Physiological and phenotypic characteristics of late survivors of tetralogy of fallot repair who are free from pulmonary valve replacement

Abstract

Background: Pulmonary valve replacement (PVR) after repair of tetralogy of Fallot is commonly required and is burdensome. Detailed anatomic and physiologic characteristics of survivors free from late PVR and with good exercise capacity are not well described in a literature focusing on the indications for PVR.

Methods and results: Survival and freedom from PVR were tracked in 1085 consecutive patients receiving standard tetralogy of Fallot repair in a single institution from 1964 to 2009. Of 152 total deaths, 100 occurred within the first postoperative year. Surviving patients between 10 and 50 years of age had an annual risk of death of 4 (confidence limit, 2.8-5.4) times that of normal contemporaries. To date, 189 patients have undergone secondary PVR at mean age of 20±13 years (36% of those alive at 40 years of age). A random sample of 50 survivors (age, 4-57 years) free from PVR underwent cardiovascular magnetic resonance, echocardiography, and exercise testing. These patients had mildly dilated right ventricles (right ventricular end-diastolic volume=101±26 mL/m(2)) with good systolic function (right ventricular ejection fraction=59±7%). Most had exercise capacity within normal range (z peak o2=-0.91±1.3; z e/ co2=0.20±1.5). In patients >35 years of age with normal exercise capacity, there was mild residual right ventricular outflow tract obstruction (mean gradient, 24±13 mm Hg), pulmonary annulus diameters <0.5z, and unobstructed branch pulmonary arteries.

Conclusions: An important proportion of patients require PVR late after tetralogy of Fallot repair. Patients surviving to 35 years of age without PVR and with a normal exercise capacity may have had a definitive primary repair; their right ventricular outflow tracts are characterized by mild residual obstruction and pulmonary annulus diameter <0.5z.

Keywords: cardiac surgery; exercise tolerance; magnetic resonance imaging; tetralogy of Fallot.