RESUMEN

Background: High blood pressure is a major risk factor for cardiac remodeling and left ventricular hypertrophy, increasing cardiovascular risk and leading to heart failure with preserved ejection fraction (HFpEF). Since renal sympathetic denervation (RDN) reduces blood pressure in the long term, we aimed to investigate the long-term effect of RDN in patients with HFpEF in the present analysis. Methods: Patients previously enrolled in a local RDN registry who underwent high-frequency RDN with the use of the Symplicity Flex® renal denervation system between 2011 and 2014 were followed up. The patients were assessed by 24-h ambulatory blood pressure measurement, transthoracic echocardiography, and laboratory tests. We used the echocardiographic and biomarker criteria of the Heart Failure Association (HFA)-PEFF (Pre-test assessment, Echocardiography and Natriuretic Peptide Score, Funkctional testing, and Final aetiology) score to identify patients with HFpEF. Results: Echocardiographic assessment was available for 70 patients at a 9-year long-term follow-up. Of these patients, 21 had HFpEF according to the HFA-PEFF score. We found a significant reduction of the HFA-PEFF score from 5.48 ± 0.51 points at baseline to 4.33 ± 1.53 points at the 9-year follow-up (P < 0.01). This decrease was due to a greater reduction in morphological and biomarker subcategories [from 1.95 ± 0.22 to 1.43 ± 0.51 points (P < 0.01) and from 1.52 ± 0.52 to 0.90 ± 0.63 points (P < 0.01), respectively] than in the functional one. Morphologically, there was a reduction in left ventricular hypertrophy and left atrial dilation. Conclusions: The present analysis suggests that RDN may lead to a regression of the extent of HFpEF beyond a reduction in blood pressure and thus possibly contribute to an improvement in prognosis. More detailed information will be provided by ongoing randomized sham-controlled trials.

RESUMEN

The US Food and Drug Administration has approved renal denervation (RDN) as a new treatment option for hypertension (HT) because it not only has antihypertensive effects but also improves the quality of blood pressure (BP) reduction. RDN is expected to be increasingly used in clinical practice in the future. This review summarizes the impact of RDN on quality of life (QOL). Although the treatment of HT aims to improve life prognosis, the use of antihypertensive agents can impair QOL because of adverse effects and lifestyle changes associated with long-term medication use. Consequently, poor adherence to antihypertensive agents is a common problem and may be the most important issue affecting patient QOL. In RDN trials in patients taking antihypertensive agents, approximately 40% of patients had poor adherence to the drugs. Poor adherence is often the cause of resistant hypertension. Therefore, RDN should be well suited to treating HT and improving QOL. Studies have shown that approximately 30% of HT patients prefer RDN to drug treatment. Patients who prefer RDN are typically male and younger and have high BP, poor adherence, and a history of adverse effects of antihypertensive agents. We hope that RDN will improve not only life prognosis but also QOL in HT patients because of its benefits for adherence. Furthermore, we expect that in the future, RDN will be used in other sympathetic nervous system-related diseases, such as heart failure, atrial fibrillation, and sleep apnea syndrome.

RESUMEN

This review provides an overview of the efficacy and safety of renal sympathetic denervation as a therapeutic approach for resistant hypertension. While the initial enthusiasm was sparked by the results of early clinical trials, it was dampened by the findings of the Symplicity HTN-3 study. However, recent advances in catheter technology and more refined patient selection criteria have yielded more promising results. Subsequent studies, such as SPYRAL HTN-OFF MED and RADIANCE II, demonstrated significant reductions in blood pressure, even in patients with mild to moderate hypertension. Despite the lack of robust data on major clinical outcomes, investigations into the time in therapeutic range for patients undergoing renal sympathetic denervation suggested potential cardiovascular benefits. Nevertheless, further research is needed to thoroughly understand the long-term impact, assess cost-effectiveness, and accurately identify which patient subgroups may derive the greatest benefits from this therapy.

Esta revisión brinda una síntesis de la eficacia y la seguridad de la denervación simpática renal como enfoque terapéutico para la hipertensión resistente. A pesar del entusiasmo inicial generado por los resultados de los primeros ensayos clínicos, la eficacia de esta terapia se vio comprometida por los hallazgos negativos del estudio Symplicity HTN-3. Sin embargo, recientes avances en la tecnología de catéteres y una refinada selección de los pacientes han proporcionado resultados más prometedores. Estudios posteriores, como SPYRAL HTN-OFF MED y RADIANCE II, demostraron reducciones significativas en la presión arterial, incluso en pacientes con hipertensión de leve a moderada. A pesar de la falta de datos sólidos sobre desenlaces clínicos importantes, las investigaciones sobre el tiempo en rango terapéutico de los pacientes sometidos a denervación simpática renal sugirieron posibles beneficios cardiovasculares. No obstante, se requiere una mayor investigación para comprender a fondo el impacto a largo plazo, evaluar la relación costo-efectividad y determinar con precisión qué subgrupos de pacientes podrían obtener los mayores beneficios de esta terapia.

Asunto(s)

RESUMEN

The denervation or activation of the sympathetic nerve in the kidney can affect renal hemodynamics. The sympathetic nervous system regulates the physiological functions of the kidneys. Stimulation of sympathetic efferent nerves affects various parameters related to renal hemodynamics, including sodium excretion, renin secretion, and renal blood flow (RBF). Hence, renal sympathetic fibers may also play an essential role in regulating systemic vascular resistance and controlling blood pressure. In the absence of renal nerves, the hemodynamics response to stimuli is negligible or absent. The effect of renal sympathetic denervation on RBF is dependent on several factors such as interspecies differences, the basic level of nerve activity in the vessels or local density of adrenergic receptor in the vascular bed. The role of renal denervation has been investigated therapeutically in hypertension and related disorders. Hence, the dynamic impact of renal nerves on RBF enables using RBF dynamic criteria as a marker for renal denervation therapy.

RESUMEN

BACKGROUND: Renal denervation (RDN) has emerged in recent years as a possible treatment for hypertension. The first sham-controlled trial showed a small magnitude and non-significant in the blood pressure (BP) lowering effect, also due to a substantial decrease of BP in sham arm. Considering this, we aimed to quantify the magnitude of BP decrease within the sham arm of Randomized Controlled Trials (RCT) with RDN in patients with hypertension. METHODS: Electronic databases were searched since inception until January 2022 for randomized sham-controlled trials which assessed the efficacy in lowering BP of the sham intervention for catheter-based RDN in adult patients with hypertension. The outcomes were change in ambulatory/office systolic and diastolic BP. RESULTS: A total of 9 RCT were included in the analysis enrolling a total of 674 patients. Sham intervention showed a decrease in all evaluated outcomes. Office systolic BP had a reduction of -5.52 mmHg [95%CI -7.91, -3.13] and office diastolic BP of -2.13 mmHg [95%CI -3.08, -1.17]. Sham procedure for RDN also showed a reduction of -3.41 mmHg [95%CI -5.08, -1.75] in ambulatory systolic BP and - 2.44 mmHg [95%CI -3.31, -1.57] in ambulatory diastolic BP. CONCLUSION: Despite recent data indicating that RDN might be an effective treatment for patients with resistant hypertension when compared to a sham intervention, our results indicate that the sham intervention for RDN also has a significant effect on lowering Office and Ambulatory (24-h) Blood Pressure in adult patients with hypertension. This highlights that BP itself might be sensitive to placebo-like effect and also brings further difficulties in establishing the BP lowering efficacy of invasive interventions due to the magnitude of the sham effect.

Asunto(s)

RESUMEN

Since the publication of the 2018 European Society of Cardiology/European Society of Hypertension (ESC/ESH) Guidelines for the Management of Arterial Hypertension, several high-quality studies, including randomised, sham-controlled trials on catheter-based renal denervation (RDN) were published, confirming both the blood pressure (BP)-lowering efficacy and safety of radiofrequency and ultrasound RDN in a broad range of patients with hypertension, including resistant hypertension. A clinical consensus document by the ESC Council on Hypertension and the European Association of Percutaneous Cardiovascular Interventions (EAPCI) on RDN in the management of hypertension was considered necessary to inform clinical practice. This expert group proposes that RDN is an adjunct treatment option in uncontrolled resistant hypertension, confirmed by ambulatory BP measurements, despite best efforts at lifestyle and pharmacological interventions. RDN may also be used in patients who are unable to tolerate antihypertensive medications in the long term. A shared decision-making process is a key feature and preferably includes a patient who is well informed on the benefits and limitations of the procedure. The decision-making process should take (i) the patient's global cardiovascular (CV) risk and/or (ii) the presence of hypertension-mediated organ damage or CV complications into account. Multidisciplinary hypertension teams involving hypertension experts and interventionalists evaluate the indication and facilitate the RDN procedure. Interventionalists require expertise in renal interventions and specific training in RDN procedures. Centres performing these procedures require the skills and resources to deal with potential complications. Future research is needed to address open questions and investigate the impact of BP-lowering with RDN on clinical outcomes and potential clinical indications beyond hypertension.

Asunto(s)

RESUMEN

Background: In randomized controlled trials (RCTs), the power is often 'reverse engineered' based on the number of participants that can realistically be achieved. An attractive alternative is planning a new trial conditional on the available evidence; a design of particular interest in RCTs that use a sham control arm (sham-RCTs). Methods: We explore the design of sham-RCTs, the role of sequential meta-analysis and  conditional planning in a systematic review of renal sympathetic denervation for patients with arterial hypertension. The main efficacy endpoint was mean change in 24-hour systolic blood pressure. We performed sequential meta-analysis to identify the time point where the null hypothesis would be rejected in a prospective scenario. Evidence-based conditional sample size calculations were performed based on fixed-effect meta-analysis. Results: In total, six sham-RCTs (981 participants) were identified. The first RCT was considerably larger (535 participants) than those subsequently published (median sample size of 80). All trial sample sizes were calculated assuming an unrealistically large intervention effect which resulted in low power when each study is considered as a stand-alone experiment. Sequential meta-analysis provided firm evidence against the null hypothesis with the synthesis of the first four trials (755 patients, cumulative mean difference -2.75 (95%CI -4.93 to -0.58) favoring the active intervention)). Conditional planning resulted in much larger sample sizes compared to those in the original trials, due to overoptimistic expected effects made by the investigators in individual trials, and potentially a time-effect association. Conclusions: Sequential meta-analysis of sham-RCTs can reach conclusive findings earlier and hence avoid exposing patients to sham-related risks. Conditional planning of new sham-RCTs poses important challenges as many surgical/minimally invasive procedures improve over time, the intervention effect is expected to increase in new studies and this violates the underlying assumptions. Unless this is accounted for, conditional planning will not improve the design of sham-RCTs.

Asunto(s)

RESUMEN

Recent trials have demonstrated the efficacy and safety of percutaneous renal sympathetic denervation (RDN) for blood pressure (BP)-lowering in patients with uncontrolled hypertension. Nevertheless, major challenges exist, such as the wide variation of BP-lowering responses following RDN (from strong response to no response) and lack of feasible and reproducible peri-procedural predictors for patient response. Both animal and human studies have demonstrated different patterns of BP responses following renal nerve stimulation (RNS), possibly related to varied regional proportions of sympathetic and parasympathetic nerve tissues along the renal arteries. Animal studies of RNS have shown that rapid electrical stimulation of the renal arteries caused renal artery vasoconstriction and increased norepinephrine secretion with a concomitant increase in BP, and the responses were attenuated after RDN. Moreover, selective RDN at sites with strong RNS-induced BP increases led to a more efficient BP-lowering effect. In human, when RNS was performed before and after RDN, blunted changes in RNS-induced BP responses were noted after RDN. The systolic BP response induced by RNS before RDN and blunted systolic BP response to RNS after RDN, at the site with maximal RNS-induced systolic BP response before RDN, both correlated with the 24-h ambulatory BP reductions 3-12 months following RDN. In summary, RNS-induced BP changes, before and after RDN, could be used to assess the immediate effect of RDN and predict BP reductions months following RDN. More comprehensive, large-scale and long term trials are needed to verify these findings.

Asunto(s)

RESUMEN

Nerve-related fluorophores generally locate in the visible or near-infrared region with shallow penetration depth and easy uptake by surrounding tissues. Prolonging the optical window promotes resolution by minimizing photoscattering and eliminating autofluorescence for NIR-II (second near infrared; 1000-1700 nm) and photoacoustic bioimaging. In addition, combination of the two could help in colocalization of targets at the 3D level. Catheter-based renal sympathetic denervation (RDN), an alternative treatment recently finishing its clinical evaluation for treating resistant hypertension, is highly dependent on experience and in urgent demand for in vivo guidance in locating the nerve over the renal artery. Here, an NIR-II and photoacoustic bioimaging system based on a dye-modified anti-tyrosine-hydroxylase antibody (TH-ICGM) to illustrate the peritoneal sympathetic nerve-related region are combined. With high resolution (0.15 mm) in NIR-II region for both absorbance (λex = 925 nm) and fluorescence (bioimaging in λem ≥ 1300 nm), TH-ICGM succeeds in providing 3D coordinates of procedure position with a precision in 0.1 mm. As the first nerve-related NIR-II immunoprobe, TH-ICGM has great clinical potential as assistance for nerve-related interventions.

Asunto(s)

RESUMEN

Cardiac resynchronization therapy (CRT) reduces the morbidity and mortality in advanced heart failure (HF) in about two-thirds of the patients. Approximately one-third of the patients do not respond to CRT. The overactivity of sympathetic nervous system is associated with advanced HF and deteriorates the hemodynamic state. We tested the hypothesis that controlling sympathetic overactivity by renal denervation (RDN) could be beneficial in nonresponders for CRT. In our HeartF-RDN study (ClinalTrials.gov. NCT02638324), RDN could not reverse the progression of HF in subjects with New York Heart Association Classification (NYHA) III-IV stage symptoms.

Asunto(s)

RESUMEN

INTRODUCTION: The aim of the present study was to assess the safety and efficacy of renal sympathetic denervation (RDN) in patients with heart failure with reduced ejection fraction (HFrEF). METHODS: We randomly assigned 50 patients with a left ventricular ejection fraction (LVEF) ≤ 35% and NYHA class ≥ II, in a 1:1 ratio, to either RDN and optimal medical therapy (OMT) or OMT alone. The primary safety endpoint was the occurrence of a combined endpoint of cardiovascular death, rehospitalisation for heart failure, and acute kidney injury at 6 months. The primary efficacy endpoint was the change in iodine-123 meta-iodobenzylguanidine (123I­MIBG) heart-to-mediastinum ratio (HMR) at 6 months. RESULTS: Mean age was 60 ± 9 years, 86% was male and mean LVEF was 33 ± 8%. At 6 months, the primary safety endpoint occurred in 8.3% vs 8.0% in the RDN and OMT groups, respectively (p = 0.97). At 6 months, the mean change in late HMR was -0.02 (95% CI: -0.08 to 0.12) in the RDN group, versus -0.02 (95% CI: -0.09 to 0.12) in the OMT group (p = 0.95) whereas the mean change in washout rate was 2.34 (95% CI: -6.35 to 1.67) in the RDN group versus -2.59 (95% CI: -1.61 to 6.79) in the OMT group (p-value 0.09). CONCLUSION: RDN with the Vessix system in patients with HFrEF was safe, but did not result in significant changes in cardiac sympathetic nerve activity at 6 months as measured using 123I­MIBG.

RESUMEN

BACKGROUND: In the wake of the controversy surrounding the SYMPLICITY HTN-3 trial and data from subsequent trials, this review aims to perform an updated and more comprehensive review of the impact of renal sympathetic denervation on cardiac arrhythmias. METHODS AND RESULTS: A systematic search was performed using the Medline, Scopus and Embase databases using the terms "Renal Denervation" AND "Arrhythmias or Atrial or Ventricular", limited to Human and English language studies within the last 10 years. This search yielded 19 relevant studies (n = 6 randomised controlled trials, n = 13 non-randomised cohort studies) which comprised 783 patients. The studies show RSD is a safe procedure, not associated with increases in complications or mortality post-procedure. Importantly, there is no evidence RSD is associated with a deterioration in renal function, even in patients with chronic kidney disease. RSD with or without adjunctive pulmonary vein isolation (PVI) is associated with improvements in freedom from atrial fibrillation (AF), premature atrial complexes (PACs), ventricular arrhythmias and other echocardiographic parameters. Significant reductions in ambulatory and office blood pressure were also observed in the majority of studies. CONCLUSION: This review provides evidence based on original research that 'second generation' RSD is safe and is associated with reductions in short-term blood pressure and AF burden. However, the authors cannot draw firm conclusions with regards to less prominent arrhythmia subtypes due to the paucity of evidence available. Large multi-centre RCTs investigating the role of RSD are necessary to comprehensively assess the efficacy of the procedure treating various arrhythmias.

Asunto(s)

RESUMEN

OBJECTIVE: To investigate the effect of renal sympathetic denervation (RDN) on blood pressure and arterial stiffness in hypertensive beagles and explore the underlying mechanism. METHODS: Sixteen beagles were randomly divided into RDN group (n=8, fed with a high-salt high-fat diet to establish models of hypertension and treated with RDN), sham-operated group (n=4, fed with a high-salt high-fat diet to induce hypertension but only examined with renal arteriography) and control group (n=4, fed with formula dog food). The changes in blood pressure, arterial stiffness, endothelial function, and sympathetic activity were compared among the 3 groups and correlation analysis was performed. RESULTS: All the animal models of hypertension were established successfully in the beagles. At 3 months after the RDN, the changes in systolic blood pressure (SBP) differed significantly among the 3 groups (P=0.006), and the reduction in SBP was significantly greater in RDN group than in the other two groups (P < 0.05). The variations of diastolic blood pressure (DBP) also differed significantly among the 3 groups (P=0.016), and DBP reduction was more obvious in RDN group than in the control group (P=0.007), but similar to that in the sham-operated group (P=0.052). The changes of resistance index (RI) after the procedure were significantly different among the 3 groups (P=0.043), and the RDN group showed a greater reduction of RI than the control group (P=0.032) and sham group (P=0.043). Serum levels of eNOS, NO and Ang Ⅱ did not differ significantly among the groups either before or after RDN (P>0.05), but serum NE level was significantly higher in RDN group than in the control groupafter successful modeling (P=0.014), but similar to that in the sham group (P=0.560). Compared with the sham operation, RDN in the hypertensive beagles resulted in a significantly greater decrease of serum NE level (P=0.032) to almost the control level (P= 0.080). The changes of RI following RDN were significantly correlated with the changes of SBP, DBP and serum levels of NO and NE (P < 0.05). CONCLUSION: RDN can significantly reduce blood pressure and improve arterial stiffness in hypertensive beagles possibly by reducing sympathetic activity and blood pressure and promoting NO synthesis.

Asunto(s)

RESUMEN

BACKGROUND: Resistant hypertension (RH) has always been a difficult problem in clinical diagnosis and treatment. At present, there is no recognized safe and effective minimally invasive treatment. CASE SUMMARY: An 80-year-old woman was admitted to hospital due to trigeminal neuralgia (TN). The patient had a history of RH for more than 10 years and her blood pressure (BP) was not well-controlled. Before the treatment for TN, we decided to perform chemical renal sympathetic denervation with ethanol in the Pain Department of our hospital. One year after the operation, she stopped taking antihypertensive drugs, and her BP was satisfactorily controlled within 4 years after surgery. CONCLUSION: Computed tomography-guided chemical renal sympathetic modulation may be a feasible method for the treatment of RH.

RESUMEN

Background: The association between the treatment efficacy and safety of high-intensity focused ultrasound (HIFU)-based renal sympathetic denervation (RDN) and the acoustic energy dose applied has not been fully studied and may provide important understanding of the mechanism that led to failure of the WAVE IV trial. The objective of this study was to externally deliver different HIFU doses to canines for RDN treatment and to investigate the optimal energy dose for HIFU-based RDN. Methods: Thirty canines were divided into five RDN groups according to dose of acoustic energy applied, and a sham control group that consisted of four canines was used for comparisons. All animals in the RDN groups underwent the RDN procedure with different acoustic energy doses, while in the sham control group, renal arteries were harvested without being subjected to acoustic energy delivery and were imaged using color Doppler flow imaging (CDFI). Blood pressure (BP) was recorded, and blood samples were collected before the RDN procedure and at 28 days after the RDN procedure. Histological examinations and measurement of renal tissue norepinephrine concentration were performed in all retrieved samples. Results: Suppression of BP was significant in the 300 W (15.17/8.33 ± 1.47/1.21 mmHg), 250 W (14.67/9.33 ± 1.21/1.37 mmHg), and 200 W (13.17/9.17 ± 2.32/1.84 mmHg) groups. Semiquantitative histological assessment of periarterial nerves around the kidney revealed that target nerves in the 300 W (9.77 ± 0.63), 250 W (9.42 ± 0.67), and 200 W (9.58 ± 0.54) groups had the highest nerve injury scores, followed by the 150 W group (5.29 ± 0.62). Furthermore, decreased renal tissue norepinephrine concentration, together with decreased expression of tyrosine hydroxylase in the 300, 250, and 200 W groups demonstrated effective sympathetic depression following sufficient acoustic energy deposition. However, the renal artery injury score in the 300 W group (0.93 ± 0.13) was significantly higher than in the other groups (p < 0.001). Conclusion: This study provides evidence that RDN effectiveness is based on the energy dose delivered and that 200-250 W is effective and safe in normal-sized canines.

RESUMEN

PURPOSE: Blood pressure (BP) reduction after renal sympathetic denervation (RDN) is highly variable. Renal nerve stimulation (RNS) can localize sympathetic nerves. The RNS trial aimed to investigate the medium-term BP-lowering effects of the use of RNS during RDN, and explore if RNS can check the completeness of the denervation. MATERIAL AND METHODS: Forty-four treatment-resistant hypertensive patients were included in the prospective, single-center RNS trial. The primary study endpoint was change in 24-h BP at 6- to 12-month follow-up after RDN. The secondary study endpoints were the acute procedural RNS-induced BP response before and after RDN; number of antihypertensive drugs at follow-up; and the correlation between the RNS-induced BP increase before versus after RDN (delta [Δ] RNS-induced BP). RESULTS: Before RDN, the RNS-induced systolic BP rise was 43(±21) mmHg, and decreased to 9(±12) mmHg after RDN (p < 0.001). Mean 24-h systolic/diastolic BP decreased from 147(±12)/82(±11) mmHg at baseline to 135(±11)/76(±10) mmHg (p < 0.001/<0.001) at follow-up (10 [6-12] months), with 1 antihypertensive drug less compared to baseline. The Δ RNS-induced BP and the 24-h BP decrease at follow-up were correlated for systolic (R = 0.44, p = 0.004) and diastolic (R = 0.48, p = 0.003) BP. Patients with ≤0 mmHg residual RNS-induced BP response after RDN had a significant lower mean 24-h systolic BP at follow-up compared to the patients with >0 mmHg residual RNS-induced BP response (126 ± 4 mmHg versus 135 ± 10 mmHg, p = 0.04). 83% of the patients with ≤0 mmHg residual RNS-induced BP response had normal 24-h BP at follow-up, compared to 33% in the patients with >0 mmHg residual RNS-induced BP response (p = 0.023). CONCLUSION: The use of RNS during RDN leads to clinically significant and sustained lowering of 24-h BP with fewer antihypertensive drugs at follow-up. RNS-induced BP changes were correlated with 24-h BP changes at follow-up. Moreover, patients with complete denervation had significant lower BP compared to the patients with incomplete denervation.

Asunto(s)

RESUMEN

Renal denervation transmits radiofrequency (RF) energy through an electrode to treat resistant hypertension (RH), applying ablation in the renal artery. Several experimental studies have shown that this treatment has been used effectively to treat RH. The aim of this paper is to investigate the effect of ablation parameters (i.e., electrode length, applied voltage, ablation time, and blood flow) on the temperature distribution using a balloon-based array electrodes system. A simplified three-dimensional model including four electrodes and a balloon was established. The balloon diameter was 3 mm and placed in a 5 mm diameter renal artery for forming intra-arterial occlusion. Four electrodes were mounted on the balloon and distributed in the same plane to mimic circumferential RF ablation. Computer simulations were conducted to investigate the thermal performances of the device by setting different electrode configurations, treatment protocols, and physiological factors. The thermal performances including the thermal distribution, maximum lesion depth, length, and area were analyzed. The lesion shape of the array RF electrodes was approximately a sphere with a 100% circumference coverage rate of the renal artery. The lesion depth and length increase with each factor except for blood velocity. Increasing the electrode length from 2 to 4 mm or 2 to 6 mm, the lesion depth increases by 1.15 mm and 0.54 mm at 60 s. The corresponding lesion length increases by 2.65 mm and 2.34 mm, respectively. The range of effective lesion depth is 1.90-4.90 mm, at a voltage of 15-30 V. But the peak temperature at the arterial outer wall exceeded 100 °C when the voltage is above 25 V. In tissue, the degree of thermal injury in the 2 mm area reached 100%, but in blood was not more than 5%. There was no significant difference at different flow conditions because the difference value in lesion depth was not exceeded 0.5 mm. The results showed that the balloon-based four electrodes system is expected to overcome the difficulty of incomplete ablation. In clinical application, 2 mm-electrode is recommended to avoid long wall damage as much as possible and control the voltage below 25 V. This treatment has little thermal injury on the blood, which means it may avoid coagulation formation. Moreover, the application of this device does not need to consider the difference in individual blood velocity.

Asunto(s)

RESUMEN

OBJECTIVE: Renal sympathetic denervation (RDN) is an alternative treatment for resistant hypertension (RH). This study aims to compare ablation effects using three radiofrequency applicators (i.e., balloon-based four electrodes, spiral and monopolar devices). METHODS: An idealized three-dimensional model of the renal artery was established using COMSOL Multiphysics to mimic radiofrequency ablation (RFA). Radiofrequency (RF) energy was delivered to the tissue at the same simulation settings, i.e., 4, 6, and 8 W for 60 s, using the three abovementioned RF applicators. The temperature distribution in the tissue was calculated using the coupled electrical-thermal-fluid finite element method. Lesion borders were defined using 50 °C isotherms. The maximum lesion depth, width, area, and circumferential coverage rate were compared among the three applicators at a blood flow of 0.4 m/s. Monopolar RF ablations in a renal artery phantom model were performed to validate the reliability of the simulation method. RESULTS: The balloon-based system yields greater lesion depths and widths compared with spiral and monopolar denervation under the same power. The range of maximum lesion depth is 1.58-3.11 mm for balloon-based RDN, 0.90-1.81 mm for spiral RDN and 1.12-2.38 mm for monopolar RDN, at a power of 4-8 W. The corresponding ranges of maximum lesion width are 2.22-5.73, 1.48-3.54, and 1.93-5.31 mm, respectively, and the circumferential coverage rates of the renal artery are 41.43%-91.99%, 31.71%-66.23%, and 9.55%-23.06%, respectively. The average velocity after balloon-based, spiral, and monopolar RDN increases by 3, 5, and 1 cm/s, respectively. The validation of the computer model offered prediction errors are <5% in terms of temperature at different locations (i.e., 2, 4, and 8 mm). CONCLUSIONS: In terms of lesion size, balloon-based RDN appears to be the best option for the treatment of RH. However, the change in flow velocity in the arterial flow field suggests that its hemodynamic changes must be prioritized for investigating its safety. Although spiral catheter ablation yields the smallest lesion size and a significant change in flow velocity in the flow field, its coverage rate is larger than that of monopolar RDN; compared with balloon-based RDN, it did not obstruct most of the blood flow.

Asunto(s)

RESUMEN

INTRODUCTION: Renal sympathetic denervation (RSDN) is an alternate management approach for refractory ventricular arrhythmias (VAs). We aimed to perform a systematic review of clinical outcomes on the impact of RSDN on refractory VA patients. METHODS: A systematic search without language restriction, using PubMed, EMBASE, SCOPUS, Google Scholar, and ClinicalTrials.gov from inception to August 18, 2020, was performed for the studies that reported outcomes in patients who underwent RSDN for VA. The outcomes studied were-(1) recurrent VA; and (2) all-cause mortality. RESULTS: Five studies (from 2014 to 2018) with a total of 51 VA patients met study inclusion criteria. The mean age was 61.92 ± 11.76 years, and 78.4% were men. The pooled incidence of short-term (3 months or less) and long-term (more than 3 months) VA recurrence was 63.85% (95% CI 16.75 to 99.32) and 10.52% (95% CI 0.14 to 28.75), respectively. When stratified by the number of VA episodes, there was a significant reduction in mean VA episodes (SMD -3.79, 95% CI -6.59 to -0.98, p < .01), ICD shocks (SMD -1.71, 95% CI -3.0 to -0.42, p < .01) and anti-tachycardia pacing (SMD -1.21, 95% CI -1.98 to -0.44, p < .01) following RSDN denervation. The pooled incidence of all-cause mortality after RSDN was 10.16% (95% CI 1.08 to 24.12). There were no major vascular complications, one minor vascular complication-small non-flow limiting renal artery dissection (no intervention needed). CONCLUSION: RSDN appears to be a safe and effective treatment strategy in patients with prior failed antiarrhythmic drugs and catheter ablation for recurrent ventricular arrhythmia and electrical storm.

Asunto(s)

RESUMEN

BACKGROUND: No methods exist for confirming nerve ablation in catheter-based renal sympathetic denervation (RDN). METHODS: We investigated the feasibility of using intravascular ultrasound (IVUS) to locate nerves and observe nerve integrity changes during RDN in a pig. To confirm our observations, we used post-RDN histological sections matched anatomically to the IVUS images. RESULTS: IVUS revealed multiple hypoechoic structures along the renal artery, whose locations matched those of nerves in the histological sections. Nerves clustered near the junction between the renal artery and vein. Histology confirmed necrosis of nerve bundles at RDN ablation sites, but no changes in echogenicity were observed using IVUS. CONCLUSIONS: Although IVUS cannot currently be used to confirm ablation during RDN, it clearly reveals some clusters of renal sympathetic nerves. It remains to be demonstrated how IVUS can guide RDN devices and potentially improve ablation success.