ABSTRACT
Objective To explore the feasibility of the catheter-based renal sympathetic denervation (RDN) guided by monitoring fractional flow reserve (FFR) with pressure guide wire. Methods Eleven minipigs were allocated into RDN group (n=8) and sham operation group (n=3). Before ablation, the angiography of bilateral renal arteries was conducted. Ablation catheter and FFR pressure guide wire were implanted in the renal arteries guided by 7F guided catheter. Then renal arteries were observed by X-ray. The FFR value (renal artery pressure/aortic pressure) was monitored by electric stimulation (20 Hz). When the FFR value had significant change, the target was to be ablated (50°C, 10 W, 60 s). The ablation was considered effective once there was no change of the above indicators after a second stimulation immediately following ablation. Results Renal artery ablation was successfully completed in all the 8 pigs of RDN group. FFR values were monitored before and after ablation, and the results showed that the FFR values were significantly decreased upon stimulation before RDN (0.73±0.07 vs 0.98±0.02, P<0.01), and the FFR values were almost unchanged immediately after ablation (0.97±0.03 vs 0.95±0.02,P=0.25), which was not observed in the sham operation group. Conclusion There is significant difference in the FFR values of the target following stimulation before and after RDN. The FFR pressure guide wire-mediated target ablation may become a new operation mode, with its effectiveness and mechanism needed to be further verified.
ABSTRACT
Objective To explore the renal artery diameter immediately after the renal sympathetic denervation (RDN) in patients with resistant hypertension. Methods Patients with resistant hypertension were enrolled in this study, and all patients were measured and recorded for the renal artery diameter values using the quantitative coronary angiography (QCA) before and immediately after the RDN. All the ablation parameters including starting impedance, terminal impedance, ablation power, and ablation point were recorded. Ambulatory blood pressure (BP) measurement was performed at the baseline and 6 months after RDN. Results A total of 12 patients with resistant hypertension were finally enrolled in this study. The mean ambulatory BP of the patients was (185±15)/(99±9) mmHg (1 mmHg=0.133 kPa) at admission, which was decreased by 31/15 mmHg in 6 months after RDN, showing significant difference compared with before RDN (P 0.05). No peripheral vascular complications occurred in these patients. Conclusion RDN can significantly reduce the ambulatory BP in patients with resistant hypertension, and expand the renal artery diameter immediately. The degree of renal artery diameter dilation is positively correlated with the ablation impedance decrease, but it can not predict the long-term BP in patients.