Hemodynamic Phenotypes in Congenital Diaphragmatic Hernia: Unresolved Questions and Future Directions.

Congenital diaphragmatic hernia (CDH) is increasingly recognized as a dynamic cardiopulmonary disease in which pulmonary hypoplasia, pulmonary hypertension, and cardiac dysfunction interact to shape clinical instability, therapeutic response, and outcomes. Hemodynamic phenotyping has emerged as a strategy to move beyond binary classification of pulmonary hypertension and toward physiology-directed care. Early single-center experiences suggest potential clinical utility of echocardiography-guided, phenotype-directed management; however, external validation remains limited. Further important challenges remain, including technical and institutional barriers to timely echocardiography, limitations of static single-time-point assessments, uncertainty regarding what exactly defines each phenotype, and incomplete understanding of the impact of time and therapies on phenotype presentations. In this perspective, we summarize the evolution of heart-focused care in CDH, describe current hemodynamic phenotyping approaches, examine unresolved questions in phenotype classification and implementation, and outline future research priorities needed to advance dynamic, mechanism-based precision cardiopulmonary care for infants with CDH.