False lumen thrombosis and aneurysmal transformation of the non-operated aorta after surgical treatment of proximal dissection

Background: One of the most feared long-term complications of surgical treatment of proximal aortic dissections is an aneurysm of the non-operated compartments of the aorta.Objective: To conduct a comparative analysis of different methods for surgical treatment of proximal aortic dissections in relation to false lumen thrombosis development in non-operated compartments.Methods: We conducted a simple observational retrospective multicenter study to study the effectiveness of the frozen elephant trunk technique compared with a standard surgical intervention (aggressive hemiarch anastomosis or total aortic arch replacement with a multibranched prosthesis). Our study included 101 patients grouped based on the method of treatment: group 1 for frozen elephant trunk (n = 31); group 2 for thoracic aorta reconstruction by the standard methods (control group, n = 70). Due to the retrospective nature of the study and the disparity of groups by certain characteristics, we used propensity score matching to increase the reliability of the results. All patient data were collected in the preoperative period, from the protocols of surgical interventions, in the postoperative and long-term periods (3-6 months, 1 year, 2 years, 3 years after surgery). All statistical calculations were conducted in the RStudio software, version 0.99.879 (RStudio Inc., Boston, USA).Results: The absence of false lumen thrombosis at the thoracic aorta level persisted after the surgical treatment in half of the patients in the control group (n = 13; 52%) and was not determined in the frozen elephant trunk group. Complete false lumen thrombosis at the thoracic aorta level (level of stent graft placement and distal to the diaphragm) was achieved in more than half of the patients in the frozen elephant trunk group and only in 3 (12%) control patients. Aneurysmal transformation of the non-operated aorta occurred in 12 (48%) patients from group 2 and was absent in group 1.Conclusion: The frozen elephant trunk technique reduces the frequency of aorto-related events to 0% within 3 years compared with the standard approach (32%, P < .005). Patients operated on for proximal aortic dissection using the frozen elephant trunk technique are significantly more likely to have false lumen thrombosis in the thoracic aorta (P = .004), significantly lower incidence of aneurysmal transformation or thoracic aorta growth rate of >5 mm per year in the long-term period (P = .016) compared with those who underwent the standard methods. Received 15 February 2023. Revised 31 July 2023. Accepted 4 August 2023. Funding: The study was carried out within the framework of the grant of the President of the Russian Federation НШ-5096.2022.3 (agreement No. 075-15-2022-823 dated 12.05.2022). Conflict of interest: The authors declare no conflict of interest. Contribution of the authorsConception and study design: A.M. Chernyavskiy, M.M. Lyashenko Data collection and analysis: M.M. Lyashenko, A.A. Shadanov, D.S. Panfilov, E.V. SkurikhinaStatistical analysis: M.M. LyashenkoDrafting the article: M.M. LyashenkoCritical revision of the article: A.M. Chernyavskiy, D.A. Sirota, B.N. KozlovFinal approval of the version to be published: A.M. Chernyavskiy, M.M. Lyashenko, D.A. Sirota, A.A. Shadanov, B.N. Kozlov, D.S. Panfilov, E.V. Skurikhina