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Fontan procedure low-risk regardless of ventricular anatomy, study suggests

Thursday, October 09 2008 | Comments

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What's This? An analysis of 15-year, single-center experience with the Fontan procedure indicates that it is a low-risk technique irrespective of ventricular anatomy, and that increased cross-clamp (XC) time and prolonged chest tube (CT) drainage are the factors most likely to decrease survival.

Researchers reviewed the University of Michigan Congenital Heart Surgery database for the period between July 1992 and June 2007 and performed a cross-sectional retrospective analysis of the 636 patients with single-ventricle physiology who had a Fontan procedure during that time.

The primary study endpoint was to evaluate the contemporary risk factors for mortality and morbidity. The primary late outcomes were survival, New York Heart Association functional class, and ventricular function. Secondary late outcomes included significant late morbidities, such as arrhythmia, protein-losing enteropathy (PLE), and neurologic events.

Median patient age was 24 months (range, 20-31 months). Left ventricular hypoplasia was present in 64% of the patients (n=405) and right ventricular hypoplasia in 36% (n=231). Hypoplastic left heart syndrome (HLHS) was present in 52% of patients (n=330).

Depending on their individual anatomy, the patients had either a hemi-Fontan procedure or a bidirectional Glenn as their initial palliative procedures. Patients with a prior hemi-Fontan subsequently had a lateral tunnel (LT) Fontan (92%), and those with a previous Glenn procedure had an extracardiac conduit (EC) performed (8%) as the final palliative procedure. Fenestrations were performed in all LT patients as opposed to only 35% of EC patients.

Median length of stay was 10 days, and 96% of patients survived hospitalization. Of these, 94% had an intact Fontan pathway. Fontan takedown was necessary in 3% of patients with a subsequent mortality of 41%. Mean follow-up was 50 months, and late survival was 97% among those who survived hospitalization. Survival was 96% in patients with an intact Fontan pathway. Long-term survival was 95%, 93%, and 91% at 5, 10, and 14 years, respectively.

Although LT patients had better perioperative outcomes, there was no significant difference in long-term survival between LT and EC patients. Increased cardiopulmonary bypass time was shown to significantly decrease short-term survival (P=.0002) but did not affect long-term survival (P=.34). Increased aortic XC time negatively affected both short- and long-term survival (P=.01 for both). Patients with prolonged CT drainage were significantly less likely to survive hospitalization (P=.026) and had significantly worse long-term survival P<=.0001). CT drainage was prolonged (>2 weeks) in 19% of the patients and was more common in EC patients (33%) than in LT patients (18%; P=.007) and in patients with dominant morphologic right ventricles versus dominant morphologic left ventricles (21% vs 15%; P=.035).

Six percent of patients had PLE, which was significantly more likely among patients with prolonged CT drainage (P<=.0001) and among patients with a dominant morphologic right ventricle as opposed to a dominant left ventricle (9% vs 2%; P=.001).

The researchers also analyzed the procedures according to 3 different time periods during which they were performed to evaluate whether there had been a significant change in outcomes during the course of the study. Although hospital survival demonstrated significant improvements (P=.0001), no concomitant increase in long-term survival has been observed. Also, the number of patients with prolonged CT drainage has decreased over time, although this has not caused a decrease in the incidence of PLE.

This study demonstrates that the Fontan procedure affords excellent survival with low perioperative morbidity, the researchers concluded. The increase in long-term survivors has shifted the focus to functional status and late morbidity, they added. (Hirsch JC, et al. Ann Surg 2008; 248:402-410.)

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