Ablation catheter-induced mechanical deformation in myocardium: computer modeling and ex vivo experiments.

Cardiac catheter ablation requires an adequate contact between myocardium and catheter tip. Our aim was to quantify the relationship between the contact force (CF) and the resulting mechanical deformation induced by the catheter tip using an ex vivo model and computational modeling. The catheter tip was inserted perpendicularly into porcine heart samples. CF values ranged from 10 to 80 g. The computer model was built to simulate the same experimental conditions, and it considered a 3-parameter Mooney-Rivlin model based on hyper-elastic material. We found a strong correlation between the CF and insertion depth (ID) (R2 = 0.96, P < 0.001), from 0.7 ± 0.3 mm at 10 g to 6.9 ± 0.1 mm at 80 g. Since the surface deformation was asymmetrical, two transversal diameters (minor and major) were identified. Both diameters were strongly correlated with CF (R2 ≥ 0.95), from 4.0 ± 0.4 mm at 20 g to 10.3 ± 0.0 mm at 80 g (minor), and from 6.4 ± 0.7 mm at 20 g to 16.7 ± 0.1 mm at 80 g (major). An optimal fit between computer and experimental results was achieved, with a prediction error of 0.74 and 0.86 mm for insertion depth and mean surface diameter, respectively.

Refractory Autonomic Instability in Mild Traumatic Brain Injury: A Case Report.

Although the specific relationship between concussion and the autonomic nervous system (ANS) has not been fully elucidated, it is generally understood that the pathologic response after a traumatic brain injury (TBI) is linked with systolic cardiac dysfunction. In this case, we present a patient with multiple concussion injuries over a five-year period who exhibited severe cardiac and autonomic dysfunction, in addition to prolonged impairments in vestibular function, oculomotor function, cognitive function, and headaches. The patient is a 28-year-old male with a past medical history of multiple concussions, with the first concussion occurring due to a skiing accident in January 2015. He initially presented in October 2016 after sustaining a concussion due to a motor vehicle accident (MVA) without loss of consciousness (LOC) two weeks prior. In July 2017, the patient was involved in another MVA with a positive head strike and without LOC, causing his third concussion. After each of his first three concussions, he displayed various symptoms that eventually resolved. In October 2020, the patient suffered a syncopal ground-level fall with several minutes of LOC due to dehydration and lightheadedness, leading to his fourth concussion. His fourth concussion resulted in chronic autonomic dysfunction with resting tachycardia refractory to medical management, and he eventually underwent a cardiac ablation. Although the patient underwent a cardiac ablation, his tachycardia and dysautonomia still cause dysfunction in his daily life. With millions of people living with the sequelae of TBI, the recognition and treatment of autonomic dysfunction should be a continued focus in brain injury research.

Outcome of Atrial Fibrillation Ablation in Cancer Patients: A Review.

Atrial fibrillation (AF), a cardiac arrhythmia, exhibits a heightened prevalence among individuals diagnosed with cancer, notably prominent in cases of lung and gastrointestinal malignancies. Robust evidence from extensive studies underscores this association, emphasizing its clinical significance. However, the precise mechanistic underpinnings and specific risk factors linking cancer and AF remain a subject of incomplete understanding. Notably, the prevalence of AF in cancer patients substantially exceeds that in non-cancer counterparts, prompting further exploration of the underlying pathophysiological processes. This review aims to address the existing knowledge void regarding AF management in cancer patients, with a specific focus on the potential role of ablation procedures. While catheter and surgical ablation techniques have been thoroughly investigated and validated as effective treatments within non-cancer populations, their applicability and outcomes in cancer patients have remained inadequately explored. The principal objective of this exhaustive review is to bridge this research gap by conducting a meticulous examination of the feasibility, safety, and effectiveness of ablation interventions for AF in the context of cancer patients. By amalgamating existing evidence and pinpointing critical areas necessitating additional investigation, this review endeavors to provide invaluable insights into AF management in cancer patients, with the ultimate goal of enhancing their clinical care and optimizing outcomes.

Cardiac Tamponade During Catheter Atrial Fibrillation Ablation: A Life-Threatening Complication.

Catheter ablation has become an important treatment strategy for the management of atrial fibrillation (AF) in symptomatic patients. Pulmonary vein isolation (PVI) is increasingly used to restore rhythm in patients with AF and flutter. The serious procedural complication rate has significantly reduced over time and most patients undergo PVI without any adverse events. We present the case of a 70-year-old man with symptomatic AF who underwent elective PVI that was complicated by large pericardial effusion from left atrial appendage (LAA) perforation resulting in cardiac tamponade requiring emergency pericardiocentesis followed by sternotomy to suture the LAA. The perforated LAA was sutured and the LAA was closed surgically through sternotomy by using AtriClip and a large amount of blood was evacuated achieving good cardiac output and hemodynamic stability. A surgical PVI was performed twice restoring normal sinus rhythm. The patient was discharged home, however, he returned to the hospital a few days later with atrial flutter with a rapid ventricular response. He underwent direct current cardioversion (DCCV) and remained in sinus rhythm during the rest of his admission. His bisoprolol was switched to Sotalol to maintain normal sinus rhythm and he was discharged home with outpatient follow-up.

Stenting of critical aortic coarctation in neonates between 600 and 1,350 g. Using a transfemoral artery approach. A single center experience.

Background: Stenting of aortic coarctation (CoA) in newborns with a very low bodyweight remains rare and challenging. In this study we aim to highlight on two points: first the feasibility of CoA stenting in such babies and second the importance of using echocardiogram for guiding the intervention without the need for contrast agent. Methods: Between 2020 and 2022 three preterm babies with very low (VLWB) and extremely low weight (ELWB) underwent CoA-stenting in our center. The weight of the patients at time of intervention was 1,350, 1,200, and 600 g, respectively. The femoral artery was chosen in all patients as vascular access. Transthoracic echocardiography, sonography of the femoral arteries and head ultrasound were applied for follow up. Results: All three interventions were successfully done, with no complications. Coronary stents were implanted. In one Patient (1,350 g) the stent was inserted without sheath. In two patients with renal failure, the stenting was performed under echocardiography-guidance without contrast agent. The follow up showed a preserved function of the left ventricle in all patients. No relevant gradient was reported and no stent re-intervention was required. Sonographic follow up showed a patent femoral artery in all patients. Two patients were operated 73 and 110 days after stenting, and the stents were successfully removed. In the third patient the intervention was performed 130 days ago and he is waiting for the operation. Conclusion: CoA-stenting in VLWB and ELWB is feasible and can bridge them to the next surgery without complications. Echocardiography-guided CoA-stenting in VLWB is a considerate option especially in patients with renal failure. Accessing the femoral artery by experienced doctors, using local anesthesia before the puncture and before removing the sheath might help to protect the vessel from stenosis or occlusion.

Ten Years of Percutaneous Pulmonary Valve Implantation in Australia and New Zealand.

OBJECTIVE: This study sought to investigate the characteristics, morbidity (including the rate of infective endocarditis and valve replacement) and mortality of individuals undergoing percutaneous pulmonary valve implantation in Australia and New Zealand since the procedure has been performed. BACKGROUND: The outcomes of percutaneous pulmonary valve implantation in Australia and New Zealand have not been evaluated. Recent international data, including patients from New Zealand, suggests the rate of infective endocarditis is not insignificant. METHODS: A retrospective multi-site cohort study was undertaken via medical record review at the centres where percutaneous pulmonary valve implantation has been performed. All procedures performed from 2009-March 2018 were included. Individuals were identified from local institution databases. Data was collected and analysed including demographics, details at the time of intervention, haemodynamic outcome, post procedure morbidity and mortality. Multi-site ethics approval was obtained. RESULTS: One hundred and seventy-nine (179) patients attended the cardiac catheter laboratory for planned percutaneous pulmonary valve implantation. Of these patients, 172 underwent successful implantation. Tetralogy of Fallot and pulmonary atresia were the most common diagnoses. The median age at procedure was 19 years (range 3-60 yrs). There was a significant improvement in the acute haemodynamics in patients undergoing percutaneous pulmonary valve implantation for stenosis. Seven (7) patients (3.9%) experienced a major procedural/early post procedure complication (death, conversion to open procedure, cardiac arrest), including two deaths. The annualised rates of infective endocarditis and valve replacement were 4.6% and 3.8% respectively. There was one death related to infective endocarditis in follow-up. CONCLUSIONS: Percutaneous pulmonary valve replacement is a relatively safe method of rehabilitating the right ventricular outflow tract.

[Acute coronary syndrome in the prehospital phase and in the emergency department]. / Das akute Koronarsyndrom in der prähospitalen Phase und in der Notaufnahme.

Acute coronary syndrome is the most common reason for the deployment of emergency medical services in Germany. Approximately 20-25% of all medical emergencies result from the indications for the suspicion of acute coronary syndrome. A substantial proportion of the total mortality rate is observed in the preclinical phase. Consequently, targeted diagnostics and treatment are of particular importance in this early phase. This article provides recommendations for the approach to patients with acute coronary syndrome in the prehospital phase and in the emergency department.

[Transcatheter mitral valve replacement : Indications, options, and techniques as well as important aspects for perioperative care]. / Interventioneller Mitralklappenersatz : Indikationen, Möglichkeiten und Technik sowie wichtige Aspekte für die perioperative Betreuung.

Transcatheter therapy of the mitral valve is more challenging compared to the aortic valve. Interventional therapy with the Mitra-Clip system, mimicking the surgical edge-to-edge repair, was first introduced in 2003 and received the CE mark in 2008. The first implantation of the Tendyne system, which is currently the only commercially available system for mitral valve replacement, was performed in 2014, and routine clinical use was approved in 2020. Several new valve platforms are in clinical development and will expand the treatment portfolio. This article will discuss the clinical indications, technical challenges and specific requirements for perioperative management.

Exploring telerobotic cardiac catheter ablation in a rural community hospital: A pilot study.

Background: Telerobotic surgery could improve access to specialty procedures such as cardiac catheter ablation in rural and underserved regions in the United States and worldwide. Advancements in telecommunications, internet infrastructure, and surgical robotics are lowering the technical hurdles for this future healthcare delivery paradigm. Nonetheless, important questions remain regarding the safe implementation of telerobotic surgery in rural community hospital settings. Objective: The purpose of this study was to pilot test a system and methods to explore telerobotic cardiac catheter ablation in a rural community hospital setting. Methods: We assembled a portable preclinical telerobotic catheter ablation system from commercial-grade components using third-party vendors. We then carried out 4 telerobotic surgery simulations with an urban surgeon and a rural community hospital operating room (OR) team spanning a distance of more than 2000 miles. Two challenge scenarios were incorporated into the simulations, including loss of network connection and cardiac perforation with subsequent life-threatening tamponade physiology. An ethnographic analysis was then performed. Results: Interviews and observations suggested that rural OR teams readily adapt to the telesurgery context. However, participant perceptions of team trust, communication, and emergency management were significantly altered by the remote location of the surgeon. In addition, most participants believed the OR team would have been better equipped for the challenges had they received formal training or had prior experience with the procedure being simulated. Conclusion: We demonstrate the utility and feasibility of a system and methods for studying specialty telerobotic surgery in a rural hospital OR setting.

Computer simulations of an irrigated radiofrequency cardiac ablation catheter and experimental validation by infrared imaging.

PURPOSE: To develop and validate a three-dimensional (3-D) computer model based on accurate geometry of an irrigated cardiac radiofrequency (RF) ablation catheter with microwave radiometry capability, and to test catheter performance. METHODS: A computer model was developed based on CAD geometry of a RF cardiac ablation catheter prototype to simulate electromagnetic heating, heat transfer, and computational fluid dynamics (blood flow, open irrigation, and natural convection). Parametric studies were performed; blood flow velocity (0-25 cm/s) and irrigation flow (0-40 ml/min) varied, both with perpendicular (PE) and parallel (PA) catheter orientations relative to tissue. Tissue Agar phantom studies were performed under similar conditions, and temperature maps were recorded via infrared camera. Computer model simulations were performed with constant voltage and with voltage adjusted to achieve maximum tissue temperatures of 95-105 °C. RESULTS: Model predicted thermal lesion width at 5 W power was 5.8-6.4 mm (PE)/6.5-6.6 mm (PA), and lesion depth was 4.0-4.3 mm (PE)/4.0-4.1 mm (PA). Compared to phantom studies, the mean errors of the computer model were as follows: 6.2 °C(PE)/4.3 °C (PA) for maximum gel temperature, 0.7 mm (10.9%) (PE)/0.1 mm (0.8%) (PA) for lesion width, and 0.3 mm (7.7%)(PE)/0.7 mm (19.1%) (PA) for lesion depth. For temperature-controlled ablation, model predicted thermal lesion width was 7-9.2 mm (PE)/8.6-9.2 mm (PA), and lesion depth was 4.3-5.5 mm (PE)/3.4-5.4 mm (PA). CONCLUSIONS: Computer models were able to reproduce device performance and to enable device evaluation under varying conditions. Temperature controlled ablation of irrigated catheters enables optimal tissue temperatures independent of patient-specific conditions such as blood flow.

A Soft Resistive Sensor with a Semicircular Cross-Sectional Channel for Soft Cardiac Catheter Ablation.

The field of soft robotics has attracted the interest of the medical community due to the ability of soft elastic materials to traverse the abnormal environment of the human body. However, sensing in soft robotics has been challenging due to the sensitivity of soft sensors to various loading conditions and the nonlinear signal responses that can arise under extreme loads. Ideally, soft sensors should provide a linear response under a specific loading condition and provide a different response for other loading directions. With these specifications in mind, our team created a soft elastomeric sensor designed to provide force feedback during cardiac catheter ablation surgery. Analytical and computational methods were explored to define a relationship between resistance and applied force for a semicircular, liquid metal filled channel in the soft elastomeric sensor. Pouillet's Law is utilized to calculate the resistance based on the change in cross-sectional area resulting from various applied pressures. FEA simulations were created to simulate the deformation of the sensor under various loads. To confirm the validity of these simulations, the elastomer was modeled as a neo-Hookean material and the liquid metal was modeled as an incompressible fluid with negligible shear modulus under uniaxial compression. Results show a linearly proportional relationship between the resistance of the sensor and the application of a uniaxial force. Altering the direction of applied force results in a quadratic relationship between total resistance and the magnitude of force.

Canadian national electrophysiology ablation registry report 2011-2016.

BACKGROUND/PURPOSE: Interventional cardiac electrophysiology (EP) is a rapidly evolving field in Canada; a nationwide registry was established in 2011 to conduct a periodic review of resource allocation. METHODS: The registry collects annual data on EP lab infrastructure, imaging, tools, human resources, procedural volumes, success rates, and wait times. Leading physicians from each EP lab were contacted electronically; participation was voluntary. RESULTS: All Canadian EP centres were identified (n = 30); 50 and 45 % of active centres participated in the last 2 instalments of the registry. A mean of 508 ± 270 standard and complex catheter ablation procedures were reported annually for 2015-2016 by all responding centres. The most frequently performed ablation targets atrial fibrillation (PVI) arrhythmia accounting for 36 % of all procedures (mean = 164 ± 85). The number of full time physicians ranges between 1 and 7 per centre, (mean = 4). The mean wait time to see an electrophysiologist for an initial non-urgent consult is 23 weeks. The wait time between an EP consult and ablation date is 17.8 weeks for simple ablation, and 30.1 weeks for AF ablation. On average centres have 2 (range: 1-4) rooms equipped for ablations; each centre uses the EP lab an average of 7 shifts per week. While diagnostic studies and radiofrequency ablations are performed in all centres, point-by-point cryoablation is available in 85 % centres; 38 % of the respondents use circular ablation techniques. CONCLUSIONS: This initiative provides contemporary data on invasive electrophysiology lab practices. The EP registry provides activity benchmarks on national trends and practices.

Transcatheter utilisation of lifetech multifunction™ occluder device for closure of perimembranous and muscular ventricular septal defects: first use in North America.

Transcatheter closure of ventricular septal defects is considered first-line therapy when anatomically appropriate but is often challenged by proximity to the conduction system in perimembranous defects, or irregular defect shape, especially residual defects that may remain post-operatively. Advancements in device design, however, have allowed for significant improvements in deployment techniques and overall safety. Here we describe the first use of the Lifetech Konar-multifunction™ occluder device in North America, and our specific use of this device to close complex post-operative muscular and a perimembranous-ventricular septal defects in the same patient.

Catheter Ablation in Patients With Neuroendocrine (Carcinoid) Tumors and Carcinoid Heart Disease: Outcomes, Peri-Procedural Complications, and Management Strategies.

OBJECTIVES: This report describes a series of patients with neuroendocrine tumors with or without carcinoid heart disease undergoing catheter ablation at the authors' institution. BACKGROUND: Neuroendocrine (carcinoid) tumors are a rare form of neoplasm with the potential for systemic vasoactive effects and cardiac valvular involvement. These tumors can create peri-operative management challenges for the electrophysiologist. However, there are few data regarding ablation outcomes, periprocedural complications, and management of these patients. METHODS: All patients with neuroendocrine tumors undergoing catheter ablation at the Mayo Clinic, Rochester, Minnesota over a 25-year period were retrospectively reviewed. From this cohort, the type of arrhythmias ablated, the recurrence of arrhythmia, perioperative complications, and mortality were reviewed and analyzed. RESULTS: A total of 17 patients (52.9% male; mean age 62.4 ± 9.3 years) with neuroendocrine tumors underwent catheter ablation during the study period. Primary tumor sites included the gastrointestinal tract (n = 11), lung (n = 4), ovary (n = 1), and lymph node (n = 1). Nine patients had metastatic disease, 5 of whom were on somatostatin analog therapy at the time of ablation. Three patients had active symptoms of carcinoid syndrome at the time of ablation, and 2 of those patients had carcinoid heart disease. Ablations were performed mainly for atrial arrhythmias (76.5%): atrioventricular nodal re-entry tachycardia (n = 7), atrial fibrillation (n = 4), and atrial flutter (n = 2). Four patients underwent ablation of ventricular arrhythmias. During a mean follow-up of 19.2 ± 26.2 months, arrhythmia recurred in 35.3% of patients. Three patients (17.6%) had periprocedural complications: pericardial effusion (n = 1), groin site hematoma (n = 1), and carcinoid crisis (n = 1). No deaths were noted in the peri-operative period. CONCLUSIONS: In a unique cohort of patients with neuroendocrine tumors, catheter ablation was feasible in patients with or without carcinoid syndrome. Carcinoid crisis may occur during the periprocedural period, which can be life-threatening, and a specified protocol for management is important to mitigate this risk.

Efficacy of medical and ablation therapy for inappropriate sinus tachycardia: A single-center experience.

BACKGROUND: Effective therapy for inappropriate sinus tachycardia (IST) remains challenging with high rates of treatment failure and symptom recurrence. It is uncertain how effective pharmacotherapy and procedural therapy are long-term, with poor response to medical therapy in general. METHODS: We retrospectively reviewed all patients with the diagnosis of IST at a tertiary academic medical center from 1998 to 2018. We extracted data related to prescribing patterns and symptom response to medical therapy and sinus node modification (SNM), assessing efficacy and periprocedural complication rates. RESULTS: A total of 305 patients with a formal diagnosis of IST were identified, with 259 (84.9%) receiving at least one prescription medication related to the condition. Beta-blockers were the most commonly used medication (n = 245), with a majority of patients reporting no change or worsening of symptoms, and poor response was seen to other medication classes. Improvement was seen significantly more often with ivabradine than beta blockers, though the sample size was limited (p = .003). Fifty-five patients (18.0% of all IST patients), mean age 32.0 ± 9.1 years, underwent a SNM procedure, with an average of 1.8 ± 0.9 procedures per patient. Acute symptomatic improvement (<6 months) was seen in 58.2% of patients. Long-term complete resolution of symptoms was seen in 5.5% of patients, modest improvement in 29.1%, and no long-term benefit was seen in 65.5% of patients. CONCLUSIONS: Among all medical therapies, there were high rates of treatment failure or symptom worsening in over three-quarters of patients in our study. Ivabradine was most beneficial, though the sample size was small. While most patients receiving SNM ablation for IST perceive an acute symptomatic improvement, almost two-thirds of patients have no long-term improvement, and resolution of symptoms is quite rare. AV node ablation with pacemaker implantation following lack of response to SNM offered increased success, though the sample size was limited.

Feasibility and Safety of Distal Radial Artery Access in Anatomical Snuffbox for Coronary Angiography and Coronary Intervention.

BACKGROUND: There is limited data on feasibility and safety of coronary interventions performed using radial artery at anatomical snuffbox as vascular access point in South Asian region. Our study attempts to evaluate the feasibility and safety of coronary angiography and percutaneous coronary intervention using transradial access at anatomical snuffbox. METHODS: Transradial access at anatomical snuffbox was attempted in 128 consecutive patients, who were planned for coronary angiography and/or percutaneous coronary intervention. Success in vascular access, completion of planned procedure and complications encountered, including patency of radial artery after the procedure, were investigated. RESULTS: A total of 128 patients (76 males [59.4%]; 52 females [40.6%]) between 44-78 years of age (mean age, 59.0 +/- 10.2 years) were included in the study. Distal radial artery puncture and sheath placement was successful in all patients however planned procedure was completed in 126 (98.4%) patients. Total 90 coronary angiographies and 36 percutaneous coronary interventions were performed of which five were primary percutaneous coronary intervention. We encountered brachial artery spasm among two patient (1.5%) and significant pain and swelling among three patients (2.3%). No bleeding complication, numbness or parasthesia were observed on follow-up. Patients had average pain rating of 2.4+/- 1.1 in visual analogue pain rating scale. There were no instances of radial artery occlusion after the procedure. CONCLUSIONS: Distal radial artery, at anatomical snuffbox, is a safe and feasible alternative vascular access site for coronary angiography and percutaneous coronary intervention.

Gaps in patient-reported outcome measures in randomized clinical trials of cardiac catheter ablation: a systematic review.

The aim of this systematic review was to evaluate randomized clinical trials (RCTs) of cardiac catheter ablation (CCA) and to assess the prevalence, characteristics and reporting standards of clinically relevant patient-reported outcome measures (PROMs). Electronic database searches of Medline, Embase, CENTRAL, and the WHO Trial Registry were conducted in March 2019. The study protocol was registered on PROSPERO (CRD42019133086). Of 7125 records identified, 237 RCTs were included for analysis, representing 35 427 patients with a mean age of 59 years. Only 43 RCTs (18%) reported PROMs of which 27 included a generic PROM that measured health-related quality of life (HRQL) necessary to conduct comparative effectiveness research. There was notable under-representation of certain patient groups-only 31% were women and only 8% were of non-Caucasian ethnicity, in trials which reported such data. The reporting standard of PROMs was highly variable with 8-62% adherence against CONSORT PRO-specific items. In summary, PROMs play a crucial role in determining the clinical and cost-effectiveness of treatments which primarily offer symptomatic improvement, such as CCA. Their underuse significantly limits evaluation of the comparative effectiveness of treatments. Using CCA as an exemplar, there are additional issues of infrequent assessment, poor reporting and under-representation of many population groups. Greater use of PROMs, and specifically validated HRQL questionnaires, is paramount in giving patients a voice in studies, generating more meaningful comparisons between treatments and driving better patient-centred clinical and policy-level decision-making.

The impact of the COVID-19 pandemic upon patients, staff, and on the future practices of percutaneous coronary intervention.

The COVID pandemic in 2020 had unpredictable consequences on the presentation and management of patients with ischaemic heart disease. Subsequent to these initial responses the impact of the initial pandemic can be reviewed and responses can be considered. It is clear that there are new opportunities for optimising patient management pathways and in particular enhanced use of information technology. Changes in attitudes towards health and perceived risk are evident within both the catheter lab teams and our patient cohorts. Summating both the intellectual and emotional experiences of the pandemic are essential to prepare for either a second wave of COVID 19 or any new pandemic threat in the future.

Interatrial Shunt Device for Heart Failure With Preserved Ejection Fraction.

Heart failure with preserved ejection fraction (HFpEF) accounts for approximately half of the current burden of HF, and the prevalence is continuing to rise. In contrast to HF with reduced ejection fraction (HFrEF) there are no clinically effective evidence based therapies for HFpEF. The principal pathophysiologic disorder is an elevation of left atrial pressure, most notable during physical activity, which results from impaired left ventricular diastolic reserve, and increased left atrial stiffness. This review outlines the clinical development of a potential device based therapy for HFpEF, the interatrial shunt device (IASD).

Removing an Entrapped Pigtail Catheter by Re-enforcing a Traditional Method.

Right heart catheterization is the main step in the evaluation of pulmonary hypertension including Chronic Thromboembolic Pulmonary Hypertension (CTEPH) and is considered a relatively safe procedure. Complications can occur including perforation, tamponade, bleeding, etc. requiring different types of interventions such as manipulation or surgery. Here, we have described a case of pigtail catheter entrapment and the method we used to free it without invasive measures.