Natural history of coronary aneurysms associated with Noonan's syndrome.

Coronary artery aneurysms (CAAs) in Noonan syndrome (NS) are rare, and their true prevalence remains unclear. While previous cases have been reported, the natural history of this association and its management have not been described. We present a 31-year-old male followed for over 16 years, who was found to have an uncomplicated thrombus during his most recent coronary computed tomography angiography (CCTA) follow-up. We aim to illustrate the natural history of CAAs in NS by presenting findings from transthoracic echocardiography (TTE) and CCTA, discussing diagnostic challenges, and showing how current Kawasaki disease (KD) guidelines can be extrapolated for management. In conclusion, CCTA and TTE play a pivotal role in monitoring CAA progression and guiding individualized therapeutic strategies, with KD guidelines serving as a reference for management. Learning objective: The association between Noonan syndrome (NS) and giant coronary artery aneurysms (GCAAs) is rare, posing challenges for long-term management. Multimodality imaging, particularly coronary computed tomography angiography, is essential for monitoring GCAA progression, evaluating complications, and guiding thromboprophylaxis and surgery. The potential application of Kawasaki disease guidelines may provide valuable insights into thromboprophylaxis and long-term care in NS patients with GCAAs, helping to address the current lack of condition-specific management strategies.