Perfusion quality odds (PEQUOD) trial: validation of the multifactorial dynamic perfusion index as a predictor of cardiac surgery-associated acute kidney injury

OBJECTIVES

The multifactorial dynamic perfusion index was recently introduced as a predictor of cardiac surgery-associated acute kidney injury. The multifactorial dynamic perfusion index was developed based on retrospective data retrieved from the patient files. The present study aims to prospectively validate this index in an external series of patients, through an on-line measure of its various components.

METHODS

Inclusion criteria were adult patients undergoing cardiac surgery with cardiopulmonary bypass. Data collection included preoperative factors and cardiopulmonary bypass-related factors. These were collected on-line using a dedicated monitor. Factors composing the multifactorial dynamic perfusion index are the nadir haematocrit, the nadir oxygen delivery, the time of exposure to a low oxygen delivery, the nadir mean arterial pressure, cardiopulmonary bypass duration, the use of red blood cell transfusions and the peak arterial lactates.

RESULTS

Two hundred adult patients were investigated. The multifactorial dynamic perfusion index had a good (c-statistics 0.81) discrimination for cardiac surgery-associated acute kidney injury (any stage) and an excellent (c-statistics 0.93) discrimination for severe patterns (stage 2-3). Calibration was modest for cardiac surgery-associated acute kidney injury (any stage) and good for stage 2-3. The use of vasoconstrictors was an additional factor associated with cardiac surgery-associated acute kidney injury.

CONCLUSIONS

The multifactorial dynamic perfusion index is validated for discrimination of cardiac surgery-associated acute kidney injury risk. It incorporates modifiable risk factors, and may help in reducing the occurrence of cardiac surgery-associated acute kidney injury.

Plasma-Free Strategy for Cardiac Surgery with Cardiopulmonary Bypass in Infants < 10 kg: A Retrospective, Propensity-Matched Study

BACKGROUND

Infants < 10 kg undergoing cardiac surgery with cardiopulmonary bypass (CPB) may receive either fresh frozen plasma (FFP) or other solutions in the CPB priming volume. The existing comparative studies are controversial. No study addressed the possibility of total avoidance of FFP throughout the whole perioperative course in this patient population. This retrospective, non-inferiority, propensity-matched study investigates an FFP-free strategy compared to an FFP-based strategy.

METHODS

Among patients <10 kg with available viscoelastic measurements, 18 patients who received a total FFP-free strategy were compared to 27 patients (1:1.5 propensity matching) receiving an FFP-based strategy. The primary endpoint was chest drain blood loss in the first 24 postoperative hours. The level of non-inferiority was settled at a difference of 5 mL/kg.

RESULTS

The 24-h chest drain blood loss difference between groups was -7.7 mL (95% confidence interval -20.8 to 5.3) in favor of the FFP-based group, and the non-inferiority hypothesis was rejected. The main difference in coagulation profile was a lower level of fibrinogen concentration and FIBTEM maximum clot firmness in the FFP-free group immediately after protamine, at the admission in the ICU and for 48 postoperative hours. No differences in transfusion of red blood cells or platelet concentrate were observed; patients in the FFP-free group did not receive FFP but required a larger dose of fibrinogen concentrate and prothrombin complex concentrate.

CONCLUSIONS

An FFP-free strategy in infants < 10 kg operated with CPB is technically feasible but results in an early post-CPB coagulopathy that was not completely compensated with our bleeding management protocol.

Clopidogrel Resistance and Ticagrelor Replacement in Dual Antiplatelet Therapy for Carotid Artery Stenting

BACKGROUNDS

Resistance to the pharmacological effect of clopidogrel in patients undergoing dual antiplatelet therapy for carotid stenting may increase the risk of periprocedural neurological events. The purpose of the study was to describe the phenomenon of clopidogrel resistance in a series of patients undergoing carotid stenting.

METHODS

Data of patients who consecutively underwent carotid stenting from November 2016 to December 2020 for a significant stenosis and who underwent a dual antiplatelet therapy using acetyl-salicylic acid and clopidogrel were prospectively collected. Patients who were already taking a different thienopyridine were excluded. The effectiveness of antiplatelet drugs was assessed by the impedance aggregometry test. Primary endpoint was to evaluate the incidence of clopidogrel resistance and the effectiveness of ticagrelor as alternative therapy. P values < 0.05 were considered statistically significant.

RESULTS

Two-hundred patients (80 females, 40%) underwent stenting for carotid stenosis (94% asymptomatic). The phenomenon of clopidogrel resistance was observed in 38 patients (19%), in whom clopidogrel was replaced by ticagrelor (90 mg/bis in die) with 100% effectiveness at aggregometry test. Platelet counts was associated to clopidogrel resistance (P = 0.001). There was no stent thrombosis at 30 days, neither major hemorrhagic events; a total of 12/200 major adverse cardiovascular events occurred (6%), including 1 in the group of patients who took ticagrelor and 11 in group of patients under clopidogrel (2.6% versus 6.7%, P = 0.55).

CONCLUSIONS

Clopidogrel was ineffective in 19% of patients undergoing carotid stenting. Platelet count seemed to affect this phenomenon. In these patients, clopidogrel was effectively replaced by ticagrelor.

The Very Long COVID: Persistence of Symptoms after 12-18 Months from the Onset of Infection and Hospitalization

According to the World Health Organization's definition, long COVID is the persistence or development of new symptoms 3 months after the initial infection. Various conditions have been explored in studies with up to one-year follow-up but very few looked further. This prospective cohort study addresses the presence of a wide spectrum of symptoms in 121 patients hospitalized during the acute phase of COVID-19 infection, and the association between factors related to the acute phase of the disease and the presence of residual symptoms after one year or longer from hospitalization. The main results are as follows: (i) post-COVID symptoms persist in up to 60% of the patient population at a mean follow-up of 17 months; (ii) the most frequent symptoms are fatigue and dyspnea, but neuropsychological disturbances persist in about 30% of the patients (iii) when corrected for the duration of follow-up with a freedom-from-event analysis; only complete (2 doses) vaccination at the time of hospital admission remained independently associated with persistence of the major physical symptoms, while vaccination and previous neuropsychological symptoms remained independently associated with persistence of major neuropsychological symptoms.

The Rise and Fall of Antithrombin Supplementation in Cardiac Surgery

Various cohort studies, both retrospective and prospective, showed that low antithrombin levels after cardiac surgery (at the arrival in the intensive care unit and during the next days) were associated with a number of adverse outcomes, including surgical reexploration and thromboembolic events, eventually leading to prolonged stay in the intensive care. Values lower than 58% to 64% of antithrombin activity were indicative of this higher morbidity with good sensitivity and specificity. The scenario generated the hypothesis that low antithrombin levels needed to be corrected by supplementation to improve postoperative outcome. However, randomized controlled studies run to test this idea failed to demonstrate any benefit of antithrombin supplementation, showing no effects on outcome, neither as preemptive preoperative strategy nor for treating postoperative low antithrombin values. In addition, randomized trials highlighted that those patients who received antithrombin experienced significantly higher incidence of acute kidney injury with a pooled odds ratio of 4.41 (95% CI, 1.90-10.23; P = .001). A strongly decreased thrombin activity after antithrombin correction may eventually affect the efficiency of the glomerular filtration and cause the deterioration of kidney function, but underlying biological mechanisms remain unclear. In conclusion, low levels of antithrombin activity after cardiac surgery should be considered as a marker of greater severity of the patient's conditions and/or of the complexity of the surgical procedure. There are no indications for antithrombin supplementation in cardiac surgery unless for correcting heparin resistance.

Are Viscoelastic Tests Clinically Useful to Identify Platelet-Dependent Bleeding in High-Risk Cardiac Surgery Patients?

BACKGROUND

Postoperative use of platelet function testing to rule out microvascular bleeding due to platelet dysfunction after cardiac surgery still lacks strong reference data and reliable cutoff values, yielding a clinically adequate sensitivity and specificity. The present study aims to investigate the performance of two different point-of-care viscoelastic devices and platelet aggregometry in expressing surgery-dependent platelet dysfunction and anticipating postoperative major bleeding in a cohort of high-risk patients.

METHODS

Prospective cohort study of 50 adult patients who were on antiplatelet drugs discontinued for no more than 7 days (clopidogrel and prasugrel) or 5 days (ticagrelor) undergoing cardiac surgery with cardiopulmonary bypass (CPB). Coagulation and platelet function testing, including QUANTRA, ROTEM, and Multiplate, were assessed preoperatively and postoperatively. Chest drain blood loss was measured in the first 12 postoperative hours. Perioperative bleeding was assessed using a modified version of the Universal Definition of Perioperative Bleeding (UDPB) in cardiac surgery, modified to not consider anemia-correcting packed red cells transfusions in the absence of bleeding >600 mL/12 h. Major bleeding was identified as UDPB class II or higher.

RESULTS

Multiplate adenosine diphosphate (ADPtest) was significantly ( P = .001) reduced after CPB, whereas TRAPtest was not. The platelet component (PC) as extrapolated by ROTEM data (EXTEM MCF-FIBTEM MCF) was unchanged after CPB, while the A10 PC (PC at 10 minutes) was significantly ( P = .001) reduced. The QUANTRA platelet contribution to clot stiffness (PCS) was significantly ( P = .001) reduced, as well. At the ROC analysis for the predictive ability of the post-CPB platelet function testing, the best discrimination was obtained by the QUANTRA PCS, with an area under the curve (AUC) (95% confidence interval [CI]) of 0.80 (0.66-0.91), P = .001, followed by the ROTEM A10 PC with AUC (95% CI) of 0.75 (0.51-0.99), P = .004, and PC with AUC (95% CI) of 0.74 (0.50-0.99), P = .009. The Multiplate ADPtest had an AUC (95% CI) of 0.67 (0.42-0.91), and the TRAPtest had an AUC (95% CI) of 0.62 (0.37-0.86). The cutoff values identified were 13 hPa for the QUANTRA PCS, 40 mm for the ROTEM A10, and 48.5 mm for the ROTEM PC, with negative predictive values of 84%, 81%, and 86%, respectively, and positive predictive values of 55%, 53%, and 69%, respectively.

CONCLUSIONS

QUANTRA PCS, ROTEM A10 PC, and Multiplate ADPtest showed a significant decrease after CPB, whereas ROTEM PC and Multiplate TRAPtest did not. Major bleeding was predicted with a moderate to good discrimination by the post-CPB viscoelastic tests (PCS, PC, and A10 PC).

Association of miR-144 levels in the peripheral blood with COVID-19 severity and mortality

Coronavirus disease-2019 (COVID-19) can be asymptomatic or lead to a wide symptom spectrum, including multi-organ damage and death. Here, we explored the potential of microRNAs in delineating patient condition and predicting clinical outcome. Plasma microRNA profiling of hospitalized COVID-19 patients showed that miR-144-3p was dynamically regulated in response to COVID-19. Thus, we further investigated the biomarker potential of miR-144-3p measured at admission in 179 COVID-19 patients and 29 healthy controls recruited in three centers. In hospitalized patients, circulating miR-144-3p levels discriminated between non-critical and critical illness (AUC_miR-144-3p = 0.71; p = 0.0006), acting also as mortality predictor (AUC_miR-144-3p = 0.67; p = 0.004). In non-hospitalized patients, plasma miR-144-3p levels discriminated mild from moderate disease (AUC_miR-144-3p = 0.67; p = 0.03). Uncontrolled release of pro-inflammatory cytokines can lead to clinical deterioration. Thus, we explored the added value of a miR-144/cytokine combined analysis in the assessment of hospitalized COVID-19 patients. A miR-144-3p/Epidermal Growth Factor (EGF) combined score discriminated between non-critical and critical hospitalized patients (AUC_{miR-144-3p/EGF} = 0.81; p < 0.0001); moreover, a miR-144-3p/Interleukin-10 (IL-10) score discriminated survivors from nonsurvivors (AUC_{miR-144-3p/IL-10} = 0.83; p < 0.0001). In conclusion, circulating miR-144-3p, possibly in combination with IL-10 or EGF, emerges as a noninvasive tool for early risk-based stratification and mortality prediction in COVID-19.

Microcirculatory Alterations in Critically Ill Patients with COVID-19-Associated Acute Respiratory Distress Syndrome

Background: Presently, a number of specific observations have been performed on microcirculatory function in a coronavirus disease-19 (COVID-19) setting. We hypothesized that, in the critically ill, endothelial dysfunction secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the subsequent inflammation and coagulopathy may lead to microcirculatory alterations, further exacerbated by the hypoxemic state. A dysfunctional microcirculation may represent the hidden motor underlying the development of COVID-19’s clinical manifestations. Methods: A single center, prospective, observational study. We analyzed bedside sublingual microcirculation in twenty-four consecutive COVID-19-associated acute respiratory distress syndrome (ARDS) patients mechanically ventilated in an Intensive Care Unit (ICU), together with macro-hemodynamics, clinical parameters, echocardiography, and laboratory data at a single time-point after ICU admission. All participants were recruited between March and May 2020. Results: The microcirculatory pattern was characterized by increased values of total vessel density and perfused vessel density, a reduced value of proportion of perfused vessels and microvascular flow index, and high values of heterogeneity index. The duration of mechanical ventilation before microcirculation assessment was inversely associated with the proportion of perfused vessels (p = 0.023). Within the macro-hemodynamic parameters, the right ventricle end-diastolic diameter was inversely associated with proportion of perfused vessels and microvascular flow index (p = 0.039 and 0.014, respectively) and directly associated with the heterogeneity index (p = 0.033). Conclusions: In COVID-19-associated ARDS patients, the microcirculation showed impaired quality of flow parameters coupled with a high vessel density.

A Comparative Study of Multiple Electrode Aggregometry Technologies in Cardiac Surgery: Different Values, Same Clinical Relevance

OBJECTIVES

The assessment of platelet function in cardiac surgery patients who recently received dual-antiplatelet therapy is considered in the existing guidelines. Among available devices, Multiplate (MP) and ROTEM Platelet (RP) are both based on electrical impedance. This study aimed to determine the agreement between MP and RP in cardiac surgery patients under dual-antiplatelet therapy discontinued before surgery. Secondarily, it compared the ability of the MP and RP in predicting postoperative bleeding and the need for platelet transfusion.

DESIGN

A prospective cohort study.

SETTING

A hospital in Milan, Italy.

PARTICIPANTS

Fifty adult patients preoperatively and postoperatively tested.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were studied with adenosine diphosphate (ADP) and thrombin receptor-activating peptide (TRAP) testing on both of the devices. The mean preoperative ADP tests were below the respective lower limit of the reference value, thus reflecting a good ability of these tests to detect the residual or ongoing effects of antiplatelet drugs acting on the P2Y₁₂ receptor. The agreement between the 2 methodologies was very poor for both the ADP and TRAP tests, with a percentage error of 80%. The preoperative ADP tests were predictive for the need of platelet concentrate transfusion, with cut-off values at 35 U for the ADP-MP and 60 Ω/min for the ADP-RP. No correlation was found for postoperative bleeding.

CONCLUSION

Both technologies seemed to offer potential benefits in the surgical approach to patients who preoperatively received antiplatelet drugs. However, the results of these tests are not interchangeable, and different cut-off values should be applied.

A European consensus statement on the use of four-factor prothrombin complex concentrate for cardiac and non-cardiac surgical patients

Modern four-factor prothrombin complex concentrate was designed originally for rapid targeted replacement of the coagulation factors II, VII, IX and X. Dosing strategies for the approved indication of vitamin K antagonist-related bleeding vary greatly. They include INR and bodyweight-related protocols as well as fixed dose regimens. Particularly in the massively bleeding trauma and cardiac surgery patient, four-factor prothrombin complex concentrate is used increasingly for haemostatic resuscitation. Members of the Transfusion and Haemostasis Subcommittee of the European Association of Cardiothoracic Anaesthesiology performed a systematic literature review on four-factor prothrombin complex concentrate. The available evidence has been summarised for dosing, efficacy, drug safety and monitoring strategies in different scenarios. Whereas there is evidence for the efficacy of four-factor prothrombin concentrate for a variety of bleeding scenarios, convincing safety data are clearly missing. In the massively bleeding patient with coagulopathy, our group recommends the administration of an initial bolus of 25 IU.kg^-1 . This applies for: the acute reversal of vitamin K antagonist therapy; haemostatic resuscitation, particularly in trauma; and the reversal of direct oral anticoagulants when no specific antidote is available. In patients with a high risk for thromboembolic complications, e.g. cardiac surgery, the administration of an initial half-dose bolus (12.5 IU.kg^-1 ) should be considered. A second bolus may be indicated if coagulopathy and microvascular bleeding persists and other reasons for bleeding are largely ruled out. Tissue-factor-activated, factor VII-dependent and heparin insensitive point-of-care tests may be used for peri-operative monitoring and guiding of prothrombin complex concentrate therapy.

The procoagulant pattern of patients with COVID-19 acute respiratory distress syndrome

BACKGROUND

Few observations exist with respect to the pro-coagulant profile of patients with COVID-19 acute respiratory distress syndrome (ARDS). Reports of thromboembolic complications are scarce but suggestive for a clinical relevance of the problem.

OBJECTIVES

Prospective observational study aimed to characterize the coagulation profile of COVID-19 ARDS patients with standard and viscoelastic coagulation tests and to evaluate their changes after establishment of an aggressive thromboprophylaxis.

METHODS

Sixteen patients with COVID-19 ARDS received a complete coagulation profile at the admission in the intensive care unit. Ten patients were followed in the subsequent 7 days, after increasing the dose of low molecular weight heparin, antithrombin levels correction, and clopidogrel in selected cases.

RESULTS

At baseline, the patients showed a pro-coagulant profile characterized by an increased clot strength (CS, median 55 hPa, 95% interquartile range 35-63), platelet contribution to CS (PCS, 43 hPa; interquartile range 24-45), fibrinogen contribution to CS (FCS, 12 hPa; interquartile range 6-13.5) elevated D-dimer levels (5.5 μg/mL, interquartile range 2.5-6.5), and hyperfibrinogenemia (794 mg/dL, interquartile range 583-933). Fibrinogen levels were associated (R2  = .506, P = .003) with interleukin-6 values. After increasing the thromboprophylaxis, there was a significant (P = .001) time-related decrease of fibrinogen levels, D-dimers (P = .017), CS (P = .013), PCS (P = .035), and FCS (P = .038).

CONCLUSION

The pro-coagulant pattern of these patients may justify the clinical reports of thromboembolic complications (pulmonary embolism) during the course of the disease. Further studies are needed to assess the best prophylaxis and treatment of this condition.

Monitoring the effectiveness of hypothermia in perinatal asphyxia infants by urinary S100B levels

Background Perinatal asphyxia is a major cause of mortality and morbidity in neonates: The aim of the present study was to investigate, by means of longitudinal assessment of urinary S100B, the effectiveness of hypothermia, in infants complicated by perinatal asphyxia and hypoxic-ischemic encephalopathy. Methods We performed a retrospective case-control study in 108 asphyxiated infants, admitted to nine tertiary departments for neonatal intensive care from January 2004 to July 2017, of whom 54 underwent hypothermia treatment and 54 did not. The concentrations of S100B protein in urine were measured using an immunoluminometric assay at first urination and 4, 8, 12, 16, 20, 24, 48, 72, 96, 108 and 120 h after birth. The results were correlated with the achievement of S100B levels within normal ranges at 72 h from hypothermia treatment. Routine laboratory parameters, longitudinal cerebral function monitoring, cerebral ultrasound and neurologic patterns were assessed according to standard protocols. Results Higher S100B concentrations were found in hypothermia-treated infants in both moderate (up to 12 h) and severe (up to 24 h) hypoxic-ischemic encephalopathy. S100B levels returned to normal ranges starting from 20 h of hypothermia treatment in moderate and from 36 h in severe hypoxic-ischemic encephalopathy. Conclusions The present results offer additional support to the usefulness of longitudinal neuro-biomarkers monitoring in asphyxiated infants treated by hypothermia. The pattern of S100B concentrations during hypothermia supports the need for further investigations aimed at reconsidering the time-window for patient recruitment and treatment, and the optimal duration of the cooling and rewarming phases of the hypothermia procedure.

Sensitivity of Viscoelastic Tests to Platelet Function

Viscoelastic tests provide a dynamic assessment of coagulation, by exploring the time to clot formation and the clot strength. Using specific activators or inhibitors, additional factors can be explored, like the fibrinogen contribution to clot strength. Since the early days, various attempts have been done to measure platelet function with viscoelastic test. In general, the difference between the maximum clot strength and the fibrinogen contribution is considered an index of platelet contribution. However, this parameter does not clearly split platelet count from function; additionally, the extensive thrombin generation of standard activated viscoelastic tests activates platelet through the protease activated receptors, bypassing the other pathways. For this reason, standard viscoelastic tests cannot be used to assess platelet reactivity under the effects of aspirin or P2Y12 inhibitors. To overcome this limitation, a specific test was developed (thromboelastography platelet mapping). This test has been compared with the gold standard of light transmission aggregometry and with other point-of-care tests, with conflicting results. In general, the use of viscoelastic tests to assess the effects of antiplatelet agents is still limited. Conversely, platelet contribution to clot strength in the setting of coagulopathic bleeding is considered an important parameter to trigger platelet transfusion or desmopressin.

Antenatal maternal antidepressants drugs treatment affects S100B levels in maternal-fetal biological fluids in a dose dependent manner

BACKGROUND

The increased use of antidepressant treatment during pregnancy occurred without firm evidence on safety/efficacy. The present study investigated the correlation among S100B and paroxetine blood levels with the occurrence of short-term post-natal neurological abnormalities.

METHODS

We conducted a cross-sectional study in 50 pregnant women using paroxetine because of depression and in 150 controls. Standard laboratory parameters and S100B were measured at seven monitoring time-points (maternal blood: T1, 16-20 wks; T2, 27-30 wks; T3, 35-40 wks; T4, at delivery; amniotic fluid, T5; venous and arterial cord blood, T6-T7). Paroxetine levels were measured at T1-T6. Neurological outcome was set at 7th day from birth.

RESULTS

Higher S100B concentrations at T1-T7 were found in the paroxetine-treated group. S100B correlated with paroxetine blood levels. The paroxetine/S100B ratio cut-off of 1.31 at T2 achieved sensitivity 100%, specificity 96.5% and positive/negative predictive values 87.5-100, respectively, as a single marker to predict adverse neonatal neurological outcome.

CONCLUSIONS

The present study offers additional support to the usefulness of longitudinal S100B and drug level monitoring in depressed pregnant women and in the early detection of cases at risk for short-term neurological abnormalities. Results open the way at further investigations correlating antidepressant drugs and neurobiomarkers in the maternal bloodstream.

Anti-Factor Xa-Based Anticoagulation during Extracorporeal Membrane Oxygenation: Potential Problems and Possible Solutions

Choices for monitoring of unfractionated heparin (UFH) anticoagulation in extracorporeal membrane oxygenation (ECMO) patients include activated clotting time, activated partial thromboplastin time, reaction times of viscoelastic tests, and anti-factor Xa activity (between 0.3 and 0.7 IU/mL). Recent studies propose the anti-factor Xa to be the gold standard for monitoring UFH anticoagulation in ECMO. However, many extraneous factors combined question the utility of anti-factor Xa as the sole method of monitoring of UFH effects in ECMO. Anti-factor Xa is a chromogenic assay, which may be biased by the frequently elevated values of bilirubin and free hemoglobin in ECMO patients. The test may alternatively underestimate UFH effects in cases of low antithrombin values. More importantly, the anti-factor Xa assay is a plasma-based test which does not take into account the role of platelets and fibrinogen in forming a stable clot. Thrombocytopenia and platelet dysfunction are common features in ECMO patients, and underestimating their role may lead to over-anticoagulation, should only anti-factor Xa guiding be used to adjust the UFH dose. Conversely, fibrinogen is an acute phase protein, and some patients may experience high levels of fibrinogen during the ECMO course. In this case, an UFH monitoring based on anti-factor Xa is insensitive to this condition, although it may potentially be associated with thrombotic complications. Finally, the generally suggested range of 0.3 to 0.7 IU/mL is a somewhat arbitrary estimate, based on the desired range for treating and preventing thrombotic events in non-ECMO patients. In conclusion, anti-factor Xa may offer useful information on the real effects of UFH only when combined with a whole blood test capable of assessing the relative contribution of platelets and fibrinogen to clot formation.

Glutathione Blood Concentrations: A Biomarker of Oxidative Damage Protection during Cardiopulmonary Bypass in Children

Background. Pediatric open-heart surgery with cardiopulmonary bypass (CPB) still remains a risky interventional procedure at high mortality/morbidity. To date, there are no clinical, laboratory, and/or monitoring parameters providing useful information on perioperative stress. We therefore investigated whether blood concentrations of glutathione (GSH), a powerful endogenous antioxidant, changed in the perioperative period. Methods. We conducted an observational study in 35 congenital heart disease (CHD) children in whom perioperative standard laboratory and monitoring parameters and GSH blood levels were assessed at five monitoring time points. Results. GSH showed a pattern characterized by a progressive increase from pre-surgery up to 24 h after surgery, reaching its highest peak at the end of CPB. GSH measured at the end of CPB correlated with CPB duration, cross-clamping, arterial oxygen partial pressure, and with body core temperature. Conclusions. The increase in GSH levels in the perioperative period suggests a compensatory mechanism to oxidative damage during surgical procedure. Caution is needed in controlling different CPB phases, especially systemic reoxygenation in a population that is per se more prone to oxidative stress/damage. The findings may point the way to detecting the optimal temperature and oxygenation target by biomarker monitoring.

Fibrinogen levels and postoperative chest drain blood loss in low-weight (<10 kg) children undergoing cardiac surgery

Introduction:

Low-weight (<10 kg) children undergoing cardiac surgery with cardiopulmonary bypass are prone to dilution and consumption of soluble coagulation factors and fibrinogen. Low levels of fibrinogen may represent a possible cause of severe postoperative chest drain blood loss. The present study investigates the association between post–cardiopulmonary bypass fibrinogen levels and postoperative chest drain blood loss and severe bleeding, aiming to identify possible cut-off values to trigger specific interventions.

Methods:

Prospective cohort study on 77 patients weighing <10 kg undergoing cardiac surgery with cardiopulmonary bypass. Haemostasis and coagulation data were collected before surgery (standard tests and thromboelastometry), after protamine (thromboelastometry) and at the arrival in the intensive care unit (standard tests). The primary outcome variable was severe bleeding (chest drain blood loss >30 ml kg-1/24h).

Results:

Factors being independently associated with severe bleeding were the international normalized ratio and the fibrinogen levels at the arrival in the intensive care unit. Once corrected for other confounders, fibrinogen levels had an odds ratio of 0.2 (95% confidence interval = 0.011-0.54) per 1 gL-1for severe bleeding. The discrimination power was fair (area under the curve = 0.770). The best cut-off value was identified at a fibrinogen level of 150 mg dL-1, with a sensitivity of 52%, a specificity of 85% and a positive predictive value of 60% for severe bleeding.

Conclusion:

Both a prolonged international normalized ratio and low fibrinogen levels were predictive for severe bleeding, underscoring the role of coagulation factors dilution and consumption in this specific patient population.

Inflammation and coagulation following minimally invasive extracorporeal circulation technologies

Minimally invasive extracorporeal perfusion technologies are based on the use of a minimally invasive extracorporeal circulation (MiECC) system. This includes a closed CPB circuit; biologically inert blood contact surfaces; reduced priming volume; a centrifugal pump; a membrane oxygenator; a heat exchanger; a cardioplegia system; a venous bubble trap/venous air removing device; and a shed blood management system. Some of these items, alone or in combination, are able to modify the blood activation usually elicited by cardiopulmonary bypass (CPB). The hemostatic system activation is less activated and lower degrees of thrombin generation and platelet activation have been found in numerous studies. Additionally, the reduced level of hemodilution plays an important role in preserving clot firmness after CPB with MiECC. These biochemical changes are reflected by a blood loss containment, a reduced need for allogeneic blood transfusions, and, in some studies, by a lower thromboembolic complications rate. The activation of the inflammatory cascade is in turn limited by MiECC, both directly (through a blunting of the contact-phase activation) and indirectly (through a limited thrombin generation, platelet activation, and consequent lower release of pro-inflammatory cytokines). The clinical consequences of this are mainly demonstrated by a lower rate of postoperative atrial fibrillation; other inflammation-derived outcomes appear favorably affected by MiECC (lung function, acute kidney injury) but the multi-factorial nature of these complications makes difficult to clearly attribute this pattern to a lower degree of inflammation. Overall, the existing body of evidence is in favor of MiECC with respect to standard CPB.

The combined effects of the microcirculatory status and cardiopulmonary bypass on platelet count and function during cardiac surgery

BACKGROUND

Cardiac surgery with cardiopulmonary bypass is associated with important changes in the microcirculation, usually attributed to endothelial dysfunction. Another common finding of cardiac surgery is postoperative thrombocytopenia and platelet loss of function.

OBJECTIVE

To investigate the association between microvascular flow pattern and postoperative changes in platelet count and function in cardiac surgery patients.

METHODS

Twelve adult cardiac surgery patients received microvascular circulation (sidestream darkfield sublingual mucosa analysis) and platelet count and function (multiple electrode aggregometry ADPtest and TRAPtest) assessment before and after cardiopulmonary bypass.

RESULTS

After cardiopulmonary bypass, sublingual microcirculation showed a significantly (P = 0.001) decreased microvascular flow index and increased heterogeneity index (P = 0.006). Platelet function significantly decrease after cardiopulmonary bypass both at ADPtest (P = 0.011) and TRAPtest (P = 0.002). Preoperative patterns of poor microvascular perfusion (low perfused vessels density and total vessels density) were significantly associated with lower values of post-cardiopulmonary bypass platelet function (ADPtest, P = 0.009, TRAPtest, P = 0.031) and count (P = 0.048).

CONCLUSIONS

A preoperative disturbance of the microcirculation is associated with a greater postoperative platelet dysfunction. Endothelial damage, chemical and mechanical stimuli are the possible link between the two patterns.

Platelet function after cardiac surgery and its association with severe postoperative bleeding: the PLATFORM study

Platelet dysfunction after cardiac surgery is a determinant of postoperative bleeding. The existing guidelines suggest the use of desmopressin and/or platelet concentrate transfusions in case of platelet dysfunction in bleeding patients, but no cut-off values for platelet activity exist in the literature. The Platelet Function in the Operating Room (PLATFORM) study aims to identify the relationship between platelet function after cardiopulmonary bypass and severe bleeding, finding adequate predictive values of platelet function for severe bleeding. The PLATFORM is a prospective cohort study on 490 adult patients receiving cardiac surgery with cardiopulmonary bypass. Patients received platelet function tests (multiple electrode aggregometry ADPtest and TRAPtest) before surgery and after cardiopulmonary bypass, and routine coagulation tests before surgery and at the arrival in the intensive care unit. The post-cardiopulmonary bypass ADPtest and TRAPtest were significantly (P = 0.001) associated with severe bleeding, as well as the post-cardiopulmonary bypass activated partial thromboplastin time, the international normalized ratio, and the fibrinogen concentration. At a multivariable analysis, the ADPtest (odds ratio 0.962, 95% confidence interval 0.936-0.989, P = 0.005) and the activated partial thromboplastin time (odds ratio 1.097, 95% confidence interval 1.016-1.185, P = 0.017) remained independently associated with severe bleeding. The post-cardiopulmonary bypass ADPtest had the best discrimination, with an area under the curve of 0.712. The best positive predictive value (42%) was found at a cut-off ≤8 U. In conclusion, platelet function tests after cardiopulmonary bypass are significantly associated with postoperative bleeding. However, postoperative bleeding has a multifactorial nature, and the measure of platelet function alone does not provide a high positive predictive value for severe bleeding.

Microcirculatory changes in children undergoing cardiac surgery: a prospective observational study

BACKGROUND

The effects of cardiac surgery on the microcirculation of children are unknown. The aim of this study was to assess the microcirculatory changes in children undergoing surgery for correction of congenital heart disease.

METHODS

We used a videomicroscope (Sidestream Dark Field, SDF) in a convenience sample of 24 children <five yr old. Total vascular density (TVD, vessels mm(-2)), microvascular flow index (MFI, arbitrary units), proportion of perfused small vessels (PPV, percentage), and perfused vessel density (PVD) were obtained after induction of anaesthesia (T1), at the end of the surgical procedure (T2), after intensive care unit (ICU) admission (T3), and at six h (T4) and 12h (T5) after ICU admission.

RESULTS

Microcirculatory variables did not significantly change over time. Haemodynamic parameters and microcirculatory variables were not correlated. In a subanalysis conducted for cyanotic (n=7) and acyanotic (n=17) children, repeated measures ANOVA showed a significant interaction between time and the presence of cyanosis for PPV (P=0.03), TVD (P=0.03), and PVD (P=0.03). Weak inverse correlations were found between storage time of transfused red blood cell (RBCs) and MFI at T3 (r=-0.63, P=0.01) and T4 (r=-0.53, P=0.03).

CONCLUSIONS

Microcirculatory variables have a different time-related trend in cyanotic and acyanotic children undergoing cardiac surgery. The storage time of transfused RBCs seems to negatively impact the microcirculation. Further and larger studies are warranted to prove the potential implications of this study.

Platelet reactivity in overweight and obese patients undergoing cardiac surgery

Body mass index (BMI) and specifically overweight and obesity have been associated with an increased platelet reactivity in different series of patients. This information is derived by different laboratory platelet function tests (PFTs) like mean platelet volume (MPV), platelet microparticles, thromboxane B2 metabolites, and others. Point-of-care PFT, which are often used in cardiac surgery, are rarely addressed. The present study aims to verify platelet reactivity using multiple-electrode aggregometry (MEA) as a function of BMI in cardiac surgery patients. One-hundred ninety-eight cardiac surgery patients free from the effects of drugs acting on the P2Y₁₂ receptor and undergoing cardiac surgery received MEA-PFT immediately before surgery. Platelet reactivity was compared between normal weight and overweight-obese subjects. There were 99 underweight/normal (BMI < 25), 60 overweight (BMI ≥ 25) and 39 obese (BMI ≥ 30) patients. Overweight-obese patients did not show higher platelet counts nor a clear platelet hyper-reactivity, when tested with MPV and MEA ADP test. At TRAPtest, the overweight/obese patients had a significantly (P = 0.011) higher platelet reactivity (median 118, interquartile range 106-136) than controls (median 112, interquartile range 101-123) and a higher rate of platelet hyper-reactivity (odds ratio 2.19, 95% confidence interval 1.15-4.16, P = 0.016) in a multivariable model. A minor association was found between the BMI and platelet reactivity at TRAPtest, with a higher degree of activity for increasing BMI. The BMI determines an increased thrombin-dependent platelet reactivity in cardiac surgery patients. Thrombin is extensively formed during cardiac surgery, and this may explain the lower postoperative bleeding observed in obese patients in previous studies.

Fibrinogen measurement in cardiac surgery with cardiopulmonary bypass: Analysis of repeatability and agreement of Clauss method within and between six different laboratories

Plasma fibrinogen concentration is important for coagulopathy assessment, and is most commonly measured using the Clauss method. Several factors, including device type and reagent, have been shown to affect results. The study objective was to evaluate performance and repeatability of the Clauss method and to assess differences between measurements performed during and after cardiopulmonary bypass (CPB), by testing plasma samples from patients undergoing cardiac surgery with CPB. Samples were collected from 30 patients before surgery, approximately 20 minutes before weaning from CPB, and 5 minutes after CPB and protamine. Fibrinogen concentration was determined using the Clauss method at six quality-controlled specialised laboratories, according to accredited standard operating procedures. Regarding within-centre agreement for Clauss measurement, mean differences between duplicate measurements were between 0.00 g/l and 0.15 g/l, with intervals for 95% limits of agreement for mean Bland-Altman differences up to 1.3 g/l. Regarding between-centre agreement, some mean differences between pairs of centres were above 0.5 g/l. Differences of up to ∼2 g/l were observed with individual samples. Increased variability was observed between centres, with inter-class correlation values below 0.5 suggesting only fair agreement. There were no significant differences in fibrinogen concentration before weaning from CPB and after CPB for most centres and methods. In conclusion, considerable differences exist between Clauss-based plasma fibrinogen measured using different detection methods. Nevertheless, the similarity between measurements shortly before weaning from CPB and after CPB within centres suggests that on-pump measurements could provide an early estimation of fibrinogen deficit after CPB and thus guidance for haemostatic therapy.

S100B increases in cyanotic versus noncyanotic infants undergoing heart surgery and cardiopulmonary bypass (CPB)

AIMS

S100B has been proposed as a consolidated marker of brain damage in infants with congenital heart disease (CHD) undergoing cardiac surgery and cardiopulmonary bypass (CPB). The present study aimed to investigate whether S100B blood levels in the perioperative period differed in infants complicated or not by cyanotic CHD (CHDc) and correlated with oxygenation status (PaO₂).

METHODS

We conducted a case-control study of 48 CHD infants without pre-existing neurological disorders undergoing surgical repair and CPB. 24 infants were CHDc and 24 were CHD controls. Blood samples for S100B assessment were collected at six monitoring time-points: before the surgical procedure (T0), after sternotomy but before CPB (T1), at the end of the cross-clamp CPB phase (T2), at the end of CPB (T3), at the end of the surgical procedure (T4), at 24 h postsurgery (T5).

RESULTS

In the CHDc group, S100B multiples of median (MoM) were significantly higher (p < .05, for all) from T0 to T5. PaO₂ was significantly lower (p < .05, for all) in CHDc infants at T0-T1 and at T4 while no differences (p > .05, for all) were found at T2, T3, T5. Linear regression analysis showed a positive correlation between S100B MoM at T3 and PaO₂ (R = 0.84; p < .001).

CONCLUSIONS

The present data showing higher hypoxia/hyperoxia-mediated S100B concentrations in CHDc infants suggest that CHDc are more prone to perioperative brain stress/damage and suggest the usefulness of further investigations to detect the "optimal" PaO₂ target in order to avoid the side effects associated with reoxygenation during CPB.

S100B maternal blood levels are gestational age- and gender-dependent in healthy pregnancies

BACKGROUND

S100B is a well-established biomarker of central nervous system (CNS) development and damage in the perinatal period. Because the fetal CNS induces an overproduction of S100B measurable in the maternal bloodstream we evaluated S100B protein in healthy pregnancies in order to provide a reference curve of the protein in the second and third trimesters and to provide information on CNS development when standard monitoring procedures could be silent or unavailable.

METHODS

Between July 2012 and December 2014 we conducted a prospective study in 1213 healthy pregnancies delivering healthy newborns. Maternal blood samples were collected for standard monitoring procedures and S100B assessment. S100B correlations with selected outcomes (gestational age at sampling, gender of fetus, gestational age and weight at birth, delivery mode) were calculated using multiple forward stepwise regression analysis.

RESULTS

S100B concentrations in the second and third trimesters of pregnancy were found to be gestational age-, gender- and delivery mode-dependent (p<0.05, for all). Multiple forward stepwise regression analysis with S100B as the dependent variable and gestational age at sampling, gender, delivery mode, gestational age and weight at birth as independent variables, showed a significant correlation between S100B and gestational age at sampling (R=0.13; p<0.001).

CONCLUSIONS

The present findings offering a S100B protein reference curve in maternal blood suggest that non-invasive fetal CNS monitoring is becoming feasible and open the way to further research in neuro-biomarker assessment in the maternal bloodstream.

Fibrinogen levels compensation of thrombocytopenia-induced bleeding following cardiac surgery

BACKGROUND

After cardiopulmonary bypass (CPB) thrombocytopenia is a relatively common pattern which may trigger postoperative bleeding. The purpose of this study is to verify if the endogenous fibrinogen levels are independent determinants of chest drain blood loss and need for allogeneic blood products transfusions in a clinical model of post-CPB thrombocytopenia.

METHODS

Retrospective analysis on 445 consecutive patients having a platelet count <100×1000cells/μL after CPB. Based on the fibrinogen levels the patients were divided into three groups with similar platelet count and low (LF, median 170mg/dL), intermediate (IF, median 215mg/dL), and high (HF, median 280mg/dL), fibrinogen levels. Chest drain blood loss (mL/12h), transfusion rate of red blood cells (RBC), fresh frozen plasma (FFP) and platelet concentrates were assessed and compared between groups.

RESULTS

There was a significant (P=0.001) difference in chest drain blood loss with higher values in the LF group (487mL/12h, IQR 300-600mL/12h) than in the IF group (350mL/12h, IQR 200-500mL/12h) and the HF group (300mL/12h, IQR 200-475mL/12h). Transfusion rates of FFP significantly (P=0.014) differed between groups (LF: 18.4%, IF: 7.9%, HF: 9.2%) and platelet concentrate transfusions significantly (P=0.020) differed between groups (LF: 23.5%, IF: 16.5%, HF: 10.7%). In multivariable models, these differences were confirmed. Thromboelastography parameters showed an effective compensation of clot firmness in group HF vs. IF and LF.

CONCLUSIONS

Levels of fibrinogen >240mg/dL compensate the decrease in clot firmness observed in thrombocytopenic patients following CPB, and reduce bleeding and transfusion needs.

The effectiveness of 10 years of interventions to control postoperative bleeding in adult cardiac surgery

Objectives

Postoperative bleeding in cardiac surgery remains an important complication, leading to increased morbidity and mortality. Different interventions are possible to prevent/treat postoperative bleeding. The present study aims to investigate the effectiveness of these interventions in a real-world scenario.

Methods

This is a retrospective study based on 19 670 consecutive adult cardiac surgery patients operated from 2000 to 2015. During the study period, the following interventions have been applied and tested for effectiveness with a before versus after analysis: thromboelastography (TEG)-based diagnosis and treatment in actively bleeding patients; platelet function tests (PFTs); timing of surgery based on PFTs; fresh frozen plasma (FFP)-free strategy using prothrombin complex concentrate and fibrinogen concentrate.

Results

TEG-based diagnostic and therapeutic approach resulted in a significant (P = 0.006) reduction of postoperative bleeding and significant (P = 0.001) increase in platelet concentrate transfusion rate. Timing of surgery based on PFTs resulted in a significant reduction of postoperative bleeding (P = 0.001), surgical re-exploration rate (P = 0.002), FFP (P = 0.001) and platelet concentrate (P = 0.016) transfusion rate. FFP-free strategy was associated with a significant decrease in postoperative bleeding (P = 0.005) and FFP transfusions (P = 0.001). The combination of all the interventions was associated with a significant (P = 0.001) reduction in postoperative bleeding, surgical re-exploration rate and FFP transfusions, whereas platelet concentrate transfusion rate was significantly (P = 0.001) higher.

Conclusions

Despite a continuous increase in the bleeding risk profile, the application of a bundle of interventions is effective in controlling postoperative bleeding and related complications. Platelet transfusions remain unreplaceable in the present scenario.

Point-of-Care Coagulation Tests Monitoring of Direct Oral Anticoagulants and Their Reversal Therapy: State of the Art

Direct oral anticoagulants (DOACs) exert similar anticoagulant effects to vitamin K antagonists and are increasingly used worldwide. Nevertheless, an evidence-based approach to patients receiving DOACs when any unplanned urgent surgery or bleeding (either spontaneous or traumatic) occurs is still missing. In this review, we investigate the role of point-of-care coagulation tests when other, more specific tests are not available. Indeed, thromboelastography and activated clotting time can detect dabigatran-induced coagulopathy, while their accuracy is limited for apixaban and rivaroxaban, mostly in cases of low drug plasma concentrations. These tests can also be used to guide the reversal of DOAC-induced coagulopathy providing a quick, before-and-after picture in case of therapeutic use of hemostatic compounds.

Desmopressin after cardiac surgery in bleeding patients. A multicenter randomized trial

BACKGROUND

Previous studies showed that desmopressin decreases post-operative blood loss in patients undergoing cardiac surgery. These studies were small and never studied the effect of desmopressin in patients with active bleeding. Objective of the study was to determine whether desmopressin reduces red blood cells transfusion requirements in patients with active bleeding after cardiac surgery who had been pre-treated with tranexamic acid.

METHODS

This multicenter, randomized, double-blind, placebo-controlled, parallel-group study randomized elective patients with bleeding after cardiac surgery despite pre-treatment with tranexamic acid, to receive placebo (saline solution) or a single administration of desmopressin (0.3 μg/kg in saline solution). The primary endpoint was the number of patients requiring red blood cells transfusion after randomization and during hospital stay. Secondary end points were: blood loss from chest tubes during the first 24 h after study drug administration, hours of mechanical ventilation, intensive care unit stay, and in-hospital mortality.

RESULTS

The study was interrupted after inclusion of 67% of the planned patients for futility. The number of patients requiring red blood cells transfusion after randomization was 37/68 (54%) in desmopressin group and 33/67 (49%) in placebo group (P = 0.34) with no difference in blood loss: 575 (interquartile 422-770) ml in desmopressin group and 590 (476-1013) ml in placebo group (P = 0.42), mechanical ventilation, intensive care unit stay or mortality.

CONCLUSIONS

This multicenter randomized trial demonstrated that, in patients pre-treated with tranexamic acid, desmopressin should not be expected to improve treatment of patients who experience bleeding after cardiac surgery.

Coagulation monitoring in postcardiotomy ECMO: conventional tests, point-of-care, or both?

BACKGROUND

The aim of this study was to assess the association of the coagulation point-of-care (POC) tests activated clotting time (ACT) and thromboelastography-derived parameters reaction time (R-time) and maximum amplitude (MA) with the standard coagulation tests during postcardiotomy extracorporeal membrane oxygenation (ECMO), finding adequate values predictive for the target range of the standard coagulation tests.

METHODS

Thirty-one patients undergoing postcardiotomy ECMO with heparin anticoagulation were analyzed. Paired data of the POC tests and standard coagulation tests were analyzed for association and positive predictive value (PPV).

RESULTS

The following target range values for standard coagulation test were settled: activated partial thromboplastin time (aPTT) 50-70 seconds; international normalized ratio (INR) 1.5-2.5; platelet count >50,000 cells/µL; fibrinogen >150 mg/dL. The best predictor for the desired aPTT range was an ACT of 162-185 seconds. A combination of an ACT<162 seconds with an R-time <10 minutes had an 83% PPV for a short aPTT. A combination of an ACT>185 seconds with an R-time >27 minutes had a 71% PPV for a long aPTT. No predictive ability of the POC tests was found in terms of the optimal INR range. An MA value <41 mm had a 75% PPV for a low platelet count or fibrinogen level.

CONCLUSIONS

Diagnostic-therapeutic algorithms based on coagulation POC-tests may be useful to manage anticoagulation during postcardiotomy ECMO. The best PPV for prompting therapeutic decision is provided by a combination of ACT and visco-elastic tests.

Point-of-care haemostasis and coagulation monitoring in cardiac surgery at IRCCS Policlinico San Donato

A rational management of perioperative and postoperative bleeding in modern cardiac surgery requires a thorough application of point-of-care (POC) monitoring in order to prevent and readily treat alterations of the haemostatic process. Preoperative platelet dysfunction, residual heparin after extracorporeal circulation, coagulation factors, and/or fibrinogen deficiency could be ruled out and specifically addressed with an appropriate treatment. Our approach includes preoperative platelet function testing of patients administered with thienopyridines or ticagrelor within 7-10 days before planned surgery and platelet function testing-based surgery timing. In the case of postoperative bleeding, residual heparin is tested and additional protamine is eventually administered. Simultaneously, an overall activity of coagulation factors (except fibrinogen) is assessed and, if significantly reduced, correction with prothrombotic complex concentrate is considered. If fibrinogen deficiency is suspected, a specific test is run, and in the case of severe reduction, the deficiency is compensated by fibrinogen concentrate or appropriate volume of fresh-frozen plasma. If both coagulation factors and fibrinogen activity are reduced, fibrinogen is usually considered for correction as first line, followed by prothrombin complex concentrate in the case of further bleeding. It is our clinical practice not to test nor to treat patients until postoperative bleeding appears clinically relevant. At IRCCS Policlinico San Donato, we firmly believe in the importance of the POC-based strategy for haemostatic treatment and constantly update our knowledge through research projects targeted in answering clinically relevant questions.

Moderate-degree acidosis is an independent determinant of postoperative bleeding in cardiac surgery

BACKGROUND

Acidosis is a well-known factor leading to coagulopathy. It has been widely explored as a risk factor for severe bleeding in trauma patients. However, no information with respect to acidosis as a determinant of postoperative bleeding in cardiac surgery patients exists. The aim of this study was to investigate the role of acidosis and hyperlactatemia (HL) in determining postoperative bleeding and need for surgical revision in cardiac surgery patients.

METHODS

We carried out a retrospective analysis on 4521 patients receiving cardiac operations in two institutions. For each patient the preoperative data and operative profile was available. Arterial blood gas analysis data at the arrival in the intensive care unit were analyzed to investigate the association between acidosis (pH<7.35), HL (>4.0 mMol/L) and postoperative bleeding and surgical revision rate.

RESULTS

After correction for the potential confounders, both acidosis (P=0.001) and HL (P=0.001) were significantly associated with the amount of postoperative bleeding. HL was an independent risk factor for postoperative bleeding even in absence of acidosis. Overall, surgical revision rate was 5.6% in patients with HL and no acidosis; 7.7% in patients with acidosis and HL, and 7.2% in patients with acidosis and no HL. All these values are significantly (P=0.001) higher than the ones in patients without acidosis/HL (2%).

CONCLUSIONS

Even a moderate degree of postoperative acidosis is associated with a greater postoperative bleeding and surgical revision rate in cardiac surgery patients. Correction of acidosis with bicarbonate does not lead to an improvement of the postoperative bleeding asset.

Randomized, double-blinded, placebo-controlled trial of fibrinogen concentrate supplementation after complex cardiac surgery

BACKGROUND

Postoperative bleeding after heart operations is still a common finding, leading to allogeneic blood products transfusion. Fibrinogen and coagulation factors deficiency are possible determinants of bleeding. The experimental hypothesis of this study is that a first-line fibrinogen supplementation avoids the need for fresh frozen plasma (FFP) and reduces the need for any kind of transfusions.

METHODS AND RESULTS

This was a single-center, prospective, randomized, placebo-controlled, double-blinded study. One-hundred sixteen patients undergoing heart surgery with an expected cardiopulmonary bypass duration >90 minutes were admitted to the study. Patients in the treatment arm received fibrinogen concentrate after protamine administration; patients in the control arm received saline solution. In case of ongoing bleeding, patients in the treatment arm could receive prothrombin complex concentrates (PCCs) and those in the control arm saline solution. The primary endpoint was avoidance of any allogeneic blood product. Patients in the treatment arm had a significantly lower rate of any allogeneic blood products transfusion (odds ratio, 0.40; 95% confidence interval, 0.19 to 0.84, P=0.015). The total amount of packed red cells and FFP units transfused was significantly lower in the treatment arm. Postoperative bleeding was significantly (P=0.042) less in the treatment arm (median, 300 mL; interquartile range, 200 to 400 mL) than in the control arm (median, 355 mL; interquartile range, 250 to 600 mL).

CONCLUSIONS

Fibrinogen concentrate limits postoperative bleeding after complex heart surgery, leading to a significant reduction in allogeneic blood products transfusions. No safety issues were raised.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01471730.

Heparin-like effect in postcardiotomy extracorporeal membrane oxygenation patients

Introduction

Unfractionated heparin (UFH) is the anticoagulant of choice for extracorporeal membrane oxygenation (ECMO), but bivalirudin can be used as an alternative. The purpose of the present study is to investigate the existence of a heparin-like effect (HLE) during heparin-free ECMO.

Methods

This is a retrospective study on patients treated with ECMO and receiving bivalirudin as the sole anticoagulant. Thromboelastography (TEG) tests with and without heparinase were recorded during the ECMO duration. A total of 41 patients (22 pediatrics and 19 adults) treated with ECMO after cardiac surgery procedures and receiving only bivalirudin-based anticoagulation were studied. Based on the presence of a different reaction time (R-time) between the TEG test with heparinase or without heparinase we defined the presence of a HLE. Survival to hospital discharge, liver failure, sepsis, bleeding and transfusion rate were analyzed for association with HLE with univariate tests.

Results

HLE was detected in 56.1% of the patients. R-times were significantly shorter in tests done with heparinase versus without heparinase during the first seven days on ECMO. Patients with HLE had a significantly (P = 0.046) higher rate of sepsis (30%) than patients without HLE (5.6%) at a Pearson’s chi-square test.

Conclusions

A heparin-like effect is common during ECMO, and most likely due to a release of heparinoids from the glycocalyx and the mast cells, as a consequence of sepsis or of the systemic inflammatory reaction triggered by the contact of blood with foreign surfaces.

Plasma viscosity, functional fibrinogen, and platelet reactivity in vascular surgery patients

BACKGROUND

Platelet reactivity changes with shear stress, which in turn depends on whole blood and plasma viscosity (PV). Platelets interact with fibrinogen during thrombus formation, and fibrinogen is a determinant of PV. The respective role of PV and fibrinogen on platelet function is still unclear.

METHODS

30 patients undergoing vascular surgery were admitted to this study. In each patient we measured PV using a cone-on-plate viscosimeter, functional fibrinogen using thromboelastometry, and platelet reactivity to thrombin receptor activating peptide (TRAP) stimulation using multi-electrode aggregometry. Routine coagulation parameter were measured.

RESULTS

At the univariate analysis, platelet reactivity was positively associated with mean platelet volume (R2 = 0.15, P = 0.033) and PV (R2 = 0.35, P = 0.0006), and negatively associated with serum bilirubin (R2 = 0.20, P = 0.013) and international normalized ratio (INR) (R2 = 0.19, P = 0.017). At the multivariable analysis, only PV (P = 0.001) and INR (P = 0.019) remained independent predictors of platelet reactivity.

CONCLUSION

PV is directly and independently associated with platelet reactivity, whereas functional fibrinogen is not. Aspirin treatment is inadequate to correct thrombin-induced platelet aggregation. In presence of hyperviscosity, patients at high cardiovascular risk, may benefit from more aggressive anti-platelet treatments.