Feasibility and Procedural Safety of alfapump System Implantation by IR: Experience from the MOSAIC Study, a Multicenter, Open-Label Prospective Study in Cirrhotic Patients with Refractory Ascites
Is alfapump implantation by IR technically feasible and procedurally safe?
Take away point
Alfapump placement by an interventional radiology approach is technically feasible.
Bendel, E. C., K. Sniderman, C. Shaw, R. T. Frederick, F. Wong, A. Sanyal, S. K. Asrani, P. S. Kamath, J. Capel and Z. J. Haskal (2020). "Feasibility and Procedural Safety of alfapump System Implantation by IR: Experience from the MOSAIC Study, a Multicenter, Open-Label Prospective Study in Cirrhotic Patients with Refractory Ascites." Journal of Vascular and Interventional Radiology 31(8): 1256-1262.e1253.
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Department of Radiology Mayo Clinic; Toronto General Hospital; Baylor University Medical Center; California Pacific Medical Center; Virginia Commonwealth University; Division of Interventional Radiology University of Virginia School of Medicine
Figure 1. The alfapump System implanted on the right side. (a) Schematic illustration. (b) X-ray image
The Sequana Medical alfapump is an implanted subcutaneous device that treats ascites by pumping peritonea l fluid into the bladder where it is excreted by voiding. The device consists of a pump component, a peritoneal catheter, and a bladder catheter. Current clinical data describes the device implantation procedure via a surgical approach. However, similar devices have been implanted by interventional radiologists. One aim of the MOSAIC trial (A Multicenter, Prospective, Open Label, Uncontrolled Feasibility Study to Assess the Safety and Effectiveness of an Automatic Low Flow Ascites Pump In Patients with Cirrhosis and Refractory or Recurrent Ascites) was to evaluate the technical feasibility and safety of alfapump implantation by interventional radiologists.
The authors evaluated 29 patients with cirrhotic refractory ascites from 6 different medical centers for procedural, periprocedural, and safety characteristics of IR alfapump implantation procedures. Technical success was 100%, defined as “the patient leaving the operating room with an implanted alfapump system that was actively pumping or pumping when activated or programed to do so”. 63% of the procedures were performed under general anesthesia and 37% were performed under local anesthesia. All patients received antibiotic prophylaxis.
83.3% of cases were performed according to the device instructions for use. The physician diverged from the instructions in five cases. The peritoneal catheter was implanted first in two instances to perform paracentesis during the procedure. Three cases presented procedural difficulty, of which two called for an additional incision for tunneling and one required a bladder catheter extension. One patient had a malfunctioning pump which was replaced during the procedure. One patient had post-op bleeding, which resolved after transfusion. The median hospital stay was 4 days.
27 patients were followed up at 3 months. One patient died secondary to cirrhosis and two patients had device explant because of cellulitis and wound dehiscence. 40 serious adverse events (SAE’s) were reported in 18 patients. Two SAE’s were classified as procedure related due to post-op bleeding and implant site abdominal pain and leakage. One patient developed bacterial peritonitis 26 days post-op, which was possibly procedure related. There were four re-interventions including one pump exchange the day of the procedure and three peritoneal catheter replacements for leaking, kinking, or dislodgment.
Overall, there was a 100% technical success rate, three procedure related SAE’s, four surgical revisions, and two explanations. The total adverse event rate was 31%. The study showed that alfapump implantation by IR is technically feasible.
The authors prospectively examined 29 cases of alfapump device implantation by interventional radiologists. The 100% technical success rate demonstrates that an IR approach is technically feasible. The overall adverse event rate was 31%. However, the authors described potential procedural changes such as increasing the initial pump volume and earlier pump initiation that may help to decrease adverse events related to pump pocket fluid accumulation. Nevertheless, the adverse event rate was comparable to or lower than reported in prior studies. As the authors mention, the study is limited by the small sample size, short follow up, and lack of control group. As the alfa pump device becomes more prevalent, subsequent larger studies will help further characterize the safety of an IR implantation and the risks and benefits compared to a surgical technique. Overall, alfa pump placement by interventional radiology is technically feasible and the alfa pump is a promising device for the treatment of recurrent ascites.
Maxwell Cretcher, D.O.
Integrated Interventional Radiology Resident, PGY-4
Department of Interventional Radiology
Dotter Interventional Institute, Oregon Health and Science University