Background: Differing diagnostic frequencies and management strategies for intramural hematoma (IMH) have been described in North American (NA)/European and Japanese/Korean studies.
Methods: All publications including type-A aortic IMH were reviewed for details on patient demographics, treatment strategy, and clinical outcomes. Publications were stratified by the geographic region (NA/Europe or Japan/Korea).
Results: IMH, as a percentage of aortic dissection, occurs more frequently in Japan/Korea versus NA/Europe (31.7% vs 10.9%, P < .0001). The proportion of patients treated with early medical therapy is greater in Japanese/Korean studies (77.9% vs 48.8% in NA/Europe, P < .0001). However, the overall mortality is significantly lower in Japan/Korea compared with NA/Europe (9.4% vs 20.6%, odds ratio = 2.80, P = .003) in part because of the lower mortality with early medical therapy (7.8% vs 33.3%, P < .0001).
Conclusion: There is significant international heterogeneity in the diagnosis and clinical outcomes of ascending IMH. IMH is diagnosed more frequently and has better overall outcomes in Japan/Korea.