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.

Retuning mortality risk prediction in paediatric cardiac surgery: the additional role of early postoperative metabolic and respiratory profile.

OBJECTIVES: The existing risk stratification scores for paediatric patients undergoing cardiac surgery include the Aristotle Basic Complexity (ABC) Score, the Risk Adjustment in Congenital Heart Surgery-1 (RACHS-1) Score and the Aristotle Comprehensive Complexity (ACC) Score. They are all based on the nature of the surgical operation (ABC and RACHS-1 Scores) with possible adjustment for a number of patient conditions (ACC Score). The present study investigates if the early postoperative parameters may be used to improve the preoperative mortality risk prediction. METHODS: A retrospective study on 1392 consecutive patients aged ≤12 years old, undergoing cardiac surgery with cardiopulmonary bypass and without a residual right-to-left shunt was conducted. The ABC Score and metabolic and respiratory postoperative parameters at arrival in the intensive care unit were tested for association and discriminative power for operative mortality. RESULTS: The ABC yielded a c-statistic of 0.746. Additional independent predictors of operative mortality were postoperative hypoxia [Formula: see text] and arterial blood lactates. In a multivariable model including the ABC Score, postoperative hypoxia and arterial blood lactates remained independently associated with operative mortality. A modified ABC Score was created, consisting of the ABC Score plus 1.5 points in case of postoperative hypoxia plus 1 point per each 1 mmol/l of arterial blood lactates. The new model was significantly (P = 0.043) more discriminative than the ABC Score, with a c-statistic of 0.803. CONCLUSIONS: Early postoperative respiratory and metabolic parameters increased the accuracy and discrimination of the ABC Score. An external validation is needed to confirm our results.

Rhinocerebral zygomycosis: an unusual dramatic presentation in a paediatric cardiac patient without risk factors.

Mucormycosis is an angioinvasive infection caused by ubiquitous filamentous fungi of the order Mucorales. We describe a case of rhinocerebral mucormycosis presented in a paediatric patient after cardiac surgery correction of a complete atrioventricular canal defect. The rhinocerebral form of mucormycosis in our patient presented as an important epistaxis that needed immediate intubation due to blood inhalation. Furthermore, due to the worsening of pulmonary function, the patient also needed mechanical support with veno-arterial extracorporeal membrane oxygenation. The patient died as a consequence of a disseminated form of fungal infection. We describe our experience of this rare opportunistic infection and we think that early recognition of the disease could help in proper management.

Modern ECMO: why an ECMO programme in a tertiary care hospital.

Extracorporeal Membrane Oxygenation (ECMO) represents a useful tool to support the lungs and the heart when all conventional therapies failed and the patients are at risk of death. While the Extracorporeal Life Support Organization (ELSO) collects data from different institutions that joined the Registry and reports overall outcome, individual centres often collide with results below expectations, either in adults and in paediatric population. Some authors suggest that poor outcomes could be overcome with a programme dedicated to ECMO, with specialized professionals adequately trained on ECMO and with a consistent number of procedures. In 2012, The IRCCS PSD ECMO Programme was instituted with the specific aim of achieving better results than hitherto obtained. After only 1 year of activity, the results justified the programme, with a better survival rate for each group investigated, particularly in adults, but surprisingly in paediatrics too, where the results were better than what reported by ELSO. Although the number of patients treated with ECMO is still growing up, the effects of the ECMO programme continue to exert a positive action on outcome even now. The present article reports data on survival, blood loss, and blood consumption during ECMO in the last few years at our institution.

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.

Cardiac catheterization and postoperative acute kidney failure in congenital heart pediatric patients.

BACKGROUND: Acute renal failure (ARF) is a severe complication of cardiac operations in pediatric patients. Angiography with the exposure to contrast media is a risk factor for ARF. In the present study, we explored the association between timing of angiography, dose of contrast media, and the incidence of ARF after cardiac operations in pediatric patients. METHODS: We performed a retrospective analysis of prospectively collected data. Angiographic data and other covariates were collected in 277 patients aged ≤12 years receiving angiography and cardiac operations during the same hospital stay. Renal outcome was assessed according to the pediatric Risk, Injury, Failure, Loss of function, End stage score (pRIFLE). RESULTS: One hundred seventy-seven (64%) patients suffered some degree of postoperative renal dysfunction, and 55 (20%) had ARF (pRIFLE stage Failure). Patients with ARF received a significantly (P < 0.001) larger dose of iodine contrast media (4.6 ± 2.6 g/kg) with respect to the other patients (2.8 ± 2.2 g/kg), with a relative risk increase for ARF of 31% per each incremental iodine dose of 1 g/kg at the univariate analysis. A multivariable risk model demonstrated that the risk for ARF is 20 times higher in patients aged younger than 2 years and 3 times higher in case of postoperative low cardiac output. Within this model, the iodine dose on angiography is confirmed as an independent risk factor for ARF, with a relative risk increase for ARF of 16% per each incremental iodine dose of 1 g/kg. CONCLUSIONS: Angiography before cardiac surgery is an important risk factor for ARF in pediatric patients. Being a modifiable risk factor, the contrast media dose should be limited to the lowest possible value, avoiding large doses of iodine which, together with other factors (age and postoperative low cardiac output), concur in the determinism of postoperative ARF.

Bivalirudin-based versus conventional heparin anticoagulation for postcardiotomy extracorporeal membrane oxygenation.

INTRODUCTION: Extracorporeal membrane oxygenation (ECMO) after cardiac operations (postcardiotomy) is commonly used for the treatment of acute heart failure refractory to drug treatment. Bleeding and thromboembolic events are the most common complications of postcardiotomy ECMO. The present study is a retrospective comparison of the conventional heparin-based anticoagulation protocol with a bivalirudin-based, heparin-free protocol. Endpoints of this study are blood loss, allogeneic blood product use, and costs during the ECMO procedure. METHODS: A retrospective study was undertaken in the setting of cardiac surgery, anesthesia, and intensive care departments of a university research hospital. Twenty-one patients (12 adults and nine children) who underwent postcardiotomy ECMO from 2008 through 2011 were retrospectively analyzed. The first consecutive eight patients were treated with heparin-based anticoagulation (H-group) and the next 13 consecutive patients with bivalirudin-based anticoagulation (B-group). The following parameters were analyzed: standard coagulation profile, thromboelastographic parameters, blood loss, allogeneic blood products use, thromboembolic complications, and costs during the ECMO treatment. RESULTS: Patients in the B-group had significantly longer activated clotting times, activated partial thromboplastin times, and reaction times at thromboelastography. The platelet count and antithrombin activity were not significantly different, but in the H-group a significantly higher amount of platelet concentrates, fresh frozen plasma, and purified antithrombin were administered. Blood loss was significantly lower in the B-group, and the daily cost of ECMO was significantly lower in pediatric patients treated with bivalirudin. Thromboembolic complications did not differ between groups. CONCLUSIONS: Bivalirudin as the sole anticoagulant can be safely used for postcardiotomy ECMO, with a better coagulation profile, less bleeding, and allogeneic transfusions. No safety issues were raised by this study, and costs are reduced in bivalirudin-treated patients.

Neoaortic valve and root complex evolution after Ross operation in infants, children, and adolescents.

BACKGROUND: The Ross operation in children and adolescents offers many potential advantages. Concerns have been raised about the long-term development of the neoaortic complex and the risk of dilation. METHODS: Retrospective analysis of prospectively collected follow-up data in a population of patients who underwent Ross operations when they were younger than 18 years old was conducted. Echocardiographic and clinical data, including survival, need for reoperations, and quality of life, were analyzed in 95 patients for a median follow-up of 84 months. RESULTS: The neoaortic root and sinotubular junction demonstrated dilation that exceeded somatic growth. The neoaortic valve grew in a manner that reflected somatic proportions. Freedom from moderate neoaortic root dilation was 100% at 5 years and 77% after 10 years. Freedom from moderate neoaortic valve insufficiency was 86% at 5 years after the Ross procedure and 63% after 10 years. The use of a proximal anastomosis running suture (p = 0.005) and the degree of neoaortic valve insufficiency (p = 0.032) at discharge were independently associated with the degree of neoaortic valve insufficiency at follow-up. Freedom from neoaortic reintervention was 96% at the 5-year follow-up and 80% at the 10-year follow-up. Predictors of neoaortic reintervention were the use of an operative technique other than aortic root replacement (p = 0.002) and the degree of neoaortic valve insufficiency at discharge (p = 0.005). CONCLUSIONS: The Ross operation remains a viable option for children and adolescents with severe aortic valve disease; neoaortic complex dilation occurs but is not directly responsible for neoaortic valve insufficiency, which is the main cause for reoperation.

Central venous oxygen saturation and blood lactate levels during cardiopulmonary bypass are associated with outcome after pediatric cardiac surgery.

INTRODUCTION: Central venous oxygen saturation and blood lactate are different indices of the adequacy of oxygen delivery to the oxygen needs. In pediatric cardiac surgery, lactate level and kinetics during and after cardiopulmonary bypass are associated with outcome variables. The aim of this study was to explore the hypothesis that the lowest central venous oxygen saturation and the peak lactate value during cardiopulmonary bypass, used alone or in combination, may be predictive of major morbidity and mortality in pediatric cardiac surgery. METHODS: We conducted a retrospective analysis of 256 pediatric (younger than 6 years) patients who had undergone cardiac surgery with continuous monitoring of central venous oxygen saturation and serial measurement of blood lactate. RESULTS: Peak lactate was significantly increased when the nadir central venous oxygen saturation was < 68%. Both nadir central venous oxygen saturation and peak lactate during cardiopulmonary bypass were independently associated with major morbidity and mortality, with the same accuracy for major morbidity and a higher accuracy of peak lactate for mortality. A combined index (central venous oxygen saturation < 68% and peak lactate > 3 mmol/L) provided the highest sensitivity and specificity for major morbidity, with a positive predictive value of 89%. CONCLUSIONS: The combination of a continuous monitoring of central venous oxygen saturation and serial measurements of blood lactate during cardiopulmonary bypass may offer a predictive index for major morbidity after cardiac operations in pediatric patients. This study generates the hypothesis that strategies aimed to preserve oxygen delivery during cardiopulmonary bypass may reduce the occurrence of low values of central venous oxygen saturation and elevated lactate levels. Further studies should consider this hypothesis and take into account other time-related factors, such as time of exposure to low values of central venous oxygen saturation and kinetics of lactate formation.

Duration of red blood cell storage and outcomes in pediatric cardiac surgery: an association found for pump prime blood.

INTRODUCTION: Cardiac surgery using cardiopulmonary bypass in newborns, infants and small children often requires intraoperative red blood cell transfusions to prime the circuit and oxygenator and to replace blood lost during surgery. The purpose of this study was to investigate the influence of red blood cell storage time prior to transfusion on postoperative morbidity in pediatric cardiac operations. METHODS: One hundred ninety-two consecutive children aged five years or less who underwent cardiac operations using cardiopulmonary bypass and who received red blood cells for priming the cardiopulmonary bypass circuit comprised the blood-prime group. Forty-seven patients receiving red blood cell transfusions after cardiopulmonary bypass were separately analyzed. Patients in the blood-prime group were divided into two groups based on the duration of storage of the red blood cells they received. The newer blood group included patients who received only red blood cells stored for less than or equal to four days and the older blood group included patients who received red blood cells stored for more than four days. RESULTS: Patients in the newer blood group had a significantly lower rate of pulmonary complications (3.5% versus 14.4%; P = 0.011) as well as a lower rate of acute renal failure (0.8% versus 5.2%; P = 0.154) than patients in the older blood group. Major complications (calculated as a composite score based on pulmonary, neurological, and gastroenterological complications, sepsis and acute renal failure) were found in 6.9% of the patients receiving newer blood and 17.1% of the patients receiving older blood (P = 0.027). After adjusting for other possible confounding variables, red blood cell storage time remained an independent predictor of major morbidity. The same association was not found for patients receiving red blood cell transfusions after cardiopulmonary bypass. CONCLUSIONS: The storage time of the red blood cells used for priming the cardiopulmonary bypass circuit in cardiac operations on newborns and young infants is an independent risk factor for major postoperative morbidity. Pulmonary complications, acute renal failure, and infections are the main complications associated with increased red blood cell storage time.

Morbidity and mortality risk factors in adults with congenital heart disease undergoing cardiac reoperations.

BACKGROUND: Reoperations represent relatively frequent events in adults with congenital heart disease (ACHD). Cardiac operations in these patients present major difficulties in management and technique. Although reoperations in ACHD are becoming increasingly frequent, limited knowledge exists regarding perioperative risk factors. METHODS: The study included 164 ACHD patients who underwent cardiac reoperations between January 2002 and December 2007 at our institution. Preoperative and intraoperative data were analyzed to identify morbidity and mortality risk factors. RESULTS: Reoperations included pulmonary valve implantation or conduit replacement in 60, aortic valve/root procedures in 36, residual atrial or ventricular septal defect closure in 19, and Fontan operation/conversion in 19. Hospital mortality was 3.6%. The mean mechanical ventilation time was 26 hours. Mean intensive care unit stay was 3.1 days. Severe postoperative complications occurred in 24 (15.1%). Cardiopulmonary bypass time (p = 0.001), Fontan operation/conversion (p = 0.001), preoperative hematocrit (p = 0.004), previous number of operations (p = 0.001), and preoperative congestive heart failure (p = 0.021) were associated with severe morbidity. No factor was associated with death. CONCLUSIONS: Reoperations in ACHD are mostly due to right ventricular outflow tract lesions and were associated with a low mortality rate if performed in a center with a considerable activity and a dedicated program. Severe morbidity is relatively frequent and is generally associated with the preoperative (high hematocrit due to cyanosis, congestive heart failure, and the number of previous operations) and operative (Fontan operation/conversion and cardiopulmonary bypass duration) conditions of the patient.

Near-infrared spectroscopy correlates with continuous superior vena cava oxygen saturation in pediatric cardiac surgery patients.

BACKGROUND: Cerebral regional oxygen saturation (rSO(2)) measured with near-infrared spectroscopy (NIRS) has a well-proven clinical utility. A goal-oriented treatment based on the rSO(2) resulted in a significant reduction in major morbidity and in a shortening of postoperative hospital stay in patients undergoing coronary revascularization. In this study, we have compared the values of superior vena cava saturation (ScvO(2)) continuously measured with a Pediasat catheter and the corresponding NIRS rSO(2) values obtained during cardiac operations in pediatric patients. METHODS: This was a prospective observational study enrolling fifteen pediatric patients (age: 6 days-7 years) undergoing cardiac operations. ScvO(2) data obtained with the Pediasat during the operation were compared with simultaneously recorded NIRS rSO(2) values. RESULTS: One hundred and seventeen matched sets of data were obtained during the operation. ScvO(2) continuously measured with the Pediasat was significantly correlated with the corresponding NIRS rSO(2) values. However, there was a constant positive bias (ScvO(2) values were higher than NIRS rSO(2) values) of 5.6%, with a precision of 10.4%. Time-related percentage changes of NIRS rSO(2) were significantly correlated with the corresponding ScvO(2) percentage changes. A decrease in ScvO(2) is predictive for a decrease in rSO(2) with a sensitivity of 73.7% and a specificity of 85.7%. CONCLUSIONS: The continuous measurement of ScvO(2) values obtained by the Pediasat may provide useful information about the metabolic conditions of the brain during cardiac operations in pediatric patients if considered as percentage changes. Absolute values of ScvO(2) tend to overestimate the correspondent rSO(2) values.

Continuous monitoring of central venous oxygen saturation (Pediasat) in pediatric patients undergoing cardiac surgery: a validation study of a new technology.

OBJECTIVE: Mixed venous oxygen saturation and central venous oxygen saturation are considered possible indicators of the adequacy of oxygen delivery with respect to the oxygen needs of critically ill adult and pediatric patients. The present study was aimed at validating the accuracy of a new technology (Pediasat central venous catheter) in providing a continuous measurement of the central venous oxygen saturation in pediatric patients. DESIGN: A prospective observational study. PARTICIPANTS: Thirty pediatric patients (age, 6 days-9 years) undergoing cardiac operations. Data obtained with the Pediasat during and after the operation were compared with simultaneously collected venous blood samples analyzed with standard laboratory techniques. SETTING: A clinical research hospital. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A Bland and Altman analysis was performed on 30 matched sets of data collected before cardiopulmonary bypass, during cardiopulmonary bypass, and during the intensive care unit stay. Before cardiopulmonary bypass, there was a bias of 0.003, with lower and upper limits of agreement, -5.84 and 5.84 (percentage error, 17.3%). During cardiopulmonary bypass, the bias was 0.57 and lower and upper limits of agreement were -7.7 and 8.7 (percentage error, 23.2%). At 2 hours after the arrival in the intensive care unit, the bias was -0.6 and the lower and upper limits of agreement were -8 and 6.8 (percentage error, 20.3%). CONCLUSIONS: Because of the minimal bias and the acceptable value of percentage error, the Pediasat may be considered as an accurate tool for the continuous measurement of the central venous oxygen saturation in neonates and pediatric patients during and after cardiac operations.

The Ross procedure in adults: long-term follow-up and echocardiographic changes leading to pulmonary autograft reoperation.

BACKGROUND: This is a clinical investigation of the mid- to long-term follow-up of the Ross procedure in adult patients. The primary end point is to explore the incidence and risk factors for a reoperation on the pulmonary autograft. The secondary end points are to explore the incidence of neoaortic root dilation and valve regurgitation, and the echocardiographic profile leading to a reoperation. METHODS: Ross operations were done in 110 adults who received at least two echocardiographic examinations for a mean follow-up time of 82 months (range, 5 to 155 months). Kaplan-Meier and Cox regression analyses were applied to assess freedom from events and risk factors for events. RESULTS: Freedom from reoperation on the pulmonary autograft, neoaortic root dilation, and moderate-severe neoaortic valve regurgitation were, respectively, 91.4%, 50%, and 70% at 12 years. The main risk factor for a reoperation was the degree of neoaortic valve regurgitation within the first 2 years of follow-up. Patients requiring an early (4 years) reoperation had severe neoaortic root dilation and severe neoaortic valve regurgitation. The left ventricular end-diastolic diameter at the third year of follow-up was a risk factor for late reoperation. CONCLUSIONS: The Ross operation in adults is a safe procedure with good clinical results in mid- to long-term follow-up. Early reoperations are due to early neoaortic valve regurgitation, wheras late reoperations are due to progressive neoaortic root dilation.

Oxygen metabolism during and after cardiac surgery: role of CPB.

BACKGROUND: Cardiopulmonary bypass (CPB) has been reported to increase oxygen metabolism and to influence the relation between oxygen consumption (VO(2)) and delivery (DO(2)) in the early hours after cardiac surgery. To investigate the role of CPB, we studied oxygen metabolism in coronary artery bypass procedures performed on-pump (CABG) and off-pump (OPCAB). METHODS: Twenty-five patients were randomized to undergo CABG (n = 14) or OPCAB (n = 11). All patients received the same anesthetic management. Oxygen metabolism variables were assessed before induction of anesthesia and up to 18-hours after surgery. RESULTS: At baseline, before induction of anesthesia, there were no differences between CABG and OPCAB in oxygen consumption (VO(2)), delivery (DO(2)), or extraction (ExO(2)). After surgery VO(2) and ExO(2) increased in both groups, while DO(2) decreased. No significant differences between CABG and OPCAB were detected in postoperative VO(2), DO(2), and ExO(2) levels. The relation between VO(2) and DO(2) was very similar in CABG and OPCAB patients throughout the study, and no significant differences were detected in slopes and intercepts of the regression lines between CABG and OPCAB at all time points. There was, however, a significant effect of time on the relation between VO(2) and DO(2): this relation was stronger in the postoperative period, and the slope of this relation increased over time as well. CONCLUSIONS: A hypermetabolic state and progressive and significant increases in the strength of the relationship between VO(2) and DO(2) and in the slope of this relationship occur after both CABG and OPCAB. Cardiopulmonary bypass is not responsible for these changes in oxygen metabolism.