At the 2013 VEITHsymposium, Eugene J. Simoni, MD, presented results of the PEARL registry, which studied hemodialysis patients treated with mechanical thrombectomy. In the two-phase prospective registry, use of the AngioJet thrombectomy system (Bayer HealthCare) was examined in 145 patients at 19 centers. Vascular Disease Management spoke with Dr. Simoni about the results.
Q: Please give us an overview of the PEARL registry.
A: We looked at overall patency of grafts and fistulas after undergoing mechanical thrombectomy with the AngioJet catheter, and we also looked at the primary patency without any other interventions and the patency with other interventions but not clotting. What it boiled down to was that 76% of the grafts and fistulas functioned after a year, overall.
If grafts clotted again, we mechanically thrombectimized them again, or if there were malfunctions where patients needed treatment with angioplasty or stenting, that was done. Any graft that failed or underwent surgical thrombectomy was considered a graft occlusion failure.
The results were good: the primary patency after thrombectomy without any further intervention was 31% at 12 months, which I found to be extremely good. It was over 70% at 3 months whereas the Kidney Disease Outcomes Quality Initiative guidelines had around 40% patency without further intervention, so we’re well above these guidelines by doing it percutaneously. So this means that percutaneous mechanical thrombectomy of these grafts and fistulas with the AngioJet is as effective if not more effective than an open surgical procedure.
Q: What were the most promising results?
A: The most promising result was the overall patency of the fistulas and grafts over the length of time of the study. Not only does the thrombectomy work well but also the surveillance that the dialysis units are doing on these grafts picks up any narrowings earlier so they can be treated. The success of the mechanical thrombectomy is promising, and it is a benefit to the patient that they can receive treatment in an endovascular suite or radiology suite, because it’s easier to schedule the patient there than in an operating room. The procedures also are done mostly under local anesthesia with no sedation. And it’s a fairly quick procedure: the length of time needed for using AngioJet alone without thrombolytics is just over an hour, and adding thrombolytics doesn’t add much time. And it cleans out the graft fairly nicely. I think it does it as well if not better than a Fogerty catheter does.
Q: Were there any results that were surprising?
A: I think the most surprising result was that the success with native fistulas was just as good as with prosthetics. You would think the prosthetic would clean out easier than a native vein, which has varying sizes and diameters throughout depending on how much it dilates up from the fistula, but the patency results and the success rate was just as good; there wasn’t any significant difference between a graft and a native vein.
Q:What is the biggest challenge related to this therapy?
A:The most challenging thing is to keep these fistulas and grafts working. If you have a graft that clots and thromboses, and you do an open thrombectomy, you can pull the clot out, but if there’s narrowing or another problem in the graft sometimes you’ll still have clot around there because it’ll hang up on the narrowing. Mechanical thrombectomy will remove the clot from narrowed areas as well, leaving just the stenotic area, which you can treat. And I think it cleans the vessels out better with the pressure of the saline fragmenting the clot and aspirating it out from the catheter.
Q: Any final comments?
A: There’s really a low risk associated with this therapy; the complications we saw were very minor, so it’s not a high complication procedure: only less than 2% of patients had any adverse events from this procedure.
Editor's note: Eugene J. Simoni, MD, is a vascular surgeon at the Penn State Milton S. Hershey Medical Center in Hershey, Pennsylvania. Dr. Simoni is a primary investigator in the PEARL registry. Dr. Simoni also reports membership on the steering committee at Bayer HealthCare.