Ann Thorac Surg 2009;88:1317-1321. doi:10.1016/j.athoracsur.2009.04.066
© 2009 The Society of Thoracic Surgeons
New Technology
A New Vacuum-Assisted Probe for Minimally Invasive Radiofrequency Ablation
Stefano Bevilacqua, MDa,*,
Tommaso Gasbarri, MDa,
Alfredo Giuseppe Cerillo, MDa,
Massimiliano Mariani, MDb,
Michele Murzi, MDa,
Tommaso Nannini, MDa,
Mattia Glauber, MDa
a Adult Cardiac Surgery Department, Heart Hospital G. Pasquinucci, G. Monasterio Foundation, National Research Council, Massa, Italy
b Adult Cardiology Department, Heart Hospital G. Pasquinucci, G. Monasterio Foundation, National Research Council, Massa, Italy
Accepted for publication April 9, 2009.
* Address correspondence to Dr Bevilacqua, Adult Cardiac Surgery Department, Heart Hospital G. Pasquinucci, G. Monasterio Foundation, via Aurelia Sud, Massa, 54100, Italy (Email: bevilacqua{at}ifc.cnr.it).
 |
Abstract
|
|---|
Purpose: The Cobra Adhere XL (Estech, San Ramon, CA) is a multiple-electrode, temperature-controlled, monopolar radiofrequency probe with a vacuum-assisted stabilization system. We evaluated this new technology for epicardial ablation of atrial fibrillation in mitral valve patients through a right mini-thoracotomy.
Description: Between June and August 2008, 12 patients underwent minimal invasive surgery for mitral disease and ablation for atrial fibrillation with the Cobra Adhere XL (Estech). Three patients had paroxysmal atrial fibrillation. Off-pump pulmonary vein isolation was performed with an epicardial oval lesion parallel to the mitral plane. In 10 patients, an endocardial lesion to the mitral annulus was added.
Evaluation: There were no operative deaths or major postoperative complications. At a mean follow-up of 8.76 ± 1.0 months, 11 patients (91.67%) were in stable sinus rhythm. Echocardiography underscored a complete recovery of atrial transport function in most of these patients (90.91%). No major cardiac and cerebrovascular events occurred during follow-up.
Conclusions: Left-side ablation combined with minimally invasive surgery for mitral disease can be easily, safely, and effectively performed with the Cobra Adhere XL probe.
|
Introduction
|
|---|
Minimally invasive surgery is becoming a broadly diffused procedure to approach complex valve disease. The development of new ablative technologies to simplify the original "cut and sew" Cox maze procedure has lead to routine treatment of atrial fibrillation (AF) in patients undergoing open heart surgery or as a stand-alone arrhythmia. The open competition with percutaneous strategies has led surgeons to refine a valid minimally invasive surgical platform for AF treatment.
We presently report the use of a novel monopolar radiofrequency vacuum-assisted system for epicardial off-pump ablation using a right mini-thoracotomy access, called the Cobra Adhere XL (Estech, San Ramon, CA).
|
Technology
|
|---|
Patients and Methods
Between June and August 2008, 27 patients underwent minimally invasive surgery for isolated mitral or mitral plus tricuspid valve disease through a right mini-thoracotomy in the third intercostal space. Of these, 12 received an ablation procedure for AF with the Cobra Adhere XL probe (Estech). The study was approved by the local Ethical Committee, and all patients signed an informed consent to receive the ablation procedure. Table 1
shows preoperative and operative data.
Technology
The Cobra Adhere XL is a multiple-electrode, temperature-controlled, monopolar radiofrequency probe with a vacuum-assisted stabilization system that improves the contact with atrial tissue and optimizes the power penetration in the myocardium (Fig 1). The probe has an internal cooling system with continuous saline irrigation (500 mL/h) to reduce temperature at tissue-electrode interface, allowing greater energy delivery and larger and deeper lesions. The probe is specifically designed for use on the beating heart to neutralize the cooling effect of circulating blood. The probe is connected to the Cobra Electrosurgical Unit (Estech). Table 2
shows the relation between temperature, time, and depth of lesions in animal models. The probe performs a single epicardial lesion encircling all four pulmonary veins in a plane parallel to the mitral valve annulus (Fig 2).
View larger version (89K):
[in this window]
[in a new window]
|
Fig 1. The Cobra Adhere XL system (Estech, San Ramon, CA) with probe, vacuum cuff and soft pre-curved guide.
|
|
|
Technique
|
|---|
Surgical Technique
The chest was entered through a 6-cm to 8-cm mini-thoracotomy in the third intercostal space. Percutaneous cannulation of venae cavae through the right common femoral vein with a dual stage RAP cannula (Estech, San Ramon, CA) and direct cannulation of the aorta with the EasyFlow cannula (Estech, San Ramon, CA) or Straight-shot cannula (Heartport Inc, Redwood City, CA) were routinely performed. The aorta was directly cross clamped with a flexible clamp (Cygnet, Novare Surgical System Inc, Cupertino, CA), and the heart was arrested with antegrade cold crystalloid cardioplegia (Custodiol HTK Solution, Essential Pharmaceuticals, LLC, Newtown, PE). During aortic cross-clamp time, carbon dioxide was inflated into the thorax at 2 L/min. A thoracoscopic 30° camera was inserted through a 5-mm port.
Ablation Technique
The ablation procedure was completed after cannulation before starting cardiopulmonary bypass. Pericardial reflections were bluntly dissected to access the transverse and oblique sinuses. A pre-curved "J-shaped" soft guide over a malleable mandrel was introduced in the transverse sinus underneath the superior vena cava. At the left end of the sinus, the mandrel was retracted and the soft guide, with the pre-curved tip oriented caudo-dorsally, advanced toward the oblique sinus. Under thoracoscopic view, the tip of the guide was retrieved underneath the inferior vena cava. After connection to the guide, with a "push and pull" technique, the probe was inserted around the four pulmonary veins, on a plane parallel to the mitral valve and posterior to the left atrial appendage. Probe position relative to the left appendage was endoscopically visualized and controlled also with transesophageal echocardiography (Fig 3). The probe is formed by two series (proximal and distal) of five electrodes that were activated sequentially without moving the probe. The generator was set to maintain the tissue at 70°C for 90 seconds. The power of energy supplied was automatically determined by the machine. During the ablation, the vacuum stabilizer was maintained at –600 mm Hg. The circumferential lesion was completed by moving the probe to overlap the two extremities of the previous lesions.
View larger version (126K):
[in this window]
[in a new window]
|
Fig 3. Transesophageal view of the probe in the correct position between the right superior pulmonary vein and the left appendage.
|
|
The completeness of the lesion and the presence of complete exit block was assessed with epicardial over-pacing of the left atrium dome only in patients in sinus rhythm (ie, 3 patients with paroxysmal AF and 1 patient with persistent AF who was in sinus rhythm at admission). No electrical cardioversion was intraoperatively attempted. This test was conducted with a bipolar pacing probe (AFfirm [Estech, San Ramon, CA]). In 3 patients the block was confirmed, and in 1 patient an additional energy application was required.
In all patients with persistent and long-lasting persistent paroxysmal AF, and in 1 patient with paroxysmal AF with a 56-mm left atrial diameter, a left isthmus line was added from the endocardial side. This lesion was performed with the same probe without vacuum suction, using a setting at 70°C temperature for only 60 seconds. Vacuum suction was stopped because it was not useful in the arrested heart to avoid lesions that were too deep with potential damage to coronary arteries. The exact location of isthmus lesion was tailored to angiographic coronary anatomy, as described by Benussi and coworkers [1]. In most cases the left appendage was excluded with a polypropylene double mattress suture from the endocardial side.
All procedures were performed on transesophageal echocardiography monitoring for excluding preoperative presence of clots in the left appendage and documenting complete appendage exclusion after the operation. The transesophageal echocardiography probe was retracted during radiofrequency application.
Statistical Analysis
Analysis of data was performed with the StatView 4 Software (SAS Institute, Cary, NC). Data are reported as mean ± standard deviation.
|
Clinical Experience
|
|---|
There was no operative death. No postoperative complications occurred, except for a patient who presented with transient neuropsychological damage with confusion and motor hyperactivity. The mean length of hospital stay was 6.58 ± 1.31 days. All patients were discharged home. Six patients (50%) had AF in the postoperative period. All these patients received intravenous amiodarone. Sinus rhythm was restored in 3 patients. At hospital discharge, 3 patients (25%) had AF and 1 (8.33%) was in atrial flutter (Table 3). No electrical cardioversion was attempted in this early postoperative phase. All patients received warfarin for at least 6 months with a target international normalized ratio of 2.5 to 3.
The mean follow-up of 8.76 ± 1.00 months (range, 6.89 to 9.86) was 100% complete. The evaluation was performed on a regular basis at 1, 3, 6, and 9 months, and each year with echocardiography, electrocardiogram, and 24 hour-Holter electrocardiogram. Follow-up was ended on March 31, 2009. One patient, discharged in atrial flutter on amiodarone and beta-blockers, was in sinus rhythm at the 1-month visit. Approximately 3 months after the operation, 2 patients underwent successful electrical cardioversion with sinus rhythm restoration. The last patients discharged in AF refused electrical cardioversion (Table 3). At the end of the follow-up, 11 patients (91.67%) were in sinus rhythm, with only 2 patients receiving amiodarone. Freedom from AF was 100% for paroxysmal patients (3 of 3) and 88.89% (8 of 9) for persistent and long-lasting persistent AF. Echocardiography assessment at follow-up underscored a complete recovery of atrial transport function in all patients in sinus rhythm, except one showing atrial paralysis (10 of 11 patients [90.91%]).
During follow-up, no major cardiac and cerebrovascular events occurred. Most of the patients were in New York Heart Association functional class I with only 1 patient (8.33%) complaining of effort dyspnea (New York Heart Association functional class II).
|
Comment
|
|---|
Surgical ablation of paroxysmal or persistent AF has a clear indication in symptomatic and selected low-risk asymptomatic patients undergoing cardiac surgery for other reasons. Surgical treatment of stand-alone AF is advocated only in symptomatic patients preferring surgery to percutaneous ablation or patients who have failed one or more catheter ablations or who showed clear contraindication to percutaneous procedures (eg, thrombi in left atrial appendage) [2]. Different minimally invasive surgical techniques with different ablative devices have been proposed [3, 4].
Wolf and colleagues [5] reported a series of patients treated with a bipolar radiofrequency clamp using a bilateral approach and a video-assisted technique, with 91% freedom from AF at 3 months. Similar results with a 97.6% long-term freedom from AF are reported by Ad and Cox [6] with cryoablation.
Epicardial radiofrequency ablation with irrigated probe has demonstrated up to 86% of transmural lesions in the animal model [7]. Clinical use of conventional epicardial radiofrequency ablation on the beating heart has shown a 3-year freedom from AF of 77% [8].
The Cobra Adhere XL probe can represent an easy and reproducible tool to perform left-sided ablation in concomitant and stand-alone cases of AF. Internal cooling and vacuum-assisted stabilization provides an efficacious use on the beating heart reducing ischemic time with respect to the endocardial approach as with cryotherapy and monopolar radiofrequency. The limited anatomic dissection to introduce the probe and the monolateral approach can offer significant advantages respect to bipolar clamps in terms of time and technical complexity.
The present report aims to describe this new tool that can enrich the surgical armamentarium for AF treatment. Despite the encouraging clinical results, however, further, larger, and prospective studies are needed to evaluate the real efficacy of this new technology.
|
Disclosures and Freedom of Investigation
|
|---|
All tested materials were regularly purchased with institutional funds of the Heart Hospital—Fondazione G. Monasterio. The authors have performed an independent prospective evaluation of the technology. The authors have no financial relationship with the Estech Company.
|
Footnotes
|
|---|
Disclaimer The Society of Thoracic Surgeons, the Southern Thoracic Surgical Association, and The Annals of Thoracic Surgery neither endorse nor discourage use of the new technology described in this article.
|
References
|
|---|
- Benussi S, Nascimbene S, Calvi S, Alfieri O. A tailored anatomical approach to prevent complications during left atrial ablation Ann Thorac Surg 2003;75:1979-1981.[Abstract/Free Full Text]
- Calkins H, Brugada J, Packer DL, et al. HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for personnel, policy, procedures and follow-up Europace 2007;9:335-379.[Free Full Text]
- Loulmet DF, Patel NC, Patel NU, et al. First robotic endoscopic epicardial isolation of the pulmonary veins with microwave energy in a patient in chronic atrial fibrillation Ann Thorac Surg 2004;78:e24-e25.[Abstract/Free Full Text]
- Pruitt JC, Lazzara RR, Dworkin GH, et al. Totally endoscopic ablation of lone atrial fibrillation: initial clinical experience Ann Thorac Surg 2006;81:1325-1330.[Abstract/Free Full Text]
- Wolf RK, Schneeberger EW, Osterday R, et al. Video-assisted bilateral pulmonary vein isolation and left atrial appendage exclusion for atrial fibrillation J Thorac Cardiovasc Surg 2005;130:797-802.[Abstract/Free Full Text]
- Ad N, Cox JL. The maze procedure for the treatment of atrial fibrillation: a minimally invasive approach J Card Surg 2004;19:196-200.[Medline]
- Ishikawa S, Oki S, Muraoka M, Oshima K, Kashiwabara K, Morishita Y. Epicardial radiofrequency ablation on a beating heart: an experimental study Ann Thorac Cardiovasc Surg 2005;11:21-24.[Medline]
- Benussi S, Nascimbene S, Agricola E, et al. Surgical ablation of atrial fibrillation using the epicardial radiofrequency approach: mid-term results and risk analysis Ann Thorac Surg 2002;74:1050-1056.[Abstract/Free Full Text]
This article has been cited by other articles:
|
|
|
|
 
G. Nasso, R. Bonifazi, A. Del Prete, G. Del Prete, V. Lopriore, F. Bartolomucci, A. M. Calafiore, and G. Speziale
Long-term results of ablation for isolated atrial fibrillation through a right minithoracotomy: Toward a rational revision of treatment protocols
J. Thorac. Cardiovasc. Surg.,
August 1, 2011;
142(2):
e41 - e46.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Yilmaz, G. S. C. Geuzebroek, B. P. Van Putte, L. V. A. Boersma, U. Sonker, J. M. T. De Bakker, and W.-J. Van Boven
Completely thoracoscopic pulmonary vein isolation with ganglionic plexus ablation and left atrial appendage amputation for treatment of atrial fibrillation
Eur J Cardiothorac Surg,
September 1, 2010;
38(3):
356 - 360.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Bevilacqua, A. G. Cerillo, M. Solinas, and M. Glauber
Epicardial radiofrequency ablation and aortic valve replacement through right mini-thoracotomy
Interact CardioVasc Thorac Surg,
July 1, 2010;
11(1):
1 - 2.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
