The presence of cardiotropic viral genomes is not increased in atrial tissue of atrial fibrillation patients.

BACKGROUND: Infections with potentially cardiotropic viruses are associated with the development of atrial fibrillation (AF). However, whether direct viral infection of the atria is involved in the pathogenesis of AF is unclear. We have therefore analysed the presence of cardiotropic viral genomes in AF patients. METHODS: Samples of left atrial tissue were obtained from 50 AF patients (paroxysmal, n = 20; long-standing persistent/permanent, n = 30) during cardiac surgery and from autopsied control patients (n = 14). Herein, the presence of PVB19, EBV, CMV, HHV­6, adenovirus and enterovirus genomes was determined by polymerase chain reaction. The densities of CD45+ and CD3+ cells and fibrosis in the atria were quantified by (immuno)histochemistry. RESULTS: Of the tested viruses only the PVB19 genome was detected in the atria of 10% of patients, paroxysmal AF (2 of 20) and long-standing persistent/permanent AF (3 of 30). Conversely, in 50% of controls (7 of 14) PVB19 genome was found. No significant association was found between PVB19 and CD45+ and CD3+ cells, or between the presence of PVB19 and fibrosis, in either control or AF patients. CONCLUSION: The presence of viral genomes is not increased in the atria of AF patients. These results do not support an important role for viral infection of the atria in the pathogenesis of AF.

Atrial inflammation in different atrial fibrillation subtypes and its relation with clinical risk factors.

OBJECTIVE: Inflammation of the atria is an important factor in the pathogenesis of atrial fibrillation (AF). Whether the extent of atrial inflammation relates with clinical risk factors of AF, however, is largely unknown. This we have studied comparing patients with paroxysmal and long-standing persistent/permanent AF. METHODS: Left atrial tissue was obtained from 50 AF patients (paroxysmal = 20, long-standing persistent/permanent = 30) that underwent a left atrial ablation procedure either or not in combination with coronary artery bypass grafting and/or valve surgery. Herein, the numbers of CD45+ and CD3+ inflammatory cells were quantified and correlated with the AF risk factors age, gender, diabetes, and blood CRP levels. RESULTS: The numbers of CD45+ and CD3+ cells were significantly higher in the adipose tissue of the atria compared with the myocardium in all AF patients but did not differ between AF subtypes. The numbers of CD45+ and CD3+ cells did not relate significantly to gender or diabetes in any of the AF subtypes. However, the inflammatory infiltrates as well as CK-MB and CRP blood levels increased significantly with increasing age in long-standing persistent/permanent AF and a moderate positive correlation was found between the extent of atrial inflammation and the CRP blood levels in both AF subtypes. CONCLUSION: The extent of left atrial inflammation in AF patients was not related to the AF risk factors, diabetes and gender, but was associated with increasing age in patients with long-standing persistent/permanent AF. This may be indicative for a role of inflammation in the progression to long-standing persistent/permanent AF with increasing age.

Hemangioma of the Atherosclerotic Changed Aortic Valve.

The incidence of heart valve hemangioma is very low and is mostly observed in the mitral and tricuspid valve. In 2006, two cases of aortic valve hemangioma were reported for the first time, including one with calcifying aortic valve stenosis. We now present a case of aortic valve hemangioma in a patient suffering from aortic valve insufficiency combined with atherosclerotic thickening.

Postoperative microcirculatory perfusion and endothelial glycocalyx shedding following cardiac surgery with cardiopulmonary bypass.

We investigated microcirculatory perfusion disturbances following cardiopulmonary bypass in the early postoperative period and whether the course of these disturbances mirrored restoration of endothelial glycocalyx integrity. We performed sublingual sidestream dark field imaging of the microcirculation during the first three postoperative days in patients who had undergone on-pump coronary artery bypass graft surgery. We calculated the perfused vessel density, proportion of perfused vessels and perfused boundary region. Plasma was obtained to measure heparan sulphate and syndecan-1 levels as glycocalyx shedding markers. We recruited 17 patients; the mean (SD) duration of non-pulsatile cardiopulmonary bypass was 103 (18) min, following which 491 (29) ml autologous blood was transfused through cell salvage. Cardiopulmonary bypass immediately decreased both microcirculatory perfused vessel density; 11 (3) vs. 16 (4) mm.mm-2 , p = 0.052 and the proportion of perfused vessels; 92 (5) vs. 69 (9) %, p < 0.0001. The proportion of perfused vessels did not increase after transfusion of autologous salvaged blood following cardiopulmonary bypass; 72 (7) %, p = 0.19 or during the first three postoperative days; 71 (5) %, p < 0.0001. The perfused boundary region increased after cardiopulmonary bypass; 2.2 (0.3) vs. 1.9 (0.3) µm, p = 0.037 and during the first three postoperative days; 2.4 (0.3) vs. 1.9 (0.3) µm, p = 0.003. Increased plasma heparan sulphate levels were inversely associated with the proportion of perfused vessels during cardiopulmonary bypass; R = -0.49, p = 0.02. Plasma syndecan-1 levels were inversely associated with the proportion of perfused vessels during the entire study period; R = -0.51, p < 0.0001. Our study shows that cardiopulmonary bypass-induced acute microcirculatory perfusion disturbances persist in the first three postoperative days, and are associated with prolonged endothelial glycocalyx shedding. This suggests prolonged impairment and delayed recovery of both microcirculatory perfusion and function after on-pump cardiac surgery.

Vasculotide, an angiopoietin-1 mimetic, reduces pulmonary vascular leakage and preserves microcirculatory perfusion during cardiopulmonary bypass in rats.

BACKGROUND: Cardiopulmonary bypass (CPB) during cardiac surgery impairs microcirculatory perfusion and is paralleled by vascular leakage. The endothelial angiopoietin/Tie2 system controls microvascular leakage. This study investigated whether targeting Tie2 with the angiopoietin-1 mimetic vasculotide reduces vascular leakage and preserves microcirculatory perfusion in a rat CPB model. METHODS: Rats were subjected to 75 min of CPB after treatment with vasculotide or phosphate buffered solution as control or underwent a sham procedure. Microcirculatory perfusion and leakage were assessed with intravital microscopy (n=10 per group) and Evans blue dye extravasation (n=13 per group), respectively. Angiopoietin-1, -2, and Tie2 protein and gene expression were determined in plasma, kidney, and lung. RESULTS: CPB immediately impaired microcirculatory perfusion [5 (4-8) vs 10 (7-12) vessels per recording, P=0.002] in untreated CPB rats compared with sham, which persisted after weaning from CPB. CPB increased circulating angiopoeietin-1, -2, and soluble Tie2 concentrations and reduced Tie2 messenger ribonucleic acid (mRNA) expression in kidney and lung. Moreover, CPB increased Evans blue dye leakage in kidney [12 (8-25) vs 7 (1-12) µg g-1, P=0.04] and lung [and 23 (13-60) vs 6 (4-16) µg g-1, P=0.001] compared with sham. Vasculotide treatment preserved microcirculatory perfusion during and after CPB. Moreover, vasculotide treatment reduced Evans blue dye extravasation in lung compared with CPB control [18 (6-28) µg g-1vs 23 (13-60) µg g-1, P=0.04], but not in kidney [10 (3-23) vs 12 (8-25) µg g-1, P=0.38]. Vasculotide did not affect circulating or mRNA expression of angiopoietin-1, -2, and Tie2 concentrations compared with untreated CPB controls. CONCLUSIONS: Treatment with the angiopoietin-1 mimetic vasculotide reduced pulmonary vascular leakage and preserved microcirculatory perfusion during CPB in a rat model.

Reduction of vascular leakage by imatinib is associated with preserved microcirculatory perfusion and reduced renal injury markers in a rat model of cardiopulmonary bypass.

BACKGROUND: Cardiopulmonary bypass during cardiac surgery leads to impaired microcirculatory perfusion. We hypothesized that vascular leakage is an important contributor to microcirculatory dysfunction. Imatinib, a tyrosine kinase inhibitor, has been shown to reduce vascular leakage in septic mice. We investigated whether prevention of vascular leakage using imatinib preserves microcirculatory perfusion and reduces organ injury markers in a rat model of cardiopulmonary bypass. METHODS: Male Wistar rats underwent cardiopulmonary bypass after treatment with imatinib or vehicle (n=8 per group). Cremaster muscle microcirculatory perfusion and quadriceps microvascular oxygen saturation were measured using intravital microscopy and reflectance spectroscopy. Evans Blue extravasation was determined in separate experiments. Organ injury markers were determined in plasma, intestine, kidney, and lungs. RESULTS: The onset of cardiopulmonary bypass decreased the number of perfused microvessels by 40% in the control group [9.4 (8.6-10.6) to 5.7 (4.8-6.2) per microscope field; P<0.001 vs baseline], whereas this reduction was not seen in the imatinib group. In the control group, the number of perfused capillaries remained low throughout the experiment, whilst perfusion remained normal after imatinib administration. Microvascular oxygen saturation was less impaired after imatinib treatment compared with controls. Imatinib reduced vascular leakage and decreased fluid resuscitation compared with control [3 (3-6) vs 12 ml (7-16); P=0.024]. Plasma neutrophil-gelatinase-associated-lipocalin concentrations were reduced by imatinib. CONCLUSIONS: Prevention of endothelial barrier dysfunction using imatinib preserved microcirculatory perfusion and oxygenation during and after cardiopulmonary bypass. Moreover, imatinib-induced protection of endothelial barrier integrity reduced fluid-resuscitation requirements and attenuated renal and pulmonary injury markers.

Anticoagulant and side-effects of protamine in cardiac surgery: a narrative review.

Neutralisation of systemic anticoagulation with heparin in cardiac surgery with cardiopulmonary bypass requires protamine administration. If adequately dosed, protamine neutralises heparin and reduces the risk of postoperative bleeding. However, as its anticoagulant properties are particularly exerted in the absence of heparin, overdosing of protamine may contribute to bleeding and increased transfusion requirements. This narrative review describes the mechanisms underlying the anticoagulant properties and side-effects of protamine, and the impact of protamine dosing on the activated clotting time and point-of-care viscoelastic test results, and explains the distinct protamine dosing strategies in relation to haemostatic activation and postoperative bleeding. The available evidence suggests that protamine dosing should not exceed a protamine-to-heparin ratio of 1:1. In particular, protamine-to-heparin dosing ratios >1 are associated with more postoperative 12 h blood loss. The optimal protamine-to-heparin ratio in cardiac surgery has, however, not yet been elaborated, and may vary between 0.6 and 1.0 based on the initial heparin dose.

Individual Differences in Heparin Sensitivity and Their Effect on Heparin Anticoagulation During Arterial Vascular Surgery.

OBJECTIVES: To investigate whether a fixed heparin dose results in adequate heparinisation levels and consequent inhibition of haemostatic activation in all patients. METHODS: This prospective clinical pilot study included 24 patients undergoing arterial vascular surgery. Individual heparin responsiveness was assessed using the Heparin Dose Response (HDR) test, while the activated clotting time (ACT) and heparin concentration were measured to monitor the peri-procedural degree of anticoagulation. Finally, peri-operative haemostasis was evaluated with rotational thromboelastometry (ROTEM). RESULTS: Eight patients were identified with reduced heparin sensitivity (RS group) and 16 patients with normal heparin sensitivity (NS group). Compared with the NS group, the RS group showed less prolonged ACTs after heparinisation with heparin concentrations below the calculated target heparin concentration. ROTEM revealed shorter clot formation times in the intrinsically activated coagulation test (INTEM) 3 min (114 ± 48 s vs. 210 ± 128 s) and 30 min after the initial heparin bolus (103 ± 48 s vs. 173 ± 81 s) in the RS group compared with the NS group. In the RS group, one patient developed a major thromboembolic complication. CONCLUSIONS: This study shows that a third of the study population had reduced heparin sensitivity, which was associated with lower levels of heparinisation, and lower inhibition levels of clot initiation and clot formation. Identifying patients with reduced heparin sensitivity by monitoring the anticoagulant effect of heparin could decrease the risk of thrombotic complications after arterial vascular surgery.

Validation of a point-of-care prothrombin time test after cardiopulmonary bypass in cardiac surgery.

Point-of-care coagulation monitoring can be used for the guidance of haemostasis management. However, the influence of time on point-of-care prothrombin time testing following protamine administration after cardiopulmonary bypass has not been investigated. Bland-Altman and error grid analysis were used to analyse the level of agreement between prothrombin time measurements from point-of-care and laboratory tests before cardiopulmonary bypass, and then 3 min, 6 min and 10 min after protamine administration. Prothrombin times were expressed as International Normalised Ratios. While the point-of-care and laboratory prothrombin time measurements showed a high level of agreement before bypass, this agreement deteriorated following protamine administration to a mean (SD) bias of -0.22 (0.13) [limits of agreement 0.48-0.04]. Error grid analysis revealed that 35 (70%) of the paired values showed a clinically relevant discrepancy in international normalised ratio. At 3 min, 6 min and 10 min after cardiopulmonary bypass there is a clinical unacceptable discrepancy between the point-of-care and laboratory measurement of prothrombin time.

Endothelial hyperpermeability after cardiac surgery with cardiopulmonary bypass as assessed using an in vitro bioassay for endothelial barrier function.

BACKGROUND: The mechanisms causing increased endothelial permeability after cardiopulmonary bypass (CPB) have not been elucidated. Using a bioassay for endothelial barrier function, we investigated whether endothelial hyperpermeability is associated with alterations in plasma endothelial activation and adhesion markers and can be attenuated by the use of pulsatile flow during CPB. METHODS: Patients undergoing cardiac surgery were randomized to non-pulsatile (n=20) or pulsatile flow CPB (n=20). Plasma samples were obtained before (pre-CPB) and after CPB (post-CPB), and upon intensive care unit (ICU) arrival. Changes in plasma endothelial activation and adhesion markers were determined by enzyme-linked immunosorbent assay. Using electric cell-substrate impedance sensing of human umbilical vein endothelial monolayers, the effects of plasma exposure on endothelial barrier function were assessed and expressed as resistance. RESULTS: Cardiopulmonary bypass was associated with increased P-selectin, vascular cell adhesion molecule-1, and von Willebrand factor plasma concentrations and an increase in the angiopoietin-2 to angiopoietin-1 ratio, irrespective of the flow profile. Plasma samples obtained after CPB induced loss of endothelial resistance of 21 and 23% in non-pulsatile and pulsatile flow groups, respectively. The negative effect on endothelial cell barrier function was still present with exposure to plasma obtained upon ICU admission. The reduction in endothelial resistance after exposure to post-CPB plasma could not be explained by CPB-induced haemodilution. CONCLUSION: The change in the plasma fingerprint during CPB is associated with impairment of in vitro endothelial barrier function, which occurs irrespective of the application of a protective pulsatile flow profile during CPB. CLINICAL TRIAL REGISTRATION: NTR2940.

Trends in incidence of infective endocarditis at the Medical Center of Alkmaar.

INTRODUCTION: Infective endocarditis (IE) is a life-threatening illness with a high morbidity and mortality, and with a rise in incidence in patients with prosthetic valves and cardiac devices. Recently the Dutch guidelines of IE prophylaxis have been revised, limiting IE prophylaxis to the highest-risk population. The aim of the present study was to investigate the incidence of IE and its trend between 2008-2013 in a regional hospital in the Netherlands. METHODS: This is an observational descriptive study of all patients who were admitted with IE to the Medical Center of Alkmaar (MCA) from 1 January 2008 to 31 December 2013. RESULTS: A total of 89 patients with IE, including 7 patients (7.9 %) with a cardiac device IE (CDIE), were identified. In 2008 there were 8 patients with IE, this increased to 26 patients in 2013. Patients with a prosthetic valve IE increased from 25 % in 2008 to 34.6 % in 2013. This increase was not seen in patients with CDIE. CONCLUSION: In the MCA we have observed an increase in patients with IE since 2010. This increase was in part attributable to prosthetic valve IE. A larger observational study is needed to investigate the increase of IE in the Netherlands.

ENerGetIcs in hypertrophic cardiomyopathy: traNslation between MRI, PET and cardiac myofilament function (ENGINE study).

INTRODUCTION: Hypertrophic cardiomyopathy (HCM) is an autosomal dominant heart disease mostly due to mutations in genes encoding sarcomeric proteins. HCM is characterised by asymmetric hypertrophy of the left ventricle (LV) in the absence of another cardiac or systemic disease. At present it lacks specific treatment to prevent or reverse cardiac dysfunction and hypertrophy in mutation carriers and HCM patients. Previous studies have indicated that sarcomere mutations increase energetic costs of cardiac contraction and cause myocardial dysfunction and hypertrophy. By using a translational approach, we aim to determine to what extent disturbances of myocardial energy metabolism underlie disease progression in HCM. METHODS: Hypertrophic obstructive cardiomyopathy (HOCM) patients and aortic valve stenosis (AVS) patients will undergo a positron emission tomography (PET) with acetate and cardiovascular magnetic resonance imaging (CMR) with tissue tagging before and 4 months after myectomy surgery or aortic valve replacement + septal biopsy. Myectomy tissue or septal biopsy will be used to determine efficiency of sarcomere contraction in-vitro, and results will be compared with in-vivo cardiac performance. Healthy subjects and non-hypertrophic HCM mutation carriers will serve as a control group. ENDPOINTS: Our study will reveal whether perturbations in cardiac energetics deteriorate during disease progression in HCM and whether these changes are attributed to cardiac remodelling or the presence of a sarcomere mutation per se. In-vitro studies in hypertrophied cardiac muscle from HOCM and AVS patients will establish whether sarcomere mutations increase ATP consumption of sarcomeres in human myocardium. Our follow-up imaging study in HOCM and AVS patients will reveal whether impaired cardiac energetics are restored by cardiac surgery.

Long-term outcomes of isolated aortic valve replacement and concomitant AVR and coronary artery bypass grafting.

BACKGROUND: It is well established that concomitant aortic valve replacement (AVR) and coronary artery bypass grafting (CABG) has a higher operative mortality rate than isolated AVR. However, studies report conflicting results on the long-term mortality. The aim of this prospective study was to explore and compare the outcomes and risk factors of isolated AVR and concomitant AVR and CABG in a consecutive Dutch patient population. METHODS: From January 2001 through January 2010, 332 consecutive patients underwent AVR with or without CABG at a single institution (197 isolated AVR and 135 concomitant AVR and CABG). A multivariate Cox proportional hazard analysis was performed to determine the independent risk factors for long-term mortality after aortic valve replacement. RESULTS: All 332 consecutive, referred patients who underwent aortic valve surgery were followed for up to 10 years. Median follow-up length was 48 months. The population had a median age of 73 years (IQR 65-78) and predominantly consisted of males (62%). Patients in the combined AVR and CABG group were older, had worse cardiac risk profiles and had worse preoperative cardiac statuses than those receiving isolated AVR. Five-year survival was 85% in AVR and 73% in AVR-CABG (p-value 0.012). Independent risk factors for mortality were higher creatinine values, previous CABG and increasing age. CONCLUSION: Unselected, consecutive patients who underwent aortic valve replacement surgery and who received concomitant bypass surgery between 2001-2010 had higher 5-year mortality than their counterparts without CABG. Prior CABG, renal function, age but not concomitant CABG remained independently associated with increased mortality. Finally, the observed mortality rate in this consecutive patient group compared favourably with preoperative risk assessment using the EuroSCORE.

Reduction of infarct size by intravenous injection of uncultured adipose derived stromal cells in a rat model is dependent on the time point of application.

Stem cell therapy is a promising tool to improve outcome after acute myocardial infarction (AMI), but needs to be optimized since results from clinical applications remain ambiguous. A potent source of stem cells is the stromal vascular fraction of adipose tissue (SVF), which contains high numbers of adipose derived stem cells (ASC). We hypothesized that: 1) intravenous injection can be used to apply stem cells to the heart. 2) Uncultured SVF cells are easier and safer when cultured ASCs. 3) Transplantation after the acute inflammation period of AMI is favorable over early injection. For this, AMI was induced in rats by 40min of coronary occlusion. One or seven days after AMI, rats were intravenously injected with vehicle, 5×10(6) uncultured rat SVF cells or 1×10(6) rat ASCs. Rats were analyzed 35 days after AMI. Intravenous delivery of both fresh SVF cells and cultured ASCs 7 days after AMI significantly reduced infarct size compared to vehicle. Similar numbers of stem cells were found in the heart, after treatment with fresh SVF cells and cultured ASCs. Importantly, no adverse effects were found after injection of SVF cells. Using cultured ASCs, however, 3 animals had shortness of breath, and one animal died during injection. In contrast to application at 7 days post AMI, injection of SVF cells 1 day post AMI resulted in a small but non-significant infarct reduction (p=0.35). Taken together, intravenous injection of uncultured SVF cells subsequent to the acute inflammation period, is a promising stem cell therapy for AMI.

Activated complement is more extensively present in diseased aortic valves than naturally occurring complement inhibitors: a sign of ongoing inflammation.

BACKGROUND: Recent studies indicate a role for complement in the pathogenesis of aortic valve disease. However, the role of naturally occurring anti-complement mediators in this context is unknown. In this study, we have analysed this in three different pathological conditions of the aortic valve: degeneration, atherosclerosis and bacterial endocarditis. MATERIALS AND METHODS: Human aortic valves were obtained at autopsy (n = 30): 5 control valves, 10 aortic valves with atherosclerotic changes, 10 aortic valves with degenerative changes and 5 degenerative changed aortic valves with bacterial infection. These valves were analysed immunohistochemically for the presence of activated complement (C3d and C5b9) and the complement inhibitors C1-inh and clusterin. Areas of positivity were then quantified. RESULTS: C3d, C5b9 and the complement inhibitors C1-inh and clusterin depositions were mainly found in the endothelium and extracellular matrix in aortic valves. All these mediators were already present in control valves, but the area of positivity increased significantly in response to the different diseases, with the highest increase in response to bacterial endocarditis. Interestingly, in all three aortic diseases, the depositions of complement were significantly more widespread than that of their inhibitors. CONCLUSIONS: Our study indicates that anti-complement mediators (C1-inh and clusterin) are deposited in diseased aortic valves together with activated complement, indicating an existing counter response against complement locally in the valve. However, deposition of activated complement is significantly more widespread than that of its inhibitors, which could explain ongoing inflammation in those diseased aortic valves.