RENAL3: Hybrid Concentration Method of Ascites Filtration and Concentration Equipment for Cell-free and Concentrated Ascites Reinfusion Therapy

Study: As a safe and effective treatment for refractory ascites, more than 30,000 cases of Cell-free and concentrated ascites reinfusion therapy (CART) are performed annually in Japan. In ascites processing, concentration has been performed at a fixed concentration ratio (constant ratio concentration) with a standard value of 10-fold concentration. However, as the main target disease for CART has shifted from cirrhosis to cancerous peritonitis, it has become necessary to deal with the clogging of the concentration filter when processing large amounts of cancerous ascites with high protein concentrations. Our technology for self-regulation function of the concentration ratio has been introduced into M-CART and other CART specialized equipment, enabling safe automatic concentration within set pressure range (constant pressure concentration). However, when treating ascites with low protein concentration, constant pressure concentration at a high concentration ratio may enhance protein leakage into the waste fluid and reduce protein recovery rate. Therefore, we devised a hybrid concentration method that combines constant pressure and constant ratio concentration, and investigated its usefulness in improving protein recovery by using simulated ascites and analyzing multicenter clinical evaluations. Methods: In the experiment, simulated ascites using substitute plasma agent (hydroxyethylated starch, HSE) was used to simulate cancerous ascites. In the clinical evaluation, 129 sessions of CART performed using M-CART were examined. Results: In the experiment, as the control pressure was increased, the waste fluid volume and HSE concentration in the waste fluid increased and the recovery rate decreased. In the analysis of clinical cases, protein recovery rate was lower in cases where constant pressure concentration was performed. These results indicate that constant-pressure concentration at a high concentration ratio in ascites with a low protein concentration risks decreasing the protein recovery rate, and that the hybrid concentration method enables concentration with a high recovery rate according to the condition of the ascites fluid.