Cardiovascular Screening in Infants Born Small for Gestational Age
Condition: Cardiovascular Abnormalities; Small-for-gestational Age
MeSH terms: Cardiovascular Abnormalities
Study type: Observational

Summary: 
      Aims of this study were 1) to evaluate early CV abnormalities in infants born small for
      gestational age (SGA) at 24 months of age compared with age and sex-matched subjects that
      were born adequate for gestational age (AGA) 2) to investigate the effect of catch-up growth
      and the role of breastfeeding on CV risk.
    

Detailed description: 
      We consecutively enrolled 20 SGA infants, born at term (37+0/41+3 week gestation), aged 24
      months, and 20 AGA, age- and sex-matched controls. SGA was defined as a birth weight <10th
      percentile for sex, gestational age and birth order, and AGA as a birth weight between the
      10th and the 90th percentile, according to Italian neonatal anthropometric charts.

      Clinical and anthropometric variables The infants' prenatal and neonatal data were
      retrospectively recorded, namely a history of gestational diabetes and hypertension, the
      presence of intrauterine growth restriction, maternal weight gain during pregnancy, Apgar
      score, gestational age and birth weight, length, and head circumference. All subjects'
      parents completed a questionnaire including family history, maternal smoking during
      pregnancy, breastfeeding duration. At the time of enrollment (24 months), anthropometric data
      were evaluated by trained physicians according to standard procedures and based on the WHO
      growth charts. Height, weight, systolic (SBP) and diastolic (DBP) blood pressure were
      measured. Body mass index (BMI) was calculated as weight (kg)/height(cm)2 and weight gain in
      the first 2 years of life was calculated as the delta between birth weight and weight at 24
      months.

      Echocardiographic assessment Transthoracic echocardiogram using a Vivid 7 Pro ultrasound
      scanner (General Electric Healthcare, USA) was performed by an expert pediatric cardiologist,
      blinded to patients' clinical data. Measurements of left ventricle (LV end-diastolic
      diameter, LVEDD; LV end-systolic diameter, LVESD; interventricular septum at end diastole,
      IVSD; LV posterior wall at end diastole, LVPWD), relative wall thickness (RWT), left atrium
      diameter (LAD), the maximum LA volume, LV ejection fraction, and tricuspid annular plane
      systolic excursion (TAPSE) were obtained according to established standards. LV mass (LVM)
      was derived from the Devereux formula and indexed to body surface area (left ventricular mass
      index, LVMI). Left ventricular output (LVO) was obtained with the velocity time integral
      (VTI) from a 5-chamber view and calculated as follows LVO=[(VTI)x(heart
      rate)x(cross-sectional area)] and indexed to body weight.

      Using pulsed wave Doppler, mitral inflow velocities, peak early diastolic velocity (E), peak
      late diastolic velocity (A), and E/A ratio, were measured. Pulsed wave tissue Doppler of the
      lateral mitral annulus was used for the measurement of early peak diastolic mitral annular
      velocity (E'). The E/E' ratio was calculated. End-diastolic pressure (EDP) was calculated
      from the E/E' ratio with the formula EDP=1.91+1.24xE/E' (14) and the pressure-volume curve
      during diastole with the formula EDP = αxEDVβ (end-diastolic volume, EDV). Volume parameters
      were corrected to fixed values of EDP (V30 mmHg). The coefficient "β" (Beta), indicating the
      slope of the end-diastolic pressure-volume relationship (EDPVR), was calculated with the
      formula β=[Log10(EDP/30)]/[Log10(EDV/V30mmHg)].

      Vascular assessment Vascular measurements were performed with a high-resolution
      ultrasonography (Esaote MyLab25TM Gold, Esaote, Italy) using a 8 mHz linear transducer and a
      5 mHz convex transducer for the abdominal aorta, by an expert vascular surgeon blinded to
      patients' clinical status. CIMT, abdominal aortic diameter at maximum systolic expansion (Ds)
      and minimum diastolic expansion (Dd), brachial artery diameters, brachial artery peak
      systolic velocity (PSV) and end diastolic velocity (EDV) were measured as previously
      described and aortic strain (S), pressure strain elastic modulus (Ep), pressure strain
      normalized by diastolic pressure (Ep*) and brachial artery flow-mediated dilation (FMD) were
      calculated. While S is the mean strain of the aortic wall, Ep and Ep* are the mean stiffness
      (16). Arterial wall stiffness index (β index) was calculated with the formula: β
      index=ln(SBP/DBP)/[(Ds-Dd) /Dd)] (17) and systemic vascular resistance (dynes/s/cm2) with the
      formula: SVR=(mean BP- right atrial pressure)/LVO, with an estimated right atrial pressure of
      5 mmHg. The brachial artery maximum diameter recorded following reactive hyperemia was
      reported as a percentage change of resting diameter (FMD = peak diameter - baseline
      diameter/baseline diameter).
    

Observational model: Case-Control
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        We consecutively enrolled 20 SGA infants, born at term (37+0-41+3 weeks gestation), aged 24
        months, and 20 AGA, age- and sex-matched controls. SGA was defined as a birth weight <10th
        percentile for sex, gestational age and birth order, and AGA as a birth weight between the
        10th and the 90th percentile, according to Italian neonatal anthropometric charts