Treatment of Aortoiliac Occlusive Lesions by Aortic Robotic Surgery: Learning Curve and Midterm Outcome

BACKGROUD

The learning curve and midterm results of aortoiliac occlusive disease (AIOD) revascularization by robot-assisted laparoscopic (RAL) surgery may be known.

METHODS

A prospective single-center study was conducted in the vascular surgery department of Georges Pompidou European Hospital (Paris, France). Patients with AIOD treated by RAL from February 2014 to February 2019 were included. Demographic characteristics, past medical history, Trans-Atlantic Inter-Society Consensus (TASC) lesions classifications, mortality, primary and secondary patency, as well as complication rates were collected. Safety was analyzed by the cumulative sum control chart method with a conversion rate of 10%, operative time by cumulative average-time model, and primary and secondary patency by the Kaplan-Meier method.

RESULTS

Seventy patients were included, 18 (25.7%) with TASC C lesions and 52 (74.3%) with TASC D lesions. Before discharge, 14 (24.3%) patients had surgical complications. Among them, 10 (14.3%) required at least one reintervention. One (1.4%) patient died during the hospitalization. The learning curve in terms of safety (conversion rate) was 13 cases with an operating time of 220 minutes after 35 patients. During follow-up (median 37 months [21; 49]), 63 patients (91.3%) improved their symptoms, 53 (76.8%) became asymptomatic, and 3 graft limb occlusions occurred. The primary patency at 12, 24, 36, and 48 months was 94%, 92%, 92%, and 92%, respectively, while the secondary patency for the same intervals was 100%, 98.1%, 98.1%, and 98.1%, respectively.

CONCLUSIONS

Robotic surgery in AIOD revascularization seems safe and effective; allowing to treat patients with few comorbidities and severe lesions, in a dedicated center experienced in RAL, with excellent patency. Prospective clinical trials should be performed to confirm safety.

Thoracic Endovascular Repair after Total Aortic Arch Replacement with Frozen Elephant Trunk for Type a Aortic Dissection

BACKGROUND

The management of residual aortic dissection after initial type A repair with the Frozen elephant trunk technique remains mostly unexplored. This work aimed to evaluate endovascular second-stage surgery for patients with residual aortic dissection.

METHODS

A retrospective analysis of consecutive patients that underwent Type A aortic repair with Frozen elephant trunk, followed by a second-stage endovascular procedure was done from March 2016 to December 2021. The primary outcome was aortic-related adverse events or mortality, and secondary outcomes were aortic remodeling and perioperative complications. Remodeling was assessed by comparing the difference in ratios for true lumen/total aortic diameters on pre-operative and follow-up scans.

RESULTS

Thirty-four patients underwent second-stage surgery after Type A repair during the study period (7 thoracic endovascular aortic repair extensions, 1 STABLE/PETTICOAT, and 26 STABILISE). Median follow-up was 23 months (range 2-66 months). There were no perioperative deaths or major complications and 1 reoperation for left subclavian re-embolization. At the last follow-up, there was no aortic-related mortality. There were 5 aortic-related adverse events, including another subclavian re-embolization and a preplanned open conversion. Risk factors were connective tissue disorders (P = 0.01) and aortic aneurysms >55 mm (P = 0.03). Distal remodeling reached statistical significance in all segments (P < 0.01) and was greater for patients treated with the STABILISE technique when compared to extended thoracic endovascular aortic repair (P = 0.01).

CONCLUSIONS

Second-stage endovascular management of residual aortic dissection after initial Frozen elephant trunk repair showed excellent perioperative and good midterm outcomes and induced significant remodeling of the entire aorta in most cases, particularly with the STABILISE procedure.

Is carotid web an arterial wall dysplasia? A histological series

INTRODUCTION

Described for 60 years under various names, the carotid web is a suspected cause of cryptogenic stroke, especially in young patients. The web creates an intraluminal protrusion that may contribute to turbulent flow and thrombus embolization into cerebral arteries. Although the carotid web has frequently been related to arterial fibrodysplasia, its natural history and pathological description remain unclear.

PATIENTS

Among all consecutive patients admitted to the stroke unit of Sainte-Anne Hospital and referred to the vascular surgery department from January 2015 to December 2022, we retrospectively identified 9 patients with a carotid web. The surgical specimens of the 9 patients were submitted to systematic pathological analysis.

RESULTS

The patients with a histologically confirmed carotid web were young (median age was 42 years), prominently women (7/9), and presenting with low cardiovascular risk. Eight patients had a stroke proven by a magnetic resonance imaging, and 1 had transient monocular amaurosis. The typical pathological lesion supporting the imaging pattern of the carotid web was a focal eccentric intimal hyperplasia forming a protruding lesion characterized by a population of vascular smooth muscle cells intermingled in an abundant, most often loose extracellular matrix. Pathologically proven thrombus was observed in 4 cases. Importantly atherosclerosis was absent.

CONCLUSION

Histological features in our 9 cases strengthen carotid web characterization as a homogeneous pattern of localized intimal hyperplasia. It is a unique entity consistent with intimal fibroplasia, distinct from medial fibromuscular dysplasia and early atherosclerosis.

Ruptured infective native thoracic aortic aneurysm treated by endovascular repair as a bridge therapy to open repair

We report the case of a 70-year-old woman who presented with a ruptured infective native thoracic aortic aneurysm (INTAA), associated with spondylodiscitis and posterior mediastinitis. She underwent a staged hybrid repair: urgent thoracic endovascular aortic repair was first performed as a bridge therapy in the context of septic shock. Allograft repair using cardiopulmonary bypass was performed five days later. Given the complexity of INTAA, multidisciplinary teamwork was paramount to determine the most appropriate treatment strategy, including procedure planning with multiple operators as well as perioperative care. Therapeutic alternatives are discussed.

Thrombosis of Medium-Sized and Large Arteries During Covid-19 Infection: Results of the COVIVASC Study

BACKGROUND

COVID-19 infection is associated not only with venous thromboses but also with arterial thromboses (COV-ATs) in relation with an endothelial dysfunction, a coagulopathy and rhythm disorders. The incidence, the topography, and the prognosis of COV-ATs remain poorly known. The objective of this study was to report the overall experience of the Greater Paris University Hospitals (Assistance Publique - Hopitaux de Paris, AP-HP) during the first pandemic wave of COVID-19 infection.

METHODS

After approval by the ethics committee, a study using the AP-HP clinical data warehouse was carried out between March and May 2020. Overall, 124,609 patients had a polymerase chain reaction for COVID-19 in our hospitals, of which 25,345 were positive. From 20,710 exploitable stays, patients tested positive for COVID who presented an episode of acute COV-AT (except coronary and intracranial arteries) were selected on the basis of the French medical classification for clinical procedures codes. The data are presented as absolute values with percentages and/or means with standard deviation.

RESULTS

Over the studied period, 60 patients (aged 71±14 years, 42 men) presented a COV-AT at the time of their hospitalization, an incidence of 0.2%. The arterial complication occurred 3±7 days after the COVID infection and was inaugural in 30% of the cases (n = 18). The sites of COV-AT were the lower extremities (n = 35%, 58%), the abdominal aorta (n = 10%, 17%), the thoracic aorta (n = 7%, 12%), the upper limbs (n = 7%, 12%), the cerebral arteries (n = 7%, 12%), the digestive arteries (n = 6%, 10%), the renal arteries (n = 2%, 3%), and the ophthalmic artery (n = 1%, 2%). Multiple COV-ATs were observed in 13 patients (22%). At the time of diagnosis, 20 (33%) patients were in intensive care, including six (10%) patients who were intubated. On computed tomography angiography, COVID lesions were classified as moderate and severe in 25 (42%) and 21 (35%) cases, respectively. Revascularization was attempted in 27 patients (45%), by open surgery in 16 cases, using endovascular techniques in 8 cases and with a hybrid approach in three cases. Six patients (22%) required reinterventions. The duration of hospitalization was 12±9 days. Early mortality (in-hospital or at 30 days) was 30% (n = 18). Nine (15%) patients presented severe nonlethal ischemic complications.

CONCLUSIONS

Arterial involvement is rare during COVID-19 infection. The aorta and the arteries of the limbs are the privileged sites. The morbi-mortality of these patients is high. Future studies will have to determine if the systematization of anticoagulation therapy decreases the incidence and the severity of the condition.

Women Specific Characteristics and 1-Year Outcome Among Patients Hospitalized for Peripheral Artery Disease: A Monocentric Cohort Analysis in a Tertiary Center

Although women have lower age-standardized cardiovascular disease incidence, prevalence, and death-related rates than men, there are also reports indicating that women with cardiovascular disease receive less care, fewer investigations, and have poorer outcomes after a coronary event. The aims of this study were to compare the characteristics of men and women hospitalized for peripheral artery disease (PAD), their cardiovascular and limb outcomes, and their 1-year mortality. The study is a prospective registry collecting data about all consecutive patients hospitalized for PAD within the vascular department of the tertiary center Georges-Pompidou European Hospital (Paris, France). Patients were required to have one of three inclusion criteria: previous revascularization of the lower limb or any lower limb artery occlusion due to an atherosclerotic vascular disease or hemodynamic evidence of PAD. Exclusion criteria were patients with lower extremity arterial occlusion due to another cause. All patients were followed-up for at least 12 months after the initial hospitalization. Among the 235 patients included, there were 61 women (26%), older than men with a median age of 75.6 and 68.3 years, respectively. Main cardiovascular risk factors and comorbidities were similar for men and women except more former or current smokers [145 (83.4%) vs. 33 (54.1%)] and more history of coronary heart disease [42 (24.1%) vs. 7 (11.5%)] in men. Most patients [138 (58.8%)] had critical limb ischemia and 97 (41.3%) had claudication, with no difference for sex. After discharge, 218 patients received an antithrombotic therapy (93.2%), 195 a lipid-lowering drug (83.3%), 185 an angiotensin converting enzyme inhibitor or angiotensin-receptor blocker (78.9%), similarly between sex. At 1-year, overall mortality, major adverse cardiovascular events, major adverse limb events did not differ with 23 (13.2%), 11 (6.3%) and 32 (18.4%) in men, and 8 (13.1%), 3 (4.9%), 15 (24.6%) in women, respectively, despite the difference in age. Overall mortality, cardiovascular outcomes, limb revascularization or amputation did not differ between men and women, 1-year after hospitalization for PAD although the latter were older, less smoker and had less coronary artery disease. Due to the small size of this cohort, larger studies and future research are needed to better understand sex-specific mechanisms in the pathophysiology and natural history of PAD.

Blunt Traumatic Aortic Injury Management, a French TraumaBase Analytic Cohort

OBJECTIVE

Blunt traumatic aortic injury (BTAI) in severe trauma patients is rare but potentially lethal. The aim of this work was to perform a current epidemiological analysis of the clinical and surgical management of these patients in a European country.

METHODS

This was a multicentre, retrospective study using prospectively collected data from the French National Trauma Registry and the National Uniform Hospital Discharge Database from 10 trauma centres in France. The primary endpoint was the prevalence of BTAI. The secondary endpoints focused chronologically on injury characteristics, management, and patient outcomes.

RESULTS

209 patients were included with a mean age of 43 ± 19 years and 168 (80%) were men. The calculated prevalence of BTAI at hospital admission was 1% (162/15 094) (BTAI admissions/all trauma). The time to diagnosis increased with the severity of aortic injury and the clinical severity of the patients (grade 1: 94 [74, 143] minutes to grade 4: 154 [112, 202] minutes, p = .020). This delay seemed to be associated with the intensity of the required resuscitation. Sixty seven patients (32%) received no surgical treatment. Among those treated, 130 (92%) received endovascular treatment, 14 (10%) open surgery (two were combined), and 123 (85%) were treated within the first 24 hours. Overall mortality was 20% and the attributed cause of death was haemorrhagic shock (69%). Mortality was increased according to aortic injury severity, from 6% for grade 1 to 65% for grade 4 (p < .001). Twenty-six (18.3%) patients treated by endovascular aortic repair had complications.

CONCLUSION

BTAI prevalence at hospital admission was low but occurred in severe high velocity trauma patients and in those with a high clinical suspicion of severe haemorrhage. The association of shock with high grade aortic injury and increasing time to diagnosis suggests a need to optimise early resuscitation to minimise the time to treatment. Endovascular treatment has been established as the reference treatment, accounting for more than 90% of interventional treatment options for BTAI.

Carotid plaque vulnerability assessed by combined shear wave elastography and ultrafast doppler compared to histology: the UF-plaque study

Purpose

New biomarkers are needed to assess the vulnerability of carotid plaque to guide carotid surgery decision. Ultrafast Ultrasound Imaging (UUI) provides an estimation of plaque stiffness by Shear Wave Elastography (SWE) and the quantification of wall shear stress (WSS) by ultrafast Doppler. We aimed at evaluating the plaque stiffness and WSS applied on the plaque as potential biomarkers of plaque vulnerability.

Methods

Patients were referred for carotid endarterectomy because of symptomatic or asymptomatic carotid stenosis. Their plaques were evaluated by UUI within 48 hours before surgery. For each plaque, WSS and SWE were obtained on a longitudinal view at the stenosis. After endarterectomy, gross analysis and histology were performed on each removed plaque.

Results

46 plaques with SWE data and 29 with WSS data were analysed. Histological analysis revealed 29 vulnerable and 17 stable plaques. Analysis of the Gray Scale Median by B mode, mean and standard deviation of stiffness by SWE were not helpful in identifying vulnerable plaques. Figure 1 presents the SWE acquisition on one plaque (A) and the distribution of plaque's stiffness average over all plaques showing the 4 ranges of stiffness (B). SWE analysis revealed that the percentage of stiffness range of [3–5] m/s was significantly increased in vulnerable plaques (p=0.048) (Figure 2A). WSS alone showed no significant difference between stable and vulnerable plaques regardless of which segment of the plaque was analysed. A multiparametric score using maximal WSS at the peak of the plaque associated with SWE texture analysis parameters was created by a stepwise analysis, leading to a score with a sensitivity of 80% and a specificity of 78%. The ROC curve of this score found an AUC of 0.85 (Figure 2B).

Conclusions

Multiparameter scoring including plaque stiffness and flow analysis using ultrafast ultrasound imaging allows an effective identification of histologically vulnerable carotid plaques.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Fédération Française de cardiologieSociété Française de Cardiologie Figure 1Figure 2

Carotid Plaque Vulnerability Assessed by Combined Shear Wave Elastography and Ultrafast Doppler Compared to Histology

Ultrafast ultrasound imaging (UUI) provides an estimation of carotid plaque stiffness by shear wave elastography (SWE) and the quantification of wall shear stress (WSS) by ultrafast Doppler. We aimed to evaluate the combined criteria of plaque stiffness and WSS applied on the plaque as potential biomarkers of plaque vulnerability assessed by histology. We included patients for whom carotid endarterectomy had been decided by a multidisciplinary team. UUI was performed within 48 h before surgery, and acquisitions were obtained on a carotid longitudinal view. After endarterectomy, gross examination and histological analysis were performed on each removed plaque. Forty-six plaques with SWE data and 29 with WSS data were analyzed. Histological analysis revealed 29 vulnerable and 17 stable plaques. Gray-scale median analysis by B-mode, mean, and standard deviation of stiffness by SWE did not differ between vulnerable and stable plaques. SWE analysis revealed that the percentage of stiffness range of 3-5 m/s was significantly increased in vulnerable plaques (p = 0.048). WSS alone showed no difference between stable and vulnerable plaques regardless of the segment of the plaque which was analyzed. A multiparametric score using maximal WSS at the peak of the plaque associated with SWE texture analysis parameters was calculated by stepwise regression, leading to a score with a sensitivity of 80% and a specificity of 78%. Area under the receiver operating characteristics curve was 0.85. A multiparameter scoring system including plaque stiffness and flow analysis using UUI allows to effectively identify histologically vulnerable carotid plaques. ClinicalTrials.gov Identifier: NCT03234257.

Dealiasing High-Frame-Rate Color Doppler Using Dual-Wavelength Processing

Doppler ultrasound is the premier modality to analyze blood flow dynamics in clinical practice. With conventional systems, Doppler can either provide a time-resolved quantification of the flow dynamics in sample volumes (spectral Doppler) or an average Doppler velocity/power [color flow imaging (CFI)] in a wide field of view (FOV) but with a limited frame rate. The recent development of ultrafast parallel systems made it possible to evaluate simultaneously color, power, and spectral Doppler in a wide FOV and at high-frame rates but at the expense of signal-to-noise ratio (SNR). However, like conventional Doppler, ultrafast Doppler is subject to aliasing for large velocities and/or large depths. In a recent study, staggered multi-pulse repetition frequency (PRF) sequences were investigated to dealias color-Doppler images. In this work, we exploit the broadband nature of pulse-echo ultrasound and propose a dual-wavelength approach for CFI dealiasing with a constant PRF. We tested the dual-wavelength bandpass processing, in silico, in laminar flow phantom and validated it in vivo in human carotid arteries ( n = 25 ). The in silico results showed that the Nyquist velocity could be extended up to four times the theoretical limit. In vivo, dealiased CFI were highly consistent with unfolded Spectral Doppler ( r²=0.83 , y=1.1x+0.1 , N=25 ) and provided consistent vector flow images. Our results demonstrate that dual-wavelength processing is an efficient method for high-velocity CFI.

Wall Shear Stress Measurement by Ultrafast Vector Flow Imaging for Atherosclerotic Carotid Stenosis

OBJECTIVE

 Carotid plaque vulnerability assessment could guide the decision to perform endarterectomy. Ultrafast ultrasound imaging (UF) can evaluate local flow velocities over an entire 2D image, allowing measurement of the wall shear stress (WSS). We aimed at evaluating the feasibility of WSS measurement in a prospective series of patients with carotid stenosis.

METHODS

 UF acquisitions, performed with a linear probe, had an effective frame rate of 5000 Hz. The flow velocity was imaged over the entire plaque area. WSS was computed with the vector field speed using the formula: with the blood velocity and μ, the blood viscosity. The WSS measurement method was validated using a calibrated phantom. In vivo, WSS was analyzed in 5 areas of the carotid wall: common carotid artery, plaque ascent, plaque peak, plaque descent, internal carotid artery.

RESULTS

 Good correlation was found between in vitro measurement and the theoretical WSS values (R₂ = 0.95; p < 0.001). 33 patients were prospectively evaluated, with a median carotid stenosis degree of 80 % [75-85]. The maximum WSS value over the cardiac cycle follows the shape of the plaque with an increase during the ascent, reaching its maximum value of 3.25 Pa [2.26-4.38] at the peak of the plaque, and a decrease after passing of the peak (0.93 Pa [0.80-1.19]) lower than the WSS values in the non-stenotic areas (1.47 Pa [1.12-1.77] for the common carotid artery).

CONCLUSION

 UF allowed local and direct evaluation of the plaque's WSS, thus better characterizing local hemodynamics to identify areas of vulnerability.

KEY POINTS

  · Ultrafast vector Doppler allows calculation of the wall shear stress (WSS) by measuring velocity vectors over the entire 2D image.. · The setup to measure the WSS has been validated in vitro on a linear flow phantom by comparing measurements to in silico calculations.. · Applying this method to carotid plaque allows us to better describe the hemodynamic constraints that apply along the entire length of the plaque..

Non-invasive recanalization of deep venous thrombosis by high frequency ultrasound in a swine model with follow-up

AIMS

Pulsed cavitational ultrasound therapy (thombotripsy) allows the accurate fractionation of a distant thrombus. We aimed to evaluate the efficacy and safety of non-invasive thrombotripsy using a robotic assisted and high frequency ultrasound approach to recanalize proximal deep venous thrombosis (DVT) in a swine model.

METHODS

Occlusive thrombosis was obtained with a dual jugular and femoral endoveinous approach. The therapeutic device was composed of a 2.25 MHz focused transducer centered by a linear ultrasound probe, and a robotic arm. The feasibility, security, and efficacy (venous channel patency) assessment after thrombotripsy was performed on 13 pigs with acute occluded DVT. To assess the mid-term efficacy of this technique, 8 pigs were followed up for 14 days after thrombotripsy and compared with 8 control pigs. The primary efficacy endpoint was the venous patency. Safety was assessed by the search for local vessel wall injury and pulmonary embolism.

RESULTS

We succeeded in treating all pigs except two with no accessible femoral vein. After median treatment duration of 23 minutes of cavitation, all treated DVT were fully recanalized acutely. At 14 days, in the treated group, six of the eight pigs had a persistent patent vein and two pigs had a venous reocclusion. In the control group all pigs had a persistent venous occlusion. At sacrifice, no local vein nor arterial wall damage were observed as well as no evidence of pulmonary embolism in all pigs.

CONCLUSION

High frequency thrombotripsy seems to be effective and safe for non-invasive venous recanalization of DVT.

Mycobacterium bovis infection of an aortobifemoral bypass graft with Streptococcus intermedius superinfection after intravesical bacillus Calmette-Guérin immunotherapy for bladder cancer

BACKGROUND

The Bacillus Calmette-Guerin (BCG) is a life-attenuated form of Mycobacterium bovis widely used as immunotherapy for localized bladder cancer. Adverse reactions to intravesical BCG instillations are rare.

CASE

We describe a 70-year-old man with a history of an aortobifemoral bypass graft, placement of a synthetic mesh for treatment of a ventral hernia and, most recently, superficial bladder cancer treated with BCG therapy. Ten months after his final intravesical BCG instillation, he complained of fever and asthenia. After 12 months of investigation, he was diagnosed with Mycobacterium bovis infection of his aortobifemoral bypass graft and abdominal mesh, with Streptococcus intermedius superinfection. The bypass graft was excised and replaced with an in situ arterial allograft, the abdominal mesh was removed, and treatment started with amoxicillin, isoniazid, rifampicin and ethambutol. Several additional vascular interventions were needed for allograft degradation, but 12 months after the final procedure, outcome was good.

DISCUSSION AND CONCLUSIONS

Among 35 cases of mycotic aneurysm reported after BCG therapy in the last 10 years, only one involved a vascular prosthesis. Surgical repair of such aneurysms using prosthetic grafts is commonly performed, associated with anti-mycobacterial treatment. Prognosis is poor with mortality of 14% (4/35) and a 26% rate of aneurysm recurrence under treatment (9/35).

Using the OUTBACK Catheter to Overcome Aortic Reentry Issues in Retrograde Open Mesenteric Stenting

BACKGROUND

The purpose of this study was to describe the use of the OUTBACK catheter to overcome aortic reentry issues in acute mesenteric ischemia (AMI) treated by retrograde open mesenteric stenting (ROMS).

TECHNIQUE

The technique is demonstrated in two female patients presenting with late AMI related to flush occlusion of the superior mesenteric artery (SMA). In such cases of thrombotic AMI with clear preoperative evidence of intestinal necrosis, ROMS is the first-line revascularization technique in our intestinal stroke center. Following an open approach of the SMA through laparotomy, the SMA was punctured in a retrograde fashion. Retrograde mesenteric subintimal recanalization was initiated. In case of aortic reentry issue, the OUTBACK Elite (Cordis, Hialeah, Fl) catheter was advanced through the occlusion over a 0.014 guidewire. The aortic reentry was created by puncture of the aortic wall with the OUTBACK needle, positioned in the desired position. After low-profile balloon angioplasty of the reentry site and 0.035 guidewire exchange, ROMS was performed using balloon-expandable covered stent.

CONCLUSIONS

The OUTBACK catheter appears to be a safe and effective tool to overcome aortic reentry issues in ROMS. This technical tip might therefore increase the technical success rate of challenging ROMS and decrease the need for bailout bypass in the septic context of AMI.

Innovative Multiparametric Characterization of Carotid Plaque Vulnerability by Ultrasound

Objective

The degree of stenosis of a carotid plaque is a well-established risk factor for ischemic stroke. Nevertheless, the risk of ipsilateral stroke in asymptomatic carotid stenosis remains low and new imaging markers are needed to better target which patients would benefit most from endarterectomy or intensive medical therapy. Ultrafast ultrasound imaging offers parameters helping at characterizing the carotid plaque by shear wave elastography and Ultrafast Doppler (UFD). We aimed at using these techniques to characterize 3 different ultrasound biomarkers: plaque stiffness heterogeneity, wall shear stress (WSS) and intraplaque micro-flows and to correlate these biomarkers with findings on computed tomography angiography (CTA) and the pathological examination.

Methods

We present the case of a multimodal evaluation of a carotid plaque using ultrasound. Elastography has been coupled to the WSS assessment and the detection of intraplaque micro-flows by UFD. The data have been compared to CTA and to the pathology examination of the tissue after carotid endarterectomy.

Results

Elastography allowed at identifying stiff areas corresponding to calcifications, as well as a soft area corresponding to an intraplaque hemorrhage. The flow evaluation with UFD showed an increase of the WSS along the plaque and identified the presence of a plaque rupture, confirmed by the pathologist.

Conclusion

Ultrafast ultrasound imaging is an innovative, easily accessible technique that provides imaging modalities on top of the conventional B-mode. Ultrafast ultrasound biomarkers such as plaque stiffness heterogeneity, WSS and intraplaque micro-flows could help to define the vulnerability of the carotid plaque in order to stratify patients that could benefit most from endarterectomy or intensive medical therapy.

3041Wall shear stress measurement by ultrafast vector flow imaging for atherosclerotic carotid stenosis

Background

Carotid plaque vulnerability assessment is an important factor in guiding the decision to treat significant carotid stenosis. Ultrafast Ultrasound Imaging (UF) offers the possibility of evaluating local flow velocities over an entire 2D image, allowing access to velocity measurements in contact with the arterial wall and to measure the wall shear stress (WSS).

Purpose

To evaluate the feasibility of WSS measurement in a prospective series of patients with carotid stenosis.

Methods

A 7.5 MHz linear probe of an Aixplorer scanner was used. UF acquisitions had 3 tilted plane waves transmits (−10; 0; 10°) and an effective frame rate of 5000Hz. We evaluated the flow velocity in 5 areas of the carotid wall: common carotid artery (1), plaque ascent (2), plaque peak (3), plaque descent (4), internal carotid artery (5) (Figure). WSS was computed with the vector field speed using the following formula, WSS=μ·δn·v with v the blood velocity, n the normal vector to the vessel wall and μ, the blood viscosity, calculated from the hematocrit value for each patient. WSS measurement method was first validated using a laminar flow phantom and known viscosity. And then, 33 patients were then prospectively evaluated, with a median carotid stenosis degree of 80% [75–85].

Results

Significant correlation was found between in vitro measurement and the theoretical WSS values (R2=0.95; p<0.001).In patients,the maximum WSS value over the cardiac cycle follows the shape of the plaque with an increase during the ascend, reaching its maximum value of 3.57 Pa [2.47–4.45] at the peak of the plaque, and a fall after passing the peak (0.99 Pa [0.8–1.32]) lower than the WSS values in the non-stenotic areas (1.55 Pa [1.13–1.90] for the common carotid artery) (Table).

Table 1 Wall's area Wall shear stress (Pa) Min Max Delta 1. Common carotid artery 0.14 [0.05–0.27] 1.55 [1.13–1.90] 0.73 [0.55–0.96] 2. Plaque's ascent 0.39 [0.24–0.59] 2.63 [1.89–3.28] 1.20 [0.89–1.79] 3. Plaque's peak 0.60 [0.32–0.89] 3.57 [2.47–4.45] 1.78 [1.44–2.46] 4. Plaque's descent 0.16 [0.13–0.22] 0.99 [0.80–1.32] 0.52 [0.34–0.73] 5. Internal carotid artery 0.17 [0.13–0.35] 1.37 [1.04–1.75] 0.72 [0.50–0.87] Results are median [25th–75th percentile].

Figure 1

Conclusion

UF provide reliable WSS values. High WSS was present at the peak of the plaque, whereas lowest WSS values were found at the post-stenotic zone. WSS evaluation may help to better characterize the carotid plaque vulnerability.

Crossed pulmonary arteries as additional cause of dysphagia in association with right aortic arch and Kommerell diverticulum

We describe an uncommon association of crossed pulmonary arteries and a right aortic arch with a Kommerell diverticulum and a left ligamentum arteriosum, resulting in disabling dysphagia in a 33-year-old woman. First, endovascular exclusion of the Kommerell diverticulum was performed using a thoracic stent graft, associated with left subclavian-carotid transposition. Second, open aneurysmorrhaphy and division of the left ligamentum arteriosum allowed a proper release of the oesophageal compression. Dysphagia completely disappeared in the postoperative course. Control computed tomography angiography at 6-month follow-up showed a satisfactory hybrid repair. A complete understanding of the combined effects of these two anatomical variations on oesophageal compression led to a suitable surgical management.

Postmortem Retrieval of Arterial Allografts: Preliminary Results

BACKGROUND

Cryopreserved arterial allografts are vascular substitutes used for arterial reconstructions in a septic field. Their use remains however limited by the shortage of donors. One of the possibilities to address this lack of grafts is to multiply the sources of retrieval. The objective of this preliminary study was the evaluation of the early clinical results and the microbiological safety of arterial grafts retrieved after death.

METHODS

In addition to the standard conditions of arterial sampling, the criteria of inclusion for postmortem retrieval comprised the refrigeration of the body of the donor within 4 hr following the death, a 24-hr time limit from the death, and the availability of an adapted place for retrieval (surgical unit or death chamber respecting the required aseptic conditions). We only retrieved the femoral axes (FAs) and the aortoiliac bifurcation. The conditions of retrieval, transportation, preparation, and conservation were identical to those of cryopreserved arterial allografts harvested during standard multiple organs retrieval. We evaluated the bacteriological risk of contamination and the patency of the grafts in the short and medium term.

RESULTS

In 2015 and 2016, 6 donors were included. Eleven FAs and 2 aortic bifurcations were harvested. The bacteriological samples done on arrival in bank and after thawing were negative in the 6 donors, but one of the 6 donors presented a bacterial contamination of other removed tissues, and the arterial grafts obtained from this donor were destroyed as a precaution (3 grafts). The quality of the grafts evaluated by the surgeon during harvesting was good in all the cases. The indications of allografts were arterial reconstruction in a septic field (n = 8) and aorto-hepatic bypass during hepatic transplantation (n = 1). One graft was unhopefully thawed without being used. At the end of the follow-up, 8 out of 9 grafts were patent. Two ruptures occurred in a context of locally persistent sepsis (crural abscess due to Salmonella typhi and persistent groin wound disunion with a polymicrobial flora). One allograft thrombosis was observed (aorto-hepatic bypass for transplantation). These complications were unrelated to the mode of graft harvesting. No aneurysmal evolution was observed.

CONCLUSIONS

The preliminary results of this protocol are encouraging because the immediate quality of the grafts was good with a risk of microbiological contamination identical with that of the usual harvesting mode. This mode of harvesting looks promising to reduce the shortage in arterial allografts and could be extended to harvest thoracic aortic allografts. However, results at a larger scale are necessary to confirm these data.

Endothelial autophagic flux hampers atherosclerotic lesion development

Blood flowing in arteries generates shear forces at the surface of the vascular endothelium that control its anti-atherogenic properties. However, due to the architecture of the vascular tree, these shear forces are heterogeneous and atherosclerotic plaques develop preferentially in areas where shear is low or disturbed. Here we review our recent study showing that elevated shear forces stimulate endothelial autophagic flux and that inactivating the endothelial macroautophagy/autophagy pathway promotes a proinflammatory, prosenescent and proapoptotic cell phenotype despite the presence of atheroprotective shear forces. Specific deficiency in endothelial autophagy in a murine model of atherosclerosis stimulates the development of atherosclerotic lesions exclusively in areas of the vasculature that are normally resistant to atherosclerosis. Our findings demonstrate that adequate endothelial autophagic flux limits atherosclerotic plaque formation by preventing endothelial apoptosis, senescence and inflammation.

Abstract 590: Autophagy is Required for Endothelial Atheroprotective Signaling Under Physiological Flow

Objective: Preferential development of atherosclerotic lesions in areas of low shear stress is associated with increased endothelial inflammation, apoptosis and senescence. On the contrary, high shear stress areas are protected from plaque development, but the mechanisms remain elusive. Autophagy is a protective mechanism allowing recycling of defective organelles and proteins to maintain cellular homeostasis. Our aim was to understand the role of autophagy in athero-protective effects of high shear stress.

Approach and Results: We used the parallel plate chamber system in vitro to generate different shear stress conditions on endothelial cell deficient or not in autophagy (shRNA Atg5 vs. control) and examined autophagic flux in cells transfected with RFP-GFP-LC3 plasmid. Endothelial autophagy was silenced in Atg5 flox/flox ; VE-cadherin-cre mice. We first demonstrated in human and murine arteries and in cultured endothelial cells that atheroprotective shear stress activates endothelial autophagic flux. On the opposite, endothelial cells exposed to atheroprone low shear stress displayed inefficient autophagy, associated with activation of mTOR, inhibition of AMPKα pathways and blockade of the autophagic flux. Interestingly, plaque burden augmented specifically in areas usually atheroresistant in ApoE -/- hypercholesterolemic mice deficiency in endothelial autophagy. Both in cultured endothelial cells and in transgenic mice, deficiency in endothelial autophagy was associated with a defect in endothelial alignment with flow direction, a hallmark of endothelial cell health. Deficiency in endothelial autophagy increased endothelial senescence and TNFα-induced inflammation under high shear stress conditions. These effects were associated with impaired KLF2 activation. In transgenic mice, endothelial senescence and apoptosis was augmented in high shear stress areas of the descending thoracic aorta when compared to control littermate mice.

Conclusions: Altogether, these results show that adequate endothelial autophagic flux under high shear stress limits atherosclerotic plaque formation by preventing inflammation, senescence and apoptosis.

Management of Vascular Trauma during the Paris Terrorist Attack of November 13, 2015

BACKGROUND

On November 13, 2015, Paris and Saint-Denis were the targets of terrorist attacks. The Public Hospitals of Paris Organization and the Percy Armed Forces Instruction Hospitals were mobilized to face the mass casualty situation. The objective of this study is to analyze the management of the victims presenting with a nonthoracic vascular trauma (NTVT).

METHODS

All the data relating to the victims of NTVT who required a specific vascular open or endovascular treatment were analyzed retrospectively. A 6-month follow-up was obtained for all the patients.

RESULTS

Among the 351 wounded, 20 (5.7%) patients had an NTVT and were dispatched in 8 hospitals (11 men of average age 32). NTVTs were gunshots in 17 cases (85%) or due to a handmade bomb in 3 cases (15%). Twelve patients (60%) received cardiopulmonary resuscitation during prehospital care. NTVT affected the limbs (14 cases, 70%) and the abdomen or the small pelvis (6 cases, 30%). All the patients were operated in emergency. Arterial lesions were treated with greater saphenous vein bypasses, by ligation, and/or embolization. Eleven venous lesions were treated by direct repair or ligation. Associated lesions requiring a specific treatment were present in 19 patients (95%) and were primarily osseous, nervous, and abdomino-pelvic. Severe postoperative complications were observed in 9 patients (45%). Fourteen patients (70%) required blood transfusion (6.4 U of packed red blood cells on average, range 0-48). There were no deaths or amputation and all vascular reconstructions were patent at 6 months.

CONCLUSIONS

The effectiveness of the prehospital emergency services and a multisite and multidisciplinary management made it possible to obtain satisfactory results for NTVT casualties. All the departments of vascular surgery must be prepared to receive many wounded victims in the event of terrorist attacks.

Phlegmasia Cerulea Dolens as an Unusual Presentation of Ruptured Abdominal Aortic Aneurysm into the Inferior Vena Cava

The aim of this case study is to report a case of unusual manifestation of ruptured abdominal aortic aneurysm (AAA) involving an aortocaval fistula (ACF) as phlegmasia cerulea dolens (PCD). A 58-year-old male presented with acute signs of PCD of the right lower limb, confirmed on duplex ultrasonography. Computed tomography angiography revealed a 65-mm ruptured AAA with a large ACF. Successful emergent surgical repair was performed, using implantation of an aortobi-iliac graft with primary closure of the fistula and associated venous thrombectomy. PCD revealing a ruptured AAA with ACF is rare. Knowledge of this original entity might be the most important factor on the outcome.

Technical Aspects of Open Repair for Degenerative Aneurysmal Evolution Despite Early Thoracic Endovascular Repair of Type B Aortic Dissection

BACKGROUND

Closure of the proximal tear by thoracic endovascular aortic repair (TEVAR) at the acute phase appears to be a safe effective treatment to prevent aneurysmal degeneration type B dissection. However, it appears to be inefficient in up to a third of the patient. We report the technical aspects of our experience with patients undergoing secondary open repair after TEVAR for dissecting thoracoabdominal aneurysm despite early closure proximal tear by TEVAR.

METHODS

During a period of 5 years, 96 patients presenting acute type B aortic dissections were treated by TEVAR and followed-up in our institution. Among them, 5 patients experienced an evolution to a dissecting thoracoabdominal aortic aneurysm. Their demographic data and initial medical conditions, delay to reintervention, operative technical details, perioperative and mid-term outcomes were collected and analyzed.

RESULTS

All 5 patients (4 male, mean age 58 ± 9) were operated under peripheral normothermic bypass without deep circulatory arrest using the thoracic stent graft as an elephant trunk for completion of the proximal anastomosis. In cases of patency, the false lumen was reapproximated in the anastomosis, 6 visceral arteries were revascularized selectively. One patient died at day 1 of perioperative ventricular fibrillation due to an acute myocardial infarction. The 4 others are alive without complication after a median of 30 months, range (13-22).

CONCLUSIONS

In our experience, TEVAR was not only efficient at the acute phase to deal with complications, but in cases of subsequent aneurysmal evolution, it made open repair even easier by avoiding very proximal cross-clamping/anastomosis and circulatory arrest.