Intervention for residual dissection in its early phase—comment on a prospective follow-up study after type A aortic dissection repair: a high rate of distal aneurysmal evolution and reinterventions

With advances in medical device technology and perioperative care, early operative outcomes of type A aortic dissection (TAAD) has improved. Along with this, the number of patients who require additional procedures for the residual aortic dissection has also been increasing. Conventional extensive aortic arch repair or hybrid aortic arch repair may improve long-term outcomes of TAAD [1, 2]. However, ascending aorta or hemiarch repair offers several advantages over aortic arch repair: it shortens myocardial ischaemia time, cardiopulmonary bypass time, and operation time, and it decreases intraoperative blood loss and the transfusion requirement [3]. Prolonged cardiopulmonary bypass and long operation time increase the incidence of postoperative complications. The rate at which such extensive aortic arch repair is implemented continues to increase, but ascending aorta repair and hemiarch repair remain standard options for the treatment of TAAD, especially for high-risk or elderly patients. Both ascending aorta repair and hemiarch repair are associated with the presence of a residual patent false lumen in the downstream aorta. A dissecting aorta with a patent false lumen frequently enlarges during the follow-up period. An enlarged downstream aorta is a problem that aortic surgeons face and needs to address promptly. Gaudry et al. [4], authors of ‘Results of a prospective follow-up study after type A aortic dissection repair: a high rate of distal aneurysmal evolution and reinterventions’, are to be congratulated. They analysed change in the aortic diameter observed in patients with residual aortic dissection following TAAD repair and identified risk factors for dissection-related events (vascular events). Surprisingly, of 121 hospital survivors with residual aortic dissection after the initial aortic repair for TAAD, only 17 were excluded from the study, and that was because they did not live close to the centre where they had been treated and were thus followed up by local cardiologists. The remaining 104 patients (86.0%) underwent clinical and radiological follow-up at the aortic centre where the initial repair had been done. The follow-up examinations were performed at 3, 6 and 12 months. Although most aortic surgeons recognize the importance of regular radiographic check-ups during the subacute and chronic phases of TAAD, hospitals’ postoperative follow-up practices often vary. For example, an aortic centre may focus on acute-phase treatment, with outpatient follow-up being carried out at a local cardiovascular hospital. The Gaudry et al. study showed that systematic, close follow-up at an aortic centre may improve long-term outcomes of patients with TAAD. Remote image transfer between patients’ local hospitals and aortic centres may facilitate close follow-up, even for patients living in distant areas or outside the country. The strength of the Gaudry et al. study lies in high-quality imaging data used for analysis. All patients included in the study underwent postoperative and follow-up triple-phase CT examinations. Notably, precise measurement of the principal entry tear and residual entry tear in the downstream aorta by means of 3D imaging software increased the scientific worth of the study by providing detailed morphological information about the dissecting aorta. The study revealed a high incidence of dissection-related events (46.1% [48/104]), which might have been due to the fact that none of the patients underwent extensive aortic arch repair or hybrid aortic arch repair and that patients without residual aortic dissection were excluded from the study. In general, efficacy of thoracic endovascular aortic repair for a greatly enlarged dissecting aorta is limited. The standard treatment for such an enlarged dissecting aorta is open aortic repair. However, open aortic repair poses a risk of postoperative neurological and respiratory complications and is thus usually performed in physically active non-elderly patients. As advocated by Gaudry et al. [4], and in light of these factors, aggressive early-phase intervention for residual aortic dissection should be considered for patients whose descending aorta is expected to enlarge. Thoracic endovascular aortic repair for acute or subacute aortic dissection may stimulate positive aortic remodelling via rapid expansion of the true lumen and promote false lumen thrombosis. Although a large-scale multicentre study is needed for validation, the Gaudry et al. findings argue for pre-emptive aortic intervention against residual aortic dissection in patients with TAAD.