Beyond morphometry: the atrial septal defect pressure gradient as a dynamic predictor of mitral valve growth in borderline left hearts

Key messageTraditional morphometric scores often fail to predict the success of biventricular repair of borderline left hearts.Wang et al. demonstrated that a low atrial septal defect (ASD) pressure gradient is a critical functional predictor of mitral valve growth.By integrating ASD hemodynamics with anatomical data, clinicians can better identify candi dates for biventricular repair, proving that the "grey zone" is narrower than previously thought and improving outcomes for vulnerable neonates.The management of infants with coarctation of the aorta (CoA) or an interrupted aortic arch (IAA) alongside borderline leftsided structures remains among the most complex challenges in pediatric cardiac surgery.Neonates born with borderline left heart hypoplasia or hypoplastic left heart complex can be candidates for biventricular repair, whereas those with severe hypoplasia typically require singleventricle palliation. 1) Because failed biven tricular repair often leads to poor clinical outcomes, 2) there is a critical need for more accurate predictive fac tors to guide highstakes decisions.To identify suitable candidates for biventricular repair, several prediction models such as the Rhodes, CHSS (Congenital Heart Sur geons' Society), Discriminant, and 2V scores have been developed 37) ; however, their predictive accuracy remains limited.These models primarily utilize morphometric parameters, including mitral valve (MV) size, left ventri cular (LV) dimensions, aortic valve size, the presence of an apexforming LV, and endocardial fibroelastosis.Because morphometry alone does not enable precise predictions, clinicians frequently supplement these scores with func tional assessments such as LV function, LV enddiastolic pressure, and blood flow direction in the ascending aorta and the patent ductus arteriosus to improve prediction