Assessing Myocardial Function in Infants with Pulmonary Hypertension: The Role of Tissue Doppler Imaging and Tricuspid Annular Plane Systolic Excursion.

Transthoracic echocardiography is the most common noninvasive method of evaluating pulmonary hypertension (PH) in infants. Identification of reliable, quantitative indices of myocardial function may enhance the diagnostic value of echocardiography in this population. We hypothesized that pulsed wave tissue Doppler imaging (TDI) and tricuspid annular plane systolic excursion (TAPSE) would be reproducible measurements and would suggest decreased ventricular function, in infants with PH. This retrospective case-control study involved subjects diagnosed clinically and echocardiographically with PH at <12 months of age, matched with controls by age and gestational age (GA). TAPSE was measured by M-mode in the apical 4-chamber view. TDI velocities were averaged from three consecutive cardiac cycles. Observers were blinded to patient identity and clinical status. Fifty-seven subjects, including 35 term or near-term infants ≥35 weeks GA [mean GA 39 weeks (±1.7), median age 1 day (range 0-2)] and 22 preterm infants [median GA 25.4 weeks (24.1-26.6), age 66 days (4-128)], were matched with 57 controls. Subjects with PH had lower TAPSE (term p < 0.001, preterm p = 0.03) and TAPSE indexed to body surface area (term p < 0.001, preterm p = 0.005). Mitral annular, septal, and tricuspid annular systolic (S') and early diastolic (E') TDI velocities were also decreased compared to controls (all p < 0.05). Intraclass correlation demonstrated 84-99% agreement between observers in measuring TDI and 92% for TAPSE. Intraobserver reliability for these measures was 98-99% and 96%, respectively. We concluded that TDI and TAPSE are reproducible indices of myocardial function and may serve as useful adjuncts to standard echocardiographic measures in infants with PH.