Commentary on “Mid-term Outcomes and Aortic Remodelling After TEVR for Acute, Sub-acute and Chronic Aortic Dissection: The Virtue Registry”

Abstract

designed to follow patients over a 3-year period in order to study the mid-term efficacy of TEVR for Type B dissection. 3 The most important finding from VIRTUE was that the dissected aorta retained its plasticity after the classical 2week window had elapsed following onset of symptoms. This is novel and suggests that patients with sub-acute dissection may also benefit from TEVR through aortic remodeling, thereby avoiding the risks of aneurysmal degeneration. A second message was the low dissectionrelated mortality following TEVR at 3 years. This is important, as it is still unknown whether TEVR offers similar protection (from late aortic related mortality) as open surgery. 4 The third important finding was the relatively high rate of reintervention at 3 years (especially in the chronic dissection group), where eight out of 26 (31%) of patients with a chronic dissection required distal extension after their primary TEVR. In response, the VIRTUE authors observed that patients with chronic Type B dissections might require more extensive coverage to start with. However, there is no compelling evidence that simple TEVR extension confers any late benefit in patients with chronic dissection. In our opinion, the only good reason to treat a chronic dissection is where there is evidence of degeneration in association with the development of a postdissection aneurysm. As most post-dissection aneurysms involve the thoraco-abdominal aorta, it does not seem logical to expect exclusion of the aneurysm to succeed without proper distal sealing. One durable solution might be to use fenestrated/branched grafts to achieve distal sealing, with preservation of the visceral vessels. 5 NotwithstandingtheseimportantmessagesfromVIRTUE,it isalso importanttobecarefulregardingoverinterpretationof its findings. This was a prospective, non-randomized, multicenterEuropeanClinicalRegistry,whichincluded100patients with Type B aortic dissection treated using the Medtronic Valiant thoracic stent-graft. The design of the Registry suggests a commercial purpose in order to demonstrate the superiorityoftheMedtronicthoracicstent-graft.Unfortunately, the sample size wastoo small to enable meaningful statistical analysis, especially for comparisons among the three temporal groups (acute, sub-acute, and chronic). In addition, patients were not enrolled consecutively, and there was no record of how many patients were treated in each center but not included in the Registry and why. The need for interventionwasattheinvestigators’discretion,withlittleinformation provided regarding the precise indication in sub-acute and chronic dissections. Finally, because only the Valiant stentgraft was used, one should be careful not to generalize the results to other stent-grafts. These limitations, plus a regret that the investigators were unable to persuade Medtronic to fund follow-up to 5 years, were identified during the manuscript review process. Where possible, the authors addressed these concerns, but there are important lessons to be learned for those planning similar registries in the future. Registries will continue to play an important role in evaluating new endovascular technologies. However, those involved in their planning should include provision for larger numbers, longer-term follow-up (i.e., 5 years) and a record must be maintained of those who were not included within the Registry. Otherwise, the outcomes may only be representative of a relatively small cohort of carefully selected patients and not generalizable to routine clinical practice.