Alfapump: Refractory Ascites – and no liver transplant in sight – If in doubt – pump it out?

Ascites in patients with cirrhosis can be managed in most patients with salt restriction and diuretics. Patients who are truly refractory to diuretics have pre-hepatorenal syndrome and a poor prognosis unless transplanted. A special conundrum are patients with large varices that are on beta-blockers to prevent variceal bleeding because the beta-blockers can decrease renal perfusion and contribute to the development of hepatorenal syndrome. The mainstay of management for refractory ascites are liver transplantation, and for those on the waiting list or who are not candidates, frequent therapeutic paracentesis, often every 2 weeks. Transjugular intrahepatic portosystemic stent shunt (TIPS) placement with its risk of hepatic encephalopathy is currently still only recommended for carefully selected patients who cannot tolerate the repeated paracentesis, however, evidence is accumulating that TIPS may confer a survival advantage over frequent paracentesis [i].

1980s – LeVeen and Denver – Pumping the ascites from the abdominal cavity into the circulation

1980s shunts: Ascites flows through a tunneled catheter to the vena cava. No pump.

Many decades ago saw the advent of the LeVeen and Denver shunts. The principle is simple. The ascites, already under pressure, is channeled via a subcutaneous shunt that has a one-way valve through the internal jugular vein back to the general circulation. Malcolm Stanley, one of my teachers, and his coworkers established in a large study published in NEJM that peritoneovenous shunts were effective but did not confer a survival advantage[ii]. Unfortunately, the peritoneovenous shunt were bedeviled by frequent problems, clogging being a frequent one. Perhaps the flow was too slow?

Ca. 2018 – Alfapump – Pumping the ascites from the abdominal cavity into the bladder

The alfapump uses a small microprocessor-controlled pump to move the ascites into the bladder.

The alfapump (Sequana Medical AG, Zurich, Switzerland) is an implanted closed pump system that transports ascites from the peritoneal cavity to the urinary bladder via firstly a tunnelled peritoneal catheter and then a tunnelled bladder catheter. It is available in several European countries but plans for the US are not known.  The alfapump has a programmable microprocessor that controls a small pump that is powered by a battery that is wirelessly charged through the skin. Data of it performance are collected and send through the cellular network to data centers. A recent multi-center randomized trial comparing alfapump with large volume paracentesis showing improved nutritional parameters and quality of life [iii]. In a published analysis of prospective registry data the effectiveness of the alafalump was confirmed, but there were significant procedure-related complications requiring reintervention or explanation of the device. The most common technical problem was blockage of the peritoneal catheter, somewhat reminiscent of the problems encountered with peritoneovenous shunting. The authors conclude that technical and procedural improvements are required to reduce the rate of adverse events and reinterventions [iv]. A lot has changed in the 40 years since the advent of the LeVeen and Denver shunts. The continuously collected feedback about pump function is a feature that should lead to a more effective redesign in a shorter period of time. To be continued…

References:

[i] Trieu H, Lee EW, Kee ST. Transjugular Intrahepatic Portosystemic Shunt in Ascites: Updates. Digestive Disease Interventions. 2017 Dec 26

[ii] Stanley MM, Ochi S, Lee KK, Nemchausky BA, Greenlee HB, Allen JI, Allen MJ, Baum RA, Gadacz TR, Camara DS, Caruana JA. Peritoneovenous shunting as compared with medical treatment in patients with alcoholic cirrhosis and massive ascites. New England Journal of Medicine. 1989 Dec 14;321(24):1632-8.

[iii] Bureau C, Adebayo D, de Rieu MC, Elkrief L, Valla D, Peck-Radosavljevic M, McCune A, Vargas V, Simon-Talero M, Cordoba J, Angeli P. Alfapump® system vs. large volume paracentesis for refractory ascites: A multicenter randomized controlled study. Journal of hepatology. 2017 Nov 1;67(5):940-9.

[iv] Stirnimann G, Berg T, Spahr L, Zeuzem S, McPherson S, Lammert F, Storni F, Banz V, Babatz J, Vargas V, Geier A. Treatment of refractory ascites with an automated low‐flow ascites pump in patients with cirrhosis. Alimentary pharmacology & therapeutics. 2017 Nov 1;46(10):981-91.

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