Collectively, our results indicate that PDGF ligands secreted by other aortic cells, including SMCs, ECs, and macrophages, trigger PDGF signaling pathways by binding platelet‐derived growth factor receptors (PDGFRs) on CD34+ cells to activate CD34+ cells, thereby promoting CD34+ cell migration and transdifferentiation into myofibroblasts during AAA pathology. Here, CD34 is linked to triple-A syndrome.