How to assess prognosis after cardiac arrest and therapeutic hypothermia.

The prognosis of patients who are admitted in a comatose state following successful resuscitation after cardiac arrest remains uncertain. Although the introduction of therapeutic hypothermia (TH) and improvements in post-resuscitation care have significantly increased the number of patients who are discharged home with minimal brain damage, short-term assessment of neurological outcome remains a challenge. The need for early and accurate prognostic predictors is crucial, especially since sedation and TH may alter the neurological examination and delay the recovery of motor response for several days. The development of additional tools, including electrophysiological examinations (electroencephalography and somatosensory evoked potentials), neuroimaging and chemical biomarkers, may help to evaluate the extent of brain injury in these patients. Given the extensive literature existing on this topic and the confounding effects of TH on the strength of these tools in outcome prognostication after cardiac arrest, the aim of this narrative review is to provide a practical approach to post-anoxic brain injury when TH is used. We also discuss when and how these tools could be combined with the neurological examination in a multimodal approach to improve outcome prediction in this population.

Peroxynitrite induces HMGB1 release by cardiac cells in vitro and HMGB1 upregulation in the infarcted myocardium in vivo.

AIMS: High-mobility group box 1 (HMGB1) is a nuclear protein actively secreted by immune cells and passively released by necrotic cells that initiates pro-inflammatory signalling through binding to the receptor for advance glycation end-products. HMGB1 has been established as a key inflammatory mediator during myocardial infarction, but the proximal mechanisms responsible for myocardial HMGB1 expression and release in this setting remain unclear. Here, we investigated the possible involvement of peroxynitrite, a potent cytotoxic oxidant formed during myocardial infarction, on these processes. METHODS AND RESULTS: The ability of peroxynitrite to induce necrosis and HMGB1 release in vitro was evaluated in H9c2 cardiomyoblasts and in primary murine cardiac cells (myocytes and non-myocytes). In vivo, myocardial HMGB1 expression and nitrotyrosine content (a marker of peroxynitrite generation) were determined following myocardial ischaemia and reperfusion in rats, whereas peroxynitrite formation was inhibited by two different peroxynitrite decomposition catalysts: 5,10,15,20-tetrakis(4-sulphonatophenyl) porphyrinato iron (III) (FeTPPS) or Mn(III)-tetrakis(4-benzoic acid) porphyrin chloride (MnTBAP). In all types of cells studied, peroxynitrite (100 μM) elicited significant necrosis, the loss of intracellular HMGB1, and its passive release into the medium. In vivo, myocardial ischaemia-reperfusion induced significant myocardial necrosis, cardiac nitrotyrosine formation, and marked overexpression of myocardial HMGB1. FeTPPS reduced nitrotyrosine, decreased infarct size, and suppressed HMGB1 overexpression, an effect that was similarly obtained with MnTBAP. CONCLUSION: These findings indicate that peroxynitrite represents a key mediator of HMGB1 overexpression and release by cardiac cells and provide a novel mechanism linking myocardial oxidative/nitrosative stress with post-infarction myocardial inflammation.

Réadaptation cardiovasculaire, un- bien sous-utilisé [Cardiac rehabilitation, a proven intervention underutilized in the French-speaking part of Switzerland].

Cardiac rehabilitation is associated with a reduced risk of recurrence and mortality after an acute coronary syndrome. Cardiac rehabilitation is a multidisciplinary approach which starts during the acute hospital phase, then followed by a four to six weeks home-based or stationary program, in order to maintain long-term lifestyle changes. Despite the important health benefits of cardiac rehabilitation and its cost-effectiveness, only half of the patients in Europe will achieve a cardiovascular prevention program after an acute coronary syndrome. In the French part of Switzerland, one explanation for this low adherence might be the lack of both stationary and home-based program facilities.

Delay of extubation in neonates and children after cardiac surgery: impact of ventilator-associated pneumonia.

OBJECTIVE: This study was undertaken to determine the delay of extubation attributable to ventilator-associated pneumonia (VAP) in comparison to other complications and complexity of surgery after repair of congenital heart lesions in neonates and children. METHODS: Cohort study in a pediatric intensive care unit of a tertiary referral center. All patients who had cardiac operations during a 22-month period and who survived surgery were eligible (n = 272, median age 1.3 years). Primary outcome was time to successful extubation. Primary variable of interest was VAP Surgical procedures were classified according to complexity. Cox proportional hazards models were calculated to adjust for confounding. Potential confounders comprised other known risk factors for delayed extubation. RESULTS: Median time to extubation was 3 days. VAP occurred in 26 patients (9.6%). The rate of VAP was not associated with complexity of surgery (P = 0.22), or cardiopulmonary bypass (P = 0.23). The adjusted analysis revealed as further factors associated with delayed extubation: other respiratory complications (n = 28, chylothorax, airway stenosis, diaphragm paresis), prolonged inotropic support (n = 48, 17.6%), and the need for secondary surgery (n = 51, 18.8%; e.g., re-operation, secondary closure of thorax). Older age promoted early extubation. The median delay of extubation attributable to VAP was 3.7 days (hazards ratio HR = 0.29, 95% CI 0.18-0.49), exceeding the effect size of secondary surgery (HR = 0.48) and other respiratory complications (HR = 0.50). CONCLUSION: VAP accounts for a major delay of extubation in pediatric cardiac surgery.

Cardiac function assessed by transesophageal echocardiography during pectus excavatum repair.

BACKGROUND: We assessed end-diastolic right ventricular (RV) dimensions and left ventricular (LV) ejection fraction by use of intraoperative transesophageal echocardiography before and after surgical correction of pectus excavatum in adults. METHODS: A prospective study was conducted including 17 patients undergoing surgical correction of pectus excavatum according to the technique of Ravitch-Shamberger between 1999 and 2004. Intraoperative transesophageal echocardiography was performed under general anesthesia before and after surgery to assess end-diastolic RV dimensions and LV ejection fraction. The end-diastolic RV diameter and area were measured in four-chamber and RV inflow-outflow view, and the RV volume was calculated from these data. The LV was assessed by transgastric short-axis view, and its ejection fraction was calculated by use of the Teichholz formula. RESULTS: The end-diastolic RV diameter, area, and volume all significantly increased after surgery (mean values +/- SD, respectively: 2.4 +/- 0.8 cm versus 3.0 +/- 0.9 cm, p < 0.001; 12.5 +/- 5.2 cm(2) versus 18.4 +/- 7.5 cm(2), p < 0.001; and 21.7 +/- 11.7 mL versus 40.8 +/- 23 mL, p < 0.001). The LV ejection fraction also significantly increased after surgery (58.4% +/- 15% versus 66.2% +/- 6%, p < 0.001). CONCLUSIONS: Surgical correction of pectus excavatum according to Ravitch-Shamberger technique results in a significant increase in end-diastolic RV dimensions and a significantly increased LV ejection fraction.

FGF-2 controls the differentiation of resident cardiac precursors into functional cardiomyocytes.

Recent evidence suggests that the heart possesses a greater regeneration capacity than previously thought. In the present study, we isolated undifferentiated precursors from the cardiac nonmyocyte cell population of neonatal hearts, expanded them in culture, and induced them to differentiate into functional cardiomyocytes. These cardiac precursors appear to express stem cell antigen-1 and demonstrate characteristics of multipotent precursors of mesodermal origin. Following infusion into normal recipients, these cells home to the heart and participate in physiological and pathophysiological cardiac remodeling. Cardiogenic differentiation in vitro and in vivo depends on FGF-2. Interestingly, this factor does not control the number of precursors but regulates the differentiation process. These findings suggest that, besides its angiogenic actions, FGF-2 could be used in vivo to facilitate the mobilization and differentiation of resident cardiac precursors in the treatment of cardiac diseases.

Brain natriuretic peptide is able to stimulate cardiac progenitor cell proliferation and differentiation in murine hearts after birth.

Brain natriuretic peptide (BNP) contributes to heart formation during embryogenesis. After birth, despite a high number of studies aimed at understanding by which mechanism(s) BNP reduces myocardial ischemic injury in animal models, the actual role of this peptide in the heart remains elusive. In this study, we asked whether BNP treatment could modulate the proliferation of endogenous cardiac progenitor cells (CPCs) and/or their differentiation into cardiomyocytes. CPCs expressed the NPR-A and NPR-B receptors in neonatal and adult hearts, suggesting their ability to respond to BNP stimulation. BNP injection into neonatal and adult unmanipulated mice increased the number of newly formed cardiomyocytes (neonatal: +23 %, p = 0.009 and adult: +68 %, p = 0.0005) and the number of proliferating CPCs (neonatal: +142 %, p = 0.002 and adult: +134 %, p = 0.04). In vitro, BNP stimulated CPC proliferation via NPR-A and CPC differentiation into cardiomyocytes via NPR-B. Finally, as BNP might be used as a therapeutic agent, we injected BNP into mice undergoing myocardial infarction. In pathological conditions, BNP treatment was cardioprotective by increasing heart contractility and reducing cardiac remodelling. At the cellular level, BNP stimulates CPC proliferation in the non-infarcted area of the infarcted hearts. In the infarcted area, BNP modulates the fate of the endogenous CPCs but also of the infiltrating CD45(+) cells. These results support for the first time a key role for BNP in controlling the progenitor cell proliferation and differentiation after birth. The administration of BNP might, therefore, be a useful component of therapeutic approaches aimed at inducing heart regeneration.

Why bystanders decline telephone cardiac resuscitation advice.

OBJECTIVES: The aim of this study was to evaluate the rate and reason for refusal of telephone-based cardiopulmonary resuscitation (CPR) instruction by bystanders after the implementation of the dispatch center's systematic telephone CPR protocol. METHODS: Over a 15-month period the authors prospectively collected all case records from the emergency medical services (EMS) dispatch center when CPR had been proposed to the bystander calling in and recorded the reason for declining or not performing that the bystander spontaneously mentioned. All pediatric and adult traumatic and nontraumatic cases were included. Situations when resuscitation had been spontaneously initiated by bystanders were excluded. RESULTS: During the study period, dispatchers proposed CPR on 264 occasions: 232 adult nontraumatic cases, 17 adult traumatic cases, and 15 pediatric (traumatic and nontraumatic) cases. The proposal was accepted in 163 cases (61.7%, 95% confidence interval [CI] = 54.6% to 66.5%), and CPR was eventually performed in 134 cases (51%, 95% CI = 43.2% to 55.3%). In 35 of the cases where resuscitation was not carried out, the condition of the patient or conditions at the scene made this decision medically appropriate. Of the remaining 95 cases, 55 were due to physical limitations of the caller, and 33 were due to emotional distress. CONCLUSIONS: The telephone CPR acceptance rate of 62% in this study is comparable to those of other similar studies. Because bystanders' physical condition is one of the keys to success, the rate may not improve as the population ages.

Paediatric cardiac CT examinations: impact of the iterative reconstruction method ASIR on image quality--preliminary findings.

BACKGROUND: Radiation dose exposure is of particular concern in children due to the possible harmful effects of ionizing radiation. The adaptive statistical iterative reconstruction (ASIR) method is a promising new technique that reduces image noise and produces better overall image quality compared with routine-dose contrast-enhanced methods. OBJECTIVE: To assess the benefits of ASIR on the diagnostic image quality in paediatric cardiac CT examinations. MATERIALS AND METHODS: Four paediatric radiologists based at two major hospitals evaluated ten low-dose paediatric cardiac examinations (80 kVp, CTDI(vol) 4.8-7.9 mGy, DLP 37.1-178.9 mGy·cm). The average age of the cohort studied was 2.6 years (range 1 day to 7 years). Acquisitions were performed on a 64-MDCT scanner. All images were reconstructed at various ASIR percentages (0-100%). For each examination, radiologists scored 19 anatomical structures using the relative visual grading analysis method. To estimate the potential for dose reduction, acquisitions were also performed on a Catphan phantom and a paediatric phantom. RESULTS: The best image quality for all clinical images was obtained with 20% and 40% ASIR (p < 0.001) whereas with ASIR above 50%, image quality significantly decreased (p < 0.001). With 100% ASIR, a strong noise-free appearance of the structures reduced image conspicuity. A potential for dose reduction of about 36% is predicted for a 2- to 3-year-old child when using 40% ASIR rather than the standard filtered back-projection method. CONCLUSION: Reconstruction including 20% to 40% ASIR slightly improved the conspicuity of various paediatric cardiac structures in newborns and children with respect to conventional reconstruction (filtered back-projection) alone.

The alpha(1A/C)- and alpha(1B)-adrenergic receptors are required for physiological cardiac hypertrophy in the double-knockout mouse.

Catecholamines and alpha(1)-adrenergic receptors (alpha(1)-ARs) cause cardiac hypertrophy in cultured myocytes and transgenic mice, but heart size is normal in single KOs of the main alpha(1)-AR subtypes, alpha(1A/C) and alpha(1B). Here we tested whether alpha(1)-ARs are required for developmental cardiac hypertrophy by generating alpha(1A/C) and alpha(1B) double KO (ABKO) mice, which had no cardiac alpha(1)-AR binding. In male ABKO mice, heart growth after weaning was 40% less than in WT, and the smaller heart was due to smaller myocytes. Body and other organ weights were unchanged, indicating a specific effect on the heart. Blood pressure in ABKO mice was the same as in WT, showing that the smaller heart was not due to decreased load. Contractile function was normal by echocardiography in awake mice, but the smaller heart and a slower heart rate reduced cardiac output. alpha(1)-AR stimulation did not activate extracellular signal-regulated kinase (Erk) and downstream kinases in ABKO myocytes, and basal Erk activity was lower in the intact ABKO heart. In female ABKO mice, heart size was normal, even after ovariectomy. Male ABKO mice had reduced exercise capacity and increased mortality with pressure overload. Thus, alpha(1)-ARs in male mice are required for the physiological hypertrophy of normal postnatal cardiac development and for an adaptive response to cardiac stress.

Myocardial flow reserve by Rb-82 cardiac PET improves the selection of patients eligible for invasive coronary angiography

Aim: We asked whether myocardial flow reserve (MFR) by Rb-82 cardiac PET improve the selection of patients eligible for invasive coronary angiography (ICA). Material and Methods: We enrolled 26 consecutive patients with suspected or known coronary artery disease who performed dynamic Rb-82 PET/CT and (ICA) within 60 days; 4 patients who underwent revascularization or had any cardiovascular events between PET and ICA were excluded. Myocardial blood flow at rest (rMBF), at stress with adenosine (sMBF) and myocardial flow reserve (MFR=sMBF/rMBF) were estimated using the 1-compartment Lortie model (FlowQuant) for each coronary arteries territories. Stenosis severity was assessed using computer-based automated edge detection (QCA). MFR was divided in 3 groups: G1:MFR<1.5, G2:1.5≤MFR<2 and G3:2≤MFR. Stenosis severity was graded as non-significant (<50% or FFR ≥0.8), intermediate (50%≤stenosis<70%) and severe (≥70%). Correlation between MFR and percentage of stenosis were assessed using a non-parametric Spearman test. Results: In G1 (44 vessels), 17 vessels (39%) had a severe stenosis, 11 (25%) an intermediate one, and 16 (36%) no significant stenosis. In G2 (13 vessels), 2 (15%) vessels presented a severe stenosis, 7 (54%) an intermediate one, and 4 (31%) no significant stenosis. In G3 (9 vessels), 0 vessel presented a severe stenosis, 1 (11%) an intermediate one, and 8 (89%) no significant stenosis. Of note, among 11 patients with 3-vessel low MFR<1.5 (G1), 9/11 (82%) had at least one severe stenosis and 2/11 (18%) had at least one intermediate stenosis. There was a significant inverse correlation between stenosis severity and MFR among all 66 territories analyzed (rho= -0.38, p=0.002). Conclusion: Patients with MFR>2 could avoid ICA. Low MFR (G1, G2) on a vessel-based analysis seems to be a poor predictor of severe stenosis severity. Patients with 3-vessel low MFR would benefit from ICA as they are likely to present a significant stenosis in at least one vessel.

Cardiac Function Assessed by Transesophageal Echocardiography During Pectus Excavatum Repair

Background. We assessed end-diastolic right ventricular (RV) dimensions and left ventricular (LV) ejection fraction by use of intraoperative transesophageal echocardiography before and after surgical correction of pectus excavatum in adults. Methods. A prospective study was conducted including 17 patients undergoing surgical correction of pectus excavatum according to the technique of Ravitch-Shamberger between 1999 and 2004. Intraoperative transesophageal echocardiography was performed under general anesthesia before and after surgery to assess end-diastolic RV dimensions and LV ejection fraction. The end-diastolic RV diameter and area were measured in four-chamber and RV inflow-outflow view, and the RV volume was calculated from these data. The LV was assessed by transgastric short-axis view, and its ejection fraction was calculated by use of the Teichholz formula. Results. The end-diastolic RV diameter, area, and volume all significantly increased after surgery (mean values +/- SD, respectively: 2.4 +/- 0.8 cm versus 3.0 +/- 0.9 cm, p < 0.001; 12.5 +/- 5.2 cm(2) versus 18.4 +/- 7.5 cm(2), p < 0.001; and 21.7 +/- 11.7 mL versus 40.8 +/- 23 mL, p < 0.001). The LV ejection fraction also significantly increased after surgery (58.4% +/- 15% versus 66.2% +/- 6%, p < 0.001). Conclusions. Surgical correction of pectus excavatum according to Ravitch-Shamberger technique results in a significant increase in end-diastolic RV dimensions and a significantly increased LV ejection fraction. (Ann Thorac Surg 2010; 89: 240-4) (C) 2010 by The Society of Thoracic Surgeons

Advantages of a cohort study on cardiac arrest conducted by nurses

AbstractOBJECTIVEIdentifying factors associated to survival after cardiac arrest.METHODAn experience report of a cohort study conducted in a university hospital, with a consecutive sample comprised of 285 patients. Data were collected for a year by trained nurses. The training strategy was conducted through an expository dialogue lecture. Collection monitoring was carried out by nurses via telephone calls, visits to the emergency room and by medical record searches. The neurological status of survivors was evaluated at discharge, after six months and one year.RESULTSOf the 285 patients, 16 survived until hospital discharge, and 13 remained alive after one year, making possible to identify factors associated with survival. There were no losses in the process.CONCLUSIONCohort studies help identify risks and disease outcomes. Considering cardiac arrest, they can subsidize public policies, encourage future studies and training programs for CPR, thereby improving the prognosis of patients.

Predictors of red blood cell transfusion after cardiac surgery: a prospective cohort study

Abstract OBJECTIVE To identify predictors of red blood cell transfusion (RBCT) after cardiac surgery. METHOD A prospective cohort study performed with 323 adults after cardiac surgery, from April to December of 2013. A data collection instrument was constructed by the researchers containing factors associated with excessive bleeding after cardiac surgery, as found in the literature, for investigation in the immediate postoperative period. The relationship between risk factors and the outcome was assessed by univariate analysis and logistic regression. RESULTS The factors associated with RBCT in the immediate postoperative period included lower height and weight, decreased platelet count, lower hemoglobin level, higher prevalence of platelet count <150x10 3/mm3, lower volume of protamine, longer duration of anesthesia, higher prevalence of intraoperative RBCT, lower body temperature, higher heart rate and higher positive end-expiratory pressure. The independent predictor was weight <66.5Kg. CONCLUSION Factors associated with RBCT in the immediate postoperative period of cardiac surgery were found. The independent predictor was weight.