There was no significant correlation between the change in blood flow and the change in percentage of stenosis. CONCLUSION: Following angioplasty of a venous stenosis, the graft blood flow is most closely predicted by the preprocedural blood flow and is similar to the highest recorded blood flow ever measured in that graft. Angiographic criteria to assess the success of angioplasty are not predictive of changes in blood flow.

Angioscopy.

Angioscopy provides a magnified, real-time, 360-degree view of the endoluminal surface of blood vessels, yielding unique information that is often complementary to conventional angiography. This unique perspective can significantly enhance one's perception and appreciation of endovascular disease. Although angioscopy is primarily used as a research tool, its ability to characterize accurately the morphology and color of atherosclerotic lesions may lead to improved treatment and better clinical outcomes.

Angioscopic observations after percutaneous thrombectomy of thrombosed hemodialysis grafts.

PURPOSE: To use angioscopy to evaluate and compare the amount of residual thrombus and endoluminal wall damage in hemodialysis grafts after percutaneous thrombectomy procedures. MATERIALS AND METHODS: Thirty-nine thrombectomy and angioscopy procedures were performed in 35 patients. Percutaneous thrombectomy methods included eight different mechanical thrombectomy devices and the "lyse and wait" technique. Videotaped images of 33 angioscopic examinations were independently reviewed by three radiologists. Two parameters-the amount of residual thrombus and degree of endoluminal wall damage-were scored on a scale of 1 to 5. Data were initially analyzed to validate the grading system and then further studied to compare the different thrombectomy techniques. RESULTS: The Spearman rank order analysis validated the data pertaining to the amount of residual thrombus (r = 0.71, P < .0001), but there was poor correlation between reviewers regarding the degree of endoluminal wall damage. Combined scores from three reviewers revealed that the Cragg brush and Percutaneous Thrombectomy Device (PTD) left the smallest amounts of residual thrombus. The other methods tested, listed by increasing amount of residual thrombus, were the Endovac, Hydrolyser, Amplatz Thrombectomy Device, AngioJet, Oasis, and the lyse and wait technique. There were two complications related to angioscopy procedures. CONCLUSION: Subjective observations reveal that wall-contact thrombectomy devices leave less residual thrombus than hydrodynamic devices, aspiration devices, or the lyse and wait technique.

Comparison of the angiojet rheolytic catheter to surgical thrombectomy for the treatment of thrombosed hemodialysis grafts. Peripheral AngioJet Clinical Trial.

PURPOSE: To compare the clinical effectiveness of the AngioJet F105 rheolytic catheter to that of surgical thrombectomy for the treatment of thrombosed hemodialysis grafts. MATERIALS AND METHODS: This was a multicenter, prospective, randomized trial comparing technical success, primary patency, and complication rates. A total of 153 patients were enrolled: 82 patients in the AngioJet group and 71 patients in the surgical thrombectomy group. Patient follow-up was performed 24-48 hours, 1 month, and 6 months after the procedures. RESULTS: Technical success, as defined by the patient's ability to undergo hemodialysis treatment, was 73.2% for the AngioJet group and 78.8% for the surgical thrombectomy group (P = .41). The primary patency rates of the AngioJet group were 32%, 21%, and 15% at 1, 2, and 3 months, respectively. The primary patency rates for the surgical group were 41%, 32%, and 26% at 1, 2, and 3 months, respectively. This difference approached statistical significance (P = .053). The groups had similar complication rates-14.6% in the AngioJet group and 14.1% in the surgery group-although the surgery group had more major complications (11.3%). In the AngioJet group, there was a transient increase in plasma-free hemoglobin, which normalized within 24-48 hours. CONCLUSIONS: The AngioJet F105 catheter provides similar clinical results when compared to surgical thrombectomy for the treatment of thrombosed hemodialysis grafts. The difference in patency rates between these two techniques approached statistical significance. In addition, results of both thrombectomy methods were inferior to those suggested by the Dialysis Outcomes Quality Initiative guidelines.

Initial performance of Tesio hemodialysis catheters.

PURPOSE: This retrospective study was performed to investigate the authors' clinical observations that suggest that Tesio hemodialysis catheters may initially have suboptimal blood flow rates, which improve spontaneously after several hemodialysis treatment sessions. MATERIALS AND METHODS: Sixty Tesio twin hemodialysis catheters were placed in 49 patients during a 2-year period. Thirty twin catheters were placed by radiologists, and 30 were placed by surgeons. The catheter blood flow rates and catheter line pressures, which were recorded during each of the first five hemodialysis treatment sessions, were reviewed and analyzed to determine the performance of each catheter during the first five hemodialysis treatments. In addition, the authors compared the site of catheter placement and responsible service (surgery or radiology) using this catheter performance data. RESULTS: Twenty-six catheters (43%) provided adequate blood flow (250 mL/min) throughout the first five hemodialysis sessions. Twenty-six catheters (43%) had inadequate or variable blood flow rates, some of which improved without intervention. Eight catheters (13%) required an intervention before the first five hemodialysis sessions had been completed. Right-sided catheters performed better than left-sided catheters. There was no difference in performance between catheters placed by surgeons and those placed by radiologists. CONCLUSION: This investigation supports the authors' suspicion that some Tesio catheters may have inadequate initial performance but the blood flows can improve, without intervention, during the first five hemodialysis sessions/2 weeks of use.

Percutaneous drainage of fluid collections in the extremities.

PURPOSE: To analyze the results of percutaneous drainage of fluid collections in the extremities. MATERIALS AND METHODS: From 1990-1997, 28 patients aged 14-90 years underwent percutaneous drainage of 33 fluid collections in the extremities; two patients underwent multiple drainages. Fluid collections were in the hip-groin area (n = 16), thighs (n = 6), buttocks (n = 6), knees (n = 3), calf (n = 1), and axilla (n = 1). Three intraarticular collections were included. The patients who had undergone prior procedures were eight who had undergone surgical drainage, 10 who had undergone needle aspiration, and one who had undergone surgical débridement. The two most common guidance methods of catheter placement were ultrasound localization and fluoroscopy. RESULTS: The average drainage duration was 18.2 days (range, 1-93 days). The estimated cavity sizes were 4-733 cm3. Purulent fluid was drained in 13 patients. Staphylococcus aureus was the most commonly identified organism (n = 9). Nine patients had postoperative lymphoceles; five of these patients underwent sclerotherapy. Two (7%) patients had two complications, one of which was major. Failure occurred in four (16%) of 25 patients; two needed repeat drainage for recurrence, and two needed subsequent surgery. Success could not be determined in three patients who were lost to follow-up. CONCLUSION: Percutaneous drainage of fluid collections in the extremities is an effective alternative to open-incision drainage in inpatients and outpatients.

Treatment of thrombosed hemodialysis access grafts: Arrow-Trerotola percutaneous thrombolytic device versus pulse-spray thrombolysis. Arrow-Trerotola Percutaneous Thrombolytic Device Clinical Trial.

PURPOSE: To evaluate a percutaneous thrombolytic device (PTD) designed for treating thrombosed hemodialysis access grafts. MATERIALS AND METHODS: To compare the PTD with pulse-spray pharmacomechanical thrombolysis (PSPMT) by using urokinase, 122 randomly chosen patients with synthetic, thrombosed hemodialysis access grafts from multiple centers prospectively underwent thrombolysis with the PTD (5-F, low-speed rotational mechanical device) or PSPMT. Major outcome variables included the procedure time, the immediate technical patency rate, the complication rate, and the 3-month patency rate. RESULTS: Sixty-four PTD and 58 PSPMT procedures were performed with intent to treat. The immediate technical patency rate was 95% (61 of 64 [PTD] and 55 of 58 [PSPMT]) in both procedures. Median procedure times were 75 minutes in the PTD group (range, 25-209 minutes) and 85 minutes in the PSPMT group (range, 50-273 minutes; P < .04). Major complications occurred in 8% (five of 64) of PTD procedures (none related to the PTD) and 9% (five of 58) PSPMT procedures (not significant). Two devices broke (one during training) with no clinical sequela. The 3-month primary patency rate was 39% (25 of 64) in the PTD group and 40% (23 of 58) in the PSPMT group (not significant). CONCLUSION: The PTD is safe and effective for treating thrombosed hemodialysis access grafts. The technical and long-term success rates are similar to those of PSPMT; procedure times are shorter.

Upper extremity central venous obstruction in hemodialysis patients: treatment with Wallstents.

PURPOSE: To determine the effectiveness of using Wallstents to treat subclavian or brachiocephalic venous obstruction after unsuccessful angioplasty, in patients undergoing hemodialysis. MATERIALS AND METHODS: Dialysis records, radiology reports, and procedural images of 20 hemodialysis patients who underwent Wallstent insertion into a subclavian (n = 11) or brachiocephalic (n = 9) vein were reviewed. Technical success and primary, assisted primary, and cumulative patency rates were calculated. RESULTS: Twenty-three Wallstents were inserted for stenosis (n = 18) or occlusion (n = 2). Technical success was 100%. Eight patients underwent 11 reinterventions to maintain patency of the Wallstent during the follow-up period. Patency rates of the Wallstent were (a) primary at 1 month, 3 months, 6 months, and 1 year: 90%, 67%, 42%, and 25%; (b) assisted primary at 3 months, 6 months, and 1 year: 88%, 62%, and 47%; and (c) cumulative at 3 months, 6 months, 1 year, and 2 years: 89%, 64%, 56%, and 22%. Considerable shortening of the stent occurred in five patients. One occurred immediately during the deployment procedure, but four were discovered weeks to months later. No other complications occurred. CONCLUSION: After suboptimal angioplasty, treatment of subclavian and brachiocephalic vein stenoses with a Wallstent can provide continued use of a hemodialysis access. Close clinical surveillance and multiple reinterventions are necessary to maintain Wallstent patency.