Complication Of Radiofrequency Ablation Research Articles

Complications related to radiofrequency ablation of lung tumors: CT findings and review.

Radiofrequency ablation is a treatment option for primary and secondary lung tumors, particularly in non-surgical patients. Although it is considered a safe and effective procedure, various complications can occur. Most of these adverse events are self-limiting and can be treated conservatively; however, some may be severe and require intervention. Radiologists play a pivotal role in the diagnosis and follow-up of these conditions, aiding in their early identification and management in clinical practice. They must be familiar with the expected and unexpected imaging post-procedure features. This article reviews the main complications of radiofrequency ablation of lung tumors and their associated CT findings.

Progress of intraosseous basivertebral nerve ablation for symptomatic Modic alterations

Chronic lumbar and back pain caused by degenerative vertebral endplates presents a challenging issue for patients and clinicians. As a new minimally invasive spinal treatment method, radiofrequency ablation of vertebral basal nerve in bone can denature the corresponding vertebral basal nerve through radiofrequency ablation of degenerative vertebral endplate. It blocks the nociceptive signal transmission of the vertebral base nerve, thereby alleviating the symptoms of low back pain caused by the degenerative vertebral endplate. At present, many foreign articles have reported the operation principle, operation method, clinical efficacy and related complications of radiofrequency ablation of the vertebral basal nerve. The main purpose of this paper is to conduct a comprehensive analysis of the current relevant research, and provide a reference for the follow-up clinical research.

Strategies to reduce rates of severe endothermal heat-induced thrombosis following radiofrequency ablation

ObjectiveEndothermal heat-induced thrombosis (EHIT) is a potential complication of radiofrequency ablation (RFA). Data on effective prophylaxis of EHIT are limited. In 2018, a high-volume, single institution implemented strategies to decrease the incidence of EHIT, including a single periprocedural prophylactic dose of low-molecular-weight heparin to patients with a great saphenous vein (GSV) diameter of ≥8 mm or saphenofemoral junction (SFJ) diameter of ≥10 mm and limiting treatment to one vein per procedure. The size threshold was derived from existing literature. The study objective was to evaluate the effects of these institutional changes on thrombotic complication rates after RFA. MethodsA retrospective cohort control study was conducted using the Vascular Quality Initiative database. Data were collected for patients who underwent RFA with a GSV diameter of ≥8 mm or SFJ diameter of ≥10 mm from January 2015 to July 2022. The clinical end points were thrombotic complications (ie, thrombophlebitis, EHIT, deep vein thrombosis) and bleeding complications. Patient demographic and procedural variables were included in the analysis, and significant variables after univariable logistic regression were included in a multivariable logistic regression. ResultsAfter the policy change, the overall vein center EHIT rate decreased from 2.6% to 1.5%, with a trend toward significance (P = .096). The inclusion criterion of a GSV diameter of ≥8 mm or an SFJ diameter of ≥10 mm yielded 845 patients, of whom 298 were treated before the policy change and 547 after. There was a significant reduction in the rate of EHIT classified as class ≥III (2.34 vs 0.366; P = .020) after the institutional changes. Treatment of two or more veins and an increased vein diameter were associated with an increased risk of EHIT (P = .049 and P < .001, respectively). No significant association was found between periprocedural anticoagulation and all-cause thrombotic complications or EHIT (P = .563 and P = .885, respectively). ConclusionsThe institutional policy changes have led to lower rates of EHIT, with a reduction in severe EHIT rates in patients with an ≥8-mm diameter GSV or a ≥10-mm diameter SFJ treated with RFA. Of the changes implemented, restricting treatment to one vein was associated with a reduction in severe EHIT. No association was found with periprocedural low-molecular-weight heparin, although a type 2 error might have occurred. Alternative strategies to prevent thrombotic complications should be explored, such as increasing the dosage and duration of periprocedural anticoagulation, antiplatelet use, and nonpharmacologic strategies.

Successful management of an atrio-esophageal fistula after atrial fibrillation ablation: a case report.

Atrio-esophageal fistula is a rare but still a catastrophic complication of radiofrequency ablation of atrial fibrillation. We report a successful case of atrio-esophageal fistula with right posterolateral thoracotomy and right femoral cannulation of cardiopulmonary bypass. A 67-year-old man underwent radiofrequency ablation for atrial fibrillation. Nineteen days later, he developed cerebral infarction, and computed tomography showed air in the left atrium. He was transferred to our hospital for surgery. The upper body was placed in the left lateral decubitus position, and the lower body was placed in the left hemilateral decubitus position. The surgical approach was a right posterolateral thoracotomy in the 5th intercostal space. At first, the esophagus was transected at the diaphragm and tracheal carina levels. Then, an arterial line was inserted into the right common femoral artery and venous line into the right common femoral vein. Three U-shaped sutures of 3-0 polypropylene were placed to stop bleeding from the atrium. The esophagus was removed while snaring the 3-0 polypropylene sutures. There were two holes in the esophagus. Four drains were placed to clean the repaired site. After chest closure, the patient was placed supine. Cervical esophagostomy and enterostomy were performed. Gastric tube reconstruction via the retrosternal route was performed on postoperative day 28, and the patient was transferred to another hospital for rehabilitation on postoperative day 99. It is important to thoroughly discuss with esophageal surgeon how to reach the heart and esophagus, and how to reconstruct the esophagus later.

Risk Factors for Hospitalization Duration Longer Than 24 Hours Following Percutaneous Radiofrequency Ablation of Liver Tumours.

Prior studies have described complications of radiofrequency ablation (RFA) of liver tumours. The aim of this study was to identify risk factors for hospitalization duration longer than 24 hours following RFA of liver tumours. This retrospective, single-centre study included patients with liver tumours undergoing RFA between October 2017 and July 2020. Medical records were reviewed to collect patient, tumours, and procedure characteristics for each RFA session. The association between potential risk factors and duration of hospitalization (less than or more than 24 hours) was analyzed using univariate and multivariate logistic regressions. Our study included 291 patients (mean age: 65.2 ± 11.2 [standard deviation]; 201 men) undergoing 324 RFA sessions. Sixty-eight sessions (21.0%) resulted in hospitalization of more than 24 hours. Multivariate analysis identified each additional needle insertion per session (OR 1.4; 95% CI [1.1-1.9]; P = .02), RFA performed in segment V (OR 2.8; 95% CI [1.4-5.7]; P = .004), and use of artificial pneumothorax (OR 14.5; 95% CI [1.4-146.0]; P = .02) as potential risk factors. A history of hepatic encephalopathy (OR 2.6; 95% CI [1.1-6.0]; P = .03) was only significant in univariate analysis. Post-hoc, subgroup analysis of patients with hepatocellular carcinoma (69.8%) did not identify other risk factors. Risk factors for a hospitalization duration longer than 24 hours include a higher number of needle insertions per session, radiofrequency ablation in segment V, and use of an artificial pneumothorax.

射频消融治疗巨大肝血管瘤的并发症相关研究进展

射频消融治疗巨大肝血管瘤的并发症相关研究进展

Heme-Inducing Endothelial Pyroptosis Plays a Key Role in Radiofrequency Ablation of Hepatic Hemangioma Leading to Systemic Inflammatory Response Syndrome.

Systemic inflammatory response syndrome (SIRS) is a common complication of radiofrequency ablation (RFA) for hepatic hemangiomas. RFA can cause hemolytic reactions during hepatic hemangioma ablation. However, the mechanisms underlying RFA-induced SIRS remain unclear. We established an orthotopic liver hemangioma model and performed radiofrequency ablation. The levels of interleukin (IL)-1β and IL-18 and the production of ROS were measured. The wet-to-dry lung ratio, inflammation score, and in vivo endothelial cell permeability were examined. GSDMD-/- mice were used to investigate the effect of heme-inducing SIRS. RNA sequencing (RNA-seq) was performed to identify the main pathways underlying heme-induced SIRS. Western blotting and immunoprecipitation were used to determine the changes and interactions of associated proteins. The levels of heme, IL-1β, and IL-18 were significantly increased after RFA. The wet-to-dry lung ratio increased in hepatic hemangiomas after RFA, indicating that SIRS occurred. Heme induced increased levels of IL-1β and IL-18, cell death, wet-to-dry lung radio, and inflammation score in vitro and in vivo, indicating that heme induced SIRS and pyroptosis. Furthermore, GSDMD participates in heme-induced SIRS in mice, and GSDMD deletion in mice reverses the effect of heme. Heme regulates NLRP3 activation through the NOX4/ROS/TXNIP-TRX pathway, and an N-acetyl-L-cysteine (NAC) or NOX4 inhibitor (GLX351322) reverses heme-induced SIRS. Our findings suggest that heme induces endothelial cell pyroptosis and SIRS in mice and decreasing heme levels and ROS scavengers may prevent SIRS in hepatic hemangioma after RFA.

Fatal Hemoptysis Secondary to Severe Pulmonary Veins Stenosis and Fibrosing Mediastinitis following Radiofrequency Ablation for Atrial Fibrillation: A Case Report and Review of the Literature

Fatal hemoptysis secondary to severe pulmonary veins stenosis and fibrosing mediastinitis is an exceptional late complication of radiofrequency ablation for atrial fibrillation. We report the case of a 53-year-old male with a history of atrial fibrillation treated by radiofrequency ablation and admitted in our center 6 months after the procedure because of aggravating dyspnea and fatigability. Transthoracic echocardiography showed moderate dilation of right heart cavities, severe pulmonary hypertension and a turbulent flow in superior pulmonary veins. The cardiologist suspected pulmonary vein(s) stenosis and so cardiac computed tomography (CT) angiography was performed, with findings of severe stenosis of the right superior, right inferior and left inferior pulmonary veins, near-occlusion of the left superior pulmonary vein and the vein draining the apical segment of the right lower lobe. The CT scan also revealed soft tissue attenuation of the mediastinum posterior to the left atrium suggesting fibrosing mediastinitis together with parenchymal findings consistent with pulmonary veno-oclusive disease and an area of hemorrhagic infarction. Fatal hemoptysis occurred 3 days later, before treatment was attempted. In conclusion, severe pulmonary vein stenosis and fibrosing mediastinitis are rare but devastating complications of radiofrequency ablation. Prevention and early diagnosis are the key elements as these entities are potentially life-threatening.

Machine learning-based risk models for procedural complications of radiofrequency ablation for atrial fibrillation

BackgroundRadiofrequency ablation (RFA) for atrial fibrillation (AF) is associated with a risk of complications. This study aimed to develop and validate risk models for predicting complications after radiofrequency ablation of atrial fibrillation patients.MethodsThis retrospective cohort study included 3365 procedures on 3187 patients with atrial fibrillation at a single medical center from 2018 to 2021. The outcome was the occurrence of postoperative procedural complications during hospitalization. Logistic regression, decision tree, random forest, gradient boosting machine, and extreme gradient boosting were used to develop risk models for any postoperative complications, cardiac effusion/tamponade, and hemorrhage, respectively. Patients’ demographic characteristics, medical history, signs, symptoms at presentation, electrocardiographic features, procedural characteristics, laboratory values, and postoperative complications were collected from the medical record. The prediction results were evaluated by performance metrics (i.e., the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, F score, and Brier score) with repeated fivefold cross-validation.ResultsOf the 3365 RFA procedures, there were 62 procedural complications with a rate of 1.84% in the entire cohort. The most common complications were cardiac effusion/tamponade (28 cases, 0.83%), and hemorrhage (21 cases, 0.80%). There was no procedure-related mortality. The machine learning algorithms of random forest (RF) outperformed other models for any complication (AUC 0.721 vs 0.627 to 0.707), and hemorrhage (AUC 0.839 vs 0.649 to 0.794). The extreme gradient boosting (XGBoost) model outperformed other models for cardiac effusion/tamponade (AUC 0.696 vs 0.606 to 0.662).ConclusionsThe developed risk models using machine learning algorithms showed good performance in predicting complications after RFA of AF patients. These models help identify patients at high risk of complications and guiding clinical decision-making.

Radiofrequency ablation of lung metastases of colorectal cancer: could early radiomics analysis of the ablation zone help detect local tumor progression?

To determine whether radiomics data can predict local tumor progression (LTP) following radiofrequency ablation (RFA) of colorectal cancer (CRC) lung metastases on the first revaluation chest CT. This case-control single-center retrospective study included 95 distinct lung metastases treated by RFA (in 39 patients, median age: 63.1 years) with a contrast-enhanced CT-scan performed 3 months after RFA. Forty-eight radiomics features (RFs) were extracted from the 3D-segmentation of the ablation zone. Several supervised machine-learning algorithms were trained in 10-fold cross-validation on reproducible RFs to predict LTP, with/without denoising CT-scans. An unsupervised classification based on reproducible RFs was built with k-means algorithm. There were 20/95 (26.7%) relapses within a median delay of 10 months. The best model was a stepwise logistic regression on raw CT-scans. Its cross-validated performances were: AUROC = 0.72 (0.58-0.86), area under the Precision-Recall curve (AUPRC) = 0.44. Cross-validated balanced-accuracy, sensitivity and specificity were 0.59, 0.25 and 0.93, respectively, using p = 0.5 to dichotomize the model predicted probabilities (vs 0.71, 0.70 and 0.72, respectively using p = 0.188 according to Youden index). The unsupervised approach identified two clusters, which were not associated with LTP (p = 0.8211) but with the occurrence of per-RFA intra-alveolar hemorrhage, post-RFA cavitations and fistulizations (p = 0.0150). Predictive models using RFs from the post-RFA ablation zone on the first revaluation CT-scan of CRC lung metastases seemed moderately informative regarding the occurrence of LTP. Radiomics approach on interventional radiology data is feasible. However, patterns of heterogeneity detected with RFs on early re-evaluation CT-scans seem biased by different healing processes following benign RFA complications.

CE-454610-1 VENTRICULAR FIBRILLATION REQUIRING EXTRACORPOREAL RESUSCITATION DURING RADIOFREQUENCY ABLATION IN THE CORONARY SINUS

Coronary vasospasm is a rarely reported but potentially catastrophic complication of radiofrequency ablation (RFA). The mechanism is not fully understood but may be related to thermal energy transfer, inflammatory markers released during ablation, and/or alterations in autonomic tone from stimulation of epicardial ganglionated plexi. While most vasospasm occurrences appear subclinical and self-limited, there are exceptions. To highlight an exceptional, life-threatening case of RFA-induced coronary vasospasm. N/A A 62-year-old man with persistent AF and five prior ablations (including one at our institution) presented for ablation of atypical atrial flutter. Termination of the flutter occurred with RFA (7 lesions) at the left atrial roof. There was also a breakthrough of conduction through a prior posterior mitral isthmus line, so coronary sinus (CS) lesions were placed to re-attain mitral block. Two irrigated RF lesions (#1 - 59 seconds, max 26 Watts; #2 - 40 seconds, max 33 Watts) were placed, but 7 seconds into the 3rd lesion (max 27 Watts), ventricular fibrillation (VF) occurred, initially refractory to multiple external shocks. ACLS/CPR commenced. Arterial access was rapidly achieved, and initial coronary angiography simply revealed diffusely slow/no flow related to ongoing VF. Emergent veno-arterial extracorporeal membrane oxygenation (VA ECMO) cannulation was initiated, following which the VF was successfully defibrillated, converting to sinus rhythm. Repeat coronary angiography revealed (known) minimal non-obstructive coronary disease as well as a focal, severe spasm of a dominant left circumflex artery adjacent to the location of CS ablation. Intracoronary nitroglycerin resulted in minimal initial angiographic improvement, so balloon angioplasty and deployment of a drug eluting stent was performed (post: TIMI III flow). The patient made a full recovery and was discharged home on post-procedure day 6 without long-term sequelae. This case underscores a life-threatening complication of RFA within the CS leading to coronary vasospasm and refractory VF. Expedient intervention with extracorporeal resuscitation and support can stabilize patients to allow time to manage arrhythmias and resolve spasm either pharmacologically or procedurally.

PO-04-081 ISOLATION OF PERSISTENT LEFT SIDED SUPERIOR VENA CAVA USING PULSED FIELD ABLATION

Pulmonary vein foci account for more than 90% of triggers for atrial fibrillation, most commonly treated with complete pulmonary vein isolation. Non–pulmonary vein triggers are the drivers of atrial fibrillation in a subgroup of patients. One such trigger is a persistent left superior vena cava (SVC), which may contain remnant muscular and pacemaker tissue carried over from embryonic life. However, reported complications of radiofrequency ablation of this structure are significant, including vein stenosis, tamponade and phrenic nerve injury. Pulsed field ablation is a promising new technology that may be uniquely suited to avoid such a complications. This case illustrates the first known application of pulsed field ablation of a left sided SVC. N/A The patient is a fifty-two year old male with a history of coronary artery disease and persistent atrial fibrillation refractory to medical therapy including rate and rhythm control strategies. He is status post multiple cardioversions with restoration to normal sinus rhythm for a relatively short period of time. The patient underwent an ablation procedure at which time it was discovered that he had an isolated persistent left sided SVC. Pulmonary vein isolation was performed using a combined radiofrequency and pulsed field ablation lattice tip catheter (Affera inc., Watertown, MA). Accordingly to study protocol, lesions were placed using radiofrequency anteriorly and pulsed field lesions posteriorly in the left atrium around the pulmonary veins resulting in complete isolation. The patient also developed a counterclockwise typical atrial flutter which was ablated. Given the propensity for triggers from the SVC, pulsed field ablation was performed by creating a circumferential lesion set superiorly beyond the left superior pulmonary vein region and inferiorly near the mid coronary sinus below the left inferior pulmonary vein. A linear lesion set connecting these two regions was also performed along the atrial portion of the coronary sinus, with subsequent confirmation of exit block and elimination of all local electrograms. In patients with persistent left SVC, pulsed field ablation is feasible without the risk of phrenic nerve injury or tamponade from excessive contact force. Further studies are necessary to examine whether the complications associated with LSVC isolation can be minimized.

PO-01-075 TRANSTHORACIC ECHOCARDIOGRAPHY FOR EARLIER DIAGNOSIS OF ATRIOESOPHAGEAL FISTULA AFTER ABLATION FOR ATRIAL FIBRILLATION

Atrioesophageal fistula (AEF) is a rare complication of radiofrequency ablation for atrial fibrillation (AF). Early diagnosis and surgical management are keys to mitigate progression of this often moribund complication. Although chest CT is the preferred first line imaging tool for diagnosis, AEF symptoms are often variable and counterintuitive which prompts the need to understand echocardiographic findings that may lead to an earlier diagnosis. To report the initial echocardiogram findings of two patients that were ultimately diagnosed with AEF. N/A A 79-year-old male with symptoms AF and gastroesophageal reflux underwent an uneventful pulmonary vein isolation (PVI). Approximately 3 weeks after the ablation, the patient presented to his local hospital with profound fatigue and was found to have nonspecific ST/T changes with an elevated troponin. The transthoracic echocardiogram (TTE) showed moderate left ventricular dysfunction and echo dense microbubbles in the left atrium and ventricle, but not in the corresponding right-sided chambers (Figure A). An emergent CT scan based upon the TTE showed an AEF and he underwent and emergent surgery to repair the AEF. A 49-year-old male underwent a PVI with additional targeting of regions of complex fractionated electrograms on the posterior wall. Two weeks later he developed worsening dyspnea on exertion and chest pain. A CT scan found multiple septic pulmonary emboli and a TTE noted a mobile density crossing the intra-atrial septum. During transfer to our center, he developed progressive respiratory failure and required intubation. Upon arrival he was found to have multiple embolic injuries to his brain and focal neurologic findings. A transesophageal echocardiogram (Figure B) confirmed the mobile density in the right atrium that was an extension of a lesion originating from the posterior left atrium and extending to the iatrogenic atrial septal defect. AEF requires very early diagnosis for survival. In the setting of often non-specific symptoms, such as in these two cases that can lead to an initial incorrect diagnosis, the TTE provided key information to support the underlying diagnosis and guide expedited work-up and intervention.

Clinical Impact of SPECT/CT in Evaluation of Abdominothoracic Fistula.

Abdominothoracic fistula is rarely observed but can be life-threatening. Pleuroperitoneal communication, known to occur in 1.6% of all patients who undergo continuous ambulatory peritoneal dialysis, is an uncommon but well-recognized complication. The most common symptoms are dyspnea and right-sided pleural effusion. A biliopleural fistula is well-described as a complication of radiofrequency ablation and transcatheter arterial chemoembolization of hepatic lesions. It is important to diagnose the cause of pleural effusion early for proper treatment because if the abdominothoracic fistula effusion amount is not large, appropriate diagnosis may be difficult. Here, we introduce 2 cases showing the usefulness of SPECT/CT in evaluating pleuroperitoneal and biliopleural fistulas.

Bleeding Post Radiofrequency Ablation of Inferior Turbinate

Nasal obstruction is a troublesome condition and negatively impacts the quality of life. One of the most important causes is inferior turbinate hypertrophy. Radiofrequency submucosal tissue ablation is an effective technique used to reduce inferior turbinate volume. It is considered a safe, minimally invasive procedure with a low risk of complications. Most of the complications reported were minor such as pain, edema, sneezing, crustation, and bleeding. This study demonstrates a case of major bleeding as a complication of radiofrequency ablation of inferior turbinate aiming to reduce the incidence of such complication. The patient had major bleeding resulting in a drop in hemoglobin level, however, no surgical intervention was required, and he was managed conservatively.

DELAYED-ONSET CORONARY VASOSPASM FOLLOWING RADIOFREQUENCY CATHETER ABLATION OF ATRIAL FIBRILLATION

DELAYED-ONSET CORONARY VASOSPASM FOLLOWING RADIOFREQUENCY CATHETER ABLATION OF ATRIAL FIBRILLATION

472 Proximity Of Coronary Arteries To Tricuspid Annulus As Determined By Computed Tomography

Introduction: Radiofrequency ablation (RFA) is an effective and safe method for treating cardiac arrhythmia. Coronary artery (CA) injury is an underreported complication of RFA. A conventional 8F/4mm ablation catheter can create 5 mm deep and 10 mm wide myocardial lesions. Coronary CT angiography (CCTA) is a safe and noninvasive method to plan RFA and define coronary artery proximity to the tricuspid annulus (TA), a common ablation site.

Esophageal thermal lesions in radiofrequency ablation for atrial fibrillation: A prospective comparative study of thermal sensors

Esophageal thermal lesion (ETL) is a complication of radiofrequency ablation for atrial fibrillation (RFAF). To prospectively compare the incidence of ETL, we used two linear, five- and three-sensor esophageal thermal monitoring catheters (ETMC5 and ETMC3). We also evaluated the predictors of ETL. Patients receiving their first RFAF (n=106) were randomized into two groups, ETMC5 (n=52) and ETMC3 (n=54). Ablation was followed by esophagogastroduodenoscopy within 3 days. Esophageal thermal lesion was detected in 7/106 (6.6%) patients (ETMC5: 3/52 [5.8%] vs. ETMC3: 4/54 [7.4%]; p = 1.0). The maximum temperature and number of measurements>39.0°C did not differ between the groups (ETMC5: 40.5°C and 5.4vs. ETMC3: 40.6°C and 4.9; p=.83 and p=.58, respectively). In ETMC5 group, the catheter had to be moved significantly less often (0.12vs. 0.42; p=.0014) and fluoroscopy time was significantly shorter (79.2min vs. 101.7min; p=.0038) compared with ECMC3 group. The total number of ablations in ETMC5 group was significantly greater (50.2vs. 37.7; p=.030) and ablation time was significantly longer (52.1min vs. 40.1min; p=.0039). Only body mass index (BMI) was significantly different between patients with and without ETL (21.4 ± 2.5vs. 24.3 ± 3.4; p=.022). The incidence of ETL was comparable between ETMC5 and ETMC3 groups; however, fluoroscopy time, total ablation time, and total number of ablations differed significantly. Lower BMI may increase the risk of developing ETL.

Electro-characteristics of Myocardial Pouches and Reduction of the Frequency of Steam Pops During Radiofrequency Ablation.

Background: Radiofrequency ablation (RFA) effectively treats arrhythmia. Steam pop (SP) is a dangerous complication of RFA, which can lead to pericardial tamponade or even death.Objective: This study aimed to explore the electro-characteristics of myocardial pouches, and the relationship between SP, pouch, and impedance.Methods: Swine myocardium was divided into the pouch group and smooth myocardium group. Continuous RFA at 50 W was applied. The initial impedance reduction within the first 3 s of ablation and the time from the start of ablation to SP were recorded. After enabling the delta impedance cutoff function, RFA was performed at different percentage of delta impedance (PDI) cutoff thresholds.Results: The impedance was higher for the pouch myocardium compared to the smooth myocardium (123.22 ± 8.63 Ω and 95.75 ± 4.75 Ω, respectively; p < 0.001). The RFA duration before SPs was shorter in the pouch group compared to the smooth myocardium group [9 s (interquartile range, IQR: 6.25–13 s) and 33 s (IQR: 26.25–40.75 s), respectively; p < 0.001]. Within the first 3 s of RFA, impedance reduction (24.65 ± 6.57 Ω and 12.78 ± 3.35 Ω, respectively; p < 0.001) and PDI [19.18% (IQR: 16.39–24.20%) and 12.96% (IQR: 11.17–14.39%), respectively; p < 0.001] were greater in the pouch group compared to the smooth myocardium group. A PDI of 15% and delta time of 3 s effectively reduced the frequency of SPs without seriously affecting RFA use.Conclusion: SPs occur more frequently in the pouch area during RFA. Appropriate delta impedance cutoff settings (PDI: 15%; delta time: 3 s) can reduce the frequency of SPs and improve the RFA safety.

Efficacy and Safety of Radio Frequency Ablation for Benign Thyroid Nodules: Initial Clinical Experience in United Arab Emirates

Abstract Objectives Radio frequency ablation (RFA) to treat thyroid nodules is well known as one of alternative therapeutic modalities. This study aimed to investigate the efficacy and complications of RFA to treat symptomatic benign thyroid nodules in United Arab Emirates. Materials and Methods Eight-nine benign thyroid nodules of 63 patients were enrolled, who were treated by percutaneous ultrasound (US)-guided RFA from 2017 to 2020, and had following US examinations during 12 months after RFA procedure. Symptomatic score with 10-cm visual scale, cosmetic score with four-point scale, and US findings (nodule diameter, volume, composition and vascularity) were compared before and after RFA procedures. RFA-related complications (hematoma, voice change, hypothyroidism, and hyperthyroidism) were assessed. Statistical Analysis Paired t test was applied to compare laboratory findings before and after RFA procedure. Multiple linear regression analysis was applied to determine significant factors to predict the efficacy of RFA. One-way analysis of variance was applied to compare volume reduction rate (VRR) at 3, 6, and 12 months. Results Symptomatic and cosmetic scores were significantly improved (pre-RFA vs. post-RFA; 6.07 ± 1.89 vs. 2.06 ± 1.09, 2.94 ± 0.84 vs. 1.27 ± 0.51, p&lt; 0.001). Nodule diameter (cm), volume (mL) at pre-RFA, post-RFA 3 months, 6 months, and 12 months were 3.86 ± 1.26, 2.64 ± 1.14, 2.06 ± 1.09, 1.82 ± 1.14, and 18.8 ± 18.79, 8.82 ± 12.42, 4.47 ± 5.59, 4.11 ± 9.17 (p&lt; 0.001). VRR (%) was 52.81 ± 23.48 at post-RFA 3 months, 79.77 ± 16.91 at 6 months, and 82.08 ± 19.54 at 12 months. Composition of solidity was a significant predictive factor, related to VRR at post-RFA 12 months (p = 0.003). Complication rate was 12.7% (8 of 63 patients). Major complications did not occur. Conclusion RFA can be an effective and safe alternative modality to treat benign thyroid nodules, and be preferable to treat symptomatic cystic thyroid nodules in Middle East population.