Laparoscopic-based perivascular unilateral renal sympathetic nerve denervation for treating resistant hypertension: a case report

CT-guided ozone-mediated lumbar-renal sympathetic denervation for resistant hypertension treatment: A pilot single-arm clinical trial

BACKGROUND

Renal sympathetic denervation (RDN) reduces blood pressure (BP).

METHODS

This single-arm open-label study enrolled patients with resistant hypertension (RH) and treat them by CT-guided ozone mediated lumbar-renal sympathetic denervation (L-RDN). The primary endpoint was to assess the changes of BP over 24-h ambulatory BP monitoring (ABPM) and to evaluate the anti-hypertensive medication burden (AHMB) at 3-month follow-up. This study was registered in Chictr.org.cn (ChiCTR2300071375).

RESULTS

17 patients (mean age 65.12 ± 10.77 years) with AHMB of 4.12 ± 1.11 were enrolled. After the procedure, 7 patients (46.7 %) matched the criteria for antihypertensive medication reduction. The AHMB decreased to 3.87 ± 0.96 for the whole objectives and from 3.87 ± 0.96 to 3.55 ± 0.78 for patients with normal baseline renal function. On top of the lessened AHMB, L-RDN further reduced morning systolic BP (SBP) by -8.6 ± 4.0 mmHg (p = 0.034) and diastolic BP (DBP) by -4.6 ± 2.1 mmHg (p = 0.032) for all participants and morning SBP by -13.2 ± 3.6 mmHg (p < 0.001), morning DBP by -6.2 ± 2.4 mmHg (p = 0.011) and daytime SBP by -4.1 ± 1.6 mmHg (p = 0.009) for those with normal baseline renal function at 3-month of follow-up. No adverse events were reported intra- and post operation.

CONCLUSIONS

CT-guided ozone-mediated L-RDN might be an innovative approach of RDN for treating RH. Confirmatory studies are warranted.

Effect of extensive artery isolation during robotic-assisted partial nephrectomy on blood pressure of patients with poorly controlled hypertension: a preliminary study

PURPOSE

To investigate whether extensive renal artery isolation during robotic-assisted partial nephrectomy (RAPN) for renal cell carcinoma (RCC) affects blood pressure (BP) of patients with poorly controlled hypertension.

METHODS

We included 60 patients diagnosed with poorly controlled hypertension who underwent RAPN by an experienced surgeon. The renal artery of the treated kidney was sufficiently isolated. Systolic BP (SBP), diastolic BP (DBP) and antihypertensive medication information were obtained at baseline and 3- and 6-month follow-up after surgery. Primary endpoints were changes in BP, and medications. Predictors of SBP reduction at 3 months were assessed by multivariable logistic regression.

RESULTS

All 60 RAPN procedures were successful, with no major intra- or postoperative complications. Mean SBP and DBP decreased significantly at 3 months after surgery (SBP, -7.8 ± 6.3 mmHg, P < 0.001; DBP, -4.2 ± 6.4 mmHg, P = 0.01). SBP and DBP did not differ between 3- and 6-month follow-up. The mean number of BP medications prescribed was lower at 3 months than baseline (1.7 ± 1.0 vs 2.1 ± 1.0, P = 0.016). The only significant predictor of SBP reduction at 3 months was baseline SBP.

CONCLUSIONS

Renal denervation with extensive renal artery isolation during RAPN may improve BP control among patients with poorly controlled hypertension in short term.

Circular Radio-Frequency Electrode With MEMS Temperature Sensors for Laparoscopic Renal Sympathetic Denervation

OBJECTIVE

Laparoscopic renal denervation (LRDN) ablates sympathetic nerves on the outer wall of a renal artery to treat autonomic nervous system disorders such as hypertension and arrhythmia. Here, we developed a new circular radio frequency (RF) electrode for LRDN using micro-electro-mechanical systems (MEMS) technology.

METHODS

The electrode consists of a parallel bipolar MEMS electrode, two MEMS thermocouples, and a shape-memory alloy (SMA) substrate. The electrode is automatically wrapped and unwrapped under actuation controlled by the heat generated by RF energy on the electrode-tissue interface. The electrode was designed through a computational simulation analysis, and its actuation and temperature-sensing performance were tested in laboratory experiments and a porcine animal study.

RESULTS

In an in-vivo study of porcine renal arteries, the electrode could automatically wrap and unwrap around an artery during LRDN. The bipolar MEMS electrode required 13 V_rms for heat generation up to 60°C, while the two MEMS thermocouples reliably measured the temperature without noise signals (a temperature coefficient of 38.3 or 38.5 µV/°C and an accuracy of ±0.44 or ±0.49°C). As revealed in a histological analysis using hematoxylin and eosin staining and Masson's trichrome staining, the renal artery was intact after LRDN.

CONCLUSION

The circular RF electrode improves the safety of LRDN by reliably measuring the electrode temperature of the electrode during RDN and enhances the effectiveness of LRDN by reducing the complicated manipulations of the surgical instrument.

SIGNIFICANCE

The developed circular RF electrode will pave the way for LRDN treatment of autonomic nervous system disorders.

Laparoscopic Ablation System for Complete Circumferential Renal Sympathetic Denervation

GOAL

The catheter-based renal denervation (RDN) showed promising results for patients in lowering BP, but there were also many non-responders. One of the possible reasons was the incomplete neural ablation due to the ablation of renal nerves at random sites resulting in asymmetric innervation patterns along the renal artery.

METHODS

We developed a laparoscopic ablation system that is optimized for complete RDN regardless of renal arterial innervation and size. To demonstrate its effectiveness, we evaluated the system using computational simulation and 28-day survival model using pigs.

RESULTS

The ablations were focused around the tunica externa, and the ablation patterns could be predicted numerically during RDN treatment. In the animal study, the mean reduction of systolic BP and diastolic BP in the bilateral main renal arteries was 22.8 mmHg and 14.4 mmHg (P<0.001), respectively. The respond to immunostaining targeting tyrosine hydroxylase was significantly reduced at treatment site (108.2 ± 7.5 (control) vs. 63.4 ± 8.7 (treatment), P<0.001), and an increased degree of sympathetic signals interruption to kidneys was associated with the efficacy of RDN.

CONCLUSION

The laparoscopic ablation system achieved complete circumferential RDN at the treatment site and could numerically predict the ablation patterns.

SIGNIFICANCE

These findings clearly suggest that the proposed system can significantly improve the RDN effectiveness by reducing the variation to the percentage of injured nerves and open up a new opportunity to treat uncontrolled hypertension.

Blood Pressure Modulation With Low-Intensity Focused Ultrasound Stimulation to the Vagus Nerve: A Pilot Animal Study

Objective

For hypertensive individuals, their blood pressure (BP) is often managed by taking medications. However, antihypertensive drugs might cause adverse effects such as congestive heart failure and are ineffective in significant numbers of the hypertensive population. As an alternative method for hypertension management, non-drug devices-based neuromodulation approaches such as functional electrical stimulation (FES) have been proposed. The FES approach requires the implantation of a stimulator into the body. One recently emerging technique, called low-intensity focused ultrasound stimulation (FUS), has been proposed to non-invasively modulate neural activities. In this pilot study, the feasibility of adopting low-intensity FUS neuromodulation for BP regulation was investigated using animal models.

Methods

A FUS system was developed for BP modulation in rabbits. For each rabbit, the low-intensity FUS with different acoustic intensities was used to stimulate its exposed left vagus nerve, and the BP waveform was synchronously recorded in its right common carotid artery. The effects of the different FUS intensities on systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MAP), and heart rate (HR) were extensively examined from the BP recordings.

Results

The results demonstrated that the proposed FUS method could successfully induce changes in SBP, DBP, MAP, and HR values. When increasing acoustic intensities, the values of SBP, DBP, and MAP would tend to decrease more substantially.

Conclusion

The findings of this study suggested that BP could be modulated through the FUS, which might provide a new way for non-invasive and non-drug management of hypertension.