Structured Abstract
Background
Patients with Stanford type B aortic dissections (AD) are at risk of long-term disease progression and late complications. The aim of this study was to evaluate the natural course and evolution of acute type B AD and intramural hematomas (IMH) in patients who presented without complications during their initial hospital admission and who were treated with optimal medical management (MM).
Methods
Databases from two aortic centers in Europe and the US were used to identify 136 patients with acute type B AD (n= 92) and acute type B IMH (n= 44) who presented without complications during their index admission and were treated with MM. Computed tomography (CT) angiography scans were available at onset (≤ 14 days) and during follow-up for those patients. Relevant data, including evidence of adverse events during follow-up (AE; defined according to current guidelines), were retrieved from medical records and by reviewing CT scan images. Aortic diameters were measured using dedicated 3D software.
Results
The 1-, 2- and 5-year event-free survival rates of patients with type B AD were 84.3% (95% CI: 74.4 – 90.6), 75.4% (95% CI: 64.0 – 83.7) and 62.6% (95% CI: 68.9 – 73.6), respectively. Corresponding estimates for IMH were 76.5% (95% CI: 57.8 – 87.8), 76.5% (95% CI: 57.8 – 87.8) and 68.9% (95% CI: 45.2 – 83.9), respectively. In patients with type B AD, risk of an adverse event increased with aortic growth within the first six months after onset. A diameter increase of 5 mm in the first half year was associated with a relative risk for AE of 2.29 (95% CI: 1.70–3.09) compared with the median 6 months growth of 2.4 mm. In about 60% of IMH patients the abnormality resolved within 12 months and in the patients with non-resolving IMH, risk of an adverse event was highest in the first year after onset and remained stable thereafter.
Conclusions
More than one-third of patients with initially uncomplicated type B AD suffer an AE under MM within 5 years of initial diagnosis. In patients with non-resolving IMH, most adverse events are observed in the first year after onset. In patients with type B AD an early aortic growth is associated with a higher risk of AE.