Treatment with transfemoral bare-metal stent of residual aortic arch dissection after surgical repair of acute type an aortic dissection

Is TEVAR an Effective Approach to Prevent Complications after Surgery for Aortic Dissection Type A? A Systematic Review

Introduction: A residual false lumen after treatment for Aortic Dissection type A (AD) has been associated with early complications, such as A malperfusion or rupture and mid-term or delayed complications, such as aneurysm formation or dissection expansion. Thoracic Endovascular Aortic Repair (TEVAR) is considered an effective solution by several surgical teams to prevent future complications. In this systematic review, all published data regarding the implementation of TEVAR after previous treatment for AD were collected in order to investigate indications, methods, clinical outcomes and aortic remodeling in these patients. Methods: The aim of this study was to investigate the indications, the methods and the efficacy of TEVAR usage after surgical treatment of AD. Data for this study were collected from four widely used medical databases (MEDLINE, SCIENCE DIRECT, GOOGLE SCHOLAR, OVID). All the results for each database were recorded and were analyzed with a systematic method. Techniques and clinical outcomes were investigated. Aortic remodeling was evaluated based on the following parameters in these studies: aortic diameter, true lumen diameter, false lumen diameter, false lumen thrombosis and false lumen patency. Results: The results obtained from the search among all databases comprised 1410 articles and of these articles 9 were included in the review. The majority of the studies were retrospective (seven out of nine studies), while no study was randomized. The total number of patients was 157 and 133 of them (84.7% of patients) were treated with TEVAR in zone 3 without extension below the diaphragm intraoperatively. Among 142 patients, the calculated mortality rate was 12.7% (18 of 142 patients), with 2.8% (4 of 142 patients) presenting with stroke. The percentage of patients with total or partial thrombosis combined was 65.9% (62 patients in a population of 92). The reintervention rate was 18.7%. Conclusions: TEVAR after AD surgery is an approach usually chosen in clinical practice, but the criteria of its usage are uncertain. This method is safe and enhances aortic remodeling with an acceptable reintervention rate. Definite guidelines in this field should be created in order to delineate whether TEVAR after AD surgery is beneficial as a preventive measure to aorta-related complications and to decide under which criteria this approach should be chosen.

Bare Stent Fracture After TEVAR With the Modified Restrictive Bare Stent (RBS) Technique in Type B Aortic Dissections

PURPOSE

The aim was to assess the mid-term aortic remodeling and bare-metal stent (BMS) integrity of the restricted bare stent (RBS) technique reconstruction in aortic dissections.

MATERIALS AND METHODS

This retrospective cohort study included prospectively collected patients treated with the modified RBS technique between 2017 and 2020. The preoperative, postoperative, and last follow-up computed tomographic (CT) scans were analyzed in the centerline at the mid-descending, celiac trunk (CeT), and the mid-abdominal levels for false lumen (FL) patency, aortic diameter, and true lumen (TL) diameter changes. Bare-metal stent integrity was assessed in the 3-dimensional multiplanar reformats.

RESULTS

The median follow-up of the cohort (n=17) was 26 (11, 45) months. The procedure was mainly performed with the Relay NBS endograft (15/17; 88%) + E-XL BMS (17/17; 100%). Postoperative mortality, paraplegia, stroke, renovisceral vessel loss, and type I and III endoleaks were not observed. BMS fractured in 6 patients (6/17; 36%), damaged the dissection flap in 4/17 (24%), and led to the reperfusion of the FL and re-interventions with TEVAR (4/17; 24%). Two patients without FL reperfusion showed stable CT follow-ups 13 and 17 months after the fracture diagnosis. The TL expansion was seen at all landmarks and peaked in the thoracic aorta (+10; 6, 15; p<0.001). The FL thrombosis after modified RBS was only relevant in the thoracic aorta (p<0.001) and at CeT (p=0.003). The aortic diameter was stable in the thoracic aorta and increased at distal landmarks (CeT [+5; 1, 10; p=0.001]; mid-abdominal [+3; 1, 5; p=0.004]).

CONCLUSION

The modified RBS technique could not stop aortic growth below the diaphragm and prevent new membrane rupture due to the fractures of the BMS and consecutive flap damage with the reperfusion of the FL.

CLINICAL IMPACT

The treatment of complicated type B aortic dissections with TEVAR has become a standard. Particularly, patients with true lumen collapse and malperfusion may benefit from a more aggressive treatment strategy including proximal TEVAR and distal bare-metal stent implantation to re-open the true lumen and to prevent distal stent-induced new entry. However, this study reports the challenges of this approach with a high rate of bare-metal stent fractures during the follow-up. The fractures that occurred at the site of vertical nitinol bridges led to the dissection membrane ruptures and the reperfusion of the false lumen with consecutive dilatation. A close follow-up is mandatory to detect this complication and to treat the patients with TEVAR extension.

An Integrated Approach for Treatment of Acute Type A Aortic Dissection

Background and objective: We reviewed a single-institution experience to verify the impact of surgery during different time intervals on early and late results in the treatment of patients with type A acute aortic dissection (A-AAD). Materials and Methods: From 2004 to 2021, a total of 258 patients underwent repair of A-AAD; patients were equally distributed among three periods: 2004-2010 (Era 1, n = 90), 2011-2016 (Era 2, n = 87), and 2017-2021 (Era 3, n = 81). The primary end-point was to assess whether through the years changes in indications, surgical strategies and techniques and increasing experience have influenced early and late outcomes of A-AAD repair. Results: Axillary artery cannulation was almost routinely used in Eras 2 (86%) and 3 (91%) while one femoral artery was mainly cannulated in Era 1 (91%) (p < 0.01). Retrograde cerebral perfusion was predominantly used in Era 1 (60%) while antegrade cerebral perfusion was preferred in Eras 2 (94%,) and 3 (100%); (p < 0.01). There was a significant increase of arch replacement procedures from Era 1 (11%) to Eras 2 (33%) and 3 (48%) (p < 0.01). A frozen elephant trunk was mainly performed in Era 3. Hospital mortality was 13% in Era 1, 11% in Era 2, and 4% in Era 3 (p = 0.07). Actuarial survival at 3 years is 74%, in Era 1, 78% in Era 2, and 89% in Era 3 (p = 0.05). Conclusions: With increasing experience and a more aggressive approach, including total arch replacement, repair of A-AAD can be performed with low operative mortality in many patients. Patient care and treatment by a specific team organization allows a faster diagnosis and referral for surgery allowing to further improve early and late outcomes.

Role of proximal and distal tear size ratio in hemodynamic change of acute type A aortic dissection

Background

Acute type A aortic dissection (ATAAD) is a life-threatening disease. The aim of this study was to examine the role of tear size in the hemodynamic change and help improve the treatment level of this extremely dangerous disease.

Methods

A total of 120 ATAAD patients treated in our institution from November 2014 to December 2016 were divided into three groups according to proximal and distal tear size ratio (PDTSR). There were 35 patients in group A (PDTSR ≥2:1), 44 patients in group B (1:2< PDTSR <2:1), and 41 patients in Group C (PDTSR ≤1:2). Three computational fluid dynamics (CFD) models with different PDTSRs were established to investigate the hemodynamic difference in the three groups.

Results

The mean age (± SD) of the 120 patients included in this study was 47.7±10.1 years. Patients in Group A had a significantly larger proximal tear size (219.1±76.5 vs. 127.7±70.1 vs. 75.7±49.7 mm²; P<0.001). The mortality of the patients in group A was significantly higher than those in group B and group C in the acute phase (37.1% vs. 2.3% vs. 2.4%, respectively; P<0.001). A proximal tear larger than a distal tear was found to be significantly associated with preoperative death in logistic regression analysis (odds ratio: 15.89; 95% confidence interval, 2.702-93.477; P=0.002).

Conclusions

A proximal tear larger than a distal tear was associated with a significantly high-pressure difference between false and true lumens and more blood flow into the false lumen. In such cases, patients would experience extremely high mortality and morbidity.

Modeling Approach for An Aortic Dissection with Endovascular Stenting

Repair of dissected aorta requires remodeling the structure of the media. Modeling approaches specific to endovascular stenting for aortic dissection have been reported. We created a goat model of descending thoracic aortic dissection and reproduced its morphological characteristics in a mock circulatory system. The purpose of this study was to examine a newly developed aortic stent which was capable of installing to the aortic dissected lesion for biomedical hemodynamics point of view. In this study, we examined the changes in hemodynamics of dissected lesions and the amelioration by endovascular stent intervention. Firstly, we performed animal experiments with the dissected aorta and examined the effects of stenting on volumetric changes in the false lumen. Secondly, we made several types of 3-D stereolithographic dissected aortic models with silicone rubber membrane between the false and the true lumens. Then, the hemodynamic characteristics in each model were evaluated in the pulsatile flow conditions in a mock circulatory system. These modelling approaches enabled the quantitative examination of post-therapeutic effects of stenting followed by elucidating of hemodynamic changes in the vicinity of stents, which may follow the management of clinical amelioration of interventional treatment with aortic stenting.Clinical Relevance- This study represents a modelling approach of the dissected aorta for endovascular intervention using stenting followed by the examination of false lumen volumetric changes resulting in the deterioration of pressure increase in diseased lesions.