Pitfalls in interpretation of the pulmonary valve echogram in patients with congenital heart disease
Echocardiographic assessment of the pulmonary valve is important in patients with congenital heart disease as well as in patients with elevated pulmonary artery pressures. With the use of the pulmonary valve echogram, criteria have been defined for pulmonary hypertension1–3 and correlates have been derived estimating pulmonary artery pressure and pulmonary resistance in these patients.4–7 Pulmonary valve motion has also been described in various congenital cardiac defects including pulmonary stenosis8–10 and transposition.10–16
We describe some potential sources of error in interpretation of the pulmonary valve echogram in a patient with congenital cardiac defects and we question the current criteria and correlations in patients with pulmonary hypertension.
Normal pulmonary valve
The technique for detecting the pulmonary valve echocardiographically has been defined.1, 3, 10, 15 The aortic root is identified by directing the transducer medially and superiorly from the mitral valve. From this position, the ultrasonic beam is then angled superiorly and laterally toward the left shoulder. As the signals from aortic walls disappear, an anterior sonolucent space, which represents the right ventricular outflow-pulmonary root junction, becomes visible. Within this space, the pulmonary cusp echoes appear as thin moving lines. Posteriorly, the pulmonary artery is separated from the left atrium by a thick echo complex produced by structures in the atrial pulmonic sulcus.1, 15 In some patients it is helpful first to locate this thick echo complex, and then by minimal angulation to delineate the pulmonary cusp echoes. In most instances, only the posterior pulmonary cusp can be visualized (Fig. 1).