Maze Surgical Ablation (Open Chest)
Maze surgical ablation, also called Cox-Maze IV, Modified Maze, or Surgical Pulmonary Vein Isolation, evolved from the Cox-Maze III cut-and-sew procedure. Instead of using incisions, Maze surgical ablation applies an energy source to create a conduction block of scar tissue that stops the errant electrical signals. Maze surgical ablation is faster and just as effective. 1
As an open-chest procedure, it is usually performed on patients needing open-heart surgery for another issue, such as a valve replacement or repair or a coronary artery bypass (CABG). That's called a "concomitant surgery", meaning that it's done along with some other procedure. It is performed on either a stopped or a beating heart.
While this open-chest procedure is sometimes done on patients with "lone atrial fibrillation", more often lone afib cases are handled by a closed chest procedure, minimally-invasive (Mini-Maze) surgical ablation.
Maze Surgical Ablation (Open Chest)
Image courtesy of AtriCure, Inc.
A variety of surgical ablation energy sources may be used to create the conduction block. For example, if radiofrequency (RF) energy is used, a clamp delivers the RF energy to the pulmonary vein and the device can confirm when conduction block is achieved.
While the FDA has only approved medication for treating atrial fibrillation, surgical approaches are currently undergoing clinical trials to establish their effectiveness in treating and curing atrial fibrillation. If medicine isn't managing and controlling your afib, you may wish to discuss surgical procedures with your doctor. For more information, see Partnering With Your Doctor.
If you're considering Maze surgical ablation for treating and curing your atrial fibrillation, you need to know about the success rates and the risks.
Maze Surgical Ablation Success Rates
Like the Cox-Maze III procedure, open-chest Maze surgical ablations have high success rates, including those using a variety of energy sources. Recent examples include:
- A 2004 report of patients treated at Washington University (St. Louis) School of Medicine using a bipolar radiofrequency ablation system reported that 91% were afib-free after six months, and that 75% of those did not require antiarrhythmics. 2
- A 2005 worldwide multicenter study reported that 85% of patients having epicardial (outside of the heart) beating-heart surgical ablation using high-intensity focused ultrasound (HIFU) were afib-free after six months, including 80% of patients with permanent atrial fibrillation. 3
- A 2005 report from the Department of Cardiothoracic Surgery at New York Presbyterian Hospital-Weill Cornell Medical Center reported that 88.5% of patients having open chest Maze surgical ablation using argon-based endocardial (inside the heart) cryoablation (cold temperatures) were afib-free after 12 months. 4
- A 2006 report to the American Association for Thoracic Surgery (AATS) annual meeting compared Cox-Maze III surgery to Maze surgical ablation using bipolar radiofrequency ablation and found that surgical ablation decreased the time required and maintained the efficacy such that more than 90% of patients in each group were afib-free after 12 months. 5
Many centers doing this surgery also cite freedom from stroke in excess of 99%.
Maze Surgical Ablation Risks
Complications from Maze surgical ablations are generally less than 1%. In the early days of Maze surgical ablation, some risks were related to the energy source used. With the earliest devices, surgeons estimated ablation times, which varied from patient to patient due to differences in heart wall thickness, which led to some early injuries. 5 For example, perforation of the esophagus occurred in about 1% of patients where unipolar radiofrequency (RF) energy was used. 6 Safer bipolar radiofrequency energy sources now measure conductivity and determine when conduction block (transmurality) is achieved.
Other reported and generally minor complications include fluid retention and cardiac arrhythmias the first few weeks after surgery. Those usually subside as the heart and body heal.
In addition, some patients need a permanent pacemaker due to injury in surgery or because atrial fibrillation hid problems with their natural pacemaker. A review of the research finds that percentage varies by surgeon experience and energy source. In the high-intensity focused ultrasound (HIFU) study reported above 8% of patients needed a pacemaker 3, and in the cryoablation study above 19% of patients did. 4 Finally, for those patients having arrested heart surgery, there may be risks associated with being on the heart-lung machine.
If you want to know more about Maze surgical ablation for treating and curing your atrial fibrillation, see What to Expect from Maze Surgical Ablation for how to know if you're a candidate for Maze surgical ablation and what to expect before, during, and after the procedure.
1 Lall, Shelly C., et al, "The Impact Of Ablation Technology On Surgical Outcomes Following The Cox Maze Procedure: A Propensity Analysis," <http://jtcs.ctsnetjournals.org/cgi/content/abstract/133/2/389>, Journal of Thoracic and Cardiovascular Surgery, 2007;133:389-396.
2 Gaynor, Sydney L., et al, "A prospective, single-center clinical trial of a modified Cox maze procedure with bipolar radiofrequency ablation" <http://jtcs.ctsnetjournals.org/cgi/content/abstract/128/4/535>, Journal of Thoracic and Cardiovascular Surgery, 2004;128:535-42.
3 Ninet, Jean, MD, et al, "Surgical ablation of atrial fibrillation with off-pump, epicardial, high-intensity focused ultrasound: Results of a multicenter trial" <http://jtcs.ctsnetjournals.org/cgi/content/abstract/130/3/803>, Journal of Thoracic and Cardiovascular Surgery, 2005;130:803.
4 Mack, Charles A., MD, et al, "Surgical Treatment of Atrial Fibrillation Using Argon-Based Cryoablation During Concomitant Cardiac Procedures" <http://www.circ.ahajournals.org/cgi/content/abstract/112/9_suppl/I-1>, Circulation, 2005;112:I-1 – I-6.
5 Damiano, Ralph J., Jr., MD, "Alternative energy sources for atrial ablation: judging the new technology"<http://ats.ctsnetjournals.org/cgi/content/full/75/2/329>, The Annals of Thoracic Surgery, 2003;75:329-330.
6 Doll N, Borger, et al, "Esophageal perforation during left atrial radiofrequency ablation: Is the risk too high?" <http://jtcs.ctsnetjournals.org/cgi/content/abstract/125/4/836>, Journal of Thoracic and Cardiovascular Surgery, 2003 04 (Vol. 125, Issue 4).
