Native Aorta Research Articles

Aortic hemodynamics assessment prior and after valve sparing reconstruction: A patient-specific 4D flow-based FSI model

IntroductionValve-sparing root replacement (VSRR) of the ascending aorta is a life-saving procedure for the treatment of aortic aneurysms, but patients remain at risk for post-operative events involving the downstream native aorta, the mechanism for which is uncertain. It is possible that proximal graft replacement of the ascending aorta induces hemodynamics alterations in the descending aorta, which could trigger adverse events. Herein, we present a fluid-structure interaction (FSI) protocol, based on patient-specific geometry and boundary conditions, to assess impact of proximal aortic grafts on downstream aortic hemodynamics and distensibility. MethodsCardiac magnetic resonance (CMR), including MRA, cine-CMR and 4D flow sequences, was performed prior and after VSRR on one subject. Central blood pressure was non-invasively acquired at the time of the CMR: data were used to reconstruct the pre- and post-VSRR model and derive patient-specific boundary conditions for the FSI and a computational fluid dynamic (CFD) analysis with the same settings. Results were validated comparing the predicted velocity field against 4D flow dataset, over four landmarks along the aorta, and the predicted distensibility against the cine-CMR derived value. ResultsInstantaneous velocity magnitudes extracted from 4D flow and FSI were similar (p > 0.05), while CFD-predicted velocity was significantly higher (p < 0.001), especially in the descending aorta of the pre-VSRR model (vmax was 73 cm/s, 76 cm/s and 99 cm/s, respectively). As measured in cine-CMR, FSI predicted an increase in descending aorta distensibility after grafting (i.e., 4.02 to 5.79 10−3 mmHg−1). In the descending aorta, the post-VSRR model showed increased velocity, aortic distensibility, stress and strain and wall shear stress. ConclusionsOur Results indicate that i) the distensibility of the wall cannot be neglected, and hence the FSI method is necessary to obtain reliable results; ii) graft implantation induces alterations in the hemodynamics and biomechanics along the thoracic aorta, that may trigger adverse vessel remodeling.

Aortic remodeling and competitive flow after surgical treatment of aortic dissection

Aortic remodeling after dissection is poorly understood and remains a focus of current research. In the present report, we have described the cases of two patients with acute lower extremity ischemia related to malperfusion from aortic dissection treated with extra-anatomic axillobifemoral bypass. During long-term follow-up, aortic remodeling led to reinstitution of flow through the native aorta. This resulted in competitive flow, leading to complete thrombosis of the extra-anatomic conduits. These cases highlight the occurrence of spontaneous aortic recanalization and subsequent competitive flow, two vascular phenomena that are not well understood but can significantly affect patient outcomes.

Differences in procedural metrics and clinical outcomes among patients treated by fenestrated-branched endovascular repair of thoracoabdominal aortic aneurysms using infrarenal aortic versus iliac sealing zones

ObjectiveThe purpose of the present study was to assess the outcomes of fenestrated-branched endovascular aortic repair (FB-EVAR) using infrarenal aortic vs iliac sealing zones. MethodsWe reviewed the clinical data of 430 consecutive patients enrolled in a prospective nonrandomized study to evaluate FB-EVAR from 2013 to 2020. The outcomes were analyzed for patients with extent I to IV thoracoabdominal aortic aneurysms who had undergone FB-EVAR with distal implantation in the native infrarenal aorta. The minimum anatomic criteria for the use of infrarenal aortic seal was a >3-cm length of parallel aorta with a diameter of 18 to 32 mm without excessive thrombus or calcification. A control group matched for the extent of aortic disease with an iliac artery seal was used to compare the following endpoints: 30-day mortality, major adverse events, freedom from type Ib endoleak (TIbE), freedom from secondary interventions, and changes in the infrarenal aortic diameter. ResultsA total of 110 patients (55 men; mean age, 73 ± 8 years) were included in the present study, 55 with an infrarenal aortic distal seal and 55 with the iliac arteries as the sealing zone. Both groups had similar clinical characteristics and aneurysm extent and diameter, except for a greater number of men and higher serum creatinine in the iliac seal group. Technical success was obtained in 106 patients (96%) and was greater for the iliac sealing zone group (100% vs 93%; P = .04). The use of the infrarenal aortic sealing zone was associated with shorter endovascular (148 ± 56 minutes vs 191 ± 61 minutes; P < .001) and fluoroscopy (76 ± 28 minutes vs 96 ± 32 minutes; P < .001) times and lower radiation exposure (cumulative air kerma, 1.4 ± 1.4 Gy vs 2.1 ± 2.0 Gy; P = .02; dose area product, 147 ± 75 Gy ∙ cm2 vs 208 ± 102 Gy ∙ cm2; P = .006). One patient had died (1%) within 30 days. No differences were found in the major adverse events among the patients treated with infrarenal aortic vs iliac sealing zones (22% vs 18%; P = .63), including any spinal cord injury (13% vs 9%; P = .54) and grade 3 spinal cord injury (7% vs 7%; P = 1.0). The mean clinical follow-up was 24 ± 18 months. TIbE occurred in one patient in each group (P = 1.0). The 3-year freedom from TIbE and freedom from secondary intervention rate was 98% ± 2% and 67% ± 8% for the infrarenal aortic seal group and 97% ± 3% and 67% ± 8% for the iliac seal group, respectively (P = NS). Among the patients treated with infrarenal aortic sealing zones, the mean enlargement of the infrarenal aortic diameter was 5 ± 3.2 mm at 3 years. No late TIbE due to disease progression had developed in the infrarenal aorta. ConclusionsInfrarenal aortic and iliac artery seal zones are safe and effective during FB-EVAR, provided the patients have suitable segments. The use of the infrarenal aortic sealing zone had modest procedural advantages such as shorter endovascular and fluoroscopy times and lower radiation exposure. No differences were found in the clinical outcomes or development of TIbEs.

Effect of luminal surface structure of decellularized aorta on thrombus formation and cell behavior.

Due to an increasing number of cardiovascular diseases, artificial heart valves and blood vessels have been developed. Although cardiovascular applications using decellularized tissue have been studied, the mechanisms of their functionality remain unknown. To determine the important factors for preparing decellularized cardiovascular prostheses that show good in vivo performance, the effects of the luminal surface structure of the decellularized aorta on thrombus formation and cell behavior were investigated. Various luminal surface structures of a decellularized aorta were prepared by heating, drying, and peeling. The luminal surface structure and collagen denaturation were evaluated by immunohistological staining, collagen hybridizing peptide (CHP) staining, and scanning electron microscopy (SEM) analysis. To evaluate the effects of luminal surface structure of decellularized aorta on thrombus formation and cell behavior, blood clotting tests and recellularization of endothelial cells and smooth muscle cells were performed. The results of the blood clotting test showed that the closer the luminal surface structure is to the native aorta, the higher the anti-coagulant property. The results of the cell seeding test suggest that vascular cells recognize the luminal surface structure and regulate adhesion, proliferation, and functional expression accordingly. These results provide important factors for preparing decellularized cardiovascular prostheses and will lead to future developments in decellularized cardiovascular applications.

Short and Mid Term Outcomes of Cryopreserved Abdominal Aortic Allografts Used as a Substitute for Infected Prosthetic Grafts in 200 Patients

To investigate the use of cryopreserved arterial allografts (CAA) as a substitute for infected infrarenal aortic prostheses, and its outcomes. A single centre retrospective study of consecutive patients receiving an abdominal aortic CAA after removal of an infected graft was conducted between January 1997 and December 2013. The primary outcome was the rate of allograft related revision surgery. Secondary outcomes were the 30 day mortality rate, survival, primary patency, limb salvage, and infection recurrence. Allograft ruptures secondary to infection and risk factors for allograft failure were also investigated. Two hundred patients (mean age 64.2 ± 9.4 years) were included. In 56 (28%) cases, infection was related to an enteric fistula. The mean follow up duration was 4.1 years. The 30 day mortality rate was 11%. Early revision surgery was needed in 59 patients (29.5%). Among them, 15 (7.5%) were allograft related and led to the death of three patients (1.5%), corresponding to a 7.5% 30 day allograft related revision surgery rate. During the first six months, 17 (8.5%) patients experienced 21 events with complete or partial rupture (pseudo-aneurysm) of the allograft responsible for five (2.5%) deaths, corresponding to a re-infection rate of 8.5%. The multivariable analysis showed that diabetes and pseudo-aneurysm of the native aorta on presentation were predictive factors for short term allograft rupture. After six months, 25 (12.5%) patients experienced long term allograft complications (rupture, n= 2, 1%; pseudo-aneurysm, n= 6, 3%; aneurysm, n= 2, 1%; thrombosis, n= 11, 5.5%; stenosis, n= 4, 2%;) requiring revision surgery resulting in one death. The five year rates of survival, allograft related revision surgery, limb salvage, primary patency, and infection recurrence were 56%, 30%, 89%, 80%, and 12%, respectively. CAAs provide acceptable results to treat aortic graft infection with few early graft related fatal complications. Long term allograft related complications are quite common but are associated with low mortality and amputation rates.

Electrospinning of small diameter vascular grafts with preferential fiber directions and comparison of their mechanical behavior with native rat aortas

Conventional electrospun small diameter vascular grafts have a random fiber orientation. In order to achieve mechanical characteristics similar to a native blood vessel, a controllable fiber orientation is of interest. In this study the electrospinning jet was directly controlled by means of an auxiliary, changeable electrostatic field, so that the fibers could be deposited in adjustable orientations. Prostheses with circumferentially, axially, fenestrated and randomly aligned fibers were electrospun on Ø2mm mandrels out of a thermoplastic polyurethane (PUR) and a polylactid acid (PLLA). The impact of the materials and the various preferential fiber orientations on the resulting biomechanics was investigated and compared with that of the native rat aorta in quasistatic and dynamic hoop tensile tests. The test protocol included 3000 dynamic loading cycles in the physiological blood pressure range and ended with a quasistatic tensile test. Any orientation of the fibers in a particular direction resulted in a significant reduction in scaffold porosity for both materials. The standard randomly oriented PUR grafts showed the highest compliance of 29.7 ± 5.5 [%/100 mmHg] and were thus closest to the compliance of the rat aortas, which was 37.2 ± 6.5 [%/100 mmHg]. The maximum tensile force was increased at least 6 times compared to randomly spun grafts by orienting the fibers in the circumferential direction. During the 3000 loading cycles, creeping of the native rat aorta was below 1% whereas the electrospun grafts showed creeping up to 2.4 ± 1.2%. Although the preferred fiber orientations were only partially visible in the scanning electron micrographs, the mechanical effects were evident. The investigations suggest a multi-layer wall structure of the vascular prosthesis, since none of the preferred fiber directions and the materials used could imitate the typical j-shaped mechanical characteristics of the rat aorta.

Native and prosthetic graft infections of the thoracic aorta: surgical management.

Infection of the native aorta or after previous open or endovascular repair of the thoracic aorta is associated with high risks for morbidity and mortality. We analysed the outcome after surgical management of a native mycotic aneurysm or of prosthetic graft infection of the descending aorta. From June 2000 to May 2019, a total of 39 patients underwent surgery in our centre for infection of the native descending aorta (n = 19 [49%], group A) or a prosthetic descending aorta [n = 20 (51%), group B]. In the 20 patients in group B, a total of 8 patients had prior open aortic repair with a prosthesis and 12 patients had a previous endovascular graft repair. The cohort patients had a mean age of 57 ± 14; 62% were men (n = 24). The most common symptoms at the time of presentation included fever, thoracic or abdominal pain and active bleeding. Emergency surgery was performed in 11 patients (28%); 3 patients had emergency endovascular stent grafts implanted during thoracic endovascular aortic repair for aortic rupture before further open repair. The 30-day mortality was 42% in group A and 35% in group B. The 90-day mortality was 47% in group A and 45% in group B. Pathogens could be identified in approximately half of the patients (46%). The most commonly identified pathogens were Staphylococcus aureus in 6 patients (15%) and Staphylococcus epidermidis in 4 patients (10%). Survival of the entire group (including patients with both native and prosthetic graft infections) was 44 ± 8%, 39 ± 8% and 39 ± 8% at 1, 2 and 3 years after surgery. The percentage of patients who survived the initial perioperative period was 81 ± 9%, 71 ± 9% and 71 ± 10% at 1, 2 and 3 years after surgery. Patients with infection of the descending aorta, either native or prosthetic, are associated with both high morbidity and mortality. However, patients who survive the initial perioperative period have an acceptable long-term prognosis. In emergency situations, thoracic endovascular aortic repair may help to stabilize patients and serve as bridge to open repair.

Treatment of infectious aortic disease with bovine pericardial tube grafts

Our aim was to evaluate the mid-term outcomes of bovine pericardial tube graft repair for infectious aortic disease in any aortic segment. Between May 2015 and July 2020, 45 patients were treated for infectious aortic disease of the native (n = 9) aorta or after (endo-)graft (n = 36) implantation with bovine pericardial tube grafts. Clinical, infectious details, outcomes and follow-up data were evaluated. All aortic segments underwent pericardial tube graft or bifurcational replacement: the aortic root (n = 12, 27%), ascending aorta (n = 18, 40%), aortic arch (n = 7, 16%), descending aorta (n = 5, 11%), thoraco-abdominal aorta (n = 6, 13%) and abdominal aorta (n = 18, 40%) including the iliac arteries (n = 14, 31%). Organ fistulation (n = 15, 33%) was the most common underlying pathology. Seven patients (16%) expired in-hospital secondary to ongoing sepsis (n = 5, 11%), respiratory failure (n = 1, 2%) and unknown cause (n = 1, 2%). A fungal infection was predictive for in-hospital mortality (P = 0.026, odds ratio: 19.470). After a median follow-up of 11 [first quartile: 2, third quartile 26] months, 9 additional patients (20%) expired and 1 patient developed a postoperative spondylodiscitis at the level of the aortic tube graft. Hence, freedom from proven aortic graft re-infection was 98%. Orthotopic aortic reconstruction using bovine pericardial tube grafts to treat infectious aortic disease is possible in any aortic segment. Organ fistulation is a frequently observed disease mechanism requiring concomitant treatment. Granted, the early attrition rate is substantial, but after the initial period, both survival and freedom from re-infection appear encouraging.

A Flexible 3D Printed Template to Assist with Physician Modified Endografts for FEVAR

Fenestrated endovascular aneurysm repair (FEVAR) for juxtarenal AAAs is limited by cost and the availability of custom made endografts, in addition to technical complexity. Rigid 3D printed anatomical models of the visceral aorta have been used to supplement fenestration placement and as an alternative to conventional centreline based planning; however, these do not simulate the geometric interaction between wires, delivery system, endograft, and aortic tissue. We present a novel translucent, flexible 3D printed template which simulates aortic conformation. Flexible templates better approximate the straightening of native aorta when endografts are deployed and may assist fenestration planning to reduce the risk of splanchnic vessel misalignment. The visceral segment of a juxtarenal AAA was modelled from a computed tomography aortogram, with the splanchnic vessels cropped at their origin to allow fenestrations to be marked (Fig. 1). A Projet 3500 3D printer (3D Systems Corporation, Rock Hill, USA; cost €70 000) was used to print the flexible template. The 3D printed templates are sterilised using ethylene oxide or autoclave techniques. Lunderquist wire cannulation was performed with deployment of an off the shelf Endurant endograft (Medtronic Inc., Minnesota, USA). Splanchnic branch ostia were marked with a sterile pen (Fig. 2). The material was translucent to avoid positioning the fenestrations over struts.Figure 2Fenestrations are planned by marking through the template with a sterile marking pen.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The template was 3D printed in flexible resin (Visijet CE-NT, 3D Systems) on its first attempt over 24 h, costing €95 in materials. This presents a significant time advantage over commercial fenestrated endografts, which require a minimum of one month lead time. In addition, 3D printed template assisted physician modified stent grafts result in substantial cost savings when compared with commercial alternatives. Flexible models may also assist with validation of commercial FEVAR graft construction. 3D printed templates to assist with the back table fenestration of standard commercial endografts are a promising frontier for FEVAR. We report the first instance of a flexible template which mitigates some limitations surrounding templates 3D printed with rigid materials. None.

Development of decellularized aortic scaffold for regenerative medicine using Sapindus mukorossi fruit pericarp extract

The aim of this study is to develop a novel decellularization method using aqueous extract of soap nut pericarp (SPE) and its evaluation using hematoxylin–eosin staining, scanning electron microscopy, diamidino-2-phenylindol (DAPI) staining, mechanical testing, sodium dodecyl sulfate polyacrylamide gel electrophoresis and DNA quantification. The presently available decellularization agent raises some concerns due to the potential for presence of residual cytotoxic agents in the extracellular matrix. Histological analysis of hematoxylin and eosin and masson’s trichrome stained processed aortic samples shows complete decellularization with preservation of extracellular matrix microarchitecture at 120 h. Further, staining of tissue samples with DAPI demonstrates complete removal of DNA fragments. Quantitative evaluation of DNA in the decellularized aorta tissues demonstrated a significant (P < 0.01) decrease in DNA content as compared to native tissues. Collagen quantification assay indicate no significant (P> 0.05) difference in its content between native and decellularized caprine aorta. Tensile strength of the decellularized scaffolds decreased non-significantly (P > 0.05) when compared to native tissues. There was no significant (P > 0.05) difference in young’s modulus of elasticity, stiffness and stretch ratio between native aortic tissues and decellularized aortic scaffolds. Histological and scanning electron microscopic examination of in vitro cultured scaffold demonstrated the cell viability and proliferation of primary chicken embryo fibroblasts. SPE treatment is thus capable of producing cytocompatible decellularized caprine aorta scaffold with preservation of extracellular matrix architecture for vascular tissue engineering and could be applied widely as one of the decellularization agent.

Short-term and Mid-term Outcomes after Use of the Native Infrarenal Aorta as Distal Landing Zone for Fenestrated-Branched Endovascular Aortic Repair

This study aimed to examine outcomes after use of the native infrarenal aorta as distal landing zone for fenestrated-branched endovascular aortic repair (F-BEVAR) of pararenal-thoracoabdominal aortic aneurysms (PRAA-TAAA). All F-BEVAR procedures for treatment of PRAA-TAAA (2011-2019) at 2 aortic centers were examined. The outcomes of interest were as follows: i) technical success, ii) perioperative morbidity, iii) preservation of lumbar arteries and the inferior mesenteric artery, iv) type IB endoleaks, v) reinterventions, vi) survival, vii) aneurysm sac behavior, and viii) infrarenal aortic changes. Twenty consecutive patients with distal landing in the native infrarenal aorta were included (median age 71years; 25% men). The median number of visible lumbar arteries at baseline was 7, and a patent inferior mesenteric artery (IMA) before the operation was present in 19 (95%) of the cases. There were no deaths within 30days. One patient (5%), operated on with a 4-BEVAR for a type 2 TAAA, experienced spinal cord ischemia (permanent paraplegia). The median decrease in the number of visible lumbar arteries at the first postoperative scan was 3 from the baseline value, whereas a patent IMA was preserved in 12 out of 19 patients. Only in one case (5%), a type IB endoleak was noted for an overall technical success rate of 95%, which required a standard EVAR 20months after the initial operation. The median follow-up duration for the study cohort was 491days; all patients were alive at the longest available individual follow-up, and no instances of new-onset type IB endoleaks were observed. Another 3 late reinterventions (in addition to the one mentioned previously) were performed during midterm follow-up, all because of target vessel instability. In patients with ≥12months of follow-up after the index procedure (n=12, 60% of the entire cohort), no instances of aneurysm sac increase >5mm were noted; the median largest aortic diameter was 51mm with a median difference from baseline of -6mm. The median distal landing zone diameter increase was 4mm from baseline but never beyond the nominal stent-graft diameter, whereas the median aortic bifurcation diameter differed 1mm from baseline. This preliminary experience shows that the use of the native infrarenal aorta as a distal landing zone for F-BEVAR is safe in the short term and midterm in patients with suitable anatomy, allowing the sparing of collateral vessels. Longer follow-up is warranted to assess durability.

Increased Aortic Sac Regression and Decreased Infrarenal Aortic Neck Dilation After Fenestrated Endovascular Aneurysm Repair Compared With Standard Endovascular Aneurysm Repair

Aortic neck dilation (AND) can occur in nearly 25% of patients after EVAR, resulting in loss of proximal seal and aortic rupture. Fenestrated endovascular aneurysm repair (FEVAR) affords increased treatment options for patients with shorter infrarenal aortic necks; however, AND has not been well characterized in these patients. This study sought to compare AND in patients undergoing FEVAR vs standard endovascular aneurysm repair (EVAR). Retrospective review was conducted of prospectively collected data of 20 consecutive FEVAR patients (Cook Zenith fenestrated; Cook Medical, Bloomington, Ind) and 20 EVAR patients (Cook Zenith). Demographic and anatomic characteristics, procedural details, and clinical outcome were analyzed. Preoperative, 1-month postoperative, and longest follow-up computed tomography scans were analyzed using a dedicated three-dimensional workstation. Abdominal aortic aneurysm (AAA) neck diameter was measured in 5-mm increments from the lowest renal artery. Standard statistical analysis was performed. Demographic characteristics did not differ significantly between the two cohorts. The FEVAR group had larger mean aortic diameter at the lowest renal artery, shorter infrarenal aortic neck length, increased prevalence of nonparallel neck shape, and longer AAA length (Table). On follow-up imaging, the suprarenal aortic segment dilated significantly more at all suprarenal locations in the FEVAR cohort, whereas the infrarenal aortic neck segment dilated significantly less compared with the EVAR group (Table). The FEVAR group demonstrated significantly greater sac regression vs the EVAR group. Positive aortic remodeling, as evidenced by increased distance from the celiac axis to the most cephalad margin of the AAA, occurred to a more significant degree in the FEVAR cohort. Device migration, endoleak occurrence, and need for reintervention were similar in both groups. Compared with EVAR, patients undergoing FEVAR had greater extent of suprarenal AND, consistent with a more diseased native proximal aorta. However, the infrarenal neck, which is shorter and also more diseased in FEVAR patients, appears more stable in the postoperative period compared with EVAR cases. Moreover, the FEVAR cohort had significantly greater sac shrinkage and improved aortic remodeling. The suprarenal seal zone in FEVAR may confer a previously undescribed increased level of protection against infrarenal neck dilation and lessen endotension, resulting in more rapid and dramatic sac shrinkage and contributing to a more durable aortic repair.TableDemographics, radiographic data, and outcomes of fenestrated endovascular aneurysm repair (FEVAR) vs endovascular aneurysm repair (EVAR)FEVAREVARP valueDemographics No. of patients20201 Longest CT follow-up, months29.3 ± 16.129.8 ± 16.1.922 Age at procedure, years75.4 ± 9.6775.35 ± 7.07.985 Male85100.231 CAD55501 COPD2510.407 DM1025.407 HTN80801 Active smoker2510.407 Preoperative creatinine level, mg/dL1.06 ± 0.191.07 ± 0.22.88Baseline radiographic data Diameter at lowest renal, mm29.2 ± 7.1924.6 ± 2.94.012 Mean device diameter, mm30.1 ± 3.728.1 ± 3.8.098 Mean device oversizing11.614.3.354 Infrarenal neck length, mm6.65 ± 5.0435.32 ± 14.77<.0001 Nonparallel neck shape8550.041 Severe neck thrombus2010.661 Severe neck calcification551 Length of proximal sealing, mm33.37 ± 9.4531.21 ± 9.19.496 AAA maximum diameter, mm60.44 ± 10.2358.95 ± 11.09.662 AAA length, mm97.12 ± 27.5173.96 ± 18.43.003Diameter changes CA42.22 SMA93.5.0098 +20 mm9.92.7.0008 +15 mm9.92.3.001 +10 mm12.46.2.002 +5 mm13.15.9.002 Lowest renal10.45.9.26 −5 mm9.911.1.77 −10 mm6.712.9.13 −15 mm1.714.3.0009 −20 mm2.116.6.03 AAA maximum diameter−15.7−4.9.04Distance changesCA to aneurysm29.93.4.0167CA to TOG11.713.4.85Outcomes Type IA endoleak on follow-up00N/A Type II endoleak on follow-up3545.748 Branch vessel occlusion00N/A Device-related reintervention1051 All-cause mortality10151 Aorta-related mortality00N/AAAA, Abdominal aortic aneurysm; CA, celiac artery; CAD, coronary artery disease; COPD, chronic obstructive pulmonary disease; CT, computed tomography; DM, diabetes mellitus; HTN, hypertension; N/A, not applicable; SMA, superior mesenteric artery; TOG, top of graft.Categorical variables are presented as percentage. Continuous variables are presented as mean ± standard deviation. Open table in a new tab

In Situ Reconstruction With Custom-Made Bovine Pericardial Grafts for Aortic Graft Infections and Infected Aortic Aneurysms

Graft infections are rare, but serious, complications of vascular surgeries, and the most appropriate material for reconstruction has continued to be debated. The aim of the present study was to evaluate the results of in situ aortic reconstruction with custom-made bovine pericardial grafts. A retrospective analysis was performed for all patients who had undergone in situ aortic reconstruction with custom-made bovine pericardial tube grafts from January 2009 to February 2020 at our academic tertiary center. Complete excision of the infected graft or aortic segment, extensive debridement, and in situ reconstruction with bovine pericardial grafts were applied in all patients. Perioperative and mid-term outcomes, including mortality and freedom of reinfection, were analyzed. A bovine pericardial graft was used in 31 patients (71% male), with a median age of 69 years (range, 46-88 years) to reconstruct the descending thoracic aorta (n = 3), thoracoabdominal aorta (n = 1), and abdominal aorta (n = 27). Of the 31 patients, 16 (51%) were treated for infection of the native aorta and 15 (49%) for prosthetic graft infection. The 30-day mortality was 9.7%. Three cases of reinfection after bovine reconstruction were observed in our cohort and had developed because of recurrent aortoduodenal fistulas. Limb graft occlusions were detected in two cases during follow-up. The outcomes associated with custom-made bovine pericardial grafts compare favorably with those of more traditional treatment modalities. It can be used as an alternative technique when replacing aortoiliac segment in patients with aortic graft infections and infected aortic aneurysms, if other options are not recommended or not possible. It is associated with good patency, a low reinfection rate, and acceptably low early mortality rate. Its ease of use and the rapidity of prosthesis construction have made it the material of choice at our institution.

Finite element modeling to predict procedural success of thoracic endovascular aortic repair in type A aortic dissection.

ObjectiveThoracic endovascular aortic repair (TEVAR) is recommended for type B aortic dissection and recently has even been used in selected cases of proximal (Stanford type A) aortic dissections in scenarios of prohibitive surgical risk. However, mechanical interactions between the native aorta and stent-graft are poorly understood, as some cases ended in failure. The aim of this study is to explore and better understand biomechanical changes after TEVAR and predict the result via virtual stenting.MethodsA case of type A aortic dissection was considered inoperable and selected for TEVAR. The procedure failed due to stent-graft migration even with precise deployment. A novel patient-specific virtual stent-graft deployment model based on finite element method was employed to analyze TEVAR-induced changes under such conditions. Two landing positions were simulated to investigate the reason for stent-graft migration immediately after TEVAR and explore options for optimization.ResultsSimulation of the actual procedure revealed that the proximal bare metal stent pushed the lamella into the false lumen and led to further stent-graft migration during the launch phase. An alternative landing position has reduced the local deformation of the dissection lamella and avoided stent-graft migration. Higher maximum principal stress (>20 KPa) was found on the lamella with deployment at the actual position, while the alternative strategy would have reduced the stress to <5 KPa.ConclusionsVirtual stent-graft deployment simulation based on finite element model could be helpful to both predict outcomes of TEVAR and better plan future endovascular procedures.

Impact of Thoracic Endografting on the Hemodynamics of the Native Aorta: Pre- and Postoperative Assessments of Wall Shear Stress and Vorticity Using Computational Fluid Dynamics

Purpose To quantify the hemodynamic consequences of thoracic endovascular aortic repair (TEVAR) by comparing the preoperative and postoperative wall shear stress (WSS) and vorticity profiles on computational fluid dynamics (CFD) simulations. Materials and Methods The pre- and postoperative computed tomography (CT) scans from 20 consecutive patients (median age 69 years, range 20–87) treated for different thoracic aortic pathologies (11 aneurysms, 5 false aneurysms, 3 penetrating ulcers, and 1 traumatic aortic rupture) were segmented to construct patient-specific CFD models using a meshless code. The simulations were run over the cardiac cycle, and the WSS and vorticity values measured at the proximal and distal landing zones were compared. Results The CFD runs provided 4-dimensional simulations of blood flow in all patients. WSS and vorticity profiles at the proximal landing zone (located in zones 0–3 in 15 patients) varied in 18 and 20 of the cases, respectively; WSS was increased in 11 cases and the vorticity in 9. Pre- and postoperative WSS median values were 4.19 and 4.90 Pa, respectively. Vorticity median values were 40.38 and 39.17 Hz, respectively. Conclusion TEVAR induces functional alterations in the native thoracic aorta, though the prognostic significance of these changes is still unknown. CFD appears to be a valuable tool to explore aortic hemodynamics, and its application in a larger series would help define a predictive role for these hemodynamic assessments.

A strobe multicenter descriptive study of 55 infectious aortitis.

Infectious aortitis (IA) is a rare and severe disease. The treatment classically associates open surgery with prolonged antibiotic therapy. This study aimed to describe clinical characteristics, medical and surgical supports in a large and current series of IA.We conducted a retrospective multicenter study of native aorta IA, between 2000 and 2019. Inclusion criteria were the presence of a microorganism on blood culture, aortic sample or any other validated technique and structural anomaly in imaging.We included 55 patients (85% men), with a median age of 65. Microbiology data substantially differed from previous studies with 12 Gram-negative rods IA, of which only 3 due to Salmonella spp., 24 Gram-positive cocci IA of which 12 Streptococcus spp., and 18 IA due to intracellular growth and/or fastidious microorganisms, of which 8 Coxiella burnetii, 3 Treponema pallidum, and 5 tuberculosis suspicious cases. Fifteen patients (27%) presented with thoracic IA, 31 (56%) with abdominal IA, and 9 (16%) with thoraco-abdominal IA. Eight patients had no surgery, 41 underwent open surgery, only 4 endovascular aneurysm repair, and 2 a combination of these 2 techniques. Nine patients died before 1-month follow-up. There was no difference in the mortality rate between the different types of germ or localization of IA.The variety of germs involved in IA increases. Positron emission tomography-computed tomography scan is a very useful tool for diagnosis. Surgery is still mainly done in open approach and a prospective multicenter study seems necessary to better determine the place of endovascular aneurysm repair versus open surgery.

The Effect of Mechanical Properties of Synthetic Prostheses Made by Electrospinning on the Results of Experimental Implantation in the Infrarenal Abdominal Aorta

The research aims to study the effect of circumferential compliance of synthetic vascular prostheses on their healing during implantation in the infrarenal abdominal aorta of pigs. In an experiment, 12 pigs were implanted with blood vessel prostheses in the infrarenal abdominal aorta. The prostheses possessed elastic characteristics obtained by a tensile testing machine, and differed in circumferential compliance: rigid (polycaprolactone [PCL]); less compliant than the native aorta (polyurethane [PU]); comparable in compliance to the native aorta (copolymer of vinylidene fluoride with hexafluoropropylene) before (FKM) and after radiation treatment (FKM-γ). The implanted prostheses compliance was measured by aortography during the first 3days and 1month after implantation, the condition of the prosthesis capsule was evaluated by macroscopic preparations and histologic examination. Pulsation on PCL prostheses was nonexistent immediately after implantation. On PU prostheses, slight pulsation was noted during the first 3days and disappeared after 1month. On FKM prostheses, although pulsation persisted after 1month, a significant expansion of prostheses was also recorded as a result of fatigue plastic deformation. On FKM-γ prostheses, pulsation comparable in magnitude with aortic pulsation was present 1month after implantation with no change in the size of the prosthesis. Macroscopic preparations reveal significant differences in the formed connective tissue capsule. The PCL prosthesis capsule is thick, narrowing the lumen of the vessel from the outside. The outer surface of PU prostheses is covered with a thinner uniform fibrous capsule. The inner surface of the FKM and FKM-γ prostheses is covered with a thin layer of smooth whitish tissue. The FKM prosthesis, unlike the FKM-γ prosthesis, is sharply expanded. In all cases, moderate aortic expansion was observed distal to the prosthesis. According to the histologic data, the outer and inner capsules of PCL prostheses are covered with a thick layer of fibrous tissue with signs of productive inflammation and foci of calcification. PU prostheses are surrounded by a thick connective tissue capsule partially endothelialized from the inside; the outer capsule is randomly populated with fibroblastic cells. FKM prostheses have a thin outer capsule where smooth muscle cells are visible, mainly oriented along and across the prosthesis axis; the inner capsule is thin and completely covered with a layer of endothelial cells from the side of the lumen. A layered structure is visible in the prosthesis capsule of FKM-γ, and the fibroblast cells in each layer of the capsule are oriented along or across the prosthesis axis, similar to the structure of a natural arterial vessel. The inner surface of the prosthesis is completely endothelialized. The healing and degree of inflammation in a capsule of blood vessel prostheses implanted in the infrarenal abdominal aorta of pigs depend on the degree of their circumferential compliance. Although maintaining pulsations, the cellular structure of the capsule is characterized by a greater degree of differentiation and approaches the structure of the native arterial wall.

An Eligible Surgical Repair Technique for Bland-White-Garland Syndrome

Anomalous origin of left coronary artery from pulmonary artery (ALCAPA) is an uncommon but major congenital cardiac anomaly, which was firstly defined in 1866. Multiple surgical techniques intend to compose 2-coronary artery system, including direct reimplantation of left coronary artery to aorta and coronary artery bypass grafting procedures. Left coronary artery seldomly rises from non-facing pulmonary sinus, where direct reimplantation is technically quite difficult for surgical correction because of long distance from native aorta. In this case report, a surgical technique option of reconstructing left coronary artery, arising from non-facing sinus which we turned to aorta with a tunnel created from autologous pulmonary artery wall, was presented.

The frozen elephant trunk technique in acute DeBakey type I aortic dissection.

Although advances in the field of cardiovascular surgery have improved outcomes for patients with acute DeBakey type I aortic dissection, postoperative in-hospital mortality and morbidity remain substantial. The frozen elephant trunk technique has become a treatment option for this disease and was developed primarily to extend repair into the proximal descending thoracic aorta during aortic arch repair (because the descending thoracic aorta is largely inaccessible via median sternotomy), thus avoiding, delaying, or facilitating subsequent repair of residual native aorta. In this review, we discuss the evidence for and future development of frozen elephant trunk reconstruction for acute DeBakey type I aortic dissection.

Fenestrated and Branched Thoraco-abdominal Endografting after Previous Open Abdominal Aortic Repair

Proximal para-anastomotic aneurysms, or aneurysmal degeneration of the native aorta above a previous open abdominal aortic repair (Pr-AAAs), are challenging scenarios. The aim of this study was to report the early and mid term outcomes of endovascular repair of Pr-AAAs by fenestrated and branched endovascular aneurysm repair (FB-EVAR). From 2006 to 2017, pre-operative, intra-operative, and post-operative data from patients undergoing FB-EVAR for Pr-AAAs at two European vascular surgery units were prospectively collected and retrospectively analysed. Early results were considered in terms of technical success (target visceral vessel cannulation and stenting, absence of type I - III endoleak, iliac limb occlusion and 24h mortality); spinal cord ischaemia (SCI) and 30 day and in hospital mortality. Survival, target visceral vessel (TVV) patency, and freedom from re-interventions were also considered at the mid term follow up. Five hundred and forty-four patients underwent FB-EVAR to treat juxta/pararenal or thoraco-abdominal aneurysms. Of these patients, 108 (19.8%) cases were Pr-AAAs (94% male; mean±standard deviation [SD] age 71±4 years; American Society of Anesthesiologists' grade 3-4 in 74% and 26%, respectively). The previous open aortic repair (OR) was performed 10±2 years before FB-EVAR. It was a tubular aorto-aortic repair in 63 (58.3%) cases, a bifurcated aortobi-iliac repair in 37 (34.2%) cases, and an aortobifemoral bypass repair in eight (7.4%) cases. A previous thoracic endovascular aneurysm repair (TEVAR) had been performed in seven patients (6.5%). The aortic lesion at the time of FB-EVAR was, according to the Crawford classification, a type I - III in 69 (63.9%) or a type IV 39 (36.1%) thoraco-abdominal aneurysm. The mean±SD aneurysm diameter was 64±6mm. Overall, 390 TVVs (3.6±1 TVV/case) were revascularised by an endograft with fenestrations (n=63 [58.3%]), with branches (n=26 [24.1%]), or with both fenestrations and branches (n=19 [17.6%]). Tubular, trimodular, or aorto-uni-iliac implants were planned in 68 (63.0%), 38 (35.2%), and two (1.8%) patients, respectively. Proximal TEVAR, carotid-subclavian bypass, and iliac branch devices were planned as adjunctive procedures in 41 (38.0%), five (4.6%), and three (2.8%) cases, respectively. Overall technical success was 93%, with technical failures including five TVV losses (coeliac trunk, n=1; renal arteries, n=4) and three deaths within 24h. Post-operative SCI occurred in seven patients (6.5%), four of which (3.7%) were permanent. SCI was more frequent in category I - III TAAAs (p=.042) and in endografts incorporating both fenestrations and branches (p=.023). Cardiac, pulmonary, and renal complications (reduction in glomerular filtration rate of ≥30% compared with baseline) occurred in 9%, 10%, and 20%, respectively. Bowel ischaemia was seen in three (2.8%) patients. Thirty day mortality was 4% and was associated with pre-operative chronic renal failure (p=.034), post-operative cardiac morbidity (p=.041), and bowel ischaemia (p=.003). Overall in hospital mortality was 5.5% (n=6). Mean±SD follow up was 38±18 months. Survival was 82%, 64%, and 54% at one, three, and five years, respectively, and target visceral vessel patency was 93%, 91%, and 91%, respectively. Permanent haemodialysis was needed in four patients (3.7%). There was no late aneurysm related mortality. Survival during follow up was statistically significantly affected by pre-operative chronic renal failure (p=.022), post-operative cardiac morbidity (p=.042), SCI (p=.044), and bowel ischaemia (p=.003). Freedom from re-intervention at one, three, and five years was 89%, 77%, and 74%, respectively. Endovascular treatment of aneurysmal aortic degeneration above a previous open abdominal repair with FB-EVAR is safe and effective. If those promising results are confirmed at later follow up, FB-EVAR should be considered a prominent therapeutic option, especially in high risk patients.