Early detection of cardiac damage with heart fatty acid-binding protein after cardiac operations

Evaluation of the cardioprotective effects of crystalloid del Nido cardioplegia solution via a rapid and accurate cardiac marker: heart-type fatty acid-binding protein

Background/aim

Our aim in this study was to compare the efficacy and safety of crystalloid del Nido solution and cold blood cardioplegia solution on clinical and laboratory parameters.

Materials and methods

Sixty patients who underwent elective coronary bypass operation between July 2019 and January 2020 were included in our study. Patients were divided into 2 groups of 30 patients using del Nido solution (DNS) and cold blood cardioplegia solution (CBCS), which were given for cardiac arrest. Demographic data, preoperative, postoperative 0th h, 6th h and 4th day creatine kinase myocardial band (CK-MB) and troponin I values were compared with a specific cardiac enzyme heart-type fatty acid-binding protein (H-FABP).

Results

We found that aortic cross clamp duration and cardiopulmonary bypass (CPB) time were shorter in patients using del Nido solution than cold blood cardioplegia solution (57.30 ± 23.57 min, 76.07 ± 27.18 min, P = 0.006) (95.07 ± 23.06 min, 114.13 ± 33.93, P = 0.014). Total cardioplegia solution volume was higher in the cold blood cardioplegia solution group (1426.67 ± 416.00 vs. 1200 ± 310.73 P = 0.02). Preoperative and postoperative levels of cardiac enzymes including CK-MB, troponin I and H-FABP were comparable in del Nido solution and cold blood cardioplegia solution groups.

Conclusion

According to these results, when we compare both demographic data and CK-MB, troponin I and H-FABP levels, both cardioplegia solutions were comparable regarding safety and efficacy in terms of myocardial protection.

Development of a Quantitative Detection Card for Heart-type Fatty Acid-binding Protein based on Background Fluorescence Quenching Immune Chromatography

Background

To establish a fast and simple quantitative method for detection of heart-type fatty acid-binding protein (H-FABP) in serum based on a background fluorescence quenching immunochromatographic assay.

Methods

A detection card based on the double-antibody sandwich double-antibody method with background fluorescence quenching was developed for quantitative measurement of H-FABP in serum. The optimal concentrations of control for coating the test and control lines were determined as well as the concentrations of gold-labeled antibodies used in preparing the detection system. The detection method for H-FABP in serum was established and validated using real-world clinical samples.

Results

The optimal concentrations of labeling antibody and coating antibody were 5.0 μg/mL and 1.0 mg/mL, respectively. The test card had a sensitivity of 1.15 ng/mL over a linear concentration range of 0–100 ng/mL. Based on three batches prepared for testing the card, the relative standard deviation (RSD) within batches was less than 15% without a significant difference (P=0.942). The detection method was tested against common interfering substances in serum, such as bilirubin, triglyceride and serum anticoagulants ethylenediamine tetraacetic acid (EDTA), heparin, and sodium citrate, and no significant cross-reaction was detected. The test method was further validated with 50 clinical serum samples, and the test results were comparable with standard reference detection methods with good correlation (R=0.95).

Conclusion

Our study presents a new method with strong specificity and sensitivity for the detection of H-FABP in serum, which could promote H-FABP detection in a broad range of applications.

Relationship Between Level of Heart Type Fatty Acid Binding Protein (Before and after Procedures) with Acute Renal Failure after PCI in Patients Under PCI

BACKGROUND & OBJECTIVE

Acute renal failure (AKI) is one of the most important complications of PCI. Due to delay in creatinine increase, we need specific factors to detect AKI earlier. The aim of this study is to evaluate the valuable factors by focusing on HFAB-P that can be predictive for AKI after Percutaneous Coronary Intervention (PCI).

METHODS

This prospective study was performed on 95 patients (55 males and 44 females aged between 49-78 years) under PCI in Golestan and Imam Khomeini hospitals in Ahvaz. Patients were divided into three groups based on the development of AKI after the procedure: no AKI, severe AKI (doubling of serum creatinine or needing dialysis) and any type of AKI (increased creatinine ≥ 0/3 mg/dl or a 50% increase in the means of 1/5 times serum creatinine). The demographic and clinical characteristics of the patients, the medical history and the results of the HFABP marker, GFR, and creatinine before and after PCI were evaluated for all patients.

RESULTS

The progenies showed 6 patients with severe AKI, 17 patients with any type of AKI, and 72 patients without AKI. Diabetes (P = 0.003), hypertension (P = 0.027), gender of patients (P = 0.025) and hospital admission days (P <0.001) were significantly different among the groups. Patients' age and positive troponin were significantly higher in patients with AKI. HFABP was the only factor that had significant changes before and after PCI (P <0.001). The cut-off value of HFABP was 4.69 with 95.6% sensitivity and 84.7% specificity. It has a good negative predictive value of 98.39% which suggests it to be a good test for the AKI prediction. Glomerular Filtration Rate (GFR) and creatinine (Cr) were significantly different after PCI (P <0.001).

CONCLUSION

HFABP can be considered as a predictor for AKI after PCI. Moreover, our study suggests that evaluating several parameters such as Cr and GFR before and after PCI can predict the AKI development after PCI.

Heart-Type Fatty Acid Binding Protein and Ischemia-Modified Albumin for Detection of Myocardial Infarction After Coronary Artery Bypass Graft Surgery

BACKGROUND

Heart-type fatty acid binding protein (hFABP) and ischemia-modified albumin (IMA) have been put forward as novel biomarkers to detect myocardial injury shortly after onset of ischemia. We compared hFABP and IMA with cardiac troponin I (cTnI) for speed and reliability in the diagnosis of perioperative myocardial infarction (PMI) after coronary artery bypass graft surgery (CABG).

METHODS

In all, 210 consecutive patients undergoing isolated CABG with cardiopulmonary bypass were enrolled in a prospective study. Blood samples were taken perioperatively and throughout the first 72 hours after surgery; clinical data and events were recorded. In cohort A, serum concentrations of hFABP and cTnI were measured using a combined quantitative bedside assay. In cohort B, IMA and cTnI serum concentrations were measured using an albumin cobalt binding test. Perioperative myocardial infarction was defined using a cTnI cutoff of greater than 10.5 ng/mL occurring within 24 hours of CABG or new electrocardiographic changes.

RESULTS

In cohort A, 14 patients were identified with PMI (group 1), whereas 94 had no PMI and served as controls (group 2). Both hFABP and cTnI were increased in group 1 as compared with group 2 (p < 0.001). Although cTnI did not differ before 12 hours, hFABP diverged much earlier, at 1 hour postoperatively (p < 0.001). An hFABP concentration of 20 μg/mL at 1 hour detected PMI with an area under the curve of 77.1%. In cohort B, 18 patients were identified with PMI (group 3), and 84 patients served as controls (group 4). No difference in cTnI values could be observed between the groups until 12 hours postoperatively. Ischemia-modified albumin failed to differentiate at any postoperative time point; the low discriminative power of IMA was confirmed with an area under the curve of 53.3% at 1 hour, 48.5% at 6 hours, and 39.3% at 12 hours postoperatively.

CONCLUSIONS

Heart-type fatty acid binding protein is a sensitive and rapid biomarker that detected PMI reliably at 1 hour after CABG, much earlier than cTnI. The diagnostic value of IMA for detection of PMI appears to be very limited in this setting.

Perioperative heart-type fatty acid binding protein is associated with acute kidney injury after cardiac surgery

Acute Kidney Injury (AKI) is a common complication after cardiac surgery and is associated with worse outcomes. Since heart fatty acid binding protein (H-FABP) is a myocardial protein that detects cardiac injury, we sought to determine if plasma H-FABP was associated with AKI in the TRIBE-AKI cohort; a multi-center cohort of 1219 patients at high risk for AKI who underwent cardiac surgery. The primary outcomes of interest were any AKI (Acute Kidney Injury Network (AKIN) stage 1 or higher) and severe AKI (AKIN stage 2 or higher). The secondary outcome was long-term mortality after discharge. Patients who developed AKI had higher levels of H-FABP pre- and post-operatively than patients who did not have AKI. In analyses adjusted for known AKI risk factors, first post-operative log(H-FABP) was associated with severe AKI (adjusted OR 5.39 [95% CI, 2.87-10.11] per unit increase), while pre-operative log(H-FABP) was associated with any AKI (2.07 [1.48-2.89]) and mortality (1.67 [1.17-2.37]). These relationships persisted after adjustment for change in serum creatinine (for first postoperative log(H-FABP)) and biomarkers of cardiac and kidney injury, including brain natriuretic peptide, cardiac troponin-I, interleukin-18, liver fatty acid binding protein, kidney injury molecule-1, and neutrophil gelatinase associated lipocalin. Thus, peri-operative plasma H-FABP levels may be used for risk-stratification of AKI and mortality following cardiac surgery.

High peripheral levels of h-FABP are associated with poor prognosis in end-stage heart failure patients with mechanical circulatory support

Aim: To associate the time-course of h-FABP and N-terminal pro B-type natriuretic peptide (NT-proBNP)after left ventricular assist device (LVAD) implantation to outcome in end-stage heart failure patients. Materials & methods: Patients (n = 14, NYHA class III/IV; left ventricular ejection fraction <25% were enrolled; ten survived up to 1 month after LVAD (survivors) and four died of multiorgan failure within 2 weeks (nonsurvivors). Blood samples were obtained at admission; at 4, 24 and 72 h; and at 1 and 4 weeks after LVAD. Results: h-FABP significantly increases after surgery, decreasing since 72 h in all patients. At 72 h all survivor patients present h-FABP lower than the median value. N-terminal pro B-type natriuretic peptide is not associated with patient outcome at any time. Conclusion: High h-FABP levels, indicating the presence of more severe myocardial damage, are associated with a poor prognosis in patients with LVAD, suggesting that an early cardiac injury marker could improve the prediction of clinical outcome.

Heart type fatty acid binding protein: structure, function and biosensing applications for early detection of myocardial infarction

Heart type fatty acid binding protein (HFABP) as an early marker of cardiac injury holds a promising future with studies indicating surpassing performance as compared to myoglobin. As a plasma marker, this cytoplasmic protein owing to its small size (∼15kDa) and water solubility, appears readily in the blood-stream following cardiomyocyte damage, reaching peak levels within 6h of symptom onset. Low plasma levels of HFABP as compared to tissue levels indicate that minute amounts of the protein when released during myocardial infarction leads to a greater proportional rise. These parameters of kinetic release make it an ideal candidate for rapid assessment of acute myocardial infarction (AMI). The need for development of rapid immunoassays and immunotests so as to use HFABP as an early marker for AMI exclusion is tremendous. In the present review, we outline the various immunoassays and immunosensors developed so far for the detection of HFABP in buffer, plasma or whole blood. The principles behind the detection techniques along with their performance parameters compared to standard ELISA techniques are elucidated.

Heart-type fatty acid binding protein is an independent predictor of death and ventricular dysfunction after coronary artery bypass graft surgery

BACKGROUND

Heart-type fatty acid binding protein (hFABP) functions as a myocardial fatty acid transporter and is released into the circulation early after myocardial injury. We hypothesized that hFABP is superior to conventional cardiac biomarkers for predicting early perioperative myocardial injury after coronary artery bypass graft (CABG) surgery.

METHODS

A prospective cohort study of 1298 patients undergoing primary CABG with cardiopulmonary bypass (CPB) was performed at 2 institutions. Four plasma myocardial injury biomarkers (hFABP; cardiac troponin I [cTnI]; creatine kinase, MB [CK-MB] fraction; and myoglobin) were measured at 7 perioperative time points. The association among perioperative cardiac biomarkers and ventricular dysfunction, hospital length of stay (HLOS), and up to 5-year postoperative mortality (median 3.3 years) was assessed using Cox proportional hazard models. We defined in-hospital ventricular dysfunction as a new requirement for 2 or more inotropes, or new placement of an intraaortic balloon pump, or ventricular assist device either during the intraoperative period after the patient separated from CPB or postoperatively in the intensive care unit.

RESULTS

The positive and negative predictive values of mortality for hFABP are 13% (95% confidence interval [CI], 9%-19%) and 95% (95% CI, 94%-96%), respectively, which is higher than for cTnI and CK-MB. After adjusting for clinical predictors, both postoperative day (POD) 1 and peak hFABP levels were independent predictors of ventricular dysfunction (P < 0.0001), HLOS (P < 0.05), and 5-year mortality (P < 0.0001) after CABG surgery. Furthermore, POD1 and peak hFABP levels were significantly superior to other evaluated biomarkers for predicting mortality. In a repeated-measures analysis, hFABP outperformed all other models of fit for HLOS. Patients with POD2 hFABP levels higher than post-CPB hFABP levels had an increased mortality compared with those patients whose POD2 hFABP levels decreased from their post-CPB level (hazard ratio, 10.9; 95% CI, 5.0-23.7; P = 7.2 × 10(-10)). Mortality in the 120 patients (10%) with a later hFABP peak was 18.3%, compared with 4.7% in those who did not peak later. Alternatively, for cTnI or CK-MB, no difference in mortality was detected.

CONCLUSION

Compared with traditional markers of myocardial injury after CABG surgery, hFABP peaks earlier and is a superior independent predictor of postoperative mortality and ventricular dysfunction.

Heart fatty acid binding protein in the diagnosis of myocardial infarction: where do we stand today?

Heart fatty acid binding protein (hFABP) is a novel small cytosolic protein that is abundant in the heart. It is highly cardiac-specific (i.e. expressed primarily in cardiac tissue), but is also expressed at low concentrations in tissues outside the heart. After myocardial ischemic damage, hFABP can be detected in the blood as early as 1-3 h after onset of chest pain, with peak values reached at 6-8 h and plasma levels returning to normal within 24-30 h. hFABP's clinical diagnostic value is very limited in the presence of renal failure and skeletal muscle diseases as it is completely renally eliminated. In these conditions, the diagnosis of acute myocardial infarction (AMI) may be overestimated. The combination of initial hFABP release after symptom onset, rapid kidney clearance from the circulation and high cardiac specificity suggests great potential for clinical use. Serial measurements of hFABP in the first 24 h after onset of symptoms in AMI patients can: (a) identify patients who are susceptible to reperfusion strategies, (b) detect perioperative AMIs, (c) distinguish patients who reperfuse their infarct-related artery from those who do not, as early as 30 min after starting thrombolytic treatment, (d) detect re-infarction if it occurs within 10 h after symptom onset, and (e) permit an accurate estimation of myocardial infarct size providing important prognosis information.

Bioenzymatic detection of troponin C using micro-opto-electro-mechanical systems

Diagnosis and monitoring of critical diseases such as acute myocardial infarction (AMI) require a quantitative analysis of biological molecules. A high-throughput identification of these biological molecules can be generated by using micro-electro-mechanical systems (MEMS) structures like simple cantilever beams, which respond to the intermolecular forces resulting from binding these molecules. Biochemical markers like troponin C are considered the primary markers for myocardial injury and have generated considerable interest. A 26-residue lytic membrane protein of bee venom melittin (ME) is chosen to interact with rabbit skeletal muscle troponin C (TnC) on the surface of the cantilever beams. An optical beam deflection method is employed to identify the enzymatic reaction on the surface of the cantilever due to these proteins. Identification of these proteins is also done using fluorescence spectroscopy (FS) to compliment the optical monitored deflection method. A second set of proteins like horse radish peroxide (HRP) and hydrogen peroxide (H2O2) are applied to atomic force microscopy (AFM) cantilever beams to study their behavior under the enzymatic reactions of proteins. Identification of these proteins is done using Fourier transform infrared spectroscopy (FTIR). An analytical model of the cantilever beam is developed, and its mode shapes are studied by employing orthogonal polynomials in the classic Rayleigh-Ritz method. The surface stress caused by the enzymatic reaction of the proteins that leads to pure bending on the top surface of the cantilever is evaluated. The information provided by the experimental and analytical modeling reported in this work will be useful in the development of a portable biosensor for the detection of AMI.

Dexamethasone: Benefit and Prejudice for Patients Undergoing On-Pump Coronary Artery Bypass Grafting

STUDY OBJECTIVES

Cardiac surgery with cardiopulmonary bypass (CPB) results in perioperative organ damage caused by the systemic inflammatory response syndrome (SIRS) and ischemia/reperfusion injury. Administration of corticosteroids before CPB has been demonstrated to inhibit the activation of the systemic inflammatory response. However, the clinical benefits of corticosteroid therapy are controversial. This study was designed to document the effects of dexamethasone on cytokine release and perioperative myocardial, pulmonary, renal, intestinal, and hepatic damage, as assessed by specific and sensitive biomarkers.

DESIGN AND PATIENTS

A prospective, double-blind, placebo-controlled, randomized trial for dexamethasone was conducted in 20 patients receiving either dexamethasone (1 mg/kg before anesthesia induction and 0.5 mg/kg after 8 h; n = 10) or placebo (n = 10). Different markers were used to assess the SIRS: interleukin (IL)-6, IL-8, IL-10, C-reactive protein (CRP), and tryptase; and organ damage: heart (plasma heart-type fatty acid binding protein, cardiac troponin I [cTnI], creatine kinase-MB), kidneys (N-acetyl-glucosaminidase [NAG], microalbuminuria), intestine (intestinal-type fatty acid binding protein [I-FABP]/liver-type fatty acid binding protein [L-FABP]), and liver (alpha-glutathione S-transferase).

RESULTS

Dexamethasone modulated the SIRS with lower proinflammatory (IL-6, IL-8) and higher antiinflammatory (IL-10) IL levels. CRP and tryptase were lower in the dexamethasone group. cTnI values were lower in the dexamethasone group at 6 h in the ICU (p = 0.009). Patients in the dexamethasone group had a longer time to tracheal extubation (18.86 +/- 1.13 h vs 15.01 +/- 0.99 h, p = 0.02 [mean +/- SEM]), with a lower oxygenation index at that time: Pa(O2)/fraction of inspired oxygen ratio, 37.17 +/- 1.8 kPa vs 29.95 +/- 2.1 kPa (p = 0.009). The postoperative glucose level (10.7 +/- 0.6 mmol/L vs 7.4 +/- 0.5 mmol/L, p = 0.005) was higher in the dexamethasone group. Serum glucose was independently associated with intestinal injury (urine I-FABP peak, R2 = 42.5%, beta = 114.4 +/- 31.4, significant at p = 0.002; urine L-FABP peak, R2 = 47.3%, beta = 7,714.1 +/- 1,920.9, significant at p = 0.001) and renal injury (urine NAG, R2 = 32.1%, beta = 0.21 +/- 0.07, significant at p = 0.009). Tryptase peaks correlated negatively with peaks of intestinal and renal injury biomarkers.

CONCLUSION

Even while inhibiting SIRS, dexamethasone treatment offered no protection against transient, subclinical, perioperative abdominal organ damage. Tryptase release could have a preconditioning effect, offering protection against perioperative intestinal and renal damage. Dexamethasone treatment resulted in more pronounced postoperative pulmonary dysfunction, prolonged time to tracheal extubation, and initiated postoperative hyperglycemia in patients undergoing elective on-pump coronary artery bypass graft surgery.

Performance of a semi-quantitative whole blood test for human heart-type fatty acid-binding protein (H-FABP)

OBJECTIVES

We evaluated the accuracy of visually reading the whole blood Rapicheck H-FABP panel test using the quantitative plasma H-FABP concentration as the reference.

SUBJECTS AND METHODS

Consecutive patients with chest pain (n = 237) who were suspected of having acute myocardial infarction were recruited. The appearance of an evident test line within 5 min was given a grade of +3 (strongly positive), appearance within 15 min +2 (moderately positive) and the appearance of a weak test line within 15 min +1 (weakly positive).

RESULTS AND DISCUSSION

The concordance rates were 91.8% for positive, 70.1% for negative and 80.2% for overall. Plasma H-FABP concentrations were above the cut-off value for 9.2% of negative (0) results. Fifty percent of weakly positive (+1) and 25.0% of moderately positive (+2) results had H-FABP concentrations lower than the cut-off value. All of the strongly positive (+3) were above the cut-off value. These results suggested that the false-positive and false-negative results of Rapicheck H-FABP were caused by over or underestimation in visual reading when the plasma H-FABP concentration was near the cut-off concentration.

CONCLUSIONS

Low accuracy of visual reading of Rapicheck H-FABP was due to poor estimation by manual reading around the cut-off value.

Effects of autotransfusion of mediastinal shed blood on biochemical markers of myocardial damage in coronary surgery

BACKGROUND

Previous studies have shown conflicting results regarding the effect of autotransfusion of mediastinal shed blood after coronary artery bypass grafting (CABG) on the serum levels of myocardial band (MB) isoenzymes of creatine kinase (CK-MB) and cardiac troponins. The effect of autotransfusion on serum levels of human heart fatty acid binding protein (H-FABP), another marker of myocardial necrosis, has not been studied. The aim of the present study was to investigate the effects of autotransfusion of mediastinal shed blood on the serum levels of CK-MB, cardiac troponin T (cTnT), and H-FABP after uncomplicated primary CABG.

METHODS

Fifty patients were randomized to post-operative autotransfusion of mediastinal shed blood or no autotransfusion. Blood samples for the analysis of the biochemical markers of myocardial damage were drawn pre-operatively and 1, 4, 12, 24, 48, and 72 h after the termination of cardiopulmonary bypass. Samples from the mediastinal shed blood were collected after 1 and 4 h.

RESULTS

The levels of the biochemical markers of myocardial injury were all markedly elevated in mediastinal shed blood. Autotransfusion did not significantly affect the serum levels of cTnT or H-FABP. However, during the early post-operative hours, there was a trend towards a higher level of cTnT and H-FABP in the autotransfusion group. During the first 24 h after surgery, the autotransfusion group had a significantly higher serum level of CK-MB.

CONCLUSION

Post-operative autotransfusion of mediastinal shed blood may contribute to elevated serum levels of biochemical markers of myocardial injury.

Heart fatty acid binding protein in the rapid evaluation of myocardial damage following valve replacement surgery

BACKGROUND

Myocardial damage occurs following valve replacement surgery. We estimated the value of heart fatty acid binding protein (H-FABP) in these patients.

METHODS

Sixty elected patients were enrolled and distributed into single (group A) and double (group B) valve replacement groups. The clinical data were outlined and blood samples were collected perioperatively for determination of plasma levels of H-FABP, cardiac troponin-I (cTn-I), and CK-MB in both groups.

RESULTS

56 patients completed the study and no significant difference of clinical data was observed except CPB time and ACC time between groups. H-FABP level elevated quickly after reperfusion and peaked significantly earlier than cTn-I and CK-MB, it also declined rapidly but did not return to baseline at 24 h after reperfusion. Three markers' levels were all higher in group B than in group A after reperfusion with significant differences at their peaks and thereafter. Patients with postoperative complications had significantly higher H-FABP levels than usual. H-FABP peak level associated well with the length of CPB and ACC as well as with other 2 markers' peak levels in both groups.

CONCLUSION

Compared with cTn-I and CK-MB, H-FABP is an earlier and potentially useful marker in the rapid evaluation of myocardial damage following valve replacement surgery with CPB.

Fatty acid-binding proteins as plasma markers of tissue injury

BACKGROUND

One of the novel and promising plasma markers for detection of tissue injury is the family of 15 kDa cytoplasmic fatty acid-binding proteins of which various tissue-specific types occur.

AIMS AND OBJECTIVES

The present status of heart-type fatty acid-binding protein (H-FABP) as a diagnostic and prognostic marker for acute and chronic cardiac injury, as well as the preliminary diagnostic use of other types of FABP for detecting injury in other organs, is reviewed.

METHODS

This review is based on an overview of the literature on clinical diagnostics of various forms of organ injury, and uses additional literature on physiological aspects relevant for the interpretation of plasma marker concentrations.

RESULTS

H-FABP not only proves to be an excellent early marker for cardiac injury in acute coronary syndromes, but also allows detection of minor myocardial injury in heart failure and unstable angina. Preliminary results indicate that sensitivity, rule-out power and prognostic value of H-FABP in cardiac injury surpass the performance of the standard early marker myoglobin. The liver only contains liver-type FABP (L-FABP), but co-expression of H-FABP and L-FABP occurs in the kidney. Similarly, intestinal-type FABP (I-FABP) and L-FABP are found in intestines, and brain-type FABP (B-FABP) and H-FABP occur in the brain. Preliminary but promising applications of these proteins have been demonstrated for liver rejection, viability selection of kidneys from non-heart-beating donors (NHBD), inflammatory and ischemic bowel disease, traumatic brain injury and in the prevention of muscle injury in trained athletes.

CONCLUSIONS

Further study of the diagnostic and prognostic use of various FABP types is warranted, but their clinical application will require further commercialization of automated and rapid assays.

The dependence of myocardial damage on age and ischemic time in pediatric cardiac surgery

OBJECTIVE

Heart fatty acid-binding protein is a rapid indicator for assessment of myocardial damage in cardiac surgery. The purpose of this study was to investigate the effects of age and ischemic time on the biochemical evidence and clinical outcomes of myocardial damage in pediatric cardiac surgery.

METHODS

A prospective observational cohort study conducted over 2.5 years was performed in 98 consecutive patients (51 infants and 47 children) undergoing cardiac surgery for ventricular septal defects. Serial measurements of serum levels of heart fatty acid-binding protein and the respective areas under the curve were obtained, with particular reference to age and aortic crossclamp time. Assessment of clinical outcomes included inotropic support, ventilatory support, and intensive care unit stay.

RESULTS

There was a linear dependence of the logarithm of age and the logarithm of heart fatty acid-binding protein release(r = 0.737, P < .0001). This logarithm-logarithm plot showed a power function of age for heart fatty acid-binding protein release. The exponent and amplitude parameter of the power function was the aortic crossclamp time. Compared with children, infants had significantly more myocardial damage and worse clinical outcomes, and these factors were related to the aortic crossclamp time.

CONCLUSIONS

The younger the age of patients, the more vulnerable are their myocardia to injury caused by ischemia during definitive repair of congenital heart disease. Therefore, perioperative management for pediatric patients after cardiac surgery should be performed, taking into consideration the dependence of the myocardial damage on age and ischemic time.

Prophylactic Effect of Intravenous Nicorandil on Perioperative Myocardial Damage in Patients Undergoing Off-Pump Coronary Artery Bypass Surgery

Nicorandil, ATP sensitive potassium channel opener, is shown to reduce coronary events for patients with stable angina. The present study was designed to examine the protective potential of nicorandil for patients undergoing off-pump coronary artery bypass grafting. Twenty-four patients undergoing off-pump coronary artery bypass grafting were randomly assigned to two groups, one receiving continuous infusion of nicorandil (1.0 microg.kg(-1).min(-1)) (n = 12) through anesthesia to next day and the other receiving no nicorandil for control (n = 12). For assessing myocardial injury, heart type fatty acid binding protein, troponin T, and creatine kinase MB isoform were determined during the first 15 hours after reperfusion. The concentration of heart type fatty acid binding protein in the nicorandil group was significantly lower than that in the control group. On the other hand, the concentrations of troponin T and creatine kinase MB isoform in the nicorandil group were lower than those in the control group, but the differences did not reach statistical significance. Furthermore, nicorandil did not affect the patients' hemodynamic variables. Our data suggest that the infusion of nicorandil provides small myocardial protection without affecting hemodynamic parameters during perioperative treatment of patients undergoing off-pump coronary artery bypass grafting.

Evaluation of heart fatty acid–binding protein as a rapid indicator for assessment of myocardial damage in pediatric cardiac surgery

OBJECTIVES

Perioperative myocardial damage is a major determinant of postoperative cardiac dysfunction for congenital heart disease. Heart fatty acid-binding protein is reported to be a rapid marker of perioperative myocardial damage that peaks earlier than creatine kinase isoenzyme MB or cardiac troponin T in adults. The objective of this study was to assess the suitability of using serum concentrations of heart fatty acid-binding protein for evaluation of perioperative myocardial damage in pediatric cardiac surgery.

METHODS

After institutional review board approval and informed consent, 100 children undergoing open procedures for congenital heart disease were prospectively enrolled in the study. Mean age at operation was 4.9 +/- 0.4 years. Serum concentrations of heart fatty acid-binding protein, creatine kinase isoenzyme MB, and cardiac troponin T were measured serially before operation and at 0, 1, 2, 3, and 6 hours after aortic declamping. Relationships between serum peak level of heart fatty acid-binding protein and intraoperative and postoperative clinical variables were evaluated.

RESULTS

Serum heart fatty acid-binding protein reached its peak level at 1 hour after declamping in 95 patients (95%), which was significantly earlier (P <.01) than serum creatine kinase isoenzyme MB or cardiac troponin T. In addition, serum heart fatty acid-binding protein level immediately after declamping correlated strongly with serum peak heart fatty acid-binding protein level (r = 0.91, P <.01). The serum peak level of heart fatty acid-binding protein correlated with those of creatine kinase isoenzyme MB (r = 0.77, P <.01) and cardiac troponin T (r = 0.80, P <.01). In the forward stepwise multiple regression analysis, age (P <.0001), aortic crossclamp time (P <.0001), the presence of a ventriculotomy (P <.001), and the lowest hematocrit level during cardiopulmonary bypass (P <.05) were significant intraoperative variables that influenced the release of heart fatty acid-binding protein. There were significant relationships between serum peak heart fatty acid-binding protein level and postoperative inotropic support, duration of intubation, and intensive care unit stay (P <.01 for each).

CONCLUSIONS

Heart fatty acid-binding protein is a rapid marker for assessment of myocardial damage and clinical outcome in pediatric cardiac surgery. In particular, serum heart fatty acid-binding protein level immediately after aortic declamping may be a potentially useful prognostic indicator of myocardial damage as well as clinical outcome in pediatric cardiac surgery.

Do we need additional markers of myocyte necrosis: the potential value of heart fatty-acid-binding protein

Heart fatty-acid-binding protein (FABP) is a small cytosolic protein that is abundant in the heart and has low concentrations in the blood and in tissues outside the heart. It appears in the blood as early as 1.5 h after onset of symptoms of infarction, peaks around 6 h and returns to baseline values in 24 h. These features of H-FABP make it an excellent potential candidate for the detection of acute myocardial infarction (AMI). We review the strengths and weaknesses of H-FABP as a clinically applicable marker of myocyte necrosis in the context of acute coronary syndromes.

Plasma brain natriuretic peptide reflects left ventricular function during percutaneous cardiopulmonary support

BACKGROUND

Plasma levels of brain natriuretic peptide (BNP), a cardiac hormone secreted predominantly from the ventricle, are elevated in patients with myocardial infarction, hypertension, and dilated cardiomyopathy. In this study, we assessed the usefulness of measuring BNP to evaluate left ventricular function in patients with severe heart failure receiving mechanical circulatory support.

METHODS

Plasma BNP and creatine kinase (CK)-MB levels were measured serially in 8 consecutive patients with cardiogenic shock who received percutaneous cardiopulmonary support (PCPS) at Osaka Police Hospital from August 1999 to March 2000. Coronary artery bypass grafting or percutaneous transluminal coronary angioplasty was also performed in 5 patients during PCPS; in addition, 1 patient underwent insertion of a left ventricular venting catheter and implantation of a left ventricular assist system after PCPS.

RESULTS

Five patients were weaned from PCPS, and 3 died. In survivors, plasma BNP and CK-MB levels correlated positively and significantly (r = 0.968, p = 0.03). After PCPS was initiated, plasma BNP levels gradually decreased in survivors, but not in patients who died (p = 0.003).

CONCLUSIONS

These results suggest that plasma BNP levels accurately reflect myocardial damage in patients undergoing PCPS. A decrease in BNP might appear to indicate improved left ventricular function and predict successful weaning from mechanical support.

Controlled nicorandil administration for myocardial protection during coronary artery bypass grafting under cardiopulmonary bypass

Nicorandil is a hybrid potassium channel opener, and recent experimental studies have demonstrated its efficacy in myocardial protection against ischemia-reperfusion. This clinical study was designed to examine the myocardial protective effect of nicorandil administered during cardiopulmonary bypass. Seventy adult patients, 53 men and 17 women, undergoing elective coronary artery bypass grafting were randomly assigned to two groups, one receiving nicorandil during cardiopulmonary bypass (group N, n = 35) and the other receiving no nicorandil for control (group C, n = 35). Nicorandil was administered at each dose of 0.1 mg/kg into the cardiopulmonary bypass circuit according to the following schedule: (1) bolus injection at the initiation of cardiopulmonary bypass, (2) continuous infusion for 5 min before aortic cross-clamping, (3) bolus administration at 5 min before reperfusion, and (4) continuous infusion for 5 min before reperfusion. The time required for achieving cardiac arrest after the initial cardioplegia was significantly reduced in group N in comparison with that in group C. After aortic unclamping, the number of patients showing a significant ST segment change on the electrocardiogram was significantly fewer in group N, whereas the number of patients showing spontaneous recovery of heart beat was significantly greater. As for the myocardial protective effect, group N showed lower plasma levels of malondialdehyde, human-heart fatty acid-binding protein, and peak creatine kinase-MB, and required lower doses of catecholamine. Our results suggest that nicorandil administration during cardiopulmonary bypass provides enhanced myocardial protective effects against ischemia-reperfusion in patients undergoing coronary artery bypass grafting.

Heart-type fatty acid binding protein (hFABP) in the diagnosis of myocardial damage in coronary artery bypass grafting

OBJECTIVES

Heart-type fatty acid binding protein (hFABP) is an intracellular molecule engaged in the transport of fatty acids through myocardial cytoplasm and has been used as a rapid marker of myocardial infarction. However, its value in the evaluation of perioperative myocardial injury has not yet been assessed.

METHODS

32 consecutive patients undergoing coronary artery bypass grafting were included in a prospective, randomized study using standardized operative procedures and myocardial protection. Three patients with perioperative myocardial infarction were added. Serial blood samples were taken preoperatively, before ischemia, 5 and 60 min after declamping, 1 and 6 h postoperatively and on postoperative days 1, 2 and 10 and were tested for hFABP, creatine kinase isoenzyme MB (CKMB) and troponin I (TnI).

RESULTS

Hospital mortality was zero. The kinetics of the biochemical parameters revealed a typical pattern for each marker. In routine patients, hFABP levels peaked as early as 1 h after declamping, whereas CKMB and TnI peaked only 1 h after arrival in the intensive care unit. Patients with perioperative infarction displayed peak levels some hours later in all marker proteins. Peak serum levels of hFABP correlated significantly with peak levels of CKMB (r=0.436, P=0.011) and TnI (r=0.548, P=0.001), indicating the degree of myocardial damage.

CONCLUSIONS

hFABP is a rapid marker of perioperative myocardial damage and peaks earlier than CKMB or TnI. The kinetics of marker proteins in serial samples immediately after reperfusion is more suitable for the detection of perioperative myocardial infarction than a fixed cut-off level.

Development of a simple whole blood panel test for detection of human heart-type fatty acid-binding protein

OBJECTIVE

For the diagnosis of acute myocardial infarction (AMI), we have developed a rapid and simple whole blood panel test for the detection of human heart-type fatty acid-binding protein (H-FABP) using one-step immunochromatography.

METHODS AND RESULTS

We have developed a whole blood panel test for rapid detection of human H-FABP using a one-step immunochromatography technique. The result of this panel test was not affected by the other contents of the blood such as bilirubin, hemoglobin and others. Furthermore, no cross-reactivity of the antibodies was found with other cardiac markers or other tissue-type FABPs. The result of this panel test was similar to the diagnostic cut-off value, 6.2 ng of H-FABP per mL of serum which was evaluated by the enzyme-linked immunosorbent assay (ELISA).

CONCLUSION

We have developed a simple one-step immunochromatography technique to detect H-FABP in whole blood sample. Further studies are required to identify the value of this point-of-care testing (POCT) as a diagnostic marker for AMI.

Clinical evaluation of leukocyte-depleted blood cardioplegia for pediatric open heart operation

BACKGROUND

Blood cardioplegia (BCP) is widely used for myocardial protection during open heart operation. However, BCP may have a chance to induce neutrophil-mediated myocardial injury during aortic cross-clamping. We clinically evaluated the myocardial protective effect of leukocyte-depleted blood cardioplegia (LDBCP) for initial and intermittent BCP administration in pediatric patients.

METHODS

Fifty patients undergoing open heart operation for congenital heart disease between January 1997 and March 1999 were reviewed. Twenty-five were administered LDBCP for myocardial protection during ischemic periods (LDBCP group), and the remaining 25 were given BCP without leukocyte depletion (BCP group).

RESULTS

The difference in plasma concentrations of malondialdehyde between coronary sinus effluent blood and arterial blood just after reperfusion in the LDBCP group (1.68 +/- 0.56 micromol/L) was significantly lower than that in the BCP group (2.35 +/- 0.62 micromol/L; p < 0.01). The LDBCP group showed significantly lower plasma concentrations of human heart fatty acid-binding protein at 50 minutes after reperfusion (LDBCP group, 103.5 +/- 38.7 IU/L; BCP group, 144.8 +/- 48.8 IU/L; p < 0.01) and the peak value of creatine kinase-MB during the first 24 postoperative hours (LDBCP group, 17.0 +/- 8.5 IU/L; BCP group, 26.0 +/- 11.6 IU/L; p < 0.01) than did the BCP group. The maximum dose of catecholamine was significantly smaller in the LDBCP group (LDBCP group, 3.20 +/- 2.18 microg x kg(-1) x min(-1); BCP group, 5.60 +/- 2.83 microg x kg(-1) x min(-1); p < 0.01).

CONCLUSIONS

These results suggest the usefulness of LDBCP for protection from the myocardial injury that can be induced by BCP administration during aortic cross-clamping.

Human heart-type cytoplasmic fatty acid-binding protein (H-FABP) for the diagnosis of acute myocardial infarction. Clinical evaluation of H-FABP in comparison with myoglobin and creatine kinase isoenzyme MB

Heart-type fatty acid-binding protein (H-FABP) is a low molecular weight cytoplasmic protein and present abundantly in the myocardium. When the myocardium is injured, as in the case of myocardial infarction, low molecular weight cytoplasmic proteins including H-FABP are released into the circulation and H-FABP is detectable in a blood sample. We have already developed a direct sandwich-ELISA for quantification of human H-FABP using two distinct types of monoclonal antibodies specific for human H-FABP. In this study we investigated the clinical validity of H-FABP as a biochemical diagnostic marker in the early phase of acute myocardial infarction (AMI). To evaluate the diagnostic usefulness of H-FABP in the early phase of AMI, blood samples were obtained from the following patients within 12 hours after the appearance of symptoms, and serum levels of H-FABP were compared with those of conventional diagnostic markers, such as myoglobin and creatine kinase isoenzyme MB (CK-MB). Blood samples were collected from patients with confirmed AMI (n=140), patients with chest pain who were afterwards not classified as AMI by normal CK-MB levels (non-AMI) (n=49) and normal healthy volunteers (n=75). The serum concentration of H-FABP was quantified with our direct sandwich-ELISA. The concentration of myoglobin mass was measured with a commercial RIA kit. The serum CK-MB activity was determined with an immuno-inhibition assay kit. The overall sensitivity of H-FABP, within 12 hours after the appearance of symptoms, was 92.9%, while it was 88.6% with myoglobin and 18.6% with CK-MB. The overall specificity of H-FABP was 67.3%, while it was 57.1% with myoglobin and 98.0% with CK-MB. The diagnostic efficacy rates with these markers were 86.2% (H-FABP), 80.4% (myoglobin) and 39.2% (CK-MB), respectively. The diagnostic validity of H-FABP was further assessed by receiver operating characteristic (ROC) curve analysis. The area under the curve (AUC) of H-FABP was 0.921, which was significantly greater than with myoglobin (AUC: 0.843) and CK-MB (AUC: 0.654). These parameters, such as sensitivity, specificity, diagnostic efficacy and diagnostic accuracy, obtained for patients with chest pain within 3 hours and/or 6 hours after the onset of symptoms were almost the same as those for patients within 12 hours after symptoms. H-FABP is more sensitive than both myoglobin and CK-MB, more specific than myoglobin for detecting AMI within 12 hours after the onset of symptoms, and shows the highest values for both diagnostic efficacy and ROC curve analysis. Thus, H-FABP has great potential as an excellent biochemical cardiac marker for the diagnosis of AMI in the early phase.

Plasma and urinary levels of heart fatty acid-binding protein in patients undergoing cardiac surgery

To evaluate the clinical significance of the plasma and urinary levels of heart fatty acid-binding protein (H-FABP) in patients undergoing cardiac surgery, a prospective study was conducted. Ten patients undergoing coronary artery bypass grafting were enrolled. Blood samples for determination of plasma H-FABP (pH-FABP), the MB isoenzyme of creatine kinase (CK-MB) and troponin-T (TnT), and urine samples for determination of urinary H-FABP (uH-FABP) were collected serially. None of the patients had perioperative myocardial infarction. The time to reach the peak level after aortic declamping was significantly (p<0.05) shorter for pH-FABP (1.4+/-0.5 h) than for CK-MB (2.5+/-0.5 h), TnT (6.6+/-1.3 h) or uH-FABP (3.0+/-0.6 h). Peak levels of pH-FABP correlated with those of CK-MB (r = 0.51, p = 0.04), TnT (r = 0.60, p = 0.03) and uH-FABP (r = 0.61, p = 0.03), and peak levels of uH-FABP correlated with CK-MB (r = 0.57, p = 0.04). Postoperative uH-FABP levels correlated inversely with the left ventricular stroke work index (r = -0.63, p = 0.04). This study demonstrated that H-FABP appears rapidly in plasma after reperfusion and reaches its peak earlier than other available biochemical markers; it appears also in urine and the levels correlated with cardiac function. Plasma and urinary H-FABP may be an early and sensitive biochemical marker for the diagnosis of myocardial injury in patients undergoing cardiac surgery.