Robotic approach to catheter ablation

Advances of surgical robotics: image-guided classification and application

Surgical robotics application in the field of minimally invasive surgery has developed rapidly and has been attracting increasingly more research attention in recent years. A common consensus has been reached that surgical procedures are to become less traumatic and with the implementation of more intelligence and higher autonomy, which is a serious challenge faced by the environmental sensing capabilities of robotic systems. One of the main sources of environmental information for robots are images, which are the basis of robot vision. In this review article, we divide clinical image into direct and indirect based on the object of information acquisition, and into continuous, intermittent continuous, and discontinuous according to the target-tracking frequency. The characteristics and applications of the existing surgical robots in each category are introduced based on these two dimensions. Our purpose in conducting this review was to analyze, summarize, and discuss the current evidence on the general rules on the application of image technologies for medical purposes. Our analysis gives insight and provides guidance conducive to the development of more advanced surgical robotics systems in the future.

Catheter ablation for patients with end-stage complex congenital heart disease or cardiomyopathy considered for transplantation: Trials and tribulations

INTRODUCTION

Arrhythmia contributes significantly to morbidity and mortality of patients with congenital heart disease (CHD) or cardiomyopathy (CMP). It also has the potential to worsen symptoms and is particularly detrimental to patients with advanced heart failure awaiting cardiac transplantation. We report our experience using catheter ablation to treat recurrent arrhythmia in patients with CHD or CMP considered for transplantation.

METHODS

Five consecutive patients (3 female, mean age 47.8 ± 12.8 years) with complex CHD or CMP (tricuspid atresia, mitral atresia, double inlet left ventricle, arrhythmogenic right ventricular cardiomyopathy, left ventricular non-compaction) presented with either atrial (n = 3) or ventricular (n = 2) arrhythmias. All ablations were guided by three-dimensional (3D) electro-anatomical mapping, plus remote magnetic navigation in 3 patients.

RESULTS

Patients underwent a median of 2 ablation procedures for a total number of 26 tachycardias. None of the 5 patients experienced further arrhythmia at a median of 939 days (range 4-1375) from their last ablation. During a median follow up of 31 months (range 1-70), three patients underwent successful transplantation at 1375, 1062 and 321 days following their last ablation. One patient with a Fontan circulation died from hepatic cancer and one from end-stage heart failure despite urgent transplant listing.

CONCLUSIONS

Catheter ablation is feasible in complex cardiac patients considered for heart transplantation and should be offered for rhythm management and patient optimization until a suitable donor is found.

Analysis of rotation angles and motions of the flexible mechanisms in bifurcated blood vessels

This article investigates the relationship of rotation angle of two ends of elastic guidewires, and motion method of guidewires and catheters in bifurcated blood vessels. The relationship of rotation angles of the two ends of the guidewire has first been studied by mathematical reasoning, indicating that the rotation angle of the front end of guidewire can be precisely described by that of the rear end. In order to satisfy the requirements of different vascular interventional surgeries, we further investigated a general model of bifurcated human blood vessels. Based on this model, a new motion method, which ensures the guidewire and catheter move cooperatively along center lines of blood vessels to the final target point, has been introduced. Rotation angles of the guidewire in this model were then analyzed. By experiments to verify the functional relationship between rotation angles of two ends of guidewire, the motion method and algorithm of guidewire and catheter are correct. Our study provides references for future studies in fully automated vascular interventional surgeries.

Anatomical Substrates and Ablation of Reentrant Atrial and Ventricular Tachycardias in Repaired Congenital Heart Disease

Advances in surgical repair techniques for various types of congenital heart disease have improved survival into adulthood over the past decades, thus exposing these patients to a high risk of atrial and ventricular arrhythmias later in life. These arrhythmias arise from complex arrhythmogenic substrates. Substrate formation may depend on both pathological myocardial remodelling and variable anatomical boundaries, determined by the type and timing of prior corrective surgery. Accordingly, arrhythmogenic substrates after repair have changed as a result of evolving surgical techniques. Radiofrequency catheter ablation offers an important therapeutic option but remains challenging due to the variable anatomy, surgically created obstacles and the complex arrhythmogenic substrates. Recent technical developments including electroanatomical mapping and image integration for delineating the anatomy facilitate complex catheter ablation procedures. The purpose of this review is to provide an update on the changing anatomical arrhythmogenic substrates and their potential impact on catheter ablation in patients with repaired congenital heart disease and tachyarrhythmias.

Remote magnetic navigation vs. manual navigation for ablation of ventricular tachycardia: a meta-analysis

BACKGROUND

The purpose of this study was to prospectively evaluate the efficacy and safety of remote magnetic navigation (RMN) in comparison with manual catheter navigation (MCN) in performing ventricular tachycardia ablation.

METHODS

An electronic search was performed using PubMed (1948-2013) and EMBASE (1974-2013) studies comparing RMN with MCN which were published prior to 31 December 2013. Outcomes of interest were as follows: acute success, recurrence rate, complications, total procedure and fluoroscopic times. Standard mean difference (SMD) and its 95 % confidence interval (CI) were used for continuous outcomes; odds ratios (OR) were reported for dichotomous variables.

RESULTS

Four non-randomised studies, including a total of 328 patients, were identified. RMN was deployed in 191 patients. Acute success and long-term freedom from arrhythmias were not significantly different between the RMN and control groups (OR 1.845, 95 % CI 0.731-4.659, p = 0.195 and OR 0.676, 95 % CI 0.383-1.194, p = 0.177, respectively). RMN was associated with less peri-procedural complications (OR 0.279, 95 % CI 0.092-0.843, p = 0.024). Shorter procedural and fluoroscopy times were achieved (95 % CI -0.487 to -0.035, p = 0.024 and 95 % CI -1.467 to -0.984, p<0.001, respectively).

CONCLUSION

The acute and long-term success rates for VT ablation are equal between RMN and MCN, whereas the RMN-guided procedure can be performed with a lower complication rate and less procedural and fluoroscopic times. More prospective randomised trials will be needed to better evaluate the superior role of RMN for catheter ablation of ventricular tachycardia.

Tachyarrhythmias and catheter ablation in adult congenital heart disease

Advances in surgical technique have had an immense impact on longevity and quality of life in patients with congenital heart disease. However, an inevitable consequence of these surgical successes is the creation of a unique patient population whose anatomy, surgical history and haemodynamics result in the development of a challenging and complex arrhythmia substrate. Furthermore, this patient group remains susceptible to the arrhythmias seen in the general adult population. It is through a thorough appreciation of the cardiac structural defect, the surgical corrective approach, and haemodynamic impact that the most effective arrhythmia care can be delivered. Catheter ablation techniques offer a highly effective management option but require a meticulous attention to the real-time integration of anatomical and electrophysiological information to identify and eliminate the culprit arrhythmia substrate. This review describes the current approach to the interventional management of patients with tachyarrhythmias in the context of congenital heart disease.

A novel four-wire-driven robotic catheter for radio-frequency ablation treatment

PURPOSE

   Robotic catheters have been proposed to increase the efficacy and safety of the radio-frequency ablation treatment. The robotized motion of current robotic catheters mimics the motion of manual ones-namely, deflection in one direction and rotation around the catheter. With the expectation that the higher dexterity may achieve further efficacy and safety of the robotically driven treatment, we prototyped a four-wire-driven robotic catheter with the ability to deflect in two- degree-of-freedom motions in addition to rotation.

METHODS

   A novel quad-directional structure with two wires was designed and developed to attain yaw and pitch motion in the robotic catheter. We performed a mechanical evaluation of the bendability and maneuverability of the robotic catheter and compared it with current manual catheters.

RESULTS

   We found that the four-wire-driven robotic catheter can achieve a pitching angle of 184.7[Formula: see text] at a pulling distance of wire for 11 mm, while the yawing angle was 170.4[Formula: see text] at 11 mm. The robotic catheter could attain the simultaneous two- degree-of-freedom motions in a simulated cardiac chamber.

CONCLUSION

   The results indicate that the four-wire-driven robotic catheter may offer physicians the opportunity to intuitively control a catheter and smoothly approach the focus position that they aim to ablate.

Arrhythmias in adult congenital heart disease: the year in review

PURPOSE OF REVIEW

Management of arrhythmias is an integral component of care for adults with congenital heart disease (CHD). Our objective was to highlight the important advances from the year 2012 regarding arrhythmias in adult CHD, with a focus on diagnostic considerations, acute management, catheter ablation, and device therapy.

RECENT FINDINGS

During the course of 2012, Holter studies suggested that routine screening was helpful in guiding the clinical decisions for certain patient subgroups, such as adults with tetralogy of Fallot. Supportive evidence was provided for the common practice of anticoagulation and/or screening for intracardiac thrombosis by transesophageal echocardiography prior to electrically cardioverting atrial tachyarrhythmias. Advances in catheter ablation, particularly robotic magnetic navigation, offer new hope for patients in whom access to arrhythmia substrates is not feasible by standard means. The subcutaneous defibrillator emerged as an innovative solution of great interest to the patients at risk of sudden death in whom transvenous lead implantation is unachievable or contraindicated. Finally, 2012 ended with a major milestone: the establishment of physician certification in adult CHD by the American Board of Medical Specialties.

SUMMARY

The year 2012 witnessed important advances in the diagnosis and management of arrhythmias in adults with CHD.

Robotic endovascular surgery

The purpose of this review is to compare conventional endovascular procedures and the robotic endovascular approach in aortic aneurysm repair. Despite advantages over open surgery, conventional endovascular surgery has limitations. To develop an alternative, efforts have been focused on robotic endovascular systems. Two of the 3 studies comparing procedure times demonstrated reduced procedure time in the robotic group, by 6 times ( p < 0.05). One study demonstrated that robotic procedures reduced fluoroscopic exposure time by 12 minute ( p < 0.001). Three in-vitro studies showed that the number of movements required in robotic surgery was reduced up to 10 times ( p < 0.05). One of 2 studies measuring robotic performance score showed a better performance score in the robotic endovascular group ( p = 0.007). These results demonstrate that the robotic technique has multiple advantages over the conventional procedure, including improved catheter stability, a shorter learning curve, reduced procedure time, and better performance in cannulating tortuous vessels. However, robotic endovascular technology may be limited by the cost of the system, the size of the catheter, and the setup time required preoperatively. Further comparative studies between conventional and robotic approaches regarding cost-effectiveness, safety, and performance in cases involving complex anatomy and fenestrated stent grafts are essential. Nevertheless, this revolutionary technology is increasingly popular and may be the next milestone in endovascular surgery.

An engineering view on megatrends in radiology: digitization to quantitative tools of medicine

Within six months of the discovery of X-ray in 1895, the technology was used to scan the interior of the human body, paving the way for many innovations in the field of medicine, including an ultrasound device in 1950, a CT scanner in 1972, and MRI in 1980. More recent decades have witnessed developments such as digital imaging using a picture archiving and communication system, computer-aided detection/diagnosis, organ-specific workstations, and molecular, functional, and quantitative imaging. One of the latest technical breakthrough in the field of radiology has been imaging genomics and robotic interventions for biopsy and theragnosis. This review provides an engineering perspective on these developments and several other megatrends in radiology.

Clinical applications of robotic technology in vascular and endovascular surgery

BACKGROUND

Emerging robotic technologies are increasingly being used by surgical disciplines to facilitate and improve performance of minimally invasive surgery. Robot-assisted intervention has recently been introduced into the field of vascular surgery to potentially enhance laparoscopic vascular and endovascular capabilities. The objective of this study was to review the current status of clinical robotic applications in vascular surgery.

METHODS

A systematic literature search was performed in order to identify all published clinical studies related to robotic implementation in vascular intervention. Web-based search engines were searched using the keywords "surgical robotics," "robotic surgery," "robotics," "computer assisted surgery," and "vascular surgery" or "endovascular" for articles published between January 1990 and November 2009. An evaluation and critical overview of these studies is reported. In addition, an analysis and discussion of supporting evidence for robotic computer-enhanced telemanipulation systems in relation to their applications in laparoscopic vascular and endovascular surgery was undertaken.

RESULTS

Seventeen articles reporting on clinical applications of robotics in laparoscopic vascular and endovascular surgery were detected. They were either case reports or retrospective patient series and prospective studies reporting laparoscopic vascular and endovascular treatments for patients using robotic technology. Minimal comparative clinical evidence to evaluate the advantages of robot-assisted vascular procedures was identified. Robot-assisted laparoscopic aortic procedures have been reported by several studies with satisfactory results. Furthermore, the use of robotic technology as a sole modality for abdominal aortic aneurysm repair and expansion of its applications to splenic and renal artery aneurysm reconstruction have been described. Robotically steerable endovascular catheter systems have potential advantages over conventional catheterization systems. Promising results from applications in cardiac interventions and preclinical studies have urged their use in vascular surgery. Although successful applications in endovascular repair of abdominal aortic aneurysm and lower extremity arterial disease have been reported, published clinical experience with the endovascular robot is limited.

CONCLUSIONS

Robotic technology may enhance vascular surgical techniques given preclinical evidence and early clinical reports. Further clinical studies are required to quantify its advantages over conventional treatments and define its role in vascular and endovascular surgery.

Advances in imaging for atrial fibrillation ablation

Over the last fifteen years, our understanding of the pathophysiology of atrial fibrillation (AF) has paved the way for ablation to be utilized as an effective treatment option. With the aim of gaining more detailed anatomical representation, advances have been made using various imaging modalities, both before and during the ablation procedure, in planning and execution. Options have flourished from procedural fluoroscopy, electroanatomic mapping systems, preprocedural computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and combinations of these technologies. Exciting work is underway in an effort to allow the electrophysiologist to assess scar formation in real time. One advantage would be to lessen the learning curve for what are very complex procedures. The hope of these developments is to improve the likelihood of a successful ablation procedure and to allow more patients access to this treatment.

An in vitro investigation of image-guided steerable catheter navigation

The objective of this study is to provide catheterization with a three-dimensional (3D) guiding image and reduce the collision probability between the catheter tip and vascular wall. A bidirectional steerable catheter was integrated with two magnetic position-tracking sensors on both sides of its bending segment. The tracking information was displayed on the guiding image, which helped the surgeons to determine the relative position between the catheter tip and surrounding vessels. The navigation path was generated on the basis of the vascular skeleton. Moreover, along the path, a series of guiding circular planes were set as the guidance for the catheter. Three operations (bending, advancing, and twisting) were jointly conducted to get the catheter through these guiding planes in turn and eventually into the target vessel. The effectiveness of the proposed navigation method was verified by experiments implemented in an aorta vascular phantom. The navigation system has a mean error of 0.19 mm, a root mean square of 0.49 mm, and a standard deviation of 0.46 mm.

Early experience with robotic navigation for catheter ablation of paroxysmal atrial fibrillation

INTRODUCTION

Pulmonary venous antra isolation (PVAI) is the cornerstone of catheter ablation procedure for drug refractory paroxysmal atrial fibrillation (AF). However, the procedure is technically challenging. Robotic navigation has a potential to expedite and facilitate the procedure.

METHODS

A robotic catheter control system was used for remote navigation-supported PVAI in 22 patients (mean age = 55 +/- 9 years, 16 males, study group). An irrigated-tip catheter with estimate of catheter force on the tissue was used. This was compared in nonrandomized fashion with conventional hand-controlled catheter ablation in 16 patients (mean age = 55 +/- 9 years, 13 males, control group). The procedures were performed under guidance of Ensite NavX navigation system (St. Jude Medical, St. Paul, MN, USA) and intracardiac echocardiography.

RESULTS

Robotic navigation was associated with significantly shorter overall duration of radiofrequency delivery (1,641 +/- 609 vs 2,188 +/- 865 seconds, P < 0.01), shorter total procedural time (207 +/- 29 vs 250 +/- 62 minutes, P = 0.007), fluoroscopy exposure (15 +/- 5 vs 27 +/- 9 minutes, P < 0.001), and lower radiation dose (1,119 +/- 596 vs 3,048 +/- 2,029 mGy/m(2), P < 0.001). No complication was observed in either the study or the control group. During the 5 +/- 1 months follow-up in the study group and 9 +/- 3 months in the control group, 91% and 81% of patients, respectively, were AF free.

CONCLUSIONS

In our early clinical experience, PVAI using a remote robotic catheter navigation was effective, safe, and associated with shorter procedural and fluoroscopic times than conventional PVAI.

A New Actuation Approach for Haptic Interface Design

Traditional haptic interfaces available today use motors to generate forces, while a more recent class of devices uses passive elements to constrain movement. This paper presents a new hybrid actuation approach that combines the use of brakes, springs and motors. The proposed actuation design is potentially safer and more energy efficient than haptic devices that only rely on motors for actuation, and also overcomes many of the rendering limitations displayed by existing passive haptic displays. Applications of this new technology range from devices where safety and reliability are of prime concerns (e.g. large force-feedback interfaces) to devices which can only be powered by limited energy sources such as small batteries (e.g. portable haptic interfaces).

Tactile Feedback Induces Reduced Grasping Force in Robot-Assisted Surgery

Robot-assisted minimally invasive surgery has gained widespread use over the past decade, but the technique is currently operated in the absence of haptic feedback during tissue manipulation. We have developed a complete tactile feedback system, consisting of a piezoresistive force sensor, control system, and pneumatic balloon tactile display, and mounted directly onto a da Vinci surgical robotic system. To evaluate the effect of tactile feedback on robotic manipulation, a group of novices (n = 16) and experts ( n = 4) were asked to perform three blocks of peg transfer tasks with the tactile feedback system in place. Force generated at the end-effectors was measured in all three blocks, but tactile feedback was active only during the middle block. All subjects used higher force when the feedback system was inactive. When active, subjects immediately used substantially less force and still maintained appropriate grip during the task. After the system was again turned off, grip force increased significantly to prefeedback levels. These results demonstrate that robotic manipulations without tactile feedback are done with more force than needed to grasp objects. Therefore, the addition of tactile feedback allows the surgeon to grasp with less force, and may improve control of the robotic system and handling of tissues and other objects.