A Radiation-Crosslinked Gelatin Hydrogel That Promotes Tissue Incorporation of an Expanded Polytetrafluoroethylene Vascular Graft in Rats.

A prosthetic vascular graft that induces perigraft tissue incorporation may effectively prevent serious sequelae such as seroma formation and infection. Radiation-crosslinked gelatin hydrogel (RXgel) mimics the chemical and physical properties of the in vivo extracellular matrix and may facilitate wound healing by promoting tissue organization. Fibroblasts cultured on RXgel actively migrated into the gel for up to 7 days. RXgels of three different degrees of hardness (Rx[10], soft; Rx[15], middle; Rx[20], hard) were prepared, and small disc-like samples of RXgels were implanted into rats. In vitro and in vivo results indicated that Rx[10] was too soft to coat vascular grafts. Thus, expanded polytetrafluoroethylene (ePTFE) vascular grafts coated with RXgel were developed using Rx[15] and Rx[20] gels, and ring-shaped slices of the graft were implanted into rats. Alpha-smooth muscle actin (αSMA) and type III collagen (Col-III) levels were detected by immunohistochemistry. Immunohistochemical staining for αSMA and Col-III demonstrated that RXgel-coated vascular grafts induced more granulation tissue than non-coated grafts on days 14 and 28 after implantation. RXgel-coated ePTFE vascular grafts may provide a solution for patients by reducing poor perigraft tissue incorporation.

European registry of type A aortic dissection (ERTAAD) - rationale, design and definition criteria.

BACKGROUND: Acute Stanford type A aortic dissection (TAAD) is a life-threatening condition. Surgery is usually performed as a salvage procedure and is associated with significant postoperative early mortality and morbidity. Understanding the patient's conditions and treatment strategies which are associated with these adverse events is essential for an appropriate management of acute TAAD. METHODS: Nineteen centers of cardiac surgery from seven European countries have collaborated to create a multicentre observational registry (ERTAAD), which will enroll consecutive patients who underwent surgery for acute TAAD from January 2005 to March 2021. Analysis of the impact of patient's comorbidities, conditions at referral, surgical strategies and perioperative treatment on the early and late adverse events will be performed. The investigators have developed a classification of the urgency of the procedure based on the severity of preoperative hemodynamic conditions and malperfusion secondary to acute TAAD. The primary clinical outcomes will be in-hospital mortality, late mortality and reoperations on the aorta. Secondary outcomes will be stroke, acute kidney injury, surgical site infection, reoperation for bleeding, blood transfusion and length of stay in the intensive care unit. DISCUSSION: The analysis of this multicentre registry will allow conclusive results on the prognostic importance of critical preoperative conditions and the value of different treatment strategies to reduce the risk of early adverse events after surgery for acute TAAD. This registry is expected to provide insights into the long-term durability of different strategies of surgical repair for TAAD. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04831073 .

Preemptive Femoral-Femoral Crossover Grafting of Artery and Vein Before Pelvic Exenterative Surgery for Locally Advanced and Recurrent Pelvic Malignancy Involving the Aortoiliac Axis.

INTRODUCTION: Achieving a negative resection through a pelvic exenteration for a recurrent or an advanced pelvic malignancy offers the potential for cure. Exenterative surgical units have expanded the boundaries and redefined what constitutes resectable disease through improved surgical technique. In selected cases, contiguous tumor involvement of the aortoiliac axis requires en bloc resection and subsequent vessel reconstruction. However, vascular reconstruction can be challenging in a contaminated field during an extended radical resection. TECHNIQUE: The aim of this Technical Note is to describe a novel method in the management of patients with recurrent or advanced pelvic malignancy involving the aortoiliac axis by performing preemptive femoral-femoral arterial and venous crossover grafts, with adjunctive arteriovenous loop fistula formation before undergoing an extended radical pelvic resection 4 weeks later. RESULTS: Four patients have undergone preemptive femoral-femoral arterial and venous crossover grafts at our institution (median age = 60 y (range, 47-66 y); 2 women). There were no early complications, and all of the patients subsequently underwent extended radical pelvic resections for a pelvic malignancy. CONCLUSIONS: Preemptive vascular reconstruction before major pelvic surgery reduces the risk of graft infection because this method avoids the wounds being contaminated by GI or genitourinary organisms. Other advantages to this technique include a reduction in the overall operating time for the pelvic exenteration, a significant reduction in the ischemia time to the lower limbs, and ensuring that the grafts are patent before embarking on major intra-abdominal surgery.

Endovascular Repair of Aortic Dissection Involving the Left Subclavian Artery by Castor Stent Graft: A Multicentre Prospective Trial.

OBJECTIVE: The left subclavian artery (LSA) origin can be intentionally covered by stent grafts, to provide adequate proximal landing zones during thoracic endovascular repair for Stanford type B aortic dissections (TBADs). To preserve the LSA, a novel single branched stent graft, named "Castor" was designed and a clinical trial conducted to investigate its suitability. METHODS: From April 2013 to March 2015, 73 patients with TBAD were treated by Castor stent grafts at 11 Chinese tertiary hospitals as part of a single arm prospective clinical trial. There were 50 acute (<2 weeks [68.5%]) and 23 chronic aortic dissections (>2 weeks [31.5%]). RESULTS: The technical success rate was 97% (n = 71/73). The two failures were caused by occlusion of the branch section of the stent graft. There were four intra-operative endoleaks (two type Ia, two type B from the LSA). The endoleak rate was 5% (n = 4/73). There was one in hospital death and no major complications. The median follow up time was 61 months (range 48-72 months). The mortality was 5% (n = 4/73) within one year and 7% within six years (n = 5/73). Two deaths were of unknown cause and three were not related to the aorta. Two new entry tears were found on the proximal or distal edge of the stent graft and were retreated endovascularly. Six occlusions of the branch section of the Castor stent graft were found, and the follow up patency rate of the branch section was 93% (n = 63/68). Two intra-operative endoleaks were left during follow up and eventually disappeared according to the latest computed tomography angiograms. CONCLUSION: For patients with TBADs needing anchoring proximal to the origin of LSA, the Castor single branched stent graft may provide an easily manipulated, safe, and effective endovascular treatment.

Anatomic Suitability for Branched Thoracic Endovascular Repair in Patients with Aortic Arch Pathological Features.

Background Endovascular repair has become a viable alternative for aortic pathological features, including those located within the aortic arch. We investigated the anatomic suitability for branched thoracic endovascular repair in patients previously treated with conventional open surgery for aortic arch pathological features. Methods and Results Patients who underwent open surgery for aortic arch pathological features at our institution between 2000 and 2018 were included. Anatomic suitability was determined by strict compliance with the anatomic criteria within manufacturers' instructions for use for each of the following branched thoracic stent grafts: Relay Plus Double-Branched (Terumo-Aortic), TAG Thoracic Branch Endoprosthesis (W.L. Gore & Associates), Zenith Arch Branched Device (Cook-Medical), and Nexus Stent Graft System (Endospan Ltd/Jotec GmbH). Computed tomography angiography images were analyzed with outer luminal line measurements. A total of 377 patients (mean age, 64±14 years; 64% men) were identified, 153 of whom had suitable computed tomography angiography images for measurements. In total, 59 patients (15.6% of the total cohort and 38.6% of the measured cohort) were eligible for endovascular repair using at least one of the devices. Device suitability was 30.9% for thoracic aneurysms, 4.6% for type A dissections, 62.5% for type B dissections, and 28.6% for other pathological features. Conclusions The anatomic suitability for endovascular repair of all aortic arch pathological features was modest. The highest suitability rates were observed for thoracic aneurysms and for type B dissections, of which repair included part of the aortic arch. We suggest endovascular repair of arch pathological features should be reserved for high-volume centers with experience in endovascular arch repair.

Long-Term Results After Drug-Eluting Versus Bare-Metal Stent Implantation in Saphenous Vein Grafts: Randomized Controlled Trial.

Background Efficacy data on drug-eluting stents (DES) versus bare-metal stents (BMS) in saphenous vein grafts are controversial. We aimed to compare DES with BMS among patients undergoing saphenous vein grafts intervention regarding long-term outcome. Methods and Results In this multinational trial, patients were randomized to paclitaxel-eluting or BMS. The primary end point was major adverse cardiac events (cardiac death, nonfatal myocardial infarction, and target-vessel revascularization at 1 year. Secondary end points included major adverse cardiac events and its individual components at 5-year follow-up. One hundred seventy-three patients were included in the trial (89 DES versus 84 BMS). One-year major adverse cardiac event rates were lower in DES compared with BMS (2.2% versus 16.0%, hazard ratio, 0.14; 95% CI, 0.03-0.64, P=0.01), which was mainly driven by a reduction of subsequent myocardial infarctions and need for target-vessel revascularization. Five-year major adverse cardiac event rates remained lower in the DES compared with the BMS arm (35.5% versus 56.1%, hazard ratio, 0.40; 95% CI, 0.23-0.68, P<0.001). A landmark-analysis from 1 to 5 years revealed a persistent benefit of DES over BMS (hazard ratio, 0.33; 95% CI, 0.13-0.74, P=0.007) in terms of target-vessel revascularization. More patients in the BMS group underwent multiple target-vessel revascularization procedures throughout the study period compared with the DES group (DES 1.1% [n=1] versus BMS 9.5% [n=8], P=0.013). Enrollment was stopped before the target sample size of 240 patients was reached. Conclusions In this randomized controlled trial with prospective long-term follow-up of up to 5 years, DES showed a better efficacy than BMS with sustained benefits over time. DES may be the preferred strategy in this patient population. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT00595647.

Right subclavian artery cannulation for aortic dissection surgery, without infraclavicular incision.

The choice of arterial cannulation strategy for acute type A dissection surgery remains a controversial  issue and a subject of great debate because of its impact on clinical outcomes. A review of retrospective studies shows that surgeons are tending to switch from a retrograde to an antegrade perfusion strategy. Innominate artery cannulation has a number of advantages when compared to other cannulation techniques; however when the vessel is dissected, the proximal right subclavian artery can be used for arterial return. Also, because cannulation of the right subclavian artery does not require a second surgical incision in addition to median sternotomy, this decreases the number of incision sites and further simplifies the procedure.

Compliance of Textile Vascular Prostheses Is a Fleeting Reality.

OBJECTIVE: Compliance is considered to be a major property influencing the long term performances of synthetic vascular substitutes that could play a role in anastomotic false aneurysm and intimal hyperplasia stenosis onset. Over the last decades, manufacturers have tried to develop substitutes that mechanically mimic arterial properties and avoid a compliance mismatch at the anastomoses in particular. However, data are missing about how initial compliance properties could change with time. The goal of this study was to evaluate how the compliance of vascular grafts evolves under cyclic loading conditions in vitro. METHODS: The compliance of three different models of commercially available textile polyethylene terephthalate (PET) grafts was evaluated. Tests were performed with and without their original coating. Compliance was assessed with a specific device dedicated to measure the deformations undergone by a graft under cyclic pressure loading conditions, using image analysis software. In each experiment, image analysis was performed under 60 and 140 mmHg pressure loading conditions at loading start (H0) and after three, six, and 24 h (H3, H6, H24) loading time. Average radial, longitudinal, and volumetric compliance was calculated from the obtained images. RESULTS: Twenty-four samples were tested. Results demonstrate that all values decreased significantly within only a few hours. On average, the loss of compliance after 3 h of cyclic loading ranged on average from 35% for longitudinal compliance to 39% for radial compliance and 37% (p < .050) for volume compliance. After 24 h, the loss of radial, longitudinal and volume compliance was respectively 63 ± 3%, 60.5 ± 2% and 61 ± 7%. CONCLUSION: In this in vitro model, PET graft compliance has already decreased significantly within 3 h. The rapid loss of compliance identified in this experimental study helps explain the mismatch mentioned in clinical observations.

Application of a clampless hemostatic device (HeartString®) for outflow graft anastomosis.

Performing an aortic anastomosis with a prosthetic graft (e.g. for left ventricular assist device implantation or veno-arterial extracorporeal membrane oxygenation) requires side-clamping of the aorta. Clamping of aorta is particularly challenging in redo cases and/or in patients with a short ascending aorta and open coronary artery bypass grafts, or atherosclerotic disease of the aorta. In this video tutorial, we provide a thorough description of the surgical technique for applying the HeartString® Proximal Seal System (MAQUET Holding B.V. & Co. KG, Rastatt, Germany) for the anastomosis of the aorta with a prosthesis graft. The feasibility of using the HeartString® device has been demonstrated and no procedure-related complications were experienced.

Evaluation of a hybrid small caliber vascular graft in a rabbit model.

OBJECTIVE: A hybrid small-caliber artificial vascular graft based on bilayer porcine small intestinal submucosa (SIS) with curdlan and dipyridamole mixture film serving as the so-called sandwich filler was developed for biological performance evaluation. We evaluated the performance of the graft and filler. METHODS: SIS was coated with heparin by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. Curdlan acted as the carrier of dipyridamole. Three types of graft tubes (2 mm internal diameter and 20 mm in length) were manufactured: bilayer SIS with 10% curdlan + 10% dipyridamole mixture film (SCD), bilayer SIS with 10% curdlan film (SC), and monolayer SIS (S). The remodeling characteristics of the grafts were evaluated by implanting them as bypass in rabbit carotid arteries for 2 and 3 months. Each group contained 16 rabbits, and 16 nonsurgical rabbits served as the control group. RESULTS: Eight rabbits of each group, including the graft occluded group, were killed at 2 months and the others were killed at 3 months. Follow-up showed that all 8 grafts in SCD group were patent at 2 months. Six of 16 grafts in the SC group and 5 of 16 grafts in the S group were occluded at 2 months. One of 8 SCD grafts were occluded at 3 months and the patent showed a confluent endothelium without intimal hyperplasia. The neointima layer was composed of circumferentially aligned vascular smooth muscle cells. At 3 months, SC and S group grafts showed incomplete endothelialization and varying degrees of mural thrombus, accompanied by occlusion in the SC group (3 of 8) and S group (2 of 8). CONCLUSIONS: The novel hybrid small caliber artificial vascular graft exhibited an improvement in revascularization resulting in high patency rate.

Application of Baseline Clinical and Morphological Parameters for Prediction of Late Stent Graft Related Endoleaks after Endovascular Repair of Abdominal Aortic Aneurysm.

OBJECTIVES: To evaluate the influence of baseline clinical and morphological parameters on the occurrence of a late stent graft related endoleak (srEL; types 1 and 3) after endovascular aneurysm repair (EVAR). METHODS: This is a retrospective case control study of patients who were routinely followed up after EVAR of abdominal aortic aneurysms. Pre-interventional, pre-discharge, and last available multislice computed tomography angiogram (MSCTA) of 279 patients were analysed. Stent graft related endoleaks detected by follow up MSCTA at least six months after EVAR were specified as late srEL. Baseline demographic characteristics and morphological variables were derived from the pre-interventional and pre-discharge MSCTA. Univariable and multivariable analysis with a Cox proportional hazards model were used to determine baseline factors associated with the occurrence of a late srEL. RESULTS: Twenty-four (8.6%) of 279 patients suffered a late srEL, during a mean MSCTA follow up of 30.9 ± 25.8 (23.5, IQR 10.6-42.8) months. In the univariable analysis, age (hazard ratio [HR] 1.09; p = .001), female sex (HR 3.25; p = .014), right iliac sealing diameter (HR 10.04; p = .03), left iliac sealing diameter (HR 8.65; p = .001), infrarenal aortic neck angulation (HR 1.02; p = .011), and suprarenal fixation level (HR 3.47; p = .014) were significantly associated with an increased incidence of late srEL. Age (HR 1.08; p = .012), female sex (HR 2.72; p = .049), and left iliac sealing diameter (HR 4.48; p = .033) proved to be risk factors significantly associated with a higher incidence of late srEL in multivariable analysis. CONCLUSIONS: Older patients, those with female gender, and those with larger left iliac sealing diameters seem to experience higher rates of late srEL. Independent confirmation of these must be addressed in larger studies.

Outcomes of Endovascular Repair for Abdominal Aortic Aneurysms: A Nationwide Survey in Japan.

OBJECTIVE: To analyze data on patients treated with a bifurcated stent graft for abdominal aortic aneurysm (AAA). BACKGROUND: The Japan Committee for Stentgraft Management (JACSM) was established in 2007 to manage the safety of endovascular aortic aneurysm repair (EVAR) in Japan. The JACSM registry includes detailed anatomical and clinical data of all patients who undergo stent graft insertion in Japan. METHODS: Among 51,380 patients treated with bifurcated stent graft for AAA, we identified 38,008 eligible patients (excluding those with rupture or insufficient data). The analyzed factors included age, sex, comorbidities, AAA pathology and etiology, aneurysm and neck diameters, 7 anti-instructions for use (IFU) factors, and endoleaks at hospital discharge. The endpoints were death, adverse events, sac dilatation (≥5 mm), and reintervention. RESULTS: The rates of intraoperative and in-hospital mortality were 0.08% and 1.07%, respectively. Infectious aneurysm and pseudo-aneurysm were associated with overall survival and reintervention. Older age, large aneurysm diameter, and all types of persistent endoleaks were strong predictors of adverse events, sac dilatation, and reintervention. Comorbid cerebrovascular disease, renal dysfunction, and respiratory disorders were also risk factors. In total, 47.6% of patients violated the IFU; among the anti-IFU factors assessed, poor access and severe neck calcification were strong risk factors for mortality, reintervention, and adverse events. The sac dilatation rate at 5 years was 23.3%. CONCLUSIONS: Although the analysis included EVAR with poor anatomy, the perioperative mortality rate was acceptable compared with that in previous large population studies.

Long-term outcomes of total arch replacement using a 4-branched graft.

OBJECTIVE: Our study evaluated the long-term outcomes of total arch replacement using a 4-branched graft. METHODS: From October 1999 to December 2016, 655 patients underwent total arch replacement using a 4-branched graft (pathology in the 655 patients was distributed as 399 no dissection, 149 acute dissection, and 107 chronic dissection). Two hundred nine patients (31.9%) underwent nonelective surgery. Mean follow-up term was 5.0 ± 4.1 years and follow-up rate was 97.1%. RESULTS: Of 655 patients who underwent total arch replacement using a 4-branched graft, operative mortality occurred in 34 patients (5.2%) and permanent neurologic deficit occurred in 24 patients (3.7%). One hundred ninety late deaths occurred, with 20 aortic event-related deaths. Overall survival was 73.1% ± 1.9% at 5 years and 54.8% ± 2.7% at 10 years. Multivariate Cox-hazard regression analysis demonstrated that older age, lower estimated glomerular filtration rate, concurrent procedures, permanent neurologic deficit, tracheostomy, and renal failure were significant risk factors for late death. Freedom from repeat operation on the aorta was 98.0% ± 0.7% at 5 years and 93.9% ± 1.8% at 10 years and freedom from additional aortic operation was 87.2% ± 1.5% at 5 years and 77.3% ± 2.7% at 10 years. The incidence of pseudoaneursym was 2.2%. CONCLUSIONS: The long-term outcomes for patients undergoing total arch replacement using 4-branched graft are favorable. However, even in the late phase, periodic follow-up is necessary to address subsequent aorta-related events.

Three-year efficacy and patency follow-up of decellularized human internal mammary artery as a novel vascular graft in animal models.

BACKGROUND: Various investigations have reported that the internal mammary artery (IMA) is an efficient and functional choice of conduit for vascular graft surgeries, especially for coronary artery bypass grafts; however, the quest to find an ideal vascular substitute remains. We hypothesized that acellular IMA could be an appropriate graft for small-diameter vascular bypasses that could be used in various surgeries including coronary artery bypass grafting. METHODS: We decellularized human IMAs and performed histologic evaluations and scanning electron microscopy to confirm the decellularization process and the preservation of the extracellular matrix. Subsequently, we grafted the scaffolds into the superficial femoral arteries of 8 New Zealand rabbits with an end-to-end anastomosis. Computed tomography angiograms were provided at 3, 12, and 36 months postoperatively. Subsequently, the animals were killed, and biopsies were taken for histologic and immunohistochemical assessments. RESULTS: Evaluation of the acellular tissue confirmed the efficacy of the decellularization protocol and the preservation of the extracellular matrix. All 8 animals survived the entire follow-up period. Doppler ultrasonography and computed tomography angiographies verified the conduit's patency. Histologic assessments depicted the recellularization of all 3 layers of the scaffold. Smooth muscle cells were detected in tunica media. Immunohistochemical assessments confirmed these findings. CONCLUSIONS: In conclusion, we demonstrated that acellular human IMA could be used as an efficient small-diameter vascular substitute with high patency. These findings could pave the path for future investigations on the clinical application of acellular IMA as a novel vascular graft for small-diameter bypass surgeries.

Double aortic central cannulation for open thoracoabdominal aorta repair.

Establishment of extracorporeal circulation during open descending and thoracoabdominal aorta repair is necessary in almost all patients. Full cardiopulmonary bypass (CPB) with peripheral cannulation and left heart bypass are the most commonly used circulatory support strategies and they effectively minimize the risk of visceral and central nervous system ischemia. However, both strategies are associated with significant drawbacks. In this video tutorial we present 2 cases demonstrating an alternative strategy for CPB establishment during descending or thoracoabdominal aortic repair. This technique uses two simultaneous (proximal and distal) aortic perfusion cannulas and a single-stage right atrial cannula, both inserted through the main incision. This technique offers all the advantages of full CPB while lowering the risk of proximal hypoperfusion syndrome, and the use of central cannulas virtually eliminates the risk of retrograde perfusion. Complications associated with femoral incision/cannulation are avoided and excellent venous drainage is achieved. This alternative CPB strategy increases the surgical options for extensive thoracoabdominal aortic repair and allows bespoke management for this complex disease.

Usefulness of positron emission tomography/computed tomography in patients with valve-tube graft infection.

OBJECTIVE: Infection of valved aortic grafts is a rare entity whose diagnosis remains challenging. Positron emission tomography (PET)/CT has become a criterion for the diagnosis of infective endocarditis (IE) in prosthetic valves, but its role on ascending aortic graft infections remains unclear. This study aims to assess the diagnostic value of PET/CT in patients with valved aortic graft infection. METHODS: 12 episodes with a valved aortic graft who had undergone a PET/CT due to suspicion of IE were prospectively included (group I) and compared with five controls free of infection who underwent PET/CT for other reasons (group II). Pathological uptake of 18F-fluorodeoxyglucose (FDG) and its pattern at the prosthetic valve and aortic graft were studied. RESULTS: Diagnosis of IE was confirmed in 9 out of 12 episodes of group I. 18F-FDG uptake was detectable in eight out of nine cases with a final diagnosis of IE. The most repeated pattern of uptake was homogeneous around the valve and heterogeneous around the tube. There was one false-negative study. Of the three patients in which IE was ruled out, there were two false positives and one true negative. In group II, there were three patients with a positive PET/CT study, two of them had active aortitis and the third was considered false positive. CONCLUSIONS: 18F-FDG PET/CT shows high sensitivity in the detection of infected aortic grafts. Thus, this technique should be considered in the diagnostic work-up of patients with suspicion of aortic graft infection. However, further validation of this approach is needed.