Hyperoxia-induced deterioration of diastolic function in anaesthetised patients with coronary artery disease - Randomised crossover trial.

Background: There are no current recommendations for oxygen titration in patients with stable coronary artery disease. This study investigates the effect of iatrogenic hyperoxia on cardiac function in patients with coronary artery disease undergoing general anaesthesia. Methods: Patients scheduled for elective coronary artery bypass graft surgery were prospectively recruited into this randomised crossover clinical trial. All patients were exposed to inspired oxygen fractions of 0.3 (normoxaemia) and 0.8 (hyperoxia) in randomised order. A transoesophageal echocardiographic imaging protocol was performed during each exposure. Primary analysis investigated changes in 3D peak strain, whereas secondary analyses investigated other systolic and diastolic responses. Results: There was no statistical difference in systolic function between normoxaemia and hyperoxia. However, the response in systolic function to hyperoxia was dependent on ventricular function at normoxaemia. Patients with a normoxaemic left ventricular (LV) global longitudinal strain (GLS) poorer than the derived cut-off (>-15.4%) improved with hyperoxia (P<0.01), whereas in patients with normoxaemic LV-GLS <-15.4%, LV-GLS worsened with transition to hyperoxia (P<0.01). The same was seen for right ventricular GLS with a cut-off at -24.1%. Diastolic function worsened during hyperoxia indicated by a significant increase of averaged E/e' (8.6 [2.6]. vs 8.2 [2.4], P=0.01) and E/A ratio (1.4 (0.4) vs 1.3 (0.4), P=0.01). Conclusions: Although the response of biventricular systolic variables is dependent on systolic function at normoxaemia, diastolic function consistently worsens under hyperoxia. In coronary artery disease, intraoperative strain analysis may offer guidance for oxygen titration. Clinical trial registration: NCT04424433.

Acid citrate dextrose formula A versus unfractionated heparin for anticoagulation of salvaged red blood cells in cardiac surgery.

Red blood cell salvage plays an important role in reducing the use of allogeneic blood transfusion during cardiac surgery. While there is consensus as to the benefit of employing cell salvage systems, there are no clear recommendations on the anticoagulant used for salvaged blood. In eight patients undergoing elective cardiac surgery at our university hospital's cardiovascular center, the authors describe hemodynamic effects of salvaged autologous blood transfusion when either unfractionated heparin or acid citrate dextrose formula A was used as the anticoagulant. Mean arterial pressure, heart rate, central venous pressure and acid-base status of the autologous red blood cell concentrate were compared between patients receiving autologous blood anticoagulated with acid citrate dextrose formula A versus unfractionated heparin. A clinically relevant decrease in mean arterial pressure (median change, - 19 mmHg [min -29; max -1] and marked acidosis [group median <6.30 [<6.30; 6.49] was observed in group acid citrate dextrose formula A. Acid citrate dextrose formula A anticoagulant for autologous red blood cell salvage has the potential to cause major adverse hemodynamic events during free-flowing re-transfusion of autologous red blood cell concentrate. Acute ionized hypocalcemia and acidemia may ensue from residual citrate in the supernatant of red blood cell concentrate reconstituted in unbuffered saline.

Study design for a randomized crossover study investigating myocardial strain analysis in patients with coronary artery disease at hyperoxia and normoxemia prior to coronary artery bypass graft surgery (StrECHO-O2).

BACKGROUND: Supplemental oxygen (O2) is used routinely during anesthesia. In the treatment of acute myocardial infarction, it has been established that hyperoxia is to be avoided, whereas information on benefit and risk of hyperoxia in patients with stable coronary artery disease (CAD) remain scarce, especially in the setting of general anesthesia. This study will compare the immediate effects of normoxemia and hyperoxia on cardiac function, with a primary focus on changes in peak longitudinal left-ventricular strain, in anesthetized stable chronic CAD patients using peri-operative transesophageal echocardiography (TEE). METHODS: A single-center randomized cross-over clinical trial will be conducted, enrolling 106 patients undergoing elective coronary artery bypass graft surgery. After the induction of anesthesia and prior to the start of surgery, cardiac function will be assessed by 2D and 3D TEE. Images will be acquired at two different oxygen states for each patient in randomized order. The fraction of inspired oxygen (FIO2) will be titrated to a normoxemic state (oxygen saturation of 95-98%) and adjusted to a hyperoxic state (FIO2 = 0.8). TEE images will be analyzed in a blinded manner for standard cardiac function and strain parameters. CONCLUSION: By using myocardial strain assessed by TEE, early and subtle signs of biventricular systolic and diastolic dysfunction can be promptly measured intraoperatively prior to the onset of severe signs of ischemia. The results may help anesthesiologists to better understand the effects of FIO2 on cardiac function and potentially tailor oxygen therapy to patients with CAD undergoing general anesthesia.

Checking the integrity of eyes in prone position: A novel application of video laryngoscopes.

Perioperative visual loss is a rare but severe complication after surgery in prone position. One of several mechanisms is direct ophthalmic compression. This can be avoided through optimal positioning and padding of the head, but position and integrity of the eyes need to be checked at regular intervals. We describe the use of a conventional video laryngoscope during vascular surgery in prone position as a simple solution for intermittent monitoring of external integrity of the eyes and size of the pupils. This requires no additional material and allows documentation of the findings. Our method might reduce complications and improve patient outcome.

Initial experiences with a centrifugal-pump based minimal invasive extracorporeal circulation system in pediatric congenital cardiac surgery.

BACKGROUND: Minimal invasive extracorporeal circulation (MiECC) circuits are an established alternative to conventional extracorporeal circulation (CECC). Based on the positive effects and improved perioperative outcomes of MiECC in adult cardiac surgery, this perfusion concept appears particularly attractive to pediatric cardiac surgery. So far, there are no reports on the clinical application of a MiECC system for corrective surgery in neonates and children. We report our initial experiences by using a MiECC system in pediatric cardiac surgery. METHODS: A total of 38 pediatric patients underwent surgical interventions for a variety of congenital heart disease from March 2017 until August 2018 with a MiECC. Following the classification of MiECC circuits by the Minimal invasive Extra-Corporeal Technologies International Society (MiECTIS), type I and type III perfusion circuits were assembled depending on the planned intervention: type I for closed heart interventions and type III for open heart procedures. Primary outcome was conversion to CECC, secondary endpoints included major adverse cardiac or cerebrovascular events (MACCE). RESULTS: MiECC perfusion was successfully performed in all patients (100%). Median patient age was 9.5 months (range, 0.2-176 months) with a median weight of 8.1 kg (range, 2.3-49 kg). For both MiECC types no system related technical complications were encountered. Beating heart procedures were performed in 23 cases (60%) at normothermia, while in 15 (40%) interventions cardioplegic cardiac arrest was induced at mild hypothermia. All patients had an uneventful perioperative course with no in-hospital mortality. MACCE did not occur during the hospitalization period. CONCLUSIONS: MiECC can be performed by using standard techniques for closed and open cardiac procedures for the correction of a variety of malformations in neonates and children with good results and uneventful postoperative course.

Late correction of tetralogy of Fallot in children.

AIM OF STUDY: To report our experience of late correction after infancy in patients with tetralogy of Fallot (ToF). METHODS: Observational single-centre retrospective analysis of the surgical techniques and perioperative development of patients from developing countries undergoing total surgical correction of ToF after infancy, between 1 November 2011 and 30 November 2016. Variables are presented as numbers with percentages or as mean ± standard deviation. Due to the setting of the humanitarian programme, clinical and echocardiographic follow-up procedures could be conducted for only one month postoperatively. RESULTS: Twenty-five children (mean age: 70.8 ± 42 months, range 23-163; 44% female) underwent total surgical correction of ToF. Two patients (0.8%) initially received a Blalock-Taussig shunt and underwent subsequent correction 24 and 108 months later, respectively. Preoperative mean right ventricular/pulmonary artery (RV/PA) gradient was 84 ± 32 mm Hg, with a Nakata index of 164 ± 71 mm2/m2. Major aortopulmonary collateral arteries (MAPCAs) were observed in eight children (32%), six (26%) of whom underwent transcatheter closure before surgery. 24 children (96%) underwent a valve-sparing pulmonary valve repair and one patient received a transannular patch (TAP). There were no cases which saw major adverse cardiac and cerebrovascular events (MACCE). Mean duration of mechanical ventilation was 28 ± 19.6 hours (range 7-76). Pre-discharge echocardiography demonstrated a mean RV/PA gradient of 25 ± 5.7 mm Hg, with left ventricular ejection fraction >60% in all cases. Overall length of hospital stay was 11.7 ± 4.5 days. There were no in-hospital mortality cases. CONCLUSIONS: Late surgical correction of ToF can be safely performed and produce highly satisfying early postoperative results comparable to those of classical “timely” correction. A valve-sparing technique can be applied in the majority of children.

Fluid management in patients undergoing cardiac surgery: effects of an acetate- versus lactate-buffered balanced infusion solution on hemodynamic stability (HEMACETAT).

BACKGROUND: Recent evidence suggests that acetate-buffered infusions result in better hemodynamic stabilization than 0.9% saline in patients undergoing major surgery. The choice of buffer in balanced crystalloid solutions may modify their hemodynamic effects. We therefore compared the inopressor requirements of Ringer's acetate and lactate for perioperative fluid management in patients undergoing cardiac surgery. METHODS: Using a randomized controlled double-blind design, we compared Ringer's acetate (RA) to Ringer's lactate (RL) with respect to the average rate of inopressor administered until postoperative hemodynamic stabilization was achieved. Secondary outcomes were the cumulative dose of inopressors, the duration of inopressor administration, the total fluid volume administered, and the changes in acid-base homeostasis. Patients undergoing elective valvular cardiac surgery were included. Patients with severe cardiac, renal, or liver disease were excluded from the study. RESULTS: Seventy-five patients were randomly allocated to the RA arm, 73 to the RL. The hemodynamic profiles were comparable between the groups. The groups did not differ with respect to the average rate of inopressors (RA 2.1 mcg/kg/h, IQR 0.5-8.1 vs. RL 1.7 mcg/kg/h, IQR 0.7-8.2, p = 0.989). Cumulative doses of inopressors and time on individual and combined inopressors did not differ between the groups. No differences were found in acid-base parameters and their evolution over time. CONCLUSION: In this study, hemodynamic profiles of patients receiving Ringer's lactate and Ringer's acetate were comparable, and the evolution of acid-base parameters was similar. These study findings should be evaluated in larger, multi-center studies. TRIAL REGISTRATION: Clinicaltrials.gov NCT02895659 . Registered 16 September 2016.

Levosimendan and systemic vascular resistance in cardiac surgery patients: a systematic review and meta-analysis.

Levosimendan is a potent non-adrenergic inodilator agent. The net effect of hemodynamic changes may result in a hyperdynamic state with low systemic vascular resistance. We conducted a systematic review and meta-analysis assessing hemodynamics in cardiac surgery patients treated with levosimendan. English-language literature was searched systematically from 2006 until October 2018, including randomized controlled trials and case-matched or retrospective studies providing at least two sequentially measured hemodynamic variables in adult patients who underwent cardiac surgery with cardiopulmonary bypass and were treated with levosimendan in comparison to alternative drugs or devices. Cardiac index significantly increased in the levosimendan group by 0.74 (0.24 to 1.23) [standardized mean difference (95% CI); p = 0.003] from baseline to postoperative day (POD) 1, and by 0.75 (0.25 to 1.25; p = 0.003) from baseline to POD 7, when corrected for the standardized mean difference at baseline by a multivariate mixed effects meta-analysis model. With this correction for baseline differences, other hemodynamic variables including systemic vascular resistance did not significantly differ until POD 1 [-0.17 (-0.64 to 0.30), p = 0.48] and POD 7 [-0.13 (-0.61 to 0.34), p = 0.58] between the levosimendan and the comparator group. Levosimendan increases cardiac index in patients undergoing cardiac surgery. Although levosimendan has inodilator properties, this meta-analysis finds no clinical evidence that levosimendan produces vasopressor-resistant vasoplegic syndrome.

Next generation viscoelasticity assays in cardiothoracic surgery: Feasibility of the TEG6s system.

BACKGROUND: Viscoelastic near-patient assays of global hemostasis have been found useful and cost-effective in perioperative settings. Shortcomings of current systems include substantial laboratory intensity, user-dependent reproducibility, relatively large sample volumes, sensitivity to ambient vibration and limited comparability between techniques and devices. The aim of this study was to assess feasibility of a new, resonance-based viscoelastic whole blood methodology (TEG6s) in cardiac surgery with cardiopulmonary bypass (CPB) and to compare the parameters this system produces with the ROTEM delta system and standard coagulation tests. METHODS: In a prospective evaluation study, twenty-three consecutive cardiac surgery patients underwent hemostasis management according to current guidelines, using the ROTEM delta system and standard coagulation tests. Blood samples were collected prior to CPB before anesthetic induction (pre-CPB), during CPB on rewarming (CPB), and 10 minutes after heparin reversal with protamine (post-CPB). ROTEM and standard coagulation test results were compared with TEG6s parameters, which were concurrently determined using its multi-channel microfluidic cartridge system. RESULTS: TEG6s provided quantifiable results pre-CPB and post-CPB, but only R (clotting time) of CKH (kaolin with heparinase) was measurable during CPB (full heparinization). Spearman's correlation coefficient (rs) was 0.78 for fibrinogen levels and MA CFF (functional fibrinogen). Correlation of several TEG6s parameters was good (0.77 to 0.91) with MCF FIBTEM, and poor (<0.56) with prothrombin time and activated partial thromboplastin time (<0.44). Rs with platelet count was moderate (0.70, MA CK; 0.73, MA CRT). Accuracy of MA CFF for detection of fibrinogen deficiency < 1.5 g/L was high (ROC-AUC 0.93). CONCLUSIONS: The TEG6s system, which is based on resonance viscoelastic methodology, appears to be feasible for POC hemostasis assessment in cardiac surgery. Its correlations with standard coagulation parameters are quite similar to those of ROTEM and there is good diagnostic accuracy for fibrinogen levels lower than 1.5 g/L. During full heparinization, TEG6s testing is limited to R measurement. Larger studies are needed to assess superiority over other POC systems.

Short-term recovery pattern of plasma fibrinogen after cardiac surgery: A prospective observational study.

Low plasma fibrinogen level is common after cardiopulmonary bypass (CPB). Current substitution practice with fibrinogen concentrate generally follows a single measurement and cut-off values from the literature, whereas early postoperative endogenous fibrinogen kinetics is incompletely described and widely disregarded. The aim of this study was to determine the short-term recovery pattern of plasma fibrinogen after CPB weaning. Our hypothesis was that in the absence of surgical bleeding, CPB-induced hypofibrinogenemia would resolve spontaneously and predictably within a few hours. In a prospective, observational study of 26 patients undergoing conventional CPB (cCPB) or minimally invasive extracorporeal circulation (MiECC), Clauss fibrinogen level (C-FIB) was determined at 10 closely spaced time points after protamine administration. Primary endpoint was the time to recovery of post-CPB fibrinogen levels to ≥1.5 g/L. C-FIB reached its nadir after protamine administration corresponding to 62 ± 5% (mean ± SD) of the baseline level after cCPB and 68 ± 7% after MiECC (p = 0.027 vs. cCPB). C-FIB recovered spontaneously at a nearly constant rate of approximately 0.08 g/L per hour. In all patients, C-FIB was ≥1.5 g/L at 4 hours and ≥2.0 g/L at 13 hours after CPB weaning. Following cardiac surgery with CPB and in the absence of surgical bleeding, spontaneous recovery of normal endogenous fibrinogen levels can be expected at a rate of 0.08 g/L per hour. Administration of fibrinogen concentrate triggered solely by a single-point measurement of low plasma fibrinogen some time after CPB is not justified.

Vertical Right Axillary Mini-Thoracotomy for Correction of Ventricular Septal Defects and Complete Atrioventricular Septal Defects.

BACKGROUND: Vertical right axillary mini-thoracotomy (VRAMT) is the standard approach for correction of atrial septal defect and partial atrioventricular septal defect at our institution. This observational single-center study compares our initial results with the VRAMT approach for the repair of ventricular septal defect (VSD) and complete atrioventricular septal defect (CAVSD) in infants and children to an approach using standard median sternotomy (MS). METHODS: The perioperative courses of patients undergoing VSD and CAVSD correction through either a VRAMT or an MS were analyzed retrospectively. The surgical technique for the VRAMT involved a 4- to 5-cm vertical incision in the right axillary fold. RESULTS: Of 84 patients, 25 (VSD, n = 15; CAVSD, n = 10) underwent correction through a VRAMT approach, whereas 59 (VSD, n = 35; CAVSD, n = 24) had repair through MS. VSD and CAVSD groups were comparable with respect to age and weight. No significant differences were observed for aortic cross-clamp duration, intensive care unit stay, hospital stay, and echocardiographic follow-up. There was no need for any conversion from VRAMT to MS in any case. Neither wound infections nor thoracic deformities were observed in both groups. CONCLUSIONS: VRAMT can be considered as a safe and effective approach for the repair of VSD and CAVSD in selected patient groups, and the outcome data appear comparable to those of MS.

Limitations of Current Near-Infrared Spectroscopy Configuration in Detecting Focal Cerebral Ischemia During Cardiac Surgery: An Observational Case-Series Study.

Cerebral oximetry using near-infrared spectroscopy (NIRS) allows for continuous monitoring of cerebral perfusion and immediate treatment of hemodynamic perturbations. In configurations used in current clinical practice, NIRS optodes are placed on the patient`s forehead and cerebral oxygen saturation (ScO2 ) is determined in bilateral frontal cortical samples. However, focal cerebral ischemic lesions outside of the NIRS field of view may remain undetected. The objective of this observational case-series study was to investigate ScO2 measurements in patients with acute iatrogenic stroke not located in the frontal cortical region. Adult patients undergoing cardiac surgery with cardiopulmonary bypass or interventional cardiology procedures and suffering stroke in the early postoperative period were identified from the Bernese Stroke Registry and analyzed for their intraoperative ScO2 values and brain imaging data. Main outcome measures were the ScO2 values, computed tomography and magnetic resonance imaging findings. In six patients, the infarct areas were localized in the vascular territories of the posterior and/or dorsal middle cerebral arteries. One patient had watershed stroke and another one excellent collaterals resulting in normal cerebral blood volume and only subtle decrease of cerebral blood flow in initially critically perfused watershed brain areas. Intraoperative ScO2 values were entirely unremarkable or nonindicative for brain damage. Our results indicate that uneventful intraoperative NIRS monitoring does not exclude severe cerebral ischemia due to the limited field of view of commercially available NIRS devices. False negative NIRS may occur as a consequence of stroke localized outside the frontal cortex.

How I manage patients with anticoagulation-associated bleeding or urgent surgery.

Antithrombotic treatment puts patients at risk of major bleeding. Fast and adequate response to anticoagulant-associated bleeding may not only stop the bleeding but prevent severe complications. However, practical treatment algorithms to guide physicians in emergency situations are lacking. Important principles that arise from management of bleeding in general are (a) implementation of an in-house algorithm, (b) rapid identification and treatment of the bleeding source, (c) adequate fluid resuscitation, (d) consideration of the application of tranexamic acid and (e) appropriate coagulation testing. We present an algorithm for anticoagulant-associated bleeding and urgent surgery, derived from available data and recommendations, and implemented at our institution. Decisions regarding reversal agents or postponing surgery are based on two questions: the occurrence of a life-threatening bleed or urgent indication for surgery, and the presence of a relevant drug level. Immediate application of reversal agents is suggested if the clinical situation is urgent and laboratory test results are delayed or unavailable. A relevant anticoagulant drug level is required in all other cases. We discuss appropriate laboratory assays for all commonly available anticoagulants, report respective target ranges or expected values, discuss time intervals before surgery, and present critical cut-off values to be used as decision criteria. Specific and unspecific reversal agents for all anticoagulants including the direct oral anticoagulants will be presented. We aim to provide practical guidance for physicians in emergency situations. In addition, we summarise and discuss available experimental and clinical data as well as recommendations provided by scientific societies, authorities and manufacturers.

Spatially extended versus frontal cerebral near-infrared spectroscopy during cardiac surgery: a case series identifying potential advantages.

Stroke due to hypoperfusion or emboli is a devastating adverse event of cardiac surgery, but early detection and treatment could protect patients from an unfavorable postoperative course. Hypoperfusion and emboli can be detected with transcranial Doppler of the middle cerebral artery (MCA). The measured blood flow velocity correlates with cerebral oxygenation determined clinically by near-infrared spectroscopy (NIRS) of the frontal cortex. We tested the potential advantage of a spatially extended NIRS in detecting critical events in three cardiac surgery patients with a whole-head fiber holder of the FOIRE-3000 continuous-wave NIRS system. Principle components analysis was performed to differentiate between global and localized hypoperfusion or ischemic territories of the middle and anterior cerebral arteries. In one patient, we detected a critical hypoperfusion of the right MCA, which was not apparent in the frontal channels but was accompanied by intra- and postoperative neurological correlates of ischemia. We conclude that spatially extended NIRS of temporal and parietal vascular territories could improve the detection of critically low cerebral perfusion. Even in severe hemispheric stroke, NIRS of the frontal lobe may remain normal because the anterior cerebral artery can be supplied by the contralateral side directly or via the anterior communicating artery.

An in vitro lung model to assess true shunt fraction by multiple inert gas elimination.

The Multiple Inert Gas Elimination Technique, based on Micropore Membrane Inlet Mass Spectrometry, (MMIMS-MIGET) has been designed as a rapid and direct method to assess the full range of ventilation-to-perfusion (V/Q) ratios. MMIMS-MIGET distributions have not been assessed in an experimental setup with predefined V/Q-distributions. We aimed (I) to construct a novel in vitro lung model (IVLM) for the simulation of predefined V/Q distributions with five gas exchange compartments and (II) to correlate shunt fractions derived from MMIMS-MIGET with preset reference shunt values of the IVLM. Five hollow-fiber membrane oxygenators switched in parallel within a closed extracorporeal oxygenation circuit were ventilated with sweep gas (V) and perfused with human red cell suspension or saline (Q). Inert gas solution was infused into the perfusion circuit of the gas exchange assembly. Sweep gas flow (V) was kept constant and reference shunt fractions (IVLM-S) were established by bypassing one or more oxygenators with perfusate flow (Q). The derived shunt fractions (MM-S) were determined using MIGET by MMIMS from the retention data. Shunt derived by MMIMS-MIGET correlated well with preset reference shunt fractions. The in vitro lung model is a convenient system for the setup of predefined true shunt fractions in validation of MMIMS-MIGET.

Cerebral Gaseous Microemboli are Detectable During Continuous Venovenous Hemodialysis in Critically Ill Patients: An Observational Pilot Study.

BACKGROUND: Continuous venovenous hemodialysis (CVVHD) may generate microemboli that cross the pulmonary circulation and reach the brain. The aim of the present study was to quantify (load per time interval) and qualify (gaseous vs. solid) cerebral microemboli (CME), detected as high-intensity transient signals, using transcranial Doppler ultrasound. MATERIALS AND METHODS: Twenty intensive care unit (ICU group) patients requiring CVVHD were examined. CME were recorded in both middle cerebral arteries for 30 minutes during CVVHD and a CVVHD-free interval. Twenty additional patients, hospitalized for orthopedic surgery, served as a non-ICU control group. Statistical analyses were performed using the Mann-Whitney U test or the Wilcoxon matched-pairs signed-rank test, followed by Bonferroni corrections for multiple comparisons. RESULTS: In the non-ICU group, 48 (14.5-169.5) (median [range]) gaseous CME were detected. In the ICU group, the 67.5 (14.5-588.5) gaseous CME detected during the CVVHD-free interval increased 5-fold to 344.5 (59-1019) during CVVHD (P<0.001). The number of solid CME was low in all groups (non-ICU group: 2 [0-5.5]; ICU group CVVHD-free interval: 1.5 [0-14.25]; ICU group during CVVHD: 7 [3-27.75]). CONCLUSIONS: This observational pilot study shows that CVVHD was associated with a higher gaseous but not solid CME burden in critically ill patients. Although the differentiation between gaseous and solid CME remains challenging, our finding may support the hypothesis of microbubble generation in the CVVHD circuit and its transpulmonary translocation toward the intracranial circulation. Importantly, the impact of gaseous and solid CME generated during CVVHD on brain integrity of critically ill patients currently remains unknown and is highly debated.

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.