External Support of Autologous Internal Jugular Vein Grafts with FRAME Mesh in a Porcine Carotid Artery Model.

BACKGROUND: Autologous vein grafts are widely used for bypass procedures in cardiovascular surgery. However, these grafts are susceptible to failure due to vein graft disease. Our study aimed to evaluate the impact of the latest-generation FRAME external support on vein graft remodeling in a preclinical model. METHODS: We performed autologous internal jugular vein interposition grafting in porcine carotid arteries for one month. Four grafts were supported with a FRAME mesh, while seven unsupported grafts served as controls. The conduits were examined through flowmetry, angiography, macroscopy, and microscopy. RESULTS: The one-month patency rate of FRAME-supported grafts was 100% (4/4), whereas that of unsupported controls was 43% (3/7, Log-rank p = 0.071). On explant angiography, FRAME grafts exhibited significantly more areas with no or mild stenosis (9/12) compared to control grafts (3/21, p = 0.0009). Blood flow at explantation was higher in the FRAME grafts (145 ± 51 mL/min) than in the controls (46 ± 85 mL/min, p = 0.066). Area and thickness of neo-intimal hyperplasia (NIH) at proximal anastomoses were similar for the FRAME and the control groups: 5.79 ± 1.38 versus 6.94 ± 1.10 mm2, respectively (p = 0.558) and 480 ± 95 vs. 587 ± 52 µm2/µm, respectively (p = 0.401). However, in the midgraft portions, the NIH area and thickness were significantly lower in the FRAME group than in the control group: 3.73 ± 0.64 vs. 6.27 ± 0.64 mm2, respectively (p = 0.022) and 258 ± 49 vs. 518 ± 36 µm2/µm, respectively (p = 0.0002). CONCLUSIONS: In our porcine model, the external mesh FRAME improved the patency of vein-to-carotid artery grafts and protected them from stenosis, particularly in the mid regions. The midgraft neo-intimal hyperplasia was two-fold thinner in the meshed grafts than in the controls.

Interposition of right internal iliac artery free-graft for left coronary artery reimplantation in adults with anomalous left coronary artery originating from the pulmonary artery: case series and long-term results.

Anomalous left coronary artery originating from the pulmonary artery (ALCAPA) is an infrequent congenital anomaly. Presentation of this syndrome is rare in adults. Nevertheless, adult patients are at risk of ischaemia, arrhythmias or sudden cardiac death and always require surgical intervention. At our institution, a specific technique of interposition of the right internal iliac artery as a free-graft for left coronary artery reimplantation was used in adult ALCAPA patients. The aim of this report is to determine long-term results and experiences with this surgical technique.

Vascular Remodeling of Clinically Used Patches and Decellularized Pericardial Matrices Recellularized with Autologous or Allogeneic Cells in a Porcine Carotid Artery Model.

Background: Cardiovascular surgery is confronted by a lack of suitable materials for patch repair. Acellular animal tissues serve as an abundant source of promising biomaterials. The aim of our study was to explore the bio-integration of decellularized or recellularized pericardial matrices in vivo. Methods: Porcine (allograft) and ovine (heterograft, xenograft) pericardia were decellularized using 1% sodium dodecyl sulfate ((1) Allo-decel and (2) Xeno-decel). We used two cell types for pressure-stimulated recellularization in a bioreactor: autologous adipose tissue-derived stromal cells (ASCs) isolated from subcutaneous fat of pigs ((3) Allo-ASC and (4) Xeno-ASC) and allogeneic Wharton's jelly mesenchymal stem cells (WJCs) ((5) Allo-WJC and (6) Xeno-WJC). These six experimental patches were implanted in porcine carotid arteries for one month. For comparison, we also implanted six types of control patches, namely, arterial or venous autografts, expanded polytetrafluoroethylene (ePTFE Propaten® Gore®), polyethylene terephthalate (PET Vascutek®), chemically stabilized bovine pericardium (XenoSure®), and detoxified porcine pericardium (BioIntegral® NoReact®). The grafts were evaluated through the use of flowmetry, angiography, and histological examination. Results: All grafts were well-integrated and patent with no signs of thrombosis, stenosis, or aneurysm. A histological analysis revealed that the arterial autograft resembled a native artery. All other control and experimental patches developed neo-adventitial inflammation (NAI) and neo-intimal hyperplasia (NIH), and the endothelial lining was present. NAI and NIH were most prominent on XenoSure® and Xeno-decel and least prominent on NoReact®. In xenografts, the degree of NIH developed in the following order: Xeno-decel > Xeno-ASC > Xeno-WJC. NAI and patch resorption increased in Allo-ASC and Xeno-ASC and decreased in Allo-WJC and Xeno-WJC. Conclusions: In our setting, pre-implant seeding with ASC or WJC had a modest impact on vascular patch remodeling. However, ASC increased the neo-adventitial inflammatory reaction and patch resorption, suggesting accelerated remodeling. WJC mitigated this response, as well as neo-intimal hyperplasia on xenografts, suggesting immunomodulatory properties.

Accelerated in vitro recellularization of decellularized porcine pericardium for cardiovascular grafts.

An ideal decellularized allogenic or xenogeneic cardiovascular graft should be capable of preventing thrombus formation after implantation. The antithrombogenicity of the graft is ensured by a confluent endothelial cell layer formed on its surface. Later repopulation and remodeling of the scaffold by the patient's cells should result in the formation of living autologous tissue. In the work presented here, decellularized porcine pericardium scaffolds were modified by growing a fibrin mesh on the surface and inside the scaffolds, and by attaching heparin and human vascular endothelial growth factor (VEGF) to this mesh. Then the scaffolds were seeded with human adipose tissue-derived stem cells (ASCs). While the ASCs grew only on the surface of the decellularized pericardium, the fibrin-modified scaffolds were entirely repopulated in 28 d, and the scaffolds modified with fibrin, heparin and VEGF were already repopulated within 6 d. Label free mass spectrometry revealed fibronectin, collagens, and other extracellular matrix proteins produced by ASCs during recellularization. Thin layers of human umbilical endothelial cells were formed within 4 d after the cells were seeded on the surfaces of the scaffold, which had previously been seeded with ASCs. The results indicate that an artificial tissue prepared by in vitro recellularization and remodeling of decellularized non-autologous pericardium with autologous ASCs seems to be a promising candidate for cardiovascular grafts capable of accelerating in situ endothelialization. ASCs resemble the valve interstitial cells present in heart valves. An advantage of this approach is that ASCs can easily be collected from the patient by liposuction.

Post-infarction left ventricular free wall rupture: 12-years experience from the Cardiac Centre of the Institute of Clinical and Experimental Medicine in Prague, Czech Republic.

BACKGROUND: Post-infarction left ventricular free wall rupture (LVFWR) is a feared and catastrophic complication of myocardial infarction that carries a high surgical and hospital mortality. Due to the rarity of this complication, little information exists on surgical treatment and outcomes. Goal and Methods. The goal of this study was to present our experience with LVFWR. We present a retrospective cohort of 19 consecutive patients who were surgically treated in the Cardiac Centre of the Institute of Clinical and Experimental Medicine in Prague between January 2006 and December 2017. RESULTS: Thirty-day mortality was 26%. Five patients died. Four patients died in the operating theatre and one patient on the ninth postoperative day following re-rupture. Seventy-four percent of the patient cohort survived and were discharged from hospital. The median length of follow-up was 45 months (range 0.75-150). No patient died during follow-up. Median postoperative ejection fraction was 45% (range 25-65%). Angina pectoris and dyspnea were investigated during follow-up and graded according to the Canadian cardiology society (CCS) and the New York Heart Association (NYHA) classifications. Fourteen patients had CCS class I, eight patients had NYHA class I dyspnea and six patients had NYHA class II. Re-rupture occurred after hospital discharge in one patient one month after the original surgery. The patient was treated successfully by urgent surgical intervention. CONCLUSION: LVFWR is a catastrophic and challenging complication of myocardial infarction. Good outcomes can be achieved by rapid diagnosis and urgent surgical intervention as shown by our results.

The Effect of Different Thawing Rates on Cryopreserved Human Iliac Arteries Allograft's Structural Damage and Mechanical Properties.

INTRODUCTION: The rate of thawing of cryopreserved human iliac arteries allografts (CHIAA) directly affects the severeness of structural changes that occur during this process. METHOD: The experiment was performed on ten CHIAA. The 10% dimethylsulphoxide in 6% hydroxyethyl starch solution was used as the cryoprotectant; all CHIAA were cooled at a controlled rate and stored in the vapor phase of liquid nitrogen (-194°C). Two thawing protocols were tested: (1) placing the CHIAA in a water bath at 37°C, and (2) the CHIAA were thawed in a controlled environment at 5°C. All samples underwent analysis under a scanning electron microscope. Testing of the mechanical properties of the CHIAA was evaluated on a custom-built single axis strain testing machine. Longitudinal and circumferential samples were prepared from each tested CHIAA. RESULTS: Ultrastructural analysis revealed that all five CHIAA thawed during the thawing protocol 1 which showed significantly more damage to the subendothelial structures when compared to the samples thawed in protocol 2. Mechanical properties: Thawing protocol 1-longitudinal UTS 2, 53 ± 0, 47 MPa at relative strain 1, 27 ± 0, 12 and circumferential UTS 1, 94 ± 0, 27 MPa at relative strain 1, 33 ± 0, 09. Thawing protocol 2-longitudinal ultimate tensile strain (UTS) 2, 42 ± 0, 34 MPa at relative strain 1, 32 ± 0, 09 and circumferential UTS 1, 98 ± 0, 26 MPa at relative strain 1, 29 ± 0, 07. Comparing UTS showed no statistical difference between thawing methods. CONCLUSION: Despite the significant differences in structural changes of presented thawing protocols, the ultimate tensile strain showed no statistical difference between thawing methods.

Serum albumin in patients undergoing transcatheter aortic valve replacement: A meta-analysis.

Transcatheter aortic valve replacement is becoming a more common therapeutic option for the treatment of aortic stenosis in patients at high risk for invasive surgery, but detecting which patients will benefit clinically can be challenging. Hypoalbuminemia is a useful prognostic marker for chronic inflammation in this population. We carried out a systematic review and meta-analysis of studies evaluating the prognostic value of serum albumin level in patients undergoing transcatheter aortic valve replacement. A literature search of PubMed, Embase, ScienceDirect, Web of Science, SciELO, BIOSIS, Wanfang, and CNKI databases was conducted. Articles published between January 2000 and December 2017 reporting on the prognostic value of low levels of serum albumin in patients undergoing transcatheter aortic valve replacement were analyzed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. 11 studies including 6456 patients met inclusion criteria for meta-analysis. A lower serum albumin level was associated with a lower survival rate at follow-up in patients who underwent transcatheter aortic valve replacement. A sub-group analysis of eight studies reporting adjusted hazard ratios indicated that low serum albumin was independently correlated with increased post-operative mortality. The hazard ratio of mortality risk associated with each 1 g/dL increment in serum albumin level was 0.46, suggesting a potential dose-response relationship between increased serum albumin level and increased survival rate in patients undergoing transcatheter aortic valve replacement. This meta-analysis provides strong evidence for the utility of serum albumin as a prognostic marker in aortic stenosis patients undergoing transcatheter aortic valve replacement, with low serum albumin levels (2.5-3.5 g/dL) suggesting poor prognosis.

Geometric Ring Annuloplasty for Aortic Valve Repair During Aortic Aneurysm Surgery: Two-Year Clinical Trial Results.

OBJECTIVE: An aortic annuloplasty ring could be useful for aortic valve repair. This trial evaluated intermediate-term outcomes of internal geometric ring annuloplasty for repair of trileaflet and bicuspid aortic insufficiency associated with ascending aortic and/or aortic root aneurysms. METHODS: Under regulatory supervision, 47 patients with aortic insufficiency and ascending aortic (n = 22) and/or aortic root (n = 25) aneurysms were managed with aortic valve repair and aneurysm resection. Valve repair was performed using trileaflet (n = 40) or bicuspid (n = 7) internal geometric rings, together with leaflet reconstruction. Ascending aortic and/or remodeling root replacements were accomplished with Dacron grafts 5 to 7 mm larger than the rings. An Echo Core Lab provided independent echocardiographic assessments, and changes over time were evaluated by Friedman tests. RESULTS: Mean ± SD age was 60 ± 14 years, 57% (27/47) were male, 15% (7/47) had bicuspid valves, 87% (41/47) had moderate-to-severe aortic insufficiency, and 13% (6/47) had mild aortic insufficiency. All patients had annular dilatation, with a mean ± SD of 26.5 ± 2.6 mm before repair, and mean ± SD ring sizes were 21.7 ± 1.7 mm. Follow-up was 42 months (mean = 27 months). No operative mortality or valve-related complications occurred. Two patients died beyond 1 year from nonvalve-related causes. One patient required valve replacement for repair failure. Survival free of complications or valve replacement was 94% at 2 years. Significant reduction in aortic insufficiency and New York Heart Association class were observed (P < 0.0001), and valve gradients remained low. No heart block or direct ring complications occurred. CONCLUSIONS: In preliminary regulatory studies, aortic ring annuloplasty seemed safe and effective during aortic aneurysm surgery. This approach could help standardize aortic valve repair.

Vasa vasorum of the failed aorto-coronary venous grafts.

PURPOSE: This study was designed to investigate the distribution of vasa vasorum in walls of failed aorto-coronary venous grafts. METHODS: Fifty-one diseased venous grafts harvested from 39 patients underwent qualitative histological evaluation. The morphology of the grade of the pathological changes and the extent of the vascularisation were examined, and related to the length of the interval between the primary surgery and the explantation. The obtained results were placed into five groups, substantially differing one from the other in morphology and vascularisation. RESULTS: The intervals between grafts implantation and explantation ranged from 1 day to 35 years. The onset of arterialization of the graft media was observed on average at 1 month after bypass implantation. During this same time period massive intimal hyperplasia and atherosclerosis occurred. Vasa vasorum proliferation from the adventitia to the outer layers of the media was first apparent between 7 and 24 months after implantation. Proliferation of the vasa vasorum throughout the entire atherosclerotic media and hyperplastic intima continued for a much longer time interval. CONCLUSION: No correlation between neoangiogenesis and age, sex or type of bypassed coronary branch was proven. Regarding the given findings, the authors believe that changes in hemodynamic conditions and endothelial trauma are primarily responsible for the development of graft disease and that vasa vasorum proliferation is only a secondary reaction to the structural changes of the graft wall. To what extent the frequently present pre-existing intimal hyperplasia of venous bypass grafts play in the development of graft disease remains questionable.

Isovolumic loading of the failing heart by intraventricular placement of a spring expander attenuates cardiac atrophy after heterotopic heart transplantation.

Cardiac atrophy is the most common complication of prolonged application of the left ventricle (LV) assist device (LVAD) in patients with advanced heart failure (HF). Our aim was to evaluate the course of unloading-induced cardiac atrophy in rats with failing hearts, and to examine if increased isovolumic loading obtained by intraventricular implantation of an especially designed spring expander would attenuate this process. Heterotopic abdominal heart transplantation (HTx) was used as a rat model of heart unloading. HF was induced by volume overload achieved by creation of the aorto-caval fistula (ACF). The degree of cardiac atrophy was assessed as the weight ratio of the heterotopically transplanted heart (HW) to the control heart. Isovolumic loading was increased by intraventricular implantation of a stainless steel three-branch spring expander. The course of cardiac atrophy was evaluated on days 7, 14, 21, and 28 after HTx Seven days unloading by HTx in failing hearts sufficed to substantially decrease the HW (-59 ± 3%), the decrease progressed when measured on days 14, 21, and 28 after HTx Implantation of the spring expander significantly reduced the decreases in whole HW at all the time points (-39 ± 3 compared with -59 ± 3, -52 ± 2 compared with -69 ± 3, -51 ± 2 compared with -71 ± 2, and -44 ± 2 compared with -71 ± 3%, respectively; P<0.05 in each case). We conclude that the enhanced isovolumic heart loading obtained by implantation of the spring expander attenuates the development of unloading-induced cardiac atrophy in the failing rat heart.

A human pericardium biopolymeric scaffold for autologous heart valve tissue engineering: cellular and extracellular matrix structure and biomechanical properties in comparison with a normal aortic heart valve.

The objective of our study was to compare the cellular and extracellular matrix (ECM) structure and the biomechanical properties of human pericardium (HP) with the normal human aortic heart valve (NAV). HP tissues (from 12 patients) and NAV samples (from 5 patients) were harvested during heart surgery. The main cells in HP were pericardial interstitial cells, which are fibroblast-like cells of mesenchymal origin similar to the valvular interstitial cells in NAV tissue. The ECM of HP had a statistically significantly (p < 0.001) higher collagen I content, a lower collagen III and elastin content, and a similar glycosaminoglycans (GAGs) content, in comparison with the NAV, as measured by ECM integrated density. However, the relative thickness of the main load-bearing structures of the two tissues, the dense part of fibrous HP (49 ± 2%) and the lamina fibrosa of NAV (47 ± 4%), was similar. In both tissues, the secant elastic modulus (Es) was significantly lower in the transversal direction (p < 0.05) than in the longitudinal direction. This proved that both tissues were anisotropic. No statistically significant differences in UTS (ultimate tensile strength) values and in calculated bending stiffness values in the longitudinal or transversal direction were found between HP and NAV. Our study confirms that HP has an advantageous ECM biopolymeric structure and has the biomechanical properties required for a tissue from which an autologous heart valve replacement may be constructed.

A Complex Heart Team's Approach to a Patient With Giant Cell Myocarditis.

Giant cell myocarditis is known as a rare and frequently fatal type of myocarditis that is usually characterized by progressive congestive heart failure and frequent ventricular arrhythmias. We report a rare case of giant cell myocarditis in a 64-year-old previously healthy woman. The case was complicated by the rapid development of progressive acute heart failure, which required the comprehensive care of our heart team. Using a broad spectrum of therapeutic approaches, the patient successfully underwent heart transplantation.

Valve interstitial cell culture: Production of mature type I collagen and precise detection.

Collagen often acts as an extracellular and intracellular marker for in vitro experiments, and its quality defines tissue constructs. To validate collagen detection techniques, cardiac valve interstitial cells were isolated from pigs and cultured under two different conditions; with and without ascorbic acid. The culture with ascorbic acid reached higher cell growth and collagen deposition, although the expression levels of collagen gene stayed similar to the culture without ascorbic acid. The fluorescent microscopy was positive for collagen fibers in both the cultures. Visualization of only extracellular collagen returned a higher correlation coefficient when comparing the immunolabeling and second harmonic generation microscopy images in the culture with ascorbic acid. Lastly, it was proved that the hydroxyproline strongly contributes to the second-order susceptibility tensor of collagen molecules, and therefore the second harmonic generation signal is impaired in the culture without ascorbic acid.

Analysis of immune cell populations in atrial myocardium of patients with atrial fibrillation or sinus rhythm.

BACKGROUND: Atrial fibrillation (AF) is the most common arrhythmia and despite obvious clinical importance remains its pathogenesis only partially explained. A relation between inflammation and AF has been suggested by findings of increased inflammatory markers in AF patients. OBJECTIVE: The goal of this study was to characterize morphologically and functionally CD45-positive inflammatory cell populations in atrial myocardium of patients with AF as compared to sinus rhythm (SR). METHODS: We examined 46 subjects (19 with AF, and 27 in SR) undergoing coronary bypass or valve surgery. Peroperative bioptic samples of the left and the right atrial tissue were examined using immunohistochemistry. RESULTS: The number of CD3+ T-lymphocytes and CD68-KP1+ cells were elevated in the left atrial myocardium of patients with AF compared to those in SR. Immune cell infiltration of LA was related to the rhythm, but not to age, body size, LA size, mitral regurgitation grade, type of surgery, systemic markers of inflammation or presence of diabetes or hypertension. Most of CD68-KP1+ cells corresponded to dendritic cell population based on their morphology and immunoreactivity for DC-SIGN. The numbers of mast cells and CD20+ B-lymphocytes did not differ between AF and SR patients. No foci of inflammation were detected in any sample. CONCLUSIONS: An immunohistochemical analysis of samples from patients undergoing open heart surgery showed moderate and site-specific increase of inflammatory cells in the atrial myocardium of patients with AF compared to those in SR, with prevailing population of monocyte-macrophage lineage. These cells and their cytokine products may play a role in atrial remodeling and AF persistence.

Procalcitonin Dynamics After Long-Term Ventricular Assist Device Implantation.

BACKGROUND: Infectious complications (IC) are one of the main causes of worsening prognosis after long-term ventricular assist device (LVAD) implantation. Procalcitonin (PCT) is widely used for diagnosis of a bacterial infection. The objective of this study was to assess PCT dynamics after LVAD surgery and their relationship to the infectious complications. METHODS: A total of 25 consecutive patients indicated for LVAD implantation as a bridge to heart transplant were included. Procalcitonin levels were prospectively assessed before surgery and during the postoperative period (day 1, 2, 14 and 30). Values were compared according to the presence of IC. RESULTS: Procalcitonin levels were low before surgery, raised significantly within 1st and 2nd day after operation and decreased in the 14th and 30th days back to the baseline. There was no significant difference in PCT values between patients with or without IC as well as with or without right ventricle assist device (RVAD). Acute renal failure (ARF) increased PCT significantly only 14 days after LVAD implantation. In patients with ARF and/or RVAD we observed significantly higher PCT values in the 2nd, 14th and 30th day after operation. In subjects with IC and/or ARF and/or RVAD we also observed significantly elevated PCT concentrations 2 and 14 days after surgery. CONCLUSIONS: Our data show that the ability of PCT to detect IC in patients after LVAD implantation is limited and its concentrations more likely correlate with postoperative complications in general.

Myocardial iron content and mitochondrial function in human heart failure: a direct tissue analysis.

AIMS: Iron replacement improves clinical status in iron-deficient patients with heart failure (HF), but the pathophysiology is poorly understood. Iron is essential not only for erythropoiesis, but also for cellular bioenergetics. The impact of myocardial iron deficiency (MID) on mitochondrial function, measured directly in the failing human heart, is unknown. METHODS AND RESULTS: Left ventricular samples were obtained from 91 consecutive HF patients undergoing transplantation and 38 HF-free organ donors (controls). Total myocardial iron content, mitochondrial respiration, citric acid cycle and respiratory chain enzyme activities, respiratory chain components (complex I-V), and protein content of reactive oxygen species (ROS)-protective enzymes were measured in tissue homogenates to quantify mitochondrial function. Myocardial iron content was lower in HF compared with controls (156 ± 41 vs. 200 ± 38 µg·g-1 dry weight, P < 0.001), independently of anaemia. MID (the lowest iron tercile in HF) was associated with more extensive coronary disease and less beta-blocker usage compared with non-MID HF patients. Compared with controls, HF patients displayed reduced myocardial oxygen2 respiration and reduced activity of all examined mitochondrial enzymes (all P < 0.001). MID in HF was associated with preserved activity of respiratory chain enzymes but reduced activity of aconitase and citrate synthase (by -26% and -15%, P < 0.05) and reduced expression of catalase, glutathione peroxidase, and superoxide dismutase 2. CONCLUSION: Myocardial iron content is decreased and mitochondrial functions are impaired in advanced HF. MID in HF is associated with diminished citric acid cycle enzyme activities and decreased ROS-protecting enzymes. MID may contribute to altered myocardial substrate use and to worsening of mitochondrial dysfunction that exists in HF.

Personalized external aortic root support: a review of the current status.

Personalized external aortic root support (PEARS) is an emerging technology. It is a pre-emptive operation to halt aortic root expansion and maintain aortic valve function in Marfan syndrome and is also applicable to aortic root aneurysms of other aetiologies. To fully evaluate PEARS, awareness of all those who advise these patients is necessary to ensure that patients are fully informed of the alternative operations, to carefully build experience, to ensure safety and quality and to monitor outcomes. Herein, we present a summary of published methods and outcomes and the arrangements in place for fuller evaluation.