Thoracic Stent Graft Implantation Research Articles

Development of modified laser Doppler flowmetry device for real-time monitoring of esophageal mucosal blood flow: a preclinical assessment with an animal model.

This study aimed to modify a laser Doppler flowmeter designed and assembled at our institute. After measuring sensitivity evaluation in ex vivo experiments, we confirmed the efficacy of this new device for monitoring real-time esophageal mucosal blood flow changes after thoracic stent graft implantation by simulating various clinical situations in an animal model. Thoracic stent graft implantation was performed in a swine model (n = 8). Esophageal mucosal blood flow decreased significantly from baseline (34.1 ± 18.8ml/min/100g vs. 16.7 ± 6.6ml/min/100g, P < 0.05) in the lower esophagus (Th6-Th8) where the stent graft covered the aorta. In the hemorrhagic shock model (shock index ≥ 1.0), esophageal mucosal blood flow showed a remarkable change from baseline in the upper esophagus (Th1-Th3), where the stent graft did not cover the aorta (20.8 ± 9.8ml/min/100g vs. 12.9 ± 8.6ml/min/100g, P < 0.01); however, it returned to the baseline value within a 30-min period. Mucosal blood flow remained stable in the esophagus, where the stent graft did not cover the aorta. After elevating the mean blood pressure to > 70mmHg with continuous intravenous noradrenaline infusion, esophageal mucosal blood flow increased significantly in both regions; however, the reaction was different between the two regions. Our newly developed laser Doppler flowmeter could measure real-time esophageal mucosal blood flow changes in various clinical situations during thoracic stent graft implantation in a swine model. Hence, this device can be applied in many medical fields by downsizing it.

X-ray-guided self-expandable metal stent (SEMS) implantation in oesophageal malignancy as an alternative treatment.

&lt;b&gt;&lt;br&gt;Indroduction:&lt;/b&gt; Significant dysphagia, aspiration pneumonia, and impossible oral nutrition in patients with unresectable or recurrent gastroesophageal malignancy or bronchial cancer invading the oesophagus with a tracheoesophageal fistula lead to cachexia. Dehiscence of the esophago-jejunal or gastroesophageal anastomosis may cause severe oesophageal haemorrhage. We believe that X-ray-guided oesophageal stent implantation (SEMS) is an alternative palliative method for microjejunostomy or full parenteral nutrition.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Aim:&lt;/b&gt; The aim of this paper was to assess the safety and efficacy of a novel X-ray-guided oesophageal stent implantation technique.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Materials and methods:&lt;/b&gt; This retrospective analysis included 54 patients (35 men and 19 women) treated for malignant dysphagia, gastroesophageal/gastrointestinal anastomotic fistula or bronchoesophageal fistula in two Surgical Units between 2010 and 2019, using a modified intravascular approach to oesophageal stent implantation.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Results:&lt;/b&gt; The presented modified intravascular method of oesophageal stent implantation was successfully performed in all described patients requiring oral nutrition restoration immediately following oesophageal stent implantation. Two patients with oesophageal anastomotic dehiscence died on postoperative days 7 and 9 due to circulatory and respiratory failure. One patient was reimplanted due to a recurrent fistula. Two patients with ruptured thoracic aneurysm and thoracic stent graft implantation due to oesophageal haemorrhage, who were implanted with an oesophageal stent, died on postoperative days 4 and 14.&lt;/br&gt; &lt;b&gt;&lt;br&gt;Conclusions:&lt;/b&gt; The modified intravascular X-ray-guided SEMS technique may be a palliative treatment for patients with unresectable oesophageal malignancies.&lt;/br&gt.

Re-hybrid thoracic stent graft implantation with total aortic arch debranching in urgent procedure: case report

INTRODUCTION: Implementation of emergency endovascular aortic repair provides an opportunity to treat complicated acute aortic syndromes involving descending aorta. CASE REPORT: A 40-year-old man with a history of aortic coarctation surgical repair as a child and an anastomosis aneurysm repair with a double endovascular stent graft implantation with hemi-arch transposition was urgently admitted with intensifying shortness of breath and hoarseness. A computed tomography study confirmed a blood leak into an aneurysm sac in proximal landing zones of implanted stent grafts (Type I endoleak). Therefore, he qualified for hybrid surgery. First, the ascending aorta brachiocephalic trunk was anastomosed with a 12 mm vascular prosthesis from an upper mini-sternotomy. In the next step, normothermic extracorporeal circulation was necessary to prevent cerebral circulation. Finally, a GORE stent graft (Gore Medical, Flagstaff, AZ, USA) was implanted with a proximal landing zone directly behind the anastomosis site of the vascular prosthesis and ascending aorta. The hospital course was uncomplicated, and the patient was discharged home 5 days after the procedure. CONCLUSIONS: Complicated aortic pathologies requiring emergent interventions can be treated by a hybrid approach utilizing multistep surgical and endovascular techniques achieving optimal results.

Validation and Verification of High-Fidelity Simulations of Thoracic Stent-Graft Implantation

Thoracic Endovascular Aortic Repair (TEVAR) is the preferred treatment option for thoracic aortic pathologies and consists of inserting a self-expandable stent-graft into the pathological region to restore the lumen. Computational models play a significant role in procedural planning and must be reliable. For this reason, in this work, high-fidelity Finite Element (FE) simulations are developed to model thoracic stent-grafts. Experimental crimp/release tests are performed to calibrate stent-grafts material parameters. Stent pre-stress is included in the stent-graft model. A new methodology for replicating device insertion and deployment with explicit FE simulations is proposed. To validate this simulation, the stent-graft is experimentally released into a 3D rigid aortic phantom with physiological anatomy and inspected in a computed tomography (CT) scan at different time points during deployment with an ad-hoc set-up. A verification analysis of the adopted modeling features compared to the literature is performed. With the proposed methodology the error with respect to the CT is on average 0.92 ± 0.64%, while it is higher when literature models are adopted (on average 4.77 ± 1.83%). The presented FE tool is versatile and customizable for different commercial devices and applicable to patient-specific analyses.

Editor's Choice – Four Fenestration Endovascular Aortic Aneurysm Repair Without Stenting of the Coeliac Artery in Selected Cases

Editor's Choice – Four Fenestration Endovascular Aortic Aneurysm Repair Without Stenting of the Coeliac Artery in Selected Cases

Endovascular Treatment of a Life-threatening Blunt Thoracic Aortic Injury in Polytraumatized Patients - A Single Center Experience.

A retrospective analysis of our group of patients, efficacy, safety and the results of endovascular treatment of descending thoracic aorta by using stentgraft implantation in polytraumatized patients. In the period between 6/2006 and 2/2020, in the processing of data, we analysed retrospectively patients with polytrauma diagnosed with thoracic aortic rupture or transection (TAT) and treated with multiple injuries. Clinical characteristics, complications, pathological features, and hospital follow-up data were retrieved from our group. In our group of 28 polytraumatized patients referred to our Trauma Centre with current TAT, all 28 patients with such a thoracic aortic injury were treated by using thoracic stentgraft implantation. In our group of patients, the average Injury Severity Score (ISS) was 22 for women (min 19, max 27) and 26 for men (min 17, max 41), respectively. We reached 100% technical implantation success rate with our patients. In our group, we had 30-day mortality of 10.7% (3 patients) and the in-hospital mortality was 17.8% (5 patients). Surviving patients had calculated ISS score of 25 (min 17, max 41); dead patients had an ISS score of 28 (min 19, max 34) - p≤0.05. Endovascular treatment of TAT, as a minimally invasive and effective procedure with rapid bleeding control, may increase survival chances for severely compromised polytraumatized patients in the context of multiple-organ damage and the need for a major cardio-vascular surgery.

Complicated acute typeB aortic dissection-what does endovascular therapy contribute?

Acute aortic dissection typeB is asevere and life-threatening vascular emergency. Complications such as rupture and/or malperfusion of organs are the main reasons for early mortality. The aim is to provide an overview on important diagnostic radiological findings, conservative as well as endovascular therapeutic options for patients presenting with rupture or malperfusion syndromes. Medical treatment consisting of blood pressure and heart rate control as well las adequate analgesia remains the cornerstone therapy of all typeB aortic dissections. In case of organ malperfusion, various endovascular therapies, e. g., endoluminal fenestration of dissection flap, thoracic stent-graft implantation (TEVAR) or branch vessel stenting, are available. In the case of aortic rupture, TEVAR has become the standard owing to its lower mortality compared to open surgical repair. For the treatment of complicated typeB aortic dissection, a number of endovascular options are available. For optimal treatment, profound knowledge of the disease, of the diagnostic workup, and of the interventional procedures is mandatory.

Oesophageal mucosal blood flow changes after thoracic endovascular stent graft implantation using a novel sensor probe.

Secondary aorto-oesophageal fistula is a rare, lethal complication occurring after thoracic endovascular aneurysmal repair. The cause of secondary aorto-oesophageal fistula is unknown, but a reduction in local oesophageal mucosal blood flow (OMBF) may be a basis for such a devastating sequela. Our study aims to develop a novel blood flow sensor probe to detect changes in OMBF after thoracic stent graft implantation in an experimental swine model. A novel laser Doppler flowmetry sensor probe incorporating an optical fibre sensor within a nasogastric tube was developed using microelectromechanical system technology. OMBF was measured at various levels using this sensor probe, to test its feasibility before and after thoracic endovascular stent graft implantation covering Th4-Th8 vertebral levels in 6 swine. In the middle oesophagus (Th5-Th7), where the aorta was covered with a stent graft, the measured OMBFs were significantly decreased after thoracic endovascular stent graft implantation than those of baseline (8.6 ± 2.7 vs 18.4 ± 7.9 ml/min/100 g, P < 0.0001), followed by a plateau period for at least 2 h after stent grafting (8.7 ± 3.3 ml/min/100 g, P < 0.0001 vs baseline). OMBFs in the upper (Th1-Th3) and lower (Th9-Th11) oesophagus, where the aorta was not covered with a stent graft, were unaffected by thoracic endovascular stent grafting. The novel laser Doppler flowmetry sensor probe was useful to monitor precise changes of OMBF in a swine model, demonstrating a significant reduction in OMBF after thoracic endovascular stent graft implantation.

Number and Location of Abdominal Aorta Entry Tear is Associated with Abdominal Aorta Remodeling After Stent Grafting for Complicated Type B Aortic Dissection

Introduction: Thoracic endovascular aorta repair for complicated type B aortic dissection is a challenging issue in last decade. The remodelling process of aorta false lumen is still unknown and hard to predict, especially in the abdominal aorta part. In this study, we try to find out some impact factors from retrospective analysis in our patient group. Methods: From November 2006 to July 2012, 84 patients received thoracic stent graft implantation +/− cervical bypass due to complicated type B aortic dissection in our institute. 73 of them had regular post-operative contrast computed tomography scan follow up more than 1 year and then were included in our study. Most of the (71 of 73) false lumen in thoracic aorta got total thrombosis or obliterated without any contrast. However, the false lumen of abdominal aorta got total thrombosis or obliterated without any contrast only in 27 of 73 patients (regression group) while the false lumen were still patent in other 46 patients (non-regression group). We measured the number and the location (thoracic aorta, supra-renal aorta, infra-renal aorta, iliacs) of all entry tears in pre-operative computed tomography scan and compare the results between two groups. Results: Pre-operative number of entry tear in abdominal aorta is significantly higher in non-regression group (3.36 ± 2.26 versus 1.22 ± 1.15, P < 0.001). Fewer entry tears are found over supra-renal aorta in regression group. (1.54 ± 1.18 versus 0.56 ± 0.75, P < 0.001) The incidence of distal stent graft induced new entry is much higher in non-regression group (P < 0.05). Conclusion: The number and the location of entry tear are the predictors of abdominal aorta remodelling after TEVAR for complicated type B aortic dissection. If pre-operative number of entry tear in abdominal aorta, especially supra-renal aorta, is fewer, the remodelling of dissected aorta after TEVAR will process better.

Invited Commentary

Invited Commentary

Patients' Radiation Doses During Thoracic Stent-Graft Implantation: The Problem of Long-Lasting Procedures

This article investigates patient radiation doses during implantation of thoracic stent-graft. Aortic stengraft implantation can be disturbed by many factors, which, in turn, lead to prolongation of the procedure time and, as a consequence, increase the radiation dose. Measurements of radiation length (fluoroscopy and exposure), air kerma (AK) in grays, and dose-area product in grays·square centimeters were conducted simultaneously in 100 patients. The patients were analyzed retrospectively, regarding their body mass index (BMI), type of aneurysms, number of stent-graft parts, angulation of aorta, and coverage of the left subclavian artery. Mean total dose-area product value for this kind of treatment was 361 Gy·cm2. This was caused by the fact that total mean AK was high for the cohort analyzed and reached 797 mGy. For 23 patients total AK was between 1 and 2 Gy, and for 3 it exceeded 2 Gy. In the remaining group, the maximal radiation dose was very high and exceeded 3 Gy. The total AK of patients with BMI within the range of 25 to 29.9 kg/m2 and with BMI greater than 30 kg/m2 significantly increased in comparison with the group of patients with BMI between 18 and 24.9 kg/m2 (p=0.00005 and 0.000001, respectively). During the study, a good correlation between AK and fluoroscopy time (r=0.6) and for AK (or dose-area product) and exposure time (r=0.66 or 0.81, respectively) was observed. The main factors contributing to a high radiation dose being acquired by patients during thoracic stent-graft were BMI greater than 25 kg/m2, number of parts of the stent-graft, and angulation of the neck of aneurysm exceeding 60 degrees.

Combined Open and Endovascular Repair for Aortic Arch Pathology

Background and ObjectivesWe describe our experience with combined open and endovascular repair in patients who have aortic arch pathology.Subjects and MethodsThis study is a retrospective analysis of 7 patients who underwent combined open and endovascular repair for aortic arch pathology. Medical records and radiographic information were reviewed.ResultsA total of 7 consecutive patients (5 men, 71.4%) underwent thoracic stent graft implantation. The mean age was 59.9±16.7 years. The indication for endovascular repair was aneurysmal degeneration in 5 patients, and rupture or impending rupture in 2 patients. In all 7 cases, supra-aortic transposition of the great vessels was performed successfully. Stent graft implantation was achieved in all cases. Surgical exposure of the access vessel was necessary in 2 patients. A total of 9 stent grafts were implanted (3 stent grafts in one patient). The Seal thoracic and the Valiant endovascular stent graft were implanted in 6 patients and 1 patient, respectively. There were no post-procedure deaths or neurologic complications. In 2 patients, bleeding and injury of access vessel were noted after the procedure. Postoperative endoleak was noted in 1 patient. One patient died at 10 months after the procedure due to a newly developed ascending aortic dissection. No patients required secondary intervention during the follow-up period. The aortic diameter decreased in 4 patients. In 3 patients, including 1 patient with endoleak, there was no change in aortic diameter.ConclusionOur experience suggests that combined open and endovascular repair for aortic arch pathology is safe and effective, with few complications.

Double-Barrel Technique for Endovascular Exclusion of an Aortic Arch Aneurysm Without Sternotomy

To report the use of commercially available stents and a stent-graft in coaxial orientation to extend the proximal limits of endografting within the aortic arch. A 70-year-old man was found to have an asymptomatic 7-cm saccular aortic arch aneurysm, extending distally from the origin of the left carotid artery and involving the left subclavian artery; there was only 11 mm between the innominate artery orifice and the aneurysm. The patient was deemed to be high risk for open surgical repair due to a history of 2 prior sternotomies and the requirement for hypothermic circulatory arrest. A "double-barrel" stent-graft strategy combining retrograde placement of an innominate stent with thoracic stent-graft implantation into zone 0 was successfully executed. The patient has continued to fare well after 10 months on close follow-up. The "double-barrel" stent technique may extend the limits of thoracic endografting by preserving the aortic arch branches while avoiding the need for sternotomy. Using this technique, proximal fixation can be obtained well into the ascending aorta using commercially available devices.

Endovascular Repair of Thoracic Aortic Aneurysm and Intramural Hematoma in Giant Cell Arteritis

An 80-year-old woman with established giant cell arteritis presented at the authors' institution with a 6.5-cm false aneurysm of the descending thoracic aorta complicated by focal dissection and intramural hematoma after a 1-week history of acute-onset chest pain. The patient underwent uncomplicated endovascular aortic repair with a 32-mm x 15-cm TagExcluder stent-graft. After the procedure, the intramural hematoma resolved and the patient's corticosteroid and immunosuppressive therapy was repeatedly adjusted. However, the giant cell arteritis activity relapsed after 8 months with development of a similar 1.5-cm false aneurysm below the thoracic stent-graft, complicated by focal intramural hematoma. Repeat uncomplicated thoracic stent-graft implantation was performed and CT follow-up displayed resorption of the intramural hematomas with no evidence of endoleak or any new aortic pathology. This report discusses the difficult management of patients with relapsing active aortic giant cell arteritis and the potential role for endovascular thoracic aortic repair.