Hybrid atrial fibrillation ablation

Hybrid atrial fibrillation ablation
Presenter
Dr Praveen Gupta
Moderator
Dr Raja selvaraj
02.11.2017
JIPMER
Pondicherry
India
1

Introduction
 Atrial fibrillation (AF) is the most common cardiac arrhythmia with a lifetime risk of 25 %
for people aged above 40 years.
 Due to an aging population, the incidence is increasing even further
 Total number of annual AF ablation in the United States exceeds 100,000.
2

Introduction
 Secondary to negative hemodynamic effects, AF carries significant morbidity and mortality;
stroke is the most feared complication with a fivefold increased risk
 Treatment of AF is important
 Initially, rhythm control treatment of AF limited to a DC shock or taking quinidine, and
digitalis was recommended for rate control
 In 1982, the first catheter ablation (CA) aimed at achieving rate control by ablation of the
atrioventricular junction
4

Introduction
 First successful cut and sew surgical
treatment (cut and sew Maze
procedure) was performed in 1987 by
Dr. Cox.
5
Dr. James L. Cox, cardiac surgeon and emeritus chief of
the Division of Cardiothoracic Surgery at Washington
University

Cox maze procedure
6
 Designed to block the multiple
macroreentrant circuits
 The final iteration of his cut-and-
sew technique, termed the CMP-III,
 Highly efficacious, with
 97% freedom from symptomatic
AF,
 Gold standard for the surgical
therapy of AF for >10 years
The original cut-and-sew Cox-Maze procedure III

Cox maze procedure
 The development of alternative energy sources has enabled surgeons to create lines of
ablation to replace most incisions of the original CMP-III, which shortened and simplified the
procedure
 Bipolar radiofrequency energy was able to create reliable transmural lines of ablation while
minimizing the risk of collateral damage to the surrounding tissue
 In 2002, CMP-IV, which used bipolar radiofrequency and cryoenergy to replace most of the
original incisions
 Cox‐Maze‐IV surgery, which is performed on cardiopulmonary bypass and uses a
combination of radiofrequency ablation, cryoablation, and surgical incisions
7

Incision in cox maze IV procedure (Box lesion in LA as
compared to non box lesion in cox III)
8
Voeller RK, Bailey MS, Zierer A, Lall SC, Sakamoto SI, Aubuchon K, Lawton JS, Moazami N, Huddleston CB,
Munfakh NA, Moon MR. Isolating the entire posterior left atrium improves surgical outcomes after the Cox maze
procedure. The Journal of thoracic and cardiovascular surgery. 2008 Apr 30;135(4):870-7.

Cox-maze procedure
 The next step in the evolution of the procedure was the replacement of the cryoablation
lesions and the surgical incisions with radiofrequency ablation alone.
 This step obviates the need for cardiopulmonary bypass and created an epicardial‐only
technique
9

Cox-maze procedure
 Evolution of epicardial ablation tools created the ability to access portions of the
left atrium either through mini‐thoracotomies or using thoracoscopic tools.
 Obtaining safe access around the pulmonary veins.
 Bipolar clamp‐like device to ablate around the antral portion of the left atrium just
proximal to the pulmonary veins on each side.
 Completion of the box lesion requires epicardial‐only tool to create the roof and
floor lines
10

Results of a Thoracoscopic Based Surgical Ablation Procedure
 Freedom from AF at 1 year 70% to 87% with paroxysmal AF
 Persistent AF, 39% to 62% off anti‐arrhythmic drugs at 6 month
 Long‐standing persistent AF, epicardial‐only minimally invasive surgical atrial
fibrillation has modest efficacy
11

Limitaion of epicardial radiofrequency ablation
 Why the epicardial radiofrequency limited in terms of energy and heat transfer
 Excessive heating of the epicardial layers increases tissue impedance reducing current
delivery. Thus repeat applications of energy may have diminishing returns.
 Excessive heating at epicardial surface occur while deeper layers of tissue are cooled by the
endocardial intracavitary blood flow
12

Limitation of surgical procedure for AF ablation
 Despite the excellent results of open SA of AF, its widespread use has been limited
by its morbidity, especially for stand-alone surgical procedures.
 Ablation lines from alternate energy sources to replace many of the surgical
incisions in the cut and sew maze led to a thoracoscopic, minimally invasive, off-
pump beating heart approach.
 Minimally invasive thoracoscopic surgery may improve on the results of AF
catheter ablation but may not be as effective as open surgery because of limitations
in creating transmural lesions in roof and floor of the left atrial posterior wall in
some patients.
13
Khoynezhad A, Ellenbogen KA, Al-Atassi T, Wang PJ, Kasirajan V, Wang X, Edgerton JR. Hybrid Atrial
Fibrillation Ablation: Current Status and a Look Ahead. Circulation: Arrhythmia and Electrophysiology.
2017 Oct 1;10(10):e005263.

Introduction
• 1998, Haissaguerre et al.
recognized pulmonary vein (PV)
foci as initiators of AF, which
currently forms the cornerstone
of most interventional treatments
for AF
14

Limitation of RF ablation
 Higher AF recurrence rates, especially in persistent and long-standing
persistent AF
17

Rationale for a Hybrid Surgical and Catheter Ablation
Approach
• Because thoracoscopic SA and CA interventions may lead to incomplete isolation of the PVs
and the posterior wall of left atrium, a hybrid option combining these 2 techniques was
developed.
• Combining endocardial ablation with epicardial ablation may have advantages in creating
transmural lesions, particularly in areas of increased tissue thickness or in patients with scar
or extremely large atria.
• Assessment of gaps and the ability to ablate these gaps.
• Create lesions that are surgically difficult or impossible from the epicardial surface (
cavotricuspid isthmus line and completion of lines to the mitral annulus)
18
2017 Oct 1;10(10):e005263.

Concept
• Hybrid AF ablation consists of subsets of the CM IV lesion set applied epicardially via
minimally invasive thorascopically based approach followed by CA, which treats gaps in
ablation lesions and any additional atrial reentrant circuits.
• Represents a collaborative approach between the cardiothoracic surgeon and
electrophysiologist (EP) utilizing the strengths of both techniques in order to achieve
outcomes that maximize success rates and minimize procedural morbidities
• There are variations about the energy sources used, the surgical approach, the timing of
the surgical and catheter components, the ablation lesion set applied, management of
the LAA, and the medical management of these patients
19
2017 Oct 1;10(10):e005263.

Hybrid atrial fibrillation procedure
 First procedures did not use catheter ablation but used electrophysiological testing
to document conduction block at the time of surgical ablation
 Subsequently, incorporated both an epicardial surgical ablation stage and an
endocardial catheter ablation stage
Driver K, Mangrum JM. Hybrid approaches in atrial fibrillation ablation: why, where and who?. Journal of thoracic
disease. 2015 Feb;7(2):159. 20

Components of hybrid AF ablation
• Primary components are PVI with LA linear lesions, and endocardial confirmation
and additional lesions to assure conduction block
• Adjunctive measures include targeting GPs and the ligament of Marshall, complete
LA “box lesion”, RA linear lesions, endocardial cavo-tricuspid ablation, and LA
appendage occlusion
disease. 2015 Feb;7(2):159. 21

disease. 2015 Feb;7(2):159. 23

Timing of the Stages of the Hybrid Procedure
 Simultaneous, convergent epicardial and endocardial ablation,
 Staged approach with an initial surgical procedure followed by
a planned catheter procedure
disease. 2015 Feb;7(2):159. 24

Simultaneous or convergent approach
 Involves a laparoscopic approach crossing the diaphragm into the epicardial space
via pericardial window
 Linear epicardial ablation to the posterior LA by unipolar RF, isolating the PVs
along with inferior and superior lines on the posterior LA wall
 Lines were completed with RF catheter ablation at the antral level of the superior
left and superior and inferior right PVs.
 Only one procedure is necessary
 Allows for immediate endocardial confirmation of isolation, such that additional
epicardial ablation can be performed
disease. 2015 Feb;7(2):159. 25

Simultaneous or convergent approach
 Complications included several mortalities from atrio-esophageal fistulae
 Stroke, bleeding, and pericardial effusion
 Serious adverse complication (10%)
 Time-consuming
 Requires coordination of a surgical and procedural electrophysiological team
 Periprocedural anticoagulation can be challenging
 Adapting the procedure space is difficult to optimize conditions for both the
surgical and EP operators
disease. 2015 Feb;7(2):159. 26

Staged hybrid procedure
 Initial thoracoscopic epicardial ablation then catheter ablation after days to weeks
 Epicardial ablation targets PVI as well as additional empiric substrate ablation
 Allows optimal conditions and convenience for both the surgical and EP teams
 Allows for completion of epicardial lesions at the time of catheter ablation
disease. 2015 Feb;7(2):159. 27

Staged procedure
 Enables identification of areas of early reconnection which has been shown to be a
major reason for failure of catheter ablation.
 More compatible with advanced invasive substrate mapping, including mapping
and ablation of rotors which have been shown to be a major contributor to
persistent AF
disease. 2015 Feb;7(2):159. 28

disease. 2015 Feb;7(2):159. 29

Conditional hybrid procedure
 Epicardial ablation is performed with catheter ablation reserved only for patients
with recurrent AF
 This possibility was raised by the Brescia group
 Monopolar RF system with a suction mechanism to augment tissue contact was
used to isolate the PVs en bloc with the entire posterior wall
disease. 2015 Feb;7(2):159. 30

Conditional hybrid procedure
 Block was demonstrated at the time of surgical ablation with pacing from
catheters inside the box lesion from the posterior epicardial surface and outside
from the coronary sinus
 Bidirectional block was present at the conclusion of the epicardial ablation and
remained at the outset of the catheter procedure at least 30 days later in 91%; as a
result in nearly 30% of patients additional endocardial ablation was not performed
disease. 2015 Feb;7(2):159. 31

Concerns of hybrid procedure
 Electroanatomic mapping cannot be performed from the epicardial surface
 If performed as a staged approach following epicardial ablation, electroanatomic
mapping is unable to guide epicardial ablation, including identifying additional
triggers or substrate which may be more effectively targeted epicardially
 If substrate modification in addition to PVI is performed, including additional
linear lesions, electroanatomic confirmation of block cannot be demonstrated at the
time of surgical ablation
disease. 2015 Feb;7(2):159. 32

Limitation of hybrid procedure
 Epicardial linear lesions fail to achieve bidirectional block in 23% of patients
 Incomplete linear ablation predispose patients to risks of atrial tachycardia and flutter.
 Managing appropriate anticoagulation is challenge
disease. 2015 Feb;7(2):159. 33

 Risks of both thoracoscopic and transvenous access
 Thoracic injury
 Pericarditis
 Bleeding and vascular injury
 Tamponade
 With staged approaches, additional time and costs, multiple procedures and convalescence
 Epicardial surface have coronary arterial and venous circulation.
 Epicardial fat does not allow RF energy to penetrate adipose tissue
disease. 2015 Feb;7(2):159. 34

 Data from randomized trials are lacking
 Reporting bias among published studies
 Large studies of hybrid AF ablation, including the staged deep study, FAST-II, and SCALA-
success have not yet been published
disease. 2015 Feb;7(2):159. 35

Trial on hybrid atrial fibrillation procedure
disease. 2015 Feb;7(2):159. 36

Results of the Hybrid Procedure
 Most studies report only 6‐months or 1‐year follow‐up
 Ideal goal of hybrid procedure should be freedom from AF in 3 to 5 years
 Some studies report conversion to sternotomy, tamponade, hemothorax, pneumothorax,
pleural bleeding, and bleeding as complications
37

Hybrid Procedure (Endo/Epicardial) versus Standard Manual Ablation in Patients
Undergoing Ablation of Longstanding Persistent Atrial Fibrillation: Results from a Single
Center.
• Only prospective study comparing a hybrid AF ablation approach (24 patients) to an
endocardial-only ablation (35 patients).
• Only study to highlight their high-complication rates and lower efficacy of a hybrid approach
• Hybrid group underwent SA through pericardioscopic approach followed immediately by CA
• Used a unipolar radiofrequency device to perform PVI, posterior box, ablate the ligament of
Marshall, and the lateral right atrium
• Endocardial portion entailed verification and completion of epicardial lines, line to the
coronary sinus, isolation of the LAA, and ablation of complex fractionated atrial
electrograms.
38J Cardiovasc Electrophysiol. 2016 May;27(5):524-30. doi: 10.1111/jce.12926. Epub 2016 Feb 25.

Hybrid Procedure (Endo/Epicardial) versus Standard Manual Ablation in Patients
Undergoing Ablation of Longstanding Persistent Atrial Fibrillation: Results from a Single
Center.
 At 12-month follow-up, hybrid group had lower arrhythmia-free survival (24% versus 63%;
P<0.001).
 At 24 months, hybrid group continued to have inferior results (19% versus 54%; P>0.001).
 Complication rates were significantly higher in the hybrid group (21% versus 3%; P=0.036),
including 3 deaths, 1 tamponade, and 1 phrenic nerve palsy in the hybrid group compared
with 1 tamponade in the CA group
 Rate of mortality because of atrioesophageal fistula and the sudden deaths was unacceptable.
 May be due to unipolar radiofrequency and the approach (pericardioscopic and concomitant
CA)
39
2017 Oct 1;10(10):e005263.

Prospective Multicenter Clinical Trials of Hybrid AF Ablation
 There are currently 2 FDA-approved industry-sponsored clinical trials involving
thoracoscopic and pericardioscopic approaches
40
2017 Oct 1;10(10):e005263.

CONVERGE trial (Convergence of Epicardial and Endocardial
Radiofrequency Ablation for the Treatment of Symptomatic
Persistent AF)
 Multicenter, prospective, open-label, randomized 2:1 (convergent procedure versus
endocardial catheter ablation) pivotal study
 The hybrid portion is completed under general anesthesia: using a pericardioscopic approach,
the posterior left atrial wall is ablated using the unipolar radiofrequency device.
 Endocardial procedure (PVI and cavotricuspid lesion) is subsequently performed with
irrigated unipolar radiofrequency.
 Primary efficacy end point is freedom from AF, atrial tachycardia, and atrial flutter without
class I and III AADs through the 12-month postprocedure follow-up visit.
 Will enroll ≤153 subjects in ≤17 sites, and to date, there have been 51 patients enrolled
41
2017 Oct 1;10(10):e005263.

DEEP approach (dual epicardial and endocardial procedure)
 Multicenter industry-sponsored clinical trial for persistent or long-standing persistent
AF.
 Staged hybrid prospective, single-arm, pivotal study
 Totally thoracoscopic procedure is performed from 2 pleural cavities, and the LAA is
excluded
 Following lesions are performed using bipolar radiofrequency: right and left antral
lesions (isolating both PVs), left atrial roof and floor lesions, and a lesion at the base of
the LAA
 After 90 days, the endocardial mapping and ablation procedure uses a commercially
available radiofrequency-based, irrigated, power-controlled ablation system to ablate any
gaps in the previous lesions and to complete a cavotricuspid isthmus lesion.
42
2017 Oct 1;10(10):e005263.

Prospective Multicenter Clinical Trials of Hybrid AF Ablation
 The primary outcome end point is freedom from any AF, atrial flutter, or atrial tachycardia through
the 12-month follow-up visit in the absence of class I or III AADs (with the exception of any
previously failed AADs at the same or lower doses).
 Similar to the CONVERGE trial, the rhythm status used for evaluation of this end point will be
derived from regularly scheduled monitoring (ie, Holter, Zio-Patch, or 30-second 12-lead ECG) and
any symptom-driven monitoring that is performed.
 The primary safety end point is a composite end point consisting of serious adverse events within 30
days of the epicardial SA procedure, or within 7 days of the index endocardial procedure, or within 7
days after a repeat endocardial procedure within the blanking period. The DEEP trial will enroll
≤220 subjects in ≤25 sites.
43
2017 Oct 1;10(10):e005263.

Take home message
 Hybrid epicardial and endocardial ablation is promising.
 Hybrid ablation may be considered in patients with persistent and long-standing
persistent AF
 Such situations include patients with advanced LA structural remodeling such as in
valvular AF, patients following atrial septal defect closure, or patients with challenging
venous access.
 Hybrid ablation considered in patients with persistent AF who have failed catheter
ablation particularly those in whom endocardial PVI has failed because of risk to
surrounding structures including phrenic nerve or esophageal injury
 Study of techniques and patient selection will be necessary to optimize outcomes
44

Hybrid atrial fibrillation ablation

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