Effects of cardiopulmonary bypass on leukocyte and endothelial adhesion molecules

Cardiac Surgery-Associated Acute Kidney Injury

AKI is a common and serious complication of cardiac surgery that has a significant impact on patient morbidity and mortality. The Kidney Disease Improving Global Outcomes definition of AKI is widely used to classify and identify AKI associated with cardiac surgery (cardiac surgery-associated AKI [CSA-AKI]) on the basis of changes in serum creatinine and/or urine output. There are various preoperative, intraoperative, and postoperative risk factors for the development of CSA-AKI which should be recognized and addressed as early as possible to expedite its diagnosis, reduce its occurrence, and prevent or ameliorate its devastating complications. Crucial issues are the inaccuracy of serum creatinine as a surrogate parameter of kidney function in the perioperative setting of cardiothoracic surgery and the necessity to discover more representative markers of the pathophysiology of AKI. However, except for the tissue inhibitor of metalloproteinase-2 and insulin-like growth factor binding protein 7 ratio, other diagnostic biomarkers with an acceptable sensitivity and specificity are still lacking. This article provides a comprehensive review of various aspects of CSA-AKI, including pathogenesis, risk factors, diagnosis, biomarkers, classification, prevention, and treatment management.

Adverse renal effects associated with cardiopulmonary bypass

Cardiac surgery on cardiopulmonary bypass (CPB) is associated with postoperative renal dysfunction, one of the most common complications of this surgical cohort. Acute kidney injury (AKI) is associated with increased short-term morbidity and mortality and has been the focus of much research. There is increasing recognition of the role of AKI as the key pathophysiological state leading to the disease entities acute and chronic kidney disease (AKD and CKD). In this narrative review, we will consider the epidemiology of renal dysfunction after cardiac surgery on CPB and the clinical manifestations across the spectrum of disease. We will discuss the transition between different states of injury and dysfunction, and, importantly, the relevance to clinicians. The specific facets of kidney injury on extracorporeal circulation will be described and the current evidence evaluated for the use of perfusion-based techniques to reduce the incidence and mitigate the complications of renal dysfunction after cardiac surgery.

Diagnosis, pathophysiology and preventive strategies for cardiac surgery-associated acute kidney injury: a narrative review

Acute kidney injury (AKI) is a common and serious complication of cardiac surgery and is associated with increased mortality and morbidity, accompanied by a substantial economic burden. The pathogenesis of cardiac surgery-associated acute kidney injury (CSA-AKI) is multifactorial and complex, with a variety of pathophysiological theories. In addition to the existing diagnostic criteria, the exploration and validation of biomarkers is the focus of research in the field of CSA-AKI diagnosis. Prevention remains the key to the management of CSA-AKI, and common strategies include maintenance of renal perfusion, individualized blood pressure targets, balanced fluid management, goal-directed oxygen delivery, and avoidance of nephrotoxins. This article reviews the pathogenesis, definition and diagnosis, and pharmacological and nonpharmacological prevention strategies of AKI in cardiac surgical patients.

Acute Cardiac Care for Neonatal Heart Disease

This manuscript is one component of a larger series of articles produced by the Neonatal Cardiac Care Collaborative that are published in this supplement of Pediatrics. In this review article, we summarize the contemporary physiologic principles, evaluation, and management of acute care issues for neonates with complex congenital heart disease. A multidisciplinary team of authors was created by the Collaborative's Executive Committee. The authors developed a detailed outline of the manuscript, and small teams of authors were assigned to draft specific sections. The authors reviewed the literature, with a focus on original manuscripts published in the last decade, and drafted preliminary content and recommendations. All authors subsequently reviewed and edited the entire manuscript until a consensus was achieved. Topics addressed include cardiopulmonary interactions, the pathophysiology of and strategies to minimize the development of ventilator-induced low cardiac output syndrome, common postoperative physiologies, perioperative bleeding and coagulation, and common postoperative complications.

Lessons Learned From the First Pilot Study of the Compensatory Reserve Index After Congenital Heart Surgery Requiring Cardiopulmonary Bypass

BACKGROUND

Early warning systems that utilize dense physiologic data and machine learning may aid prediction of decompensation after congenital heart surgery (CHS). The Compensatory Reserve Index (CRI) analyzes changing features of the pulse waveform to predict hemodynamic decompensation in adults, but it has never been studied after CHS. This study sought to understand the feasibility, safety, and potential utility of CRI monitoring after CHS with cardiopulmonary bypass (CPB).

METHODS

A single-center prospective pilot cohort of patients undergoing pulmonary valve replacement was studied. Compensatory Reserve Index was continuously measured from preoperative baseline through the first 24 postoperative hours. Average CRI values during selected procedural phases were compared between patients with an intensive care unit (ICU) length of stay (LOS) <3 days versus LOS ≥3 days.

RESULTS

Twenty-three patients were enrolled. On average, 17,445 (±3,152) CRI data points were collected and 0.33% (±0.40) of data were missing per patient. There were no adverse events related to monitoring. Five (21.7%) patients had an ICU LOS ≥3 days. Compared to the ICU LOS <3 days group, the ICU LOS ≥3 days group had a greater decrease in CRI from baseline to immediately after CPB (-0.3 ± 0.1 vs -0.1 ± 0.2, P = .003) and were less likely to recover to baseline CRI during the monitoring period (20% vs 83%, P = .017).

CONCLUSIONS

Compensatory Reserve Index monitoring after CHS with CPB seems feasible and safe. Early changes in CRI may precede meaningful clinical outcomes, but this requires further study.

Preventative and Therapeutic Potential of Flavonoids in Peptic Ulcers

Peptic ulcer disease is a common gastrointestinal tract disorder that affects up to 20% of the population of the world. Treatment of peptic ulcer remains challenging due to the limited effectiveness and severe side effects of the currently available drugs. Hence, natural compounds, owing to their medicinal, ecological, and other safe properties, are becoming popular potential candidates in preventing and treating peptic ulcers. Flavonoids, the most abundant polyphenols in plants, exhibit gastroprotective effects against peptic ulcer both in vivo and in vitro. In this review, we summarized the anti-ulcer functions and mechanisms, and also the bioavailability, efficacy, and safety, of flavonoid monomers in the gastrointestinal tract. Flavonoids exerted cytoprotective and rehabilitative effects by not only strengthening defense factors, such as mucus and prostaglandins, but also protecting against potentially harmful factors via their antioxidative, anti-inflammatory, and antibacterial activities. Although controlled clinical studies are limited at present, flavonoids have shown a promising preventable and therapeutic potential in peptic ulcers.

Minimally invasive extracorporeal circulation is a cost-effective alternative to conventional extracorporeal circulation for coronary artery bypass grafting: propensity matched analysis

INTRODUCTION

Minimally invasive extracorporeal circulation has developed with the aim of reducing the impact of the adverse effects associated with conventional extracorporeal circulation. The aim of this study was to compare outcomes for patients undergoing coronary artery bypass grafting using minimally invasive extracorporeal circulation with those performed using conventional extracorporeal circulation.

METHODS

A retrospective analysis was performed of patients undergoing minimally invasive extracorporeal circulation coronary artery bypass grafting at a single centre. 2:1 propensity matching was performed to identify control patients undergoing conventional extracorporeal circulation coronary artery bypass grafting. Outcomes were compared using univariate analysis.

RESULTS

A total of 354 patients were included in the study, with 118 patients undergoing minimally invasive extracorporeal circulation coronary artery bypass grafting. Patients were well matched on baseline characteristics. The mean logistic EuroSCORE was 3.95 ± 4.20. Operative times (3.31 ± 1.52 vs. 3.56 ± 0.73, p = 0.03) were significantly shorter in minimally invasive extracorporeal circulation cases. Patients who underwent surgery with minimally invasive extracorporeal circulation had significantly less 12-hour blood loss (322.3 ± 13.2 mL vs. 380.8 ± 15.2 mL, p < 0.01). Correspondingly, a significantly lower proportion of patients were transfused (25.8% vs. 36%, p = 0.04), and the mean number of red blood cells transfused was lower (0.45 ± 0.95 vs. 0.97 ± 2.13, p = 0.01). Similarly, the number of coagulation products administered was lower (0.161 ± 0.05 vs. 0.40 ± 0.09, p = 0.05). There was a significantly lower incidence of acute kidney injury (11.0% vs. 19.9%, p = 0.03). Minimally invasive extracorporeal circulation was associated with a £679.50 cost saving per patient.

DISCUSSION

Minimally invasive extracorporeal circulation for coronary artery bypass grafting is associated with a reduced requirement for blood transfusion, reduced incidence of acute kidney injury and a significant cost saving. Minimally invasive extracorporeal circulation should be considered as an adjunct for all patients undergoing coronary artery bypass grafting.

The Inflammatory Response to Ventricular Assist Devices

The therapeutic use of ventricular assist devices (VADs) for end-stage heart failure (HF) patients who are ineligible for transplant has increased steadily in the last decade. In parallel, improvements in VAD design have reduced device size, cost, and device-related complications. These complications include infection and thrombosis which share underpinning contribution from the inflammatory response and remain common risks from VAD implantation. An added and underappreciated difficulty in designing a VAD that supports heart function and aids the repair of damaged myocardium is that different types of HF are accompanied by different inflammatory profiles that can affect the response to the implanted device. Circulating inflammatory markers and changes in leukocyte phenotypes receive much attention as biomarkers for mortality and disease progression. However, they are seldom used to monitor progress during and outcomes from VAD therapy or during the design phase for new devices. Even the partial reversal of heart damage associated with heart failure is a desirable outcome from VAD use. Therefore, improved understanding of the interplay between VADs and the recipient's inflammatory response would potentially increase their uptake, improve patient lives, and fuel research related to other blood-contacting medical devices. Here we provide a review of what is currently known about inflammation in heart failure and how this inflammatory profile is altered in heart failure patients receiving VAD therapy.

Hemocompatibility of Degrading Polymeric Biomaterials: Degradable Polar Hydrophobic Ionic Polyurethane versus Poly(lactic-co-glycolic) Acid

The use of degradable polymers in vascular tissue regeneration has sparked the need to characterize polymer biocompatibility during degradation. While tissue compatibility has been frequently addressed, studies on polymer hemocompatibility during degradation are limited. The current study evaluated the differences in hemocompatibility (platelet response, complement activation, and coagulation cascade initiation) between as-made and hydrolyzed poly(lactic-co-glycolic) acid (PLGA) and degradable polar hydrophobic ionic polyurethane (D-PHI). Platelet activation decreased (in whole blood) and platelet adhesion decreased (in blood without leukocytes) for degraded versus as-made PLGA. D-PHI showed minimal hemocompatibility changes over degradation. Leukocytes played a major role in mediating platelet activation for samples and controls, as well as influencing platelet-polymer adhesion on the degraded materials. This study demonstrates the importance of assessing the blood compatibility of biomaterials over the course of degradation since the associated changes in surface chemistry and physical state could significantly change biomaterial hemocompatibility.

Leukocyte filtration and aprotinin: synergistic anti-inflammatory protection

Cardiopulmonary bypass activates an array of cellular and humoral inflammatory mechanisms that culminate in diverse or organ-specific injury. A manifestation of inflammatory injury to the heart, atrial fibrillation ranks among the most frequent and potentially life-threatening postsurgical complications. Pulmonary manifestations of the inflammatory response are also of major concern. Neutrophils activated by passage through the extracorporeal circuit inflict local injury and provoke the inflammatory cascade by producing oxyradicals and proinflammatory factors. This study tested if a combination of leukocyte depletion and aprotinin suppression of neutrophils could minimize postbypass atrial fibrillation and pulmonary dysfunction. In part one, two randomized groups of 90 patients undergoing primary coronary artery bypass grafting received full Hammersmith aprotinin alone (control group) or combined with leukofiltration (study group) and were prospectively examined. The dual treatment decreased the incidence of postoperative atrial fibrillation (7 of 90, 7.8%) by 67% versus aprotinin alone (21 of 90, 23.3%). Respiratory gas exchange in these patients was assessed from pulmonary shunt fraction. In the first two hours postbypass, pulmonary shunt fraction in the dual treatment group increased 40% less than in the group receiving aprotinin alone (p = 0.002), and subsided more quickly and completely over the next six hours. In part two, the cardiopulmonary bypass group receiving aprotinin+leukofiltration was retrospectively compared with 45 patients undergoing off-pump coronary revascularization. A strong, albeit not statistically significant trend (p= 0.08) toward a lower incidence of atrial fibrillation was found in the dual treatment group versus the off-pump group (8 of 45, 17.8%). These findings suggest that combining mechanical and pharmacologic suppression of the systemic inflammatory response could mitigate its deleterious arrhythmic and pulmonary complications.

Management of the Low Cardiac Output Syndrome Following Surgery for Congenital Heart Disease

The purpose of this review is to discuss the management of the low cardiac output syndrome (LCOS) following surgery for congenital heart disease. The LCOS is a well-recognized, frequent post-operative complication with an accepted collection of hemodynamic and physiologic aberrations. Approximately 25% of children experience a decrease in cardiac index of less than 2 L/min/m2 within 6-18 hours after cardiac surgery. Post-operative strategies that may be used to manage patients as risk for or in a state of low cardiac output include the use of hemodynamic monitoring, enabling a timely and accurate assessment of cardiovascular function and tissue oxygenation; optimization of ventricular loading conditions; the judicious use of inotropic agents; an appreciation of and the utilization of positive pressure ventilation for circulatory support; and, in some circumstances, mechanical circulatory support. All interventions and strategies should culminate in improving the relationship between oxygen supply and demand, ensuring adequate tissue oxygenation.

Leukocyte removal efficiency of cell-washed and unwashed whole blood: an in vitro study

Leukocyte filtration of the cardiopulmonary bypass (CPB) perfusate after cardiac surgery has evolved as an important technique to prevent effector functions mediated by activated leukocytes. However, little is known about the filtration efficiency. Therefore, an in vitro study was conducted to define the leukocyte removal rate of a transfusion leukocyte-depletion filter, using cell-washed and unwashed whole porcine blood. In addition, the influence of different cell-washing protocols on the elimination rate of blood cells (leukocytes and platelets) was investigated.

Fresh, diluted, pooled, heparinized, porcine blood was processed using either a high-flow (HF, n-5) or quality-wash (QW, n-5) protocol on a continuous auto-transfusion system, or was left unprocessed (control n-5). Thereafter, all samples were filtered using a transfusion leukocyte-depletion filter. Blood samples for measurement of hematocrit, white blood cell count, including leukocyte differentiation and platelet count, were taken before and after filtration. To compare the experimental groups, the removal rate was presented as the fraction of leukocytes or platelets removed per plasma volume.

Cell washing significantly altered the fraction of leukocytes removed per plasma volume when compared to unprocessed blood (2.07 and 2.36 in the HF and QW groups, respectively, versus 1.34 in the control group, p-0.008 for both). No statistically significant difference in leukocyte removal rate was observed between the different cell-washing protocols. The leukocyte differential count showed that, during all experiments, the neutrophils were removed most efficiently (99.7%). Overall, significantly more platelets were depleted after cell washing compared to the control group (1.47 and 1.60 in the HF and QW groups, respectively, versus 1.12 in the control group, p-0.008 and 0.032, respectively). Furthermore, the amount of blood that could be filtered using a single pass technique did not significantly differ between the experimental groups. However, a larger variation in the total amount of filtered blood was observed in the unprocessed group (5709/398 mL) compared to the cell-washed groups (3609/42 and 4309/97 mL in the HF and QW groups, respectively).

In conclusion, blood processing with an auto-transfusion system significantly enhances the leukocyte and platelet removal efficiency of the transfusion leukocyte-depletion filter that was studied. In particular, neutrophils were efficiently removed.

Off-Pump Coronary Artery Bypass Surgery

Off-pump coronary artery bypass surgery has been adopted enthusiastically worldwide. However, despite more than 6 years’ experience and refinement, many surgeons use it only sporadically and some hardly at all. This reluctance persists despite support for the procedure because of the lack of properly designed risk models and/or randomized studies. Although it has not been overwhelmingly shown that off-pump surgery is superior to the conventional on-pump procedure, the technique has its place in our specialty. It has been shown to be better for noncritical end points in selected patients in the hands of selected surgeons. That there are differences in surgical skill among surgeons is something we all know but rarely discuss in public. Until now, disparities in skill have been most salient with uncommon and extraordinarily challenging operations. Perhaps the off-pump procedure should be regarded as the “challenging” aspect of coronary artery bypass surgery, and self-restraint may need to remain in force if we are to continue to achieve the highest level of clinical excellence.

Equivalence of the Acute Cytokine Surge and Myocardial Injury after Coronary Artery Bypass Grafting with and without a Novel Extracorporeal Circulation System

Cardiopulmonary bypass (CPB) contributes to a morbidity-inducing systemic Inflammatory response after cardiac surgery. We compared this response in patients receiving coronary artery bypass grafting (CABG) with (CPB group; n = 7) or without (off-pump group; n = 8) the Minimal Extracorporeal Circulation (MECC®) system. Serum concentrations of tumour necrosis factor (TNF)-α, soluble TNF receptors, pro- and anti-inflammatory interleukins (ILs) and other myocardial injury markers were measured after anaesthetic induction, at 1 h, 4 h and 24 h after completing all anastomoses or serially. Soluble TNF receptor type I (sTNFRI) and IL-8 peaked early after CABG in both groups and did not decline. Serum sTNFRI was significantly higher in the CPB compared with the off-pump group at 1 h, whereas IL-8 was significantly lower in the CPB group throughout. The MECC® system, therefore, produces an equivalent acute cytokine response and degree of myocardial injury to off-pump CABG, and may be useful when CABG cannot be performed without CPB.

Leucocyte-depleted Blood Cardioplegia

The effect of the depletion of leucocytes from cardioplegic and initial myocardial reperfusion blood on the inflammatory response and myocardial protection in patients with unstable angina undergoing cardiopulmonary bypass (CPB) was studied. Patients were allocated randomly to a leucocyte-depleted (LD) group or a control group. The LD group received continuous retrograde LD isothermic blood cardioplegia and the control group received isothermic blood cardioplegia. Blood samples were collected at seven time-points before, during and after the procedure. Total leucocyte counts of cardioplegia blood in the LD group were significantly lower than in the control group, but systemic leucocyte and neutrophil counts after CPB did not differ between the groups. The levels of adhesion molecules, cytokines, elastase and malondialdehyde were significantly increased after CPB in both groups and reached peak values 2-6 h after surgery; no other significant differences were found. LD cardioplegia and myocardial reperfusion did not attenuate the endothelial and neutrophil-mediated components of the CPB-induced inflammatory response, which may lead to myocardial reperfusion injury.

Endothelial Cell Adhesion Molecules and Cardiopulmonary Bypass

Endothelial cell activation and the cell surface expression of adhesion molecules are considered to be crucial steps in the systemic inflammatory response to cardiopulmonary bypass. Endothelial cell adhesion molecules mediate the process of leukocyte adhesion to the endothelium and their subsequent transmigration and degranulation in the subendothelial tissues. The levels of soluble endothelial adhesion molecules in plasma have been used to draw conclusions regarding the cell surface expression of these molecules; the limitations of such studies are discussed. Inhibition of cell adhesion molecules may prevent the inflammatory condition caused by cardiopulmonary bypass and reperfusion injury. Further studies are needed to define the role of endothelial cell adhesion molecules in this inflammatory response.

Major comorbid disease processes associated with increased incidence of acute kidney injury

Acute kidney injury (AKI) is commonly seen amongst critically ill and hospitalized patients. Individuals with certain co-morbid diseases have an increased risk of developing AKI. Thus, recognizing the co-morbidities that predispose patients to AKI is important in AKI prevention and treatment. Some of the most common co-morbid disease processes that increase the risk of AKI are diabetes, cancer, cardiac surgery and human immunodeficiency virus (HIV) acquired immune deficiency syndrome (AIDS). This review article identifies the increased risk of acquiring AKI with given co-morbid diseases. Furthermore, the pathophysiological mechanisms underlying AKI in relation to co-morbid diseases are discussed to understand how the risk of acquiring AKI is increased. This paper reviews the effects of various co-morbid diseases including: Diabetes, cancer, cardiovascular disease and HIV AIDS, which all exhibit a significant increased risk of developing AKI. Amongst these co-morbid diseases, inflammation, the use of nephrotoxic agents, and hypoperfusion to the kidneys have been shown to be major pathological processes that predisposes individuals to AKI. The pathogenesis of kidney injury is complex, however, effective treatment of the co-morbid disease processes may reduce its risk. Therefore, improved management of co-morbid diseases may prevent some of the underlying pathology that contributes to the increased risk of developing AKI.

Acute Kidney Injury in Cardiac Surgery and Cardiac Intensive Care

Acute kidney injury (AKI) is a serious postoperative complication following cardiac surgery. Despite the incidence of AKI requiring temporary renal replacement therapy being low, it is nonetheless associated with high morbidity and mortality. Therefore, preventing AKI associated with cardiac surgery can dramatically improve outcomes in these patients. The pathogenesis of AKI is multifactorial and many attempts to prevent or treat renal injury have been met with limited success. In this article, we will discuss the incidence and risk factors for cardiac surgery associated AKI, including the pathophysiology, potential biomarkers of injury, and treatment modalities.

Reconciling the IPC and Two-Hit Models: Dissecting the Underlying Cellular and Molecular Mechanisms of Two Seemingly Opposing Frameworks

Inflammatory cascades and mechanisms are ubiquitous during host responses to various types of insult. Biological models and interventional strategies have been devised as an effort to better understand and modulate inflammation-driven injuries. Amongst those the two-hit model stands as a plausible and intuitive framework that explains some of the most frequent clinical outcomes seen in injuries like trauma and sepsis. This model states that a first hit serves as a priming event upon which sequential insults can build on, culminating on maladaptive inflammatory responses. On a different front, ischemic preconditioning (IPC) has risen to light as a readily applicable tool for modulating the inflammatory response to ischemia and reperfusion. The idea is that mild ischemic insults, either remote or local, can cause organs and tissues to be more resilient to further ischemic insults. This seemingly contradictory role that the two models attribute to a first inflammatory hit, as priming in the former and protective in the latter, has set these two theories on opposing corners of the literature. The present review tries to reconcile both models by showing that, rather than debunking each other, each framework offers unique insights in understanding and modulating inflammation-related injuries.

Interaction of MIF Family Proteins in Myocardial Ischemia/Reperfusion Damage and Their Influence on Clinical Outcome of Cardiac Surgery Patients

AIMS

Cardiac surgery involves myocardial ischemia/reperfusion (I/R) with potentially deleterious consequences. Macrophage migration inhibitory factor (MIF) is a stress-regulating chemokine-like cytokine that protects against I/R damage, but functional links with its homolog, d-dopachrome tautomerase (MIF-2), and the circulating soluble receptor CD74 (sCD74) are unknown. In this study, we investigate the role of MIF, MIF-2, sCD74, and MIF genotypes in patients scheduled for elective single or complex surgical procedures such as coronary artery bypass grafting or valve replacement.

RESULTS

MIF and MIF-2 levels significantly increased intraoperatively, whereas measured sCD74 decreased correspondingly. Circulating sCD74/MIF complexes were detectable in 50% of patients and enhanced MIF antioxidant activity. Intraoperative MIF levels were independently associated with a reduced risk for the development of atrial fibrillation (AF) (odds ratio 0.99 [0.98-1.00]; p=0.007). Circulating levels of MIF-2, but not MIF, were associated with an increased frequency of organ dysfunction and predicted the occurrence of AF (area under the curve [AUC]=0.663; p=0.041) and pneumonia (AUC=0.708; p=0.040). Patients with a high-expression MIF genotype exhibited a reduced incidence of organ dysfunction compared with patients with low-expression MIF genotypes (3 vs. 25; p=0.042).

INNOVATION

The current study comprehensively highlights the kinetics and clinical relevance of MIF family proteins and the MIF genotype in cardiac surgery patients.

CONCLUSION

Our findings suggest that increased MIF levels during cardiac surgery feature organ-protective properties during myocardial I/R, while the soluble MIF receptor, sCD74, may enhance MIF antioxidant activity. In contrast, high MIF-2 levels are predictive of the development of organ dysfunction. Importantly, we provide first evidence for a gene-phenotype relationship between variant MIF alleles and clinical outcome in cardiac surgery patients.

Minimized extracorporeal circulation is improving outcome of coronary artery bypass surgery in the elderly

Advanced age is a known risk factor for morbidity and mortality after coronary artery bypass grafting (CABG). Minimized extracorporeal circulation (MECC) has been shown to reduce the negative effects associated with conventional extracorporeal circulation (CECC). This trial assesses the impact of MECC on the outcome of elderly patients undergoing CABG. Eight hundred and seventy-five patients (mean age 78.35 years) underwent isolated CABG using CECC (n=345) or MECC (n=530). The MECC group had a significantly shorter extracorporeal circulation time (ECCT), cross-clamp time and reperfusion time and lower transfusion needs. Postoperatively, these patients required significantly less inotropic support, fewer blood transfusions, less postoperative hemodialysis and developed less delirium compared to CECC patients. In the MECC group, intensive care unit (ICU) stay was significantly shorter and 30-day mortality was significantly reduced [2.6% versus 7.8%; p<0.001]. In conclusion, MECC improves outcome in elderly patients undergoing CABG surgery.

Separation of mediastinal shed blood during aortic valve surgery elicits a reduced inflammatory response

AIMS

The detrimental effects of inflammation following cardiopulmonary bypass (CPB) could negatively affect the postoperative outcome in a specific subset of high-risk patients. We therefore investigated the impact of a CPB circuit (Admiral, Eurosets, Italy) that allows separation of intracavitary and mediastinal blood on the release of biochemical markers and clinical outcome when compared with a conventional circuit.

METHODS

Thirty patients undergoing aortic valve surgery were prospectively enrolled and assigned to Admiral group (Group 1, G1, n = 15) or conventional CPB group (Group 2, G2, n = 15). The Admiral oxygenator allows for a separate collection of mediastinal blood processed through a cell-saver before retransfusion. Clinical data and biochemical parameters were measured preoperatively, during CPB and at different time-points postoperatively.

RESULTS

Preoperative demographics, intraoperative data (as CPB and aortic cross-clamping time) and perioperative complications did not differ between groups. Inflammatory response was significantly decreased in G1, as assessed by means of D-dimer (G1 = 1332.3  ±  953.9 vs. G2 = 2791.9  ±  1740.7  ng/ml, P = 0.02), C-reactive protein (G1 = 169.1  ±  164.8 vs. G2 = 57.1  ±  39.3  mg/l, P = 0.04), interleukin-6 (G1 = 11.8  ± 12.5 vs. G2 = 26.5  ±  24.9  pg/ml, P = 0.02) and tumour necrosis factor-alpha (G1 = 29  ±  28.7 vs. G2 = 45.5  ±  23.6 pg/ml, P = 0.03).

CONCLUSION

Although no considerable difference was detected in terms of perioperative outcomes, the Admiral oxygenator did result in a significant reduction of inflammatory markers during the early postoperative course.

Dysfunction of alveolar macrophages after cardiac surgery and postoperative pneumonia?--An observational study

Introduction

Patients undergoing cardiac surgery have an increased risk of postoperative pneumonia. Pulmonary immune dysfunction might be a contributing factor. We therefore determined changes of the surface molecules on alveolar macrophages (AMs). To characterize modulation in patients with pneumonia we correlated these changes to the development of postoperative pneumonia.

Methods

After ethical approval and written informed consent, 33 patients undergoing elective coronary bypass grafting surgery were included in this observational study. Peripheral blood cells and alveolar lavage fluid were collected directly after induction of anesthesia and two hours after separation from cardiopulmonary bypass (CPB). Human leukocyte antigen-DR (HLA-DR) and toll-like receptors (TLR) 2/4 expression on monocytes and AM were assessed by flow cytometry. A total of three patients developed postoperative pneumonia determined according to the criteria of the Center of Disease Control. Statistical analysis was performed with the Mann–Whitney-U test and Wilcoxon test.

Results

We found significant changes of phenotypic and functional immune markers on AMs after cardiac surgery. HLA-DR expression on peripheral blood monocytes and AMs was significantly reduced compared to baseline in all patients (each approximately 30%). After surgery patients who developed postoperative pneumonia revealed a trend of stronger reduction of HLA-DR expression (83.7% versus 27.1%) and TLR4 expression on AMs (46.1% versus 9.9%) compared to patients without pneumonia. Already before surgery, the baseline of TLR2 expression on AM was significantly lower (27.7%) in patients who developed postoperative pneumonia.

Conclusions

As far as we know this is the first study that shows an early impairment of lung cellular immune response after cardiac surgery. These findings can help to understand the role of cell-mediated immunosuppression and its association to the development of postoperative pneumonia.

Temporal leukocyte numbers and granulocyte activation in pulsatile and rotary ventricular assist device patients

Individual ventricular assist device (VAD) design may affect leukocytes and impact immunity. Few studies have presented leukocyte and infection profiles in VAD patients over the course of the implant period. CD11b (MAC-1) expression on granulocytes is an indicator of activation during inflammation, mediating extravasation and the release of reactive oxygen species in tissue. No reported studies have presented MAC-1 expression on circulating granulocytes in VAD patients. Fifty-six patients implanted at a single center with a HeartMate II (HMII; n = 32), HeartWare (HW; n = 12), or Thoratec pneumatic VAD (PVAD; n = 12) between 1999 and 2011 were followed for 120 days of support. The leukocyte profiles and infectious events of all patients were evaluated; additionally, a subset had MAC-1 expression on circulating granulocytes was measured (HMII n = 9; HW n = 7; PVAD n = 4). All groups exhibited a significant peak in leukocyte numbers at postoperative day (POD) 14 while simultaneously experiencing a significant decrease in hematocrit. HMII patients exhibited a 3.2-fold increase in granulocyte MAC-1 expression at POD 14, and the temporal trend over the implant period differed from that experienced by HW patients. Further, HW patients experienced significantly fewer infection events. Alterations in leukocyte profiles and granulocyte activation experienced by VAD patients appear to be device-specific. Elevations in leukocyte activation may be related to an increased risk for infection, although the specific relationship between these phenomena in this patient group is not known.

CD62L (L-selectin) shedding for assessment of perioperative immune sensitivity in patients undergoing cardiac surgery with cardiopulmonary bypass

OBJECTIVE

To investigate the suitability of blood granulocyte and monocyte sensitivity, as measured by the quantity of different agonists required to induce CD62L shedding, for assessment of perioperative immune changes in patients undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

Patients scheduled for aortocoronary bypass grafting or for valve surgery were included in this prospective observational study. Blood samples were drawn before anesthesia induction, directly after surgery and 48 hours after anesthesia induction. We determined the concentration of two different inflammatory stimuli--lipoteichoic acid (LTA) and tumor necrosis factor alpha (TNF)--required to induce shedding of 50% of surface CD62L from blood granulocytes and monocytes. In parallel monocyte surface human leukocyte antigen (HLA)-DR, and plasma interleukin (IL)-8, soluble (s)CD62L, soluble (s)Toll-like receptor (TLR)-2 and ADAM17 quantification were used to illustrate perioperative immunomodulation.

RESULTS

25 patients were enrolled. Blood granulocytes and monocytes showed decreased sensitivity to the TLR 2/6 agonist Staphylococcus aureus LTA immediately after surgery (p = 0.001 and p = 0.004 respectively). In contrast, granulocytes (p = 0.01), but not monocytes (p = 0.057) displayed a decreased postoperative sensitivity to TNF. We confirmed the presence of a systemic inflammatory response and a decreased immune sensitivity in the post-surgical period by measuring significant increases in the perioperative plasma concentration of IL-8 (p ≤ 0.001) and sTLR (p = 0.004), and decreases in monocyte HLA-DR (p<0.001), plasma sCD62L (p ≤ 0.001). In contrast, ADAM17 plasma levels did not show significant differences over the observation period (p = 0.401).

CONCLUSIONS

Monitoring granulocyte and monocyte sensitivity using the "CD62L shedding assay" in the perioperative period in cardiac surgical patients treated with the use of cardiopulmonary bypass reveals common changes in sensitivity to TLR2/6 ligands and to TNF stimulus. Further long-term follow-up studies will address the predictive value of these observations for clinical purposes.

Phase 1 study of two inodilators in neonates undergoing cardiovascular surgery

BACKGROUND

Inodilators are routinely used in cardiovascular surgery with cardiopulmonary bypass (CPB). Information regarding safety and tolerability of the novel molecule, levosimendan (LEVO), in newborns is anecdotal; no pharmacokinetic data in this population are available.

METHODS

This was a phase I, randomized, and blinded study. Neonates undergoing surgical repair for congenital heart defects received stepwise dose increases of milrinone (MR; 0.5-1 μg/kg/min, n = 9) or LEVO (0.1-0.2 μg/kg/min, n = 11) as an i.v. continuous infusion, starting before CPB. Infants had continuous, time-locked, physiological, and near-infrared spectroscopy (NIRS) (cerebral and peripheral) recordings during the first 24 h, and at 48 and 96 h postsurgery. Serial biochemistry and pharmacokinetic studies were performed.

RESULTS

During the first 24 h postsurgery, patients showed time-related, group-independent increased cerebral tissue oxygenation and decreased diastolic blood pressure; in addition, group-dependent differences in heart rate and peripheral perfusion were found. Early postsurgery, MR-treated infants showed lower pH, higher glycemia, and higher inotrope score. The groups differed in cerebral NIRS-derived variables from 24 to 96 h. Study drug withdrawal at 96 h was more frequent with LEVO. LEVO intermediate metabolites were detected in plasma at day 14 after surgery.

CONCLUSION

LEVO is well tolerated in critically ill neonates. LEVO may have advantages over MR in terms of the dosing regimen.

[Results of coronary artery bypass grafting with left ventricular dysfunction (comparison of off-pump versus on-pump)]

BACKGROUND

The aim of this study was to compare the results of myocardial revascularisation with or without cardiopulmonary bypass in patients with impaired left ventricular function.

PATIENTS AND METHODS

Five hundred and sixteen consecutive patients who underwent coronary artery bypass grafting from January 2000 through December 2007 were analyzed retrospectively. One hundred and eight cases had a left ventricular EF (ejection fraction) of 45% or less. Of these patients, 78 underwent conventional coronary artery bypass (CCABG) and 30 underwent off-pump procedure (OCABG). The CCABG group received 300IU/kg of heparin while the OCABG received 100IU/kg. The off-pump coronary surgery was carried out using a tissue stabilizer Octopus II. Different pre-, per- and postoperative variables were evaluated among both groups. Statistical analysis was performed by SPSS 11.5. The variables were compared between these two groups using univariate analysis (Chi(2) test, Fisher's test exact) for qualitative variable and (Student's t test, Mann-Whitney's test) for quantitative variable.

RESULTS

Patients profiles and risk factors were similar among both groups except for age (CCABG: 57.8±9.2 year vs OCABG: 52±9.9 year; P=0.004) and left ventricular EF (CCABG: 37.4±6.3% vs OCABG: 34±7.8%; P=0.02). The number of grafts performed per patient was significantly more among patients who underwent extracorporeal circulation (CCABG: 2.53±0.7 graft/patient vs OCABG: 1.77±0.8 graft/patient; P<0.0001). The hospital mortality was more among CCABG group 9% vs 3.3% in OCABG but the difference was not significant (P=0.3). However, the operative time and the operative room stay were long in CCABG (252±61min vs 175±38min; P<0.0001 - 389±70min vs 298±54min; P<0.0001). The ventilation time was also long in CCABG (32.3±67hour vs 10.4±5.9hour; P=0.15). There was more postoperative myocardial infarction in CCABG (P=0.008), but the EF increased and was better in CCABG.

CONCLUSION

Off-pump coronary artery bypass surgery provides satisfactory operative results for most patients with reduced left ventricular function. Prospective and randomly study will be necessary before concluding.

A comparative study of the immune modulating properties of antifibrinolytics in cardiac surgery

PURPOSE

Antifibrinolytics, used in cardiac surgery to abate postoperative blood loss, share anti-inflammatory properties by suppression of pro-inflammatory D-dimer and plasmin levels. Additional drug specific immune modulating qualities are often mentioned in the discussion on which antifibrinolytic can best be used. To determine the extent and relevance of these effects, we investigated cytokine and growth factor plasma levels in cardiac surgery patients randomized to receive either tranexamic acid, aprotinin, or placebo. Corticosteroid-treated patients served to put the effects in perspective.

METHODS

Using a biochip immunoassay, plasma of 36 cardiac surgery patients was quantified for 12 cytokines and growth factors, assessed preoperatively and 6, 12, 24, and 48 h after the start of cardiopulmonary bypass. Eight patients were treated with tranexamic acid, nine with aprotinin, and nine received placebo. Ten placebo-treated patients received corticosteroids.

RESULTS

IL-1ß, IL-6, IL-8, IL-10, IFN-γ, TNF-α, VEGF, MCP-1, and EGF plasma concentrations significantly changed over time across all patients. Aprotinin-treated patients showed decreased pro-inflammatory TNF-α and peak MCP-1 plasma levels when compared with placebo. However, corticosteroids attenuated the inflammatory response to a much larger extent, lowering postoperative IL-6, IL-10, IFN-γ, and VEGF concentrations also.

CONCLUSIONS

Aprotinin attenuates postoperative pro-inflammatory levels TNF-α and MCP-1 whereas tranexamic acid does not. The majority of plasma proteins studied, however, were not affected by the use of antifibrinolytics when compared with placebo. A clinically relevant common anti-inflammatory effect through inhibition of fibrinolysis seems therefore unlikely.

Successful coronary artery bypass grafting with the aid of a portable minimized extracorporeal life support system

Extracorporeal life support system has been successfully used in patients with cardiac failure after open heart surgery, as a bridge to transplantation, and in patients with prolonged cardiogenic shock or cardiopulmonary arrest. This report presents our early experience with the new system Cardiohelp in coronary artery bypass grafting (CABG). Between August 2010 and June 2011, 50 patients underwent CABG with the aid of Cardiohelp. This subgroup was matched for sex and logistic EuroSCORE with 100 patients, who underwent CABG using two different extracorporeal circulation systems, a minimized (MECC) (n = 50) and a conventional (CECC) (n = 50) during the same period. Because of less hemodilution, the intraoperative blood transfusion was significantly lower in the Cardiohelp group (36%) and MECC group (40%) compared with the CECC group (64%). Postoperative release of creatinine kinase and lactate was lower in the Cardiohelp and MECC groups (p < 0.001). Furthermore, these patients had shorter duration of ventilation and lengths of stay at the intensive care unit (p < 0.05). Device-related complications were not observed. A conversion to CECC was not necessary. In conclusion, the Cardiohelp is a safe alternative for CABG surgery. Valid technical innovations and limited number of side effects support its employment as a highly effective device for coronary surgery.

Cardiopulmonary bypass during cardiac surgery modulates systemic inflammation by affecting different steps of the leukocyte recruitment cascade

Background

It is known that the use of a cardiopulmonary bypass (CPB) during cardiac surgery leads to leukocyte activation and may, among other causes, induce organ dysfunction due to increased leukocyte recruitment into different organs. Leukocyte extravasation occurs in a cascade-like fashion, including capturing, rolling, adhesion, and transmigration. However, the molecular mechanisms of increased leukocyte recruitment caused by CPB are not known. This clinical study was undertaken in order to investigate which steps of the leukocyte recruitment cascade are affected by the systemic inflammation during CPB.

Methods

We investigated the effects of CPB on the different steps of the leukocyte recruitment cascade in whole blood from healthy volunteers (n = 9) and patients undergoing cardiac surgery with the use of cardiopulmonary bypass (n = 7) or in off-pump coronary artery bypass-technique (OPCAB, n = 9) by using flow chamber experiments, transmigration assays, and biochemical analysis.

Results

CPB abrogated selectin-induced slow leukocyte rolling on E-selectin/ICAM-1 and P-selectin/ICAM-1. In contrast, chemokine-induced arrest and transmigration was significantly increased by CPB. Mechanistically, the abolishment of slow leukocyte rolling was due to disturbances in intracellular signaling with reduced phosphorylation of phospholipase C (PLC) γ2, Akt, and p38 MAP kinase. Furthermore, CPB induced an elevated transmigration which was caused by upregulation of Mac-1 on neutrophils.

Conclusion

These data suggest that CPB abrogates selectin-mediated slow leukocyte rolling by disturbing intracellular signaling, but that the clinically observed increased leukocyte recruitment caused by CPB is due to increased chemokine-induced arrest and transmigration. A better understanding of the underlying molecular mechanisms causing systemic inflammation after CPB may aid in the development of new therapeutic approaches.

Coronary artery bypass grafting in patients with type 2 diabetes mellitus: a comparison between minimized and conventional extracorporeal circulation

Diabetes mellitus (DM) is an established independent risk factor for significant morbidity and mortality after coronary artery bypass grafting (CABG). The minimized extracorporeal circulation (MECC) allows a reduction of the negative effects associated with conventional extracorporeal circulation (CECC). In this study, the impact of the MECC on outcome of diabetic patients after CABG was assessed. Between January 2002 and December 2009, 1,184 patients with DM underwent elective isolated CABG using CECC (54.6%) or MECC (45.4%). All analysis was performed retrospectively. The extracorporeal circulation time was significantly reduced during MECC procedure. The postoperative increase of creatine kinase and lactate levels was significantly weaker in the MECC group (p < 0.001). Also, the transfusion requirements were significantly lower (p < 0.001). Furthermore, MECC patients had lower incidences of postoperative acute renal failure and sternal wound infections and shorter ICU and hospital lengths of stay (p < 0.05). Moreover, 30-day mortality was significantly reduced in the MECC group (p < 0.05). In conclusion, CABG surgery using MECC system is a safe alternative in patients with DM. A reduced postoperative mortality and lengths of stay, lower transfusion requirements, less renal and myocardial damage, and lower incidence of sternal wound infections encourage the usage of MECC system, especially in high-risk patients.

DEHP and its active metabolites: leaching from different tubing types, impact on proinflammatory cytokines and adhesion molecule expression. Is there a subsumable context?

Introduction: Di(2-ethylhexyl)phthalate (DEHP) is suspected to be toxic for several reasons. During contact with a lipophilic medium, DEHP leaks from polyvinylchloride (PVC), but its influence on inflammatory reactions remains unknown. We examined specific DEHP leaching out of different tubing types, the possibly modulated liberation of proinflammatory cytokines and the induction of adhesion molecule expression in primary endothelial cells.

Materials and Methods: Blood samples were circulated in traditional PVC, nodioctyl phthalate (DOP) PVC and heparin-coated PVC tubing within a Chandler loop model. The blood was tested for the concentration of DEHP and its active metabolites as well as the liberation of the proinflammatory cytokines TNFα and IL1ß. Furthermore, we exposed human endothelial cells to circulated blood and analysed them for the expression of the adhesion molecules ICAM-1, VCAM-1 and E-selectin.

Results: In contrast to the other tubing, PVC tubing showed significantly elevated DEHP levels, but no alteration was observed concerning a potential up-regulation of the cytokines or activation of the endothelial adhesion molecule receptors.

Conclusions: Our data conclude that there is no correlation between DEHP leaching and the inflammatory response after ECC support, but this study showed that even DEHP-free material is leaching DEHP and its toxic metabolites.

Beneficial effects of using a minimal extracorporeal circulation system during coronary artery bypass grafting

Background: In this study, we assessed clinical results by using a minimal extracorporeal circuit (MECC) and compared it to a conventional cardiopulmonary bypass (CPB) system in patients undergoing coronary artery bypass grafting (CABG) procedures.

Methods and Materials: From August to October 2006, forty consecutive patients undergoing isolated CABG procedures were randomly assigned to either a miniaturized closed circuit CPB with the Maquet-Cardiopulmonary MECC system (Group M, n=20) or to a conventional CPB system (Group C, n=20). Clinical outcomes were observed before, during and after the operation. Besides evaluating the perioperative clinical data, serial blood venous samples were obtained after induction, 30 minutes after CPB initiation, 2h, 6h, 12h, and 24h post-CPB. The focus of our study was on myocardial damage (cTnI), neutrophil and platelet counts, activated partial thromboplastin time (aPTT) and free hemoglobin.

Results: Both the transfusion of packed red blood cells and fresh frozen plasma were significantly lower in Group M compared to Group C ( p<0.05). The levels of cTnI were lower in Group M at 2h, 6h and 12h post-CPB than in Group C ( p<0.01). The values of aPTT in Group M recovered to normal levels after surgery, but were prolonged in Group C at early post-CPB and were statistically longer than Group M at 2h, 6h, and 12h post-CPB ( p<0.05). The concentrations of free hemoglobin in Group C were higher than in Group M during and post-CPB, and there was a statistical difference at 2h post-CPB ( p<0.05).

Conclusion: In conclusion, the MECC system is a safe alternative for patients who undertake extracorporeal circulation (ECC) for CABG surgery. Lower transfusion requirements and less damage to red cells may further promote the use of MECC systems, especially in higher risk patients.

Systemic vascular cell adhesion molecule-1 predicts the occurrence of post-operative atrial fibrillation

BACKGROUND

Post-operative atrial fibrillation occurs in 30% of patients after on-pump heart surgery and is associated to elevated inflammatory markers. We have evaluated if the systemic biomarkers of inflammation and endothelial damage, vascular cell adhesion molecule-1 (VCAM-1) and soluble thrombomodulin may help in identifying patients prone to development of post-operative atrial fibrillation.

METHODS

One hundred and forty-four patients in sinus rhythm submitted to elective coronary artery bypass surgery. Systemic inflammatory, oxidative stress and endothelial damage markers were measured at baseline and 72 h after surgery. During the procedure, a sample of the right atrial appendage was obtained for histochemistry. Electrocardiogram was monitored for 72 h after surgery for event adjudication.

RESULTS

22% of the patients developed post-operative atrial fibrillation. Baseline systemic inflammatory markers did not differ between patients with or without post-operative atrial fibrillation. However, baseline plasma VCAM-1 and thrombomodulin levels were significantly higher in patients who developed post-operative atrial fibrillation. After adjustment for age, gender, comorbidities and concurrent medication, circulating VCAM-1 remained as an independent predictor for post-operative atrial fibrillation development. No association was observed between systemic plasma VCAM-1 and VCAM-1 tissue expression in the right atrial appendage.

CONCLUSIONS

In patients undergoing coronary artery bypass surgery, elevated VCAM-1 levels predict a higher risk for post-operative atrial fibrillation. Plasma VCAM-1 elevation is not related to its expression in the right atria, suggesting that systemic endothelial damage rather than local changes pre-exist in patients who develop the arrhythmia.

Relocalization of Endothelial Cell β-Catenin After Coculture With Activated Neutrophils From Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with neutrophil activation, inflammation, and consecutive edema. The impairment of endothelial junction molecules, and thus, hyperpermeability elicited by the interaction of activated neutrophils with endothelial cells may be important in this regard. Cocultures with human endothelial cells and neutrophils from 10 cardiac surgery patients with CPB were used to evaluate the role of neutrophils in modifications of the endothelial zonula adherens molecules VE-cadherin and beta-catenin. Laser scan microscopic analyses showed that neutrophils, which were isolated after the beginning of CPB, significantly impaired intracellular redistribution of endothelial beta-catenin with regard to membrane association (p <.0002) and staining pattern (p <.0001). VE-cadherin localization was not found to be significantly modified. Western blots with total cell extracts showed that amounts of beta-catenin did not vary significantly after co-culture with activated neutrophils. Activated neutrophils during cardiac surgery with CPB may induce endothelial dysfunction by impairing beta-catenin localization and thus contribute to endothelial hyperpermeability.

Cardiac Surgery With Extracorporeal Circulation: Neutrophil Transendothelial Migration Is Mediated by β1 Integrin (CD29) in the Presence of TNF-Alpha

Cardiac surgery with extracorporeal circulation is associated with neutrophil activation, inflammation, and edema. Endothelial hyperpermeability elicited by the interaction of activated neutrophils and/or cytokines with endothelial cells may be critical in this regard. However, the immune and cellular mechanisms involved are not fully understood. Cocultures with human endothelial cells and neutrophils from cardiac surgery patients were used to evaluate the role of beta1 integrin activity and the proinflammatory cytokine tumor necrosis factor (TNF)-alpha in neutrophil transendothelial migration and in impairment of the integrity of endothelial cell-to-cell contacts. Blocking of CD29 (heavy chain of beta1 integrins) totally prevented neutrophil adhesion and transendothelial migration. Pretreatment of neutrophils with either a CD29-stimulating monoclonal antibody or the addition of TNF-alpha (0.1-10 U/ml) to the coculture failed to induce transendothelial migration. However, coculture of endothelial cells with CD29-stimulated neutrophils in the presence of 0.1-10 U/ml TNF-alpha strongly induced neutrophil transmigration. CD29/TNF-alpha-mediated transmigration was associated with intracellular redistribution of endothelial beta-catenin. We further showed that CD29/TNF-alpha-mediated effects involved PI3K and tyrosine kinase-dependent signaling via MAPK but were independent of nuclear transcription factor (NF)-kappaB activity. Inhibition of CD29/TNF-alpha might be a therapeutic option to limit endothelial dysfunction following cardiac surgery with extracorporeal circulation.

Aortic valve replacement with minimal extracorporeal circulation versus standard cardiopulmonary bypass

The purpose of this study was to evaluate the safety and the clinical outcomes of aortic valve replacement (AVR) performed with minimally invasive extracorporeal circulation (miniECC) technique vs. standard cardiopulmonary bypass (CPB). From February 2006 to December 2007 a total of 181 isolated AVR were performed, of these 53 patients were operated using minimal extracorporeal circulation system and 128 patients were operated using the standard CPB. Demographic characteristics and operative data were similar in both groups except for EuroSCORE (P<0.0001). Operative mortality (<30 days) was 3.8% for miniECC group and 4.7% for CPB group (P=ns). Patients in both groups showed similar postoperative chest tube drainage (432+/-325 ml vs. 460+/-331 ml, P=ns). The percentage of transfused patients was similar in both groups (37.7% vs. 43.8%, P=0.45). The number of transfused blood bank products was higher in patients with a body surface area >1.7 m(2) and who underwent traditional CPB in respect to miniECC system. Postoperatively renal injury, atrial fibrillation episodes, neurologic event rate, ICU and hospital stay length were similar in both groups. The miniECC is suitable for AVR providing good clinical results but the present results should not identify the miniECC system to be superior to the conventional CPB.

Minimal extracorporeal circulation: an alternative for on-pump and off-pump coronary revascularization

BACKGROUND

Coronary artery bypass surgery employing minimal extracorporeal circulation (MECC) was compared with standard extracorporeal circulation (ECC) and off-pump coronary artery bypass graft surgery (OPCABG) with regard to the perioperative course.

METHODS

From January 2004 to December 2007, 1,674 patients (n = 558 MECC, n = 558 ECC, n = 558 OPCABG) who underwent coronary bypass surgery were studied. The primary end point was in-hospital mortality; secondary end points were perioperative variables, intensive care, and in-hospital course.

RESULTS

Demographic data, comorbidity, and the European System for Cardiac Operative Risk Evaluation score (MECC 3.0%, ECC 3.5%, OPCABG 3.2%) were similar among the groups, but in-hospital mortality for elective and urgent/emergent patients was lower in the MECC and OPCABG groups (MECC 3.2%, OPCABG 3.7%, ECC 6.9%; p < 0.05). The number of distal anastomoses was lowest in the OPCABG group, but comparable for MECC and ECC patients. Postoperative ventilation time, release of creatinine kinase, catecholamine therapy, drainage loss, and transfusion requirements were lower in the MECC and OPCABG groups, whereas stay in the intensive care unit was shorter only in the latter (p < 0.05).

CONCLUSIONS

Minimal extracorporeal circulation is an easy and safe procedure for coronary artery bypass graft surgery. In selected patients, the advantages of MECC equal those of OPCABG. MECC should be considered as an alternative to OPCABG and standard ECC procedures.

Association of circulating adhesion molecules with lung function. The CARDIA study

BACKGROUND

Systemic inflammation has been associated with reduced lung function. Adhesion molecules, such as intercellular adhesion molecule (ICAM)-1 and P-selectin, figure importantly in initiating the inflammatory response. We studied the association between ICAM-1 and P-selectin concentrations and lung function in the Coronary Artery Risk Development in Young Adults study.

METHODS

Spirometry testing was conducted at years 5, 10, and 20. ICAM-1 and P-selectin were assayed at year 15.

RESULTS

Complete data were obtained from 2,455 participants. We first predicted year-20 lung function from year-15 ICAM-1 concentration data. After controlling for race, gender, height, age, physical activity, smoking status, alcohol intake, BMI, and asthma status, all taken at year 15, the year-20 FVC was 164 mL higher (p < 0.0001) and FEV(1) was 164 mL higher (p = 0.0003) in the lowest ICAM-1 concentration quartile than the highest ICAM-1 quartile, whereas the FEV(1)/FVC ratio showed no association (p = 0.25). We then predicted the year-15 ICAM-1 concentration from year-5 lung function and change in lung function (year 10 - year 5). The year-15 ICAM-1 concentration was about 13 ng/mL higher in the lowest vs highest quartile of either the year-5 FVC (p = 0.01) or year-5 FEV(1) (p = 0.005). Year-15 ICAM-1 concentration was unrelated to year-5 FEV(1)/FVC ratio. Greater loss in FVC and FEV(1) (year 10 - year 5) also was associated with higher year-15 ICAM-1 concentrations. Associations between P-selectin and lung function followed a similar but weaker pattern to that observed for ICAM-1.

CONCLUSIONS

These data suggest a bidirectional association between circulating adhesion molecules, such as ICAM-1 and P-selectin, and pattern of lung function change in adults.

The role of inflammation in atrial fibrillation following open heart surgery

This study investigated the role of systemic inflammation in the development of atrial fibrillation (AF) after coronary artery bypass grafting (CABG). CABG was performed using cardiopulmonary bypass in 77 patients. Pre-operative AF was present in six patients (7.8%) and postoperative AF developed in 13 (18.3%) of the 71 patients with pre-operative sinus rhythm. Post-operative mediastinal drainage was significantly increased in patients with post-operative AF compared with those with sinus rhythm. Plasma E-selectin, P-selectin and vascular cell adhesion molecule levels were not significantly different between patients with pre- and post-operative sinus rhythm, those with pre-operative sinus rhythm and post-operative AF, and those with pre- and post-operative AF. There were significant differences between pre- and post-operative C-reactive protein, interleukin (IL)-6 and IL-10 levels within all three groups, but no differences in these parameters between the groups. Thus, in all groups there were significant alterations in mediators indicative of systemic inflammation following CABG, but comparisons between the groups revealed no differences predictive of AF.

Inhibition of adhesion molecule expression on human venous endothelial cells by non-viral siRNA transfection

Objective: Expression of adhesion molecule receptors on venous endothelial cells crucially influences the fate of venous grafts by mediating leukocyte-endothelium interactions. These interactions include adhesion of leukocytes to the endothelium, followed by transendothelial migration, leading to neointimal hyperplasia and finally graft occlusion. Therefore, inhibition of adhesion molecule expression may be a promising strategy to improve the quality of venous grafts. We tested the efficiency of non-viral transfection of human venous endothelial cells with short interfering RNA (siRNA) to specificially down-regulate adhesion molecule expression. Methods: Primary cultures of human venous endothelial cells (HVEC) were examined for expression of the adhesion molecules ICAM1, VCAM1 and E-selectin (SELE) after non viral siRNA transfection. Adhesion molecule expression was measured by flow cytometry, real-time PCR and immunoblotting after stimulation with TNF-alpha, an inflammatory cytokine. Results: Non-transfected cells showed a strong increase of adhesion molecule expression following cytokine stimulation (p<0.01). Upon transfection with specific siRNAs a six fold decrease in ICAM1 (p<0.001) and SELE expression and cell positivity (p<0.05) and a twofold decrease in VCAM1 expression and cell positivity (p<0.01) could be observed. SiRNA-mediated gene suppression of adhesion molecules was also reflected by corresponding decreases in adhesion protein and transcript levels. Conclusions: The expression of adhesion molecules on HVECs can be effectively inhibited by specific siRNAs using a safe, non-viral transfection approach. This is a promising tool to precondition venous bypass grafts in order to interfere with endothelium-leukocyte interactions and to prohibit neointima thickening or atherosclerosis, which are regarded to be the most important causes of venous graft failure.