• Dilated Aortic Root Associated with Higher Rates of Aortic Dissection at a Smaller Diameter: IRAD Registry

    Patients with modest dilation in the aortic root (AR) had acute type A aortic dissections (ATAD) at a significantly smaller diameter compared to patients with modestly dilated ascending aorta (AA), according to registry data.

    Asvin M. Ganapathi, MD, of Ohio State University Wexner Medical Center,  and colleagues reported these findings from the International Registry of Acute Aortic Dissection (IRAD) database in a paper published online Monday and in the May 17 issue of the Journal of the American College of Cardiology.

    IRAD is an international registry consisting of 42 referral centers throughout North America, Europe and Asia that enrolls patients with acute aortic dissection. For the current study, patients presenting with ATAD from May 1996 to October 2016 (n = 4,254) were screened, of whom 1,120 had measurements available for both the aortic root (AR) and supracoronary AA. Of these, patients with maximal aortic diameters (MAD) < 5.5 cm at the time of ATAD were included in the final analysis (n=667). Patients with connective tissue disorders, congenital bicuspid valve, familial thoracic aneurysm and dissection syndromes were excluded from the analysis.

    Patients were stratified into two groups by location of the largest proximal aortic segment, AR (n=137) and supracoronary AA (n=530), at the time of the ATAD. The mean age was 58.5 ± 13.0 years in the AR group and 63.2 ± 13.3 years in the supracoronary AA group. The majority of patients were male (AR 78.1% vs AA 64.7%), and a small proportion had a known history of aortic aneurysm (AR 10.3% vs. AA 10.1%). The most common presentation was chest pain. Moderate to severe aortic insufficiency was more common in the AR group vs AA group (35.3% vs 28.9%).

    There were slight differences in the operative characteristics among two groups, with a trend toward relatively frequent use of hypothermic circulatory arrest in the AA group and higher rate of concomitant coronary artery bypass graft and aortic root replacement in AR group. The study found that modestly dilated ARs (median MAD 4.6 cm [interquartile range {IQR}: 4.1-5.0 cm]) appears to dissect at a significantly smaller diameter compared to modestly dilated AAs (median MAD 4.8 cm [IQR: 4.4-5.1 cm], p<0.01). Postoperative outcomes were comparable between the groups. In-hospital/30-day mortality rates were 19.0% in the AR group and 17.5% in the AA group (p=0.70). The unadjusted long-term survival was also comparable between the groups (p=0.09).

    The key limitations of the study include that it was a retrospective analysis with the potential for bias; the cohort was largely from high-volume centers, so the results are not generalizable to other centers; and the validation of the measurements submitted to IRAD was not performed by a core lab. The authors concluded that approximately 20% of ATAD occurs in MAD < 5.5 cm, and these findings may have implications for future guidelines regarding management of aortic disease patients.

    In an accompanying editorial, Milind Y. Desai, MD, MBA, and Lars G. Svensson, MD, PhD, of Heart, Vascular, and Thoracic Institute, Cleveland Clinic, acknowledged the diligent efforts of the authors to exclude genetic mediated aortopathies. However, the editorialists stated that the study likely included some patients with unrecognized genetically triggered aortopathy given new mutations being rapidly discovered in these patients. They recommended to reinforce the strategies aimed at precision imaging and endorsed aortic cross-sectional area to-height ratio as a better method for quantifying risk of future aortic complications, particularly for the patients with dilated AR.

    Furthermore, they stressed the need for developing high-volume centers of excellence where such patients can be treated expeditiously using precision imaging with excellent outcomes.

    Sources:

    Ganapathi AM, Ranney DN, Peterson MD, et al. Location of Aortic Enlargement and Risk of Type A Dissection at Smaller Diameters. Location of Aortic Enlargement and Risk

    of Type A Dissection at Smaller Diameters. J Am Coll Cardiol 2022;79:1890–1897.

    Desai MY, Svensson LG. Toward a Precision Imaging-Driven Approach to Aortic Surgical Timing: Dissecting the Root of the Matter. J Am Coll Cardiol 2022;79:1898–1900.

    Image Credit: Olga – stock.adobe.com

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