Pulmonary Doppler Notch Pattern in Relation with Pulmonary Vascular Resistance Index in Patients with Atrial Septal Defect

Background: Atrial septal defect (ASD) potentially causes pulmonary hypertension (PH) and increased pulmonary vascular resistance (PVR). In previous studies, pulmonary Doppler notch was evident in patients with high PVR. There was a distinct notch pattern in different types of PH. This study aims to examine whether echocardiographic notch pattern could estimate PVR in secundum ASD patients. Methods: Cross sectional study was conducted in secundum ASD patients ?18 years old who underwent clinically indicated right heart catheterization. Association of notch presence and PVR index (PVRi) and correlation of notch ratio (NR), a parameter of notch location, and PVRi were analyzed. The best cut off of NR value was obtained using the receiver operating characteristics curve. Results: Among 60 patients, the notch was present in 50 patients (83%) and significantly associated with PVRi ?6 WU.m2 (p<0.0001). Notch ratio and PVRi had a moderate negative correlation (r=-0.410, p=0.003). Receiver operating characteristics curve with area under curve 0.709 showed that cutoff NR value of 1.635 was a good discriminator for PVRi ?6 WU.m2, with 70% sensitivity, 70% specificity, 56.8% positive predictive value, and 14.9% negative predictive value. Patients were then classified into three groups of notch pattern based on its presence and location, which was significantly associated with PVRi (p<0.0001). Conclusions: Pulmonary Doppler notch pattern is associated with PVRi in secundum ASD patients. This may be used clinically to estimate PVR to aid patient selection for further invasive investigation.   Keywords: atrial septal defect, Doppler echocardiography, notch, notch ratio, pulmonary vascular resistance