Response to Letter Regarding Article, “Outcomes of Patients With Acute Type A Aortic Intramural Hematoma”
We appreciate Dr Harris and colleagues’ thoughtful comments on our recent publication.1 They concluded that surgical therapy should still be considered the treatment of choice for most patients with proximal aortic intramural hematoma (IMH) until results from further prospective studies are available. A randomized prospective study is an attractive way to solve the current debate on optimal treatment option. However, depending on the null hypotheses to test, the minimum required number of patients in each group ranges from 100 to >2000. Considering the fact that it took >15 years to enroll 100 patients in our institution with a high prevalence of IMH, it is impractical to start a randomized clinical trial. The regional heterogeneity of diagnostic frequency and outcomes of patients with acute type A IMH are well documented.2,3 It is interesting to see that overall mortality and mortality without emergent surgical intervention are significantly lower in Asian countries. This finding supports our idea that IMH is different from and is not just a precursor of classic aortic dissection, in which emergent surgery is an established treatment option. At this moment, we cannot explain the marked regional difference in patient outcomes. One logical approach to test whether our Asian series included more subtle cases is to reanalyze the Western data to assess IMH severity (aortic diameter and hematoma thickness). Significantly higher mortality with early medical treatment in the Western data might indicate that more patients with poor general condition or comorbidity who could not undergo emergent surgical intervention were included. It should also be tested whether the difference in the total number of patients per institution in the 2 series, potentially reflecting the clinical experience of an individual institution, might affect outcomes.
We do not deny the survival benefit of emergent surgical intervention in patients who are hemodynamically compromised. We just propose a tailored or individualized approach based on risk stratification using initial clinical information, including imaging studies. We know that >50% of patients show regression or resorption of hematoma with medical treatment alone and that timed surgical intervention does not have an additive risk of higher mortality. In a recent publication from the United States, the authors concluded that, in their patient population, timely surgical repair is recommended.4 We hope this can be a positive signal of the paradigm shift in Western countries.
Song JK, Yim JH, Ahn JM, Kim DH, Kang JW, Lee TY, Song JM, Choo SJ, Kang DH, Chung CH, Lee JW, Lim TH. Outcomes of patients with acute type A aortic intramural hematoma. Circulation. 2009; 120: 2046–2052.
Kitai T, Kaji S, Yamamuro A, Tani T, Tamita K, Kinoshita M, Ehara N, Kobori A, Nasu M, Okada Y, Furukawa Y. Clinical outcomes of medical therapy and timely operation in initially diagnosed type A aortic intramural hematoma: a 20-year experience. Circulation. 2009; 120 (suppl I): S292–S298.
Estrera A, Miller C III, Lee TY, De Rango P, Abdullah S, Walkes JC, Milewicz D, Safi H. Acute type A intramural hematoma: analysis of current management strategy. Circulation. 2009; 120 (suppl I): S287–S291.