Improved Remodeling With TEVAR and Distal Bare-Metal Stent in Acute Complicated Type B Dissection

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.

LONG-TERM OUTCOMES AND RISK FACTORS ANALYSIS FOR PATIENTS UNDERGOING THORACIC ENDOVASCULAR AORTA REPAIR (TEVAR), ACCORDING TO THE AORTIC PATHOLOGIES

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has become a standard treatment for acute and chronic thoracic aorta diseases. We analysed long-term outcomes and risk factors of TEVAR procedures according to the aortic pathology.

METHODS

Demographics, indications, technical details, and outcomes of patients undergoing TEVAR procedures in our institutions were prospectively collected and retrospectively analyzed. Overall survival was determined using Kaplan-Meier methods while Log-rank tests were used to compare the survival between groups. Cox regression analysis was used to identify risk factors.

RESULTS

Between June 2002 and April 2020, 116 patients underwent TEVAR for different thoracic aorta diseases. Among them, 47 patients (41%) underwent TEVAR for aneurysmatic aortic disease, 26 (22%) for type-B aortic dissection, 23 (20%) for penetrating aortic ulcer, 11 (9%) after previous type-A dissection treatment and 9 (8%) for traumatic aortic injury. Patients with post-traumatic aortic injury were younger (p<0.01), with less hypertension (p<0.01), diabetes (p<0.01) and prior cardiac surgery (p<0.01). Survival was different based on indication for TEVAR (log rank 0.024). Patients after previous type-A dissection treatment had the worst survival rate (50% at 5 years) while survival for aneurysmatic aortic disease was 55% at 5 years. No late death occurred in the traumatic group. Cox-regression model identified independent predictors for mortality: age (HR 1.05, 95% CI 1.01-1.09, p= 0.006), male gender (HR 3.2, 95% CI 1.1-9.2, p=0.028), moderate COPD (HR 2.1, 95% CI 1.02-4.55, p=0.043), previous cardiac surgery (HR 2.1, 95% CI 1.008-4.5, p=0.048), and treatment indication for aneurysm (HR 2.6, 95% CI 1.2-5.2, p=0.008).

CONCLUSIONS

TEVAR is a safe and effective procedure with excellent long-term results in case of traumatic aortic injury. The overall long-term survival is affected by aortic pathology, associated comorbidities, gender and previous cardiac surgery.

Changing Management of Type B Aortic Dissections

The purpose of this manuscript is to review recent trends in the management of acute type B aortic dissection. Due to its efficacy and low morbidity, thoracic endografting has rapidly been adopted as the treatment of choice for most patients with malperfusion or rupture as a consequence of acute aortic dissection. This technology is increasingly applied to patients without rupture or malperfusion, so-called "uncomplicated" dissections, to reduce the incidence of late aneurysmal degeneration in the ungrafted segments of the thoracoabdominal aorta. A variety of techniques have been proposed, including intentional rupture of the dissection membrane to obliterate the false lumen as well as the candy-plug technique to eliminate retrograde flow in the false lumen.

Extended Stent Coverage Decreases Distal Aortic Segmental Enlargement After the Endovascular Repair of Acute Complicated Type B Aortic Dissection: A Multi-Center Retrospective Study of 814 Patients

PURPOSE

This study aimed to investigate the effect of distal aortic segmental enlargement (DASE) after thoracic endovascular aortic repair for complicated type B aortic dissection (cTBAD).

MATERIALS AND METHODS

From March 2003 to October 2018, 814 patients with acute cTBAD from 5 medical centers were retrospectively identified. DASE is indicated as the enlargement of distal aortic segmental volume ≥1.6 fold of the preoperative volume compared with the most recent postoperative computed tomography angiography (CTA) scan. Of these patients, 635 (78%) were identified as non-DASE, and 179 (22%) were identified as DASE. Competing risk analysis was performed to compare late death and distal aortic reintervention between the groups. The morphological variables and false lumen thrombosis at 7 aortic levels were measured based on the preoperative CTA and the most recent CTA. Univariate and multivariate Cox regression analyses were used to assess the independent predictors of DASE.

RESULTS

The mean follow-up time of the entire cohort was 5.6 years (interquartile range: 2.4-8.3 years). There were total of 208 late deaths, including 94 (14.8%) deaths in non-DASE group versus 114 (63.7%) deaths in the DASE group. Distal aortic reintervention was observed in 89 patients, with 43(6.7%) in the non-DASE group versus 46 (25.7%) in the DASE group. The cumulative incidence of late death and distal aortic reintervention were significantly higher in the DASE than in the non-DASE group (p<0.001). In morphological analysis, significant incomplete false lumen thrombosis was observed in all distal aortic segments above the aortic level of celiac artery (p<0.01). According to multivariate analysis, the Marfan syndrome, stent coverage to the level of diaphragm and the level of celiac artery were independent predictors of the DASE (p<0.001). Patients with extended stent coverage to the level of celiac artery have shown a lower incidence of DASE (p<0.010).

CONCLUSION

Compared with the non-DASE group, patients with DASE demonstrated a higher rate of late death and distal aortic reintervention. For the cTBAD population, extended stent-graft coverage to the aortic section between diaphragm and celiac artery might serve as a "cost-efficient" cutoff point aiming to reduce the risk of DASE.

Technique-Based Evaluation of Clinical Outcomes and Aortic Remodelling Following TEVAR in Acute and Subacute Type B Aortic Dissection

INTRODUCTION

To evaluate the clinical outcomes and aortic remodelling rates following thoracic endovascular aortic repair (TEVAR) for acute or subacute type B aortic dissection (TBAD) based on technique.

MATERIAL AND METHODS

All TEVARs for acute/subacute TBAD between 01/01/2008 and 01/06/2020 were included. TEVARS were grouped by technique (TEVAR only, PETTICOAT and STABILISE). Aortic remodelling was assessed at three aortic levels on follow-up CT. Thirty-day technical/clinical success rates, re-intervention rates and complications were recorded.

RESULTS

A total of 29 patients were included. The median age was 55 years (31-82). The median duration from initial presentation to TEVAR was 7 days (0-84). Intra-procedural complications included one aortic rupture from balloon moulding in a STABILISE case. Thirty-day mortality, stroke, spinal cord ischaemia and visceral ischaemia were 3% (n = 1), 3% (n = 1), 3% (n = 1) and 3% (n = 1), respectively. (All occurred in acute TBAD.) Overall survival was 50.5 months (18-115). Median follow-up was 31 months (1-115). Six patients (21%) required re-intervention, with a median time of 5 months (5-46) from first TEVAR. Overall complete aortic remodelling rates were: 89% at the proximal descending thoracic aorta, 78% at the distal thoracic aorta and 50% at the infra-renal abdominal aorta. At the infra-renal aorta, the STABILISE group (n = 11) had a higher complete aortic remodelling rate (82%) compared to TEVAR alone (n = 12) (20%).

CONCLUSION

Endovascular intervention for acute and subacute TBAD is safe with a high rate of technical success. STABILISE results in higher aortic remodelling at the infra-renal aorta (82%) compared to TEVAR alone (20%) but risks aortic rupture from balloon moulding.