Background: The impact of gender and age on cardiac function by cardiac magnetic resonance (CMR) in repaired tetralogy of Fallot (TOF) is unknown, which limits the value of currently discussed volumetric thresholds and the accuracy of individual follow-up.
Methods and results: In a nationwide, prospective, 14-center study, 407 consecutive patients with repaired TOF (age, 17.9±8.3 years; range, 8-59 years; 226 male patients) underwent standardized CMR ventricular volumetry and flow quantification (pulmonary artery/ascending aorta). There were no sex differences for age at TOF repair, type of repair, number of prior repair palliations or reinterventions after repair, pulmonary regurgitation fraction, and maximal gradient across the right ventricular outflow tract. Biventricular volumes and mass (indexed to body surface area), available in 380 of 407 patients, respectively, were higher in male patients (P<0.003), but biventricular ejection fraction was higher in female patients (P<0.012). As opposed to reported data of healthy populations, sex-specific reference percentiles computed for an age range of 8 to 40 years (lambda-mu-sigma method) demonstrated (1) an increase of end-diastolic and end-systolic left ventricular volumes, particularly in female patients; (2) an increase of end-systolic right ventricular volumes in both sexes; and (3) a decrease of biventricular ejection fraction in male patients, whereas in female patients, only right ventricular ejection fraction decreased.
Conclusions: Significant gender differences of biventricular volumes, function, and mass by CMR exist late after repair of TOF, suggesting that age and gender cannot be ignored when discussing thresholds. Gender-specific percentiles may present a more relevant framework of reference for an individual patient at a given age and suggest a gradual decline of biventricular systolic function over time.
Trial registration: ClinicalTrials.gov NCT00266188.