Cox-Maze III: The Gold Standard Treatment for Atrial Fibrillation

Developing a Surgical Option for Atrial Fibrillation

In 1987, Dr. James Cox developed a surgical strategy for addressing atrial fibrillation (AF). The surgery, called the Cox-Maze I, was intended to create a "maze" of small incisions along both the right and left atria. The incisions would heal, thus creating scar tissue that would inhibit the reentry of the irregular electrical impulses that cause atrial fibrillation. In 1992, after two subsequent modifications, the Cox-Maze III surgery became the gold standard technique for alleviating atrial fibrillation in an open-heart surgical procedure.64

The Cox-Maze III Procedure

The Cox-Maze III procedure, also known as cut-and-sew  maze, is performed during an open-heart surgery on a non-beating (arrested) heart during cardiopulmonary bypass. A specific "maze" of incisions is made along both the left and right atrium. These incisions either block or reroute the renegade electrical impulses that cause the atria to contract in uncoordinated rhythms. The resultant scar tissue from the incisions directs impulses through the SA node and down into the AV node along proper pathways. Additionally, the left atrial appendage is excised.64

Cox-Maze III Success Rates

The Cox-Maze III procedure can be performed either alone or concomitantly during a mitral valve or other open-heart surgery. Studies have shown little or no difference between the success rates of open-heart lone or concomitant procedures.42 The success rates of the Cox-Maze III procedure depends on many factors, including the classification of atrial fibrillation and how long the patient has had atrial fibrillation.

In one study, conducted by the Division of Cardiothoracic Surgery, Washington University School of Medicine in St. Louis showed that 98% of patients had no recurrence of atrial fibrillation at 10 years after surgery.67 One patient had a recurrence of atrial fibrillation after 10.5 years. 84% of patients in the study were in normal sinus rhythm without antiarrhythmic drugs.67 The study states, "…freedom from AF for patients undergoing a Cox-Maze procedure and concomitant surgical intervention for ischemic heart disease was 100% at 10 years."67 None of the patients in the study suffered a stroke during the 10 year follow-up period.67 Overall, studies with different patient populations have reported success rates of 72-98%.43, 67

Cox-Maze III Limitations

The Cox-Maze III is the best possible surgical option for almost all patients with atrial fibrillation who are healthy enough to have an open-heart procedure.65 Unfortunately, because of the complexity of the procedure and the technical difficulty of the incision set, only a few cardiac surgeons can perform the surgery. During concomitant open-heart surgery, the incision set also adds to the length of an already time-consuming surgery, increasing certain risks associated with an open-heart cardiopulmonary bypass procedure. This has resulted in limited use of the procedure in both lone and concomitant open-heart procedures.44 Many of the risks of any open-heart cardiopulmonary bypass surgery exist for the Cox-Maze III procedure. 

In writing about the complexity of the Cox-Maze III procedure, Dr. Cox has stated that, "The maze III procedure is so complex that its adoptability is minimal. This results in an operation that despite being safe (operative mortality = <1%) and effective (cure rate = >98%) has had little direct effect on the absolute number of patients cured of atrial fibrillation."65