The JuxtaFlow® Renal Assist Device: A Novel Potentially Renoprotective Technology Associated with Reduced Low Urine Oxygen Burden in a Swine CPB Model
SCA Annual Meeting
Poster Presentation
Introduction
- The JuxtaFlow Renal Assist Device (JF-RAD) delivers mild negative pressure to the renal pelvises through ureteral catheters connected trans-urethrally to a pump.
- JF-RAD augments GFR, diuresis, and natriuresis in volume-overload patients with cardiorenal syndrome, but its effects on acute kidney injury (AKI) are unclear.
- AKI is a common complication of cardiac surgery, associated with low urine oxygen (puO₂) levels, potentially related to renal medullary hypoxia.
- We assessed potential renoprotection from continuous bilateral JF-RAD negative pressure treatment (Tx) in a mock cardiac surgery swine CPB model, using low puO₂ as an AKI early biomarker.
Methods
- IACUC approved — nine 50–65 kg female pigs, general endotracheal anesthesia, arterial line monitoring
- Bilateral JF-RAD catheter placement (cystoscopic): −15 mmHg (Tx) vs. no negative pressure (control)
- Periop periods: baseline (120 min) → CPB with heparin, left thoracotomy, ~120 min (incl. Xclamp & cardioplegia) → postCPB (120 min)
- Continuous q60sec bilateral puO₂ measurements via JF-RAD catheters
- Low puO₂ thresholds: <40 mmHg and <35 mmHg — expressed as degree-duration AKI early biomarkers (mmHg·min); p < 0.05 considered significant
Device Overview
Figure 1 — JF-RAD Schematic
JuxtaFlow® Renal Assist Device with bilateral ureteral catheters (coiled end) connected trans-urethrally to a negative-pressure pump targeting the renal pelvises
Figure 2 — Data Collection Protocol
Standardized per-animal collection across periop periods: standard vitals, CPB flow, hematocrit, electrolytes, ABG, creatinine clearance, urine output (JF-RAD + Foley), urinalysis, serum/urine IL-6, and q60sec puO₂
Primary Finding — Low puO₂ Burden (< 40 mmHg)
Figure 3: Burden of low urine oxygen levels (<40 mmHg), an AKI early biomarker, was significantly lower in JF-RAD–treated animals (−15 mmHg). Reanalysis including the excluded Tx animal further strengthened the primary finding (p = 0.002).
30 min
Avg. low puO₂ episode duration — Tx group
57 min
Avg. low puO₂ episode duration — Control group
Key Results
- 9 pigs completed protocol (Tx n=5, Control n=4); 1 Tx animal excluded (puO₂ started 80 min late due to technical difficulties)
- Standard measures were similar between groups; no left/right kidney puO₂ differences
- Trends toward improved renal function in Tx group: ↑ urine output, creatinine clearance, sodium excretion
- Each group had 9 low puO₂ episodes, but Tx episodes were considerably shorter (avg. 30 vs. 57 min), resulting in significantly reduced low puO₂ burden
- Episodes were most frequent in the postCPB period and were both unilateral and bilateral
- No evidence of important hematuria following catheter placement + heparin anticoagulation + CPB
- Similar findings observed at the <35 mmHg threshold analysis
Conclusions
JF-RAD negative pressure treatment significantly reduced low puO₂ burden — a putative AKI early biomarker — in a mock cardiac surgery swine CPB model.
In this small sample, catheter placement followed by heparin anticoagulation and CPB was not associated with important hematuria and did not negatively affect renal function.
Future Directions
These intriguing findings suggest JF-RAD negative pressure treatment may have renoprotective potential and support further investigation in the context of cardiac surgery with CPB, particularly for patients with high AKI risk.
References
1. Rao VS et al. Am J Physiol Regul Integr Comp Physiol 2021; 321:R588–94
2. Asher J et al. PO199, 2020 ASN Annual Meeting
3. Stafford-Smith M. Anesthesiology 2021; 135:380–1