A novel interpretative tool for early prediction of low cardiac output syndrome after valve surgery: online machine learning models.

OBJECTIVE: Low cardiac output syndrome (LCOS) is a severe complication after valve surgery, with no uniform standard for early identification. We developed interpretative machine learning (ML) models for predicting LCOS risk preoperatively and 0.5 h postoperatively for intervention in advance. METHODS: A total of 2218 patients undergoing valve surgery from June 2019 to Dec 2021 were finally enrolled to construct preoperative and postoperative models. Logistic regression, support vector machine (SVM), random forest classifier, extreme gradient boosting, and deep neural network were executed for model construction, and the performance of models was evaluated by area under the curve (AUC) of the receiver operating characteristic and calibration curves. Our models were interpreted through SHapley Additive exPlanations, and presented as an online tool to improve clinical operability. RESULTS: The SVM algorithm was chosen for modeling due to better AUC and calibration capability. The AUCs of the preoperative and postoperative models were 0.786 (95% CI 0.729-0.843) and 0.863 (95% CI 0.824-0.902), and the Brier scores were 0.123 and 0.107. Our models have higher timeliness and interpretability, and wider coverage than the vasoactive-inotropic score, and the AUC of the postoperative model was significantly higher. Our preoperative and postoperative models are available online at http://njfh-yxb.com.cn:2022/lcos. CONCLUSIONS: The first interpretable ML tool with two prediction periods for online early prediction of LCOS risk after valve surgery was successfully built in this study, in which the SVM model has the best performance, reserving enough time for early precise intervention in critical care.

Procedure-Specific Relationships Between Postoperative Troponin T and a Composite of Mortality and Low Cardiac Output Syndrome: A Retrospective Cohort Analysis.

BACKGROUND: Myocardial injury after coronary artery bypass grafting (CABG) is defined as troponin concentrations >10 times 99th percentile upper reference limit (URL) according to the Fourth Universal Definition. However, troponin concentrations after non-CABG cardiac surgery which indicate greater-than-expected myocardial injury and increased risk for complications remain unclear. Our goal was to assess procedure-specific relationships between troponin T and a composite outcome of low cardiac output syndrome and in-hospital mortality in cardiac surgical patients. METHODS: Patients having cardiac surgery between January 2010 and December 2017 were categorized into 4 groups by procedure: (1) CABG; (2) mitral valve repair; (3) aortic valve repair/replacement (AVR); (4) mitral valve replacement (MVR) or CABG + valve surgeries. Exclusion criteria were elevated preoperative troponin T, preoperative kidney failure, circulatory arrest, or preoperative/planned mechanical circulatory support. Logistic regression was used to assess the association between troponin T and composite outcome, both overall and by procedure, including assessment of the interaction between procedure and troponin T on outcome. RESULTS: Among 10,253 patients, 37 (0.4%) died and 393 (3.8%) developed the primary outcome. Troponin T concentrations differed by procedure (P < .001). Compared to CABG, AVR had 0.53 (99.2% confidence interval [CI], 0.50-0.56; unadjusted P < .001) times lower troponin T concentrations, while MVR/CABG + valve were 1.54 (99.2% CI, 1.45-1.62, unadjusted P < .001) times higher. There were linear relationships between log2 troponin T concentration and log odds mortality/low cardiac output syndrome. The (unadjusted) relationships were parallel for various types of surgery (interaction P = .59), but at different levels of the outcome. CONCLUSIONS: The relative increase in odds for mortality/low cardiac output syndrome per a similar increase in troponin T concentrations did not differ among cardiac surgical procedures, but the absolute troponin T concentrations did. Troponin concentrations should thus be interpreted in context of surgical procedure.

N-Terminal Pro-B-Type Natriuretic Peptide as a Predictor of Adverse Outcomes After Off-Pump Coronary Artery Bypass Surgery: A Prospective Study.

BACKGROUND: The strength of association between preoperative natriuretic peptide levels and adverse outcomes after cardiac surgery recently has been studied in different research, but results still are diversely variable. METHODS: Sixty-five consecutive patients undergoing elective off-pump coronary artery bypass grafting prospectively were recruited. Preoperative levels of NTproBNP were measured in venous blood samples collected before induction of anesthesia. RESULTS: The average age was 57.62 ± 7.21. Of the patients, 86.15% were male. Euro-scoreII averaged 1.76 ± 0.34. The mean preoperative NTproBNP levels were 312.41 ± 329.93 pg/mL. Only two patients died (3%). Three patients required prolonged mechanical ventilation (4.6%). Four patients (6%) suffered from new onset postoperative AF. Five patients (7.6%) had low cardiac output, of which three needed IABP, and four patients (6%) had postoperative myocardial infarction. The mean ICU stay was 3.37 ± 0.84 days, and the mean hospital stay was 6.38 ± 1.3 days. There were no significant differences in preoperative NTproBNP levels in patients who had or didn't have any of the postoperative complications or in-hospital mortality (P > .05). CONCLUSION: Our study showed no significant correlation between preoperative NTproBNP levels and postoperative low cardiac output, atrial fibrillation, postoperative myocardial infarction, length of ICU stay, prolonged mechanical ventilation, length of hospital stay as well as in-hospital mortality following elective off-pump CABG. Therefore, more prospective specific studies are needed to delineate the role of preoperative natriuretic peptides as significant predictors of poor outcomes after CABG surgery.

The multivariable prognostic models for severe complications after heart valve surgery.

BACKGROUND: To provide multivariable prognostic models for severe complications prediction after heart valve surgery, including low cardiac output syndrome (LCOS), acute kidney injury requiring hemodialysis (AKI-rH) and multiple organ dysfunction syndrome (MODS). METHODS: We developed multivariate logistic regression models to predict severe complications after heart valve surgery using 930 patients collected retrospectively from the first affiliated hospital of Sun Yat-Sen University from January 2014 to December 2015. The validation was conducted using a retrospective dataset of 713 patients from the same hospital from January 2016 to March 2017. We considered two kinds of prognostic models: the PRF models which were built by using the preoperative risk factors only, and the PIRF models which were built by using both of the preoperative and intraoperative risk factors. The least absolute shrinkage selector operator was used for developing the models. We assessed and compared the discriminative abilities for both of the PRF and PIRF models via the receiver operating characteristic (ROC) curve. RESULTS: Compared with the PRF models, the PIRF modes selected additional intraoperative factors, such as auxiliary cardiopulmonary bypass time and combined tricuspid valve replacement. Area under the ROC curves (AUCs) of PRF models for predicting LCOS, AKI-rH and MODS are 0.565 (0.466, 0.664), 0.688 (0.62, 0.757) and 0.657 (0.563, 0.751), respectively. As a comparison, the AUCs of the PIRF models for predicting LOCS, AKI-rH and MODS are 0.821 (0.747, 0.896), 0.78 (0.717, 0.843) and 0.774 (0.7, 0.847), respectively. CONCLUSIONS: Adding the intraoperative factors can increase the predictive power of the prognostic models for severe complications prediction after heart valve surgery.

Preoperative Pericardial Effusion is Associated with Low Cardiac Output Syndrome After Pericardiectomy for Constrictive Pericarditis.

BACKGROUND: Low cardiac output syndrome is the main cause of death after pericardiectomy. METHODS: Patients who underwent pericardiectomy for constrictive pericarditis from January 2009 to October 2020 at our hospital were included in the study. Histopathologic studies of pericardium tissue from every patient were performed. All survivors were followed up. RESULTS: Ninety-two consecutive patients underdoing pericardiectomy were included in the study. The incidence of postoperative low cardiac output syndrome was 10.7% (10/92). There were five operative deaths. Mortality and incidence of LCOS in the group with pericardial effusion were significantly higher than those in the group without pericardial effusion. Tuberculosis of the pericardium (60/92, 65.2%) was the most common histopathologic finding in this study. Both univariate and multivariate analyses showed that preoperative pericardial effusion is associated with increased rate of low cardiac output syndrome. Eighty-five survivors were in NYHA class I (85/87, 97.7%), and two were in class II (2/87, 2.3%) at the latest follow up. CONCLUSIONS: Preoperative pericardial effusion is associated with low cardiac output syndrome after pericardiectomy. Tuberculosis of the pericardium was the most common histopathologic finding in this study. For constrictive pericarditis caused by tuberculous bacteria, systematic antituberculosis drugs should be given. Preoperative pericardial effusion is associated with increased rate of low cardiac output syndrome. Perfect preoperative preparation is very important to reduce the incidence of postoperative low cardiac output syndrome and mortality. It is very important to use a large dose of diuretics with cardiotonic or vasopressor in a short time after the operation.

Use of Impella CP Device in Off-Pump Coronary Artery Bypass Graft Surgery.

Off-pump coronary artery bypass grafting (OPCABG) may be performed on patients with high surgical risk who are poor candidates for traditional mechanical circulatory support. Hemodynamic support with micro-axial mechanical circulatory devices has been performed with limited but promising results.We report a case of a 66-year-old male with multiple comorbidities and low cardiac output undergoing OPCABG. Impella CP device was deployed for "in-pump" support during surgical coronary revascularization resulting in intraoperative stability and uncomplicated post-operative recovery.Previous reports have described the use of the Impella Recover LP 5.0 device for use during OPCABG. We describe the successful and safe perioperative use of the Impella CP device. Despite lower flow rates, adequate support was achieved and the transfemoral cannulation and smaller outer diameter than the Impella 5.0 device may decrease the risk of complications and expedite recovery. Further research will be necessary to determine the optimal perioperative hemodynamic support strategy to offer hemodynamically unstable, high, and prohibitive risk patients.

Semi-urgent pulmonary vein isolation using cryoballoon for haemodynamically unstable atrial fibrillation storm in a patient with low cardiac output syndrome: a case report.

BACKGROUND: Atrial fibrillation and heart failure are common coexisting conditions requiring hospitalisation for heart failure and death. Pulmonary vein isolation is a well-established option for symptomatic atrial fibrillation and for atrial fibrillation concomitant with heart failure with reduced left ventricular ejection fraction. Recently, pulmonary vein isolation using cryoballoon showed non-inferiority to radiofrequency ablation with respect to the treatment of patients with drug-refractory paroxysmal atrial fibrillation. However, the effectiveness of acute-phase rhythm control by semi-urgent pulmonary vein isolation using cryoballoon in patients with haemodynamically unstable atrial fibrillation storm accompanied with low cardiac output syndrome is unclear. Herein, we present a case in which semi-urgent pulmonary vein isolation using cryoballoon was effective for acute-phase rhythm control against drug-resistant and haemodynamically unstable repetitive atrial fibrillation tachycardia accompanied with low cardiac output syndrome. CASE PRESENTATION: A 57-year-old man was hospitalised for New York Heart Association functional class 4 heart failure with atrial fibrillation tachycardia and reduced left ventricular ejection fraction of 20% accompanied with low cardiac output syndrome-induced liver damage. The haemodynamics collapsed during atrial fibrillation tachycardia, which had become resistant to intravenous amiodarone and repeated electrical cardioversions. In addition to atrial fibrillation, atrial tachycardia and common-type atrial flutter appeared on day 3. Multiple organ failure progressed gradually due to haemodynamically unstable atrial fibrillation tachycardia storm accompanied with low cardiac output syndrome. On day 4, to focus on treatment of heart failure and multiple organ failure, semi-urgent rescue pulmonary vein isolation using cryoballoon to atrial fibrillation and cavotricuspid isthmus ablation to common-type atrial flutter were performed for acute-phase rhythm control. Soon after the ablation procedure, atrial fibrillation and common-type atrial flutter were lessened, and sinus rhythm was restored. A stable haemodynamics was successfully achieved with the improvement of hepatorenal function. The patient was discharged on day 77 without complications. CONCLUSIONS: This case demonstrates that acute-phase rhythm control by semi-urgent pulmonary vein isolation using cryoballoon could be a treatment option in patients with haemodynamically unstable atrial fibrillation tachycardia storm accompanied with low cardiac output syndrome, which is refractory to cardioversion and drug therapy.

[Low cardiac output syndrome score to evaluate postoperative cardiac surgery patients in a pediatric intensive care unit]. / Çocuk yogun bakim ünitesinde kardiyak cerrahi sonrasi hastalarin degerlendirilmesinde kullanilan düsük kardiyak debi sendromu skorlamasi.

OBJECTIVE: There is no clear consensus regarding the definition of low cardiac output syndrome (LCOS) or the follow-up of this patient group. Given this lack of a clinical definition, the aim of this study was to use a LCOS score (LCOSs) similar to the low cardiac output score previously presented in the literature and evaluate the relationship between a high LCOSs and poor clinical outcome. METHODS: A total of 54 patients were prospectively evaluated after cardiac surgery. The LCOSs was used to evaluate the deve-lopment of low cardiac output. Each parameter was scored as 1 point. The score was calculated every hour for 24 hours postoperatively and the highest score was recorded as the peak score (pLOCSs). The LOCSs at the time of admission to the pediatric intensive care unit, at the 4th, 8th, and 16th hour were recorded and a cumulative score (cLOCSs) score was calculated. RESULTS: The mean age of the patients was 49.40±53.15 months and 24.07% had LOCS. In the group with LCOS, the cLOCSs, vasoactive-inotropic score (VIS), lactate mean, aortic clamp time, and the total cardiopulmonary bypass time were significantly higher. In this study, a significant and positive correlation was found between the cLOCSs and pLOCSs and the length of hospital stay, length of stay in the pediatric intensive care unit, VIS, lactate mean, and aortic clamp duration. CONCLUSION: The objective of this study was to draw attention to the potential use of a common language in the care of critical pediatric patients undergoing cardiac surgery with a previously defined scoring method that includes parameters indicating poor perfusion in the patient.

Risk factors for low cardiac output syndrome in children with congenital heart disease undergoing cardiac surgery: a retrospective cohort study.

BACKGROUND: Low cardiac output syndrome (LCOS) is an important complication of cardiac surgery. It is associated with increased morbidity and mortality. The incidence of LCOS after surgery is high in patients with congenital heart disease (CHD). Therefore, determining the risk factors of LCOS has clinical significance for the management of CHD. This study aimed to analyze the risk factors of LCOS. METHODS: We conducted a retrospective analysis of children with CHD who underwent cardiac surgery at Shanghai Children's Medical Center between January 1, 2014, and December 31, 2017. Demographic characteristics and baseline data were extracted from the health data resource center of the hospital, which integrates clinical routine data including medical records, diagnoses, orders, surgeries, laboratory tests, imaging, nursing, and other subsystems. Logistic regressions were performed to analyze the risk factors of LCOS. RESULTS: Overall, 8660 infants with CHD were included, and 864 (9.98%) had LCOS after surgery. The multivariate regression analysis identified that age (OR 0.992, 95% CI: 0.988-0.997, p = 0.001), tricuspid regurgitation (1.192, 1.072-1.326, p = 0.001), Risk Adjustment in Congenital Heart Surgery-1 risk grade (1.166, 1.011-1.345, p = 0.035), aortic shunt (left-to-right: 1.37, 1.005-1.867, p = 0.046; bi-directional: 1.716, 1.138-2.587, p = 0.01), atrial shunt (left-to-right: 1.407, 1.097-1.805, p = 0.007; right-to-left: 3.168, 1.944-5.163, p < 0.001; bi-directional: 1.87, 1.389-2.519, p < 0.001), ventricular level shunt (left-to-right: 0.676, 0.486-0.94, p = 0.02; bi-directional: 2.09, 1.611-2.712, p < 0.001), residual shunt (3.489, 1.502-8.105, p = 0.004), left ventricular outflow tract obstruction (3.934, 1.673-9.254, p = 0.002), right ventricular outflow tract obstruction (3.638, 1.225-10.798, p = 0.02), circulating temperature (mild hypothermia: 1.526, 95% CI: 1.205-1.934, p < 0.001; middle and low temperature: 1.738, 1.236-2.443, p = 0.001), duration of cardiopulmonary bypass (1.009, 1.006-1.012, p < 0.001), myocardial preservation using histidine-tryptophan-ketoglutarate (1.677, 1.298-2.167, p < 0.001), and mitral insufficiency (1.714, 1.239-2.37, p < 0.001) were independent risk predictors of LCOS. CONCLUSIONS: The incidence of postoperative LCOS in CHD children remains high. Circulation temperature, myocardial preservation using histidine-tryptophan-ketoglutarate, and usage of residual shunt after surgery were independent risk predictors for LCOS.

Ventricular-Arterial Coupling in Children and Infants With Congenital Heart Disease After Cardiopulmonary Bypass Surgery: Observational Study.

OBJECTIVES: Ventricular-arterial coupling represents the interaction between the left ventricle and the arterial system. Ventricular-arterial coupling is measured as the ratio between arterial elastance and ventricular end-systolic elastance. Scant information is available in critically ill children about these variables. The aim of this study was to prospectively assess ventricular-arterial coupling after pediatric cardiac surgery and evaluate its association with other commonly recorded hemodynamic parameters. DESIGN: Single-center retrospective observational study. SETTING: Pediatric cardiac surgery operating room. PATIENTS: Children undergoing corrective cardiac surgery. INTERVENTIONS: Hemodynamic monitoring with transesophageal echocardiography. MEASUREMENTS AND MAIN RESULTS: Twenty-seven patients with biventricular congenital heart disease, who underwent elective cardiac surgery with cardiopulmonary bypass, were enrolled before operating room discharge. Chen single-beat modified method was applied to calculate ventricular-arterial coupling. The median arterial elastance and end-systolic elastance values were 5.9 mm Hg/mL (2.2-9.3 mm Hg/mL) and 4.3 mm Hg/mL (1.9-8.3 mm Hg/mL), respectively. The median ventricular- arterial coupling was 1.2 (1.1-1.6). End-systolic elastance differences between patients with a ventricular-arterial coupling below (low ventricular-arterial coupling) and above (high ventricular-arterial coupling) the median value were -5.2 (95% CI, -6.28 to -0.7; p = 0.008). Differently, arterial elastance differences were -2.1 (95% CI, -5.7 to 1.6; p = 0.19). Ventricular-arterial coupling showed a significant association with pre-ejection time (r, 0.44; p = 0.02), total ejection time (r, -0.41; p = 0.003), cardiac cycle efficiency (r, -0.46; p = 0.02), maximal delta pressure over delta time (r, -0.44; p = 0.02), ejection fraction (r, -0.57; p = 0.01), and systemic vascular resistances indexed (0.56; p = 0.003). After adjustment, total ejection time (p = 0.001), pre-ejection time (p = 0.02), and ejection fraction (p = 0.001) remained independently associated with ventricular-arterial coupling. CONCLUSIONS: Median ventricular-arterial coupling values in children after cardiac surgery appear high (above 1). Uncoupling was particularly evident in high ventricular-arterial coupling patients who showed the lowest end-systolic elastance values (but not significantly different arterial elastance values) compared with low ventricular-arterial coupling. Ventricular-arterial coupling appears to be inversely proportional to pre-ejection time, total ejection time, and ejection fraction.

Identification of Low Cardiac Output Syndrome at the Bedside: A Pediatric Cardiac Intensive Care Unit Survey.

BACKGROUND: Low cardiac output syndrome is a transient constellation of signs and symptoms that indicate the heart's inability to supply sufficient oxygen to tissues and end-organs to meet metabolic demand. Because the term lacks a standard clinical definition, the bedside diagnosis of this syndrome can be difficult. OBJECTIVE: To evaluate concordance among pediatric cardiac intensive care unit nurses in their identification of low cardiac output syndrome in pediatric patients after cardiac surgery. METHODS: An anonymous survey was distributed to 69 pediatric cardiac intensive care unit nurses. The survey described 10 randomly selected patients aged 6 months or younger who had undergone corrective or palliative cardiac surgery at a freestanding children's hospital in a tertiary academic center. For each patient, data were presented corresponding to 5 time points (0, 6, 12, 18, and 24 hours postoperatively). The respondent was asked to indicate whether the patient had low cardiac output syndrome (yes or no) at each time point on the basis of the data presented. RESULTS: The response rate was 46% (32 of 69 nurses). The overall Fleiss k value was 0.30, indicating fair agreement among raters. When the results were analyzed by years of experience, agreement remained only slight to fair. CONCLUSIONS: Regardless of years of experience, nurses have difficulty agreeing on the presence of low cardiac output syndrome. Further research is needed to determine whether the development of objective guidelines could improve recognition and facilitate communication between the pediatric cardiac intensive care unit nurse and the medical team.

The Inadequate Oxygen Delivery Index and Low Cardiac Output Syndrome Score As Predictors of Adverse Events Associated With Low Cardiac Output Syndrome Early After Cardiac Bypass.

OBJECTIVES: To evaluate the effectiveness of two scoring systems, the inadequate oxygen delivery index, a risk analytics algorithm (Etiometry, Boston, MA) and the Low Cardiac Output Syndrome Score, in predicting adverse events recognized as indicative of low cardiac output syndrome within 72 hours of surgery. DESIGN: A retrospective observational pair-matched study. SETTING: Tertiary pediatric cardiac ICU. PATIENTS: Children undergoing cardiac bypass for congenital heart defects. Cases experienced an adverse event linked to low cardiac output syndrome in the 72 hours following surgery (extracorporeal membrane oxygenation, renal replacement therapy, cardiopulmonary resuscitation, and necrotizing enterocolitis) and were matched with a control patient on criteria of procedure, diagnosis, and age who experienced no such event. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of a total 536 bypass operations in the study period, 38 patients experienced one of the defined events. Twenty-eight cases were included in the study after removing patients who suffered an event after 72 hours or who had insufficient data. Clinical and laboratory data were collected to derive scores for the first 12 hours after surgery. The inadequate oxygen delivery index was calculated by Etiometry using vital signs and laboratory data. A modified Low Cardiac Output Syndrome Score was calculated from clinical and therapeutic markers. The mean inadequate oxygen delivery and modified Low Cardiac Output Syndrome Score were compared within each matched pair using the Wilcoxon signed-rank test. Inadequate oxygen delivery correctly differentiated adverse events in 13 of 28 matched pairs, with no evidence of inadequate oxygen delivery being higher in cases (p = 0.71). Modified Low Cardiac Output Syndrome Score correctly differentiated adverse events in 23 of 28 matched pairs, with strong evidence of a raised score in low cardiac output syndrome cases (p < 0.01). CONCLUSIONS: Although inadequate oxygen delivery is an Food and Drug Administration approved indicator of risk for low mixed venous oxygen saturation, early postoperative average values were not linked with medium-term adverse events. The indicators included in the modified Low Cardiac Output Syndrome Score had a much stronger association with the specified adverse events.

Severe Dizziness and Syncope After HeartMate 3 Implantation Requiring Pump Exchange.

Implantation of the HeartMate 3 (HM3) left ventricular assist device (Abbott Laboratories, Lake Bluff, IL) continues to increase as the results of European and U.S. clinical trials become available. Although the large trials adequately capture the more common and expected outcomes, rare and unexpected clinical complications will continue to appear with higher volumes of implantation. This report describes a rare complication of severe refractory postural dizziness and syncope after successful implantation of an HM3 in a patient who ultimately required pump exchange to a HeartWare HVAD (HeartWare, Framingham, MA) for resolution of symptoms.

Performance de enfermeiros não peritos na classificação dos indicadores clínicos do débito cardíaco diminuído / Non-expert nurses' performance in classifying clinical indicators of decreased cardiac output / Rendimiento de enfermeros no expertos en la clasificación de los indicadores clínicos de la disminución del gasto cardíaco

Objetivo: verificar performance de enfermeiros assistenciais em cardiologia, não peritos em diagnóstico de enfermagem, em classificar indicadores clínicos do débito cardíaco diminuído (DCD), tendo por base os achados de um estudo realizado com peritos. Método: estudo quantitativo, transversal, de acurácia diagnóstica. Realizado com 23 enfermeiros atuantes em unidades de cuidados intensivos de hospital público estadual do Rio de Janeiro, especializado em cardiologia. As medidas de performance utilizadas foram: eficiência, taxa de superestimação e taxa de subestimação. Resultados: a taxa média de eficiência de classificação dos indicadores clínicos do DCD foi de 65,9%. Na comparação intergrupos, a taxa de subestimação foi maior para os que usam diagnóstico na prática clínica (26,5%) e a de superestimação para os que não usam (49,9%). Conclusão: há adequação na eficiência dos enfermeiros, com atuação clínica em enfermagem cardiológica, não peritos em classificar um conjunto de indicadores de forma similar a peritos.

Objective: to assess the performance of cardiology nurses, non-experts in nursing diagnosis, in classifying clinical indicators of decreased cardiac output, based on the findings of a study of experts. Method: this quantitative, cross-sectional study of diagnostic accuracy examined 23 nurses working in intensive care units of a Rio de Janeiro State public specialist cardiology hospital. The performance measures used were: efficiency, overestimation rate, and underestimation rate. Results: the average rating for efficiency in classifying clinical indicators of decreased cardiac output was 65.9%. In intergroup comparison, the underestimation rate was higher (26.5%) among those who used diagnosis in clinical practice, while overestimation was higher (49.9%) among those who did not use it. Conclusion: non-expert nurses working in clinical cardiology nursing were adequately efficient in classifying a set of indicators similarly to experts.

Objetivo: verificar el rendimiento del enfermero asistencial en cardiología, no experto en diagnóstico de enfermería, en la clasificación de indicadores clínicos del bajo gasto cardíaco, basado en los hallazgos de un estudio llevado a cabo con expertos. Método: estudio cuantitativo, transversal, de precisión diagnóstica. Realizado junto a 23 enfermeros que trabajan en unidades de cuidados intensivos de un hospital público estadual de Río de Janeiro, especializado en cardiología. Las medidas de rendimiento utilizadas fueron: eficiencia, tasa de sobreestimación y tasa subestimación. Resultados: la tasa media de eficiencia de los indicadores clínicos del bajo gasto cardíaco fue 65,9%. En la comparación intergrupal, la tasa de subestimación fue mayor para aquellos que utilizan el diagnóstico en la práctica clínica (26,5%) y la sobreestimación de los que no lo utilizan (49,9%). Conclusión: existe adecuación de la eficiencia de los enfermeros con el trabajo clínico en enfermería cardiológica, no expertos en clasificar un conjunto de indicadores de manera similar a los expertos.

Correlations between near-infrared spectroscopy, perfusion index, and cardiac outputs in extremely preterm infants in the first 72 h of life.

Haemodynamic assessment during the transitional period in preterm infants is challenging. We aimed to describe the relationships between cerebral regional tissue oxygen saturation (CrSO2), perfusion index (PI), echocardiographic, and clinical parameters in extremely preterm infants in their first 72 h of life. Twenty newborns born at < 28 weeks of gestation were continuously monitored with CrSO2 and preductal PI. Cardiac output was measured at H6, H24, H48, and H72. The median gestational age and birth weight were 25.0 weeks (24-26) and 750 g (655-920), respectively. CrSO2 and preductal PI had r values < 0.35 with blood gases, lactates, haemoglobin, and mean blood pressure. Cardiac output significantly increased over the 72 h of the study period. Fifteen patients had at least one episode of low left and/or right ventricular output (RVO), during which there was a strong correlation between CrSO2 and superior vena cava (SVC) flow (at H6 (r = 0.74) and H24 (r = 0.86)) and between PI and RVO (at H6 (r = 0.68) and H24 (r = 0.92)). Five patients had low SVC flow (≤ 40 mL/kg/min) at H6, during which PI was strongly correlated with RVO (r = 0.98). CONCLUSION: CrSO2 and preductal PI are strongly correlated with cardiac output during low cardiac output states. What is Known: • Perfusion index and near-infrared spectroscopy are non-invasive tools to evaluate haemodynamics in preterm infants. • Pre- and postductal perfusion indexes strongly correlate with left ventricular output in term infants, and near-infrared spectroscopy has been validated to assess cerebral oxygenation in term and preterm infants. What is New: • Cerebral regional tissue oxygen saturation and preductal perfusion index were strongly correlated with cardiac output during low cardiac output states. • The strength of the correlation between cerebral regional tissue oxygen saturation, preductal perfusion index, and cardiac output varied in the first 72 h of life, reflecting the complexity of the transitional physiology.

Intramural Left Coronary Artery in Truncus Arteriosus.

An intramural coronary artery in the setting of truncus arteriosus (common arterial trunk) is an uncommon association. Following an uneventful surgical repair, a neonate developed a low cardiac output state deteriorating into cardiac arrest shortly after arrival into the intensive care unit, requiring extracorporeal membrane oxygenation support. Echocardiography and angiography showed occlusion of the left coronary artery, prompting emergency surgical reexploration. A "slit-like" orifice with an intramural left coronary artery was successfully unroofed, allowing full recovery. Full definition of the proximal coronary anatomy beyond the orifices should be investigated preoperatively in truncus arteriosus, as a missed intramural segment could lead to significant morbidity or mortality.

Cardiac Biomarkers of Low Cardiac Output Syndrome in the Postoperative Period After Congenital Heart Disease Surgery in Children.

INTRODUCTION AND OBJECTIVES: To assess the predictive value of atrial natriuretic peptide, ß-type natriuretic peptide, copeptin, mid-regional pro-adrenomedullin (MR-proADM) and cardiac troponin I (cTn-I) as indicators of low cardiac output syndrome in children with congenital heart disease undergoing cardiopulmonary bypass (CPB). METHODS: After corrective surgery for congenital heart disease under CPB, 117 children (aged 10 days to 180 months) were enrolled in a prospective observational pilot study during a 2-year period. The patients were classified according to whether they developed low cardiac output syndrome. Biomarker levels were measured at 2, 12, 24, and 48 hours post-CPB. The clinical data and outcome variables were analyzed by a multiple logistic regression model. RESULTS: Thirty-three (29%) patients developed low cardiac output syndrome (group 1) and the remaining 84 (71%) patients were included in group 2. cTn-I levels >14 ng/mL at 2hours after CPB (OR, 4.05; 95%CI, 1.29-12.64; P=.016) and MR-proADM levels>1.5 nmol/L at 24hours following CPB (OR, 15.54; 95%CI, 4.41-54.71; P<.001) were independent predictors of low cardiac output syndrome. CONCLUSIONS: Our results suggest that cTn-I at 2hours post-CPB is, by itself, an evident independent early predictor of low cardiac output syndrome. This predictive capacity is, moreover, reinforced when cTn-I is combined with MR-proADM levels at 24hours following CPB. These 2 cardiac biomarkers would aid in therapeutic decision-making in clinical practice and would also enable clinicians to modify the type of support to be used in the pediatric intensive care unit.

Central Venous to Arterial CO2 Difference After Cardiac Surgery in Infants and Neonates.

OBJECTIVES: Venous to arterial CO2 difference correlates with cardiac output in critically ill adults, but its utility in pediatric patients is unclear. We sought to correlate venous to arterial CO2 difference with other cardiac output surrogates (arteriovenous oxygen saturation difference, central venous oxygen saturation, and lactate) and investigate its capacity to predict poor outcomes associated with low cardiac output (low cardiac output syndrome) in infants after cardiac surgery with cardiopulmonary bypass. DESIGN: Retrospective chart review. Poor outcome was defined as any inotrope score greater than 15; death, cardiac arrest, extracorporeal membrane oxygenation; and unplanned surgical reintervention. SETTING: Pediatric cardiovascular ICU. PATIENTS: One hundred thirty-nine infants less than 90 days who underwent cardiopulmonary bypass, from October 2012 to May 2015. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Two hundred ninety-six arterial and venous blood gas pairs from admission (n = 139), 6 (n = 62), 12 (n = 73), and 24 hours (n = 22) were included in analysis. For all pairs, venous to arterial CO2 difference was moderately correlated with arteriovenous oxygen saturation difference (R = 0.53; p < 0.01) and central venous oxygen saturation (R = -0.43; p < 0.01), but not lactate. At admission, venous to arterial CO2 difference was also moderately correlated with central venous oxygen saturation (R = -0.40; p < 0.01) and arteriovenous oxygen saturation difference (R = 0.55; p < 0.01), but not lactate. Thirty-four of 139 neonates (24.5%) had poor outcome. Median admission venous to arterial CO2 difference was 5.9 mm Hg (3.8-9.2 mm Hg). Patients with poor outcome had median admission venous to arterial CO2 difference 8.3 (5.6-14.9) versus 5.4 mm Hg (3.0-8.4 mm Hg) in those without poor outcome. Venous to arterial CO2 difference (area under the curve = 0.69; p < 0.01), serum lactate (area under the curve = 0.64; p = 0.02), and central venous oxygen saturation (area under the curve = 0.74; p < 0.01) were predictive of poor outcome. After controlling for covariates, admission venous to arterial CO2 difference remained significantly associated with poor outcome (odds ratio, 1.3; 95% CI, 1.1-1.45), including independent association with mortality (odds ratio, 1.2; 95% CI, 1.07-1.31). CONCLUSIONS: Venous to arterial CO2 difference is correlated with important surrogates of cardiac output, and is associated with poor outcome and mortality related to low cardiac output syndrome after cardiac surgery in infants. Prospective validation of these findings, including confirmation that venous to arterial CO2 difference can identify low cardiac output syndrome in real time, is warranted.

An Elevated Low Cardiac Output Syndrome Score Is Associated With Morbidity in Infants After Congenital Heart Surgery.

OBJECTIVES: To evaluate an empirically derived Low Cardiac Output Syndrome Score as a clinical assessment tool for the presence and severity of Low Cardiac Output Syndrome and to examine its association with clinical outcomes in infants who underwent surgical repair or palliation of congenital heart defects. DESIGN: Prospective observational cohort study. SETTING: Cardiac ICU at Seattle Children's Hospital. PATIENTS: Infants undergoing surgical repair or palliation of congenital heart defects. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Clinical and laboratory data were recorded hourly for the first 24 hours after surgery. A Low Cardiac Output Syndrome Score was calculated by assigning one point for each of the following: tachycardia, oliguria, toe temperature less than 30°C, need for volume administration in excess of 30 mL/kg/d, decreased near infrared spectrometry measurements, hyperlactatemia, and need for vasoactive/inotropes in excess of milrinone at 0.5 µg/kg/min. A cumulative Low Cardiac Output Syndrome Score was determined by summation of Low Cardiac Output Syndrome Score on arrival to cardiac ICU, and 8, 12, and 24 hours postoperatively. Scores were analyzed for association with composite morbidity (prolonged mechanical ventilation, new infection, cardiopulmonary arrest, neurologic event, renal dysfunction, necrotizing enterocolitis, and extracorporeal life support) and resource utilization. Fifty-four patients were included. Overall composite morbidity was 33.3%. Median peak Low Cardiac Output Syndrome Score and cumulative Low Cardiac Output Syndrome Score were higher in patients with composite morbidity (3 [2-5] vs 2 [1-3]; p = 0.003 and 8 [5-10] vs 2.5 [1-5]; p < 0.001)]. Area under the receiver operating characteristic curve for cumulative Low Cardiac Output Syndrome Score versus composite morbidity was 0.83, optimal cutoff of greater than 6. Patients with cumulative Low Cardiac Output Syndrome Score greater than or equal to 7 had higher morbidity, longer duration of mechanical ventilation, cardiac ICU, and hospital length of stay (all p ≤ 0.001). After adjusting for other relevant variables, peak Low Cardiac Output Syndrome Score and cumulative Low Cardiac Output Syndrome Score were independently associated with composite morbidity (odds ratio, 2.57; 95% CI, 1.12-5.9 and odds ratio, 1.35; 95% CI, 1.09-1.67, respectively). CONCLUSION: Higher peak Low Cardiac Output Syndrome Score and cumulative Low Cardiac Output Syndrome Score were associated with increased morbidity and resource utilization among infants following surgery for congenital heart defects and might be a useful tools in future cardiac intensive care research. Independent validation is required.

Identification of prognostic markers in transthyretin and AL cardiac amyloidosis.

BACKGROUND: The prognosis of amyloidosis is known to depend heavily on cardiac function and may be improved by identifying patients at highest risk for adverse cardiac events. AIMS: Identify predictors of mortality in patients with cardiac light-chain amyloidosis (AL), hereditary transthyretin amyloidosis (m-TTR), or wild-type transthyretin amyloidosis (WT-TTR) to prompt physician to refer these patients to dedicated centers. METHODS AND RESULTS: Observational study. About 266 patients referred for suspected cardiac amyloidosis (CA) in two French university centers were included. About 198 patients had CA (AL = 118, m-TTR = 57, and WT-TTR = 23). Their median (25th-75th percentile) age, NT-proBNP left ventricular ejection fraction were, respectively, 68 years (59-76), 2339 pg mL-1 (424-5974), and 60% (48-66). About 31% were in NYHA class III-IV. Interventricular septal thickness was greater in the m-TTR and WT-TTR groups than in the AL group (p < 0.0001). Median follow-up in survivor was 26 months (15-44) and 87 (44%) patients died. By multivariate analysis, independent predictors of mortality for AL amyloidosis were the following: age, cardiac output and NT-proBNP; for TTR amyloidosis was: NT-proBNP. When all amyloidosis were combined NT-proBNP, low cardiac output and pericardial effusion were independently associated with mortality. CONCLUSION: NT-proBNP is a strong prognosticator in the three types of cardiac amyloidosis. High NT-proBNP, low cardiac output, and pericardial effusion at the time of screening should prompt physician to refer the patients to amyloidosis referral center.