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Purpose: Residual renal function (RRF) is associated with improved clinical outcomes but it characteristically declines upon hemodialysis (HD) initiation. Although the reason for this is not clear, recurrent renal ischemic insults may be responsible. The purpose of this work was to assess the effects of HD on renal hemodynamics using CT perfusion (CTP) imaging and to explore dialysate cooling as a protective intervention against intradialytic circulatory stress.
Methods: 29 patients (on HD ≥3 months, urine output <250 mL/day) provided informed consent. 14 patients underwent standard (36.5°C dialysate temperature) HD while 15 patients were randomized to receive standard or cooled (35.0°C) HD first in a 2-visit crossover study. Free-breathing CTP imaging was performed before, during and after HD (2 min/scan) on a 256-slice scanner (GE Healthcare) without interrupting HD. Non-rigid registration and ASIR were used to reduce breathing motion and image noise, respectively. Renal perfusion maps were generated from the processed images.
Results: Average baseline renal perfusion was markedly reduced compared to normal (33.2 vs. >200 mL/min/100g) and was related to time on dialysis (r=-0.35, p<0.01). Renal perfusion dropped approximately 20% (p<0.01) and 10% (NS) during standard and cooled HD, respectively (drops were not different from one another). Decreased renal perfusion was observed in 65% and 50% of kidneys during standard and cooled HD, respectively (not significantly different).
Conclusion: This is the first study to demonstrate that HD-induced circulatory stress is linked to a significant decline in renal perfusion and that cooling trended towards mitigating these effects. Recurrent HD-induced renal ischemia resulting in cumulative kidney injury lays the ground work towards pathophysiologically explaining the previously observed relationship between time spent on dialysis and declining RRF. Future work should focus on patients with higher RRF and to longitudinally follow incident HD patients with respect to declining RRF.
Funding Support, Disclosures, and Conflict of Interest: TYL licenses the CT Perfusion software to GE Healthcare. The other authors of this article have no other relevant conflicts of interest to disclose.
Not Applicable / None Entered.
Not Applicable / None Entered.