Validation of a Novel Renal Denervation System With Cryoablation

Figures

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  Figure 1. Schematic Diagram of the Cryo-RDN System (A) Illustration of the Cryo-RDN catheter in the renal artery (lateral view, anterior view, and sectional axonometric view of the balloon during cryoablation). (B) Temperature change curve of the balloon surface and 3 mm outside the balloon after the start of cryoablation. The balloon consists of a double-coiled high-efficiency freezing and thawing element. During cryoablation, liquid nitrogen at ultralow temperature flows inside the coil freezing element and absorbs heat from surrounding tissues. Cryo-RDN = renal denervation with cryoablation.

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  Figure 2. Nerve and Tissue Damage Around the Renal Artery (A) Images of peripheral renal artery injury with hematoxylin & eosin, Masson, and TH staining at different time points. Successful Cryo-RDN was verified by persistent nerve fibrosis and atrophy for up to 180 days. (B) Decrease in TH staining intensity suggesting a decrease in sympathetic activity, scored on a scale from 0 to 3: 0 means no reaction, 1 means patchy/very weak reaction, 2 means weak to moderate reaction, and 3 means strong reaction. The minimum score that represents the most serious functional damage was adopted for each section. (C) Semiquantitative analysis of maximum ablation depth at different times. The maximum ablation depth stabilized at a high level for 180 days. (D) Semiquantitative analysis of maximum ablation circumference at different times. The maximum ablation circumference stabilized at a high level for 180 days. Values are expressed as the mean ± SD by repeated-measures analysis of variance (n = 8 for the control group, n = 10 for the CR-7d group, n = 10 for the CR-14d group, n = 10 for the CR-28d group, n = 10 for the CR-90d group, and n = 10 for the CR-180d group). ∗P < 0.05. TH = tyrosine…

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  Figure 3. Renal and Serum NE Concentration at Different Times (A) NE concentration in the renal cortex at different times after Cryo-RDN. (B) NE concentration in serum at different times after Cryo-RDN. Values are expressed as the mean ± SD by repeated-measures of analysis of variance (n = 4 for the control group, n = 5 for the CR-7d group, n = 5 for the CR-14d group, n = 5 for the CR-28d group, n = 5 for the CR-90d group, and n = 5 for the CR-180d group). ∗P < 0.05. NE = norepinephrine; other abbreviations as in Figures 1 and 2.

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  Figure 4. Representative Renal Angiograms of Patients Who Underwent Cryo-RDN at Different Times (A) Preprocedure; (B) balloon inflation; (C) cryoablation; (D) postcryoablation; and (E) at the 6-month follow-up. Abbreviation as in Figure 1.

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  Figure 5. BP at Different Times After Cryo-RDN (A) Average 24-hour ABPM at baseline and 6 months after Cryo-RDN. (B) Average reduction in 24-hour ABPM at baseline and 6 months after Cryo-RDN. (C) Average OBP at baseline and 6 months after Cryo-RDN. (D) Average reduction in OBP at baseline and 6 months after Cryo-RDN. Values are expressed as the mean ± SD (n = 6). 24-hour ABPM = 24-hour ambulatory blood pressure monitoring; BP = blood pressure; DBP = diastolic blood pressure; OBP = office blood pressure; SBP = systolic blood pressure; other abbreviations as in Figure 1 and 2.

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  Figure 6. Changes in the BP Values of Individual Patients at the 6-Month Follow-Up Compared With Baseline Abbreviations as in Figure 5.