Prospective evaluation of efficacy and safety of distal radial and radial artery access using a novel articulating-tip guidewire.

BACKGROUND: Guidewire-facilitated access to peripheral vessels is commonplace in vascular access, but guidewire insertion into small vessels, such as the radial and distal radial arteries, can still be challenging. Failure to gain access on the first attempt may contribute to increased risks of procedural complications, such as vessel dissection, spasm, and occlusion. This research assessed the safety and efficacy of radial and distal radial artery access using a novel, FDA-cleared, small-core-diameter guidewire with an articulating tip, under ultrasound guidance. METHODS: This was a prospective, single-arm, single-center trial. Patients in need of vascular access were screened for participation and enrolled in the study. Guidewire insertion was attempted by four physicians (three interventional radiologists and an interventional nephrologist) at 162 arterial sites-65 radial and 97 distal radial, having a mean diameter of 2.0 mm. RESULTS: First-attempt successful placement of the guidewire in the artery occurred at 87.6% of access sites (142/162) and differences in the success rate between the radial and distal radial arteries or between vessels with diameter smaller or larger than 2 mm were not observed (62/68 and 67/77, respectively; p = 0.6). Four of the five reported adverse events were unrelated to the study device or procedure. Two of the three distal radial artery spasms occurred before the guidewire was used. The other two events were a radial artery spasm, and a distal radial artery site hematoma. All adverse events resolved spontaneously. CONCLUSIONS: First-attempt placement of a novel articulating tip guidewire in the radial and distal radial arteries occurred at a high rate in our study and was not associated with safety concerns.

Staphylococcus aureus accumulation at the tip of hemodialysis catheters with or without tip side holes in catheter related bloodstream infection in a large animal.

BACKGROUND: Eighty percent of hemodialysis patients start their dialysis with a tunneled hemodialysis catheter. Catheter related bacteremia is the second most common cause of death in these patients. Side holes near the tips of the tunneled cuffed central venous catheters are associated with accumulation of thrombus, which can lead to catheter dysfunction and, possibly, also to catheter-related infection. To assess the hypothesis that a catheter without side holes would be associated with less bacterial growth, this study compared the susceptibility of a side-hole-free catheter to accumulation of pathogenic bacteria at the catheter tip with that of two catheters which have side holes. METHODS: Eight tunneled cuffed double-lumen central venous catheters were inserted into both jugular veins of four sheep; one side-hole-free and one control catheter with side holes at the tip in each animal. Staphylococcus aureus bacteria were then infused intravenously to cause bacteremia. Six hours later, the catheters were removed, the clots that accumulated in their tips were collected and cultured, and the bacterial colonies were counted after additional 12 h of incubation. RESULTS: Bacteria grew on culture plates seeded with the clot homogenate obtained from the tips of all catheters. The colony counts from the catheters with side holes at the tip exceeded the colony counts of bacteria accumulated in the tips of the side-hole-free hemodialysis catheters by one or more orders of magnitude, with a difference of at least two orders of magnitude observed in three of the four intra-animal comparisons. CONCLUSIONS: In paired intra-animal post-inoculation comparison made in this limited study, fewer colony forming units of pathogenic bacteria accumulated at the tip of the side-hole-free catheters than at the tips of the catheters which have side holes. This may translate to a decreased rate of catheter-related blood stream infections in the side-hole-free catheters.

Catheter-related blood stream infection in hemodialysis patients with symmetric tunneled non-side-hole hemodialysis catheters.

BACKGROUND: Tunneled hemodialysis catheter-related bloodstream infection is a major cause of morbidity and mortality in end-stage renal disease patients. Side holes positioned near the tip of catheters have been linked to formation of thrombi, which, in turn, have been implicated in predisposition to infection. In addition, side holes allow spillage of catheter locking solution, including antibiotics, thereby minimizing the lock solution's effect on the catheter tip. This study assessed the infection events that occurred in a series of hemodialysis patients using a non-side-hole catheter. METHODS: Over a period of 2 years, a novel symmetric-tip non-side-hole catheter was placed in 60 patients. Hemodialysis was performed thrice weekly. Prescribed dialyzer flows were 300-350 mL/min. Catheters were routinely locked with heparin 5000 units/mL between treatments. Patients were followed up for any catheter related complications, specifically infection events. RESULTS: Seven events of catheter-related bloodstream infection occurred for a rate of 0.76 events per 1000 catheter-days, with the first event occurring 9 weeks after insertion. These events were treated by locking the affected catheter with 2 g of clindamycin in 2 mL of heparin 1000 units/mL and administration of intravenous antibiotics, in most cases, for 7-14 days. Two catheters were removed due to infection. CONCLUSIONS: Catheter-related bloodstream infections with non-side-hole hemodialysis catheters do occur at a relatively low rate and in this initial preliminary study it seems that most of these infections can be successfully treated without removal of the affected catheters.

Pressure-Induced Fibroid Ischemia: First-In-Human Experience with a Novel Device for Laparoscopic Treatment of Symptomatic Uterine Fibroids.

The purpose of this study was to assess the feasibility of use of a novel uterine fibroid treatment device hypothesized to cause fibroid infarction by increasing intra-tumoral pressure. Between August 2019 and January 2020, 21 uterine fibroids were treated in 16 symptomatic pre-menopausal black women. Pelvic magnetic resonance imaging was performed before the procedure, a day after the procedure and at 1, 3, 6, and 12 months. The subjects were also followed for clinical outcomes and quality of life up to 12 months at a single investigational site. At 3 months, the mean reduction in the fibroid volume was 36.3% (P = .002). Incremental reduction in volume peaked at the end of the follow-up, at the 12-month mark (60.4%; P = .008). There were no procedures in which the users failed to perform laparoscopic pressure suturing of fibroids with the pressure-induced fibroid ischemia device. Improvement in the quality of life was evident in the Health-Related Quality of Life total, Energy/Mood, Control, and Sexual Function domains of the Uterine Fibroid Symptom and Quality of Life questionnaire at 3 months post-procedure. Unanticipated risks were not identified. Serious adverse events were not identified. The initial clinical assessment of the pressure-induced fibroid ischemia device supports feasibility of the approach and does not reveal serious safety concerns. Trial is currently being registered retrospectively (This was a feasibility study and therefore registration was not mandatory).

Clot accumulation at the tip of hemodialysis catheters in a large animal model.

BACKGROUND: The issue of side holes in the tips of the tunneled cuffed central venous catheters is complex and has been subject to longstanding debate. This study sought to compare the clotting potential of the side-hole-free Pristine hemodialysis catheter with that of a symmetric catheter with side holes. METHODS: Both jugular veins of five goats were catheterized with the two different catheters. The catheters were left in place for 4 weeks and were flushed and locked with heparin thrice weekly. The aspirated intraluminal clot length was assessed visually prior to each flushing. In addition, the size and weight of the clot were recorded upon catheter extraction at the end of the 4-week follow-up. RESULTS: The mean intraluminal clot length observed during the entire study follow-up measured up to a mean of 0.66 cm in the GlidePath (95% CI, 0.14-1.18) and 0.19 cm in the Pristine hemodialysis catheter (95% CI, -0.33 to 0.71), the difference being statistically significant (p = 0.026). On average, 0.01 g and 0.07 g of intraluminal clot were retrieved from the Pristine and GlidePath catheters, respectively (p = 0.052). CONCLUSION: The Pristine hemodialysis catheter was largely superior to a standard side hole catheter in impeding clot formation, and, contrary to the side hole catheter, allowed for complete aspiration of the intraluminal clot.

Initial Clinical Experience with a Symmetric Tip Tunneled Hemodialysis Catheter Without Side Holes.

The purpose of this article is to assess the performance and safety of a novel, symmetric, side-hole-free tunneled cuffed catheter hypothesized to sustain adequate flow without the need for side holes. Between November 2016 and January 2019, Pristine hemodialysis catheters were placed de novo in 45 end-stage renal disease patients (27 males and 18 females) at a single investigational site. Forty-one catheters were placed in the right and four in the left internal jugular vein. There were no incidents of insertion failure. Patients had dialysis three times per week and were followed at four investigational sites. Nominal catheter flows, incidence of poor flow, and catheter-related infections were recorded at each dialysis session and analyzed. The average follow-up time was 161.69 days for a total of 7116 catheter days. Nine patients died from reasons unrelated to the catheter and one patient switched to fistula. Four patients had poor flows necessitating catheter replacement. Four patients had catheter-related bloodstream infections which resolved with antibiotics. These equate to 0.56 events per 1000 catheter days. Catheter survival was 100%, 97.6%, and 89.7% at 30, 90, and 180 days, respectively. The initial clinical assessment of the symmetric Pristine hemodialysis catheter featuring a Y-tip devoid of side holes revealed good catheter performance and survival and a low complication rate.

A randomized comparison of a novel nitinol-frame low-dose-copper intrauterine contraceptive and a copper T380S intrauterine contraceptive.

OBJECTIVE: We sought to compare VeraCept (VC175), a novel nitinol intrauterine contraceptive (IUC) with 175 square-mm of copper surface area, to a copper T380S IUC. STUDY DESIGN: We enrolled parous women into a randomized subject-blinded comparison of VC175 and a copper T380S in a 2:1 fashion at a single clinic. The primary outcomes were total adverse events and continuation at 12 months. We also examined pain on insertion, ease of placement, expulsion, tolerability and pregnancy. Subjective ratings were on a 5-point Likert scale (0, no pain to 5, worst pain). We followed subjects through 24-month follow-up. RESULTS: We enrolled 300 women with 199 randomized to VC175 and 101 to the T380S. Insertion was successful in 198 subjects for VC175 and 100 for the T380S. Mean age was 25 years (range 18, 41), and median parity was 2 (range 1, 8), with 39% having only had Cesarean deliveries. No subjects developed clinical infection or reported serious adverse events. In the VC175 and T380S groups, mean pain at insertion was 1.4 and 2.4, respectively (p<.01). At the 12-month primary endpoint for VC175 and T380S, respectively, continuation was 84% and 68% (p<.002) with expulsions in 5.0% and 12.0% (p<.05) and removal for pain/bleeding in 3.5% and 17.0% (p<.01). At the 24-month visit for VC175 and T380S, respectively, continuation was 77% and 62% (p<.02 by log-rank). One ectopic pregnancy was identified at the 12-month follow-up in a VC175 user. No other pregnancies were diagnosed. With 297.3 and 132.4 woman-years, pregnancy rates were 0.3 and 0.0 per 100 woman-years for VC175 and T380S, respectively. CONCLUSIONS: VC175 resulted in less pain at insertion, fewer expulsions and higher total continuation than the T380S, with similar contraceptive efficacy. IMPLICATIONS: VC175 is a promising new intrauterine copper contraceptive on a nitinol frame that warrants further clinical trials.

Histologic findings after mechanochemical ablation in a caprine model with use of ClariVein.

OBJECTIVE: The use of foam and liquid sclerotherapy for the treatment of varicose veins and underlying venous reflux is widespread. A novel device, the ClariVein Occlusion Catheter (Vascular Insights LLC, Madison, Conn), has been the subject of several clinical trials in humans. We report the initial histologic results obtained with use of the device in a caprine vein model. METHODS: A total of 11 male goats (12 veins) underwent minimally invasive procedures. Unilateral mechanochemical ablation of the lateral saphenous vein by the ClariVein Occlusion Catheter with an E-140° tip was performed under fluoroscopic guidance in five veins with 5 mL of 1.5% sodium tetradecyl sulfate (STS) and in one vein with 5 mL of 0.9% saline. The remaining six received injection sclerotherapy with 5 mL of 1.5% STS or 0.9% saline. All subjects were assessed with ultrasound before the procedure and intermittently afterward during a period of 12 weeks. Subsequent termination was immediately followed by necropsy and histologic examination of the treated veins. RESULTS: Complete occlusion of the lateral saphenous vein was observed in all subjects treated with ClariVein and STS, whereas complete patency was noted in all other treatment modalities. Histologic staining with hematoxylin and eosin and Masson trichrome stain revealed total fibrotic sealing with extensive collagen production in all ClariVein/STS veins. A statistical significance was observed in the difference in the number of occluded veins between subjects treated with ClariVein/STS and those treated by injection sclerotherapy (Fisher exact test, P < .01). CONCLUSIONS: The ClariVein Occlusion Catheter with 1.5% STS can be used to achieve complete mechanochemical ablation of the lateral saphenous vein in a caprine model. The evidence in this report can be used to justify the device's use for the treatment of the great saphenous vein in subsequent human clinical trials.

Power injection of iodinated intravenous contrast material through acute and chronic hemodialysis catheters.

PURPOSE: End-stage renal disease patients with hemodialysis catheters in need of contrast enhanced imaging studies often have limited peripheral venous access. In this study we aimed to determine pressures generated in hemodialysis catheters during power injection of computed tomography (CT) contrast media. METHODS: Three different chronic hemodialysis catheters and two acute hemodialysis catheters were included in this study. All catheters were evaluated in vitro. A total volume of 120 cc of CT contrast material was injected at rate of 10 cc/s using a power injector. The catheters were connected to the power injector using a standard connecting tubing. Pressures were simultaneously measured in the power injector as well as in the hemodialysis catheters. RESULTS: The maximal measured pressures during injection in the power injector averaged 338 PSI (SD ± 8.7 PSI). The maximal measured pressure in the dialysis catheters ranged between 9.17 and 21.2 PSI. Pressures averaged 14.02 PSI (SD ± 3.34 PSI). The average pressure in the power injector was over 23 times higher than the pressure recorded at the hemodialysis catheter. None of the catheters ruptured or deformed during testing. CONCLUSIONS: Pressures measured in hemodialysis catheters during power injection are lower than currently believed and markedly lower than the pressures recorded in the power injector. Standard hemodialysis catheters are likely to be amenable to power contrast injection in hemodialysis patients who have limited venous access. In vivo studies are necessary to confirm these findings.

Previous PICC placement may be associated with catheter-related infections in hemodialysis patients.

BACKGROUND: Catheter-related infections (CRIs) are a significant source of morbidity and mortality in hemodialysis patients. The identification of novel, modifiable risk factors for CRIs may lead to improved outcomes in this population. Peripherally inserted central catheters (PICCs) have been hypothesized to compromise vascular access due to vascular damage and venous thrombosis, whereas venous thrombosis has been linked to the development of CRIs. Here we examine the association between PICC placement and CRIs. METHODS: A retrospective review was performed of all chronic hemodialysis catheter placements and exchanges performed at a large university hospital from September 2003 to September 2008. History of PICC line use was determined by examining hospital radiologic records from December 1993 to September 2008. Catheter-related complications were assessed and correlated with PICC line history. RESULTS: One hundred eighty-five patients with 713 chronic tunneled hemodialysis catheter placements were identified. Thirty-eight of those patients (20.5%) had a history of PICC placement; these patients were more likely to have CRIs (odds ratio = 2.46, 95% confidence interval = 1.71-3.53, p < .001) compared with patients without a history of PICC placement. There was no difference between the two groups in age or number of catheters placed. CONCLUSION: Previous PICC placement may be associated with catheter-related infections in hemodialysis patients.

VenaTrac™ device for over-the-wire placement of chronic dialysis catheters.

PURPOSE: The VenaTrac™ is designed for exchange and primary placement of chronic tunneled hemodialysis catheters over a wire. It occludes both lumens of the catheter for the purpose of reducing the risk of air embolism and blood loss. The purpose of this paper is to report our experience with the use of this device. METHODS: A retrospective review of chronic hemodialysis dialysis catheters exchanges over a 30-month period was performed. Two hundred and ninety-seven over-the-wire catheter exchanges and 47 primary placements using the VenaTrac™ device were reviewed. In addition, 430 over-the-wire catheter exchanges without the use of the VenaTrac™ were reviewed. RESULTS: No insertional complications or air embolism occurred when using the VenaTrac™. Symptomatic air embolism was documented in 5 out of 430 catheter exchanges performed without the use of VenaTrac™ (1.2%). CONCLUSIONS: VenaTrac™ over-the-wire insertion device demonstrated safe and reliable use with no incidence of air embolism.

Type 2 diabetes: Microvascular ischemia of pancreatic islets?

Hyperglycemia is a key factor in both beta cell death and dysfunction as well as in development of microvascular disease. The hypothesis described in this paper suggests that pancreatic microvascular endothelial dysfunction and subsequent microvascular disease of the pancreas causes islet ischemia. This subtle ischemia is the cause of initial dysfunction and subsequent apoptosis of B cells which is preceding development of type 2 diabetes. Moreover, the subtle beta cell ischemia will continue to diminish the beta cells' ability to secrete the increasing amount of insulin needed as the insulin resistant state progresses into type 2 diabetes. This vicious cycle might perpetuate type 2 diabetes.

Comparison of four embolic materials at uterine artery embolization by using postprocedural MR imaging enhancement.

PURPOSE: To test the hypothesis that not all embolic materials are equivalent by using postprocedural magnetic resonance (MR) imaging enhancement of uterine fibroids in patients treated with uterine artery embolization (UAE). MATERIALS AND METHODS: Approval and a waiver of consent from the institutional human investigations committee was received for this study. The study was HIPAA compliant. A total of 84 women who underwent 6-month MR imaging follow-up constituted this retrospective study. Within this group, 25 women were treated with Contour polyvinyl alcohol (PVA) particles, 23 were treated with Contour SE particles, 19 were treated with Embosphere microspheres, and 17 were treated with Bead Block microspheres. Pre- and postprocedural MR imaging results were analyzed for the total number of fibroids present in the uterus of each patient and for the percentage of individual fibroid enhancement. Enhancement of individual fibroids was measured with quartile intervals. Greater than 25% residual enhancement of a fibroid after embolization was considered an incomplete infarction. The overall percentage change in enhancement was calculated for each patient. Bivariate analysis by using generalized linear modeling and one-way analysis of variance was used to assess differences in infarction with different embolic materials. RESULTS: Among patients treated with Contour and Embosphere, there was a mean reduction in enhancement by 76.60% and 83.07%, respectively, compared with a mean reduction of 52.53% and 49.78% in patients treated with Bead Block and Contour SE, respectively. There was a significant difference in postembolization enhancement between Bead Block and Embosphere, Bead Block and Contour, Contour SE and Embosphere, and Contour SE and Contour. CONCLUSION: Patients treated with Bead Block or Contour SE demonstrated a reduced degree of infarction at follow-up MR imaging compared with patients treated with Contour or Embosphere.

Selecting optimal hemodialysis catheters: material, design, advanced features, and preferences.

Hemodialysis catheters are a necessary evil. They provide an immediate and effective lifeline for hemodialysis patients, and their use is steadily increasing. This increasingly important role has lead to the development of many generations of dialysis catheters. Some aspects of novel designs have shown potential to reduce complications, while others provide options for physician insertion preference. The two major biomaterials for catheter construction are currently polyurethane and silicone, while copolymers such as carbothane are becoming more widespread. Catheter coatings such as heparin, antibiotics, and silver ion are designed to minimize thrombosis and infection. Finally, many lumen and tip designs are also available. These new features were designed to address common problems, including maintenance of adequate flow rate and prevention of thrombosis, fibrin sheath, and catheter-related infection. However, reliable data directly comparing these different designs and coatings are currently lacking. This communication reviews current hemodialysis catheters, including materials, design, and advanced features.

Clinical outcome of the Tal Palindrome chronic hemodialysis catheter: single institution experience.

PURPOSE: To report the authors' clinical experience with the Tal Palindrome chronic dialysis catheter with a symmetric tip. MATERIALS AND METHODS: During a 39-month period, 126 Palindrome catheters were placed consecutively in 85 patients. Follow-up was available for 115 catheters. Insertion complications, patency, catheter-related bacteremia, exit site infections, and reasons for catheter removal were recorded. The patient's initial cause of end-stage renal disease, underlying diseases, and site of access were recorded as well. RESULTS: Patient ranged in age from 35 to 91 years (median, 69 years). Fifty percent of patients had diabetes. One hundred twenty-six Palindrome catheters were placed for a total of 12,046 catheter-days. The technical success rate of catheter placement was 100%. The average catheter indwell time was 105 days (range, 1-673 days). Catheters were inserted via the right (n = 107) or left (n = 19) jugular vein in all patients without insertional complication. Catheter-related infections occurred in 16 of the 115 catheters (13.9%) during the study period and culture-proved bacteremia occurred in four (3.5%). Seven exit site infections were recorded, and 10 catheters (8.7%) developed fibrin sheaths that necessitated catheter exchanges. CONCLUSIONS: Clinical experience with the Tal Palindrome hemodialysis catheter demonstrated safe and reliable use with low infection rates.

Comparison of MRI outcomes of uterine artery embolization for uterine leiomyoma using tris-acryl gelatin microspheres, polyvinyl alcohol spheres, and polyvinyl alcohol particles.

OBJECTIVE: Comparison of recurrence of magnetic resonance imaging (MRI) enhancement of uterine fibroids treated with uterine artery embolization (UAE) among embolic agents: polyvinyl alcohol (PVA), spherical PVA (SPVA), and tris-acryl gelatin microspheres (GM). METHODS: Pre/post-UAE gadolinium-enhanced MRIs were evaluated for residual enhancement of fibroids after UAE. Data were analyzed using 2-tail Fisher exact test to determine the likelihood of recurrence of enhancement post-UAE among embolic agents. RESULTS: One hundred one women underwent UAE. A total of 24 (41%) of 59 embolized with PVA, 18 (75%) of 24 with SPVA, and 4 (22%) of 18 with GM showed residual enhancement in some or all fibroids. Statistically significant differences in presence of residual enhancement on follow-up were found between SPVA and PVA (P = 0.0072), and SPVA and GM (P = 0.0015), but not between PVA and GM (P = 0.1756). CONCLUSIONS: Patients embolized with SPVA have a higher risk of having residual enhancement on follow-up MRI than those embolized with PVA or GM.

Fibroid-induced acute urinary retention: treatment by uterine artery embolization.

A 39-year-old gravida 2 para 2 woman presented to our Hospital's Emergency Department with complaints of difficulty voiding. She had an enlarged leiomyomatous uterus, for which she was not receiving any current treatment. A Foley catheter placed yielded 1,500 cc of clear yellow urine; however, the patient remained Foley-dependent for 2 weeks until she underwent uterine artery embolization (UAE). Twenty-four hours afterwards, the Foley catheter was removed and the patient spontaneously voided with negligible post-void residual. There was no recurrence of urinary retention or development of any other urinary symptoms during the outpatient follow-up period. Repeat pelvic magnetic resonance imaging (MRI) 1 week after UAE showed negligible reduction in the size of the fibroids and uterus in comparison with a pre-procedure MRI. The Vascular Steal Theory, first presented in this paper, discusses this improvement in symptoms without significant change in size.

Three-dimensional anatomy of the left central veins: implications for dialysis catheter placement.

PURPOSE: To define the three-dimensional anatomy of the left central veins and the implication for left-sided dialysis catheter placement. MATERIALS AND METHODS: Images from 30 consecutive patients undergoing computed tomography (CT) pulmonary angiography were reconstructed to depict the central venous anatomy. The reconstructed images were analyzed for parameters that could influence dialysis catheter placement. In particular, the cross-sectional diameters of the left brachiocephalic vein were measured, as well as the angulation between the left internal jugular vein and brachiocephalic vein, the angulation between left brachiocephalic vein and superior vena cava, and the angulation of the left brachiocephalic vein in the axial plane as it crosses the mediastinum. RESULTS: The cross-sectional diameters of the left brachiocephalic vein did not change significantly as it traversed the mediastinum. The mean cross-sectional diameters were 11 (+/-5.2) x 12 (+/-5.1) mm for the peripheral, 13 (+/-5.0) x 13 (+/-4.8) mm for the mid, and 13 (+/-4.6) x 14 (+/-4.5) mm for the central left brachiocephalic vein. The angulation between the left internal jugular and brachiocephalic vein measured 117 degrees (+/-11), the angulation between the left brachiocephalic vein and the superior vena cava measured 116 degrees (+/-7), and the angulation of the left brachiocephalic vein as it traverses the aorta and left brachiocephalic artery measured 106 degrees (+/-9). CONCLUSIONS: A sharp angulation of the left brachiocephalic vein as it drapes over the aorta or arch vessels is a common anatomic finding. This angulation is not apparent on frontal projection radiographs or venograms. A hemodialysis catheter torqued over this angulation could contact the vessel wall and lead to endothelial irritation. Further study may help define whether this contributes to the higher complication rates associated with left-sided catheters.