Pathology-related troponin I release and clinical outcome after pediatric open heart surgery

Postoperative Troponin Levels in Children Undergoing Open Heart Surgery With and Without Coronary Intervention

We aimed to characterize the ranges, temporal trends, influencing factors, and prognostic significance of postoperative troponin levels after congenital heart surgery. This single-center retrospective study included patients from 2006 to 2021 who had ≥ 1 postoperative troponin-T measurement collected within 96 h of congenital heart surgery (CHS). Patients were grouped as Anomalous Aortic Origin of the Coronary Artery-"AAOCA repair," or congenital heart surgery with "Other Coronary Interventions" other than AAOCA repair, or "No Coronary Intervention." In each group, information on concomitant surgery requiring one or more of the following-atriotomy, ventriculotomy, right ventricular muscle bundle resection, and/or septal myectomy-was collected. Clinical correlates of troponin values were analyzed in three postoperative windows: < 8, 8-24, and 24-48 h. The highest median [range] troponin levels (ng/mL) for the samples were 0.34 [0.06, 1.32] at < 8 h for "AAOCA repair," 1.35 [0.14, 12.0] at < 8 h for those undergoing CHS with "Other Coronary Interventions," and 0.87 [0.06, 25.1] at 8-24 h for those undergoing CHS with "No Coronary Interventions." Atriotomy was associated with higher median troponin levels in the AAOCA group at < 8 h (0.40 [0.31, 0.77] vs. 0.29 [0.17, 0.54], P = 0.043) and in the Other Coronary Intervention group at 8-24 h (1.67 [1.04, 2.63] vs. 0.40 [0.19, 1.32], P = 0.002). Patients experiencing major postoperative complications (vs. those who did not) had higher troponin levels in the AAOCA group as early as 8-24 h (0.36 [0.24, 0.57] vs. 0.21 [0.14, 0.33], P = 0.03). Similar findings were noted in the Coronary Intervention (2.20 [1.34, 3.90] vs. 1.11 [0.51, 2.90], P = 0.028) and No Coronary Intervention (2.2 [1.49, 15.1] vs. 0.74 [0.40, 2.34], P = 0.027) groups but earlier at < 8 h. In the AAOCA group, 2/18 (11%) troponin outliers experienced cardiac arrest in comparison to 0/80 (0%) non-outliers (P = 0.032). In the Other Coronary Intervention group, troponin outliers had longer median times to ICU discharge (10 vs. 4 days) and hospital discharge (21 vs. 10 days) (both P < 0.001). Postoperative troponin levels depend on a multitude of factors and may have prognostic value in patients undergoing congenital heart surgery with coronary interventions.

Screening and evaluation of TBX20 and CITED2 mutations in children with congenital cardiac septal defects: Correlation with cardiac troponin T and caspase-3

Congenital cardiac septal defect (CCSD) is the main type of congenital heart disease and owns a very high mortality rate among newborns. CCSD is controlled by specific transcription factors, including T-box transcription factor 20 (TBX20) and Cbp/P300 interacting transactivator with Glu/Asp rich carboxy-terminal domain 2 (CITED2) which are key molecular actors in heart development. Here, we screened for mutations in TBX20 and CITED2 genes in Egyptian children with CCSD and assessed their association with CCSD susceptibility and with cardiac troponin T (cTnT) and the apoptotic marker caspase-3 as biochemical markers for CCSD. Thirty unrelated newborns and children affected with CCSD and 30 matched healthy controls with no personal history of cardiac diseases were recruited. Selection criteria were children (<18 years) with any age diagnosed with CCSD using ECHO. Mutational analysis and genotyping were done using PCR-Sanger DNA sequencing technique. Serum cTnT and caspase-3 were analyzed using ELISA. Sequencing analysis identified 2 TBX20 variants (c.766T>C and c.39T>C) in the CCSD and control groups and 2 CITED2 variants (c.12T>C and c.9C>T) in one CCSD patient, while were absent in controls. In silico analysis identified TBX20 c.766T>C (rs3999941) as a missense (F256L) pathogenic variant and the other three variants as synonymous and benign. Compared with controls, TBX20 c.766T>C TC genotype and minor C allele were candidate high-risk factors for CCSD. Besides, serum cTnT and caspase-3 were dramatically elevated in CCSD children compared to controls. TBX20 c.766T>C TC genotype was associated with high cTnT in CCSD children. Conclusively, we advocate TBX20 c.766T>C variant as a potential genetic marker for CCSD which might associate with high cTnT levels. CITED2 genetic variants might have rare incidence among Egyptian CCSD children. Serum cTnT and caspase-3 are useful markers for ascertaining CCSD in children. These data could be exploited in prenatal genetic counseling, pre-implantation genotyping, and therapy of CCSD.

End-diastolic forward flow in repaired tetralogy of Fallot: Mid-term outcomes from a single center

Background

Pulmonary arterial end-diastolic forward flow (EDFF) following repaired tetralogy of Fallot (rTOF) is recognized as right ventricular (RV) restrictive physiology, which is closely related to poor prognosis. This study sought to review mid-term experience and investigate the risk factors of EDFF in the rTOF patients.

Methods

From September 2016 to January 2019, 100 patients (age < 18 years old) who underwent complete tetralogy of Fallot (TOF) repair were enrolled and were divided into EDFF group (n = 52) and non-EDFF group (n = 48) based on the presence of postoperative EDFF. Elastic net analysis was performed for variable selection. Univariate and multivariate logistic analyses were used to analyze the correlation between risk factors and EDFF.

Results

End-diastolic forward flow group had lower systolic blood pressure (P = 0.037), diastolic blood pressure (P = 0.027), and higher vasoactive-inotrope score within 24 h after surgery (P = 0.022) than non-EDFF group. Transannular patch (TAP) was an independent predictor of postoperative EDFF [P = 0.029, OR: 2.585 (1.102∼6.061)]. Patients were followed up for a median of 2.6 years [interquartile range (IQR) 1.6] after the first TOF repair. During follow-up, the prevalence of the EDFF was lower in those with pulmonary valve (PV) reconstructions than that in those undergoing patch enlargement without PV reconstructions in the primary TOF repair (P < 0.001).

Conclusion

End-diastolic forward flow was associated with TAP. Patients with EDFF might have a transient hemodynamic instability in the early postoperative period. PV reconstructions in the TOF repair might reduce the incidence of EDFF in the mid-term follow-up.

Post-operative troponin levels and left ventricular function in patients with d-transposition of the great arteries following the arterial switch operation

The aim of this study was to assess the significance of post-operative troponin levels as a surrogate for left ventricular (LV) dysfunction measured by global longitudinal strain (GLS) in patients with dextro-transposition of the great arteries (d-TGA) who undergo an arterial switch operation (ASO), and to explore the LV GLS recovery in the mid-term follow-up period. Seventy-eight neonates were included, of whom 41 had troponin-I measurements and 37 had troponin-T measurements. The primary outcome of LV GLS was assessed and compared with healthy controls at the pre-operative stage and time of discharge, 3 months, 6 months and 12 months of age. Secondary outcomes included deaths or transplantations and other clinical markers such as length of hospital stay. D-TGA patients had worse LV GLS post-operatively compared to age-matched controls (p < 0.01) which improved by 12 months of age (p = 0.53). No association was found between changes in troponin-I or troponin-T levels and LV GLS at the time of discharge (r = 0.4, p = 0.64 and r = -0.5, p = 0.91, respectively). In addition, there were no deaths or transplantations in this cohort over a period of 12 months. LV GLS appears to worsen in the early post-operative period for d-TGA patients who undergo neonatal ASO but this recovers through the first post-operative year. Troponin levels have limited value in predicting early or midterm LV dysfunction and recovery.

Detection of Early Myocardial Injury in Children with Ventricular Septal Defect Using Cardiac Troponin I and Two-Dimensional Speckle Tracking Echocardiography

Children with ventricular septal defects (VSDs) are subjected to hemodynamic overload which causes myocardial injury and subsequent heart failure. Early stages of myocardial damage cannot be detected by conventional echocardiography. Two-dimensional speckle tracking echocardiography (2D-STE) and cardiac troponin I (cTnI) have been recently introduced as more accurate tools for early assessment of cardiovascular diseases. The purpose of this study is to evaluate the role of cardiac troponin I (cTnI) and 2D-STE in the early detection of VSD-induced myocardial injury. Thirty children with VSD (symptomatic and asymptomatic) and 30 controls were assessed serologically by measuring serum cTnI and by conventional echocardiography. STE was performed to measure the averaged global peak longitudinal systolic stain [G peak SL(AVG)]. Serum cTnI levels were significantly higher in patients when compared to controls (P < 0.05) and in the symptomatic group when compared to the asymptomatic group (P < 0.05). Serum cTn I level correlated positively with the left atrial (r = 0.37, P = 0.045) and left ventricular dimensions (r = 0.46, P = 0.01) and negatively with the G peak SL(AVG) (r = -0.39, P = 0.03). There were no statistically significant differences between patients and controls or between symptomatic and asymptomatic groups with regard to the G peak SL(AVG). The peak longitudinal systolic strain (measured by 2D-STE) is not affected despite the elevation of serum cTnI. Serum cTnI is a sensitive marker for early detection of myocardial injury in VSD patients even before the development of ventricular dilatation or dysfunction.

Myocardial protection and clinical outcomes in Tetralogy of Fallot patients undergoing intracardiac repair: a randomized study of two cardioplegic techniques

Background:

Myocardial protection in Tetralogy of Fallot patients undergoing intracardiac repair is suboptimal due to hypertrophied right ventricle. Hypertrophied myocardium is more susceptible to poor myocardial preservation because of inadequate capillary density as compared to the myocytes. There is a capillary to myocyte ratio mismatch. But del Nido Cardioplegia owing to its less viscosity is able to get more evenly distributed under hypothermic cardiopulmonary bypass as opposed to blood Cardioplegia. We hypothesized that the del Nido Cardioplegia technique, would be beneficial in myocardial protection because of its composition and method of delivery, leading into better early and late clinical outcomes in patients undergoing Tetralogy of Fallot repair as compared to blood cardioplegia reconstituted using St Thomas Cardioplegia solution. The objective of the study was to identify a better technique of myocardial preservation in Tetralogy of Fallot patient.

Methods:

In total, 56 Tetralogy of Fallot patients undergoing intracardiac repair under mild hypothermic cardiopulmonary bypass were randomly allocated to receive antegrade Cardioplegia with either standard blood Cardioplegia (Group I) or del Nido Cardioplegia (Group II). Preoperative as well as postoperative data including echocardiographic parameters for right ventricle functions, creatine kinase MB level, inotropic requirement, mechanical ventilation duration, intensive care unit stay and hospital mortality were evaluated.

Results:

Inotropic score in the first 24 hours postoperatively was significantly lower in Group II compared to Group I (13.4 ± 7.2 vs. 21.2 ± 9.6, p = 0.003). Creatine kinase MB level (ng/mL) was comparable between the groups. Echocardiographic parameters for right ventricle functions were also comparable between the groups during early as well as after 3 to 6 months postoperatively.

Conclusion:

Del Nido Cardioplegia is equally efficacious in providing myocardial protection during intracardiac repair under mild hypothermic cardiopulmonary bypass in Tetralogy of Fallot patients as compared to blood Cardioplegia solution with the added benefit of reducing inotropic requirement in first 24 hours postoperative period.

Postoperative Serum Troponin Trends in Infants Undergoing Cardiac Surgery

Troponin-I (TN-I) levels are elevated following pediatric cardiac surgery with speculation that particular patterns may have prognostic significance. There is lack of procedure-specific data regarding postoperative TN-I levels in infants undergoing cardiac surgery. We hypothesized that TN-I elevation varies with type of surgery and persistent elevation predicts poor prognosis. We prospectively measured serial TN-I levels (preoperatively, 4, 8, 12, 24, and 48 hours postoperatively) in 90 infants (age < 1 year) undergoing cardiac surgery: off cardiopulmonary bypass (CPB) (n = 15), on CPB (n = 43), and on CPB with ventricular incision (CPB with ventricular incision; n = 32). All patients had undetectable baseline TN-I levels. The area under the curve of TN-I levels over the 48-hour period was significantly different among the surgical groups (P < 0.002), and highest in patients with CPB with ventricular incision. Generally, TN-I levels peaked by 4 hours after surgery and returned to near-normal levels within 48 hours. A persistent TN-I rise beyond 8 hours after surgery was a strong predictor of postoperative hypoperfusion injury (defined as a composite endpoint of end-organ injury resulting from inadequate perfusion, odds ratio 21.5; P = 0.001) and mortality (30% in those with persistently high TN-I, compared with 3.5% in the remaining patients; P < 0.001), independent of patient age, anatomy and/or complexity of surgery, and level of postoperative support. Our data provide benchmark values for TN-I levels following cardiac surgery in infants. Extent of TN-I elevation correlates with type of surgery. Persistent TN-I elevation beyond 8 hours after surgery is strongly associated with postoperative hypoperfusion injury and mortality.

Consecutive Isoproterenol and Adenosine Treatment Confers Marked Protection against Reperfusion Injury in Adult but Not in Immature Heart: A Role for Glycogen

Consecutive treatment of adult rat heart with isoproterenol and adenosine (Iso/Aden), known to consecutively activate PKA/PKC signaling, is cardioprotective against ischemia and reperfusion (I/R). Whether this is cardioprotective in an immature heart is unknown. Langendorff-perfused hearts from adult and immature (60 and 14 days old) male Wistar rats were exposed to 30 min ischemia and 120 min reperfusion, with or without prior perfusion with 5 nM Iso for 3 min followed by 30 μM Aden for 5 min. Changes in hemodynamics (developed pressure and coronary flow) and cardiac injury (Lactate Dehydrogenase (LDH) release and infarct size) were measured. Additional hearts were used to measure glycogen content. Iso induced a similar inotropic response in both age groups. Treatment with Iso/Aden resulted in a significant reduction in time to the onset of ischemic contracture in both age groups whilst time to peak contracture was significantly shorter only in immature hearts. Upon reperfusion, the intervention reduced cardiac injury and functional impairment in adults with no protection of immature heart. Immature hearts have significantly less glycogen content compared to adult. This work shows that Iso/Aden perfusion confers protection in an adult heart but not in an immature heart. It is likely that metabolic differences including glycogen content contribute to this difference.

Arterial Switch Operation and Plasma Biomarkers: Analysis and Correlation with Early Postoperative Outcomes

The aims of our study were to describe plasma brain natriuretic peptide (BNP), Troponin I (TnI), and Cystatin C (Cys-C) concentration kinetics in the postoperative period after arterial switch operation in neonate, and to test the correlation between the plasma biomarkers and early clinical outcomes. We prospectively enrolled 29 neonates who underwent ASO. All patients received Custodiol cardioplegia. Blood samples were collected preoperatively (one day before) and in the ICU immediately after admission, and then 6, 12, 24, and 48 h after surgery. TnI peak (mean 17.23 ± 7.0 ng/mL) occurred between the arrival in the ICU and the 6th hour, then we had a constant decrease. TnI had a good correlation with the inotropic support time (r = 0.560, p = 0.0015) and ICU time (r = 0.407, p = 0.028), less than with ventilation and Hospital stay (r = 0.37, p = 0.0451 and r = 0.385, p = 0.0404). BNP peak (mean 4773.79 ± 2724.52 ng/L) was in the preoperative time with a constant decrease after the operation and it had no significant correlations with clinical outcomes. The CyS-C had the highest preoperative values, which decreased during the operating phase, and then constantly increased upon arrival to the ICU with a peak at 48 h (mean 1.76 ± 0.35 mg/L). CyS-C peak had a good correlation with a plasmatic creatinine peak (r = 0.579, p = 0.0009) but not with other clinical outcomes. Our study demonstrated significant correlations between the Tnl peak and early clinical outcomes in neonates undergoing arterial switch operation. Other plasma biomarkers such as the BNP and CyS-C had no direct correlation.

Does Postoperative Cardiac Troponin-I Have Any Prognostic Value in Predicting Midterm Mortality After Congenital Cardiac Surgery?

OBJECTIVES

This study evaluated the prognostic value of postoperative cardiac troponin-I (cTnI) in predicting all-cause mortality up to 3 months after normothermic congenital cardiac surgery.

DESIGN

Prospective observational study.

SETTING

University hospital.

PARTICIPANTS

All children ages 0 to 10 years.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

cTnI was measured after the induction of anesthesia but before the surgery, at the pediatric intensive care unit arrival, and at 4, 12, and 24 hours postoperatively. Follow-up was extended up to 6 months. Overall, 169 children were analyzed, of whom 165 were survivors and 4 were nonsurvivors. cTnI levels were significantly higher in nonsurvivors only at 24 hours (p = 0.047). Children undergoing surgery with cardiopulmonary bypass (CPB) had significantly higher cTnI concentrations compared with those without CPB (p<0.001). Logistic regression analysis was performed on the 146 children in the CPB group with the following predictive variables: CPB time, postoperative cTnI concentrations, the presence of a cyanotic malformation, and intramyocardial incision. None of the variables predicted mortality. Postoperative cTnI concentrations did not predict 6 months׳ mortality. Only cTnI at 24 hours predicted the length of stay in the pediatric intensive care unit.

CONCLUSIONS

This study did not find that postoperative cTnI concentration predicted midterm mortality after normothermic congenital heart surgery. (ClinicalTrials.gov identifier: NCT01616394).

Cardiac troponin I after cardiopulmonary bypass in infants in comparison with older children

OBJECTIVE

At the present time, there is a trend towards performing open heart surgery at a younger age. Myocardium of infants has been thought to be more vulnerable to cardiopulmonary bypass in comparison with adults. For this study, we evaluated the degree of myocardial injury by measurement of cardiac troponin levels in infants in comparison with older children for similar surgeries.

METHODS

Serum was collected before bypass, after bypass, and daily after surgery and serum cardiac troponin I level (micrograms per litre). The demographic data, cardiac diagnoses, types of surgery performed, and peri-operative parameters were collected.

RESULTS

Of the 21 children enrolled consecutively, five were infants. Among the 21 patients, four patients had post-operative peak troponin values greater than 100 (three were infants) and all four patients survived and had normal left ventricular systolic function upon discharge echocardiogram. The five infants had peak troponin levels of 222.3, 202, 129, 26.7, and 82.3. The post-operative peak troponin levels were significantly higher in infants (mean 132.5 with a standard deviation of 81.6) than in the older children (mean 40.3 with a standard deviation of 33.4), although there was no significant difference in bypass time, bypass temperature, cross-clamp time, or the length of stay in the intensive care unit between the two age groups.

CONCLUSIONS

Higher troponin release is seen in infants in comparison with older children after bypass for similar surgeries. A troponin level greater than 100 after bypass does not necessarily predict death or a severe cardiovascular event in the very young.

Correlation Between Pediatric Open Heart Surgery Outcomes and Arterial-mixed Venous Oxygen Saturation Differences

INTRODUCTION

Low Cardiac Output Syndrome (LCOS) contributes to postoperative morbidity and mortality. This article tries to find a predictive factor to interpret outcome after cardiac operation.

METHODS

In a cross-sectional study, 100 children with congenital heart disease undergoing cardiovascular surgery with cardiopulmonary bypass (CPB) without significant left-to-right shunt were selected. Arterial and central venous oxygen saturation values were measured via blood samples simultaneously obtained in 6-hr intervals for a total of 24-hr during postoperative period at hours 0, 6, 12, 18, and 24. Postoperative ventilation support (intubation period) and cardiovascular support were also obtained from the hospital records. Statistical analysis was later performed comparing the arterial-mixed venous oxygen saturation differences and durations of required ventilatory and cardiovascular support, both for the complicated and non-complicated patient groups. The data was processed with correlation Pearson and Mann-Whitney U tests in SPSS 15 software, P less than 0.05 was significant.

RESULTS

Mortality following cardiac operation is 6% and complications may happen in 45% of the cases. The highest Arterial-mixed venous oxygen saturation difference occurred immediately post operation (up to 57%). These measures were high up to 18 hours in complicated and non-complicated groups (36% vs. 31% ; P< 0.05). This factor cannot predict prolongation of intubation period in patients (P > 0.05).

CONCLUSION

Arterial-mixed venous oxygen saturation difference may be high as much as 57% or as low as 23%.These different measures, being higher up to 18 hours in complicated to non-complicated groups after 18 hours, can be related to tissue ischemia during surgery and cannot be discriminative.

Cardioprotective effect of transcutaneous electric acupoint stimulation in the pediatric cardiac patients: a randomized controlled clinical trial

BACKGROUND

Acupuncture pretreatment exerts neuroprotective and cardioprotective effects in animal models and in adult patients underwent cardiac surgery; however, data in pediatric patient are unavailable.

OBJECTIVE/AIM

To investigate the effects of transcutaneous electric acupoint stimulation (TEAS) on acute myocardial injury from pediatric open-heart surgery.

METHODS

Children, aged 2-12 years, with congenital heart defects scheduled for surgical repair were enrolled. They were randomized to TEAS (administrated at bilateral P6 acupoint for 30 min after basal anesthesia) and control (an electrode was placed on the arm without stimulus) groups. The primary end point was serum cardiac troponin I (cTnI) over 24 h after aortic unclamping. Furthermore, clinical outcome and serum cytokine and C-reactive protein concentrations were evaluated.

RESULTS

Seventy eligible children were analyzed, 36 in controls and 34 in TEAS group. Compared with controls, the mean cTnI levels were significantly lower in TEAS group at 8 h (P = 0.043) and 24 h (P = 0.046) after aortic unclamping. The duration of ventilation (P = 0.004) and length of ICU stay (P = 0.032) was significantly longer in controls than in TEAS group. There was a significant difference in the release of C-reactive protein at 8 h (P = 0.039) between two groups, whereas the values for cytokines were not significant.

CONCLUSION

Transcutaneous electric acupoint stimulation on the bilateral P6 acupoint is effective for attenuation myocardial injury in children undergoing cardiac surgery. The beneficial effects may be partially associated with reduction in cTnI and C-reactive protein level in the early postoperative period.

Early elevation of cardiac troponin I is predictive of short-term outcome in neonates and infants with coronary anomalies or reduced ventricular mass undergoing cardiac surgery

OBJECTIVE

The present study aimed to assess the usefulness of routine monitoring of cardiac troponin I concentrations within 24 hours of surgery (cTn-I<24h) in neonates and infants undergoing cardiac surgery.

METHODS

The added predictive ability of a high peak cTn-I<24h (within the upper quintile per procedure) for a composite outcome, including 30-day mortality and severe morbidity, was assessed retrospectively. The predicted risk for the composite outcome was estimated from a logistic regression model including preoperative and intraoperative variables. Adding a high peak cTn-I<24h to the risk model resulted in reclassification of the predicted risk. It also allowed quantification of the improvement in reclassification and discrimination by the difference between c-indexes, the Net Reclassification and the Integrated Discrimination Indexes (NRI and IDI).

RESULTS

Overall, 1023 consecutive patients were included. Adding a high peak cTn-I<24h to the model resulted in no improvement in reclassification or discrimination in the overall population (difference between c-indexes: 0.011 [-0.004 to 0.029], NRI = 0.06, P = .22, IDI = 0.02, P = .06), except in a subgroup of patients undergoing the arterial switch operation with or without ventricular septal defect closure and/or aortic arc repair, anomalous origin of the left coronary artery from the pulmonary artery repair, truncus arteriosus repair, Norwood procedure, and Sano modification, in whom NRI = 0.23 (P = .005) and IDI = 0.05 (P < .001).

CONCLUSIONS

Patients with coronary anomalies and patients with reduced ventricular mass should benefit from the routine monitoring of cTn-I concentrations after surgery for congenital cardiac disease.

Effect of remote ischaemic preconditioning on ischaemic-reperfusion injury in pulmonary hypertensive infants receiving ventricular septal defect repair

BACKGROUND

Remote ischaemic preconditioning (RIPC) can reduce ischaemic-reperfusion injury in distant organs. The myocardial and pulmonary protective effect of RIPC in infants with pulmonary hypertension remains unclear. We conducted a randomized controlled trial to evaluate the effect of RIPC in infants receiving ventricular septal defect (VSD) repair.

METHODS

We studied 55 infants with pulmonary hypertension undergoing VSD repair (RIPC group, n=27; control group, n=28). RIPC consisted of four 5 min cycles of lower limb ischaemia and reperfusion. Serum troponin I (TnI) concentrations were measured after induction of anaesthesia and at 1, 6, 12, and 24 h after surgery. Other clinical data such as inotropic score, lung compliance, alveolar-arterial oxygen gradient, oxygen index, mechanical ventilation time, and length of intensive care unit stay were also recorded at each interval.

RESULTS

No differences in patient or surgical characteristics were observed between the two groups. There were no significant differences in postoperative TnI levels according to time (P=0.35) or the total amount of TnI release, expressed as the area under the curve over the 24 h after surgery [RIPC vs control: 207.6 (134.0) vs 274.6 (263.7) h ng ml(-1), P=0.24]. All other clinical data were also comparable.

CONCLUSIONS

RIPC does not reduce the postoperative TnI release after VSD repair in infants with pulmonary hypertension. Additionally, it is difficult to find significant clinical benefits of RIPC in this population. The effect of RIPC varies according to clinical situation and patient condition.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT01313832.

The myocardial protective effects of adenosine pretreatment in children undergoing cardiac surgery: a randomized controlled clinical trial

OBJECTIVE

Adenosine pretreatment reduces injury caused by ischemia-reperfusion. To investigate the hypothesis that adenosine pretreatment would modulate injury induced by cardiopulmonary bypass (CPB) and myocardial ischemia/reperfusion, we conducted a randomized controlled trial on the effects of adenosine pretreatment in children undergoing surgery to repair congenital heart defects.

METHODS

Children undergoing surgery to repair congenital heart defects were randomized to adenosine pretreatment or control treatment. Adenosine pretreatment was performed by infusing a total of 2.45 mg kg⁻¹ of adenosine over 10 min. Serum troponin I was measured pre- and postoperatively. Multiple clinical parameters, including postoperative use of inotropic medicine and duration in the intensive care unit (ICU), were recorded.

RESULTS

A total of 82 patients were enrolled in the study. There were 42 control patients and 40 patients in the adenosine pretreatment group. The mean age and weight of the two groups were not significantly different, nor were cardiopulmonary bypass and cross-clamp times. There were no deaths and severe complications in both groups. The adenosine pretreatment protocol caused significant hypotension but had no significant effect on heart rate. One patient had severe tachycardia shortly after the adenosine pretreatment protocol was completed, and adenosine infusion was continued until CPB was started. Postoperative levels of serum troponin I were greater in the control patients than in the adenosine pretreatment group, indicating that the control group suffered greater myocardial injury. Control group patients required more postoperative inotropic agents than those in the adenosine pretreatment group at 0, 1, and 3 h, indicating that the adenosine pretreatment group had a better cardiac function. The adenosine pretreatment group also required significantly less time in the ICU than the control group (3.2 ± 1.2 days vs 3.9 ± 1.2 days, p = 0.013).

CONCLUSIONS

This study demonstrates that adenosine pretreatment is protective of the myocardium during open-heart surgery in pediatric patients.

Genetic variants in mitochondrial tRNA genes are associated with essential hypertension in a Chinese Han population

BACKGROUND

Of multiple factors contributing to essential hypertension, mitochondrial variants exhibited the trends for serving as molecular and genetic markers for the disease in last five years. However, previous studies focused on African-American or Caucasian pedigrees, knowledge of mitochondrial tRNA genes and population-based Chinese hypertensives were limited.

METHODS

We performed sequence analysis in tRNA genes, hot spots for cardiovascular diseases, in 270 Chinese Han essential hypertensives and 270 controls. Lymphoblastoid cell lines were immortalized by transformation with the Epstein-Barr virus. Rates of oxygen consumption in intact cells were determined with a YSI 5300 oxygraph (Yellow Springs Instruments) on samples, harboring variants in tRNA genes.

RESULTS

There were 26 variants in tRNA genes that were found in hypertensives and these variants were not in controls. Functional analysis found that these variants may lead to deficiencies in tRNA 3' end metabolism and/or impairment of critical subunits of the respiratory chain. Most importantly, the oxygen consumption rate in cells harboring variants T4454C (P=0.0010) and A4263G (P=0.0001) decreased as compared to the average level of control cell lines.

CONCLUSIONS

Variants located in mitochondrial tRNA genes may have biologic plausibility to implicate in the pathogenesis of Chinese essential hypertension.

Cardiac Troponin T Levels for Risk Stratification in Pediatric Open Heart Surgery

BACKGROUND

Cardiac troponin T has been found to be accurate predictor of complications and adverse clinical events after pediatric cardiac surgery. Contrary to adult cardiac surgery, the relationship of troponin T to patient survival after pediatric heart surgery has not been previously studied. The purpose of this study was to determine whether troponin T could predict death after pediatric open cardiac surgery.

METHODS

This was a retrospective cohort study in which data from 1001 consecutive children having cardiac surgery during a 5-year period were studied. Perioperative variables that could influence death at 30 postoperative days were evaluated.

RESULTS

Multivariate analysis, using a forward stepwise logistic regression, showed that troponin T measured on the first postoperative day was a strong independent predictor of death at 30 days. Level of troponin T greater than 5.9 microg/L on the first postoperative day predicted death (odds ratio, 10.7; 95% confidence interval: 5.2 to 22.1) as did admission lactate level greater than 5.2 mmol/L (odds ratio, 22.2; 95% confidence interval: 9.7 to 50.8) No other variable, including postoperative creatine kinase-MB mass concentration, age, diagnosis, surgical procedure, presence of cyanosis, chromosomal anomaly or ventriculotomy, duration of cardiopulmonary bypass, or aortic cross-clamp, had any independent effect on 30-day survival.

CONCLUSIONS

Cardiac troponin T level on the first postoperative day is a powerful independent risk marker of death in pediatric cardiac surgery.

Randomized Controlled Trial of the Effects of Remote Ischemic Preconditioning on Children Undergoing Cardiac Surgery

OBJECTIVES

We conducted a randomized controlled trial of the effects of remote ischemic preconditioning (RIPC) in children undergoing repair of congenital heart defects.

BACKGROUND

Remote ischemic preconditioning reduces injury caused by ischemia-reperfusion in distant organs. Cardiopulmonary bypass (CPB) is associated with multi-system injury. We hypothesized that RIPC would modulate injury induced by CPB.

METHODS

Children undergoing repair of congenital heart defects were randomized to RIPC or control treatment. Remote ischemic preconditioning was induced by four 5-min cycles of lower limb ischemia and reperfusion using a blood pressure cuff. Measurements of lung mechanics, cytokines, and troponin I were made pre- and postoperatively.

RESULTS

Thirty-seven patients were studied. There were 20 control patients and 17 patients in the RIPC group. The mean age and weight of the RIPC and control patients were not different (0.9 +/- 0.9 years vs. 2.2 +/- 3.4 years, p = 0.4; and 6.9 +/- 2.9 kg vs. 11.5 +/- 10 kg, p = 0.06). Bypass and cross-clamp times were not different (80 +/- 24 min vs. 88 +/- 25 min, p = 0.3; and 55 +/- 13 min vs. 59 +/- 13 min, p = 0.4). Levels of troponin I postoperatively were greater in the control patients compared with the RIPC group (p = 0.04), indicating greater myocardial injury in control patients. Postoperative inotropic requirement was greater in the control patients compared with RIPC patients at both 3 and 6 h (7.9 +/- 4.7 vs. 10.9 +/- 3.2, p = 0.04; and 7.3 +/- 4.9 vs. 10.8 +/- 3.9, p = 0.03, respectively). The RIPC group had significantly lower airway resistance at 6 h postoperatively (p = 0.009).

CONCLUSIONS

This study demonstrates the myocardial protective effects of RIPC using a simple noninvasive technique of four 5-min cycles of lower limb ischemia and reperfusion. These novel data support the need for a larger study of RIPC in patients undergoing cardiac surgery.

Effect of dexamethasone on postoperative cardiac troponin T production in pediatric cardiac surgery

OBJECTIVE

Pediatric cardiac surgery is associated with a temporary rise in cardiac troponin T (cTnT) during the postoperative period. We examined whether dexamethasone given before cardiopulmonary bypass has myocardial protective effects as assessed by the postoperative production of cTnT.

DESIGN AND SETTING

Prospective randomized interventional study in the pediatric intensive care unit in a university hospital.

INTERVENTIONS

Patients were randomly allocated to act as controls or receive a single dose of dexamethasone (1 mg/kg) during induction of anesthesia.

MEASUREMENTS AND RESULTS

cTnT was measured four times postoperatively: immediately after admission to the pediatric intensive care unit (PICU) and 8, 15, and 24 h thereafter. The two groups had similar mean cTnT concentrations on PICU admission: those receiving dexamethasone 1.85 ng/ml (1.55-2.15) and those not receiving it 2 ng/ml (95% confidence interval 1.56-2.51). Concentrations of cTnT 8 h after admission to the PICU differed significantly after 8 h: 1.99 ng/ml (1.53-2.45) in those receiving dexamethasone and 3.08 ng/ml (2.46-3.69) in those not receiving it. After subgroup statistical analysis differences between the two groups remained significant only at 8 h, not those after 15 or 24 h.

CONCLUSIONS

The use of dexamethasone (1 mg/kg) before cardiopulmonary bypass is associated with a brief but significant reduction in postoperative cTnT production. The clinical significance of this effect is unclear.

Myocardial metabolic changes during pediatric cardiac surgery: a randomized study of 3 cardioplegic techniques

BACKGROUND

Blood cardioplegia and terminal warm blood cardioplegic reperfusion ("hot shot") reduce myocardial injury and improve metabolic recovery in hypoxic but not normoxic experimental models. However, there is little evidence of a benefit of either technique in pediatric clinical practice compared with crystalloid cardioplegia.

METHODS

Pediatric patients undergoing cardiac surgery were randomized to receive intermittent antegrade cold crystalloid cardioplegia, cold blood cardioplegia, or cold blood cardioplegia with a hot shot. Right ventricular biopsy specimens were collected before ischemia, at the end of ischemia, and 20 minutes after reperfusion. Cellular metabolites were analyzed. In acyanotic patients postoperative serum troponin I levels were also measured at 1, 4, 12, 24, and 48 hours.

RESULTS

Of 103 patients recruited, 32 (22 acyanotic and 10 cyanotic), 36 (24 acyanotic and 12 cyanotic), and 35 (25 acyanotic and 10 cyanotic), respectively, were allocated to the groups receiving cold crystalloid cardioplegia, cold blood cardioplegia, and cold blood cardioplegia with a hot shot. Cyanotic patients were younger, with longer crossclamp times. There were no significant differences in clinical outcomes between cardioplegic methods. The cardioplegic method had no overall effect in terms of adenosine triphosphate, ln(adenosine triphosphate/adenosine diphosphate), or ln(glutamate) in acyanotic patients (P =.11, P =.66, and P =.30, respectively). Also, there was no significant difference between groups in troponin I release. However, in cyanotic patients cold blood cardioplegia with a hot shot significantly reduced the decrease in adenosine triphosphate, ln(adenosine triphosphate/adenosine diphosphate), and glutamate observed at the end of ischemia and after reperfusion compared with the decrease seen in those receiving cold crystalloid cardioplegia (P =.002, P =.003, and P =.008, respectively), with cold blood cardioplegia representing an intermediate.

CONCLUSIONS

For cyanotic patients (younger, with longer crossclamp times), cold blood cardioplegia with a hot shot is the best method of myocardial protection. For acyanotic patients (older, with shorter crossclamp times), cardioplegic technique is not critical.