The inflammatory response and extracorporeal circulation

E-Selectin and Asymmetric Dimethylarginine Levels in Adult Cyanotic Congenital Heart Disease: Their Relation to Biochemical Parameters, Vascular Function, and Clinical Status

Background and Aim: Patients with cyanosis secondary to congenital heart disease (CHD) are characterized by erythrocytosis and increased blood viscosity, which contribute to endothelial dysfunction, increased arterial stiffness, and impaired vascular function, which may affect the final clinical presentation. Asymmetric dimethylarginine (ADMA) and e-selectin (e-sel) are valuable biomarkers for endothelial and vascular dysfunction. Their concentration levels in blood serum have the potential to be an accessible tool that reflects the severity of the disease. We aimed to assess e-sel and ADMA levels and their relationship with the clinical status and endothelial and vascular function. Methods: A cross-sectional study, including 36 adult CHD cyanotic patients [(17 males) (42.3 ± 16.3 years)] with an arterial blood oxygen saturation less than 92% and 20 healthy controls [(10 males) (38.2 ± 8.5 years)], was performed. All the patients underwent a clinical examination, blood testing, and cardiopulmonary tests. Their endothelial function was assessed using the intima media thickness and flow-mediated dilatation. Vascular function, using applanation tonometry methods, was determined using the aortic systolic pressure, aortic pulse pressure, augmentation pressure, augmentation index, pulse pressure amplification, and pulse wave velocity. Results: The concentrations of e-sel and ADMA were significantly higher in the patients with CHD. The E-sel levels correlated positively with red blood cells, hemoglobin concentration, hematocrit, and augmentation pressure; they correlated negatively with blood oxygen saturation, the forced expiratory one-second volume, forced vital capacity, and oxygen uptake. The ADMA levels were found to correlate only with age. Conclusions: The E-sel level, unlike ADMA concentration, reflects the severity of erythrocytosis and hypoxia and, thus, the physical status of patients with cyanotic CHD.

Effects of Dexmedetomidine on Perioperative Glycemic Control in Adult Diabetic Patients Undergoing Cardiac Surgery

BACKGROUND AND OBJECTIVE

To study the effects of dexmedetomidine (DEX) on perioperative blood glucose levels in adult diabetes mellitus (DM) patients undergoing cardiac surgery.

METHODS AND MATERIAL

A prospective, observational study was conducted on 100 adult diabetic patients aged between 18 and 75 years undergoing cardiac surgery with cardiopulmonary bypass (CPB). The patients were divided into two groups (group D and group C) of 50 each. Group D patients received DEX infusion, whereas the group C patients received 0.9% normal saline infusion.

RESULTS

The blood glucose levels, heart rate, mean arterial pressure, and serum potassium levels at different time points were comparable between the two groups (P > 0.05). The mean dose of insulin required in the combined population as well as in both controlled and uncontrolled DM patients was significantly less in group D than in group C (combined population - 36.03 ± 22.71 vs 47.82 ± 30.19 IU, P = 0.0297; uncontrolled DM - 37.36 ± 23.9 IU vs 48.16 ± 25.15 IU, P = 0.0301; controlled DM - 34.7 ± 21.5 IU vs 47.63 ± 35.25 IU, P = 0.0291). Duration of mechanical ventilation and VIS were comparable between the two groups. The incidence of arrhythmias (20% vs 46%, P = 0.0059) and delirium (6% vs 20%, P = 0.0384) was significantly less in group D than in group C. None of the patients in either group had stroke, myocardial ischemia, and mortality.

CONCLUSION

The results suggested that DEX infusion during the intraoperative period was very effective for perioperative glycemic control and reduction of insulin requirement in DM patients undergoing cardiac surgery.

Prolonged cardiovascular pharmacological support and fluid management after cardiac surgery

OBJECTIVE

To identify potentially modifiable risk factors related to prolonged cardiovascular pharmacological support after weaning from cardiopulmonary bypass (CPB).

METHODS

This is a secondary analysis of two prospective cohort study in a specialized cardiac surgery institution in adult patients undergoing cardiac surgery with the use of CPB between August 2016 and July 2017. Prolonged cardiovascular pharmacological support was defined by the need for at least one vasopressor or one inotropic agent 24 hours after separation from CPB. Risk factors were identified among baseline characteristics and peri-operative events through multivariable logistic regression.

RESULTS

A total of 247 patients were included and 98 (39.7%) developed prolonged pharmacological support. In multivariable analysis, left ventricular ejection fraction ≤ 30% (OR 9.52, 95% confidence interval (CI) 1.14; 79.25), elevated systolic pulmonary artery pressure (sPAP) > 30 and ≤ 55 mmHg (moderate) (OR 2.52, CI 1.15; 5.52) and sPAP > 55 mmHg (severe) (OR 8.12, CI 2.54; 26.03), as well as cumulative fluid balance in the first 24 hours after surgery (OR 1.76, CI 1.32; 2.33) were independently associated with the development of prolonged pharmacological support.

CONCLUSIONS

Prolonged cardiovascular pharmacological support is frequent after cardiac surgery on CPB. Severe LV systolic dysfunction, preoperative pulmonary hypertension and postoperative fluid overload are risk factors. Further studies are required to explore if those risk factors could be modified or not.

Influence of cardioplegic solution on incidence of delirium after CABG surgery: Use of Calafiore blood cardioplegia versus HTK - Bretschneider - solution in a single-center retrospective analysis from 2017 to 2021

BACKGROUND

Purpose of the present study is an evaluation of postoperative incidence for delirium after coronary artery bypass surgery (CABG). Study addressed whether application of Histidine-Tryptophan-Ketoglutarate (HTK) solution (Bretschneider) or blood cardioplegia (Calafiore) is associated with increased of postoperative delirium cases.

MATERIALS AND METHODS

In a retrospective, single center evaluation a total number of 273 patients were enrolled in the study from January 2017 to October 2021. There were 124 patients assigned to the Calafiore group blood cardioplegic solution (BCC) and 149 patients were included in the Bretschneider group (HTK). The primary endpoint was the postoperative delirium rate in its frequency of occurrence. Definition of the dilirium status was performed using the Confusion Assessment Method in the Intensive Care Unit (CAM-ICU) score during the first three postoperative days. Secondary endpoints were the time intervals of intensive care duration of stay, mechanical ventilation, total extracorporeal circulation, ischemia and reperfusion. Serum levels of the electrolytes Sodium, Potassium, ionized Calcium, and Chloride were monitored.

RESULTS

Although no significant difference in delirium status between the groups were noticed, on third postoperative day, delirium rate dependent on cardioplegia solution used (HTK 12.0%; BCC 3.0%; p = .024) and duration of intensive care stay differed (HTK 4.5 vs. BCC 3.0 days; p = .001). Although Ischemic time (HTK 73.0 vs. BCC 83.0 min; p < .001) and reperfusion time (HTK 35.0 vs. Calafiore 24.0 min; p < .001) were extended in the BCC group less cases of delirium were diagnosed. Serum sodium levels after HTK cardioplegic infusion were decreased (HTK 129.68 vs. BCC 138.96 mmol/l; p < .001). The significant difference persists up to the hundredth extracorporeal circulation circuit min (p = .005).

CONCLUSION

The present data suggest an impact of the cardioplegic solution used upon postoperative delirium rates. Optimization of cardiac arrest protocols is needed. Present data encourage further prospective studies regarding the impact of cardioplegic solutions on electrolyte imbalance for postoperative delirium rates in CABG surgery.

Development and Validation of a Predictive Score for Prolonged Mechanical Ventilation After Cardiac Surgery

OBJECTIVES

The authors aimed to identify risk factors associated with prolonged mechanical ventilation (PMV) after scheduled cardiac surgery under cardiopulmonary bypass (CPB).

DESIGN

A single-center, observational study.

SETTING

Tertiary hospital.

PARTICIPANTS

All adult patients who underwent scheduled cardiac surgery under cardiopulmonary bypass between January 2017 and December 2017.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

Among the 568 patients included, 68 (12.0%) presented a PMV. The median ventilation time was 5.7 hours in the group without PMV and 85.2 hours in the group with PMV. A logistic regression found five variables independently associated with the occurrence of PMV: (1) prior cardiac surgery, (2) preoperative congestive heart failure, (3) preoperative creatinine clearance <30 mL/min/1.73 m², (4) intraoperative implantation of extracorporeal membrane oxygenation, and (5) serum lactate >4 mmol/L on admission. A predictive score to allow the authors to anticipate PMV was developed from the regression coefficient of perioperative factors independently associated with PMV. With a threshold of 2/13, the score had a sensitivity of 80.9%, a specificity of 80.5%, a positive predictive value of 37.2%, and a negative predictive value of 96.7%. The score then was validated in a distinct cohort.

CONCLUSIONS

The study authors have developed a simple score to predict PMV in patients undergoing cardiac surgery with CPB. This score could allow clinicians to identify a high-risk population that might benefit from specific management upon arrival in the intensive care unit.

Assessment of factors affecting short-term pulmonary functions following cardiac surgery: A prospective observational study

BACKGROUND

Pulmonary complications after cardiac surgery are very common and lead to an increased incidence of post-operative morbidity and mortality. Several factors, either modifiable or non-modifiable, may contribute to the associated unfavorable consequences related to pulmonary function. This study was aimed to investigate the degree of alteration and factors influencing pulmonary function (forced expiratory volume in one second (FEV₁) and forced vital capacity), on third, fifth, and seventh post-operative days following cardiac surgery.

METHODS

This study was executed in 71 patients who underwent on-pump cardiac surgery. Pulmonary function was assessed before surgery and on the third, fifth, and seventh post-operative days. Data including surgical details, information about risk factors, and assessment of pulmonary function were obtained.

RESULTS

The FEV₁ and forced vital capacity were significantly impaired on post-operative days 3, 5, and 7 compared to pre-operative values. The reduction in FEV₁ was 41%, 29%, and 16% and in forced vital capacity was 42%, 29%, and 19% consecutively on post-operative days 3, 5, and 7. Multivariate analysis was done to detect the factors influencing post-operative FEV₁ and forced vital capacity.

DISCUSSION

This study observed a significant impairment in FEV₁ and forced vital capacity, which did not completely recover by the seventh post-operative day. Different factors affecting post-operative FEV₁ and forced vital capacity were pre-operative FEV₁, age ≥60, less body surface area, lower pre-operative chest expansion at the axillary level, and having more duration of cardiopulmonary bypass during surgery. Presence of these factors enhances the chance of developing post-operative pulmonary complications.

The spectrum of myocardial homeostasis mechanisms in the settings of cardiac surgery procedures (Review)

Classic cardiac surgery, determined through the function of cardiopulmonary bypass machine and myocardial cardioplegic arrest, represents the most controlled scenario for cardiomyocyte homeostatic disturbances due to systemic inflammatory response and myocardial reperfusion injury. An increasing number of studies have demonstrated that myocardial cell homeostasis in cardiac surgery procedures is a sequence of molecularly interrelated and overlapping mechanisms in the form of apoptosis, autophagy and necrosis, which are activated by a plethora of induced inflammatory mediators and gene-related signaling pathways. In this study, we outline the molecular mechanisms of the cardiomyocyte adaptive homeostatic process and the associated clinical implications, in the settings of classic cardiac surgery procedures.

A comparison between minimized extracorporeal circuits and conventional extracorporeal circuits in patients undergoing aortic valve surgery: is 'minimally invasive extracorporeal circulation' just low prime or closed loop perfusion ?

INTRODUCTION

Even though results have been encouraging, an unequivocal conclusion on the beneficial effect of minimally invasive extracorporeal circulation (MiECC) in patients undergoing aortic valve surgery cannot be derived from previous publications. Long-term outcomes are rarely reported and a significant decrease in operative mortality has not been shown. Most studies have a limited number of patients and are underpowered. They merely report on short-term results of a heterogeneous intraoperative group using different types of ECC system in aortic valve surgery. The aim of the present study was to determine whether MiECC systems are more beneficial than conventional extracorporeal systems (CECC) with regard to mortality, hospital stay and inflammation and with only haemodilution and blood-air interface as differences.

METHODS

We retrospectively analysed data regarding mortality, hospital stay and inflammation in patients undergoing isolated aortic valve surgery. Forty patients were divided into two groups based on the type of extracorporeal system used; conventional (n=20) or MiECC (n=20).

RESULTS

Perioperative blood product requirements were significantly lower in the MiECC group (MiECC: 0.2±0.5 units vs CECC: 0.9±1.2 units, p=0.004). No differences were seen postoperatively regarding mortality (5% vs 5%, p=0.99), total length of hospital stay (10.6±7.2 days (MiECC) vs 12.1±5.9 days (CECC), p=0.39) or inflammation markers (CRP: MiECC: 7.09±13.62 mg/L vs CECC: 3.4±3.2 mg/L, p=0.89).

CONCLUSION

MiECC provides circulatory support that is equally safe and feasible as conventional extracorporeal circuits. No differences in mortality, hospital stay or inflammation markers were observed.

A Meta-Analysis of Miniaturized Versus Conventional Extracorporeal Circulation in Valve Surgery

The effects of miniaturized extracorporeal circulation in patients operated on for heart valve surgery are still inconsistent. We performed a meta-analysis of eight studies involving 1,011 patients to evaluate the comprehensive effects of miniaturized extracorporeal circulation. The results suggested its application significantly reduced the length of stay in the intensive care unit and total hospital stay after heart valve surgery, but no significant effects on reducing postoperative morbidity and mortality were observed. Further studies with long-term follow-up are needed to confirm our results.

The intraoperative effect of pentoxifylline on the inflammatory process and leukocytes in cardiac surgery patients undergoing cardiopulmonary bypass

Background: Inflammation plays a pivotal role in the pathogenesis of organ dysfunction after cardiopulmonary bypass (CPB). The aim of this study was to investigate whether pentoxifylline (PTX) has effects on the inflammatory process and leukocytes in cardiac surgery patients undergoing CPB.

Material and methods: A double-blind, prospective, randomized, placebo-controlled study was undertaken to assess the effect of PTX on leukocyte counts, tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and C-reactive protein (CRP) levels in 60 patients undergoing CPB for elective coronary artery bypass grafting. In 30 patients, 200 mg of PTX was added to 500 mL NaCl and perfused for 180 min after induction of anaesthesia and also 100 mg of PTX was added to the warm cardioplegic solution; another 30 patients received saline solution as placebo.

Results: All measurements were performed before PTX infusion (T0), after induction of anaesthesia (T1), 30 min after weaning from CPB (T2), and 6 hours (T3) and 24 hours postoperatively (T4). PTX did not change the percentage of eosinophils, basophils, neutrophils, monocytes, or lymphocytes, or CRP levels. In the control group, however, total leukocyte count and IL-6 level at T3 and T4 period were significantly higher than the study group. The progressive increment in TNF-α level observed at each period was also significantly prominent in the control group.

Conclusion: CPB-related whole body inflammatory response could be partially inhibited by intraoperative PTX administration. This effect of PTX would be helpful in preventing the well-known complications of CPB-induced systemic inflammation.

Effect of a miniaturized extracorporeal circulation (MECC™System) on liver function

Objective: To evaluate the effect of a miniaturized extracorporeal circulation system (MECC™System) compared to conventional extracorporeal circulation (ECC) regarding liver function in cardiac surgical patients. Methods: Double indicator dilution measurements were achieved by bolus injection of indocyanine green (ICG) for assessment of cardiac index (CI) and plasma disappearance rate of ICG (PDRig). Measurements were simultaneously performed preoperatively after induction of anaesthesia (T1), following admission on the ICU (T2) and 6 h postoperatively (T3). Results: CI and PDRig were markedly increased after cardiac surgery without significant differences between groups. The percentage increase in CI was significantly correlated to the percentage increase in PDRig in both groups. Conclusion: Liver function improved after cardiac surgery in both groups of patients, which may partly be explained by an increase in CI under mild inotrope support. Differences between the extracorporeal circuits with respect to PDRig appear to be minimal in a group of patients without pre-existing liver injury. Perfusion (2007) 22, 245—250.

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.

Cardiopulmonary bypass and oxidative stress

The development of the cardiopulmonary bypass (CPB) revolutionized cardiac surgery and contributed immensely to improved patients outcomes. CPB is associated with the activation of different coagulation, proinflammatory, survival cascades and altered redox state. Haemolysis, ischaemia, and perfusion injury and neutrophils activation during CPB play a pivotal role in oxidative stress and the associated activation of proinflammatory and proapoptotic signalling pathways which can affect the function and recovery of multiple organs such as the myocardium, lungs, and kidneys and influence clinical outcomes. The administration of agents with antioxidant properties during surgery either intravenously or in the cardioplegia solution may reduce ROS burst and oxidative stress during CPB. Alternatively, the use of modified circuits such as minibypass can modify both proinflammatory responses and oxidative stress.

Impact of age on early outcome after coronary bypass graft surgery using minimized versus conventional extracorporeal circulation

Background

Objective of this study was to evaluate the impact of age on comparative early outcomes after coronary artery bypass graft surgery (CABG) with minimized (MECC) and conventional extracorporeal circulation (CECC).

Methods

A retrospective age-, gender- and operation-matched cohort analysis between January 2005 and December 2010 with a total of 2274 patients undergoing CABG with MECC (n = 1137; 50%) or CECC was performed. Patients were stratified into 4 groups according to age: <59 years, 60–69 years, 70–79 years, and 80 years of age or older. Outcomes were compared within each age group. Patients with preoperative dialysis were excluded from analysis. Primary endpoint was 30-day mortality.

Results

Patients treated with CECC had a significantly higher mean logistic EuroSCORE (6.3% vs. 5.0%; p < 0.001), a slightly lower rate of preoperative myocardial infarction (46% vs. 51%; p = 0.01) and a higher rate of impaired renal function (eGFR < 60 mL/min/1.73 m2: 24% vs. 20%; p = 0.01) compared to MECC-patients. Left internal mammary artery was significantly used more often in MECC patients (93% vs. 86%; p < 0.001). Cardiopulmonary bypass and aortic-cross clamping time were significantly lower in the MECC group (p < 0.001). Overall 30-day mortality was significantly higher in patients treated with CECC (4.4% vs. 2.2%; p = 0.002). Within the different age groups mortality rates were not significantly different except for patients aged 60–69 years (4.5% vs. 1.8%; p = 0.03). Postoperative requirement of renal replacement therapy (4% vs. 2.2%; p = 0.01), respiratory insufficiency (9.9% vs. 6.6%; P = 0.004) and incidence of low cardiac output syndrome (3% vs. 1.2%; p = 0.003) were significantly increased in patients with CECC. Multivariate analysis identified age (p = 0.005; 95% CI 1.01 to 1.08; OR 1.05) among other parameters as an independent risk factor, whereas conventional extracorporeal circulation itself did not present as an independent risk factor for 30-day mortality.

Conclusions

In this matched study sample early outcome was significantly better in patients with MECC compared to CECC, irrespective of age. Prior myocardial infarction estimated GFR < 60 mL and waiving the use of LIMA were independent risk factors for 30-day mortality, which were more present in the CECC group.

Hypothermic versus normothermic cardiopulmonary bypass in patients with valvular heart disease

OBJECTIVE

The aim of this study was to test the hypothesis that normothermic cardiopulmonary bypass (CPB) is as effective as hypothermic CPB in terms of cardiac protection (cTnI level) and outcome in patients with valvular heart disease.

DESIGN

Prospective randomized study.

SETTING

A tertiary cardiothoracic referral center.

PARTICIPANTS

140 patients who had valvular heart disease, with/without coronary artery disease, surgically treated under CPB.

INTERVENTIONS

The patients were allocated randomly to undergo either hypothermic (temperature [T], 31 °C-32 °C) or normothermic CPB (T>36 °C).

MEASUREMENTS AND MAIN RESULTS

The primary endpoint was the dynamics of troponin I. The secondary endpoints were ventilation time, the need for inotropic support, intensive care unit (ICU) and hospital stay durations, complications, and mortality. There were no significant intergroup differences in dynamics of troponin I. Ventilation time was significantly lower in the hypothermic group (6 (5-9) and 8 (5-12); p = 0.01).

CONCLUSIONS

Normothermic CPB in patients with valvular heart disease was as effective as hypothermic perfusion in terms of myocardial protection after the surgery assessed by cTnI release. The short ventilation duration in patients who underwent hypothermic CPB needs to be confirmed in a future investigation.

Glucocorticoids in adult cardiac surgery; old drugs revisited

Glucocorticoids can play a pivotal role in modulating different immune responses. The role of glucocorticoids in cardiac surgery is still controversial as many surgeons are concerned about the potential side effects.

In this review, we looked at the role of glucocorticoid administration in modulating postoperative inflammatory responses, atrial fibrillation (AF) and intimal hyperplasia and whether glucocorticoid use is associated with a significant increase in undesirable postoperative complication.

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.

Effect of remote ischaemic preconditioning on ischaemic-reperfusion injury in pulmonary hypertensive infants receiving ventricular septal defect repair

BACKGROUND

Remote ischaemic preconditioning (RIPC) can reduce ischaemic-reperfusion injury in distant organs. The myocardial and pulmonary protective effect of RIPC in infants with pulmonary hypertension remains unclear. We conducted a randomized controlled trial to evaluate the effect of RIPC in infants receiving ventricular septal defect (VSD) repair.

METHODS

We studied 55 infants with pulmonary hypertension undergoing VSD repair (RIPC group, n=27; control group, n=28). RIPC consisted of four 5 min cycles of lower limb ischaemia and reperfusion. Serum troponin I (TnI) concentrations were measured after induction of anaesthesia and at 1, 6, 12, and 24 h after surgery. Other clinical data such as inotropic score, lung compliance, alveolar-arterial oxygen gradient, oxygen index, mechanical ventilation time, and length of intensive care unit stay were also recorded at each interval.

RESULTS

No differences in patient or surgical characteristics were observed between the two groups. There were no significant differences in postoperative TnI levels according to time (P=0.35) or the total amount of TnI release, expressed as the area under the curve over the 24 h after surgery [RIPC vs control: 207.6 (134.0) vs 274.6 (263.7) h ng ml(-1), P=0.24]. All other clinical data were also comparable.

CONCLUSIONS

RIPC does not reduce the postoperative TnI release after VSD repair in infants with pulmonary hypertension. Additionally, it is difficult to find significant clinical benefits of RIPC in this population. The effect of RIPC varies according to clinical situation and patient condition.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT01313832.

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.

Up-regulation of the Apo/Fas (CD95) complex on neutrophils harvested during cardiac surgery: distinct findings in patients operated on with or without the use of cardiopulmonary bypass

Aims: In a group of patients undergoing cardiac surgery performed both with (“on-pump”) and without the use (“offpump”) of cardiopulmonary bypass (CPB), we studied the changes of neutrophil membrane apoptosis-inducing complex Apo/Fas.

Methods: Expression of Apo/Fas (CD95) on leukocytes was evaluated by flow cytometry.

Results: In “on-pump” patients, we found an increase in the expression of CD95 median intensity fluorescence (MFI) on granulocytes from a baseline level median=56, (Q 1=45.5, Q3=64) to a median=88, (Q1=62, Q 3=109.5; p<0.01) at the 3rd postoperative day and median=74, (Q1=63, Q3=84.5; p<0.01) at the 7th postoperative day. In “off-pump” patients, granulocyte CD95 MFI was median=55, (Q1=51, Q3=84) before surgery. The significant increase was found on the 3rd postoperative day only; median=90, (Q 1=66; Q3=98; p<0.05). A similar pattern in the CD95 expression was also found if percentage changes of granulocyte CD95 MFI were followed. Moreover, the significantly increased Apo/Fas expression expressed as a percentage change of CD95 MFI was found in “on-pump” patients compared to “off-pump” patients, both at the 3rd postoperative day (p<0.05) and at the 7th postoperative day (p<0.01).

Conclusions: This is the first direct evidence of increasing densities of the Apo/Fas complex on neutrophils in cardiac surgical patients.

The inflammatory response to miniaturised extracorporeal circulation: a review of the literature

Conventional cardiopulmonary bypass can trigger a systemic inflammatory response syndrome similar to sepsis. Aetiological factors include surgical trauma, reperfusion injury, and, most importantly, contact of the blood with the synthetic surfaces of the heart-lung machine. Recently, a new cardiopulmonary bypass system, mini-extracorporeal circulation (MECC), has been developed and has shown promising early results in terms of reducing this inflammatory response. It has no venous reservoir, a reduced priming volume, and less blood-synthetic interface. This review focuses on the inflammatory and clinical outcomes of using MECC and compares these to conventional cardio-pulmonary bypass (CCPB). MECC has been shown to reduce postoperative cytokines levels and other markers of inflammation. In addition, MECC reduces organ damage, postoperative complications and the need for blood transfusion. MECC is a safe and viable perfusion option and in certain circumstances it is superior to CCPB.

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.

Interleukin-6 may predict survival in extracorporeal membrane oxygenation treatment

The cytokine network and its association with complement activation during cardiac surgery with cardiopulmonary bypass (CPB) is complex. Extracorporeal membrane oxygenation (ECMO) differs from CPB in duration of days to weeks rather than hours. However, few studies have analyzed the levels of inflammatory mediators during ECMO treatment. Plasma samples from 22 patients [nine neonates, one infant, four children and eight adults (14 males and eight female)] who underwent ECMO treatment were collected prior to, during and after treatment, and analyzed for concentrations of inflammatory and anti-inflammatory cytokines and parameters of complement activation. Seven children were treated for cardiac and seven for pulmonary failure and, in the adult group, four were treated for cardiac and four for pulmonary failure. ECMO was performed with veno-arterial (VA) bypass in all children and five adults, and with veno-venous (VV) bypass in three adults. Fourteen patients survived (64%) and eight (36%) patients died during follow-up. A marked (approximately 99%) and rapid (i.e., within two days) decrease in IL-6 was seen in survivors. The non-survivors were characterized by persistently high IL-6 levels throughout the observation period (i.e., until death). C-reactive protein (CRP) levels showed a similar pattern as the IL-6, with higher levels in non-survivors throughout the observation period. However, in contrast to IL-6, the differences between survivors and non-survivors reached statistical significance, but only at the end of the observation period. It is possible that early measurements of IL-6 in ECMO patients could give prognostic information beyond that of CRP.

Sepsis is characterized by the increases in percentages of circulating CD4+CD25+ regulatory T cells and plasma levels of soluble CD25

The function of immune system is to protect hosts from invading microorganisms by destroying infected cells while minimizing damage to tissues. Among immune cells, CD4(+)CD25(+) regulatory T cells (Treg cells) control immune responses by limiting infectious processes. However, it remains unclear whether Treg cells are induced in systemic inflammatory response syndrome (SIRS) or infectious SIRS (i.e. sepsis). SIRS and sepsis are associated with stressful inflammatory conditions. We therefore measured CD25(+) T cells and circulating CD4(+) T cells, along with plasma levels of CD25, interleukin (IL)-6, and IL-10, in 20 septic patients (64 +/- 11 years), 16 SIRS patients (59 +/- 16 years), and control subjects: 13 elderly (60 +/- 16 years) and 14 young volunteers (28 +/- 3 years). Septic patients (23.3 +/- 11.8%, p < 0.01) showed significantly higher percentages of CD25(+) cells among CD4(+) T cells (i.e. Treg cells) than did either young (10.6 +/- 3.7%) or elderly volunteers (11.1 +/- 3.8%). The percentages of Treg cells in septic patients were higher than those in SIRS patients (12.4 +/- 6.9%, p < 0.01). Moreover, plasma levels of soluble CD25 were significantly higher in septic patients, compared to the levels in SIRS patients or volunteers (p < 0.01). No significant difference in plasma levels of IL-6 or IL-10 was found between septic patients and SIRS patients. Thus, sepsis is associated with the increased percentages of Treg cells and elevated plasma level of soluble CD25. The elevation of these parameters might be a useful marker of infections in SIRS.

Integrity of the Cerebral Blood-Flow Response to Hyperoxia After Cardiopulmonary Bypass

OBJECTIVE

In this study, the hypothesis that cardiopulmonary bypass (CPB) alters the cerebral blood flow (CBF) vasoconstrictive response to hyperoxia was tested.

DESIGN

A prospective, observational study was conducted.

SETTING

The study was conducted at a single university hospital.

PARTICIPANTS

Subjects were patients who presented for cardiac surgery with CPB.

INTERVENTIONS

CBF was measured before and after CPB in 12 subjects while breathing 21% O(2) and 100% O(2). CBF was measured by using continuous arterial spin labeling (CASL) perfusion magnetic resonance imaging. Arterial pO(2) (mmHg), pCO(2) (mmHg), hemoglobin (Hgb), and oxygen content (CaO(2)) were also measured.

MEASUREMENTS AND MAIN RESULTS

Mean age of the 12 subjects was 63 +/- 16 years. Hgb decreased from 12.0 (+/-2.4) g/dL to 9.2 (+/-2.9) g/dL postoperatively (p = 0.008). CBF increased by 39%, from 37.2 (+/-10.8) mL/100 g/min to 49.2 (+/-14.3)mL/100 g/min postoperatively (p = 0.01). In response to the hyperoxic challenge CBF decreased by 8.0 (+/-7.1) mL/100 g/min (21%) preoperatively and by 9.4 (+/-6.4) mL/100 g/min (19%) postoperatively (p = 0.58). By using multiple regression, the contribution of CPB to the hyperoxic CBF response (DeltaCBF) was evaluated, while controlling for other potentially important covariates known to influence CBF, including age, baseline CBF on 21% O(2), and changes in arterial pO(2), pCO(2), and CaO(2). CPB state was not found to be a significant covariate in controlling the CBF response to hyperoxia.

CONCLUSIONS

CPB does not impair the CBF response to hyperoxia.

Effects of minimal dose aprotinin on blood loss and fibrinolytic system-complement activation in coronary artery bypass grafting surgery

BACKGROUND

To determine whether 500,000 KIU aprotinin is effective to reduce blood loss in coronary artery bypass grafting (CABG) and to evaluate the effects of this regimen on hematologic parameters.

METHODS

Forty-four patients scheduled for primary CABG were randomly assigned to the aprotinin (n = 24) or control group (n = 20). In aprotinin group, aprotinin was administered in two equal doses (before skin incision and added to the pump prime). Ventilation time, intensive care unit stay, mediastinal tube drainage, hospitalization, transfusion requirements, and postoperative morbidities and mortality were noted. Hematologic markers of fibrinolytic activity and complement activation were also measured pre- and postoperatively.

RESULTS

Although less mediastinal drainage occurred in aprotinin group, the difference was not statistically significant. Other postoperative variables like transfusion requirements, morbidities, and mortality were also found to be similar between groups. Among hematologic parameters, only postoperative levels of alpha2-antiplasmin and plasminogen activator inhibitor-1 were significantly higher in aprotinin group.

CONCLUSIONS

Although plasmin inhibitors begin to rise at this very low aprotinin dosage, it is not advisable to use this aprotinin regimen in CABG patients.

The hemodynamic effects of methylene blue when administered at the onset of cardiopulmonary bypass

Hypotension occurs during cardiopulmonary bypass (CPB), in part because of induction of the inflammatory response, for which nitric oxide and guanylate cyclase play a central role. In this study we examined the hemodynamic effects of methylene blue (MB), an inhibitor of guanylate cyclase, administered during cardiopulmonary bypass (CPB) to patients taking angiotensin-converting enzyme inhibitors. Thirty patients undergoing cardiac surgery were randomized to receive either MB (3 mg/kg) or saline (S) after institution of CPB and cardioplegic arrest. CPB was managed similarly for all study patients. Hemodynamic data were assessed before, during, and after CPB. The use of vasopressors was recorded. All study patients experienced a similar reduction in mean arterial blood pressure (MAP) and systemic vascular resistance (SVR) with the onset of CPB and cardioplegic arrest. MB increased MAP and SVR and this effect lasted for 40 minutes. The saline group demonstrated a persistently reduced MAP and SVR throughout CPB. The saline group received phenylephrine more frequently during CPB, and more norepinephrine after CPB to maintain a desirable MAP. The MB group recorded significantly lower serum lactate levels despite equal or greater MAP and SVR. In conclusion, administration of MB after institution of CPB for patients taking angiotensin-converting enzyme inhibitors increased MAP and SVR and reduced the need for vasopressors. Furthermore, serum lactate levels were lower in MB patients, suggesting more favorable tissue perfusion.

Increased interleukin-6 after cardiac surgery predicts infection

Early diagnosis and treatment of infection after cardiac surgery with cardiopulmonary bypass (CPB) improves outcome. Conventional laboratory tests, such as C-reactive protein and white blood cell count can not distinguish patients with early infection from those with systemic inflammatory response syndrome but without infection. After CPB, there is a systemic release of proinflammatory and antiinflammatory cytokines, including tumor necrosis factor-alpha, interleukin (IL)-6, and IL-10. We investigated the predictive ability of these variables for infection after cardiac surgery. Forty-six patients with impaired left ventricular ejection fraction (<60%), scheduled for cardiac surgery, were included. Plasma samples were drawn 1 day before and immediately before surgery, on admission to the intensive care unit, and on days 1, 3, and 7 after surgery. Infection was identified according to the criteria of the Centers for Disease Control and Prevention. After surgery 13 patients developed an infection. In patients with infection, confirmed a median of 4 days after surgery, all measurements of IL-6, and IL-10 on postoperative day 3 were significantly increased. Tumor necrosis factor-alpha, leukocytes, and C-reactive protein were not increased in these patients. Immediately after surgery blood glucose was significantly increased in patients with infection. Increased IL-6 after CPB is predictive of infection after cardiac surgery in patients with impaired left ventricular function.

Normothermic Beating Heart Surgery with Assistance of Miniaturized Bypass Systems: The Effects on Intraoperative Hemodynamics and Inflammatory Response

The use of miniaturized cardiopulmonary bypass (CPB) circuits and avoidance of cardioplegic arrest are attempts to reduce the inflammatory response to cardiac surgery. We studied the effects of beating heart surgery (BHS) with assistance of simplified bypass systems (SBS) on global hemodynamics, myocardial function and the inflammatory response to CPB. We hypothesized that the use of SBS was associated with less hemodynamic instability after CPB resulting from attenuation of the inflammatory response when compared with surgery performed with a conventional CPB (cCPB) circuit. Forty-five patients undergoing coronary artery bypass grafting were prospectively studied. Fifteen patients were randomized to the use of a cCPB circuit, cold crystalloid cardioplegia, and moderate hypothermia. Two groups of 15 patients underwent BHS during normothermia with assistance of two different SBS consisting of only blood pump and oxygenator. Hemodynamic variables were assessed with transpulmonary thermodilution and transesophageal echocardiography. Plasma levels of proinflammatory and antiinflammatory mediators were measured perioperatively. After CPB, variables of global hemodynamics and systolic ventricular function did not differ among groups. Left ventricular diastolic function was impaired after CPB equally in all groups (P < 0.01 versus pre-CPB). At the end of surgery, there was more need for vasopressor (norepinephrine) support in both SBS groups than in the cCPB group (P < 0.01). After CPB, the release of interleukin (IL)-6 did not differ significantly among groups, whereas plasma levels of IL-10 were higher in the cCPB group (P < 0.01 versus SBS). The extent of myocardial necrosis (Troponin T) was comparable in all groups. We conclude that in our study, miniaturizing bypass systems and avoidance of cardioplegic arrest were not effective in improving hemodynamic performance and in attenuating the proinflammatory immune response after CPB.

The Effect of Cardiopulmonary Bypass on the Expression of Inducible Nitric Oxide Synthase, Endothelial Nitric Oxide Synthase, and Vascular Endothelial Growth Factor in the Internal Mammary Artery

OBJECTIVE

Endothelial function of a vessel may be impaired by local or systemic inflammation initiated by cardiopulmonary bypass (CPB) during coronary artery bypass graft (CABG) surgery. The present study was designed to investigate the early effects of CPB on nitric oxide production and vascular endothelial growth factor (VEGF) expression in internal mammary artery (IMA).

DESIGN

Prospective study.

SETTING

University hospital.

PARTICIPANTS

Twenty patients who were scheduled for elective CABG with CPB.

INTERVENTIONS

IMA sections were studied immunohistochemically from these patients. The samples were taken from the distal end of the IMA before the institution of CPB and just before the construction of the IMA-left anterior descending artery anastomosis.

MEASUREMENT AND MAIN RESULTS

After CPB, VEGF and endothelial nitric oxide synthase immunoreactivity increased significantly when compared with baseline values in the endothelium (p = 0.0156, p = 0.0313) and adventitia (p = 0.0313, p = 0.0001), respectively. No significant change was observed in inducible nitric oxide synthase immunoreactivity.

CONCLUSIONS

The increase in eNOS expression may have been induced by the inflammation caused by CPB.

Increased interleukin-10 and cortisol in long-term alcoholics after cardiopulmonary bypass: a hint to the increased postoperative infection rate?

BACKGROUND

Previous studies have shown that 20% of all patients admitted to the hospital abuse alcohol and have increased morbidity after surgery. Long-term alcoholic patients are shown to suffer from immune alterations, which might be critical for adequate postoperative performance. Cardiac surgery with cardiopulmonary bypass (CPB) also leads to pronounced immune alteration, which might be linked with patients' ability to combat infections. Therefore, the aim of our study was to investigate the perioperative levels of TNF-alpha, interleukin-6, interleukin-10, and cortisol in long-term alcoholic and nonalcoholic patients undergoing cardiac surgery to elucidate a possible association with postoperative infections.

METHODS

Forty-four patients undergoing elective cardiac surgery were included in this prospective study. Long-term alcoholic patients (n=10) were defined as having a daily ethanol consumption of at least 60 g and fulfilling the Diagnostic and Statistical Manual of Mental Disorders for alcohol abuse. The nonalcoholic patients (n=34) were defined as drinking less than 20 g ethanol per day. Blood samples were obtained to analyze the immune status upon admission to hospital, the morning before surgery and on admission to the ICU, the morning of days one and three after surgery.

RESULTS

Basic characteristics of patients did not differ between groups. Long-term alcoholics had a fourfold increase in postsurgery infection rate and prolonged need for ICU treatment and mechanical ventilation. Postoperative levels of interleukin-10 and cortisol were significantly increased in long-term alcoholic patients compared with nonalcoholic patients. These observations were in line with postoperative interleukin-10 being predictive for postoperative infectious complications.

CONCLUSIONS

The increased infection rate in long-term alcoholics strengthens the urgent need for interventional approaches providing modulation of the perioperative immune and HPA response in these high-risk patients to counteract their postoperative immune suppression.

Effects of N-acetylcysteine on pulmonary function in patients undergoing coronary artery bypass surgery with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) has been implicated in causing poor pulmonary gas exchange postoperatively in patients undergoing coronary artery bypass grafting (CABG) procedures. In this prospective, randomized, double-blind, placebo-controlled study, we examined the pulmonary effects of N-acetylcysteine (NAC) in patients undergoing CABG. Twenty patients undergoing elective CABG and early tracheal extubation were randomized into two groups. Group I (ten patients) received a physiologic salt solution as a placebo in a continuous intravenous infusion for one hour before CPB and 24 hours after CPB; Group II (ten patients) received 100 mg/ kg NAC intravenously for one hour before CPB and 40 mg/kg/day at 24 hours after CPB. Perioperative hemodynamic and pulmonary data were recorded. Postoperative tracheal extubation was accomplished at the earliest appropriate time. The postoperative clinical course was similar in the two groups. Both groups exhibited significant postoperative increases in A-a oxygen gradient (p < 0.01), but patients in Group II exhibited significantly lower increases in postoperative A-a oxygen gradient (p < 0.006). Other hemodynamic and pulmonary data (pulmonary capillary wedge pressure, pulmonary vascular resistance (PVR), cardiac index (CI), shunt flow, dynamic lung compliance and static lung compliance) exhibited no differences between the groups. There was no significant difference in terms of intubation time. The malondialdehyde (MDA) increase in Group II following CPB was found to be significantly lower than in Group I (p = 0.043). This clinical study reveals that administration of NAC to patients undergoing elective CABG with CPB improves systemic oxygenation. There was no effect in other pulmonary parameters and in terms of intubation time.

Four years' experience with a miniaturized extracorporeal circulation system and its influence on clinical outcome

It has been suggested that the morbidity associated with cardiopulmonary bypass can be attributed in part to the blood-material and blood-air interactions in the extracorporeal circulation (ECC). A recently introduced minimized ECC-system (MECC System) should be able to reduce these negative effects associated with ECC. A retrospective analysis was performed comprising 485 patients who were operated on for elective coronary artery bypass grafting (CABG) using the MECC System with intermittent antegrade warm blood cardioplegia (group 1) from January 2000 to February 2004. A control group consisted of 485 patients (group 2) undergoing elective CABG in the same period using a conventional ECC and cold crystalloid cardioplegia. There were no significant differences between the two groups in terms of the duration of intubation following surgery, the length of intensive care unit-stay and the total hospital stay. Although the 30-day mortality was similar between the two groups, the incidence of postoperative complications and the perioperative use of blood products were significantly higher in the control group compared to the MECC group. The MECC System may serve as an alternative and less invasive approach to conventional ECC.

Resource utilization in on- and off-pump coronary artery surgery: Factors influencing postoperative length of stay—an experience of 1,746 consecutive patients undergoing fast-track cardiac anesthesia

OBJECTIVE

The purpose of the present investigation was to examine factors influencing resource utilization in patients undergoing on-pump coronary artery bypass graft and off-pump coronary artery bypass (OPCAB) graft surgery at a major university hospital. The resources examined were time to extubation, packed red blood cell (PRBC) transfusion, intensive care length of stay (ICULOS), preoperative and postoperative length of stay (PLOS), and total length of stay (LOS).

DESIGN

Observational study of consecutive patients undergoing on- and off-pump coronary artery bypass surgery.

SETTING

Tertiary care cardiac referral center.

PARTICIPANTS

One thousand seven hundred forty-six consecutive male and female patients undergoing primary coronary artery bypass graft (CABG) surgery over a period of 3 years (1999-2001). Eight hundred eighty-one patients underwent CABG with pump, and 865 patients underwent off-pump coronary artery bypass (OPCAB) surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The mean time to extubation after surgery was 7.4 hours for on-pump patients and 5.8 hours for the OPCAB group (p<or=0.001); 73.7% of patients on pump received PRBC transfusion as compared with 48.6% of the OPCAB group (p<or=0.001). The mean ICULOS for the on-pump group was 1.6 days and 1.4 days for the OPCAB group (p=0.006). PLOS was 6.5 days for the on-pump group and 5.6 days for the OPCAB group (p<or=0.001). Mean total LOS was 9.7 days for the on-pump group and 8.8 days for the OPCAB group (p<or=0.001). PLOS is correlated with several clinical and demographic ariables. Linear and logistic regression models were used to assess the effects of on/off pump on PLOS. Use of pump is significantly correlated with increased PLOS (p<or=0.001, Kendalls correlation), and pump use is strongly associated with transfusion (odds ratio=2.95, p<or=0.001), which in turn is a determinant of PLOS. There were no significant differences between the on- and off-pump groups in the incidence of postoperative complications except for bleeding requiring reexploration and ventilatory support for more than 72 hours. Incidence of bleeding was 3.3% in the on-pump group and 1.7% in the OPCAB group (p=0.038). In the on-pump group, 3% of patients required >72 hours to postoperative tracheal extubation compared with 1.5% in the OPCAB group (p=0.041). Hospital mortality was 2.7% for the on-pump group and 1.0% for the OPCAB group (p=0.010).

CONCLUSION

The authors found that patients undergoing on-pump CABG have significantly longer time to tracheal extubation, increased blood use, longer ICULOS, PLOS, and total LOS and higher in-hospital mortality, which would translate into significant differences in the expenses associated with these 2 surgical approaches to coronary surgery.

Anesthetic myocardial protection with sevoflurane

OBJECTIVE

To examine the role of sevoflurane in myocardial protection in patients undergoing coronary artery bypass graft (CABG) surgery.

DESIGN

Prospective, randomized, controlled, double-blinded study.

SETTING

Veterans Administration Medical Center (VAMC), Buffalo, New York.

SUBJECTS

Twenty-one patients undergoing CABG were included in the study. Eleven patients were randomized to receive sevoflurane, and 10 patients served as controls.

INTERVENTION

Total intravenous anesthesia was provided for both study and control groups by infusion of propofol, fentanyl, and midazolam. Sevoflurane 2% was added to the cardioplegia solution in the experimental group.

MEASUREMENTS AND MAIN RESULTS

Neutrophil beta-integrins (CD11b/CD18), tumor necrosis factor alpha (TNF-alpha), and interleukin (IL)-6 were measured as indicators of the inflammatory response to myocardial ischemia-reperfusion injury. Blood samples were obtained from the aorta and coronary sinus before (T1) and immediately after cardiopulmonary bypass (CPB) (T2) and, in addition, from a peripheral artery 6 hours (T3) after CPB. Myocardial function was determined in all patients at each time point. Left ventricular stroke work index (LVSWI) was calculated as an estimation of left ventricular function. Left ventricular regional wall motion abnormality (RWMA) was assessed by transesophageal echocardiography at T1 and T2 time points. TNF-alpha was detectable only in the control group in arterial samples at T3. IL-6 levels (pg/mL) were found to be lower in the sevoflurane group compared with controls at T2 arterial circulation (38.2 +/- 21.1 v 60.6 +/- 19.1, p < 0.05) as well as in the coronary circulation (38.4 +/- 19.9 v 118.2 +/- 23.5, p < 0.01) at T2. CD11b/CD18 increased 79% after CPB in the control group while only increasing 36% in the sevoflurane group (p < 0.05). The post-CPB LVSWI was back to its baseline values in the sevoflurane group, whereas it was still significantly depressed in the control group. Eight of 10 patients in the control group showed a transient new-onset RWMA in either the septal or anteroseptal regions. Only 2 of 11 patients in the sevoflurane group showed transient RWMA of the LV.

CONCLUSIONS

Sevoflurane decreases the inflammatory response after CPB, as measured by the release of IL-6, CD11b/CD18, and TNF-alpha. Myocardial function after CPB, as assessed by RWMA and LVSWI, was also improved with sevoflurane. The role of sevoflurane in myocardial protection and the inflammatory response to myocardial reperfusion should be considered.

Cardiopulmonary bypass in man: role of the intestine in a self-limiting inflammatory response with demonstrable bacterial translocation

BACKGROUND

Cardiopulmonary bypass provokes a systemic inflammatory reaction that, in 1% to 2% of all cases, leads to multiorgan disfunction. The aim of this study was to evaluate the possible role of the intestine in the pathogenesis and development of this reaction.

METHODS

Eleven selected patients scheduled for elective coronary artery bypass graft surgery were enrolled in a open, prospective clinical study. Gastric tonometry, chromium-labeled test and double sugar intestinal absorption tests, polymerase chain reaction microbial DNA test, and measurement of cytokines and transcriptional factor (nuclear factor kappaB) activation were performed.

RESULTS

During the postoperative period, gastric pH remained stable (range,7.2 to 7.3). The partial pressure for carbon dioxide gradient between the gastric mucosa and arterial blood increased significantly (from 1 to 23 mm Hg), peaking in the sixth postoperative hour. Interleukin 6 increased significantly over basal levels, peaking 3 hours after cardiopulmonary bypass (96.3 versus 24 pg/mL). Nuclear factor kappaB never reached levels higher than those observed after lipopolysaccharide stimulation. Escherichia coli translocation was documented in 10 patients: in eight cases from removal of aortic cross-clamps and in two cases from the first postoperative hour. With respect to basal value (6.4%), the urine collection revealed a significant increase in excretion of the radioisotope during the first 24 hours after surgery (39.1%), although there were no significant variations with the double sugar test.

CONCLUSIONS

The results obtained showed a correlation between the damage of the gastrointestinal mucosa, subsequent increased permeability, E coli bacteremia, and the activation of a self-limited inflammatory response in the absence of significant macrocirculatory changes and postoperative complications.