Downstream thoracic endovascular aortic repair following zone 2, 100-mm stent graft frozen elephant trunk implantation

Hemodynamic changes for half cover left subclavian artery ostium during thoracic endovascular aortic repair

Purpose

Some clinicians use endografts to cover half the left subclavian artery (LSA) ostium to cure some cases with insufficient proximal landing zone (PLZ) in thoracic endovascular aortic repair (TEVAR) treatment. We used computational fluid dynamics (CFD) to study the hemodynamic changes in the LSA because they may cause acute thrombosis or arteriosclerosis.

Methods

The digital model of the aortic arch was established and named model A, which only included the supraarch branch of the LSA. By directly covering half of the LSA ostium, which was named as model B. All established models were imported into the Gambit grid division software for grid division and were subsequently imported into the Fluent software for hemodynamic numerical simulation and calculation to analyze the related changes in LSA hemodynamic parameters after stent implantation.

Results

Under the same aortic inlet flow, in model B, the local blood flow velocity of the LSA ostium increased and the whole blood flow velocity at the distal end decreased. The average wall shear stress (WSS) of the LSA was significantly decreased. Meanwhile there was an obvious turbulent flow in the LSA lumen, and the related blood flow state was disordered.

Conclusion

CFD research confirmed that the implantation of an endograft covering half the LSA ostium can cause obvious hemodynamic changes, which is likely to cause a long-term arteriosclerosis or acute thrombosis of the LSA, finally increasing the risk of stroke. Once this operation is performed in some specific clinical cases for simplicity and economy, it seems that we should actively antiplatelet and follow up regularly.

Frozen elephant trunk technique using hybrid grafts: 15-year outcomes from a single-centre experience

OBJECTIVES

The purpose of the study is to compare the short- and long-term outcomes of the frozen elephant trunk (FET) technique based on 2 different hybrid grafts implanted from January 2007 to July 2022.

METHODS

The study includes patients who underwent an elective or emergency FET procedure. Short-term, long-term mortality and freedom from thoracic endovascular aortic repair (TEVAR) were the primary end points. Analyses were carried out separately for the periods 2007-2012 and 2013-2022.

RESULTS

Of the 367 enrolled, 49.3% received E-Vita Open implantation and 50.7% received Thoraflex Hybrid implants. Overall mean age was 61 years [standard deviation (SD) = 11] and 80.7% were male. The average annual volume of FET procedures was 22.7 cases/year. Compared to E-Vita Open, patients implanted with Thoraflex Hybrid grafts were more likely to receive distal anastomosis in zone 2 (68.3% vs 11.6%, P < 0.001) with a shorter stent portion, mean = 103mm (SD = 11.3) vs mean = 149 mm (SD = 12.7; P < 0.001) and they underwent a reduced visceral ischaemia time, mean = 42.5 (SD = 14.2) vs mean= 61.0 (SD = 20.2) min, P < 0.001. In the period 2013-2022, overall survival at 1, 2 and 5 years was 74.8%, 72.5% and 63.2% for Thoraflex and 73.2%, 70.7% and 64.1% for E-Vita, without significant differences between groups (log-rank test = 0.01, P = 0.907). Overall freedom from TEVAR at 1, 2 and 5 years was 66.7%, 57.6% and 39.3% for Thoraflex and 79%, 69.7% and 66% for E-Vita, with significant differences between groups (log-rank test = 5.28, P = 0.029). In a competing risk analysis adjusted for chronic/residual aortic syndromes and stent diameter, the Thoraflex group was more likely to receive TEVAR during follow-up (subdistribution hazard ratio SHR = 2.12, 95% confidence interval 1.06-4.22).

CONCLUSIONS

The FET technique addresses acute and chronic arch disease with acceptable morbidity and mortality. Downstream endovascular reinterventions are very common during follow-up.

Retrospective investigation of >400 patients undergoing thoracic endovascular aortic repair with or without cerebrospinal fluid drainage

OBJECTIVES

The aim of this study was to analyse the risks and benefits of cerebrospinal fluid drainage (CSFD) placement in patients undergoing thoracic endovascular aortic repair.

METHODS

Between 2009 and 2020, 411 patients underwent thoracic endovascular aortic repair in 1 institution where 236 patients (57%) received a preoperative CSFD. Patient and outcome characteristics were retrospectively analysed and compared between patients with and without preoperative CSFD placement.

RESULTS

Preoperative CSFD was performed significantly more frequently in elective patients, especially those undergoing distal stent graft extension following frozen elephant trunk-stent placement (P < 0.001). Significantly fewer CSFD was placed in patients with acute aortic injury (P < 0.001). The incidence of permanent spinal cord ischaemia (SCI) was higher in patients without preoperative CSFD [10 patients (2%) vs 1 patient (0.2%), P = 0.001]. Postoperative CSFD was placed in 3 patients (0.7%). Severe CSFD-associated complications affected 2 patients (0.5%) namely, a subdural spinal haematoma causing permanent paraplegia in one of those 2 patients.

CONCLUSIONS

CSFS placement is associated with low procedural risk and can potentially help to prevent SCI. However, the SCI incidence is most likely also associated with other preoperative factors including the patient's haemodynamics. Hence, a general recommendation for placing a preoperative CSFD cannot be made when relying on the present evidence.

The Frozen Elephant Trunk Procedure Using New Russian Hybrid Prosthesis "Soft Elephant Trunk": the Early Experience

Aim      To present the first experience of performing the Frozen Elephant Trunk (FET) surgery in patients with thoracic aorta disease using a new Russian hybrid stent graft "Soft Elephant Trunk".Material and methods  Between 2014 and 2021, 170 patients with thoracic aortic disease underwent complete aortic arch replacement using the FET technique. In 70 of these cases (since June 2019), a hybrid graft "Soft Elephant Trunk" was used. A specific feature of this graft is the conical reduction of the radial force of nitinol crowns and the soft distal end without radial force. The study endpoints were early postoperative results, as well as the absence of reoperations on the aorta, absence of stent-graft-associated complications, including distal stent-graft-induced fenestration, and survival at a mid-term follow-up of up to 2.5 years.Results Interventions were performed in patients with A type aortic dissection (n=51; 72.9 %), type B aortic dissection (n=13; 18.6 %), and thoracoabdominal aortic aneurysm (TAAA) (n=6; 8.5 %). In 14 (20 %) of these cases, interventions were performed after a primary intervention on the proximal aorta. Acute aortic dissection was diagnosed in 17 (24.3 %) cases. Aortic root replacement was performed in 21 (30 %) cases, David procedure in 5 (7.2 %) cases, Bentall-DeBono procedure in 11 (15.7 %) cases, and supracoronary graft placement in 33 (47.1 %) cases. There were no cases of paraplegia or paraparesis. Respiratory insufficiency was observed in 8 (11.4%) cases. In one (1.4%) case, acute renal failure developed, which required renal replacement therapy. In-hospital mortality was 4.3 % (3 patients died). Mean follow-up duration was 9 [4.25; 16] months. Three-year survival was 94 % (95 % confidence interval, CI: 88-99.9) and absence of reoperation was 96.6 % (95 % CI: 90.1-100). There were no cases of distal stent-graft-induced fenestration in this group.Conclusion      The new hybrid graft, due to its specific structure, provides prevention of distal stent-graft-induced fenestration and, thereby, a stable long-term result. Using this stent-graft is effective in patients with thoracic aorta pathology undergoing the FET surgery. However, further studies are needed to determine potential advantages and disadvantages of this new hybrid graft, to obtain long-term results and accumulate experience.

Branched endovascular iliac artery repair using the Zenith® Branch Endovascular Iliac Bifurcation graft: outcomes and reinterventions in our retrospective cohort

Background

The aim of this retrospective cohort study was to analyze the outcomes and the need for reinterventions following branched iliac artery repair using the Zenith® Branch Endovascular Iliac Bifurcation (ZBIS; Cook Medical Europe LTD, Limerick, Ireland) graft.

Methods

Patient characteristics and follow-up data on 63 patients following branched iliac artery repair using the ZBIS device were evaluated and compared between patients with and without iliac reinterventions. A competing risk regression model was analyzed to identify independent predictors of reinterventions, and to predict the reintervention risk.

Results

ZBIS implantation's technical success rate was 100%, and we observed no in-hospital mortality. Internal iliac artery patency was 93% during a median [first quartile, third quartile] follow-up of 19 [5, 39] months. Thirty-two iliac reinterventions were performed in 23 patients (37%) after a mean time of 3.0 months (IQR: 0.4-6.8) (time to first reintervention). Endoleaks type I and II were the most common indication for reinterventions (n=14, 61%). The internal iliac artery's diameter [subdistribution hazard ratio (sHR): 1.046; P=0.0015] and a prior abdominal aortic intervention (sHR: 0.3331; P=0.0370) were identified as significant variables in the competing risk regression model for a reintervention. The risk for reintervention was 33% (95% CI: 20-46%), and 46% (95% CI: 28-63%) after 12 and 36 months, respectively.

Conclusions

Endovascular repair of degenerative iliac artery aneurysms with Zenith Branch Iliac Bifurcation device is a feasible and safe option. Perioperative morbidity and mortality are low with good graft patency rates. The risk for secondary iliac artery interventions is considerable and highlights the need for patients with iliac disease to undergo continuous follow-up in a dedicated vascular center.

Early endovascular intervention for unfavorable remodeling of the thoracic aorta after open surgery for acute DeBakey type I aortic dissection: study protocol for a multicenter, randomized, controlled trial

BACKGROUND

Total arch replacement with frozen elephant trunk has been developed with promising results for DeBakey type I aortic dissection. However, several problems, such as continuous perfusion of distal false lumen and unfavorable remodeling of distal aorta postoperatively, can seriously affect the long-term outcome. This trial aims to assess the effects of early minimally invasive endovascular repair on distal aortic remodeling and long-term clinical outcomes in patients with dominant false lumen and residual tears in the descending thoracic aorta after total arch replacement and frozen elephant trunk procedure.

METHODS

This is a protocol for a two-arm, parallel, multicenter, randomized controlled trial. A total of 154 eligible patients will be recruited from four hospitals in China and randomized on a 1:1 basis either to the experiment group (endovascular repair in addition to routine antihypertensive therapy) or the control group (routine antihypertensive therapy without early surgical treatment). The primary outcome will be the five-year all-cause mortality. The secondary outcomes will include re-intervention, ischemic symptoms, organ dysfunction, and stent-related adverse events.

DISCUSSION

If early minimally invasive endovascular repair could safely and effectively promote distal aortic remodeling and bring favorable long-term outcomes for patients with dominant false lumen and residual tears in the descending thoracic aorta after total arch replacement and frozen elephant trunk technique, it would improve the treatment strategy for DeBakey type I aortic dissection.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, CHiCTR2000030050. Registered on 11 March 2020.

Frozen Elephant Trunk Procedure and Risk for Distal Stent-Graft-Induced New Entries

The frozen elephant trunk (FET) procedure is known as an effective treatment option for patients with any aortic pathology involving the aortic arch. However, there is growing evidence that many patients often require secondary intended, expected, or unexpected aortic reinterventions during follow-up. In those with underlying aortic dissection pathology, a substantial risk for developing distal stent-graft-induced new entries (dSINEs) has been identified as one cause for secondary aortic reinterventions. dSINE can develop at any time after the FET procedure. Endovascular treatment is generally feasible and safe to close the newly formed entry with low procedural risk. Nevertheless, all patients need continuous follow-up after FET treatment, ideally in a specialized aortic outpatient clinic.

Endovascular reintervention after frozen elephant trunk: where is the evidence?

The introduction of the single-step hybrid frozen elephant trunk (FET) procedure for total arch replacement has revolutionized the field of aortovascular surgery. FET has proven to achieve excellent results in the repair of complex thoracic aorta pathologies. However, there remains a risk of reintervention post-FET for a variety of causes. This secondary intervention can either be performed endovascular, with thoracic endovascular aortic repair (TEVAR), or via open surgery. Multiple FET hybrid prosthesis are commercially available, each requiring different rates of endovascular reintervention. The current review will focus on providing an overview of the reintervention rates for main causes in relation to the FET grafts on the market. In addition, strategies to prevent reintervention will be highlighted. A comprehensive literature search was conducted on multiple electronic databases including PubMed, Ovid, Scopus and Embase to highlight the evidence in the literature on endovascular reintervention after FET. The main causes for secondary intervention are distal stent graft-induced new entry (dSINE), endoleak and negative aortic remodeling, and to a much lesser extent, graft kinking and aorto-esophageal fistulae. In addition, it is clear that the Thoraflex Hybrid (Terumo Aortic, Inchinnan, UK) is the superior FET device, showing excellent reintervention rates for all the above causes. Interestingly, the choice of FET device as well as its size and length can help prevent the need for reintervention. The FET procedure is indeed associated with excellent clinical outcomes, however, the need for reintervention may still arise. Importantly, the Thoraflex Hybrid prosthesis has shown excellent results when it comes to endovascular reintervention. Finally, several strategies exist that can prevent reintervention.

Postoperative In-Stent Thrombus Formation Following Frozen Elephant Trunk Total Arch Repair

Objectives

Our aim was to investigate the occurrence and clinical consequence of postoperative in-stent thrombus formation following the frozen elephant trunk (FET) procedure.

Methods

Postoperative computed tomography angiography (CTA) scans of all 304 patients following the FET procedure between 04/2014 and 11/2021 were analysed retrospectively. Thrombus size and location were assessed in multiplanar reconstruction using IMPAX EE (Agfa HealthCare N.V., Morstel, Belgium) software. Patients’ characteristics and clinical outcomes were evaluated between patients with and without thrombus formation.

Results

During the study period, we detected a new postoperative in-stent thrombus in 19 patients (6%). These patients were significantly older (p = 0.009), predominantly female (p = 0.002) and were more commonly treated for aortic aneurysms (p = 0.001). In 15 patients (79%), the thrombi were located in the distal half of the FET stent-graft. Thrombus size was 18.9 mm (first quartile: 12.1; third quartile: 33.2). Distal embolisation occurred in 4 patients (21%) causing one in-hospital death caused by severe visceral ischaemia. Therapeutic anticoagulation was initiated in all patients. Overstenting with a conventional stent-graft placed within the FET stent-graft was the treatment in 2 patients (11%). Outcomes were comparable both groups. Female sex (p = 0.005; OR: 4.289) and an aortic aneurysm (p = 0.023; OR: 5.198) were identified as significant predictors for thrombus development.

Conclusion

Postoperative new thrombus formation within the FET stent-graft is a new, rare, but clinically highly relevant event. The embolisation of these thrombi can result in dismal postoperative outcomes. More research is therefore required to better identify patients at risk and improve perioperative treatment.

Prediction Nomogram for Postoperative 30-Day Mortality in Acute Type A Aortic Dissection Patients Receiving Total Aortic Arch Replacement With Frozen Elephant Trunk Technique

Objective

To develop and validate a nomogram model to predict postoperative 30-day mortality in acute type A aortic dissection patients receiving total aortic arch replacement with frozen elephant trunk technique.

Method

Clinical data on 1,156 consecutive acute type A aortic dissection patients who got total aortic arch replacement using the frozen elephant trunk technique was collected from January 2010 to December 2020. These patients were divided into training and testing cohorts at random with a ratio of 7:3. To predict postoperative 30-day mortality, a nomogram was established in the training set using the logistic regression model. The novel nomogram was then validated in the testing set. The nomogram's calibration and discrimination were evaluated. In addition, we created four machine learning prediction models in the training set. In terms of calibration and discrimination, the nomogram was compared to these machine learning models in testing set.

Results

Left ventricular end-diastolic diameter <45 mm, estimated glomerular filtration rate <50 ml/min/1.73 m², persistent abdominal pain, radiological celiac trunk malperfusion, concomitant coronary artery bypass grafting and cardiopulmonary bypass time >4 h were independent predictors of the 30-day mortality. The nomogram based on these 6 predictors manifested satisfying calibration and discrimination. In testing set, the nomogram outperformed the other 4 machine learning models.

Conclusion

The novel nomogram is a simple and effective tool to predict 30-day mortality rate for acute type A aortic dissection patients undergoing total aortic arch replacement with frozen elephant trunk technique.

Predictive factors of distal stent graft-induced new entry after frozen elephant trunk procedure for aortic dissection

OBJECTIVES

The incidence rate of distal stent graft-induced new entry after frozen elephant trunk technique for aortic dissection remains controversial. The aim of this study was to investigate the incidence and seek the clinical and anatomical predictive factors.

METHODS

This study is a retrospective multicenter evaluation of complications including distal stent graft-induced new entry, aortic events, and re-intervention after the frozen elephant trunk procedure for aortic dissection.

RESULTS

Our cohort included total 177 consecutive patients who underwent the frozen elephant trunk procedure for acute and chronic aortic dissection at five centers in Japan from May 2014 to March 2021. The incidence rate of distal stent graft-induced new entry was 14.1% (25/177 patients). The cumulative incidence of d-SINE was 7.1%, 12.4%, 21.4% after 12, 36, and 60 months, respectively. Distal stent graft-induced new entry was not associated with mid-term survival rate. After competing risk regression analysis, onset time > 48 hours (subdistribution hazard ratio, 3.80; 95% confidence interval, 1.13-12.79; P=0.031) was detected as an independent predictor.

CONCLUSIONS

Awareness that there is a relatively higher incidence of distal stent graft-induced new entry after frozen elephant trunk procedures is important. Non-hyperacute phase was detected as an independent risk factor. Preemptive endovascular repair may be appropriate to protect new entry in high-risk patients.

Distal Aortic Failure Following the Frozen Elephant Trunk Procedure for Aortic Dissection

Background

Aim of this study was to report and to identify risk factors for distal aortic failure following aortic arch replacement via the frozen elephant trunk (FET) procedure.

Methods

One hundred eighty-six consecutive patients underwent the FET procedure for acute and chronic aortic dissection. Our cohort was divided into patients with and without distal aortic failure. Distal aortic failure was defined as: (I) distal aortic reintervention, (II) aortic diameter dilatation to ≥ 6 cm or > 5 mm growth within 6 months, (III) development of a distal stent-graft-induced new entry (dSINE) and/or (IV) aortic-related death. Preoperative, intraoperative, postoperative and aortic morphological data were analyzed.

Results

Distal aortic failure occurred in 88 (47.3%) patients. Forty-six (24.7%) required a distal reintervention, aortic diameter dilatation was observed in 9 (4.8%) patients, a dSINE occurred in 22 (11.8%) patients and 11 (6.4%) suffered an aortic-related death. We found no difference in the number of communications between true and false lumen (p = 0.25) but there were significantly more communications between Ishimaru zone 6–8 in the distal aortic failure group (p = 0.01). The volume of the thoracic descending aorta measured preoperatively and postoperatively within 36 months afterward was significantly larger in patients suffering distal aortic failure (p < 0.001; p = 0.011). Acute aortic dissection (SHR 2.111; p = 0.007), preoperative maximum descending aortic diameter (SHR 1.029; p = 0.018) and preoperative maximum aortic diameter at the level of the diaphragm (SHR 1.041; p = 0.012) were identified as risk factors for distal aortic failure.

Conclusion

The incidence and risk of distal aortic failure following the FET procedure is high. Especially those patients with more acute and more extensive aortic dissections or larger preoperative descending aortic diameters carry a substantially higher risk of developing distal aortic failure. The prospective of the FET technique as a single-step treatment for aortic dissection seems low and follow-up in dedicated aortic centers is therefore paramount.

Downstream thoracic endovascular aortic repair following the frozen elephant trunk procedure

The frozen elephant trunk technique has become a well-established treatment option for patients presenting all thoracic aortic pathologies including acute and chronic dissection, aortic aneurysms and even penetrating aortic ulcers involving the aortic arch and descending aorta. Nevertheless, there is a significant incidence of and risk for distal aortic reinterventions after the frozen elephant trunk. Indications mainly include a planned staged approach, diameter progression of downstream aortic segments and the development of distal stent-graft induced new entries (dSINEs). Endovascular stent-graft extension through conventional thoracic endovascular aortic repair (TEVAR) is a relatively simple and safe method to address any pathologies in the remaining descending thoracic aorta up to the level of the coeliac trunk. In fact, the frozen elephant trunk stent-graft provides an ideal proximal landing zone for any endovascular stent-graft extension. Postoperative outcomes are very promising with very low reported in-hospital mortality and morbidity. In case this 2-staged-approach fails to stabilize the remaining aorta, a 3-step procedure, namely open thoracoabdominal aortic replacement, is simplified because the anastomosis site has moved distally. Follow-up of all patients, following frozen elephant trunk implantation or distal stent-graft extension, is mandatory, ideally in an outpatient clinic dedicated to the aorta in order to identify disease progression or to detect any complications as soon as possible.