Mid-Systolic Notching of the Pulmonary Valve Doppler Signal is Highly Associated with Pulmonary Hypertension

Mid-systolic notching (MSN) of the pulmonary valve Doppler signal represents a reflected systolic pressure wave from the pulmonary vasculature and is often seen in pulmonary hypertension (PH). We hypothesize that MSN is associated with a higher pulmonary vascular resistance (PVR) and mean pulmonary artery pressure (mPAP), and a diagnosis of PH in pediatric patients. This was a retrospective study of patients ≤ 18 years who had an echocardiogram obtained ≤ 30 days before catheterization for suspected PH. MSN was defined as an indentation in the initial two thirds of the systolic Doppler signal. PH was defined as mPAP > 20 mmHg and PVR ≥ 3.0 Wu  m². Subgroups (MSN vs. normal) were compared. Receiver operator characteristic determined a continuous variable's discriminatory ability for a diagnosis of PH. Reproducibility of MSN was assessed. In total, 90 patients (73 with congenital heart disease) were included, of which 36 had MSN and 54 were normal. MSN patients were more likely to have PH, and had significantly higher mPAP, PVR, and lower pulmonary stroke volume. The presence of MSN had good discriminatory ability for PH diagnosis. The presence of MSN had high specificity (96%) for PH, whereas sensitivity was lower (54%). Reproducibility was 100% for MSN. MSN is a simple, highly reproducible echocardiographic metric associated with higher mPAP and PVR. When present, there is a high likelihood a diagnosis of PH confirmed by catheterization. Incorporation of MSN into imaging protocols may be useful. MSN appears worthy of further investigation in pediatric patients with suspected PH.