Minimal Invasive Extracorporeal Circulation Research Articles

Randomized Trial of Miniaturized Versus Standard Extracorporeal Circulation in Aortic Valve Surgery

Complications related to extracorporeal circulation remain serious. Although a minimal invasive extra corporeal circulation (MiECC) system was developed to cope with these complications, its effectivity on patient-related outcomes such as blood loss remain uncertain. Therefore, the aim of this study is to compare MiECC to an advanced standard system with respect to blood loss. A total of 128 adult patients undergoing elective isolated aortic valve replacement were enrolled in a randomized clinical trial. Patients who had undergone previous heart surgery and with preexisting kidney failure were excluded. The primary end point was postoperative blood loss after 12 hours and at drain removal. Secondary end points included intensive care and total length of stay and intubation time. At 1 hour and 12 hours after surgery, clinical laboratory data were determined. Early clinical outcomes and long-term survival were determined. MiECC patients (n= 63) had a significant lower blood loss (230 mL, 95% confidence interval: 203 to 261 mL) than regular patients (n= 62) after 12 hours (288 mL, 95% confidence interval: 241 to 344 mL, p= 0.04). A preservation of hemoglobin levels 1 hour and 12 hours after surgery in the MiECC group were observed (p < 0.001). No difference was found in early clinical outcomes and long-term survival. This randomized controlled trial compares MiECC and an advanced system for aortic valve replacement with blood loss as primary end point. We conclude that using MiECC is clinically equal for short- and long-term follow-up regarding blood loss. NTR3378.

Hemodynamic energy during pulsatile extracorporeal circulation using flexible and rigid arterial tubing: a reassessment

Pulsatile extracorporeal circulation may improve organ perfusion during cardiac surgery. Some minimally invasive extracorporeal circulation (MiECC) systems allow pulsatile perfusion. The present study investigated the influence of arterial tubing compliance on hemodynamic energy transfer into the patient. Aortic models with adult human geometry were perfused in a mock circulation. A MiECC system was connected using either high-compliance silicone tubing or standard kit tubing. Energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE) were computed from flow and pressure data. Aortic models with physiological and sub-physiological compliance were tested to assess the influence of the pseudo-patient. Non-pulsatile flow did not generate SHE. SHE during pulsatile flow in the compliant aortic model was significantly higher with kit tubing compared to silicone tubing. Maximum SHE was achieved at 1.6 L/min with kit tubing (7.7% of mean arterial pressure) and with silicone tubing (4.9%). Using the low-compliance aortic model, SHE with kit tubing reached a higher maximum of 14.2% at 1.8 L/min compared to silicone tubing (11.8% at 1.5 L/min). Flexible arterial tubing did not preserve more hemodynamic energy from a pulsatile pump compared to standard kit tubing in a model of adult extracorporeal circulation. The pseudo-patient's compliance significantly affected the properties of the mock circulation.

OC06 BUILDING UP A MULTIDISCIPLINARY 360° MINIMALLY INVASIVE PROGRAM FOR AVR: OUR EXPERIENCE

Aim: The aim of this study was to report the first results of our multidisciplinary minimally invasive program to treat patients who require aortic valve replacement (AVR), which involves: 1) reduced chest incision (through upper ministernotomy or right anterior minithoracotomy), 2) sutureless or rapid deployment AVR, 3) minimally invasive extracorporeal circulation (MiECC) system and 4) ultra fast-track (UFT) anaesthesia. Methods: Data from 167 consecutive patients undergoing primary isolated aortic valve replacement through minimally invasive approaches (MIAVR) between October 2016 and April 2018 were prospectively collected. The mean age of the study population was 74 ± 9 years, and the average EuroSCORE II was 2.1 ± 1.2. Results: MIAVR was performed using sutureless or rapid deployment valves in 76 (45.5%) patients, MiECC system in 63 (37.7%), and UFT management in 67 (40.1%). Overall in-hospital mortality was 0.6% (n = 1). The rate of postoperative stroke and atrioventricular block requiring pacemaker implantation was 1.2% (n = 2) and 3.6% (n = 6), respectively. MiECC system was associated with reduced postoperative bleeding (requiring chest re-opening) compared with conventional cardio-pulmonary bypass circuits (0% vs. 5.8%, p = 0.05). The mean intensive care unit stay was 25 hours in UFT patients and 52.2 hours in no-UFT patients (p = 0.04). Hospital stay was similar between groups (UFT 6.9 days, no-UFT 13.9 days, p = 0.2). Conclusions: Our UFT mini AVR program is a multidisciplinary minimally approach that involves the latest best technologies and techniques for AVR. We believe it may considerably increase patient's comfort being associated with faster recovery and excellent hospital outcomes.

Prospective, Randomized Un-Blinded Three Arm Controlled Study in Coronary Artery Revascularization with Minimal Invasive Extracorporeal Circulation Systems (MiECC): Surrogate Parameter Analysis of Biocompatibility.

Minimal extracorporeal circulation techniques and systems (MiECC) may reduce the negative side effects of conventional extracorporeal circulation (ECC). However, it is still unclear as to what this is caused by, the reduced priming volume and hemodilution, or the avoidance of blood-air contact and dispersion of mediastinal debris into the systemic circulation. The aim of the trial was the comparison of MiECC to an open ECC setup (openECC) or a system with reduced blood air and debris interaction (closeECC).Methods: In a prospective randomized trial, 72 patients (73 ± 5.3 years; 83% male) referred for coronary artery bypass graft (CABG) were randomly assigned either to MiECC (priming volume 550mL), closeECC, or openECC (priming volume 1250mL). The laboratory surrogate endpoints (renal function, inflammatory response, ischemia, coagulation, and hemolysis) and clinical data were measured at six different time points (T1-6).Results: Patients were comparable for all preoperative variables. The operation times (MiECC 261 ± 79min; openECC 264 ± 75min; closeECC 231 ± 68min) and perfusion times (MiECC 115 ± 49min; openECC353 107 ± 37min; closeECC 99 ± 22min) revealed a trend of faster performance in the closeECC group (P < .05). Pro-inflammatory cytokines, ischemia, and coagulation markers were significantly elevated postoperatively in all cardiopulmonary bypass types, and decreased to pre-baseline levels at discharge (T5) without identifiable statistical differences between the three study groups. Free-hemoglobin was not significantly increased by centrifugal pump or cell saver procedures. Significant intraoperative hemodilution effects due to the different priming volumes were demonstrated only at the end of operation (T2) (MiECC Hb 9.6 ± 1.1g/dL; openECC Hb 9.0 ± 0.8g/dL; closeECC Hb 8.7 ± 1g/dL; P =. 01). Neither the hemodilution, suction technique (MiECC), nor blood-air interface (closeECC) could show sustainable benefits in this underpowered study, compared to conventional ECC systems (openECC) in a high volume series of surrogate parameters.

Ultra fast-track minimally invasive aortic valve replacement: going beyond reduced incisions.

Aortic valve replacement (AVR) via a median sternotomy approach has been largely reported to be safe and long-term efficacious, and currently represents the 'gold standard' approach for aortic stenosis treatment. However, aortic valve surgery has undergone continuous development over the last years, involving less invasive techniques and new technologies to reduce the traumatic impact of the intervention and extend the operability toward increasingly high-risk patients. Indeed, minimally invasive AVR and transcatheter aortic valve replacement caseload have steadily increased leading to a paradigm shift in the treatment of aortic valve disease. In this setting, we have established a multidisciplinary minimally invasive programme to treat patients who require AVR. Herein, we present our approach including (i) reduced chest incision (through a J ministernotomy), aiming to reduce the traumatic impact of the surgical procedure, to decrease blood loss, postoperative pain and wound complications and to increase patient's satisfaction; (ii) rapid-deployment AVR, to reduce operative times, to facilitate minimally invasive approach and to improve haemodynamic outcomes; (iii) minimal invasive extracorporeal circulation system, to improve end-organ protection, to decrease systemic inflammatory response and to promote fast-track anaesthesia and (iv) ultra fast-track anaesthesia, to decrease the rate of postoperative complications and assure better and earlier recovery.

Shed-blood-separation and cell-saver: an integral Part of MiECC? Shed-blood-separation and its influence on the perioperative inflammatory response during coronary revascularization with minimal invasive extracorporeal circulation systems - a randomized controlled trial.

The postoperative systemic inflammatory response after cardiopulmonary bypass (CPB) is still an undesirable side-effect after cardiac surgery. It is most likely caused by blood contact with foreign surfaces and by the surgical trauma itself. However, the recirculation of activated shed mediastinal blood is another main cause of blood cell activation and cytokine release. Minimal invasive extracorporeal circulation (MiECC) comprises a completely closed circuit, coated surfaces and the separation of suction blood. We hypothesized that MiECC, with separated cell saved blood, would induce less of a systemic inflammatory response than MiECC with no cell-saver. The aim of this study was, therefore, to investigate the impact of cell washing shed blood from the operating field versus direct return to the ECC on the biomarkers for systemic inflammation. In the study, patients with MiECC and cell-saver were compared with the control group, patients with MiECC and direct re-transfusion of the drawn blood shed from the surgical field. High amounts of TNF-α (+ 120% compared to serum blood) were found in the shed blood itself, but a significant reduction was demonstrated with the use of a cell-saver (TNF-α ng/l post-ECC 10 min: 9.5±3.5 vs. 19.7±14.5, p<0.0001). The values for procalcitonin were not significantly increased in the control group (6h: 1.07±3.4 vs. 2.15±9.55, p=0.19) and lower for C-reactive protein (CRP) (24h: 147.1±64.0 vs.134.4±52.4 p=0.28). The use of a cell-saver and the processing of shed blood as an integral part of MiECC significantly reduces the systemic cytokine load. We, therefore, recommend the integration of cell-saving devices in MiECC to reduce the perioperative inflammatory response.

A multidisciplinary perioperative strategy for attaining "more physiologic" cardiac surgery.

Cardiac surgery is, by definition, a "non-physiologic" intervention associated with systemic adverse effects. Despite advances in surgical technique, cardiopulmonary bypass (CPB) technology as well as anaesthesia management and patient care, there is still significant morbidity and subsequent mortality. We consider that the contemporary demand for further improving patient outcome mandates the upgrade from optimal perfusion during the procedure as the gold standard to the concept of a "more physiologic" cardiac surgery. Our policy is a multidisciplinary perioperative strategy based on goal-directed perfusion throughout surgery incorporating in-line monitoring. This translates to "prevent rather than correct" malperfusion through real-time adjustment rather than correction of derangement detected late by incremental evaluation. The strategy is based on continuous monitoring of cardiac index, SvO2, DO2i, DO2i/VCO2i and rSO2. Data acquisition is followed by action when needed; this includes stepwise: transfusion, increase of cardiac output and initiation of inotropic/vasoactive support. Moreover, implementation of minimally invasive extracorporeal circulation (MiECC) is considered as a fundamental component of physiologic perfusion when on-CPB, providing improved circulatory support and end-organ protection. We consider that, with this strategy which establishes optimal perfusion perioperatively, we attain the goal of a "more physiologic" cardiac surgery.

Minimal Invasive Extracorporeal Circulation (MIECC) and the Role of Shed Blood Separation on the Inflammation-Process after CABG Surgery

Minimal Invasive Extracorporeal Circulation (MIECC) and the Role of Shed Blood Separation on the Inflammation-Process after CABG Surgery

Quantification of Operational Learning in Minimal Invasive Extracorporeal Circulation.

Minimal invasive extracorporeal circulation (MiECC) has initiated important new efforts within science and technology towards a more physiologic perfusion. In this study, we aim to investigate the learning curve of our center regarding MiECC. We studied a series of 150 consecutive patients who underwent elective coronary artery bypass grafting by the same surgical team during the initial phase of MiECC application. Patients were randomly assigned into two groups. Group A (n = 75) included patients operated on MiECC, while group B (n = 75) included patients operated with conventional cardiopulmonary bypass (cCPB). The primary end-point of the study was to identify whether there is a learning curve when operating on MiECC. The following parameters were unrelated with increasing experience, even though the results favored MiECC use: reduced CPB duration (102.9 ± 25 vs. 122.2 ± 33 min, P <0.001), peak troponin release (0.07 ± 0.02 vs. 0.1 ± 0.04 ng/mL, P < 0.01), peak creatinine levels (0.97 ± 0.24 vs. 1.2 ± 0.3 mg/dL, P < 0.001), duration of mechanical ventilation (14.1 ± 7.2 vs. 36.9 ± 59.8 h, P < 0.01) and ICU stay (2.1 ± 0.7 vs. 4.4 ± 6.4 days, P < 0.01). However, need for intraoperative blood transfusion showed a trend towards a gradual decrease as experience with MiECC system was accumulating (R2 = 0.094, P = 0.007). Subsequently, operational learning applied to postoperative hematocrit and hemoglobin levels (R2 = 0.098, P = 0.006). We identified that advantages of MiECC technology in terms of reduced hemodilution and improved end-organ protection and clinical outcome are evident from the first patient. Optimal results are obtained with 50 cases; this refers mainly to significant reduction in the need for intraoperative blood transfusion. Teamwork from surgeons, anesthesiologists, and perfusionists is of paramount importance in order to maximize the clinical benefits from this technology.

Minimally invasive extracorporeal circulation improves quality of life after coronary artery bypass grafting.

The effect on postoperative health-related quality of life (HRQoL) after coronary artery bypass grafting (CABG) surgery with conventional cardiopulmonary bypass (cCPB) and off-pump surgery has been investigated extensively; however, there are no studies focusing on HRQoL after surgery with minimally invasive extracorporeal circulation (MiECC). Therefore, we sought to prospectively investigate the effect of MiECC on postoperative HRQoL when compared with cCPB in patients undergoing CABG over a short-term (3-month) follow-up period. Sixty patients scheduled for elective CABG surgery were randomly assigned into two groups: those who had surgery on MiECC system (n = 30) and those who underwent CABG using cCPB (n = 30). Quality-of-life assessment was performed preoperatively (baseline-T0), at first postoperative month (T1) and at 3-month follow-up (T3). The RAND SF-36 scale was used for data collection, which included both sociodemographic and clinical characteristics of patients. The primary outcome of the study was quantitative measurement of postoperative HRQoL at 3-month follow-up. Both groups were balanced in terms of demographic, socio-economic and operative characteristics. At 3-month follow-up, mean SF-36 component and summary scores in each group were higher in absolute values than the respective mean baseline scores, apart from role-physical score in patients operated with cCPB. Patients operated on MiECC showed uniformly significantly higher values in all individual and summary domains, whereas patients operated on cCPB showed significant improvement in 6/8 individual domains. Patients operated on MiECC showed a more pronounced increase in SF-36 individual domain scores from the first to the third postoperative month when compared with cCPB, which was statistically significant regarding physical functioning (P = 0.001), role-physical (P < 0.001), vitality (P = 0.01) and role-emotional (P = 0.004). This resulted in a significant improvement in physical (P = 0.002) and mental (P = 0.01) summary scores. The current study proves that MiECC significantly improves HRQoL after coronary surgery compared with cCPB. This finding, combined with results from large-scale studies showing superior clinical outcomes from its use, enhances the role of MiECC as a dominant technique in coronary revascularization surgery.

Cerebral Microembolization During Aortic Valve Replacement Using Minimally Invasive or Conventional Extracorporeal Circulation: A Randomized Trial.

To compare intraoperative cerebral microembolic load between minimally invasive extracorporeal circulation (MiECC) and conventional extracorporeal circulation (CECC) during isolated surgical aortic valve replacement (SAVR), we conducted a randomized trial in patients undergoing primary elective SAVR at a tertiary referral hospital. The primary outcome was the procedural phase-related rate of high-intensity transient signals (HITS) on transcranial Doppler ultrasound. HITS rate was used as a surrogate of cerebral microembolism in pre-defined procedural phases in SAVR using MiECC or CECC with (+F) or without (-F) an oxygenator with integrated arterial filter. Forty-eight patients were randomized in a 1:1 ratio to MiECC or CECC. Due to intraprocedural Doppler signal loss (n = 3), 45 patients were included in final analysis. MiECC perfusion regimen showed a significantly increased HITS rate compared to CECC (by a factor of 1.75; 95% confidence interval, 1.19-2.56). This was due to different HITS rates in procedural phases from aortic cross-clamping until declamping [phase 4] (P = 0.01), and from aortic declamping until stop of extracorporeal perfusion [phase 5] (P = 0.05). Post hoc analysis revealed that MiECC-F generated a higher HITS rate than CECC+F (P = 0.005), CECC-F (P = 0.05) in phase 4, and CECC-F (P = 0.03) in phase 5, respectively. In open-heart surgery, MiECC is not superior to CECC with regard to gaseous cerebral microembolism. When using MiECC for SAVR, the use of oxygenators with integrated arterial line filter appears highly advisable. Only with this precaution, MiECC confers a cerebral microembolic load comparable to CECC during this type of open heart surgery.

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.

Minimal invasive extracorporeal circulation should become the standard practice in coronary revascularization surgery

We read with great interest the large-scale network meta-analysis by Kowalewski et al. comparing clinical outcomes of patients undergoing coronary artery bypass grafting (CABG) operated on using minimal invasive extracorporeal circulation (MiECC) or off-pump (OPCAB) with those undergoing surgery on conventional cardiopulmonary bypass (CPB) [1]. The authors actually integrated into single study two recently published meta-analysis comparing MiECC and OPCAB with conventional CPB, respectively [2, 3] into a single study. According to the results of this study, MiECC and OPCAB are both strongly associated with improved perioperative outcomes following CABG when compared with CABG performed on conventional CPB. The authors conclude that MiECC may represent an attractive compromise between OPCAB and conventional CPB. After carefully reading the whole manuscript, it becomes evident that the role of MiECC is clearly undervalued. Detailed statistical analysis using the surface under the cumulative ranking probabilities indicated that MiECC represented the safer and more effective intervention regarding all-cause mortality and protection from myocardial infarction, cerebral stroke, postoperative atrial fibrillation and renal dysfunction when compared with OPCAB. Even though no significant statistical differences were demonstrated between MiECC and OPCAB, the superiority of MiECC is obvious by the hierarchy of treatments in the probability analysis, which ranked MiECC as the first treatment followed by OPCAB and conventional CPB. Thus, MiECC does not represent a compromise between OPCAB and conventional CPB, but an attractive dominant technique in CABG surgery. These results are consistent with the largest published meta-analysis by Anastasiadis et al. comparing MiECC versus conventional CPB including a total of 2770 patients. A significant decrease in mortality was observed when MiECC was used, which was also associated with reduced risk of postoperative myocardial infarction and neurological events [4]. Similarly, another recent meta-analysis by Benedetto et al. compared MiECC versus OPCAB and resulted in comparable outcomes between these two surgical techniques [5]. As stated in the text, superiority of MiECC observed in the current network meta-analysis, when compared with OPCAB, could be attributed to the fact that MiECC offers the potential for complete revascularization, whereas OPCAB poses a challenge for unexperienced surgeons; especially when distal marginal branches on the lateral and/or posterior wall of the heart need revascularization. This is reflected by a significantly lower number of distal anastomoses performed in OPCAB when compared with conventional CPB. Therefore, taking into consideration the literature published up to date, including the results of the current article, we advocate that MiECC should be integrated in the clinical practice guidelines as a state-of-the-art technique and become a standard practice for perfusion in coronary revascularization surgery.

Use of minimal invasive extracorporeal circulation in cardiac surgery: principles, definitions and potential benefits. A position paper from the Minimal invasive Extra-Corporeal Technologies international Society (MiECTiS).

Minimal invasive extracorporeal circulation (MiECC) systems have initiated important efforts within science and technology to further improve the biocompatibility of cardiopulmonary bypass components to minimize the adverse effects and improve end-organ protection. The Minimal invasive Extra-Corporeal Technologies international Society was founded to create an international forum for the exchange of ideas on clinical application and research of minimal invasive extracorporeal circulation technology. The present work is a consensus document developed to standardize the terminology and the definition of minimal invasive extracorporeal circulation technology as well as to provide recommendations for the clinical practice. The goal of this manuscript is to promote the use of MiECC systems into clinical practice as a multidisciplinary strategy involving cardiac surgeons, anaesthesiologists and perfusionists.

Modular minimally invasive extracorporeal circulation systems; can they become the standard practice for performing cardiac surgery?

Minimally invasive extracorporeal circulation (MiECC) has been developed in an attempt to integrate all advances in cardiopulmonary bypass technology in one closed circuit that shows improved biocompatibility and minimizes the systemic detrimental effects of CPB. Despite well-evidenced clinical advantages, penetration of MiECC technology into clinical practice is hampered by concerns raised by perfusionists and surgeons regarding air handling together with blood and volume management during CPB. We designed a modular MiECC circuit, bearing an accessory circuit for immediate transition to an open system that can be used in every adult cardiac surgical procedure, offering enhanced safety features. We challenged this modular circuit in a series of 50 consecutive patients. Our results showed that the modular AHEPA circuit design offers 100% technical success rate in a cohort of random, high-risk patients who underwent complex procedures, including reoperation and valve and aortic surgery, together with emergency cases. This pilot study applies to the real world and prompts for further evaluation of modular MiECC systems through multicentre trials.

Minimal invasive Extra-Corporeal Circulation (MiECC): a revolutionary evolution in perfusion.

Since the beginning of extracorporeal circulation (ECC) in cardiac surgery, a multitude of changes and improvements were aimed to reduce the adverse systemic effects caused by the artificial surfaces of the perfusion circuit. The clinical picture is similar to a systemic inflammatory response syndrome [1]. The magnitude of the inflammatory response adversely influences clinical outcomes [2]. Hence, the overall morbidity associated with cardiac surgery is substantial [3]. The off-pump coronary artery bypass (OPCAB) technique was introduced as a strategy to decrease the side effects of cardiopulmonary bypass (CPB). But the real advantages of OPCAB have been questioned in recent years [4]. In the early 2000s, a simplified perfusion system comprising all technological advancements was designed [5]. The modifications of the new system were much more revolutionary than the individual improvements to the existing conventional CPB circuits. The idea was to create a system including all established benefits in one CPB set-up. The Minimal Extra-Corporeal Circulation (MiECC) technology was born. Since then, MiECC systems have been developed to increase the technical ease of on-pump surgery while tempering its disadvantages. For many years, cardiac surgeons, anaesthesiologists and perfusionists considered MiECC systems as a miniaturization or simplification of traditional CPB only. MiECC significantly attenuated morbidity attributed to conventional ECC, as for beatingheart procedures, while permitting optimal technical surgical conditions [6]. ‘The authors believe that MiECC technology represents more than a miniaturization process: it is a major step forward and a totally new philosophy to be integrated in contemporary cardiac surgery’. The idea of MiECC systems has initiated new efforts to improve the biocompatibility of CPB systems and minimize their side effects, offering finally better postoperative end-organ function. Characteristics of MiECC include the following: (1) a blood pump with optimal biocompatibility, low thrombogenicity, minimal haemolysis and activation of leucocytes as well as proinflammtory mediators; (2) a minimal tubing length to reduce the priming volume required and thus minimize haemodilution, decreasing the need for foreign blood transfusions; (3) coated surfaces to reduce protein adsorption and platelet activation; (4) separation of shed blood and exclusion of activated blood components via cell salvage; (5) closed system to avoid blood–air contact; (6) temperature management depending on the need and magnitude of surgery should be possible; (7) use of modern concepts of myocardial protection, like blood cardioplegia, must be easy to integrate; (8) safe de-airing must be possible following open heart procedures; (9) finally, it should help modern concepts of fast-track anaesthesia [7, 8]. These characteristics will help to make MiECC an element of a minimal invasive procedure rather than simply a miniaturized CPB system. Numerous randomized clinical studies have proved that MiECC exerts significant beneficial effects on postoperative morbidity, by reducing haemodilution, mediastinal bleeding, need for blood transfusion and inflammatory response. Clinical benefits are: improved end-organ (myocardial, renal and cerebral) protection and reduction of the length of intensive care unit stay [5–8]. Moreover, it is associated with a significant survival benefit in coronary procedures compared with conventional ECC as shown in a recent meta-analysis. This analysis reported randomized trials including 24 studies with a total of 2770 patients [9] and provided a Scientific Class I, Level of evidence A for implementation of MiECC, at least for coronary revascularization. Despite these clear clinical advantages, penetration of the MiECC technology into clinical practice remains significantly low. Thus, the authors took the initiative to organize the ‘1st International Symposium on Minimal invasive Extracorporeal Circulation Technologies (1st MiECT)’ in Thessaloniki, Greece during June 13–14 to create a dedicated international forum to stimulate the exchange of ideas in clinical application and research in the field of Minimal invasive Extracorporeal Circulation Technology without geographical bias (www.miect.org). More than 400 participants from all continents registered. Beside scientific sessions, wet-labs with two simulators for ‘hands-on training’ allowed participants to practice on all commercially available MiECC systems. Twenty abstracts were selected for publication and are part of this Interactive Cardiovascular and Thoracic Surgery issue. During the congress, the ‘Minimal invasive Feedback from the 1st International Symposium on Minimal invasive Extracorporeal Circulation Technologies, Thessaloniki, Greece, 13–14 June 2014.

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.

Severe systemic inflammation response syndrome after minimal invasive extracorporeal circulation

Minimal extracorporeal circulation (MECC) systems were developed to minimise patients’ risks associated with cardiopulmonary bypass (CPB) for cardiac surgery. Common side effects of conventional CPB are haemodilution, myocardial cell damage, lung dysfunction, micro-embolic events and systemic inflammatory response syndrome [1–3]. With MECC, reduced foreign surface and lack of blood-air interface in the open hard-shelled reservoir are thought to result in decreased inflammatory side effects of CPB. Recently, a 78 year-old man with coronary artery disease was scheduled for coronary artery bypass grafting with a MECC (Firma, Stadt, Land) in our institution. Body weight was 78 kg, left ventricular function was normal and there were no severe concurrent diseases or abnormal laboratory values. MECC was performed with the standard pump flow used in our institution of 2.5 l.min−1.m−2 under normothermic conditions. Total time on MECC was 105 min and time of aortic cross clamping was 71 min. Anaesthesia and surgery were performed uneventfully until release of the aortic clamp. Ten minutes after declamping, mean arterial pressure decreased profoundly to 30 mmHg. Norepinephrine was repeatedly given for stabilisation of blood pressure. After weaning from MECC, norepinephrine (cumulative dose 350 μg within the first 40 min) and 1500 ml hydroxyethylstarch were given to stabilise mean arterial pressure at approximately 60 mmHg. Subsequently, a continuous infusion of norepinephrine was started with 0.10 μg.kg−1.min−1. Systemic vascular resistance 1 h postoperatively was markedly reduced at 500 dyne.sec−1.cm−5. Forty minutes following separation from MECC, laboratory tests showed a marked drop in platelet count (47 × 103 μl−1), a decreased international normalised ratio of 2.02 and an increased partial thromboplastin time (71 s). Due to severe diffuse bleeding, eight units of packed red cells, 14 units of fresh frozen plasma and five units of packed platelets were transfused. 1250 IU recombinant factor VIIa were administered as the patient continued to bleed. Coagulation parameters normalised after this therapy in the first 3 h postoperatively. The lowest postoperative leucocyte count was 2.27 × 103 μl−1, and serum level of interleukin 6 was above the upper range. After appropriate therapy, the patient was discharged from the intensive care unit at the second postoperative day and left the hospital 6 days later in good condition. Currently there are no reports of severe inflammatory reaction or bleeding disorder following a MECC procedure. In the case presented, a patient without known bleeding disorder or other concurrent diseases underwent coronary artery bypass grafting with MECC. Both the bleeding disorder and the observed vasodilatation were likely to be symptoms of a severe systemic inflammatory response syndrome induced by the MECC. This is suggested by the elevated level of interleukin 6 and the low leukocyte count that are usually observed during systemic inflammatory response syndrome. Since the patient had neither a history of bleeding disorder nor known allergic disposition, the development of these severe complications can probably attributed to the extracorporeal circulation itself.