Preliminary evaluation of a valved introducer sheath for the insertion of tunneled hemodialysis catheters.

This brief technical report describes our initial experience using the FlowGuard valved introducer sheath during the insertion of tunneled hemodialysis catheters in 15 patients. The incorporation of a silicone valve into the introducer sheath is intended to minimize blood loss and decrease the risk of air embolism during the catheter insertion procedure. Our preliminary experience demonstrated that the FlowGuard sheath is a substantial improvement when compared to standard introducer sheaths. However, an asymptomatic air embolus did occur in one patient. This article describes several caveats for the use of this new product.

Use of a catheter-based system to measure blood flow in hemodialysis grafts during angioplasty procedures.

PURPOSE: The goals of this investigation were to evaluate the accuracy and reliability of the Angioflow meter system with use of in vitro and in vivo methods and to compare it to the standard Transonics HD01 system in a clinical setting. MATERIALS AND METHODS: The Angioflow meter system consists of a 6-F endovascular catheter and a laptop computer containing proprietary software for this application. Bench-top testing with use of a flow model was performed to determine the accuracy of the Angioflow meter system. Initial in vivo studies were performed with use of an animal model to assess the endovascular performance of the Angioflow meter system. Subsequently, a human clinical trial was performed to compare the Angioflow meter to the standard Transonics HD01 system. Twenty-five patients with dysfunctional (<600 mL/min) hemodialysis grafts were referred for fistulography and angioplasty. Intragraft blood flow measurements were obtained before and after angioplasty with use of both the Angioflow meter system and the Transonics HD01 system. A comparison of the two systems was performed. RESULTS: Bench-top testing and animal studies demonstrated an excellent (r =.98) correlation between the measurements of the Angioflow meter and volumetric flow measurements. In the clinical trial, there was reasonable correlation (r =.72) between the blood flow measurements obtained with use of the Angioflow meter and Transonics HD01 system. The reproducibility of consecutive measurements with the Angioflow meter was excellent (r =.98). The mean increase in intragraft blood flow after angioplasty was 320 mL/min. CONCLUSION: The Angioflow meter is an accurate and reliable endovascular device for measuring intragraft blood flow during interventional procedures. Use of this catheter-based system should prove beneficial for quantifying the success of endovascular interventions, the assessment of arterial inflow, and identification of inconspicuous lesions.