Open surgical replacement of the descending aorta: single-center experience.

Background: This study presents a single center's experience and analyzes clinical outcomes following elective open surgical descending aortic replacement. Methods: Between January 2000 and August 2019, 96 patients with mean age 64 years (range, 49.5-71 years) (62.5% (n=60) male) underwent elective descending aortic replacement due to aneurysm (n=60) or chronic dissection (n=36). Marfan syndrome was present in 12 patients (12.5%). Results: In-hospital mortality rate was 3.1% (n= 3. 2 in the aneurysm group, 1 in the dissection group). New-onset renal insufficiency postoperatively with (creatinine ≥ 2.5 mg/dl) manifested in 10 patients (10.8%). One patient (1%) suffered from stroke, and paraplegia developed in 1 pts (1%). The median follow-up time was 7 years (IQR: 2.5-13 years). The 5- and 10-year survival rates were 70.8% and 50.7% respectively. We did not observe any early or late prosthetic graft infection. The Cox proportional hazards regression analysis identified age (HR: 1.044, 95% CI: 1.009-1.080, p-value: 0.014), diabetes (HR: 2.544, 95% CI: 1.009-6.413, p-value: 0.048), and chronic obstructive pulmonary disease (COPD) (HR: 2.259, 95% CI: 1.044-4.890, p-value: 0.039) as risk factors for late mortality. Conclusions: This study showed that the elective open surgical replacement of the descending aorta can be achieved with excellent outcomes in terms of perioperative mortality and morbidity. Prosthetic graft is not a problem with open surgical descending aortic replacement, even in the long term. Supplementary Information: The online version contains supplementary material available at 10.1007/s12055-022-01443-x.

The potential impact of coagulation factor XIII in trauma-induced coagulopathy - a retrospective case series analysis.

BACKGROUND: The role of factor XIII (FXIII) in trauma-induced coagulopathy (TIC) is not fully understood. METHODS: We evaluated FXIII supplementation in severely injured patients with persistent bleeding. This was a retrospective case series analysis. RESULTS: Twenty-four patients received FXIII concentrate within 24 h of admission for bleeding that continued after transfusion of > 6 U red blood cells (RBCs); control patients (n = 27) did not receive FXIII concentrate. Both study groups were similar regarding injury severity score and global coagulation tests, but FXIII activity levels were significantly higher and lactate levels significantly lower in the control group, respectively. The differences in FXIII activity between the groups could be attributed to a more severe trauma-induced coagulopathy in FXIII-deficient patients, as demonstrated by lower fibrinogen and higher lactate levels. The median dose of FXIII concentrate within 24 h of admission was 2500 IU (IQR: 1250-4375). Median 24-h transfusion of RBCs (primary study endpoint) was significantly higher in the FXIII group versus controls (10.0 U, IQR 5-14 U vs. 2, IQR 0-6 U; p < 0.01). Subsequently, while patients were in the intensive care unit, there was no statistically significant difference regarding RBC transfusion anymore and the overall clinical outcomes were similar in both patient groups. CONCLUSIONS: The substitution of FXIII in patients who were more seriously compromised due to higher lactate levels and who presented with initially more severe bleedings than patients in the control group, resulted in a comparable transfusion necessity after 24 h. Thus, we guess that the substitution of FXIII in severely injured patients with ongoing bleeding might have an impact on their clinical outcome.

Preliminary application of native Nephila edulis spider silk and fibrin implant causes granulomatous foreign body reaction in vivo in rat's spinal cord.

After spinal cord injury, gliomesenchymal scaring inhibits axonal regeneration as a physical barrier. In peripheral nerve injuries, native spider silk was shown to be an effective scaffold to facilitate axonal re-growth and nerve regeneration. This study tested a two-composite scaffold made of longitudinally oriented native spider silk containing a Haemocomplettan fibrin sheath to bridge lesions in the spinal cord and enhance axonal sprouting. In vitro cultivation of neuronal cells on spider silk and fibrin revealed no cytotoxicity of the scaffold components. When spinal cord tissue was cultured on spider silk that was reeled around a metal frame, migration of different cell types, including neurons and neural stem cells, was observed. The scaffold was implanted into spinal cord lesions of four Wistar rats to evaluate the physical stress caused on the animals and examine the bridging potential for axonal sprouting and spinal cord regeneration. However, the implantation in-vivo resulted in a granulomatous foreign body reaction. Spider silk might be responsible for the strong immune response. Thus, the immune response to native spider silk seems to be stronger in the central nervous system than it is known to be in the peripheral body complicating the application of native spider silk in spinal cord injury treatment.

Vascular procedures in patients with left ventricular assist devices: single-center experience.

OBJECTIVE: A growing number of patients suffering from heart failure is living with a left ventricular assist device (LVAD) and is in the need for non-cardiac surgery. Vascular procedures due to ischemia, bleeding, or other device-related complications may be required and pose a challenge to the caregivers in terms of monitoring and management of these patients. Therefore, we reviewed our experience with LVAD patients undergoing vascular surgery. METHODS: From January 2010 until March 2017, a total of 54 vascular procedures were performed on 41 LVAD patients at our institution. Patient records were reviewed retrospectively in terms of incidence of LVAD-related complications, including thrombosis, stroke, bleeding, wound healing, and survival associated with vascular surgery. The type of surgery was recorded, as well as various clinical demographic variables. RESULTS: Vascular procedures were performed in 35 men (85.4%) and 6 women (14.6%) with LVADs. There were no perioperative strokes, device thromboses, or device malfunctions. Thirty-day mortality overall was 26.8% (eleven patients), with most patients dying within 30 days after LVAD implantation due to multi-organ failure. In 25 procedures (46.3%), a blood transfusion was necessary. CONCLUSION: Patients on LVAD support are a complex cohort with a high risk for perioperative complications. In a setting where device function and anticoagulation are monitored closely, vascular surgery in these patients is feasible with an acceptable perioperative risk.

Distinct systemic cytokine networks in symptomatic and asymptomatic carotid stenosis.

Inflammatory processes are crucial in atherosclerosis and atherothrombosis. This study aimed to identify a cytokine-pattern that is associated with plaque-vulnerability or symptomatic state in comprehensively investigated patients with symptomatic (sCS) and asymptomatic carotid stenosis (aCS). Twenty-two patients with sCS and twenty-four patients with aCS undergoing carotid endarterectomy (CEA) were considered. A cytokine-panel was measured in plasma-specimens prior to surgery and at a 90 day follow-up. Doppler-ultrasound detecting microembolic signals (MES) in the ipsilateral middle cerebral artery was performed. Carotid plaques were analysed regarding histopathological criteria of plaque-vulnerability and presence of chemokine receptor CXCR4. Correction for multiple comparisons and logistic regression analysis adjusting for vascular risk factors, grade of stenosis, antithrombotic and statin pretreatment were applied. In sCS-patients higher plasma-levels of Fractalkine (CX3CL1), IFN-α2, IL-1ß, IL-2, IL-3, IL-7 were found compared to aCS-patients. CXCR4-expression on inflammatory cells was more evident in sCS- compared to aCS-plaques and was associated with vulnerability-criteria. In contrast, plasma-cytokine-levels were not related to CXCR4-expression or other vulnerability-criteria or MES. However, in both groups distinct inter-cytokine correlation patterns, which persisted at follow-up and were more pronounced in the sCS-group could be detected. In conclusion, we identified a distinct cytokine/chemokine-network in sCS-patients with elevated and closely correlated mediators of diverse functions.

Complete Myogenic Differentiation of Adipogenic Stem Cells Requires Both Biochemical and Mechanical Stimulation.

Vascular tissue engineering of the middle layer of natural arteries requires contractile smooth muscle cells (SMC) which can be differentiated from adipose-derived mesenchymal stem cells (ASC) by treatment with transforming growth factor-ß, sphingosylphosphorylcholine and bone morphogenetic protein-4 (TSB). Since mechanical stimulation may support or replace TSB-driven differentiation, we investigated its effect plus TSB-treatment on SMC orientation and contractile protein expression. Tubular fibrin scaffolds with incorporated ASC or pre-differentiated SMC were exposed to pulsatile perfusion for 10 days with or without TSB. Statically incubated scaffolds served as controls. Pulsatile incubation resulted in collagen-I expression and orientation of either cell type circumferentially around the lumen as shown by alpha smooth muscle actin (αSMA), calponin and smoothelin staining as early, intermediate and late marker proteins. Semi-quantitative Westernblot analyses revealed strongly increased αSMA and calponin expression by either pulsatile (12.48-fold; p < 0.01 and 38.15-fold; p = 0.07) or static incubation plus TSB pre-treatment (8.91-fold; p < 0.05 and 37.69-fold; p < 0.05). In contrast, contractility and smoothelin expression required both mechanical and TSB stimulation since it was 2.57-fold increased (p < 0.05) only by combining pulsatile perfusion and TSB. Moreover, pre-differentiation of ASC prior to pulsatile perfusion was not necessary since it could not further increase the expression level of any marker.

Conventional culture diagnostics vs. multiplex PCR for the detection of causative agents of vascular graft infections - results of a single centre observational pilot study.

Background: Timely diagnosis of vascular graft infections is of major importance in vascular surgery. The detection of causative microorganisms is needed for specific medical treatment, but conventional culture is often slow, insensitive and inconclusive due to antibiotic pre-treatment. Detection of bacterial DNA by polymerase chain reaction (PCR) might bypass these problems. We hypothesised that multiplex PCR (mPCR) is feasible, fast and sensitive to detect causative microorganisms in vascular graft infections. Patients and methods: We performed a pilot observational prospective study comparing conventional culture and a commercial mPCR. Inclusion criteria were: confirmed graft infection, suspicious imaging, clinical suspicion, anastomotic aneurysm and repeated graft occlusion. Diagnostic methods were performed using identical samples. Time to result, microorganisms and antibiotic resistance in both groups were compared using Student's t-test or nonparametric tests. Results: 22 samples from 13 patients were assessed and 11 samples were negative for bacteria. Some showed multiple germs. In total, we found 15 different organisms. 13 samples matched, 9 had non-concordant results. Out of the mismatches 3 microorganisms identified in PCR were not detected by culture. Time to result with PCR was shorter (median 5 h vs. 72 h, p < 0.001) than with culture. No resistance genes were detected by mPCR, but conventional culture allowed susceptibility testing and revealed resistance in 5 samples. Conclusions: mPCR seems to be a feasible and quick tool to detect causes of vascular graft infections within 24 h and might be helpful in antibiotic pre-treated patients. The detection of antibiotic resistance with mPCR needs improvement for clinical practice.

Biochemical Myogenic Differentiation of Adipogenic Stem Cells Is Donor Dependent and Requires Sound Characterization.

IMPACT STATEMENT: We here showed that even under optimized conditions for biochemical differentiation of adipose-derived stem cells (with respect to a pronounced marker protein expression for a reasonable period of time) it was not possible to obtain functional smooth muscle cells from all donors. Moreover, an underestimated role may play the effect of the scaffold material on smooth muscle cell functionality. Both aspects are crucial for the successful tissue engineering of the vascular medial layer combining autologous cells with a suitable scaffold material and thus should be thoroughly addressed in each individualized therapeutic approach.

Biocompatibility of Intensified Decellularized Equine Carotid Arteries in a Rat Subcutaneous Implantation Model and in a Human In Vitro Model.

Limited biocompatibility of decellularized scaffolds is an ongoing challenge in tissue engineering. We recently demonstrated that intensified detergent-based decellularization of equine carotid artery (dEACintens) removed residual cellular molecules from the scaffold more efficiently than a conventional decellularization (dEACcon), although this approach did not eliminate its immunogenicity entirely. CCN1 has been shown to improve biocompatibility of dEACcon in a sheep model. In this study, we tested the biocompatibility of dEACintens and dEACcon with or without CCN1 coating after subcutaneous implantation in rats for up to 12 weeks. Explants were assessed by conventional histopathology and immunostaining for infiltrating M2 macrophages. Moreover, human macrophages derived from monocytes (MDM) or THP-1 cells (THP-derived macrophages [TDM]) were seeded onto dEACcon and dEACintens, and activation was assessed either by cytokine expression or matrix metalloprotease 2 and 7 staining. dEACintens showed a significantly reduced inflammatory infiltration (52%; p < 0.0001), as well as an earlier and denser neovascularization (1.4-fold, p < 0.0001) independent of CCN1 coating, which, however, reduced fibrosis exclusively with dEACintens (26-53%; p < 0.05). Human MDM seeded for 48 h onto dEACintens showed higher transcript levels for anti-inflammatory IL-10 (2.3-fold), proinflammatory TNFα (2.2-fold), and macrophage/monocyte recruiting MIP1α (3.5-fold; all p < 0.05) and MCP (2.7-fold; p < 0.01), whereas 1.92-fold more TDM on dEACintens showed staining for MMP2 (p > 0.001). Thus, although being advantageous in regard to fibrosis, CCN1 coating of dEACintens does not appear to be necessary for further improving dEACintens excellent biocompatibility in rats. In humans, the unspecific cellular immune response toward dEACintens seemed to be more complex, but generally comparable to the mild acute inflammatory tissue reaction with high remodeling activity as observed after rat subcutaneous implantation.

Low Immunogenic Endothelial Cells Maintain Morphological and Functional Properties Required for Vascular Tissue Engineering.

The limited availability of native vessels suitable for the application as hemodialysis shunts or bypass material demands new strategies in cardiovascular surgery. Tissue-engineered vascular grafts containing autologous cells are considered ideal vessel replacements due to the low risk of rejection. However, endothelial cells (EC), which are central components of natural blood vessels, are difficult to obtain from elderly patients of poor health. Umbilical cord blood represents a promising alternative source for EC, but their allogeneic origin corresponds with the risk of rejection after allotransplantation. To reduce this risk, the human leukocyte antigen class I (HLA I) complex was stably silenced by lentiviral vector-mediated RNA interference (RNAi) in EC from peripheral blood and umbilical cord blood and vein. EC from all three sources were transduced by 93.1% ± 4.8% and effectively, HLA I-silenced by up to 67% compared to nontransduced (NT) cells or transduced with a nonspecific short hairpin RNA, respectively. Silenced EC remained capable to express characteristic endothelial surface markers such as CD31 and vascular endothelial cadherin important for constructing a tight barrier, as well as von Willebrand factor and endothelial nitric oxide synthase important for blood coagulation and vessel tone regulation. Moreover, HLA I-silenced EC were still able to align under unidirectional flow, to take up acetylated low-density lipoprotein, and to form capillary-like tube structures in three-dimensional fibrin gels similar to NT cells. In particular, addition of adipose tissue-derived mesenchymal stem cells significantly improved tube formation capability of HLA I-silenced EC toward long and widely branched vascular networks necessary for prevascularizing vascular grafts. Thus, silencing HLA I by RNAi represents a promising technique to reduce the immunogenic potential of EC from three different sources without interfering with EC-specific morphological and functional properties required for vascular tissue engineering. This extends the spectrum of available cell sources from autologous to allogeneic sources, thereby accelerating the generation of tissue-engineered vascular grafts in acute clinical cases.

Safety of Simultaneous Coronary Artery Bypass Grafting and Carotid Endarterectomy Versus Isolated Coronary Artery Bypass Grafting: A Randomized Clinical Trial.

BACKGROUND AND PURPOSE: The optimal operative strategy in patients with severe carotid artery disease undergoing coronary artery bypass grafting (CABG) is unknown. We sought to investigate the safety and efficacy of synchronous combined carotid endarterectomy and CABG as compared with isolated CABG. METHODS: Patients with asymptomatic high-grade carotid artery stenosis ≥80% according to ECST (European Carotid Surgery Trial) ultrasound criteria (corresponding to ≥70% NASCET [North American Symptomatic Carotid Endarterectomy Trial]) who required CABG surgery were randomly assigned to synchronous carotid endarterectomy+CABG or isolated CABG. To avoid unbalanced prognostic factor distributions, randomization was stratified by center, age, sex, and modified Rankin Scale. The primary composite end point was the rate of stroke or death at 30 days. RESULTS: From 2010 to 2014, a total of 129 patients were enrolled at 17 centers in Germany and the Czech Republic. Because of withdrawal of funding after insufficient recruitment, enrolment was terminated early. At 30 days, the rate of any stroke or death in the intention-to-treat population was 12/65 (18.5%) in patients receiving synchronous carotid endarterectomy+CABG as compared with 6/62 (9.7%) in patients receiving isolated CABG (absolute risk reduction, 8.8%; 95% confidence interval, -3.2% to 20.8%; PWALD=0.12). Also for all secondary end points at 30 days and 1 year, there was no evidence for a significant treatment-group effect although patients undergoing isolated CABG tended to have better outcomes. CONCLUSIONS: Although our results cannot rule out a treatment-group effect because of lack of power, a superiority of the synchronous combined carotid endarterectomy+CABG approach seems unlikely. Five-year follow-up of patients is still ongoing. CLINICAL TRIAL REGISTRATION: URL: https://www.controlled-trials.com. Unique identifier: ISRCTN13486906.

Is the frozen elephant trunk procedure superior to the conventional elephant trunk procedure for completion of the second stage?

OBJECTIVES: Our goal was to compare the results and outcomes of second-stage completion in patients who had previously undergone the elephant trunk (ET) or the frozen elephant trunk (FET) procedure for the treatment of complex aortic arch and descending aortic disease. METHODS: Between August 2001 and December 2014, 53 patients [mean age 61 ± 13 years, 64% (n = 34) male] underwent a second-stage completion procedure. Of these patients, 32% (n = 17) had a previous ET procedure and 68% (n = 36) a previous FET procedure as a first-stage procedure. RESULTS: The median times to the second-stage procedure were 7 (0-78) months in the ET group and 8 (0-66) months in the FET group. The second-stage procedure included thoracic endovascular aortic repair in 53% (n = 28) of patients and open surgical repair in 47% (n = 25). More endovascular interventions were performed in FET patients (61%, n = 22) than in the ET group (35%, n = 6, P = 0.117). The in-hospital mortality rate was significantly lower in the FET (8%, n = 3) group compared with the ET group (29%, n = 5, P = 0.045). The median follow-up time after the second-stage operation for the entire cohort was 4.6 (0.4-10.4) years. The 5-year survival rate was 76% in the ET patients versus 89% in the FET patients (log-rank: P = 0.11). CONCLUSIONS: We observed a significantly lower in-hospital mortality rate in the FET group compared to the ET group. This result might be explained by the higher rate of endovascular completion in the FET group. We assume that the FET procedure offers the benefit of a more ideal landing zone, thus facilitating endovascular completion.

Renal function interferes with copeptin in prediction of major adverse cardiac events in patients undergoing vascular surgery.

OBJECTIVE: Precise perioperative risk stratification is important in vascular surgery patients who are at high risk for major adverse cardiovascular events (MACE) peri- and postoperatively. In clinical practice, the patient's perioperative risk is predicted by various indicators, e.g. revised cardiac index (RCRI) or modifications thereof. Patients suffering from chronic kidney disease (CKD) are stratified into a higher risk category. We hypothesized that Copeptin as a novel biomarker for hemodynamic stress could help to improve the prediction of perioperative cardiovascular events in patients undergoing vascular surgery including patients with chronic kidney disease. METHODS: 477 consecutive patients undergoing abdominal aortic, peripheral arterial or carotid surgery from June 2007 to October 2012 were prospectively enrolled. Primary endpoint was 30-day postoperative major adverse cardiovascular events (MACE). RESULTS: 41 patients reached the primary endpoint, including 63.4% aortic, 26.8% carotid, and 9.8% peripheral surgeries. Linear regression analysis showed that RCRI (P< .001), pre- (P< .001), postoperative Copeptin (P< .001) and Copeptin level change (P= .001) were associated with perioperative MACE, but CKD remained independently associated with MACE and Copeptin levels. Multivariate regression showed that increased Copeptin levels added risk predictive information to the RCRI (P= .003). Especially in the intermediate RCRI categories was Copeptin significantly associated with the occurrence of MACE. (P< .05 Kruskal Wallis test). Subdivision of the study cohort into CKD stages revealed that preoperative Copeptin was significantly associated with CKD stages (P< .0001) and preoperative Copeptin measurements could not predict MACE in patients with more severe CKD stages. CONCLUSION: Preoperative Copeptin loses its risk predictive potential for perioperative MACE in patients with chronic kidney disease undergoing vascular surgery.

Thoracic endovascular aortic repair after iatrogenic aortic dissection and false lumen stent grafting.

Iatrogenic aortic dissections are a severe complication after thoracic endovascular aortic repair, and treatment guidelines do not exist. Herein, we report a patient who experienced an iatrogenic type B aortic dissection during elective thoracic endovascular aortic repair and suggest an interventional treatment option.

Coating decellularized equine carotid arteries with CCN1 improves cellular repopulation, local biocompatibility, and immune response in sheep.

Decellularized equine carotid arteries (dEAC) are potential alternatives to alloplastic vascular grafts although there are certain limitations in biocompatibility and immunogenicity. Here, dEAC were coated with the matricellular protein CCN1 and evaluated in vitro for its cytotoxic and angiogenic effects and in vivo for cellular repopulation, local biocompatibility, neovascularization, and immunogenicity in a sheep model. CCN1 coating resulted in nontoxic matrices not compromising viability of L929 fibroblasts and endothelial cells (ECs) assessed by WST-8 assay. Functionality of CCN1 was maintained as it induced typical changes in fibroblast morphology and MMP3 secretion. For in vivo testing, dEAC±CCN1 (n=3 each) and polytetrafluoroethylene (PTFE) protheses serving as controls (n=6) were implanted as cervical arteriovenous shunts. After 14 weeks, grafts were harvested and evaluated immunohistologically. PTFE grafts showed a patency rate of only 33% and lacked cellular repopulation. Both groups of bioartificial grafts were completely patent and repopulated with ECs and smooth muscle cells (SMCs). However, whereas dEAC contained only patch-like aggregates of SMCs and a partial luminal lining with ECs, CCN1-coated grafts showed multiple layers of SMCs and a complete endothelialization. Likewise, CCN1 coating reduced leukocyte infiltration and fibrosis and supported neovascularization. In addition, in a three-dimensional assay, CCN1 coating increased vascular tube formation in apposition to the matrix 1.6-fold. Graft-specific serum antibodies were increased by CCN1 up to 6 weeks after implantation (0.89±0.03 vs. 1.08±0.04), but were significantly reduced after 14 weeks (0.85±0.04 vs. 0.69±0.02). Likewise, restimulated lymphocyte proliferation was significantly lower after 14 weeks (1.78±0.09 vs. 1.32±0.09-fold of unstimulated). Thus, CCN1 coating of biological scaffolds improves local biocompatibility and accelerates scaffold remodeling by enhancing cellular repopulation and immunologic tolerance, making it a promising tool for generation of bioartificial vascular prostheses.

Aortic valve replacement via right anterolateral thoracotomy in the case of a patient with extreme mediastinal right-shift following pneumonectomy.

We report on the case of a 68-year-old male patient with the history of right pneumonectomy due to bronchial carcinoma, who was referred for aortic valve replacement due to severe calcified aortic stenosis. Pre-operative chest X-ray and computed tomography (CT) revealed an unusually pronounced mediastinal shift to the right. Despite this unusual anatomy, we decided to perform surgery using the right anterolateral thoracotomy following thorough pre-operative planning using 3D-volume rendering of the CT data-set. This approach yielded excellent exposure of the aortic root and the ascending aorta, respectively. Following an uneventful operative and post-operative course the patient could be discharged on post-OP day 6.Although only occasionally described for aortic valve replacement a right anterolateral thoracotomy may represent a valuable surgical approach, particular in patients with unusual anatomy, e.g. a mediastinal right-shift. However, thorough pre-operative planning, i.e. using visualization and planning techniques such as 3D-volume rendering should be mandatory as it provides information crucial to facilitate surgical steps and thus, may help avoid severe surgical complications.

Unusual Case of an Arterial Thoracic Outlet Syndrome due to Srb Anomaly.

A thoracic outlet syndrome (TOS) is caused by arterial or nervous obstruction because of skeletal or muscular anomalies and hypertrophies. Congenital rib anomalies occur with low incidences (0.15-0.31%), predominantly affect the right side and are normally diagnosed at a young age or remain asymptomatic throughout life. Here, we report on the unusual case of a 71-year-old female patient with subacute ischemia of the left arm due to a TOS resulting from Srb anomaly, a very rare congenital rib anomaly.

Laser printing of three-dimensional multicellular arrays for studies of cell-cell and cell-environment interactions.

Utilization of living cells for therapies in regenerative medicine requires a fundamental understanding of the interactions between different cells and their environment. Moreover, common models based on adherent two-dimensional cultures are not appropriate to simulate the complex interactions that occur in a three-dimensional (3D) cell-microenvironment in vivo. In this study, we present a computer-aided method for the printing of multiple cell types in a 3D array using laser-assisted bioprinting. By printing spots of human adipose-derived stem cells (ASCs) and endothelial colony-forming cells (ECFCs), we demonstrate that (i) these cell spots can be arranged layer-by-layer in a 3D array; (ii) any cell-cell ratio, cell quantity, cell-type combination, and spot spacing can be realized within this array; and (iii) the height of the 3D array is freely scalable. As a proof of concept, we printed separate spots of ASCs and ECFCs within a 3D array and observed cell-cell interactions in vascular endothelial growth factor-free medium. It has been demonstrated that direct cell-cell contacts trigger the development of stable vascular-like networks. This method can be applied to study complex and dynamic relationships between cells and their local environment.

Cryopreserved arterial homografts vs silver-coated Dacron grafts for abdominal aortic infections with intraoperative evidence of microorganisms.

OBJECTIVE: The gold standard for the treatment of abdominal aortic infections remains controversial. Cryopreserved arterial homografts and silver-coated Dacron grafts have both been advocated as reasonable grafts. Direct clinical or experimental comparisons between these two treatment options have not been published before. This study compared cryopreserved arterial homografts and silver-coated Dacron grafts for the treatment of abdominal aortic infections in a contaminated intraoperative field. METHODS: From January 2004 to December 2009, 56 patients underwent in situ arterial reconstruction for an abdominal aortic infection. Patients with negative intraoperative microbiologic specimens were excluded. We compared 22 of 36 patients (61%) receiving cryopreserved arterial homografts (group A) vs 11 of 20 (55%) receiving a silver-coated Dacron graft (group B). Primary outcomes were survival and limb salvage; secondary outcomes were graft patency and reinfection. Direct costs of therapy were also calculated. RESULTS: Thirty-day mortality was 14% in group A and 18% in group B (P >.99), and 2-year survival rates were 82% and 73%, respectively (P = .79). After 2 years, limb salvage was 96% and 100%, respectively (P = .50), whereas graft patency was 100% for both groups. Major complications were an aneurysmal degeneration in group A and graft reinfection in group B (n = 2). Median direct costs of therapy (in US $) were $41,697 (range, $28,347-$53,362) in group A and $15,531 (range, $11,310-$22,209) in group B (P = .02). CONCLUSIONS: Our results show comparable effectiveness between cryopreserved arterial homograft and silver-coated Dacron graft in the contaminated operative field with respect to early mortality and midterm survival. Graft-inherent complications, aneurysmal degeneration for homografts, and reinfection for silver graft, were also observed. The in situ arterial reconstruction with homografts is nearly three times more expensive than with silver graft.