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Aims Recipients of left ventricular assist devices (LVAD) are exposed to increased risk of adverse clinical events. One of the potential contributing factors is non‐pulsatile flow generated by LVAD. We evaluated the association of flow patterns in carotid arteries and of increased arterial stiffness with death and cerebrovascular events in LVAD recipients. Methods and results We analysed data from 83 patients [mean age 54 ± 15 years; 12 women; HeartMate II (HMII), n = 34; HeartMate 3 (HM3), n = 49]. Pulsatile and resistive indexes, atherosclerotic changes in carotid arteries (measured by duplex ultrasound), and arterial stiffness [measured by Endo‐PAT 2000 as the augmentation index standardized for heart rate (AI@75)] were evaluated 3 and 6 months after LVAD implantation. Sixteen patients died during follow‐up (27.3 months; interquartile range 15.7–44.3). After adjusting for the main variables examined, the pulsatility index measured at 3 months was positively associated with increased hazard ratios (HR) for death and cerebrovascular events [HR 9.8, 95% confidence interval (CI) 1.62–59.42], with HR increasing after adding AI@75 to the model (HR 18.8, 95% CI 2.44–145.50). In HM3 recipients, HR was significantly lower than in HMII recipients (HR 0.31, 95% CI 0.11–0.91), but the significance disappeared after adding AI@75 to the model (HR 0.33, 95% CI 0.09–1.18). Conclusions The risk of death and cerebrovascular events in LVAD recipients is associated with increased pulsatility index in carotid arteries and potentiated by increased arterial stiffness. The same risk is attenuated by HM3 LVAD implantation, but this effect is weakened by increased arterial stiffness.

Introduction: Inherited thrombophilias represent a concerning risk factor due to a proclivity to an aberrant clot formation. However, in patients with left ventricular assist device (LVAD), their impact on bleeding and thrombotic complications remains still poorly understood. The aim of the present study was to evaluate the effect of thrombophilic mutation directed anticoagulation therapy on adverse clinical outcomes in LVAD patients. Materials and methods: About 138 consecutive patients indicated for LVAD implant (HeartMate II, Abbott, Plymouth, USA) were prospectively screened for three major thrombophilic mutations: factor II (prothrombin), factor V Leiden, and homozygous methylenetetrahydrofolate reductase (MTHFR). Subsequently, discordant individualized anticoagulation targets of INR 2.5–3.0 in thrombophilia positive and INR 1.8–2.2 in negative patients were established; notably without anti-platelet agents given the center standard of care. Results: Mean age was 50 ± 12.7 years, 83% male. Mean duration of support was 464.5 days (SD 482.9; SEM 41.1) and median of 310 days (IQR 162; 546). Full thrombophilia positive cohort analysis has not revealed any significant impact on event free survival. In contrast, detailed analysis of specific thrombophilias subsets has revealed Factor II prothrombin mutation as a significant predisposition for the pump thrombosis risk (SHR 10.48; p = 0.001) despite more aggressive prespecified anticoagulation target. Moreover, the incidence of bleeding events in prothrombin group was also significantly increased (SHR 6.0; p = 0.03). Conclusions: Our observations suggest that specific thrombophilias in LVAD patients may pose different intensity predisposition for thrombotic complications. Factor II (prothrombin) positive mutation was identified as significant risk factor associated with the pump thrombosis.

The CARMAT-Total Artificial Heart (C-TAH) is designed to provide heart replacement therapy for patients with end-stage biventricular failure. This report details the reliability and efficacy of the autoregulation device control mechanism (auto-mode), designed to mimic normal physiologic responses to changing patient needs. Hemodynamic data from a continuous cohort of 10 patients implanted with the device, recorded over 1,842 support days in auto-mode, were analyzed with respect to daily changing physiologic needs. The C-TAH uses embedded pressure sensors to regulate the pump output. Right and left ventricular outputs are automatically balanced. The operator sets target values and the inbuilt algorithm adjusts the stroke volume and beat rate, and hence cardiac output, automatically. Auto-mode is set perioperatively after initial postcardiopulmonary bypass hemodynamic stabilization. All patients showed a range of average inflow pressures of between 5 and 20 mm Hg during their daily activities, resulting in cardiac output responses of between 4.3 and 7.3 L/min. Operator adjustments were cumulatively only required on 20 occasions. This report demonstrates that the C-TAH auto-mode effectively produces appropriate physiologic responses reflective of changing patients' daily needs and represents one of the unique characteristics of this device in providing almost physiologic heart replacement therapy.

Implantation of current generation left ventricular assist devices (LVADs) in the treatment of end-stage heart failure (HF), not only improves HF symptoms and end-organ perfusion, but also leads to cellular and molecular responses, presumably in response to the continuous flow generated by these devices. MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression in multiple biological processes, including the pathogenesis of HF. In our study, we examined the influence of long-term LVAD support on changes in flow-sensitive miRNAs in plasma.Blood samples from patients with end-stage heart failure (N = 33; age = 55.7 ± 11.6 years) were collected before LVAD implantation and 3, 6, 9, and 12 months after implantation. Plasma levels of the flow-sensitive miRNAs; miR-10a, miR-10b, miR-146a, miR-146b, miR-663a, miR-663b, miR-21, miR-155, and miR-126 were measured using quantitative PCR.Increasing quantities of miR-126 (P0.03) and miR-146a (P0.02) was observed at each follow-up visit after LVAD implantation. A positive association between miR-155 and Belcaro score (P0.04) and an inverse correlation between miR-126 and endothelial function, measured as the reactive hyperemia index (P0.05), was observed.Our observations suggest that after LVAD implantation, low pulsatile flow up-regulates plasma levels of circulating flow-sensitive miRNAs, contributing to endothelial dysfunction and vascular remodeling.

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.

Background Implantation of left-ventricular assist systems (LVASs) has become the standard of care for advanced heart failure (HF). The absence of pulsatility in previous devices contributes to vascular and endothelial dysfunction related to atherosclerotic or vascular complications. We hypothesized that the artificial pulsatility provided by the HeartMate 3 (HM3) (Abbott, Chicago, IL) LVAS would exert a favourable effect on the vasculature. Methods In 32 patients implanted with HM3 (5 female patients, mean age 55 ± 13.6 years), the reactive hyperemia index (RHI) and peripheral augmentation index (AI), markers of endothelial function and arterial stiffness, were measured with an EndoPAT2000 before and in the third and sixth month after implantation. RHI and AI data from 30 HeartMate II (HM II) (Abbott) recipients in the third and sixth month after implantation, from 15 patients with advanced HF without LVASs and from 13 healthy volunteers were also analyzed. Results In HM3 recipients, the mean RHI significantly decreased at 3 and 6 months after implantation. The RHI was substantially lower at baseline than that of healthy or the HF reference group. Increasing AI values, indicating worsening arterial stiffness, were also observed. Similar trends were observed in HM II recipients between the third and sixth months but with higher absolute values of RHI and AI. Conclusions We detected impaired vascular function in HM3 patients and provided additional evidence on the negative effect of low pulsatility on vascular function after LVAS implantation. The results suggest that the artificial pulsatility of the HM3 does not avert the progression of endothelial dysfunction.

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.

Purpose Attenuation of physiological pulsatility after continuous flow left ventricular assist device (LVAD) implantation has been reported as a contributor to alteration of aortic wall morphology and function. MicroRNAs are non-coding RNAs that act to regulate translation of messenger RNA (mRNA) into proteins and are fine-tuners of gene expression in response to pathophysiological stimuli. Differences in gene expression (mRNA) and in post-transcriptional regulators (microRNAs) could reflect biological response to exposure to the low pulsatile environment. We hypothesized that pulsatility deficit caused by LVAD may influence miRNA/mRNA expression in aortic tissue. The aim of the study was to detect miRNA/mRNA associations in the aortic tissue during LVAD support. Methods Aortic samples were collected at the time of LVAD implant and at heart transplantation in 16 patients (mean age 49.6±16.8 years; 3 females) and examined for miRNA/mRNA profiling. QuantSeq 3′ mRNA-Sequencing was used to examine differences in gene expression. Using human miRNome panels a profile of 752 miRNAs was identified. Results A total of 277 mRNAs were dysregulated after LVAD support (padj Conclusion The study provides additional insight in pathophysiology of vascular changes after LVAD implantation. A significant regulation of mRNAs involved in ECM and collagen fibers organization in response to implantation of LVAD was observed, which may suggest infliction of ECM homeostasis resulting in changes of intrinsic properties of vascular wall and arterial stiffness. Downregulation of miRNAs involved in molecular processes related to immune response, could implicate dysregulation in inflammatory processes after LVAD implantation.

Background As a result of improved diagnostic methods, medical treatment, surgical correction, and palliation in childhood, there is a growing number of adult patients with congenital heart disease (CHD) who may experience heart failure and subsequently require heart transplantation (HT). Because of complex anatomy, previous operations, and frequently increased pulmonary vascular resistance (PVR), these patients represent a group with a higher risk of early mortality after transplantation. Methods From May 1999 to December 2014, our institution performed 25 HTs in adult patients with end-stage CHD. We present our data and outcomes of transplantation in this group. Results The median age at transplantation was 38 years (range, 18.4–53.7 years). Survival was 88% at 30 days, 88% at 1 year, and 77% at 5 years. We identified long donor heart ischemic time (>4 hours) as an important risk factor for early mortality. There was no significant difference in the survival of patients undergoing transplantation for CHD and patients undergoing transplantation for other diagnoses. Conclusions With careful donor and recipient selection, adults with end-stage CHD undergoing HT can achieve excellent early and midterm survival, comparable to the survival of patients who undergo transplantation for other diagnoses.

Purpose A pulsatility decrement caused by implantation of continuous flow left ventricular assist device (LVAD) has been corroborated as an additive factor further compromising aortic wall morphology and function. MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression which could reflect individual biologic adaptation to exposure to the low pulsatile environment. We hypothesized that pulsatility deficit caused by CF-LVAD implantation may influence miRNAs expression in aortic wall and that the miRNA profiles may differ between devices with different pulsatility profiles, such as speed modulated artificial pulse wave in HeartMate3. Methods Paired aortic samples obtained at the time of LVAD implantation and at the time of Heart transplantation from CF-LVAD patients were examined for miRNA profiling in ten patients (3 females; mean age 55±13.8 years, ischemic cardiomyopathy 40%; HeartMateII(n=4), HeartMate3 (n=6). Human miRNome profile (miRCURY LNA miRNA PCR panels) of 752 miRNAs using qPCR on QuantStudio6 RT-PCR instrument was performed in all samples. Results The mean support duration was 383.5±222.4 days (range 162 to 887 days). 25 differently expressed multifunctional miRNAs that contribute to the regulation of multiple signaling pathways were identified. The most significant differences in miRNAs expression between implant/explant samples were found in miR-99b-5p; -144-3p; -23b-3p; -30e-3p and let-7d-5p (all p Conclusion The study provides additional evidence on a negative effect of suppressed physiologic pulsatility amplitude in CF-LVAD patients. Negative changes predominantly in miRNAs participating in vascular tissue engineering in aortic wall and pro-inflammatory changes of miRNA profiles during LVAD duration were observed. Our observations suggest that a programmed artificial pulsatility in HeartMate3 does not provide mitigation of continuous flow effect on aortic wall. Moreover, the most up-expressed miR-99b which target ENO2 gene, a marker of neuronal injury, was detected after explant of LVAD. Larger scale adverse events matched clinical trials are warranted.

Decellularized human pericardium is under study as an allogenic material for cardiovascular applications. The effects of crosslinking on the mechanical properties of decellularized pericardium were determined with a uniaxial tensile test, and the effects of crosslinking on the collagen structure of decellularized pericardium were determined by multiphoton microscopy. The viability of human umbilical vein endothelial cells seeded on decellularized human pericardium and on pericardium strongly and weakly crosslinked with glutaraldehyde and with genipin was evaluated by means of an MTS assay. The viability of the cells, measured by their metabolic activity, decreased considerably when the pericardium was crosslinked with glutaraldehyde. Conversely, the cell viability increased when the pericardium was crosslinked with genipin. Coating both non-modified pericardium and crosslinked pericardium with a fibrin mesh or with a mesh containing attached heparin and/or fibronectin led to a significant increase in cell viability. The highest degree of viability was attained for samples that were weakly crosslinked with genipin and modified by means of a fibrin and fibronectin coating. The results indicate a method by which in vivo endothelialization of human cardiac allografts or xenografts could potentially be encouraged.

Purpose Heart failure is associated with impaired endothelial function including peripheral vessels. A pulsatility decrement once continuous flow left ventricular assist device (CF-LVAD) implanted has been consistently corroborated as an additive factor further compromising peripheral vascular function in such patients. EndoPAT 2000 is a FDA approved, operator independent device for assessment of endothelial function allowing for serial examination of reactive hyperemia index (RHI; as a measure of endothelial responsiveness; cutoff Methods Thirty-two patients implanted with HeartMate3 LVAS (5 females; mean age 55±13.8 years, ischemic cardiomyopathy 43.75%) were longitudinally examined by EndoPAT 2000 prior to the procedure and subsequently at 3rd and 6th month after implantation. Results Mean RHI was substantially impaired and below the norm already at a baseline (1.33±0.63). Temporal analysis revealed highly significant worsening at 3rd (RHI = 0.5±0.64) and 6th (RHI = 0.67±0.59) month post implantation (both p Conclusion The study provides additional evidence on a negative effect of suppressed physiologic pulsatility amplitude in CF-LVAD patients. Despite restored central hemodynamics, peripheral vascular function after implantation is further compromised based on serial assessment by EndoPAT 2000. Our observations suggest that a novel feature of programmed artificial pulsatility in HeartMate3 does not provide a sufficient pulse amplitude to avert further progression of peripheral vascular dysfunction due to continuous flow circulatory pattern. Larger scale adverse events matched clinical trials are warranted.

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.