Inflammatory response to cardiopulmonary bypass: mechanisms involved and possible therapeutic strategies

Heparin molecularly imprinted surfaces for the attenuation of complement activation in blood

Heparin molecularly imprinted polymer films limit complement activation in whole blood.

Selenium and coenzyme Q10 interrelationship in cardiovascular diseases--A clinician's point of view

A short review is given of the potential role of selenium deficiency and selenium intervention trials in atherosclerotic heart disease. Selenium is an essential constituent of several proteins, including the glutathione peroxidases and selenoprotein P. The selenium intake in Europe is generally in the lower margin of recommendations from authorities. Segments of populations in Europe may thus have a deficient intake that may be presented by a deficient anti-oxidative capacity in various illnesses, in particular atherosclerotic disease, and this may influence the prognosis of the disease. Ischemic heart disease and heart failure are two conditions where increased oxidative stress has been convincingly demonstrated. Some of the intervention studies of anti-oxidative substances that have focused on selenium are discussed in this review. The interrelationship between selenium and coenzyme Q10, another anti-oxidant, is presented, pointing to a theoretical advantage in using both substances in an intervention if there are deficiencies within the population. Clinical results from an intervention study using both selenium and coenzyme Q10 in an elderly population are discussed, where reduction in cardiovascular mortality, a better cardiac function according to echocardiography, and finally a lower concentration of the biomarker NT-proBNP as a sign of lower myocardial wall tension could be seen in those on active treatment, compared to placebo.

Intraoperative ventilation strategy during cardiopulmonary bypass attenuates the release of matrix metalloproteinases and improves oxygenation

BACKGROUND

Patients undergoing open heart surgery with cardiopulmonary bypass (CPB) often develop a systemic immune reaction, characterized by an increase of proinflammatory and anti-inflammatory mediators. We previously demonstrated that continued mechanical ventilation during CPB reduces this response. We hypothesized that this strategy may also impact on matrix metalloproteinase (MMP) release.

MATERIAL AND METHODS

Thirty consecutive patients undergoing coronary artery bypass grafting with CPB were randomized into a ventilated (VG) (n = 15) and a standard non-ventilated group (NVG) (n = 15). Blood was collected at the beginning, at the end of surgery, and on the five consecutive days. MMPs, tissue inhibitor of matrix metalloproteinase 1 (TIMP-1), and lipocalin 2 (LCN2) were measured by enzyme-linked immunosorbent assay. Parameters of transpulmonary oxygen transport were assessed at different time points.

RESULTS

MMP-8, MMP-9, and LCN2 were significantly lower at the end of surgery in VG compared with those in NVG patients (MMP-8 [ng/mL]: 7.1 [3.5] versus 12.5 [7.7], P = 0.02; MMP-9 [ng/mL]: 108 [42] versus 171 [98], P = 0.029; LCN2 [ng/mL]: 109 [42] versus 171 [98], P = 0.03). TIMP-1 concentrations were lower on postoperative day one, (TIMP-1 [ng/mL]: 174 [55] versus 273 [104], P = 0.003), whereas MMP-3 levels were lower on postoperative days four and five (MMP-3 [ng/mL]: 44 [17] versus 67 [35], P = 0.026). The arterial partial pressure of oxygen/fraction of inspired oxygen ratio was significantly higher in VG patients throughout the postoperative observation period, which did not affect the length of postoperative ventilatory support.

CONCLUSIONS

Continued mechanical ventilation during CPB reduces serum levels of MMPs, their inhibitor TIMP-1 and LCN2, which preserves MMP-9 activity. The present study suggests that continued mechanical ventilation improves postoperative oxygenation and could potentially prevent aggravation of lung injury after CPB.

Outcomes of intraoperative venoarterial extracorporeal membrane oxygenation versus cardiopulmonary bypass during lung transplantation

BACKGROUND

The intraoperative use of cardiopulmonary bypass (CPB) in lung transplantation has been associated with increased rates of pulmonary dysfunction and bleeding complications. More recently, extracorporeal membrane oxygenation (ECMO) has emerged as a valid alternative method of support and has been our preferred method of support since March 2012. We compared early and midterm outcomes of these 2 support methods.

METHODS

Between July 2007 and April 2013, 271 consecutive patients underwent lung transplant using CPB (n = 222) or ECMO (n = 49). We retrospectively reviewed the outcomes of these patients requiring CPB or ECMO during lung transplant.

RESULTS

The CPB and ECMO groups had comparable demographic and operative characteristics; however, the ECMO group had higher mean lung allocation scores (73 vs 52, p < 0.001). In the CPB group, more patients required reintubation (35.6% vs 20.4%, p = 0.04) or temporary tracheostomy (44.6% vs 28.6%, p = 0.05). Patients in the CPB group had a higher rate of renal failure requiring dialysis than the ECMO group (22.1% vs 8.2 %, p = 0.028). There were no differences in severe PGD requiring postoperative circulatory support (p = 0.83) or the need for perioperative red blood cell transfusions (p = 0.64) between the groups. No differences in 30-day (5% CPB vs 4.1% ECMO) or 6-month mortality (14.4% CPB vs 14.3% ECMO) were noted.

CONCLUSIONS

The use of ECMO in lung transplant is safe and in our experience was associated with decreased rates of pulmonary and renal complications, as compared with CPB. Extracorporeal membrane oxygenation has become our preferred method of intraoperative support during lung transplantation.

Innovative approaches in the perioperative care of the cardiac surgical patient in the operating room and intensive care unit

Perioperative care for cardiac surgery is undergoing rapid evolution. Many of the changes involve the application of novel technologies to tackle common challenges in optimizing perioperative management. Herein, we illustrate recent advances in perioperative management by focusing on a number of novel components that we judge to be particularly important. These include: the introduction of brain and somatic oximetry; transesophageal echocardiographic hemodynamic monitoring and bedside focused ultrasound; ultrasound-guided vascular access; point-of-care coagulation surveillance; right ventricular pressure monitoring; novel inhaled treatment for right ventricular failure; new approaches for postoperative pain management; novel approaches in specialized care procedures to ensure quality control; and specific approaches to optimize the management for postoperative cardiac arrest. Herein, we discuss the reasons that each of these components are particularly important in improving perioperative care, describe how they can be addressed, and their impact in the care of patients who undergo cardiac surgery.

The Effect of Pulsatile Cardiopulmonary Bypass on Lung Function in Elderly Patients

Purpose

Cardiopulmonary bypass is still a major cause of lung injury and delay in pulmonary recovery after cardiac surgery. Although it has been shown that pulsatile flow induced by intra-aortic balloon pumping is beneficial for preserving lung function, it is not clear if the same beneficial effect can be accomplished with pulsatile flow generated in the extracorporeal circuit. Therefore, we investigated the effect of pulsatile flow, produced by a centrifugal pump, on lung function in elderly patients.

Methods

Serial measurements of lung biomarkers Clara cell 16 kD protein, surfactant protein D, and elastase were performed on blood samples from 37 elderly patients (≥75 years) who underwent elective aortic valve replacement surgery with CPB, either with pulsatile perfusion or continuous perfusion. Pulmonary function was assessed by postoperative ventilation time, the arterial blood oxygenation (PaO2/FiO2), the alveolar-arterial oxygen gradient (Aa-O2 gradient) and the pulmonary vascular resistance indexed by body surface area (PVRi).

Results

There was no difference in lung function between both groups, as assessed by the postoperative ventilation time, the PaO2/FiO2 ratio, and the Aa-O2 gradient. The PVRi, however, was significantly lower in the pulsatile perfusion group 15 mins after the administration of protamine (p<0.05). The plasma concentrations of the lung biomarkers increased during surgery and peaked at 1 h ICU, there were however no differences between groups.

Conclusions

Pulsatile flow does not seem beneficial to postoperative lung function in elderly patients. Moreover, pulsatile flow does not affect lung function on a subclinical level as assessed by lung biomarkers.

Alpha lipoic acid attenuates inflammatory response during extracorporeal circulation

Aim

Extracorporeal circulation (ECC) of blood during cardiopulmonary surgery has been shown to stimulate various pro-inflammatory molecules such as cytokines and chemokines. The biochemical oxidation/reduction pathways of a-lipoic acid suggest that it may have antioxidant properties.

Methods

In this study we aimed to evaluate only patients with coronary heart disease and those planned for coronary artery bypass graft operation. Blood samples were obtained from the patients before the operation (P1) and one (P2), four (P3), 24 (P4) and 48 hours (P5) after administration of a-lipoic acid (LA). The patients were divided into two groups, control and LA treatment group. Levels of interleukin-6 (IL-6) and -8 (IL-8), complement 3 (C3) and 4 (C4), anti-streptolysin (ASO), C-reactive protein (CRP) and haptoglobin were assessed in the blood samples.

Results

Cytokine IL-6 and IL-8 levels were significantly higher after surgery. Compared with the control groups, LA significantly decreased IL-6 and IL-8 levels in a time-dependent manner. CRP levels did not show significant variation in the first three time periods. CRP levels were higher after surgery, especially in the later periods. These results demonstrate that CRP formation depends on cytokine release. C3 and C4 levels were significantly higher after surgery than in the pre-operative period. LA treatment decreased C3 and C4 levels. Therefore, LA administration may be useful for the treatment of diseases and processes where excessive cytokine release could cause oxidative damage.

Conclusions

Our findings suggest a possible benefit of using LA during cardiac surgery to reduce cytokine levels.

Dexamethasone for the prevention of postpericardiotomy syndrome: A DExamethasone for Cardiac Surgery substudy

BACKGROUND

The postpericardiotomy syndrome (PPS) is a common complication following cardiac surgery. The pathophysiology remains unclear, although evidence exists that surgical trauma and the use of cardiopulmonary bypass provoke an immune response leading to PPS. We hypothesized that an intraoperative dose of dexamethasone decreases the risk of PPS, by reducing this inflammatory response.

METHODS

We performed a subanalysis of the DECS study, which is a multicenter, double-blind, placebo-controlled, randomized trial of 4,494 patients undergoing cardiac surgery with use of cardiopulmonary bypass. The aim of the DECS study was to investigate whether a single intraoperative dose of 1 mg/kg dexamethasone reduced the incidence of a composite of death, myocardial infarction, stroke, renal failure, or respiratory failure, within 30 days of randomization. In this substudy, we retrospectively analyzed the occurrence of PPS in 822 patients who were included in the DECS trial and underwent valvular surgery. Postpericardiotomy syndrome was diagnosed if 2 of 5 listed symptoms were present: unexplained fever, pleuritic chest pain, pericardial or pleural rub, new or worsening pericardial or pleural effusion. All medical charts, x-rays, and echocardiograms were reviewed. Secondary end point was the occurrence of complicated PPS, defined as PPS with need for evacuation of pleural effusion, pericardiocentesis, and tamponade requiring intervention or hospital readmission for PPS. This is a blinded, single-center, post hoc analysis.

RESULTS

Postpericardiotomy syndrome occurred in 119 patients (14.5%). The incidence of PPS after dexamethasone compared with placebo was 13.5% vs 15.5% (relative risk 0.88, 95% CI 0.63-1.22). For complicated PPS, the incidence was 3.8% versus 3.2% (relative risk 1.17, 95% CI 0.57-2.41, P = .66), respectively.

CONCLUSION

In patients undergoing valvular cardiac surgery, high-dose dexamethasone treatment had no protective effect on the occurrence of PPS or complicated PPS.

Prevention of infectious complications after heart surgery in children: procalcitonin-guided strategy

Introduction

Infectious complications remain a significant problem of modern cardiac surgery. New prevention strategies, based on the pathogenesis of such complications occurring after cardiopulmonary bypass (CPB) procedures, should be evaluated.

Aim of the study

To evaluate the effectiveness of a procalcitonin (PCT)-guided strategy involving the use of IgM-enriched intravenous immunoglobulins (IVIGs) in children with congenital heart disease with systemic inflammation during the early postoperative period.

Material and methods

Sixty consecutive patients aged 25 (21-30) months who underwent cardiac surgery with CPB and had blood PCT levels > 2 ng/mL on the 1^st postoperative day were enrolled in this single-center prospective randomized clinical trial. The patients were randomized into two groups, comparable in terms of the severity of their initial condition, age, and CPB time. IgM-enriched IVIGs (Pentaglobin, Biotest Pharma GmbH, Germany) were administered during the first 3 postoperative days (5 mL/kg each day) in the study group (n = 30) in addition to the standard treatment, which was also provided to the control group (n = 30). The data are presented as medians with 25-75^th percentiles; they were compared by the Mann-Whitney U-test, and p values of < 0.05 were considered as statistically significant.

Results

Postoperatively, 1/30 (3.3%) patients in the study group and 8/30 (26.7%) in the control group suffered from infectious complications (study group: urinary tract infection [UTI] – 1; control group: pneumonia – 4, pneumonia and sepsis – 2, peritonitis with multiorgan failure – 1, UTI – 1), p = 0.03. The length of hospital stay in the study group was shorter than in the control group: 19 (16-23) days vs. 24 (19-29) days, p = 0.002, as was the length of intensive care unit (ICU) stay: 3 (2-4) days vs. 4 (2-8) days, p = 0.03.

Conclusions

High PCT levels on the 1st postoperative day are associated with an increased risk of infectious complications after cardiac surgery. Early administration of IgM-enriched IVIGs can prevent the development of infectious complications.

Lung inflammatory response syndrome after cardiac-operations and treatment of lornoxicam

The majority of patients survive after extracorporeal circulation without any clinically apparent deleterious effects. However, disturbances exist in various degrees sometimes, which indicate the harmful effects of cardiopulmonary bypass (CPB) in the body. Several factors during extracorporeal circulation either mechanical dependent (exposure of blood to non-biological area) or mechanical independent (surgical wounds, ischemia and reperfusion, alteration in body temperature, release of endotoxins) have been shown to trigger the inflammatory reaction of the body. The complement activation, the release of cytokines, the leukocyte activation and accumulation as well as the production of several "mediators" such as oxygen free radicals, metabolites of arachidonic acid, platelet activating factors (PAF), nitric acid, and endothelin. The investigation continues today on the three metabolites of lornoxicam (the hydroxylated metabolite and two other metabolites of unknown chemical composition) to search for potential new pharmacological properties and activities.

Unchanged plasma levels of the soluble urokinase plasminogen activator receptor in elective coronary artery bypass graft surgery patients and cardiopulmonary bypass use

OBJECTIVE AND DESIGN

The soluble urokinase plasminogen activator receptor (suPAR) has been recently recognized as a potential biological marker of various disease states, but the impact of a major surgical intervention on the suPAR level has not yet been established. The aim of our study was to investigate if the induction of a systemic inflammatory reaction in response to cardiopulmonary bypass would be accompanied by an increase in the plasma suPAR level.

METHODS AND SUBJECTS

Patients undergoing coronary artery bypass grafting under cardiopulmonary bypass (CPB) were added. Based on the baseline suPAR level, patients were divided into group 1 (suPAR within normal range) or group 2 (suPAR above range). Blood was collected before the induction of anesthesia and 6 and 24 hours after surgery. Plasma suPAR, IL-6, IL-8, TNF-α, troponin I, NT-proBNP, and NGAL were quantified to assess the impact of surgical trauma on these markers.

RESULTS

The baseline suPAR level was within the normal range in 31 patients (3.3 ng/mL), and elevated in 29 (5.1 ng/mL) (p<0.001). Baseline mediators of systemic inflammatory reaction concentrations (IL-6, TNF-α, and IL-8) and organ injury indices (troponin I, NT-proBNP, and NGAL) were low and increased after surgery in all patients (p<0.05). The surgery did not cause significant changes in the suPAR level either at 6 or 24 hours after, however the difference between groups observed at baseline remained substantial during the postoperative period.

CONCLUSIONS

There was no change in the suPAR level observed in patients subjected to elective cardiac coronary artery bypass surgery and CPB, despite activation of a systemic inflammatory reaction.

Role of MIF in myocardial ischaemia and infarction: insight from recent clinical and experimental findings

First discovered in 1966 as an inflammatory cytokine, MIF (macrophage migration inhibitory factor) has been extensively studied for its pivotal role in a variety of inflammatory diseases, including rheumatoid arthritis and atherosclerosis. Although initial studies over a decade ago reported increases in circulating MIF levels following acute MI (myocardial infarction), the dynamic changes in MIF and its pathophysiological significance following MI have been unknown until recently. In the present review, we summarize recent experimental and clinical studies examining the diverse functions of MIF across the spectrum of acute MI from brief ischaemia to post-infarct healing. Following an acute ischaemic insult, MIF is rapidly released from jeopardized cardiomyocytes, followed by a persistent MIF production and release from activated immune cells, resulting in a sustained increase in circulating levels of MIF. Recent studies have documented two distinct actions of MIF following acute MI. In the supra-acute phase of ischaemia, MIF mediates cardioprotection via several distinct mechanisms, including metabolic activation, apoptosis suppression and antioxidative stress. In prolonged myocardial ischaemia, however, MIF promotes inflammatory responses with largely detrimental effects on cardiac function and remodelling. The pro-inflammatory properties of MIF are complex and involve MIF derived from cardiac and immune cells contributing sequentially to the innate immune response evoked by MI. Emerging evidence on the role of MIF in myocardial ischaemia and infarction highlights a significant potential for the clinical use of MIF agonists or antagonists and as a unique cardiac biomarker.

Safety and efficacy of intensive intraoperative glycaemic control in cardiopulmonary bypass surgery: a randomised trial

BACKGROUND

This study aimed to determine the safety and efficacy of intraoperative intensive glycaemic treatment with modified glucose-insulin-potassium solution by hyperinsulinemic normoglycaemic clamp in cardiopulmonary bypass surgery patients. We hypothesised that the treatment would reduce infection rates in this group of patients.

METHODS

A prospective, randomised, double-blind trial was conducted in cardiopulmonary bypass surgery patients. A total of 199 adult patients (out of a planned 400) were randomly allocated to intensive or conventional treatment with target glucose levels of 4.4-8.3 mmol/l and < 13.8 mmol/l, respectively. The primary outcomes were clinical infection and cytokine levels, including interleukin (IL)-6 and IL-10. The secondary outcomes were morbidity and mortality.

RESULTS

The study was terminated early because of safety concerns (hypoglycaemia). The clinical post-operative infection rate was 17% in the intensive group and 13% in the conventional group (P = 0.53). The proportion of patients with hypoglycaemia was significantly higher in the intensive group (23%) compared with the conventional group (3%) (P < 0.001). Morbidity and mortality rates were similar for both groups. Anaesthetic duration > 2 h (vs. ≤ 2 h), pre-operative IL-6 level > 15 pg/ml (vs. ≤ 15 pg/ml) and post-operative IL-6 level 56-110 pg/ml (vs. ≤ 55 pg/ml) were independent predictors for post-operative infection.

CONCLUSIONS

Intraoperative intensive glycaemic treatment significantly increased the risk of hypoglycaemia, but its effect on post-operative infection by clinical assessment could not be determined. Anaesthetic duration, pre-operative and post-operative IL-6 levels can independently predict post-operative infection.

Inflammatory Response in Patients under Coronary Artery Bypass Grafting Surgery and Clinical Implications: A Review of the Relevance of Dexmedetomidine Use

Despite the fact that coronary artery bypass grafting surgery (CABG) with cardiopulmonary bypass (CPB) prolongs life and reduces symptoms in patients with severe coronary artery diseases, these benefits are accompanied by increased risks. Morbidity associated with cardiopulmonary bypass can be attributed to the generalized inflammatory response induced by blood-xenosurfaces interactions during extracorporeal circulation and the ischemia/reperfusion implications, including exacerbated inflammatory response resembling the systemic inflammatory response syndrome (SIRS). The use of specific anesthetic agents with anti-inflammatory activity can modulate the deleterious inflammatory response. Consequently, anti-inflammatory anesthetics may accelerate postoperative recovery and better outcomes than classical anesthetics. It is known that the stress response to surgery can be attenuated by sympatholytic effects caused by activation of central (α-)2-adrenergic receptor, leading to reductions in blood pressure and heart rate, and more recently, that they can have anti-inflammatory properties. This paper discusses the clinical significance of the dexmedetomidine use, a selective (α-)2-adrenergic agonist, as a coadjuvant in general anesthesia. Actually, dexmedetomidine use is not in anesthetic routine, but this drug can be considered a particularly promising agent in perioperative multiple organ protection.

Effect of additional preoperative administration of the neutrophil elastase inhibitor sivelestat on perioperative inflammatory response after pediatric heart surgery with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) elicits a systemic inflammatory response. Our previous reports revealed that prophylactic sivelestat administration at CPB initiation suppresses the postoperative acute inflammatory response due to CPB in pediatric cardiac surgery. The purpose of this study was to compare the effects of sivelestat administration before CPB and at CPB initiation in patients undergoing pediatric open-heart surgery. Twenty consecutive patients weighing 5-10 kg and undergoing ventricular septal defect closure with CPB were divided into pre-CPB (n = 10) and control (n = 10) groups. Patients in the pre-CPB group received a 24 h continuous intravenous infusion of 0.2 mg/kg/h sivelestat starting at the induction of anesthesia and an additional 0.1 mg/100 mL during CPB priming. Patients in the control group received a 24-h continuous intravenous infusion of 0.2 mg/kg/h sivelestat starting at the commencement of CPB. Blood samples were tested. Clinical variables including blood loss, water balance, systemic vascular resistance index, and the ratio between partial pressure of oxygen and fraction of inspired oxygen (P/F ratio) were assessed. White blood cell count and neutrophil count as well as C-reactive protein levels were significantly lower in the pre-CPB group according to repeated two-way analysis of variance, whereas platelet count was significantly higher. During CPB, mixed venous oxygen saturation remained significantly higher and lactate levels lower in the pre-CPB group. Postoperative alanine aminotransferase and blood urea nitrogen levels were significantly lower in the pre-CPB group than in the control group. The P/F ratio was significantly higher in the pre-CPB group than in the control group. Fluid load requirement was significantly lower in the pre-CPB group.Administration of sivelestat before CPB initiation is more effective than administration at initiation for the suppression of inflammatory responses due to CPB in pediatric open-heart surgery, with this effect being confirmed by clinical evidence.

Effect of lornoxicam in lung inflammatory response syndrome after operations for cardiac surgery with cardiopulmonary bypass

BACKGROUND

The establishment of Extracorporeal Circulation (EC) significantly contributed to improvement of cardiac surgery, but this is accompanied by harmful side-effects. The most important of them is systemic inflammatory response syndrome. Many efforts have been undertaken to minimize this problem but unfortunately without satisfied solution to date.

MATERIALS AND METHODS

Lornoxicam is a non steroid anti-inflammatory drug which temporally inhibits the cycloxygenase. In this clinical trial we study the effect of lornoxicam in lung inflammatory response after operations for cardiac surgery with cardiopulmonary bypass. In our study we conclude 14 volunteers patients with ischemic coronary disease undergoing coronary artery bypass grafting with EC. In seven of them 16 mg lornoxicam was administered iv before the anesthesia induction and before the connection in heart-lung machine. In control group (7 patients) we administered the same amount of normal saline.

RESULTS

Both groups are equal regarding pro-operative and intra-operative parameters. The inflammatory markers were calculated by Elisa method. We measured the levels of cytokines (IL-6, IL-8, TNF-a), adhesion molecules (ICAM-1, e-Selectin, p-Selectin) and matrix metaloproteinase-3 (MMP-3) just after anesthesia induction, before and after cardiopulmonary bypass, just after the patients administration in ICU and after 8 and 24 hrs. In all patients we estimated the lung's inflammatory reaction with lung biopsy taken at the begging and at the end of the operation. We calculated hemodynamics parameters: Cardiac Index (CI), Systemic Vascular Resistance Index (SVRI), Pulmonary Vascular Resistance Index (PVRI), Left Ventricular Stroke Work Index (LVSWI), Right Ventricular Stroke Work Index (RVSWI), and the Pulmonary arterial pressure, and respiratory parameters too: alveolo-arterial oxygen difference D (A-a), intrapulmonary shunt (Qs/Qt) and pulmonary Compliance. IL-6 levels of lornoxicam group were statistical significant lower at 1st postoperative day compared to them of control group (113±49 and 177±20 respectively, P=0.008). ICAM-1 levels were statistical significant lower at the patient admission in ICU, compared to them of control group (177±29 and 217±22 respectively, P=0.014), and the 1st postoperative day compared to them in control group (281±134 and 489±206 respectively, P=0.045). P-selectin levels were statistical significant lower, compared to them in control group in four measurements (97±23 and 119±7 respectively, P=0.030, 77±19 and 101±20 respectively, P=0.044, 86±4 and 105±13 respectively, P=0.06, 116±13 and 158±17 respectively, P=0.000).

CONCLUSIONS

Hemodynamics and respiratory parameters were improved compared to control group, but these differences was not statistical significant. Eosinofil adhesion and sequestration in intermediate tissue of lung parenchyma were significantly lower compared to control group. Also, alveolar edema was not noted in lornoxicam's group. Lornoxicam reduce the inflammatory response in patients undergone coronary artery bypass grafting with extracorporeal circulation. This calculated from levels reduction of IL-6, ICAM-1 και p-Selectin, and from lung pathologoanatomic examination (absence of alveolar edema, reduce in eosinofil adhesion and sequestration in intermediate tissues). Despite the favorable effect of lornoxicam on the hemodinamics and respiratory parameters these improvement did not seem to be statistical significant.

Recipient-related clinical risk factors for primary graft dysfunction after lung transplantation: a systematic review and meta-analysis

Background

Primary graft dysfunction (PGD) is the main cause of early morbidity and mortality after lung transplantation. Previous studies have yielded conflicting results for PGD risk factors. Herein, we carried out a systematic review and meta-analysis of published literature to identify recipient-related clinical risk factors associated with PGD development.

Method

A systematic search of electronic databases (PubMed, Embase, Web of Science, Cochrane CENTRAL, and Scopus) for studies published from 1970 to 2013 was performed. Cohort, case-control, or cross-sectional studies that examined recipient-related risk factors of PGD were included. The odds ratios (ORs) or mean differences (MDs) were calculated using random-effects models

Result

Thirteen studies involving 10042 recipients met final inclusion criteria. From the pooled analyses, female gender (OR 1.38, 95% CI 1.09 to 1.75), African American (OR 1.82, 95%CI 1.36 to 2.45), idiopathic pulmonary fibrosis (IPF) (OR 1.78, 95% CI 1.49 to 2.13), sarcoidosis (OR 4.25, 95% CI 1.09 to 16.52), primary pulmonary hypertension (PPH) (OR 3.73, 95%CI 2.16 to 6.46), elevated BMI (BMI≥25 kg/m²) (OR 1.83, 95% CI 1.26 to 2.64), and use of cardiopulmonary bypass (CPB) (OR 2.29, 95%CI 1.43 to 3.65) were significantly associated with increased risk of PGD. Age, cystic fibrosis, secondary pulmonary hypertension (SPH), intra-operative inhaled nitric oxide (NO), or lung transplant type (single or bilateral) were not significantly associated with PGD development (all P>0.05). Moreover, a nearly 4 fold increased risk of short-term mortality was observed in patients with PGD (OR 3.95, 95% CI 2.80 to 5.57).

Conclusions

Our analysis identified several recipient related risk factors for development of PGD. The identification of higher-risk recipients and further research into the underlying mechanisms may lead to selective therapies aimed at reducing this reperfusion injury.

Polymorphisms in glutathione S-transferase are risk factors for perioperative acute myocardial infarction after cardiac surgery: a preliminary study

In the present study we explored glutathione S-transferase (GST) polymorphisms in selected patients who experienced accelerated myocardial injury following open heart surgery and compared these to a control group of patients without postoperative complications. 758 Patients were enrolled from which 132 patients were selected to genotype analysis according to exclusion criteria. Patients were divided into the following groups: Group I: control patients (n = 78) without and Group II.: study patients (n = 54) with evidence of perioperative myocardial infarction. Genotyping for GSTP1 A (Ile105Ile/Ala113Ala), B (Ile105Val/Ala113Ala) and C (Ile105Val/Ala113Val) alleles was performed by using real-time-PCR. The heterozygous AC allele was nearly three times elevated (18.5 vs. 7.7 %) in the patients who suffered postoperative myocardial infarction compared to controls. Contrary, we found allele frequency of 14.1 % for homozygous BB allele in the control group whereas no such allele combination was present in the study group. These preliminary results may suggest the protective role for the B and C alleles during myocardial oxidative stress whereas the A allele may represent predisposing risk for cellular injury in patients undergoing cardiac surgery.

Transcatheter versus surgical aortic valve replacement in patients with diabetes and severe aortic stenosis at high risk for surgery: an analysis of the PARTNER Trial (Placement of Aortic Transcatheter Valve)

OBJECTIVES

The goal of this study was to determine whether a less-invasive approach to aortic valve replacement (AVR) improves clinical outcomes in diabetic patients with aortic stenosis (AS).

BACKGROUND

Diabetes is associated with increased morbidity and mortality after surgical AVR for AS.

METHODS

Among treated patients with severe symptomatic AS at high risk for surgery in the PARTNER (Placement of Aortic Transcatheter Valve) trial, we examined outcomes stratified according to diabetes status of patients randomly assigned to receive transcatheter or surgical AVR. The primary outcome was all-cause mortality at 1 year.

RESULTS

Among 657 patients enrolled in PARTNER who underwent treatment, there were 275 patients with diabetes (145 transcatheter, 130 surgical). There was a significant interaction between diabetes and treatment group for 1-year all-cause mortality (p = 0.048). Among diabetic patients, all-cause mortality at 1 year was 18.0% in the transcatheter group and 27.4% in the surgical group (hazard ratio: 0.60 [95% confidence interval: 0.36 to 0.99]; p = 0.04). Results were consistent among patients treated via transfemoral or transapical routes. In contrast, among nondiabetic patients, there was no significant difference in all-cause mortality at 1 year (p = 0.48). Among diabetic patients, the 1-year rates of stroke were similar between treatment groups (3.5% transcatheter vs. 3.5% surgery; p = 0.88), but the rate of renal failure requiring dialysis >30 days was lower in the transcatheter group (0% vs. 6.1%; p = 0.003).

CONCLUSIONS

Among patients with diabetes and severe symptomatic AS at high risk for surgery, this post-hoc stratified analysis of the PARTNER trial suggests there is a survival benefit, no increase in stroke, and less renal failure from treatment with transcatheter AVR compared with surgical AVR. (The PARTNER Trial: Placement of AoRTic TraNscathetER Valve Trial; NCT00530894).

Combined treatment of ulinastatin and tranexamic acid provides beneficial effects by inhibiting inflammatory and fibrinolytic response in patients undergoing heart valve replacement surgery

OBJECTIVE

To investigate the effect of ulinastatin and tranexamic acid administered alone or in combination on inflammatory cytokines and fibrinolytic system in patients undergoing heart valve replacement surgery during cardiopulmonary bypass (CPB).

BACKGROUND

CPB-induced fibrinolytic hyperfunction and systemic inflammatory response syndrome (SIRS) are the leading causes responsible for the occurrence of postsurgical complications such as postsurgical cardiac insufficiency and lung injury, which may lead to an increase in postsurgical bleeding, prolongation of hospital stay, and increased costs.

METHODS

One hundred twenty patients undergoing heart valve replacement surgery during CPB were randomly assigned into 4 groups of 30 patients each: blank control group (Group C), tranexamic acid group (Group T), ulinastatin group (Group U), and tranexamic acid-ulinastatin combination group (Group D). Physiological saline, tranexamic acid, ulinastatin, and a combination of tranexamic acid and ulinastatin were given to each group, respectively. Arterial blood was collected from the radial artery at 4 time points: after induction of anesthesia (T1), unclamping the ascending aorta (T2), and at 1 hour (T3) and 24 hours (T4) after CPB. The levels of plasma tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), neutrophil elastase (NE), and the concentrations of tissue plasminogen activator (t-PA) and α2-antiplasmin (α2-AP) were detected. The changes in the volume of pericardial mediastinal drainage after surgery were observed and recorded.

RESULTS

The plasma TNF-α, IL-6, and NE levels significantly increased in patients from all 4 groups at time points of T2, T3, and T4 in comparison to those before CPB (P < .05), and the plasma TNF-α and IL-6 levels in groups U and D were significantly lower than those in the other 2 groups (P < .05). The plasma t-PA, α2-AP, and D-dimer concentrations significantly increased in patients from all 4 groups at T2 and T3 compared with those before CPB (P < .05), and the plasma t-PA and D-dimer concentrations were significantly lower in groups T and D than those in groups U and C (P < .05) at T2 and T3. The plasma α2-AP concentrations in groups T and D were significantly higher than those in Group C at T3 (P < .05). The volumes of pericardial mediastinal drainage per body surface area were significantly lower in groups T and D than those in Group C 6 hours after the surgery (P < .05).

CONCLUSIONS

Ulinastatin inhibits the release of inflammatory medium and reduces the inflammatory response during CPB. Tranexamic acid can effectively inhibit the fibrinolytic hyperfunction caused by CPB and thus decreases postsurgical bleeding. In addition, it exhibits a minor anti-inflammatory response. As a consequence, a combined treatment of ulinastatin and tranexamic acid reduces postsurgical bleeding and shortens postoperative hospital stay in patients undergoing heart valve replacement surgery.

Effects of albumin and synthetic polypeptide-coated oxygenators on IL-1, IL-2, IL-6, and IL-10 in open heart surgery

BACKGROUND

In this study, we have tried to demonstrate the effects of coating style used in oxygenators on various hematologic and clinical parameters.

MATERIALS AND METHODS

Twenty-seven patients were included in the study, who had undergone operations because of elective coronary artery disease. Albumin-coated oxygenator was used in Group I. In Group II, a synthetic polypeptide-coated oxygenator was used. C1-inhib (complement), C3c, C4, interleukins (IL-1β, IL2, IL-6, IL-10), and tumor necrosis factor alpha (TNF-α) levels were examined at four different time intervals. Hemoglobin, hematocrit, leukocyte and platelet counts, drainage, and transfused blood volumes were analyzed.

RESULTS

Albumin levels were significantly lower in Group I than those in Group II 5 minutes after the removal of the cross-clamp. Twenty-four hours after the surgery, Group I patients also had a significantly higher white blood cell count compared to Group II patients. TNF-α levels in Group I were always expressed in considerably higher amounts than those in Group II. IL-6 levels were significantly higher in Group I, but IL-10 levels were observed to be higher in Group II (p < 0.05).

CONCLUSION

Synthetic polypeptide-coated advanced technology, which employed oxygenators, had an important attenuator effect on acute phase reactants and also on the inflammatory response.

Massive and long-lasting decrease in vitamin C plasma levels as a consequence of extracorporeal circulation

OBJECTIVE

The use of cardiopulmonary bypass (CPB) is suggested to induce oxidative stress, reflected by an imbalance between prooxidant and antioxidant substances. The majority of studies published have either focused on only one aspect (prooxidant or antioxidant side) or covered only a short observation period. Therefore, the aim of this study was to investigate the long-term effects of CPB on the balance of prooxidative markers and antioxidant substances in one single group of patients, being able to estimate the degree of oxidative stress.

METHODS

Blood samples were taken from 29 patients undergoing cardiovascular surgery beginning the day before surgery through postoperative day 6 (discharge). Plasma concentrations of vitamins C (total ascorbic acid) and E and malondialdehyde were measured by high-performance liquid chromatography. Plasma levels of ascorbyl free radical were determined using electron paramagnetic resonance spectroscopy.

RESULTS

The study showed a significant decrease in vitamin C plasma levels during CPB without any recovery of vitamin C up to the time of discharge. Furthermore, CPB induced a significant increase in malondialdehyde plasma concentrations immediately after unclamping, accompanied by a significant increase in the ascorbyl free radical to total ascorbic acid ratio. The latter stayed elevated until the end of observation.

CONCLUSIONS

Our findings indicate that the oxidative stress event after CPB can be divided into two phases: Immediately after reperfusion, a massive oxidative stress occurs, reflected by the increase in malondialdehyde. During convalescence, there must be an ongoing situation of oxidative stress, especially in the water-soluble compartment, leading to the consumption of vitamin C. Because the main antioxidant substance, vitamin C, did not increase again over the entire observation period, supplementation should be given consideration.

Perioperative cardiovascular system failure in South Asians undergoing cardiopulmonary bypass is associated with prolonged inflammation and increased Toll-like receptor signaling in inflammatory monocytes

BACKGROUND

South Asian ethnicity is an independent risk factor for mortality after coronary artery bypass. We tested the hypothesis that this risk results from a greater inflammatory response to cardiopulmonary bypass (CPB).

METHODS

This was a single-site prospective cohort study. We compared the inflammatory response to CPB in 20 Caucasians and 17 South Asians undergoing isolated coronary artery bypass grafting surgery.

RESULTS

Plasma levels of proinflammatory cytokines (interleukin [IL]-6, IL-8, IL-12, interferon gamma, and tumor necrosis factor) and anti-inflammatory mediators (IL-10 and soluble TNF receptor I) were measured. The Toll-like receptor (TLR) signaling pathway was examined in peripheral blood monocytes by flow cytometry, measuring surface expression of TLR2, TLR4, and coreceptor CD14 and activation of downstream messenger molecules (interleukin-1 receptor-associated kinase 4, nuclear factor kappa from B cells (NF-κB), c-Jun amino-terminal kinase, p38 mitogen-activated protein kinase, and Protein Kinase B). South Asians had persistently higher plasma levels of IL-6 and exhibited increased TLR signaling through the p38 mitogen-activated protein kinase and Protein Kinase B pathways in inflammatory monocytes after CPB. This increased inflammatory response was paralleled clinically by a higher sequential organ failure assessment score (5.1 ± 1.4 versus 1.5 ± 1.6, P = 0.027) and prolonged cardiovascular system failure (23.5% versus 0%) 48 h after CPB.

CONCLUSIONS

South Asians develop an exacerbated systemic inflammatory response after CPB, which may contribute to the higher morbidity and mortality associated with coronary artery bypass in this population. These patients may benefit from targeted anti-inflammatory therapies designed to mitigate the adverse consequences resulting from this response.

Monitoring of anesthetic depth during surgical correction of acquired valvular disorders: single center, randomized trial

OBJECTIVE

The authors' primary objective was to test the hypothesis that Cerebral State Index (CSI)-guided control of anesthetic depth might reduce the consumption of anesthetics and shorten the duration of ICU and hospital stays after surgical correction of combined valve disorders.

DESIGN

Single center, randomized trial.

SETTING

City Hospital Number 1 of Arkhangelsk, Russian Federation.

PARTICIPANTS

Fifty adult patients with combined valve disorders requiring surgical correction.

INTERVENTIONS

The patients were randomized into 2 groups. In the CSI group, anesthetic depth was monitored, and the rate of infusion of propofol was titrated to maintain the depth of anesthesia corresponding to a CSI of 40-60. In the control group, the depth of anesthesia was monitored clinically, and the dosage of propofol was administered according to the recommendations of the manufacturer.

MEASUREMENTS AND MAIN RESULTS

All patients received standard perioperative monitoring. Consumption of anesthetics and length of ICU and hospital stays were recorded. Preoperative patient characteristics did not differ significantly between the groups. In the CSI group, average intraoperative doses of midazolam and propofol were reduced by 41% and 19%, respectively (p<0.01). Maintenance of anesthesia guided by CSI shortened the time until fit for ICU discharge by 50% and reduced the lengths of ICU and postoperative hospital stays by 35% and 25%, respectively (p< 0.05).

CONCLUSIONS

Monitoring of anesthetic depth reduces the requirements for midazolam and propofol, resulting in a faster recovery and a shorter postoperative ICU and hospital stay after surgical correction of combined valve disorders.

Propofol shares the binding site with isoflurane and sevoflurane on leukocyte function-associated antigen-1

BACKGROUND

We previously demonstrated that propofol interacted with the leukocyte adhesion molecule leukocyte function-associated antigen-1 (LFA-1) and inhibited the production of interleukin-2 via LFA-1 in a dependent manner. However, the binding site(s) of propofol on LFA-1 remains unknown.

METHODS

First, the inhibition of LFA-1's ligand binding by propofol was confirmed in an enzyme-linked immunosorbent assay (ELISA) ELISA-type assay. The binding site of propofol on LFA-1 was probed with a photolabeling experiment using a photoactivatable propofol analog called azi-propofol-m. The adducted residues of LFA-1 by this compound were determined using liquid chromatography-mass spectrometry. In addition, the binding of propofol to the ligand-binding domain of LFA-1 was examined using 1-aminoanthracene (1-AMA) displacement assay. Furthermore, the binding site(s) of 1-AMA and propofol on LFA-1 was studied using the docking program GLIDE.

RESULTS

We demonstrated that propofol impaired the binding of LFA-1 to its ligand intercellular adhesion molecule-1. The photolabeling experiment demonstrated that the adducted residues were localized in the allosteric cavity of the ligand-binding domain of LFA-1 called "lovastatin site." The shift of fluorescence spectra was observed when 1-AMA was coincubated with the low-affinity conformer of LFA-1 ligand-binding domain (wild-type [WT] αL I domain), not with the high-affinity conformer, suggesting that 1-AMA bound only to WT αL I domain. In the 1-AMA displacement assay, propofol decreased 1-AMA fluorescence signal (at 520 nm), suggesting that propofol competed with 1-AMA and bound to the WT αL I domain. The docking simulation demonstrated that both 1-AMA and propofol bound to the lovastatin site, which agreed with the photolabeling experiment.

CONCLUSIONS

We demonstrated that propofol bound to the lovastatin site in LFA-1. Previously we showed that the volatile anesthetics isoflurane and sevoflurane bound to this site. Taken together, the lovastatin site is an example of the common binding sites for anesthetics currently used clinically.

Does use of cell saver decrease the inflammatory response in cardiac surgery?

BACKGROUND

The role of a cell-saver device in the inflammatory response to cardiac surgery has not been well documented. We hypothesized that the use of a cell saver may reduce proinflammatory cytokine concentrations in patients undergoing cardiac surgery.

METHODS

57 patients presenting for first-time nonemergency cardiac surgery were prospectively randomized to control or cell salvage groups. Blood samples for inflammatory marker assays were collected from the arterial line on induction of anesthesia, at the end of cardiopulmonary bypass, 1 h after surgery, and 24 h after surgery. Plasma proinflammatory cytokines were analyzed using a sandwich solid-phase enzyme-linked immunosorbent assay.

RESULTS

The highest cytokine levels were observed 1 h after surgery. When comparing serum interleukin levels in both patient groups during the different perioperative periods, we found a higher interleukin-8 concentration 24 h after the procedure, and higher concentrations of the p40 subunit of interleukin-12 at 1 h and 24 h postoperatively. The concentrations of interleukin-6 and p40 were greater in blood stored by the cardiotomy suction system than in blood processed by the cell saver (p = 0.01 in both cases). The interleukin-8 concentration was higher in the blood processed by the cell saver (p = 0.03). No significant differences were observed in interleukin-1 and interferon gamma levels in blood from both systems. Clinical outcomes were similar in both groups.

CONCLUSIONS

Our results suggest that cell salvage in low-risk patients undergoing their first elective cardiac procedure does not decrease the inflammatory response after surgery.

COMT-Val158Met-polymorphism is not a risk factor for acute kidney injury after cardiac surgery

BACKGROUND

Cardiac surgery-associated acute kidney injury (CSA-AKI) depicts a major complication after cardiac surgery using cardiopulmonary bypass (CPB).

OBJECTIVE

CSA-AKI has clearly been linked to increased perioperative morbidity and mortality. Dysregulations of vasomotor tone are assumed to be causal for CSA-AKI. While catechol-O-methyltransferase (COMT) is involved in metabolizing catecholamines, a single-nucleotide polymorphism (SNP) in the COMT gene leads to different enzyme activities according to genotype. Pilot studies found associations between those COMT genotypes and CSA-AKI.

METHODS

We prospectively included 1741 patients undergoing elective cardiac surgery using cardiopulmonary bypass (CPB). Patients were genotyped for COMT-Val158Met-(G/A) polymorphism (rs4680).

RESULTS

Demographic characteristics and procedural data revealed no significant differences between genotypes. No association between COMT genotypes and the RIFLE criteria could be detected. A multiple linear regression analysis for postoperative creatinine increase revealed highly significant associations for aortic cross-clamp time (P < 0.001), CPB time (P < 0.001), norepinephrine (P < 0.001), and age (P < 0.001). No associations were found for COMT genotypes or baseline creatinine. With an R (2) = 0.39 and a sample size of 1741, the observed power of the regression analysis was >99%.

CONCLUSIONS

Based on our results, we can rule out an association between the COMT-Val158Met-(G/A) polymorphism and the appearance of CSA-AKI.

The efficacy of parecoxib on systemic inflammatory response associated with cardiopulmonary bypass during cardiac surgery

AIMS

Cardiopulmonary bypass (CPB) during cardiac surgery is well known to be associated with the development of a systemic inflammatory response. The efficacy of parecoxib in attenuating this systemic inflammatory response is still unknown.

METHODS

Patients undergoing elective mitral valve replacement with CPB were assessed, enrolled and randomly allocated to receive parecoxib (80 mg) or placebo. Blood samples were collected in EDTA vials for measuring serum cytokine concentrations, troponin T, creatinekinase myocardial-brain isoenzyme CK-MB concentrations and white cell counts.

RESULTS

Compared with the control group, IL-6 and IL-8-values in the parecoxib group increased to a lesser extent, peaking at 2 h after the end of CPB (IL-6 31.8 pg ml⁻¹ ± 4.7 vs. 77.0 pg ml⁻¹ ± 14.1, 95% CI -47.6, -42.8, P < 0.001; IL-8 53.6 pg ml⁻¹ ± 12.6 vs. 105.7 pg ml⁻¹ ± 10.8, 95% CI -54.8, -49.4, P < 0.001). Peak concentrations of anti-inflammatory cytokine IL-10 occurred immediately after termination of CPB and were higher in the parecoxib group (115.7 pg ml⁻¹ ± 10.5 vs. 88.4 pg ml⁻¹ ± 12.3, 95% CI 24.7, 29.9, P < 0.001). Furthermore, the increase in neutrophil counts caused by CPB during cardiac surgery was inhibited by parecoxib. The increases in serum troponin T and CK-MB concentrations were also significantly attenuated by parecoxib in the early post-operative days. Peak serum concentrations of CK-MB in both groups occurred at 24 h post-CPB (17.4 μg l⁻¹ ± 5.2 vs. 26.9 μg l⁻¹ ± 6.9, 95% CI -10.9, -8.1, P < 0.001). Peak troponin T concentrations occurred at 6 h post-bypass (2 μg l⁻¹ ± 0.62 vs. 3.5 μg l⁻¹ ± 0.78, 95% CI -1.7, -1.3, P < 0.001).

CONCLUSION

Intra-operative parecoxib attenuated the systemic inflammatory response associated with CPB during cardiac surgery and lowered the biochemical markers of myocardial injury.

The effect of cardiopulmonary bypass and hypothermic circulatory arrest on hepatic histology in newborn animals: an experimental study

Still little is known about the effect of cardiac surgery on neonatal hepatic tissue. We examined the effect of cardiopulmonary bypass (CPB) and the effect of deep hypothermic circulatory arrest (DHCA) on neonatal hepatic tissue. Liver biopsies of neonatal piglets were taken after CPB (n = 4), after DHCA (n = 5), and after surgery without CPB (non-CPB; n = 3). Additionally, findings were compared to those of control piglets (n = 9). The liver specimens were fixed, stained with hematoxylin and eosin, and scored regarding inflammatory reaction, hepatocellular edema, and apoptosis. Inflammation score of treated groups was higher than in control; CPB 2.5 ± 0.5, DHCA 1.6 ± 0.4, non-CPB 1.2 ± 0.6, control 0.4 ± 0.3 (P < 0.001 CPB and DHCA vs. control; P < 0.05 non-CPB vs. control). Hepatic cell edema was more evident after DHCA (score 2.0 ± 0.4 vs. 0.2 ± 0.3 in control and 0.6 ± 0.5 after CPB; P < 0.001 and P < 0.05, respectively). The highest apoptotic cell count was in the non-CPB group (22.3 ± 6.3 vs. 11.4 ± 3.6 in control and 8.9 ± 5.4 after CPB; P < 0.05). The present study showed that (i) surgical trauma induces hepatic cell apoptosis; (ii) CPB increases hepatic inflammatory reaction; and (iii) DHCA amplifies hepatic cell edema.

Measurement of systemic oxygen consumption in patients during extracorporeal membrane oxygenation — description of a new method and the first clinical observations

Background:

Extracorporeal membrane oxygenation (ECMO) provides temporary life-saving support for patients with severe cardiac failure, but is associated with significant morbidity and mortality. While ECMO enables oxygen delivery (DO2), little is known about oxygen consumption (VO2), largely due to technical difficulties. We aimed to introduce the adaptation of respiratory mass spectrometry to measure VO2 in patients during ECMO and to use this unique model to determine the pathological dependency of VO2 on DO2 in humans.

Methods and Patients:

Respiratory mass spectrometry remains the ‘state-of-the-art’ method, allowing the highly sensitive and rapid measurement of VO2 in critically ill patients. The principle and design of the respiratory mass spectrometer are described, together with the setting up of this machine with the ECMO oxygenator and the native lungs of the patients. In two patients with severe dilated cardiomyopathy and little cardiac contraction, the decrease in pump flow and, hence, DO2 by 20% was associated with a decrease in VO2 by 5% and 8%, respectively, whereas the increase in pump flow was not associated with any significant change in VO2.

Conclusions:

The direct measurement of VO2 by respiratory mass spectrometry in ECMO patients provides a unique technique for clinical research on the metabolism and VO2-DO2 relationship in this special group of critically ill patients. Our pilot study is the first to demonstrate a pathological dependency of VO2 on DO2 in humans. Further studies are warranted with this technique to examine the changes and the factors affecting systemic oxygen transport in patients during ECMO.

Evolution of Off-Pump Coronary Artery Bypass Grafting over 15 Years: A Single-Institution Experience of 14,030 Cases

BACKGROUND

: Off-pump coronary artery bypass grafting for multivessel disease is an important alternative to conventional myocardial revascularization using cardiopulmonary bypass. The development of exposure and stabilization techniques has made this surgery simple, safe, and routine. Experience with the technique, its evolution, the learning curve, and the pitfalls is presented.

METHODS

: A retrospective analysis was made of 28,216 patients who underwent elective coronary artery bypass grafting over a 15-year period from January 1990 through December 2004. Isolated off-pump coronary artery bypass grafting was performed in 14,030 patients and on-pump coronary artery bypass grafting in 14,186 patients. The overall period was divided into 3 groups of 5 years each: group I (1990-1994), group II (1995-1999), and group III (2000-2004). Initially, off-pump coronary artery bypass grafting was performed selectively in high-risk patients (eg, atheromatous aorta, severe systemic impairment, chronic obstructive pulmonary disease, octogenarian). Recently (2000-2004), multivessel off-pump coronary artery bypass grafting has been performed electively in 96% to 98% of patients undergoing coronary artery bypass grafting. Patients' medical charts were reviewed for age, preoperative risk factors, operative findings, intraoperative conversion rate to cardiopulmonary bypass, postoperative complications, and length of hospital stay.

RESULTS

: In the years 1990-1994 (group I), mostly high-risk cases and cases with left anterior descending coronary artery lesions were included for off-pump coronary artery surgery. In the years 1995-1999 (group II), patients with double and triple vessel disease presenting for coronary artery bypass surgery were accepted for off-pump surgery irrespective of preoperative risk factors. However, in the years 2000-2004 (group III), off-pump coronary artery bypass surgery was the first choice of approach for any patient presenting for coronary artery bypass surgery. The mean number of grafts was lower in off-pump cases than in on-pump cases in group I (2.0 ± 0.4 vs. 3.2 ± 0.80) and group II (2.6 ± 0.6 vs. 3.3 ± 0.4), whereas the mean number of grafts was higher in off-pump cases than in on-pump cases in group III (3.5 ± 0.2 vs. 3.4 ± 0.8). In groups I and II, the conversion to cardiopulmonary bypass was 5.2% and 5.9%, respectively. The conversion to cardiopulmonary bypass decreased to 1.7% in group III, which was statistically significant. Perioperative myocardial infarction was 5.2% in group I, 1.7% in group II, and 1.5% in group III. The difference between groups II and III was not statistically significant. Hospital mortality was higher in group I (5.2%) than in group II (1.2%) or III (1.1%). The difference between groups II and III was not statistically significant. Length of intensive care unit stay was 36 ± 8 hours in group I, 28 ± 7 hours in group II, and 20 ± 8 hours in group III. These differences were statistically significant. Length of postoperative hospital stay was 8 ± 2 days in group I, 7 ± 2 days in group II, and 5 ± 2 days in group III These differences were statistically significant.

CONCLUSIONS

: As surgeons' experience matures, off-pump coronary artery bypass surgery permits total myocardial revascularization in virtually all patients with multivessel coronary artery disease. Despite a significant learning curve, evolution to routine off-pump coronary artery bypass with good patient outcomes can be achieved with careful patient selection during the "learning curve." The method is safe and reproducible, and patients benefit with shorter intensive care unit and hospital stays.