Fontan Conversion Still An Effective Alternative


SAN DIEGO — Fontan conversion accompanied by arrhythmia surgery and pacemaker implantation remains a safe and effective alternative to cardiac transplantation for patients with failing Fontan circulation, Dr. Constantine Mavroudis reported at the annual meeting of the Society of Thoracic Surgeons.

During the past several years patients with failing Fontans have been presenting at an older age, with more complex lesions and more-difficult-to-manage atrial arrhythmias as the increasing popularity of transcatheter ablation procedures has delayed surgical referral.

Yet results remain excellent due to evolution in surgical techniques and advances in pacemaker therapy, said Dr. Mavroudis, the Willis J. Potts Professor of Surgery at Northwestern University and surgeon-in-chief at Children's Memorial Hospital, Chicago.

His retrospective study examined 111 consecutive patients who underwent atriopulmonary to total cavopulmonary artery extracardiac Fontan conversion at the hospital since late 1994.

The patients' mean age was 23 years, with a mean 14-year interval between Fontan and Fontan conversion. Fourteen patients had undergone prior Fontan revisions.

Dr. Mavroudis divided the experience into three periods based upon changes in arrhythmia surgery techniques.

The first epoch consisted of simple isthmus cryoablation, a strategy abandoned after nine patients.

The next 51 had right atrial maze procedures for right atrial reentry tachycardia.

The most recent 51 patients—those treated since 2003—have routinely received the more elaborate biatrial Cox maze-III procedure, which incorporates cryoablation of the left atrium. This change occurred in response to a shift in the predominant presenting arrhythmia from right atrial reentry tachycardia to more challenging cases of atrial fibrillation.

The classic Cox maze-III was supplemented with one additional cryoablation lesion running between the bases of the right and left atrial appendages and across the dome of the atria to reduce the incidence of postoperative atrial tachycardia.

There were one early and six late deaths among the 111 patients. Six patients required cardiac transplantation, with two of the six late deaths in the series coming 4 and 24 days post transplantation. The other four donor heart recipients are alive 5–7 years later.

With follow-up extending to 12 years, 88% of patients have experienced an improvement in New York Heart Association functional class. The arrhythmia recurrence rate was 13.5% overall, declining to just 8% in the most recent group comprised of 51 Cox maze-III-treated patients.

Postoperative arrhythmia recurrence in patients with preoperative refractory atrial fibrillation took the form of atrial tachycardia, Dr. Mavroudis continued, which is far more easily treated.

In a multivariate analysis, the strongest risk factor for death or transplantation was protein-losing enteropathy, present preoperatively in three patients and associated with an 87-fold increased risk.

A right or ambiguous ventricle and preoperative moderate to severe atrioventricular valve dysfunction also predicted poor outcome.

Discussant Dr. Joseph A. Dearani praised Dr. Mavroudis for heading what the congenital heart disease surgery community recognizes to be the world's premier Fontan conversion program.

“The most important contribution from their experience is the thorough understanding of the different atrial arrhythmias that occur in the failing Fontan circulation and their methods of ablation, which have evolved over time,” observed Dr. Dearani, a cardiothoracic surgeon at the Mayo Clinic, Rochester, Minn.

“The importance of the need to address both atria at the time of operation cannot be overemphasized,” he added.

Noting that the late deaths and cardiac transplantations in the Chicago series all occurred relatively early—within a year after Fontan conversion—Dr. Dearani asked whether it might make more sense to consider protein-losing enteropathy, significant atrioventricular valve regurgitation, and severe ventricular dysfunction to be contraindications to Fontan conversion and instead send affected patients directly to heart transplantation.

Dr. Mavroudis, however, answered that he would not yet include atrioventricular valve regurgitation as a contraindication. This is because his recent experience using Alfieri valvuloplasty has, so far, been very encouraging.

At 12 years follow-up, 88% of patients saw an improvement in New York Heart Association functional class. DR. MAVROUDIS

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