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Contemporary Surgical Therapy for Atrial Fibrillation

Contemporary Surgical Therapy for Atrial Fibrillation. John F. Grehan , M.D., Ph.D. AllinaHealth United Heart and Vascular Clinic Minneapolis Heart Institute Grand Rounds April 1 , 2013. Objectives.

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Contemporary Surgical Therapy for Atrial Fibrillation

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  1. Contemporary Surgical Therapy for Atrial Fibrillation John F. Grehan, M.D., Ph.D. AllinaHealth United Heart and Vascular Clinic Minneapolis Heart Institute Grand Rounds April 1, 2013

  2. Objectives • Provide a understanding of AF pathophysiology and clinical impact on the surgical population • Understand the rationale for the Maze IV lesion set • Review preoperative considerations and proper classification of AF patients • Understand how to safely and efficiently complete each step of the concomitant Maze IV procedure • Discuss postoperative and post discharge considerations

  3. Overview • Pathophysiology of AtrialFibrillaiton • Rationale for Concomitant Treatment • Challenges to the Adoption of Treatment • Rationale for the Cox Maze IV lesion set • ABLATE Study • Patient Selection Criteria • Post ABLATE Trial • Summary • Conclusions

  4. AF Pathophysiology & Patient Impacts Rev A

  5. Pathogenesis of AF • Multiple-wavelet hypothesis1 • Focal mechanism with fibrillatory conduction2 • “Autonomic” hypothesis3 Taken from 2007 HRS Guidelines • Moe GK, Abildskov JA. Am Heart J. 1959;58(1):59-70. • Konings KT, et al. Circulation. 1994;89(4):1665-1680. • Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Circulation. 1996;93(5):1043-1065.

  6. RA LA 17 31 SVC FO 6 IVC CS Focal Origin of AF • 94% of atrial triggers in PVs (45 pts) • The pulmonary veins are an important source of ectopic beats, initiating frequent paroxysms of AF • These foci respond to treatment with RF ablation Pulmonary Veins 11 Hassaiguerre M, NEJM, 1998.

  7. Pulmonary Veins • Myocardium extends 1–4cm into vein • Complex fiber orientation • Site of embryological pacemaker tissue • Exhibits automaticity and triggered activity • Lower refractory periods Myocardium extends from the atrium along the pulmonary vein

  8. Macro-Reentrant Circuits Substrate modification occurs due to near continuous firing in the cells and some cells with the atria begin to fire without being (externally) activated creating additional triggers

  9. The Rationale for the Maze IV Lesion Set

  10. Risks of Untreated AF – Target Population • Structural heart disease requiring: • Mitral valve surgery • Aortic valve surgery • Coronary artery bypass • Mayo Clinic/Cleveland Clinic Investigations: • Compared subjects with Preoperative AF vs. no AF • No AF Ablation surgery performed • Statistical matching

  11. Risks of Untreated AF in Cardiac Surgery Patients

  12. Midterm survival in patients treated for atrial fibrillation: A propensity-matched comparison to patients without a history of atrial fibrillation 3262 consecutive patients 813 with AF and 2449 w/out AF undergoing cardiac surgery April 2004 to April 2009. The American Association for Thoracic Surgery doi:10.1016/j.jtcvs.2012.02.006

  13. Improved Patient Survival With Concomitant MAZE Procedure Compared With Heart Surgery Alone Conclusions. The restoration of sinus rhythm by a Maze procedure combined with heart surgery markedly improved long-term survival in this series. Ann ThoracSurg 2009;87:440-7

  14. Conclusions. AF associated with mitral valve disease should be treated, because restoration of the sinus rhythm might lead to a lower incidence of thrombo-embolism and valve-related complications in the later period.

  15. Challenges to Adoption Concomitant AF Treatment

  16. 25 Years of Surgical AF Treatment Dr. Cox reports high success rates with “Cut and Sew” Maze procedure. Period of significant trial and error in energy sources and lesion sets to increase adoption and reproducibility. Opportunity to standardize procedure through rigorous training.

  17. Do Societies Recognize Surgical AF Treatment Or Is This Still Considered “Investigational?” “It is advisable that all patients with documented AF referred for other cardiac surgeries undergo a left or biatrial procedure for AF at an experienced center, unless it… will add significant risk… Heart Rhythm Society, European Heart Rhythm Association, and European Cardiac Arrhythmia Society, in collaboration with the American College of Cardiology, American Heart Association, and Society of Thoracic Surgeons. Consensus Statement on CA and Surgical AF 2012

  18. The ISMICS Consensus Recommendations Concomitant surgical ablation is recommended to increase the incidence of sinus rhythm both at short- and long-term follow-up (class 1, level A) to improve ejection fraction and exercise tolerance (class 2a, level A) and to reduce the risk of stroke and thromboembolic events, to improve long-term survival (class 2a, level A).

  19. Under-Treatment by Procedure • (ICD-9 427.31) Source: Agency for Health Care Quality and Research (AHRQ) Cost and Utilization Project Nationwide Inpatient Sample 2009

  20. Structural Heart Disease Procedureswith Pre-Existing AF Diagnosis US Concomitant AF Treatment Rates – STS Database 67% 76% 62% 48% Source: Gammie, Annals 2008;85:909-15

  21. Surgeon Survey, “Why Don’t You Routinely Perform Maze Procedure on Surgical Patients with Pre-Op AF?

  22. Do we increase the operative risk by adding the Cox Maze III procedure to aortic valve replacement and coronary artery bypass surgery? Ad et al. J Thorac CardiovascSurgJan 2012

  23. Keys to Maze IV Adoption • Standardization on concomitant procedure • Focus on safety and efficacy • Provide reference materials and support throughout the learning curve • Build a substantial body of evidence on durability of outcomes

  24. Rationale for the Maze IV Lesion Set

  25. Surgical Treatment of Atrial Fibrillation:The Cox Maze Procedure • Are all the left atrial lesions necessary? • There have been virtually no randomized trials, but there are observational data.

  26. Surgical Treatment of Atrial Fibrillation : How about pulmonary vein isolation alone ?

  27. PULMONARY VEIN ISOLATION ALONE IS NOT EFFECTIVE IN PATIENTS WITH PERMANENT AF AND VALVULAR HEART DISEASE • 105 patients with AF undergoing valve surgery were randomly assigned to three groups: “U” or “7” linear cryoablation of left atrium or PV isolation • Mean ablation time: 18 ± 3, 15 ± 4, 14 ± 4 minutes for U, 7, and PVI respectively. Gaita et al. Circulation 2005;111:136-142

  28. Mean follow-up: 41 ± 17 months • Successful lesion creation by EAM: 0% (0/17) U lesions 65% (11/17) 7 lesions 71% (12/17) PVI • NSR at last follow-up: 76% (13/17) U lesions 76% (13/17) 7 lesions 29% (5/17) PVI Gaita et al. Circulation 2005;111:136-142

  29. PULMONARY VEIN CRYOABLATION FOR CHRONIC AF • 101 pts having concomitant cardiac surgery underwent PVI with spherical cryoprobe • Mean age: 63 ± 12 years • Mean AF duration 3.4 ± 3.3 years • NSR at discharge: 75% • NSR at last follow up: 53% • NSR without AA drugs at last followup: 25% Isobe et al.CircJ 2005;69:446-455

  30. Left Atrial Lesions of the Cox-Maze IV Superior connecting lesion Inferior connecting lesion

  31. Right atrial lesion set of the Cox Maze IV

  32. 94% had 24 hr Holter (3,6,12 months) Compliant to HRS Guidelines for definition of success (no AF, AT, Flutter off of AADs) CM-IV: Predictors of Late Recurrence Multivariate Analysis (n=282) Damiano et al. J ThoracCardiovascSurg 2011

  33. The Cox Maze IV for Lone AF: A single center experience in 100 consecutive patients Freedom from ATAs at 12 Months Isthmus lesion Weimar T et al J Interv Card Electrophysiol; 2011

  34. Are the Right Atrial Lesions of the Cox-Maze IV Necessary?

  35. Left Atrial Ablation Versus Biatrial Ablation in the Surgical Treatment of Atrial Fibrillation Breda et al Comparison of Bilateral and Unilateral RF Ablation In RF: Early Results

  36. Bi-Atrial VS. Left Atrial Barnett SD, Ad N. J Thorac Cardiovasc Surg: 2006;131:1029-30

  37. Surgical Treatment of Atrial Fibrillation in Mitral Valve Disease: Left Atrial Ablation • Meta-analyses have shown significant differences (87 vs 73%, p=.05) between bi-atrial and left lesion set Ad et al. J ThoracCardiovascSurg 2006;131:1029 • Results have been very variable with left atrial ablation (range 21-95%) and are dependant on the technology used, the lesion set, and the patient population. • A well designed randomized trial showed only a 44% success rate at 1 year for LA ablation ! Doukas et al. JAMA 2005;294:2323

  38. What are the important lesions of the Cox Maze procedure? Conclusions • All of the left atrial lesions are needed to ensure a success rate of over 80% and to prevent late left atrial flutter. • The right atrial lesion set adds to the overall success rate but may not be necessary in all patients. However, in patients undergoing valve surgery, it takes only 10-15 minutes to perform and adds little morbidity.

  39. ABLATE Primary Endpoints • Primary Safety Endpoint • Composite of Death, Stroke, TIA, MI and Excessive Bleeding within 30 days or prior to hospital discharge • Primary Efficacy Endpoint • AF Free (24 hr Holter) and off Class I and III antiarrhythmic drugs at 6 months

  40. Left Atrial Lesion Set Checklist KEY: Blue lines represent typical clamp lesions. Orange line represents typical cryo lesions. Purple line represents surgical incisions. Right Pulmonary Veins

  41. Right Atrial Lesion Set Checklist Connecting lesion along medial walls of RAA toward TV annulus Left Pulmonary Veins KEY: Blue lines represent typical clamp lesions. Orange lines represent typical cryo lesions. Purple oval represents RAA otomy.

  42. ABLATE: Enrolled Patient Disposition 55 Patients Enrolled n=2 Patients expired 53 Patients@ 30 day follow up n=2 Patients expired, n=1 withdrawal 50 Patients@ 6 Months n=2 Patients expired 48 Patients Long-term Median= 21.6 Months

  43. ABLATE: Demographics

  44. ABLATE: Demographics

  45. ABLATE: Baseline AF Status Paroxysmal Subjects:* LA Size > 5 cm: (3/4); Hx of AF > 12 mos (4/4)

  46. ABLATE Primary Surgical Procedure

  47. ABLATE Primary Safety Endpoint- Results

  48. Primary Safety Endpoint – Major Adverse Event Rate: Non-paroxysmal Population N= (5/51) N= (5/64)

  49. Six Month Efficacy: Non-paroxysmal Population Success Rate (Primary Endpoint) (Secondary Endpoint) N= (34/46) N= (38/46) N= (9/11) N= (10/11) N= (43/57) N= (48/57) Data on File

  50. Patient Selection & Patient Considerations

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