Physiological and Phenotypic Characteristics of Late Survivors of Tetralogy of Fallot Repair Who Are Free From Pulmonary Valve Replacement

Study Questions:

What are the anatomic and physiologic characteristics of late survivors of tetralogy of Fallot (TOF) repair who are free from late pulmonary valve replacement (PVR)?

Methods:

A consecutive series of 1,085 patients undergoing repair of TOF at a single center between 1964 and 2009 was used to track survival and freedom from PVR. A random sample of survivors free from PVR underwent cardiovascular magnetic resonance imaging, echocardiography, and exercise testing.

Results:

A total of 152 deaths occurred, including 100 the first postoperative year. PVR had been performed in 189 patients at a mean age of 20 ± 13 years. Of patients alive at 40 years of age, 36% had undergone PVR. Surviving patients between 10 and 50 years of age had an annual risk of death of 4 times that of normal contemporaries (confidence limit, 2.8-5.4 years). Of the 50 patients selected in the random sample, the mean right ventricular volume was mildly increased at 101 ± 26 ml/m2, and right ventricular function was normal (right ventricular ejection fraction 59 ± 7%). The majority of patients had normal exercise capacity (peak VO2 z-score = -0.91 ± 1.3), with mild residual right ventricular outflow tract obstruction (mean gradient, 24 ± 13 mm Hg), normal to small pulmonary annulus diameter (z-score < 0.5), and unobstructed branch pulmonary arteries.

Conclusions:

A significant proportion of patients require late PVR after TOF repair. For a subset of patients who survive to 35 years of age without PVR and a normal exercise capacity, their primary repair may have been definitive. The right ventricular outflow tracts of these patients are characterized by mild residual obstruction and pulmonary annulus diameter z-score < 0.5.

Perspective:

Much of the emphasis in the care of adults with TOF revolves around the care of patients with significant residua, particularly pulmonary regurgitation, and the need for late re-intervention. This study looked at a subset of patients with overall favorable hemodynamics not requiring PVR. This study demonstrates the importance of decisions made at the time of surgery on long-term outcomes and the need for re-intervention. However, often these decisions are in large part driven by the underlying anatomy faced by the surgeon in the operating room. It would be helpful to directly compare the preoperative and surgical characteristics of this cohort with patients requiring late PVR. These results suggest that it may be beneficial for the repair to result in a low normal or normal pulmonary annulus (z-score -1.3 to 0.5) while tolerating mild residual right ventricular outflow tract obstruction. The authors noted that it is difficult to predict the trajectory of pulmonary annulus growth after repair.

Clinical Topics: Congenital Heart Disease and Pediatric Cardiology, Noninvasive Imaging, Congenital Heart Disease, CHD & Pediatrics and Imaging, Echocardiography/Ultrasound, Magnetic Resonance Imaging

Keywords: Survivors, Tetralogy of Fallot, Ventricular Function, Pulmonary Valve, Magnetic Resonance Imaging, Postoperative Period, Echocardiography, Exercise Test


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