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Despite this, there are certain conditions in which we would
advocate for repair in severe IMR. A restrictive annuloplasty and
‘le ventricular’ procedure such as papillary muscle approximation should be considered when the following criteria exist:
• Reversible inferior-posterior-lateral ischemia—minimal scar
• Good bypass target in the PDA and Circumex territory
• Acceptable LV dysfunction (LVEF ≥ 35%)
• Non-severely dilated ventricle
• LVEDd < 65 mm
■
LVESd < 55 mm
■
LVESVI < 70 ml/m2
• Papillary Muscle Approximation (PMA) recommended as an ad-
juvant ‘Ventricular Operation’
■
Restrictive annuloplasty is insucient, but necessary
Percutaneous mitral valverepair
Many patients with moderate or severe IMR are high- risk surgical
candidates. is, combined with the predicted rise in the ageing
population and prevalence of heart failure, underscores the impetus
to develop less invasive approaches to treating mitral valve disease.
Several companies have developed percutaneous devices for mitral
repair. Percutaneous approaches can be grouped by their site of ac-
Several important dierences between the COAPT and MITRAFR studies may give insight into the discrepant ndings. e baseline
echocardiographic le ventricular end- diastolic volumes were substantially higher in the COAPT trial., ere was also a marked
dierence in follow- up data available at 1- year: COAPT 97.7% in
the device group and 94.2% in the control group compared to 54.6%
and 51.3%, respectively, in the MITRA- FR study. MITRA- FR indeed
had a signicant amount of missing echocardiographic, outcomes,
functional status, and quality- of- life follow- up data. e diering
results of these randomized studies challenge uniform conclusions.
Nonetheless, the studies may have looked at dierent populations of
patients and most clinicians seem to be guided in practice more by
the COAPT results.
Another percutaneous approach involves implantation of devices
within the coronary sinus in order to push the posterior annulus anteriorly and thus reduce the anterior– posterior dimension of the mitral annulus, improve leaet coaptation, and reduce MR. Potential
technical issues with the coronary sinus approach include pinching
of the circumex artery as well as coronary sinus thrombosis, occlusion, erosion, or perforation. e coronary sinus also does not overlie
the annulus but rather is located at a 6– 12mm distance from it. In the
setting of mitral annular calcication, it is unclear how eectively this
technique would be able to displace the posterior annulus.
tion, for example, those addressing the leaets and those addressing
the annulus. One technique entails leaet plication or an edge- toedge repair, and is based on the concept of the Aleri stitch which
Conclusion
brings the anterior and posterior leaets together thus creating a
double orice. e MitraClip® (Abbott Vascular, Santa Clara, CA,
USA) utilizes this technique via a transseptal approach and has been
mostly described in degenerative MR but may have utility in IMR as
well. Five- year results from the Endovascular Valve Edge- to- Edge
Repair Study II (EVEREST II) which compared the MitraClip® with
surgery demonstrated a lower freedom from death, surgery or 3+ or
4+ MR in the MitraClip® group at 44.2% versus 64.3% (P=0.01).
Rates of surgery and moderate or severe MR beyond 6months were
comparable and 5- year mortality were comparable between the
groups.
ere are two more recent trials evaluating the ecacy of
MitraClip®., e Cardiovascular Outcomes Assessment of the
MitraClip® Percutaneous erapy for Heart Failure Patients with
Functional Mitral Regurgitation (COAPT) trial, randomized 302
patients to the device arm and 312 patients to the control arm.
Patients were eligible if they had symptomatic heart failure despite
medical therapy and moderate- to- severe or severe MR. e annualized rate of all hospitalization for heart failure within 24months
was signicantly reduced in the MitraClip® group, as was death from
any cause within 24months. Another trial was the Percutaneous
Repair with the MitraClip® Device for Severe Functional/ Secondary
With the ageing population and expected increase in the prevalence
of heart failure in the United States, the number of patients with IMR
will likely increase. Numerous studies have demonstrated that surgical correction of the mitral valve concomitant with CABG can be
safely performed with acceptable operative mortality and morbidity
in the setting of moderate or severe IMR. Delineating the symptomatic, remodelling, and survival benets of surgery in these settings
are prudent. Randomized trials have now evaluated the addition of
mitral valve repair to CABG in moderate IMR and also mitral valve
repair versus replacement concomitant with CABG in severe IMR.
e moderate IMR trials have shown some diering results but have
provided insight into a selection of patients for mitral valve repair.
Both the 1- and 2- year outcomes from the CTSN trial for severe
IMR advocate for the use of mitral valve replacement mainly due
to its substantially lower rate of recurrent moderate or severe mitral
valve regurgitation. e maturation and evolution of novel percutaneous technology will likely provide alternative and less invasive
approaches to addressing mitral valve disease in this population. As
data accumulates and further trials are conducted, the future of IMR
treatment will hopefully be met with renements that will lead to
continually better outcomes.
Mitral Regurgitation (MITRA- FR) trial. Patients were enrolled
if they had severe secondary MR, le ventricular ejection fraction of 15– 40%, and symptomatic heart failure. In total, 152 patients were randomized to MitraClip® and 152 patients to medical
therapy alone. At 12months, the composite outcome of death from
any cause or unplanned hospitalization for heart failure was comparable between groups. When these outcomes were individually
assessed, there was again no dierence between the MitraClip® and
control cohorts.
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Benedetto U, etal. 2018 ESC/ EACTS Guidelines on myocardial
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Khonsari S, etal. Randomized trial comparing partial versus
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2002;123(4):707– 14.
8. Aklog L, Filsou F, Flores KQ, Chen RH, Cohn LH, Nathan
NS, etal. Does coronary artery bypass graing alone correct
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valve repair versus revascularization alone in the treatment of ischemic
mitral regurgitation. Circulation. 2006;114(1, Suppl):I499– 503.
10. Gillinov AM, Wierup PN, Blackstone EH, Bishay ES, Cosgrove DM,
White J, etal. Is repair preferable to replacement for ischemic mitral
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11. Schroder JN, Williams ML, Hata JA, Muhlbaier LH,
Swaminathan M, Mathew JP, etal. Impact of mitral valve
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12. Chan KM, Punjabi PP, Flather M, Wage R, Symmonds K, Roussin
I, etal. Coronary artery bypass surgery with or without mitral
valve annuloplasty in moderate functional ischemic mitral
regurgitation:nal results of the Randomized Ischemic Mitral
Evaluation (RIME) trial. Circulation. 2012;126(21):2502– 10.
13. Fattouch K, Guccione F, Sampognaro R, Panzarella G, Corrado E,
Navarra E, etal. POINT:ecacy of adding mitral valve restrictive
annuloplasty to coronary artery bypass graing in patients with
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Moskowitz AJ, etal. Two- year outcomes of surgical treatment
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M, etal. Predictors of improvement of unrepaired moderate
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66
Combined coronary artery bypass graing
and aortic valvereplacement
Christopher Lau and Leonard N. Girardi
Introduction
Aortic valve replacement (AVR) and/ or coronary artery bypass
graing (CABG) have become the most common cardiac procedures as the population ages and life expectancy increases. In isolation, both CABG and AVR are performed with excellent outcomes
throughout the world with operative mortalities of 1– 2%. Both
procedures have seen signicant advances in recent years. e combination of an aortic valve procedure and CABG adds increased
complexity and risk, which must be accounted for during operative
planning in order to mitigate as much of the increased risk as possible. Improvements in postoperative care, myocardial protection,
and operative techniques for combined CABG and AVR have resulted in an operative mortality of 0.8– 6.4% in recent series.–
Technological advances have resulted in a major push towards
minimally invasive techniques, including transcatheter AVR and
percutaneous coronary interventions utilizing ever- improving devices. Surgeons are increasingly faced with patients of increasing
complexity and a higher risk prole as the more straightforward
cases of isolated valvular or coronary disease are moving towards
transcatheter techniques. While transcatheter AVR is increasingly
being used to treat moderate to high- risk patients and percutaneous
coronary intervention is being used for increasingly complex lesions, including le main disease, combined signicant aortic valve
disease and coronary artery disease (CAD) remains best treated
with standard open CABG and AVR, except in the highest risk cohorts. ese more complex patients require a thoughtful approach
to optimize their outcomes.
Combined cases lead to lengthier operations with longer myocardial ischaemia and cardiopulmonary bypass times. Careful operative planning can help to improve the ow of the procedure and
reduce the burden of ischaemic stunning that may occur in the early
postoperative period. Myocardial protection is of paramount importance in achieving optimal results when long ischaemic times are
expected. oughtful preoperative assessment of the contribution of
each valvular or coronary lesion to myocardial function, as well as
the expected improvement in function aer repair or bypass of each
lesion, aid in stratifying the risk to the patient and in planning the
degree of inotropic and mechanical support that may be necessary
when separating from cardiopulmonary bypass and in the postoperative period.
Preoperativeevaluation
Clinical evaluation includes the routine history and physical examination, laboratory tests, echocardiography, and coronary angiography. Consideration of the ndings on these examinations helps
determine whether the CAD or valvular disease is the primary lesion and the degree of heart failure that the patient is experiencing.
Accurate risk stratication assists the surgeon in discussion with the
patient and family about risks and expectations in the postoperative
period.
Echocardiography is a mandatory preoperative test that provides
a wealth of information when formulating a plan. Assessment of
ventricular function is of paramount importance in determining
risk. Wall motion abnormalities can indicate the areas of ischaemic
myocardium and distinguish areas of reversible or irreversible myocardial dysfunction. is, combined with coronary angiography,
gives an indication of how much hibernating myocardium can be
recruited with coronary revascularization. Echocardiography also
determines the type and severity of the valvular disease. Insight
into the type of ventricular dysfunction, such as a dilated cardiomyopathy due to severe aortic insuciency or a non- compliant,
hypertrophied, hyperdynamic ventricle due to severe aortic stenosis
(AS), is necessary to form a corresponding intra- and postoperative
management plan. In borderline cases where the signicance of the
valvular lesions is unclear, such as with low- gradient, low- ejection
fraction AS, stress echocardiography may be useful to elicit haemodynamic changes that conrm the severity of the valve disease and
the potential for ventricular recovery aer surgery.
In patients with severely compromised ventricular function, an
assessment of myocardial viability can be helpful both for estimating
the expected degree of improvement in ventricular function aer
revascularization and for determining whether certain coronary
distributions are worth spending the extra cross- clamp time to
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bypass. Nuclear viability studies and positron emission tomography
detect regions of viable myocardium with reversible ischaemia as
opposed to irreversible scar tissue. Cardiac magnetic resonance imaging provides even higher resolution. It not only provides viability
information but also dierentiates areas with subendocardial infarction from transmural infarction and scar. Areas with no viability
done with low risk. Additionally, those with AI due to aortic dilatation are more likely to progress than those with AI due to leaet
abnormalities, and greater consideration should be given to performing an AVR. e recent widespread availability of transcatheter
AVR may encourage isolated CABG for high- risk patients with
CAD and moderate aortic valvular disease.
should not be bypassed and this may preclude some patients from
having surgery at all.
In clinical practice, oen one lesion is the dominant lesion
Surgicalmanagement
bringing the patient to the operating room and the other lesion may
be less than severe. If both the CAD and valvular disease are severe
by criteria, then clearly a combined CABG + AVR is necessary in
order to avoid problems with separating from cardiopulmonary
bypass or postoperative low cardiac output syndrome. Oen, the
CAD may be severe with mild to moderate aortic valve disease, or
vice versa. e surgeon and consulting cardiologist must determine
whether to leave the secondary process alone or to add it to a combined valve- coronary procedure.
In patients presenting primarily for aortic valve disease, oen
CAD is found incidentally on preoperative cardiac catheterization.
e presence of CAD in patients undergoing valve surgery signicantly decreases the median survival for patients of all ages. Patients
with aortic valve disease plus CAD are more likely to have risk factors
such as advanced age, hypertension, poor ventricular function, and
greater arteriosclerotic burden. While long- term survival is poorer
in this group, likely due to the increased atherosclerotic burden, operative and short- term outcomes are not signicantly dierent between the AVR and AVR plus CABG groups., In fact, in patients
with moderate (50– 70%) to severe (>70%) CAD undergoing AVR,
if CABG is performed it confers a long- term survival advantage by
reducing 5- year mortality by more than a third, whereas omitting
CABG in a patient with CAD may result in a fourfold increase in
operative mortality.
Patients presenting primarily for CABG may have some degree
of AS or aortic insuciency (AI). e surgeon must then decide
whether an AVR should be added to the CABG, thereby increasing
operative times and risk of morbidity compared to an isolated CABG.
ose with mild AS or mild AI are unlikely to need reoperation for
AVR in the future. ose with mild to moderate AS or AI at the
time of surgery have a signicantly increased rate of aortic valve
reoperation when followed out to 6years. Focusing on the group
of patients with moderate AS, freedom from reoperative AVR at
5years is generally comparable in the CABG versus the CABG plus
AVR groups. However, those with maximum and mean aortic valve
gradients of 26mmHg and 15mmHg or greater are at increased risk
of needing reoperations. Low- risk patients with long expected survival may benet from a reduced risk of reoperation associated with
CABG plus AVR while higher- risk patients who have poor expected
mid- term survival have minimal risk of needing reoperative AVR
at 5years.
e assessment of patients undergoing CABG with moderate AI
is similar. In short- term follow- up to approximately 4years, AI is
unlikely to progress to need AVR in the early years aer CABG and
severe AI is seen in 6.9%. In patients with advanced age or poor
expected mid- term survival due to comorbidities, avoiding AVR
would be reasonable. However, in younger low- risk patients, the
natural history of AI is to progress to severe AI at a rate of 1.9% per
year and it is reasonable to perform a CABG plus AVR if it can be
Preparation and anaesthetic management follow routine principles
for cardiac surgical patients, including arterial lines, central venous
catheters, pulmonary artery catheters, and thermodilution cardiac
output monitors. In specic situations, additional monitoring may
be employed, such as continuous mixed venous oxygen saturation
or cerebral oximetry.
Due to the need for both coronary and valve work, the standard
incision is a median sternotomy. e internal thoracic artery, saphenous vein, or other bypass conduits are harvested as necessary, based
on angiographic ndings. e cardiopulmonary bypass circuit is set
up using a return cannula in the distal ascending aorta and a dual
stage venous drainage cannula in the right atrial appendage coursing
into the inferior vena cava. Acardioplegia cannula is placed in the
mid- ascending aorta, which is also used to vent the aortic root. Once
cardiopulmonary bypass is established, a le ventricular vent is routinely placed via the right superior pulmonary vein. Aretrograde
cardioplegia catheter is placed into the coronary sinus in select cases,
such as with a totally occluded le anterior descending artery. Our
preference is to rely mainly on antegrade cardioplegia, which is readministered every 20– 30 minutes, since retrograde cardioplegia
may not oer optimal right heart protection if the catheter is not perfectly positioned. Target vessels are identied and marked while the
heart is still beating. e patient is cooled to 32°C, the cardioplegia
circuit is ushed with cold blood cardioplegic solution, and the bypass conduits are prepared as necessary. Amyocardial temperature
probe is used to conrm adequate cardioplegia administration.
e aortic cross- clamp is applied with a temporary reduction in
pump ow. e technique for cardioplegia administration depends
upon the amount of AI. In cases with mild or less AI, antegrade
cardioplegia may be administered via a non- selective injection into
the root. e ventricular vent is usually sucient to prevent ventricular distension, while the mildly regurgitant valve provides adequate pressurization of the root to perfuse the coronary arteries.
With moderate or greater AI, a root injection for cardioplegia is not
possible. Instead, a transverse aortotomy is created and cardioplegia
is injected directly into the coronary ostia with handheld catheters.
In all cases, iced saline slush is used for topical cooling, taking caution to avoid placing ice on the phrenic nerve. AStyrofoam pad is
used to insulate the heart from adjacent tissues and to protect the
phrenic nerve.
If the aorta has been opened, the aortic valve can be resected at
this time to make subsequent cardioplegia injections easier. e
distal coronary anastomoses are then performed, which allows
direct access to obstructed coronary distributions for cardioplegia
through the gras during subsequent cardioplegia administration.
e internal thoracic artery anastomoses, if they are used, are also
performed and they are then occluded with bulldog clamps until the
aortic cross- clamp is released.
66 Combined coronary artery bypass grafting and aortic valvereplacement 453
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e aortic valve is resected and the annulus is debrided if this has
not yet been done. e annulus is sized appropriately and a pros-
valve function, myocardial perfusion, and ventricular function in
order to optimize short- and long- term outcomes.
thesis is chosen. e choice of prosthesis type is no dierent than
for isolated AVR. Valve sutures are placed in routine fashion along
the annulus utilizing a supra- annular technique and then passed sequentially through the valve sewing ring. At this point, it is oen
helpful to re- dose the cardioplegia because it is slightly more dicult
to give the ostial injections once the prosthetic valve is in place. e
valve is lowered into placed, conrming that there is no obstruction
of the coronary ostia, and the sutures are tied. Any gaps that may lead
to paravalvular leak are addressed with additional sutures, usually
placed by going through the prosthetic valve leaet opening. Anal
inspection of the coronary ostia is performed and the aortotomy
is closed with two layers of suture. e proximal anastomoses are
usually performed with the aortic cross- clamp on in order to avoid
clamping the aortic suture line with a side- biting cross- clamp and
risking damage to the aortic suture line. e patient is then placed
into Trendelenburg position, the heart is de- aired, and all bulldog
clamps and cross- clamps are released during a temporary reduction
in pump ow. e patient is weaned from cardiopulmonary bypass
and cannulas are removed in the standard fashion.
Postoperative management depends upon the primary pathophysiological problem. Apatient with AS, tight CAD, and normal
ventricular function will likely need minimal support due to relief of
the stenotic lesion and improvement in coronary blood ow. If AS is
associated with a severely hypertrophied ventricle or small le ventricular cavity, an inotropic agent with vasodilatory and lusitropic effect such as milrinone can be helpful in addition to volume loading.
On the other hand, a poorly functioning dilated ventricle, such as
with severe AI, may benet from adding an agent with strong inotropic eect, such as epinephrine, to improve the contractile force.
Patients with very severe le ventricular dysfunction or who require
high doses of vasopressors or inotropic agents would benet from
mechanical support, such as an intra- aortic balloon pump. Over the
rst few postoperative days, as the myocardium recovers from the
ischaemic insult and myocardial stunning, oen the intravenous
agents and mechanical support can be weaned fairly rapidly, except
for severely dysfunctional ventricles, which may take more time.
Results
Combined CABG plus AVR is reliably performed with an operative
mortality of 0.8– 6.4%.,,, As seen in publicly available databases,
such as the NewYork State Cardiac Surgery Database, the operative
mortality of CABG plus AVR (2.95%) is slightly higher than isolated
AVR (1.81%) or isolated CABG (1.56%) and the added complexity
of a combined procedure may add some risk. However, direct
comparison of isolated AVR to CABG plus AVR groups have shown
that there is no statistical dierence in operative outcomes in groups
with similar risk proles., ere is sucient evidence that omitting
a procedure when there is signicant native disease to indicate intervention leads to poorer long- term outcomes secondary to untreated
disease processes. In treating these complex patients, the surgeon
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must consider the important interactions between the eects of
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67
Coronary artery bypass graing withthe
maze procedure foratrialfibrillation
Hoda Javadikasgari and A. Marc Gillinov
Introduction
Atrial brillation (AF) is a supraventricular tachyarrhythmia with
uncoordinated and ineective atrial contraction. Characteristics
on an electrocardiogram include (1)irregular RR intervals (when
atrioventricular conduction is present), (2)absence of distinct repeating P waves, and (3)irregular atrial activity. Table 67.1 dem-
onstrates the current guidelines for classication of AF.
Haemodynamic consequences of AF result from suboptimal
ventricular rate, lack of coordinated atrial contraction, beat- tobeat variability in ventricular lling, and sympathetic activation.
e mechanisms of AF vary among aected individuals and so,
too, do clinical presentations, ranging from no symptoms to fatigue, palpitations, dyspnoea, hypotension, syncope, or heart
failure. Most notably, in patients with mitral stenosis, hypertension, hypertrophic cardiomyopathy, or restrictive cardiomyopathy,
diastolic ventricular lling is already impaired and loss of atrial
contraction caused by concomitant AF may markedly decrease
cardiac output.
In 2010, the estimated number of patients with AF worldwide was
33.5million, with higher incidence and prevalence rates in the developed world. By 2050, 12million AF patients are anticipated in
the United States alone with greater prevalence in older people and
in patients with hypertension, heart failure, coronary artery disease,
valvular heart disease, obesity, diabetes mellitus, or chronic kidney
disease. Coronary artery bypass gra (CABG) surgery is becoming
Table67.1 Definition ofatrial fibrillation
Terms Definitions
Paroxysmal AF Terminates spontaneously or with
intervention within 7days of onset
Persistent AF Continuous AF >7days
Long- standing persistent AF Continuous AF >12months
Non- valvular AF AF in the absence of rheumatic mitral
stenosis, a prosthetic heart valve, or mitral
valve repair
more common in older patients with comorbidities. It is no surprise,
therefore, that AF is common in such patients. Data from the Society
of oracic Surgeons National Database demonstrate that preoperative AF is present in 11% of patients presenting for non- emergent,
rst- time cardiac surgery with approximately 6.5% of CABG patients presenting with AF. AF is a marker of advanced cardiovascular
disease. Compared to CABG patients without AF, those with AF
have higher NewYork Heart Association functional class, more severe le ventricular dysfunction, and greater le atrial enlargement.
Preoperative AF in patients undergoing cardiac surgery procedures
is an independent risk factor for late adverse events, including cardiac
complications, stroke, other thromboembolic events, anticoagulantrelated haemorrhage, and reduced survival., Furthermore, with
successful surgical ablation, the survival of the patients with successful AF ablation can be restored to that of patients without preoperative AF. For these reasons, surgical treatment of AF should be
considered in the operative strategy in cardiac surgical patients with
pre- existing AF.
e use of surgical ablation for preoperative AF during cardiac surgery increased rapidly aer the introduction of devices to
create ablation lesion sets and the most recent American College
of Cardiology/ American Heart Association/ Heart Rhythm Society
Guidelines recommendation that AF surgical ablation procedure
is reasonable for selected patients with AF undergoing cardiac
surgery for other indications (class of recommendation IIa, level
of evidence C). Similarly, the most recent European Society of
Cardiology Guidelines also recommended maze surgery, preferably biatrial, should be considered in patients undergoing cardiac surgery to improve symptoms attributable to AF, balancing
the added risk of the procedure and the benet of rhythm control
therapy (classIIa, level of evidence A). Furthermore, the European
Society of Cardiology/ European Association for Cardio- oracic
Surgery Guidelines recommend concomitant biatrial maze or pulmonary vein isolation may be considered in asymptomatic AF
patients undergoing cardiac surgery considering patient choice,
benet, and risk, supported by an AF Heart Team (classIIb, level
of evidence C).
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Atrial fibrillation concomitant tocoronary
arterybypass
e electrophysiological underpinnings of AF have been studied for
decades and remains incompletely understood. Nevertheless, the
anatomical basis of AF is increasingly clear. It has been demonstrated
that the pulmonary veins and posterior le atrium are the critical
anatomical sites in patients with isolated AF. However, foci for AF
initiation are not always localized to the le atrium, and some patients also manifest right atrial focal or reentrant activation. Around
60% of all AF (paroxysmal AF) is caused by focal pulmonary vein
or atrial triggers and the other 40% or so of all AF (long- standing
persistent AF and permanent AF) is due to well- established selfperpetuating macro- reentrant circuits that have little or nothing
to do with these focal atrial or pulmonary vein triggers. Surgeons
deal with concomitant AF secondary to le heart problems such as
mitral valve disease, aortic valve disease, and coronary artery disease. In such patients, the mechanism of concomitant persistent
and long- standing persistent AF may not be due to pulmonary vein
triggers alone, and simple pulmonary vein isolation may not be adequate. e consensus is that all persistent and long- standing AF,
whether stand alone or concomitant, requires additional linear lesions to accompany pulmonary vein isolation in order to attain longterm freedom from AF.
Routine real- time intraoperative mapping is currently not available to guide AF ablation in cardiac surgery patients. erefore, an
anatomical approach to ablation based on our understanding of
pathophysiology and empiric results is rapidly becoming the foundation for both catheter and surgical- based ablation of AF.
e clamp includes as much le atrial tissue as possible. Again, four
parallel applications of the RF clamp are made (Fig. 67.1b) and exit
block is conrmed by pacing from the pulmonary veins.
Left atriallesions
e heart is then arrested with anterograde cardioplegia. Astandard
le atriotomy is performed anterior to the right pulmonary veins to
enable creation of successive connecting lesions between the right
and le pulmonary veins with the RF clamp. First, the inferior veins
are connected with one application of the RF clamp (Fig. 67.1c). As
with the inferior veins, the connecting lesion between the superior
pulmonary veins is created with another application of the RF clamp
(Fig. 67.1d). is completes the ‘box lesion’ in the posterior le
atrium.
e le atrial isthmus lesion is then isolated using both a bipolar
RF clamp and a cryoprobe. is is a connecting lesion from the right
inferior pulmonary vein to the P3 region of the mitral annulus. Here,
several manoeuvres should be used in creating this lesion:rst, the
retrograde catheter should not be in place; second, the RF clamp and
cryoprobe should be positioned to avoid the circumex coronary
artery, if possible; third, transmurality should be ensured by making
overlapping cryolesions from both the endocardial and epicardial
surfaces at the level of the coronary sinus.
e rst part of the lesion is created with bipolar RF with the clamp
angled towards the P3 segment of the mitral valve (Fig. 67.2a). At
the mitral annulus, the lesion is completed with a cryoprobe. e
coronary sinus and mitral annulus are ‘sandwiched’ between two
cryolesions, ensuring a transmural lesion (Fig. 67.2b). is lesion is
performed using nitrous- oxide based cryothermy at 60°C for 2 minutes. Appropriate thawing of the tissue is necessary before removing
the probe to avoid tearing the tissue. Finally, the le atriotomy is
Operativetechniques
Isolation ofpulmonaryveins
A standard median sternotomy is performed and cardiopulmonary
bypass is initiated using bicaval and ascending aortic cannulation.
Immediately before the CABG procedure, pulmonary vein isolation
is performed on the beating, decompressed heart which enables assessment of conduction block. e posterior surface of the right
pulmonary veins is bluntly dissected and a pacing probe is then
placed on the pulmonary veins. If the patient is in AF, cardioversion
is performed before attempting to assess the pacing threshold.
Beginning from the inferior veins, a bipolar radiofrequency (RF) is
positioned around the pulmonary veins. e clamp is advanced towards the le atrium, isolating as much atrial tissue as possible and
ensuring that energy is not delivered directly to the pulmonary vein
tissue to avoid pulmonary vein stenosis. Four parallel applications
of the RF clamp are made to ensure that there are no gaps in the
isolation (Fig. 67.1a). Exit block is then conrmed by pacing from
the pulmonary veins.
e heart is retracted to the right to expose the le pulmonary
veins. e ligament of Marshall is a brous band passing from the
coronary sinus to the superior pulmonary vein. e posterior surface of the le pulmonary veins is likewise dissected, including the
ligament of Marshall. e pacing threshold is established and the bipolar RF clamp is introduced around the inferior pulmonary veins.
closed with polypropylene sutures.
Right atriallesions
e right atrial lesion set includes an intercaval lesion, and two separate lesions to the tricuspid annulus. e intercaval lesion is created
between the superior vena cava and the inferior vena cava, avoiding
the sinoatrial node. e lesions to the tricuspid annulus are created
with cryotherm. Care is taken at this point to avoid contact between
the cryoprobe and the phrenic nerve (Fig. 67.3).
Left atrialappendage
e current data on le atrial occlusion at the time of concomitant
cardiac surgery reveal a lack of clear consensus because of the inconsistency of techniques used for surgical excision, the highly variable rates of successful le atrial appendage (LAA) occlusion, and
the unknown impact of LAA occlusion on future thromboembolic
events. e European guidelines recommended surgical occlusion
or exclusion of the LAA may be considered for stroke prevention in
patients with AF undergoing cardiac surgery (classIIa recommendation, level of evidence B).
In our practice, management of the LAA is mandatory and requires complete excision or exclusion of the LAA with a residual
stump less than 1cm in length. New epicardial occlusion devices enable safe, rapid, and complete LAA exclusion. If the surgeon chooses
to use sutures to exclude the LAA, endocardial exclusion should incorporate a two- layered closure, and epicardial exclusion at least two
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(a) (b)
(c) (d)
Fig.67.1 Box lesions in left atrium. (a)Isolation of right pulmonary veins; (b)isolation of left pulmonary veins; (c)connection lesions between inferior
pulmonary veins; (d)connection lesions between superior pulmonary veins.
sutures. It is important to examine the LAA stump suture line while
still on cardiopulmonary bypass because it is most easily repaired
before weaning from bypass.
Aer the ablation procedure, a standard CABG procedure is
carried out.
The choice ofthelesions
e surgical dilemma here is that many surgeons are reluctant to
open the le atrium in AF ablation for patients with isolated standard
CABG procedure. Furthermore, there is considerable controversy
concerning the need for right atrial lesions in AF patients having
concomitant surgery. Many reports document good results with
le atrial lesions alone., However, a subsequent meta- analysis of
5885 patients demonstrated superior long- term freedom from AF in
patients receiving lesions in both atria.
It is important to remember that adding a maze procedure adds
only 9 minutes of cross- clamp and cardiopulmonary bypass time
without increasing morbidity and mortality of patients undergoing a
CABG procedure. Patients undergoing CABG as the primary surgical procedure may present with either concomitant paroxysmal
AF or concomitant persistent and/ or long- standing persistent AF;
the latter two categories likely have a dierent pathogenesis, and,
in those cases, isolation of the pulmonary veins alone may not be
adequate. erefore, we recommend isolation of pulmonary veins
with LAA excision/ exclusion in high- risk patients or patients with
paroxysmal AF; and a complete biatrial maze procedures and LAA
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