Evaluation of the treatment volume and removal rate of Rheocarna: A novel adsorption-type blood purification device for patients with chronic limb-threatening ischemia

Correlation between bradykinin concentration and blood pressure during Rheocarna therapy: A single-center case series

INTRODUCTION

A novel LDL (low-density lipoprotein) apheresis therapeutic option, Rheocarna, has garnered attention as an alternative therapy for chronic limb-threating ischemia (CLTI). Bradykinin-mediated vasodilation is involved in the effects of LDL apheresis and a decrease in blood pressure (BP), but the changes in bradykinin concentration during Rheocarna therapy are unknown.

METHODS

The study involved patients with CLTI treated with Rheocarna at our hospital, from April 2022 to August 2023.

RESULTS

After Rheocarna therapy, skin ulcers improved in 80% of the patients. Circuit coagulation was observed in two patients with high fibrinogen levels. A decrease in BP was observed at approximately the same time when the bradykinin concentration peaked. The peak bradykinin concentration in a patient undergoing hemodialysis at the same time was considerably lower than that in the other patients.

CONCLUSION

This is the first report on the changes in bradykinin concentration under Rheocarna therapy.

Investigation of treatment volume versus circulating blood volume during Rheocarna treatment

INTRODUCTION

Rheocarna's therapeutic effect is associated with fibrinogen (Fib) and low-density lipoprotein cholesterol (LDL-C) adsorptive removal. This study aimed to retrospectively investigate the association between treatment volume (TV) and circulating blood volume (CBV) and the Fib removal rate (Fib-RR) and LDL-C-RR.

METHODS

CBV and TV/CBV, cut-off value (CO value), and area under the receiver operating characteristic (ROC) curve (AUC) were calculated. The Fib-RR and LDL-C-RR at the midterm and end of treatment were compared. The groups were further categorized into three groups with TV/CBV lower than or higher than the CO value at the midterm and end (midterm/end; Group L: lower than/lower than CO; Group L/H: lower than/higher than CO; Group H: higher than/higher than CO), and the Fib-RR and LDL-RR of each group at the midterm and end were compared.

RESULTS

ROC analysis revealed a TV of 1.480 times the BV as CO value, which showed a maximum Youden index predicting a Fib-RR of 20% (AUC: 0.828). Among the three groups, Group L and Group L/H demonstrated significantly higher Fib-RR and LDL-C-RR at the end of the study than in the midterm, while Group H exhibited no difference.

CONCLUSION

The results reveal that a treatment volume of 1.5 times the circulating blood volume is a sufficient solute removal capacity in the Rheocarna-enabled cases.