Efficacy of Catheter Ablation and Surgical CryoMaze Procedure in Patients With Long-Lasting Persistent Atrial Fibrillation and Rheumatic Heart Disease - Catheter Ablation and Surgical CryoMaze Procedure in Patients With Long-Lasting Persistent Atrial Fibrillation and Rheumatic Heart Disease

Description:

Catheter ablation with pulmonary vein isolation (PVI) is commonly performed for patients with atrial fibrillation (AF), especially paroxysmal AF. Its efficacy in patients with permanent AF, such as those with rheumatic heart disease (RHD), is less enduring. Traditionally, patients with permanent AF undergo a surgical Cox Maze procedure at the time of valve surgery. The current trial sought to compare the efficacy of catheter ablation with PVI following valve surgery versus surgical modified Maze (using cryoablation) at the time of valve surgery.

Hypothesis:

Catheter ablation with PVI after valve surgery would be noninferior to surgical Cox Maze using cryoablation, performed at the time of valve surgery.

Study Design

  • Parallel
  • Randomized

Patient Populations:

  • RHD with need for valve surgery
  • Long-standing (>1 year) persistent, symptomatic AF, refractory to at least one AAD
  • Age >18 years
  • Number of enrollees: 99
  • Duration of follow-up: 1 year
  • Mean age: 54.5 years
  • Female: 55%
  • Mean ejection fraction: 63%

Exclusions:

  • Paroxysmal AF
  • Left atrial thrombus on transesophageal echocardiography prior to procedure
  • Previous AF ablation
  • Need for valve commisurotomy alone

Primary Endpoints:

  • Freedom of any recurrence of atrial arrhythmias lasting 30 seconds, 12 months postablation after one procedure

Secondary Endpoints:

  • Periprocedural complications

Drug/Procedures Used:

All operations were performed by means of a median sternotomy using standard cardiopulmonary bypass. The diseased valve was either repaired or replaced, and the left atrial appendage was sewn at its base in both groups of patients. An additional modified Maze III procedure using the Saline-Irrigated Cooled-tip Radiofrequency Ablation (SICTRA) system (Cardioblate, Medtronic Inc.) was performed in patients randomized to the surgical arm at the time of valve surgery. The SICTRA set-up consisted of a radiofrequency generator and a unipolar catheter. In the catheter ablation arm, patients with postoperative atrial arrhythmias underwent an electrophysiological study and subsequent catheter ablation of AF 6 months after the heart surgery. PVI was conducted using standard techniques.

Concomitant Medications:

At baseline: Amiodarone (9%), class IC antiarrhythmic drug (AAD) (7%). Postprocedure: Patients in both arms were anticoagulated with Coumadin (goal international normalized ratio 2.5-3). All patients also received AADs postoperatively, most commonly amiodarone (as an intravenous load, followed by oral maintenance therapy for 3 months postprocedure).

Principal Findings:

A total of 99 patients were randomized, 49 to catheter ablation with PVI (group A) and 50 to surgical cryoablation (group B). Baseline characteristics were fairly similar between the two arms. The mean duration of AF was about 71 months, with an average left atrial diameter of 6.1 cm. The mean ejection fraction was normal (63%). The majority of patients underwent mitral valve replacement (80%), with either a metallic (69%) or bioprosthetic (11%) valve. In addition, 19% of patients underwent replacement of more than one valve.

At the end of 12-month follow-up, after one catheter ablation or surgical cryoablation, the freedom from atrial arrhythmias was higher in group B than in group A (82% vs. 55.2%, p < 0.001). A total of 4 and 8 patients in groups A and B needed repeat ablation with PVI. AF-free survival was higher in group B (88% vs. 71%, p < 0.001). Complication rates were low, and similar between the two arms. Two patients in group A had a significant complication—one stroke and one catheter entrapment in mechanical valve.

Interpretation:

The results of this small trial indicate that surgical Maze at the time of valve surgery (performed using cryoablation) is superior to catheter ablation with PVI after valve surgery, in terms of freedom from AF and need for repeat procedures, in patients with RHD and AF. Since RHD is less frequently encountered in the western world, these findings are valuable. This trial mirrors conventional wisdom on this topic since AF in patients with valvular disease, especially rheumatic, is usually long-standing, and is associated with characteristics such as large atrial diameters and persistent/permanent AF, both of which are known to be associated with inferior outcomes with PVI.

References:

Liu X, Tan HW, Wang XH, et al. Efficacy of catheter ablation and surgical CryoMaze procedure in patients with long-lasting persistent atrial fibrillation and rheumatic heart disease: a randomized trial. Eur Heart J 2010;Jun 23:[Epub ahead of print].

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Valvular Heart Disease, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Cardiac Surgery and Arrhythmias, Cardiac Surgery and VHD, Interventions and Structural Heart Disease

Keywords: Rheumatic Heart Disease, Stroke, Sternotomy, Heart Atria, Pulmonary Veins, Atrial Appendage, Heart Valve Diseases, Cryosurgery, Cardiopulmonary Bypass, Cardiac Surgical Procedures, Catheter Ablation, Mitral Valve


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