CA3 Cardiac Anesthesia Conference: Combined Atrial Fibrillation Ablation Procedures

Atrial Fibrillation Ablation: Convergent Procedure CA3 Cardiac ConferenceAndrew Grandin, MDSeptember 18th, 2013Basics of AFEpidemiology, classification, morbidity, medical management strategiesPrinciples of cardiac electrical propagation and derangements in AFEvolution of AF ablative therapies What are they doing in there?Surgical ablation (Cox Maze III)MIS surgical ablation (Mini-Maze)Catheter ablationConvergent hybrid procedureRationale and patient selection, surgical approach and technical details, efficacy and complications, anesthetic considerations

1Atrial Fibrillation: The BasicsEpidemiologyThe most common sustained cardiac arrhythmiaMore prevalent in men than womenMore prevalent with increasing ageMore prevalent with concomitant heart diseaseThe most common cardiac arrhythmiaAlmost 3 million Americans (That number expected to double in next 25 years)More prevalent in men than womenCardiovascular Health Study (5,201 men and women >65 years): 6.2% of men, 4.8% of women found to have AF on baseline examinationThough women have a higher risk of death from AF complicationsMore prevalent with increasing ageFramingham Heart Study: Men and women at 40 years of age have a 26% and 23% likelihood of developing AF by 80 years of ageMore prevalent with concomitant heart diseaseHypertension, coronary artery disease, valvular disease, rheumatic heart disease

2Atrial Fibrillation: The BasicsMorbidityAF can have adverse consequences related to:Reduction in cardiac outputAtrial and atrial appendage thrombus formationExacerbation of ischemic heart diseaseSymptoms from AF can be debilitatingAF tends to be progressiveAF is an independent predictor of longterm mortality

AF can have adverse consequences related to:Reduction in cardiac outputCan cause/exacerbate CHFAtrial and atrial appendage thrombus formationWith embolic phenomenaExacerbation of ischemic heart disease due to elevated ventricular rate and increased myocardial oxygen demandAF is an independent predictor of longterm mortalitySymptoms from AF can be debilitatingDyspnea, fatigue, anginaAF tends to be progressivePAF to persistent to longstanding persistent

3Atrial Fibrillation: The BasicsCostAn AF patient costs $8,600 more in annual medical costs than a population matched non AF patient$26 billion annuallyOf that $6 billion direct costs of managing AFThis data based on medicare records from 2003-2004.Annual US Healthcare spending: $2.7 trillionAnnual direct medical cost of diabetes: $176 billion4Atrial Fibrillation: The BasicsClassificationParoxysmal AFRecurrent AF (2 episodes) that terminates spontaneously in seven days, usually less than 24 hoursPersistent AFAF that fails to self-terminate in seven days. Often require pharmacologic or electrical cardioversion to restore sinus rhythmLong-standing persistent AFPersistent AF that has lasted continuously for one year or morePermanent AFPersistent AF where the decision has been made to no longer pursue rhythm controlLone AFAny of the above classifications of AF in the absence of structural heart disease. First detected or diagnosed AFIndependent of duration or presence/absence of symptoms

Acute, chronic, intermittent AF have all been terms used in past, but not anymore.Interestingly lone AF tends to be in younger, healthier patients and is more likely to cluster in families than AF with concomitant HD.-- ? Genetic factors5Atrial Fibrillation: The BasicsMedical Management (In 1 slide or less!)Rate versus rhythm control strategiesRate control goalsStrict versus moderateAnticoagulationWarfarin INR 2-3AspirinDabigitranCHADS CHADS2 CHA2DS2-VAScRisk factors predictive of embolic stroke risk

AFFIRM trial and RACE trial. Rhythm control with AAD (antiarrhythmic drugs) does not improve outcome in terms of quality of life, symptoms, or stroke risk. Thus rate control has been pursued except for those with debilitating symptoms from AF or recurrent CVA.Strict rate control (60-80) vs moderate rate control (80-110)Moderate control groups do better

6Principles of cardiac electrical propagation:Whats gone wrong in AF? Multiple re-entrant circuitsParoxysmal AF EP mapping and pulmonary veinsPV lined by endotheliumAtrium lined by endocardiumTransition zone gradual and notable for high electrical activityAutonomous and can fire 300-400 cycles/minPersistent AF features changes in atrial substrate

Pulmonary veins as a predominant trigger in paroxysmal AF was not discovered until 1998 by a French group

Being in AF makes you more likely to stay in AF. (AF begets more AF due to changes in atrial substrate)

7Breaking the circuit:Cox maze III (The Gold Standard)James L Cox MDWork began in 1980Scar tissue in the heart does not conduct electrical impulsesSeveral unsuccessful operations in the mid 1980s1st Maze procedure performed September 25th, 1987Open heart surgery, full CPB, multiple atriotomies on both RA and LA

Per Dr. Buchanan, Dr. Coxs mother had AF and suffered a fatal stroke which inspired Dr. Coxs interest in treating this condition.Several years of lab research and animal models (dogs)The initial objective was to be able to map atrial fibrillation and use the maps to guide what they did, just as had been done with surgeries for WPW and AVRT. So they attempted mapping on patients with AF who were presenting for surgery for other indications (WPW)They realized shortly that mapping was not going to be possible, because of the fleeting nature of the AF re-entrant circuits. They decided to just develop an operation that would preclude the ability of the reentry to occur; if the reentry could not occur in the atrium, then by definition, the atrium could not fibrillate. After having ablated the arrhythmia, they needed to leave the atrium capable of beating in a sinus rhythm,8Breaking the circuit:Cox maze III (The Gold Standard)

Cox et al, 1996

- The combination of those two requirements (obstructing re-entrant circuits while maintaining propagation of sinus impulses) ended up with them placing a maze pattern on the atrium, and it worked very well.- Maze pattern allows one single conduction pathway from SA node to AV node, but also has multiple blind passages that allow for impulse conduction to all areas of atrium and full atrial contraction9Breaking the circuit:Cox maze III (The Gold Standard)198 patients underwent Cox maze III112 with lone AF (64% paroxysmal, 36% persistent)86 with a concomitant cardiac procedure (48% paroxysmal, 52% persistent)

High efficacyIn lone AF group, 92% AF free at 10 yearsIn concomitant group, 97% AF free at 14 yearsNo difference in efficacy between paroxysmal and persistent AF

Why wasnt it widely adopted?

Prasad et al, 2003Morbidity/mortalityARF, IABP, perioperative CVA Perioperative mortality 1.5%Complex lesion patternRisk of LA dysfunction ? need for PPM (about 8% of patients who had a normally functioning SA node preop)

One note on the efficacy figure, f/u less rigorous than with current AF studies- Diagnosis of AF recurrence was largely dependent on patient self report.10Breaking the circuit:Cox Maze III Mini maze Wolf Mini maze (MIS)Simplified lesion setsPVI, LOM, ganglionated plexi LA, LAAEnergy ablation versus physical cut and sewThoracoscopy versus sternotomyOff pump versus on pumpExcellent results for paroxysmal AF

Pulmonary vein isolation, ligament of Marshall and ganglionated plexi ablation, left atrial appendage exclusion.Multiple energy sources have been utilized: electrocautery, cryoablation, microwave, radiofrequency ablation.All work, just need to create transmural , contiguous lesion without gaps.- Shown is one ablation probe (Atricure). Bipolar probe (so energy remains directed between two poles of probe.) Probe senses changes in conductive properties of tissue once a transmural lesion is created.

Less efficacy for persistent and longstanding persistent AF than Cox maze III11Breaking the circuit:Catheter ablationVenous accessFemoralJugularCross interatrial septumEP mappingFluoroscopic and ultrasound guidanceMultiple catheter ablation points to create linear ablations

Breaking the circuit:Catheter ablationlongterm durabilityCohort of 100 patients undergoing their first ablation64% paroxysmal AF, 22% persistent, 14% longstanding persistentArrhythmia-free survival after a single procedure40% at 1 year, 36% at 2 years, 28% at 5 yearsA significant portion required 2 or more ablations to return to NSRArrhythmia-free survival after a last procedure87% at 1 year, 81% at 2 years, 63% at 5 yearsWeerasooriya et al, 2011-- Longer term results (510 years) are now emerging, and it is clear that there is a steady attritionof patients remaining completely arrhythmia-free.-- PV isolation and cavotricuspid isthmus was ablated in every patient. Left atrial linear ablation of the roof and mitral isthmus was generally reserved for patients with persistent or longstanding persistent AF.-- Early recurrence thought due to PV reconnection, later recurrence more likely from non-PV triggering foci as well as atrial substrate changes-- Studies comparing AAD (antiarrhythmic drugs) versus ablation, ablation consistently superior13Weaknesses of single modality ablationsMini mazeInvasiveSternotomy vs thoracoscopyCertain lesions cannot be created by epicardial ablationEP mapping not as sophisticated with epicardial vs endocardial technique

Catheter ablationTime-consumingSome difficulty creating complete linear lesionsSome difficulty creating transmural lesions without injury to other mediastinal structuresRadiation exposureSignificantly less efficacy with persistent AFAbility to ligate LAA?

There are a number of endocardial devices for left atrial appendage exclusion that are currently being tested in trials14

Two specialties have separate procedures for the same condition, each with strengths and weaknesses let the fighting begin!15

Dr Robo VS Dr Corsello Dr Quinn VS Dr Carpenter Dr Weldner VS Dr SesselbergDr Buchanan VS Dr CutlerPlace your bets!16

ElectrophysiologyCardiothoracic SurgeryPutting egos asideCombined proceduresHybrid procedureMIS maze (thoracoscopic) plus EP catheter ablationDual Epicardial Endocardial Persistent AF (DEEP AF) clinical study

Convergent procedurePericardioscopic ablation plus EP catheter ablation

Pericardioscopic ablation

Civello, 2012.

Kiser et al, 2011.Im not sure if this illustration accurately represents the proposed patient population what with the six-pack abs and 10% body fat, but anyway

2.5cm midline incision subxyphoid. Enter the peritoneal cavity. Incise the central ligament of the diaphragm to enter the mediastinum, incise the pericardial sack to access the epicardial surface.19New approach, new toys

To create transmural lesions, need to assure continuous contact with the tissue (not always easy on the beating heart)Suction-assisted devicesUnipolar RFA probeEach linear lesion takes about 90 seconds to createProbe is insulated and saline-cooled to prevent collateral tissue damage20Potential advantagesNo thoracoscopy/thoracotomyNo lung isolationNo need to takedown pericardial reflectionsNo sternotomy/CPBEpicardial unipolar ablation for posterior LA wallEnergy directed away from surrounding mediastinal structuresSingle small incisionPotential issues related to surgical approachLimited visualizationRare potential for great vessel injury without ability for immediate surgical controlCRASH onto bypassExclusion of left atrial appendage not straightforward? Lariat deviceVisualization is guiding epicardial ablation probe placement (not fluoro or ultrasound like with endocardial ablation)

Per Dr Robo, of about 2000 convergent procedure cases in literature, only 5 or 6 cases where CPB was requiredLAA exclusion not as easy as with sternotomy or thoracoscopy- Lariat device is an endoscopic device used for snaring polyps (would be off label use here)22Convergent ProcedureSurgeons goalsElectrically isolate the posterior left atriumAblate the pulmonary veinsAblate the ligament of MarshallRecognize and limit the potential for thermal injury to adjacent mediastinal structures

Electrophysiologists goalsInterrogate pulmonary veins and complete ablationInterrogate posterior left atrium and confirm electrical silence(Ablate the coronary sinus)(Ablate the cavotricuspid isthmus)

Kiser et al, 2011.

Civello, 2012.

Robinson et al, 2012.Convergent procedure: best of both worlds?

*EARLY* resultsSmall, single-center case seriesPatients with persistent or longstanding persistent AFFailed AAD, some failed endocardial ablations or considered unsuitable for catheter ablationRigorous follow-upPromising early resultsFree from AF at 12 months, ~90%Free from AF and off AAD, ~70%Follow-up-3-month blanking period (AAD and anticoagulation continued through this period.) f/u at 3, 6, 9 and 12 months. 24-hour holter monitoring at each interval and 12-lead ECG.27ComplicationsMajorAtrioesophagel fistula (frequently fatal)Symptomatic pericardial effusion/tamponade

MinorPericarditisVentral incisional herniaMost papers atributted AE fistula to the epicardial ablation portion- ? Lost contact from LA or not fully on LA due to poor visualizationEsophageal temp monitoring (stop if 0.4 degree C change)Probe design, vacuum assist to maintain contact, saline cooled to prevent collateral tissue damageSome centers have been performing routine postoperative EGD to pick-up on potential esophageal damage before fistualization occurs

EffusionAll centers leave a pericardial blake drain for 3 days post-op.Still some incidence of late effusions 7-10 days out with tamponade requiring pericardiocentesis28Issues going forward with convergent procedureCost-effectiveness?Expensive ablation probesLong procedure timesAverage 3-day hospitalization post-opEvidence-based benefits?Hybrid approach in feasibility trials (phase I and II)Convergent approach IDE trials still needed for device FDA approvalStandardized ablation lesion patterns?Study endpointsLongterm durability?Current data are small case series with 12 month f/uUnknown if similar attrition rate as seen with catheter ablations aloneWill these approaches show significant, evidence-based improvement in endpoints for this population with persistent and longstanding persistent AF?Not just rhythm control, but decreased stroke risk, improved cardiac output, decreased symptoms/hospitalizations and mortalityWill this procedure allow a significant portion of patients to be free of AAD and anticoagulants and their potential adverse side-effects?29Convergent procedure at MMCAdministrative approval?Roll-outSite visitsLogisticsOR vs EP lab vs both (until hybrid OR, 2015 at the earliest)Likely looking at epicardial portion in OR (with CPB stand-by) and then transport under same anesthetic to EP labDrs. Corsello and Robo are the driving forces from EP and CTS.- Robo has done over 30 of these pericardioscopic epicardial ablations- Corsello has performed over 700 AF ablation proceduresOR 17 not well-equipped for EP procedures. Per Dr Corsello, would run about half a million dollars to change that.30Anesthesia considerationsDevelopment of standardized protocolGETA, single lumen ETTAccessLarge peripheral IVRadial a-line? Central lineIntraoperative anticoagulationTransport from OR to R8Staffing issuesSurgeon would theoretically want less anticoagulation, EP requires full anticoagulation for catheter ablation.- However in talking to Dr Robo, he would allow full anticoagulation during his portion (would not reverse INR)31Questions?

ReferencesOverview of atrial fibrillation. www.uptodate.comwww.stopafib.orgSpector, P. Principles of Cardiac Electric Propagation and Their Implications for Re-entrant Arrhythmias Circ Arrhythm Electrophysiol. 2013;6:655-661Lee et al. Catheter ablation of atrial arrhythmias: state of the art Lancet. 2012; 380: 150919Prasad, et al. The Cox maze III procedure for atrial fibrillation: Long-term efficacy in patients undergoing lone versus concomitant procedures. J Thorac Cardiovasc Surg. 2003;126:1822-8Cox, JL et al. An 8 1/2-year clinical experience with surgery for atrial fibrillation. Ann Surg. 1996; 224(3): 267275Weerasooriya et al. Catheter Ablation for Atrial Fibrillation Are Results Maintained at 5 Years of Follow-Up? JACC. 2011; 57(2):1606Kiser et al. The Convergent Procedure is a Collaborative Atrial Fibrillation Treatment The Journal of Innovations in Cardiac Rhythm Managemen., 2011; 2: 289293Civello, K. Shifting Paradigms: A New Comprehensive Multi-Disciplinary Approach to Atrial Fibrillation EP Lab Digest. 2012; 12(11): 30-1Robinson et al. Maximizing Ablation, Limiting Invasiveness, and Being Realistic About Atrial Fibrillation: The Convergent Hybrid Ablation Procedure for Advanced AF EP Lab Digest. 2013; 13(6): 34-6