Different Surgical Techniques for Ablation.ppt

Surgical Techniques for Ablation

1. 1
Surgical Techniques for Ablation
Daniel J. Beckman, MD, FACS
Director, Surgical Electrophysiology
CorVasc
Indianapolis, Indiana

2. 2
Introduction: Surgical Ablation Techniques for Atrial
Fibrillation (AF)
●The maze procedure, its history, and its pathophysiologic
underpinnings
●The Cox maze III procedure
●New approaches to the surgical ablation of AF, including
radiofrequency (RF), laser, ultrasound, cryothermy, and microwave
energy techniques
●Efficacy of the new surgical ablation procedures
●Safety of the new surgical ablation procedures
●Technical advantages of the new surgical ablation procedures

3. 3
History of the Maze Procedure
●The maze procedure was developed by James Cox and first used in a
patient in 1987
1
●It was designed as an open-heart operation via a median sternotomy
●The surgical technique was largely cut-and-sew
●The aim was to create an electrical maze by making strategically
placed incisions within the atria
1
●The maze procedure has undergone 2 modifications, evolving into the
Cox maze III procedure
2
●The maze III procedure has achieved an efficacy rate of approximately
90%
2
1. Cox JL, et al. J Thorac Cardiovasc Surg. 1991;101:569-583.
2. Sundt TM, et al. Cardiol Clin. 1997;15:739-748.

4. 4
The Pathophysiologic Basis of the Maze Procedure
●The maze procedure was the product of electrophysiologic studies of
the 3 proposed mechanisms of atrial activation in AF
1
:
—The rapid discharge of a single ectopic focus in the atrium
—A single left atrial mother wave generating spirals that produce fibrillatory
waves in the right atrium
—Intra-atrial reentry circuits (random, macro-)
Sundt TM, et al. Cardiol Clin. 1997;15:739-748.

5. 5
The Pathophysiologic Basis of the Maze Procedure
●The surgical approach to treatment is intended to correct all of the
primary adverse consequences of atrial flutter and AF
1
:
—Irregularly irregular heartbeat with variable ventricular response
—The hemodynamic problems due to the loss of atrioventricular synchrony
—The risk of thromboembolism
●The maze procedure rests on the following concepts:
—Suture lines cannot conduct electrical impulses at physiologic voltages
—Electrically contiguous atrial tissue is brought below a critical mass
—After a maze procedure, wavelength of reentry is too long (with a normal
effective refractory period) to permit reentry
●Despite high efficacy rates, the maze procedure is not widely used
1. Sundt TM, et al. Cardiology Clin. 1997;15:739-748.
2. Cox JL, et al. Adv Cardiac Surg. 1995;6:1-67.
 

6. 6
Renewed Interest in the Maze Procedure
●New interest in the maze procedure can be partly attributed to recent
improvements in minimally invasive technology, such as thoracoscopic
epicardial microwave, RF ablation by mini-thoracotomy, cryothermy,
and ultrasound
●Another factor is the finding that with ablation in the left atrium only, it
may be possible to achieve results comparable to those of a biatrial
maze procedure

7. 7
The Cox Maze III Procedure
●The Cox maze III procedure has been used since 1992
1,2
●The maze III procedure was improved by the elimination of surgical incisions
through Bachman’s bundle and the more cephalad portion of the atrial
pacemaker complex
2
●The procedure employs a median
sternotomy technique regardless of
concomitant cardiac surgeries
1
●The typical atrial lesions of earlier
versions of the maze procedure were
supplemented by linear cryolesions
1
●The maze III procedure has evolved
and can be performed on a beating heart
1
1. Cox JL, et al. Adv Cardiac Surg. 1995;6:1-67.
2. Sundt TM, et al. Cardiol Clin. 1997;15:739-748.
Maze III procedure, with septal incision placed
posterior to the orifice of the superior vena cava.
Adapted from Cox JL, et al. Adv Cardiac Surg. 1995;6:1-
67.

8. 8
Efficacy of the Maze III Procedure
Cleveland Clinic, 1991-1999
(N =100): Clinical Outcomes of the
Maze Procedure
1
30-day mortality
Late mortality
Normal sinus rhythm
Perioperative AF
Perioperative
pacemaker
Late AF ablation
1%
5%
90.4%
33%
6%
5%
LDS Hospital, 1993-1999: Distribution of
Postoperative Rhythm
2
At Discharge
(N = 99)
At 1999 Follow-up
(N = 95)
Sinus
Junctional
AF
Atrial flutter
Paced
SSS
CHB
73
10
10
2
0
4
83
0
1
1
6
4
SSS = sick sinus syndrome; CHB = complete heart block.
1. McCarthy PM, et al. Semin Thorac Cardiovasc Surg. 2000;12:25-29.
2. Arcidi JM, et al. Semin Thorac Cardiovasc Surg. 2000;12:38-43.

9. 9
Safety of the Maze III Procedure
●LDS Hospital Study
1
—The postoperative course of patients undergoing the maze III procedure was
comparable to that of patients undergoing other, routine cardiac procedures
—No postoperative mortality
—Complications more frequent in patients undergoing the maze III procedure in
addition to other cardiac surgery
●AF common early in the postoperative phase but usually subsides
1,2
●Fluid retention in some patients early in the postoperative period;
easily controlled by medication
2
●Maze III lengthens the cardiopulmonary bypass procedure, and
exposure and bleeding of left atrial suture lines are a potential hazard
3
1. Arcidi JM, Jr, et al. Semin Thorac Cardiovasc Surg. 2000;12:38-43.
2. McCarthy PM, et al. Semin Thorac Cardiovasc Surg. 2000;12:25-29.
3. Schaff HV, et al. Semin Thorac Cardiovasc Surg. 2000;12:30-37.

10. 10
New Approaches to Surgical Ablation
●The maze III procedure has
become better circumscribed
anatomically, especially through
the successful isolation of the
pulmonary veins
1
and the
increased importance of the left
atrium
1

●Recent modifications of the maze
procedure have enabled minimally
invasive techniques using
cryoablation and RF, laser,
ultrasound, and microwave
energy
1
1. Falk RH. N Engl J Med. 2001;344:1067-1078.
2. Adapted from Rayburn ST III. http://www.ctsnet.org/sections/clinicalresources/adultcardiac/rayburn.htm. Accessed July 12, 2007. Reproduced
with the permission of CTSNet, Inc.
Isolation of the left pulmonary vein.
2

11. 11
Surgical Ablation and Lesion Sets
●Lesion sets are now made with the new surgical ablation techniques,
especially microwave, RF, and cryothermy
●Lesion sets less extensive than those of the maze III procedure,
focusing on the isolation of the pulmonary veins and the left atrium,
have been used in several recent studies
1-3
●The mode of application (eg, endocardial or epicardial), direction, and
type of maze lines have been altered1 to reduce procedural
complexity and duration and patient risk
1. Pasic M, et al. Ann Thorac Surg. 2001;72:1484-1490.
2. Sie HT, et al. Eur J Cardiothorac Surg. 2001;19:443-447.
3. Kress DC, et al. Ann Thorac Surg. 2002;73:1160-1168

12. 12
Maze III and the Berlin Modification
Adapted from Pasic M, et al. Ann Thorac Surg. 2001;72:1484-1490.
The left atrial part of the standard Cox maze III
procedure includes excision of the left atrial
appendage, multiple incisions with isolation of the
pulmonary veins, consecutive continuous sutures
of the left atrial incisions, and cryoablation of the
dissected coronary sinus and mitral annulus.
In the Berlin modification, the incisions and
sutures of the standard maze technique are
replaced by RF ablation lines (dashed lines). The
line directions are slightly changed. The right and
left pulmonary veins are isolated separately using
2 ablation lines instead of 1 encircling line as in
the standard maze procedure.

13. 13
Efficacy of Radiofrequency Ablation
●RF ablation has 70% to 80% efficacy overall
1-2
●RF ablation instruments include bipolar and cooled-tip as well as
monopolar devices
●RF has been widely used for the modified, less invasive maze III
procedures
3
●In one study, immediate recovery of left atrial function was seen in
most patients after RF ablation for chronic AF
3
●RF is a time-saving, bloodless procedure that may be as efficacious
as cryoablation or conventional surgery
4
1. Pasic M, et al. Ann Thorac Surg. 2001;72:1484-1490.
2. Scherer M, et al. Thorac Cardiovasc Surg. 2006;54:34-38.
3. Sie HT, et al. Eur J Cardiothorac Surg. 2001;19:443-447.
4. Mantovan R, et al. J Cardiovasc Electrophysiol. 2003;14:1289-1295.
 

14. 14
Efficacy of RF Ablation (Cont’d)
●Bipolar RF ablation in one study had a
91% success rate in eliminating AF
1
●Bipolar RF affords short ablation times
and reliably creates transmural lesions
with permanent conduction block
1
●Bipolar RF was deemed a comparatively
simple technique that could be widely
used with consistent results
1
●In a study using a cooled-tip device, RF
ablation had a 90.3% success rate in
restoring atrial contractile function
2
●Atrial transport function can be restored
in 70% to 100% of patients
3

1. Melby SJ, et al. J Cardiovasc Surg (Torino). 2006;47:705-710.
2. Abreu Filho CA, et al. Circulation. 2005;112(suppl):I20-25.
3. Deneke T, et al. Eur Heart J. 2002;23:558-566.
 

15. 15
Safety of RF Ablation
●The increased safety of surgical ablation with RF, including bipolar and
cool-tip techniques, is due to the decreased duration of surgery
1-5
●In addition, intraoperative RF ablation can eliminate AF without a
substantial increase in the use of the aortic cross-clamp
1
●In bipolar RF ablation, injury is confined to the tissue within the clamp
3

1. Pasic M, et al. Ann Thorac Surg. 2001;72:1484-1490.
2. Sie HT, et al. Eur J Cardiothorac Surg. 2001;19:443-447.
3. Melby SJ, et al. J Cardiovasc Surg (Torino). 2006;47:705-710.
4. Mokadam NA, et al. Ann Thorac Surg. 2004;78:1665-1670.
5. Abreu Filho CA, et al. Circulation. 2005;112(suppl):I20-25

16. 16
Efficacy and Safety of Bipolar RF Combined With
Cryoablation
●The use of a bipolar RF device in conjunction with a cryoprobe
demonstrated good safety and efficacy in a preliminary study
●The combined bipolar RF device and cryoprobe were found to be
superior to monopolar RF ablation
—Previous concerns over transmurality, collateral damage to tissues, and tissue
perforation within the esophagus were shown to be unfounded
—Bipolar RF ablation was found to be superior to monopolar RF ablation in both
safety and transmurality
●In cases in which the full maze procedure could not be carried out with
the RF probe, the cryoprobe performed well
Sternik L, et al. J Heart Valve Dis. 2006;15:664-670.

17. 17
Efficacy and Safety of Microwave Surgical Ablation
●Microwave ablation in an epicardial approach
was as effective as cryoablation in one study
1
●Microwave ablation reduced operative and
aortic clamp time
1
●Use of microwave energy produced complete
transmural lesions with very localized tissue
damage, ease of creating linear lesions, and
the ability to attain total epicardial ablation
1
●The recovery of sinus rhythm was good in most
patients, and there was no mortality, stroke, or
myocardial infarction
1
●Excess microwave energy is absorbed by
blood rather than adjacent structures, and
esophageal perforation is rare
2
1. Lee SK, et al. J Korean Med Sci. 2005;20:727-731.
2. Molloy TA. Ann Thor Surg. 2005;79:2115-2118.

18. 18
Efficacy and Safety of Ultrasound Ablation
●High-intensity focused ultrasound (HIFU)
was performed epicardially on the beating
heart. The cure rate among patients with
permanent AF was reported to be 80%
●No early or late complications or death
were related to ablation with HIFU. The
operative mortality rate was 3.8%
●The advantages of HIFU seem consistent
with other new techniques
●HIFU was deemed a superior ablation
procedure because it is less invasive
(no cardiopulmonary bypass or aortic
cross-clamping)
Ninet J, et al. J Thorac Cardiovasc Surg. 2005;130:803-809.

Ultrasound ablation system

19. 19
Minimally Invasive Surgical Ablation
●The ultimate goal in treating AF is the creation of minimally invasive
procedures that produce the same favorable results as more extensive
procedures
●Microwave and RF methodologies and cryothermy offer less extensive
methods for treating AF than those used in the original maze procedure
●Microwave and ultrasound ablation offer the least invasive means of
performing the maze and hybridized maze procedures
●Avoiding the use of a cardiopulmonary machine and cross-clamping is
seen as quite advantageous by most cardiac surgeons
●More studies are needed, but there seems to be an impetus toward
further development and refinement of less invasive procedures

20. 20
New Surgical Approaches and Visualization
●Minimally invasive approaches have the advantage of direct visualization of
the crucial structures in AF, namely, the left atrium and the pulmonary veins.
1

This visualization has become critical in the effective treatment of AF
●Ablation tools that facilitate the rapid creation of transmural lesions (in 10
to 20 minutes),
2
minimize damage to adjacent tissue, and render proper
assessment of transmurality are also vital to successful treatment
1
●It appears that the new ablation devices, which offer superior visualization
of crucial cardiac structures combined with other advantages, will logically
replace the older surgical techniques
●Thoracoscopic techniques with devices that provide for epicardial ablation on
a beating heart may provide the least invasive approach described thus far
3
1. Gillinov AM, McCarthy PM. Ann Thorac Surg. 2002;74:2165-2168.
2. Sie HT, et al. Eur J Cardiothorac Surg. 2001;19:443-447.
3. Saltman AE, et al. Heart Surg Forum. 2003;6:E38-41.

21. 21
Conclusions
●Over the past 10 years the surgical treatment of AF has quickly evolved, and
techniques such as bipolar RF, the cryoprobe, microwave energy, and HIFU have
been used to create atrial lesions in the endocardium, epicardium, or both
●These techniques have evolved into hybridized maze procedures. They may or may
not include the right-sided lesions of the maze III procedure
●The goal of the techniques discussed in this presentation is to create lines of intra-
atrial conduction block that will prohibit the development of macroreentrant circuits,
isolate the trigger(s) in or near the pulmonary vein, and allow the atria to resume
sinus rhythm
1
●Many of the new surgical ablation techniques accomplish all of these goals more
easily, safely, and quickly, and less invasively
●Better clinical definitions of success are required to comparatively assess the
different technologies and procedures
1. Ninet J, et al. J Thorac Cardiovasc Surg. 2005;130:803-809.