Acute Type A Intramural Hematoma: The Less Deadly Acute Aortic Syndrome?

OBJECTIVE:To evaluate the short- and mid-term outcomes of surgically managed acute type A intramural hematoma (IMH) versus classic acute type A aortic dissection (ATAAD). METHODS:From 1996-February 2023, a total of 106 acute type A IMH patients and 795 classic ATAAD patients presented for open aortic repair at our institution. Data were obtained from the local Society of Thoracic Surgeons' Data Warehouse and medical chart review. RESULTS:Compared to the classic ATAAD group, the IMH group was older (65 vs. 59years, p<0.001) and more likely to be female (45% vs. 32%, p=0.005), with fewer comorbidities such as severe aortic insufficiency (5.0% vs. 25%, p<0.001), acute stroke (2.8% vs. 8.3%, p=0.05), acute renal failure (5.7% vs. 13%, p=0.04), and malperfusion syndrome (8.5% vs. 26%, p<0.001), but more cardiac tamponade (18% vs. 11%, p=0.03). The IMH group had less aortic root replacement (15% vs. 33%, p<0.001), Zone 2 arch replacements (9.4% vs. 18%, p=0.02), and shorter cross-clamp times (120minutes vs. 150minutes, p<0.001). The operative mortality was significantly lower in the IMH group (0.9% vs. 8.8%, p=0.005) and a multivariable regression model showed IMH to be protective, odds ratio of 0.11, p=0.03. The 10-year survival was similar between the two groups (65% vs. 61%, p=0.35). The hazard ratio of IMH for mid-term mortality after surgery was 0.73, p=0.12. CONCLUSIONS:Acute type A IMH could be treated with emergency open aortic repair with excellent short and mid-term outcomes.