Assessment of Pulmonary Arterial Hypertension and Vascular Resistance by Measurements of the Pulmonary Arterial Flow Velocity Curve in the Absence of a Measurable Tricuspid Regurgitant Velocity in Childhood Congenital Heart Disease

Abstract

This study aimed to determine mean pulmonary arterial pressure (PAPmean) and pulmonary vascular resistance (PVR) using transthoracic echocardiography (TTE) measurements of the pulmonary artery flow velocity curve in children with pulmonary arterial hypertension (PAH) and congenital heart disease when the tricuspid regurgitant velocity (TRV) is not sufficient. This study enrolled 29 congenital heart disease cases with pulmonary arterial hypertension and 40 healthy subjects followed at our center. The mean age was 66.9 ± 77.9 months in the patient group and 76.3 ± 62.1 months in the control group. A positive correlation was found between TRV and systolic pulmonary arterial pressure (r = 0.394, p = 0.035, 95% confidence interval [CI] = 0.032-0.665), whereas a negative correlation was found between corrected acceleration time (AcTc) and PAPmean (r = -0.559, p = 0.002, 95% CI = -0.768 to -0.242). Furthermore, a negative correlation was found between parameters TRV and AcTc (r = -0.383, p = 0.001, 95% CI = -0.657 to -0.019). Based on the cutoff criterion of 124 ms for AcTc, sensitivity was found to be 79.3% and specificity to be 77.5% in distinguishing between the PAH patients and the healthy control patients (receiver operating characteristic [ROC] area under the curve [AUC] = 0.804, 95% CI = 0.691-0.890, p < 0.0001). The sensitivity and specificity of the concomitant use of AcTc and/or TRV were found to be 90 and 73%, respectively, in distinguishing between the PAH patients and the the healthy control patients. The data obtained by TTE also can be appropriate for measuring PAPmean, PVR, and the vasoreactivity test and for determining the priority of implementing cardiac catheterization even if there is no measurable TRV value.

Normal Reference Values and z Scores of the Pulmonary Artery Acceleration Time in Children and Its Importance for the Assessment of Pulmonary Hypertension

“…Nevertheless, determination of the PAAT could be an important variable during follow-up investigations of pediatric PH patients as it has been shown for adults. 33 For clinical practice, PAAT values from now on can be judged as being normal, or abnormally impaired (shortened), for example, in children with PH. As a noninvasive parameter to detect impaired pulmonary blood flow in children with PH, we suggest including PAAT determination in echocardiographic protocols when evaluating children with a suspected PH.…”

4D magnetic resonance flow imaging for estimating pulmonary vascular resistance in pulmonary hypertension

“…Measurable tricuspid regurgitation Doppler envelopes may not be present in normotensive patients, PH patients with modestly elevated pressures, or in patients with poor acoustic windows due to body habitus. In 2013, Cevik et al (27) attempted to estimate PVR with tricuspid regurgitant velocities in children. This attempt revealed poor results (R 2 = 0.28), but did show that flow patterns were sensitive enough to identify acute vascular reactivity, which offers invaluable proof-of-concept for future studies.…”

Transthoracic echocardiography for the evaluation of children and adolescents with suspected or confirmed pulmonary hypertension. Expert consensus statement on the diagnosis and treatment of paediatric pulmonary hypertension. The European Paediatric Pulmonary Vascular Disease Network, endorsed by ISHLT and DGPK

“…In adults, a PAAT <100 ms is considered abnormal and an indicator for elevated mPAP and PVR 42. In children, a PAAT >124 ms was suggested as cut-off value to distinguish between patients with PH and healthy controls 43. Proper placement of the Doppler sample in the middle of PA and accurate alignment to the long axis of PA is essential.…”