Extracorporeal Circulation Group Research Articles

A model of hemodialysis after acute kidney injury in rats

BackgroundAcute kidney injury (AKI) is frequent among critically ill patients. Renal replacement therapy (RRT) is often required to deal with severe complications of AKI. This technique is however associated with side effects such as hemodynamic instability and delayed renal recovery. In this study, we aimed to describe a novel model of hemodialysis in rats with AKI and depict a dialysis membrane performance.MethodsEighteen Sprague–Dawley rats received 0.75% adenine-rich diet to induce AKI. After 2 weeks, nine underwent an arterio-venous extracorporeal circulation (ECC) (ECC group) for 2 h without a dialysis membrane on the circuit and nine received a hemodialysis session (HD group) for 2 h with an ECC circuit. All rats were hemodynamically monitored, and glomerular filtration rate (GFR) was measured by transcutaneous fluorescence after the injection of FITC-Sinistrin. Blood samples were collected at different time points to assess serum creatinine and serum urea concentrations and to determine the Kt/V. Sinistrin concentration was also quantified in both plasma and dialysis effluent.ResultsAfter 2 weeks of adenine-rich diet, rats exhibited a decrease in GFR. Both serum urea and serum creatinine concentrations increased in the ECC group but remained stable in the HD group. We found no significant difference in serum creatinine and serum urea concentrations between groups. At the end of experiments, mean serum urea was 36.7 mmol/l (95%CI 19.7–46.9 mmol/l) and 23.6 mmol/l (95%CI 15.2–33.5 mmol/l) in the ECC and HD groups, respectively (p = 0.15), and mean serum creatinine concentration was 158.0 µmol/l (95%CI 108.1–191.9 µmol/l) and 114.0 µmol/l (95%CI 90.2–140.9 µmol/l) in the ECC and HD groups, respectively (p = 0.11). The Kt/V of the model was estimated at 0.23. Sinistrin quantity in the ultrafiltrate raised steadily during the dialysis session. After 2 h, the median quantity was 149.2 µg (95% CI 99.7–250.3 µg).ConclusionsThis hemodialysis model is an acceptable compromise between the requirement of hemodynamic tolerance which implies reducing extracorporeal blood volume (using a small dialyzer) and the demonstration that diffusion of molecules through the membrane is achieved.

Gene Expression of Inflammatory Cytokines in Major Organs by Extracorporeal Circulation.

(1) Background: Extracorporeal circulation (ECC) is indispensable for cardiac surgery. Despite the fact that ECC causes non-physiological damage to blood components, its pathophysiology has not been fully elucidated. In our previous study, we constructed a rat ECC system and observed a systemic inflammatory response during and after blood tests assessing ECC, while the damage per organ localization caused by ECC was not examined. In this study, we used a rat model to assess the gene expression of inflammatory cytokines in major organs during ECC. (2) Methods: The ECC system consisted of a membranous oxygenator, tubing line, and a small roller pump. Rats were divided into a SHAM (which received surgical preparation only, without ECC) group and an ECC group. Proinflammatory cytokines were measured using real-time PCR in major organs after ECC to evaluate local inflammatory responses in the organs. (3) Results: Interleukin (IL)-6 levels were significantly elevated in the ECC group compared to the SHAM group, especially in the heart and lungs. (4) Conclusions: This study suggests that ECC promotes organ damage and the inflammatory response, but the degree of gene expression of proinflammatory cytokines varies from organ to organ, suggesting that it does not uniformly cause organ damage.

The state of cognitive function in patients with stable coronary artery disease after coronary artery bypass grafting.

Aim To study the cognitive function (CF) state in patients with chronic ischemic heart disease (IHD) depending on the method of coronary bypass (CB), with extracorporeal circulation (EC) or on beating heart.Material and methods Postoperative cognitive dysfunction (POCD) is a frequent complication of CB, and its development may depend on the method of surgery, with EC or on beating heart. This single-center, prospective, nonrandomized study included 196 patients with chronic IHD aged 61.0±5.1 years. Patients were divided into two groups based on the CB method: an EC group (n=11) and a beating heart surgery group (n=85). Mean follow-up period was 26±2.1 mos. The state of CF was evaluated before and after CB (at the hospital stage, at 3, 6, 12, and 24 mos.).Results The mean duration of CF recovery was 3 mos. only in the group of CB without EC (p<0.05), whereas after CB with EC, CF parameters were similar to those during the hospital stage with somewhat reduced values. In 6 mos. after CB, CF normalized to baseline values in both groups (with and without EC). A possible CF decline in patients with chronic IHD after CB depended on the following factors: age older than 60 years (p<0.05), diabetes mellitus with glycated hemoglobin >7.5 % (p=0.001) and 6.5-7.5 % (p=0.03), smoking (p=0.04), atherosclerotic damage of the internal carotid artery (p<0.05), and a Charlson comorbidity index >5 (p=0.03). The CB surgery either with EC (p=0.04) or on beating heart (p=0.04) was associated with the development of CD.Conclusion The results of the study allow identifying patients with chronic IHD and POCD-predisposing factors to recommend them beathing heart CB surgery.

Propofol pharmacokinetics and pharmacodynamics-a perspective in minimally invasive extracorporeal circulation.

There is limited evidence as to the pharmacokinetic changes expected in adults with extracorporeal technologies. Drugs may be taken up by various components of the cardiopulmonary bypass circuit itself. Issues include the increased volume of the circuit leading to haemodilution; the sequestration of lipophilic drugs within the circuit tubing; and the absorption of proteins, especially albumin, onto the circuit, which can result in increased free drug. However, in this context, the aspect of pharmacokinetics and pharmacodynamics during minimally invasive extracorporeal circulation has not been described and evidenced by scientific studies. In this single-centre control study of 60 patients undergoing isolated coronary artery bypass grafting, we present the results focused on postoperative albumin values and intraoperative propofol dosages in patients undergoing surgery with minimally invasive (n = 30) versus conventional extracorporeal circulation (n = 30). In the minimally invasive extracorporeal circulation group, a lower propofol dosage titrated to a bispectral index of 40-45 was used during coronary artery bypass grafting, and an improvement of postoperative concentration of serum albumin was observed compared to the conventional extracorporeal circulation group.

Impact of minimally invasive extracorporeal circulation on coagulation-a randomized trial.

Minimally invasive extracorporeal circulation (MiECC) is suggested to have favourable impact on blood loss compared to conventional extracorporeal circulation. We aimed to compare the impact of both systems on coagulation. Randomized trial comparing endogenous thrombin-generating potential early after elective coronary surgery employing either MiECC group (n = 30) or conventional extracorporeal circulation group (n = 30). Secondary outcomes were in vivo thrombin generation, bleeding end points and haemodilution, as well as morbidity and mortality up to 30-day follow-up. Compared to the conventional extracorporeal circulation group, the MiECC group showed (i) a trend towards a higher early postoperative endogenous thrombin-generating potential (P = 0.06), (ii) lower intraoperative levels of thrombin-antithrombin complex and prothrombin fragment 1 + 2 (P < 0.001), (iii) less haemodilution early postoperatively as measured by haematocrit and weight gain, but without correlation to coagulation factors or bleeding end points. Moreover, half as many patients required postoperative blood transfusion in the MiECC group (17% vs 37%, P = 0.14), although postoperative blood loss did not differ between groups (P = 0.84). Thrombin-antithrombin complex levels (rs = 0.36, P = 0.005) and prothrombin fragment 1 + 2 (rs = 0.45, P < 0.001), but not early postoperative endogenous thrombin-generating potential (rs = 0.05, P = 0.72), showed significant correlation to increased transfusion requirements. The MiECC group demonstrated significantly lower levels of creatine kinase-MB, lactate dehydrogenase and free haemoglobin indicating superior myocardial protection, less tissue damage and less haemolysis, respectively. Perioperative morbidity and 30-day mortality did not differ between groups. Conventional but not MiECC is associated with significant intraoperative thrombin generation despite full heparinization. No correlation between coagulation factors or bleeding end points with the degree of haemodilution could be ascertained. NCT03216720.

Impact of minimal invasive extracorporeal circulation on the need of red blood cell transfusion.

Minimal invasive extracorporeal circulation may decrease the need of packed red blood cell transfusions and reduce hemodilution during cardiopulmonary bypass. However, more data are needed on the effects of minimal invasive extracorporeal circulation in more complex cardiac procedures. We compared minimal invasive extracorporeal circulation and conventional extracorporeal circulation methods of cardiopulmonary bypass. A total of 424 patients in the minimal invasive extracorporeal circulation group and 844 patients in the conventional extracorporeal circulation group undergoing coronary artery bypass grafting and more complex cardiac surgery were evaluated. Age, sex, type of surgery, and duration of perfusion were used as matching criteria. Hemoglobin <80 g/L was used as red blood cell transfusion trigger. The primary endpoint was the use of red blood cells during the day of operation and the five postoperative days. Secondary endpoints were hemodilution (hemoglobin drop after the onset of perfusion) and postoperative bleeding from the chest tubes during the first 12 hours after the operation. Red blood cell transfusions were needed less often in the minimal invasive extracorporeal circulation group compared to the conventional extracorporeal circulation group (26.4% vs. 33.4%, p = 0.011, odds ratio 0.72, 95% confidence interval 0.55-0.93), especially in coronary artery bypass grafting subgroup (21.3% vs. 35.1%, p < 0.001, odds ratio 0.50, 95% confidence interval 0.35-0.73). Hemoglobin drop after onset of perfusion was also lower in the minimal invasive extracorporeal circulation group than in the conventional extracorporeal circulation group (24.2 ± 8.5% vs. 32.6 ± 12.6%, p < 0.001). Postoperative bleeding from the chest tube did not differ between the groups (p = 0.808). Minimal invasive extracorporeal circulation reduced the need of red blood cell transfusions and hemoglobin drop when compared to the conventional extracorporeal circulation group. This may have implications when choosing the perfusion method in cardiac surgery.

Minimally invasive versus conventional extracorporeal circulation circuits in patients undergoing coronary artery bypass surgery: a propensity-matched analysis.

Minimally invasive extracorporeal circulation circuits provide several advantages compared to conventional extracorporeal circulation circuits. We compared the results of a minimally invasive extracorporeal circulation system with those of conventional extracorporeal circulation system, in patients undergoing isolated coronary artery bypass grafting. We identified 753 consecutive patients who underwent coronary artery bypass grafting at our centre between October 2014 and September 2016. These patients were divided into two groups: a minimally invasive extracorporeal circulation group (M, n = 229) and a conventional extracorporeal circulation group (C, n = 524). Baseline parameters, details of cardiac surgery as well as postoperative complications and outcomes were compared by means of a propensity-matched analysis of 180 matched pairs. The median EuroSCORE II was 1.3%. Transfusion requirement of packed red blood cells (p = 0.002) was lower in Group M compared to conventional extracorporeal circulation systems. There were no differences in hospital mortality or in rates of adverse events between the matched groups. Total in-hospital mortality of the cohort was 1.7%. The use of minimally invasive extracorporeal circulation is associated with a significantly lower use of blood products after isolated coronary revascularisation. There were no differences concerning duration of surgery, complication rates and mortality between the groups. Therefore, the application of minimally invasive extracorporeal circulation systems should be considered as preferred technique in isolated coronary artery bypass grafting procedures.

Minimally Invasive Extracorporeal Bypass in Minimally Invasive Heart Valve Operations: A Prospective Randomized Trial

Minimally invasive extracorporeal circulation (MECC) is predominantly used in coronary operations. Data supporting the benefits of MECC in minimally invasive valve operations are still absent. Patients undergoing either isolated minimally invasive mitral or aortic valve procedures were prospectively randomized to a minimally invasive group (MECC; n= 101) or a conventional extracorporeal circulation group (CECC; n= 99). The procedural and postoperative outcomes were compared, including the levels of inflammation factors (procalcitonin, interleukin [IL]-6, IL-8, and IL-10), tumor necrosis factor-α [TNF-α], and interferon-gamma [IFN-γ]). The demographics were comparable between the groups regarding age (MECC versus CECC, 70.5 ± 10.2 years versus 73.1 ± 8.9 years; P= 0.086), left ventricular function (59.2% ± 13.4% versus 62.1% ± 14.0%; p= 0.302), EuroSCORE (7.4% ± 7.9% versus 6.8% ± 4.0%; p= 0.256), and other comorbidities. Hospital mortality (n= 1 versus n= 3; p= 0.339) and other complications were similar. However, hemoglobin level (111.9 ± 19.0 g/L versus 103.8 ± 14.6 g/L; p= 0.001), the number of packed red blood cells (PRBCs) (1.1 ± 1.9 versus 1.7 ± 1.8; p= 0.003), the levels of ILs (IL-6, 194.0 ± 131.8 pg/mL versus 289.2 ± 62.5 pg/mL; p= 0.020; IL-8, 38.1 ± 27.3 pg/mL versus 45.8 ± 43.4 pg/mL; p= 0.012; IL-10, 29.0 ± 123.9 pg/mL versus 49.9 ± 85.6 pg/mL; p= 0.012), TNF-α (3.8 ± 6.7 ng/mL versus 10.8 ± 47.7 ng/mL; p= 0.049), and IFN-γ (1.9 ± 1.9 pg/mL versus 4.5 ± 2.7 pg/mL; p= 0.027) were in favor of patients in the MECC group. Additionally, those patients had shorter postoperative ventilation time (7.7 ± 8.4 hours versus 9.3 ± 12.9 hours; p= 0.010) and intensive care unit (ICU) stay (1.2 ± 1.2 days versus 2.2 ± 3.8 days; p= 0.047). The intraprocedural data were excellent and comparable in the groups, but postoperative outcomes were better in the MECC group. Thus MECC is preferable to CECC even for minimally invasive valve procedures. These findings strongly support a combined strategy of minimally invasive valve operations and minimally invasive extracorporeal circulation.

Abstract 14571: Prospective Randomized Comparisonof Miniaturized Extracorporeal Circulation System (MECC) versus Conventional Extracorporeal Circulation System (cecc) in the Prevention of Postoperative Atrial Fibrillation (FA) and Other Clinical Results in Cardiac Surgery Patients

Introduction: Postoperative atrial fibrillation (AF) is the most common arrhythmia to occur after cardic surgery with an incidence between 20-45 %. It is associated with increased morbidity, including increased risk of stroke and need for additional treatment and costs. The pathophysiology of postoperative AF is not fully understood.cardiac surgery with extracorporeal circulation is known to be associated with a systemic inflammatory response,which may be in part responsible for postoperative AF. furthermore,foreign surface contact,blood-air contact,abnormal blood flow and hemodilution are broblems related to extracorporeal circulation. Hypothesis and Methods: In this prospective,randomized,open labelled clinical study,240 cardiac surgery patients were randomized either miniaturized extracorporeal circulation (MECC) group or conventional extracorporeal circulation (CECC) group before the surgery. The main outcome measure was the incidence of postoperative atrial fibrillation (AF) during the hospital stay after surgery. Other end points were use of blood products and vasoactive agents and the first (CKMBm) value postoperatively. Results: The incidence of postoperative atrial fibrillation was 43/120 (35.8 %) in the conventional extracorporeal circulation group (CECC) compared with 42/120 (35.0%) in the miniaturized extracorporeal circulation group (MECC) (p=0.893). The use of perioperative vasoactive agents was significantly lower in the (MECC) group compared with (CECC) group . Furthermore, the first postoperative CKMBm value was significantly lower in (MECC) patient group than in (CECC) patient group. There were no difference in the use of blood products between the groups. Conclusion: The clinical use of MECC with cardiac operative patients is safe and results are optimal when this procedure is performed by experienced teams. There were no difference in the incidence of postoperatrive atrial fibrillation (AF) between the groups, but the use of vasoactive agents was lower in (MECC) patient group, than in (CECC) patient group and also the first postoperative (CKMBm) value was lower in the (MECC) group than in (CECC) group.

A novel small animal extracorporeal circulation model for studying pathophysiology of cardiopulmonary bypass.

Extracorporeal circulation (ECC) is indispensable for cardiac surgery. Despite the fact that ECCcauses damage to blood components and is non-physiologic, its pathophysiology has not been fully elucidated. This is because difficulty in clinical research and animal experiments keeps the knowledge insufficient. Therefore, it is desirable to have a miniature ECC model for small animals, which enables repetitive experiments, to study the mechanism of pathophysiological changes during ECC. We developed a miniature ECC system and applied it to the rat. We measured changes in hemodynamics, blood gases and hemoglobin (Hb) concentration, serum cytokines (TNF-α, IL-6, IL-10), biochemical markers (LDH, AST, ALT), and the wet-to-dry weight (W/D) ratio of the lung for assessing whether the rat ECC model is comparable to the human ECC. The ECC system consisted of a membranous oxygenator (polypropylene, 0.03 m(2)), tubing line (polyvinyl chloride), and roller pump. Priming volume of this system is only 8 ml. Rats (400-450 g) were divided into the SHAM group (n = 7) and the ECC group (n = 7). Blood samples were collected before, 60 and 120 min after initiation of ECC. During ECC, blood pressure and Hb were maintained around 80 mmHg and 10 g/dL, respectively. The levels of the inflammatory and biochemical markers and the W/D ratio were significantly elevated in the ECC group, indicating some organ damages and systemic inflammatory responses during ECC. We successfully established the ECC for the rat. This miniature ECC model could be a useful approach for studying the mechanism of pathophysiology during ECC and basic assessment of the ECC devices.

Multiple electrode aggregometry for the assessment of acquired platelet dysfunctions during extracorporeal circulation.

There have been many reports on how the usage of extracorporeal circulation (ECC) is independently associated with the induction of platelet dysfunctions. The aim of the present investigation was to study the capability of the multiple electrode aggregometry (MEA) using the Multiplate (Roche AG, Grenzach, Germany) device to reflect the extent of ECC-associated platelet dysfunctions. The study population consisted of patients who were treated with either hypothermic (cardiopulmonary bypass [CPB]) or normothermic (extracorporeal membrane oxygenation) ECC. Hemostatic analyses included conventional laboratory coagulation tests and aggregometric measures following stimulation with different agonists using MEA. The area under the aggregation curve in the ADPtest (ex vivo adenosine diphosphate induced platelet aggregation) of the MEA was defined as the primary end point. The analyses were performed before the usage of ECC (baseline) and 90 minutes (T1), 120 minutes (T2), 150 minutes (T3), and 180 minutes (T4) after the usage of ECC. In the hypothermic ECC group, additional hemostatic analyses were performed after the patient's postoperative admission to the intensive care unit (T5). Periprocedural data and results of other hemostatic testing were defined as secondary end points. A total of n = 40 patients were assessed for eligibility and n = 25 patients were finally enrolled into the study (hypothermic ECC group: n = 20; normothermic ECC group: n = 5). The extent of ADP-induced platelet aggregation decreased significantly between baseline and consecutive measuring points during hypothermic ECC and remained unchanged between T4 and T5. In the normothermic ECC group, ADP-induced aggregability was significantly lower at T1 compared with baseline and remained unchanged from T1 onward. Data from the present study indicate that ex vivo ADP-induced platelet aggregation in MEA reflects the time-dependent extent of ECC-induced platelet dysfunction.

Investigation of the biological effects of artificial perfusion using rat extracorporeal circulation model.

Extracorporeal circulation (ECC) is indispensable for cardiac surgery. Since difficulty in clinical research keeps the knowledge insufficient, it is desirable to have a miniature ECC system for small animals. We aimed to establish a miniature ECC system and apply the system to the rat for investigating biochemical changes. The ECC system consisted of a membranous oxygenator (polypropylene, 0.03 m(2)), tubing line (polyvinyl chloride) and roller pump. Priming volume of this system is only 15 ml. Rats were divided into the SHAM group and the ECC group. ECC pump flow was initiated and maintained at 70 ml/kg/min. We measured the serum cytokine levels of tumor necrosis factor-a, interleukin (IL)-6, and IL-10, and biochemical markers (lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase) before, 60, and 120 min after the initiation of ECC. In addition, we measured the wet-to-dry weight (W/D) ratio of the left lung tissues. During ECC, blood pressure and Hb were maintained around 80 mmHg and 10g/dl, the serum cytokine levels and biochemical markers were significantly elevated in the ECC group compared with the SHAM group. The W/D ratio increased significantly more in the ECC group compared with that in the SHAM group. These data suggest that ECC promotes organ damages and systemic inflammatory response. This rat ECC model is considered to be equivalent to the already established human ECC and useful for studying the mechanism of pathophysiological changes during artificial perfusion.

Evaluation of Systemic Inflammatory Response in Cardiovascular Surgery via Interleukin-6, Interleukin-8, and Neopterin

The aim of this study was to evaluate the serum levels of interleukin-6 (IL-6), IL-8, and neopterin as a sign of systemic inflammatory response syndrome after open-heart surgery. In this study, we evaluated the influences on the levels of IL-6, IL-8, and neopterin of coronary artery bypass grafting (CABG) and valve replacement surgeries with and without the use of extracorporeal circulation (ECC). This prospective study was performed in 30 patients. In this study, we evaluated patients who underwent valve replacement surgery (group 1, n = 10), CABG with ECC (group 2, n = 10), or CABG using the beating-heart technique (group 3, n = 10). With the Human Investigation Ethics Committee consent, blood samples were obtained from the patients before the surgery (T0) and after 1 hour (T1), 4 hours (T2), 24 hours (T3), and 48 hours (T4) of protamine injection. IL-6, IL-8, and neopterin levels were measured using commercial enzyme-linked immunosorbent assay kits. The demographic data and preoperative and operative characteristics of the patients were similar. Neopterin IL-6 and IL-8 levels significantly increased first at the fourth hour after the surgery. When compared to the levels before the surgery, this increase was statistically significant. Unlike the other 2 groups of patients, those who experienced CABG with the beating-heart technique (group 3) had decreased neopterin levels at the first hour after the surgery, but this decrease was not statistically significant. Neopterin levels increased later in the OPCAB group, but these increased levels were not as high as the neopterin levels of groups 1 and 2. Neopterin reached maximum levels at the 24th hour and, unlike groups 1 and 2, in group started to decrease at the 48th. Complement activation, cytokine production, and related cellular responses are important factors during open-heart surgery. It is certain that ECC activates the complement systems, and activated complement proteins cause the production of several cytokines. In our study, neopterin levels in patients who underwent beating-heart method surgery were lower than those in the other groups, and these levels started to decrease at the 48th hour. These data suggest that the systemic inflammatory response was less activated in that patient group. The beating-heart method might be an important alternative in CABG surgery to minimize the complications and mortality related to surgery.

Normothermal or Hypothermal Extracorporeal Circulation Regimens in Patients with Acquired Heart Disease

Background. Hypothermal extracorporeal circulation has been used in cardiosurgery over 50 years. However, recent trials have not shown its predominant effect on the protection of the brain, lung, and myocardium in patients during surgery. We have presumed that when normothermal extracorporeal circulation used in patients with acquired heart disease, its pathophysiological effect on the body is comparable with that of hypothermal extracorporeal circulation. Subjects and methods. One hundred and forty patients who were to undergo acquired heart disease correction were randomized into two equal groups: that using hypothermal or normothermal extracorporeal circulation. Perioperative troponin I and NT-proBNP concentrations, postoperative clinical course, and hospital morbidity and mortality rates were estimated. Results. There were no significant differences in the concentrations of troponin I and NT-proBNP at the study stages. In the normothermal extracorporeal circulation group patients with isolated aortic stenosis, the concentration of troponin I was higher than that in the hypothermal extracorporeal circulation group. Analyzing the postoperative course indicated that the duration of mechanical ventilation was significantly lower in the hypothermal extracorporeal circulation group than in the normothermal extracorporeal circulation group. There were no differences in hospital complications and mortality rates. Conclusion. Hypothermal versus normothermal extracorporeal circulation in the correction of acquired heart diseases has no predominant effect on tro-ponin I and NT-proBNP concentrations, postoperative clinical course, and hospital complications and mortality rates. Key words: extracorporeal circulation, hypothermia, acquired heart disease, troponin I, NT-proBNP.

Minimally Invasive Versus Conventional Extracorporeal Circulation in Minimally Invasive Cardiac Valve Surgery

Minimally invasive extracorporeal circulation (MECC) technology was applied predominantly in coronary surgery. Data regarding the application of MECC in minimally invasive valve surgery are missing largely. Patients undergoing isolated minimally invasive mitral or aortic valve procedures were allocated either to conventional extracorporeal circulation (CECC) group (n = 63) or MECC group (n = 105), and their prospectively generated data were analyzed. Demographic data were comparable between the groups regarding age (CECC vs. MECC: 71.0 ± 7.5 vs. 66.2 ± 10.1 years, p = 0.091) and logistic EuroSCORE I (6.2 ± 2.5 vs. 5.4 ± 3.0, p = 0.707). Hospital mortality was one patient in each group (1.6 vs. 1.0%, p = 0.688). The levels of leukocytes were lower in the MECC group (11.6 ± 3.2 vs. 9.4 ± 4.3 109/L, p = 0.040). Levels of platelets (137.2 ± 45.5 vs. 152.4 ± 50.3 109/L, p = 0.015) and hemoglobin (103.3 ± 11.3 vs. 107.3 ± 14.7 g/L, p = 0.017) were higher in the MECC group. Renal function was better preserved (creatinine: 1.1 ± 0.4 vs. 0.9 ± 0.2 mg/dL, p = 0.019). We were able to validate shorter time of postoperative ventilation (9.5 ± 15.1 vs. 6.3 ± 3.4 h, p = 0.054) as well as significantly shorter intensive care unit (ICU) stay (1.8 ± 1.3 vs. 1.2 ± 1.0 d, p = 0.005) for MECC patients. The course of C-reactive protein did not differ between the groups. We were able to prove the feasibility of MECC even in minimally invasive performed mitral and aortic valve procedures. In addition, the use of MECC provides decreased platelet consumption and less hemodilution. The use of MECC in these selected patients lead to a shorter ventilation time and ICU stay.

Study of the Dynamics of Transcephalic Cerebral Impedance Data during Cardio-Vascular Surgery

Postoperative neurological deficits are one of the risks associated with cardio vascular surgery, necessitating development of new techniques for cerebral monitoring. In this study an experimental observation regarding the dynamics of transcephalic Electrical Bioimpedance (EBI) in patients undergoing cardiac surgery with and without extracorporeal circulation (ECC) was conducted to investigate the potential use of electrical Bioimpedance for cerebral monitoring in cardio vascular surgery. Tetrapolar transcephalic EBI measurements at single frequency of 50 kHz were recorded prior to and during cardio vascular surgery. The obtained results show that the transcephalic impedance decreases in both groups of patients as operation starts, however slight differences in these two groups were also observed with the cerebral impedance reduction in patients having no ECC being less common and not as pronounced as in the ECC group. Changes in the cerebral impedance were in agreement with changes of haematocrit and temperature. The origin of EBI changes is still unexplained however these results encourage us to continue investigating the application of electrical bioimpedance cerebral monitoring clinically.

Extracorporeal Circulation Interference on Emergence from Anesthesia in Patients Submitted to Myocardial Revascularization

Extracorporeal circulation (ECC) may change drug pharmacokinetics as well as brain function. The objectives of this study are to compare emergence time and postoperative sedation intensity assessed by the bispectral index (BIS) and the Ramsay sedation scale in patients undergoing myocardial revascularization (MR) with or without ECC. Ten patients undergoing MR with ECC (ECC group) and 10 with no ECC (no-ECC group) were administered with sufentanyl, propofol 2.0 μg.mL(-1) and pancuronium target controlled infusion. After surgery, propofol infusion was reduced to 1 μg.mL(-1) and suspended when extubation was indicated. Patients BIS, Ramsay scale and time to wake up were assessed. The ECC group showed lower BIS values beginning at 60 minutes after surgery (no-ECC = 66±13 and ECC = 53±14, p=0.01) until 120 minutes after infusion (no-ECC = 85±8 and ECC = 73±12, p=0.02). Sedation level measured by the Ramsay scale was higher in the ECC group at 30 minutes after the end of the surgery (no-ECC = 5±1 and ECC = 6±0, p=0.021), at the end of infusion (no-ECC = 5±1 and ECC = 6±1, p=0.012) and 5 minutes after the end of infusion (no-ECC = 4±1 and ECC = 5±0.42, p=0.039). Emergence from anesthesia time was higher in the ECC group (no-ECC = 217±81 and ECC = 319±118, p=0.038). There was a higher intensity of sedation after the end of surgery and a longer wake up time in ECC group, suggesting changes in the pharmacokinetics of propofol or effects of ECC on central nervous system.

Minimized Extracorporeal Circulation in Coronary Artery Bypass Surgery Is Equivalent to Standard Extracorporeal Circulation in Patients with Reduced Left Ventricular Function

Minimized extracorporeal circulation (MECC) is a promising alternative to standard extracorporeal circulation (ECC) and its use is increasing in routine coronary bypass surgery. We analyzed the clinical outcome of patients with reduced left ventricular function who underwent coronary artery bypass surgery with MECC or with standard ECC. From January 2003 to September 2008, 238 patients with a left ventricular function < 30 % underwent bypass surgery with ECC or MECC. The primary end point of our retrospective observational study was 30-day mortality. Secondary endpoints were the transfusion requirements, as well as intensive care and the in-hospital course. Demographic data, comorbidities and left ventricular function were similar in the study groups. MECC patients had a tendency towards a lower 30-day mortality rate, a better postoperative renal function and reduced ventilation times. Extracorporeal circulation time and postoperative high-dose inotropic support were significantly lower in the MECC group, while the stays in the intensive care unit and in hospital were comparable between the two groups. In our study, age in the ECC group, and previous infarction and New York Heart Association grade IV in the MECC group were preoperative risk factors associated with a higher mortality. Coronary bypass surgery using MECC is feasible and safe for patients with severely impaired left ventricular function. It is a promising alternative to ECC with a low mortality rate and a more favorable postoperative course.

Reoperation of the proximal aorta: impact of presternotomy extracorporeal circulation on clinical outcomes

Adverse events can occur during a sternotomy for reoperation of the proximal aorta. Presternotomy extracorporeal circulation is often employed to avoid catastrophic events. The purpose of this study was to investigate the impact of presternotomy extracorporeal circulation on clinical outcomes of redo proximal aortic surgery. Between January 1990 and December 2005 a total of 21 aneurysms or dissections of the proximal aorta were repaired via a repeat sternotomy. Extracorporeal circulation was established before the sternotomy in 9 (49%) patients and after the sternotomy in 12 (51%) patients. There were no statistically significant differences in the age, sex, emergency surgery, chronic obstructive pulmonary disease, and renal function between the groups. Femoral cannulation was used more often in the presternotomy extracorporeal circulation group (8/9, 89% vs. 1/12, 8.3%; P = 0.000). The difference in the pump time did not reach a statistically significant level. The 30-day and in-hospital mortality rates were 11% (1/9) and 11% (1/9) in the presternotomy extracorporeal circulation group and 0% (0/12) and 17% (2/12) in the poststernotomy extracorporeal circulation group. There were no statistically significant differences in stroke, respiratory failure, myocardial infarction, or renal failure. There was a trend toward a longer hospital stay in the presternotomy extracorporeal circulation group (85.8 vs. 48.1 days; P = 0.06). Presternotomy extracorporeal circulation was not associated with any major adverse outcomes such as death, stroke, or renal failure.

Minimised versus conventional cardiopulmonary bypass: outcome of high-risk patients

Coronary artery bypass grafting (CABG) with extracorporeal circulation (ECC) is the gold standard for surgical coronary re-vascularisation. Recently, minimised extracorporeal circulation system (MECC) has been postulated a safe and advantageous alternative for multi-vessel CABG. Between January 2004 and December 2007, 244 high-risk patients (logistic EuroScore (ES)>10%) underwent CABG in our institution. ECC was used in 139 (57%) and MECC in 105 (43%) patients. Demographic data including age (MECC: 73.4+/-7.4 years; ECC: 73.3+/-6.4 years), ES (MECC: 19.2+/-9.8%; ECC: 21.4+/-11.9%), left-ventricular ejection fraction (MECC: 45.6+/-16.1%; ECC: 43.1+/-15.3%), diabetes mellitus (MECC: 14.3%; ECC: 15.1%) and COPD (MECC: 6.7%; ECC: 7.9%) did not differ between the two groups. Preoperative end-stage renal failure was an exclusion criterion. The clinical course and serological/haematological parameters in the ECC and MECC patients were compared in a retrospective manner. Although the numbers of distal anastomoses did not differ between the two groups (MECC: 3.0+/-0.9; ECC: 2.9+/-0.9), ECC time was significantly shorter in the MECC group (MECC: 96+/-33 min; ECC: 120+/-50 min, p<0.01). Creatinine kinase (CK) levels were significantly lower 6 h after surgery in the MECC group (MECC: 681+/-1505 U l(-1); ECC: 1086+/-1338 U l(-1), p<0.05) and the need of red blood cell transfusion was significantly less after MECC surgery (MECC: 3 [range: 1-6]; ECC: 5 [range: 2-9] p<0.05). Moreover, 30-day mortality was significantly lower in the MECC group as compared to the ECC group (MECC: 12.4%; ECC: 26.6, p<0.01). MECC is a safe alternative for CABG surgery. A lower 30-day mortality, lower transfusion requirements and less renal and myocardial damage encourage the use of MECC systems, especially in high-risk patients.