Dirk M Hentschel (Harvard Medical School, Cambridge, USA), president of the Vascular Access Society of the Americas (VASA), has presented on the new Nephrodite Holly implantable device for continuous haemodialysis. Designed as an “implantable continuous dialysis hemofiltration device blending haemodialysis and peritoneal dialysis in one device,” it purports to offer patients more freedom than both in-centre and home dialysis treatments. Hentschel disclosed that he was a member of Nephrodite’s advisory board and that he held equity in the company as well as in BluegrassVascular.
The presentation at VEITHsymposium (15–19 November, New York City, USA) began with a question—“why bother?” What makes an implantable device worth the investment for clinicians and their patients? The answer was multi-pronged, with Hentschel acclaiming the mobility gained and time saved by utilising products like Holly. The core of Holly’s utility is the freedom it gives to patients, he said. The ambition behind the device is to provide something “approaching continuous dialysis,” he continued, and that patients using the device “should reach stage 4 CKD kidney function (eGFT > 15ml/min)”. He outlined the core concepts behind the device, including miniaturisation of dialysis technology to allow it to be portable as well as the reuse of dialysate.
Hentschel was not afraid to outline the many challenges in designing a successful implantable dialysis device. Building a body-device connection was among them, as were the multiple risks associated with use of the device, which included both thrombosis and infection. There were also questions, Hentschel said, about how best to control the parameters of dialysis on the device after implantation.
He had answers to these questions, however. For controlling dialysis, he mooted the twin possibilities of an external device for controlling dialytic parameters as well as an internal one requiring a “biological kidney equivalent.” Holly itself, he said, operates on a hybrid system blending both of these approaches. Using a catheter coming out of the skin, it will connect to a wearable bag of dialysate fluid which patients can change themselves every four to six hours. This will give patients a new level of freedom even compared to existing home dialysis systems, Hentschel suggested.
Holly’s system brings its own challenges, however. Hentschel sketched out several, including those brought by the external reservoir connected to the system. The membrane of the device is subject to ageing and may mean it needs to be replaced, he said, while control of the micropump at the centre of Holly’s design also demands a solution and dialysate needs to be monitored.
