Cardiac troponin T and creatine kinase predict mid-term infarct size and left ventricular function after acute myocardial infarction: A cardiac MR study

Association between engagement in exercise training and peak cardiac biomarker concentrations following ST-elevation myocardial infarction

Background

Regular exercise training is an important factor in prevention of myocardial infarction (MI). However, little is known whether exercise engagement prior to MI is related to the magnitude of post-MI cardiac biomarker concentrations and clinical outcomes.

Objectives

We tested the hypothesis that exercise engagement in the week prior MI is related to lower cardiac biomarker concentrations following ST-elevated MI (STEMI).

Methods

We recruited hospitalised STEMI patients and assessed the amount of exercise engagement in the 7 days preceding MI onset using a validated questionnaire. Patients were classified as 'exercise' if they performed any vigorous exercise in the week prior MI, or as 'control' if they did not. Post-MI peak concentrations of high-sensitive cardiac troponin T (peak-hs-cTnT) and creatine kinase (peak-CK) were examined. We also explored whether exercise engagement prior MI is related to the clinical course (duration of hospitalisation and incidence of in-hospital, 30-day and 6-month major adverse cardiac events (reinfarction, target vessel revascularisation, cardiogenic shock or death)).

Results

In total, 98 STEMI patients were included, of which 16% (n=16) was classified as 'exercise', and 84% (n=82) as 'control'. Post-MI peak-hs-cTnT and peak-CK concentrations were lower in the exercise group (941 (645-2925) ng/mL; 477 (346-1402) U/L, respectively) compared with controls (3136 (1553-4969) ng/mL, p=0.010; 1055 (596-2019) U/L, p=0.016, respectively). During follow-up, no significant differences were found between both groups.

Conclusion

Engagement in exercise is associated with lower cardiac biomarker peak concentrations following STEMI. These data could provide further support for the cardiovascular health benefits of exercise training.

Clinically Acquired High Sensitivity Cardiac Troponin T is a Poor Predictor of Reduced Left Ventricular Ejection Fraction After ST Elevation Myocardial Infarction: A National Cohort Study-ANZACS-QI 65

OBJECTIVE

Cardiac troponins (cTn) have been used historically to estimate infarct size in ST elevation myocardial infarction (STEMI). Within a resource constrained health care environment, cTn could therefore be used for prioritisation of patients for cardiac imaging, in particular echocardiography. We aimed to determine how useful routinely collected cTn would be in predicting significant left ventricular (LV) impairment.

METHODS

All patients in the All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry with their first episode of STEMI between January 2013 and November 2018, who had high sensitivity troponin T measured, were included. We excluded patients with no left ventricular ejection fraction (LVEF) assessment, known LV dysfunction, or prior myocardial infarction.

RESULTS

In total, 3,698 patients were included in the analysis. A higher mean hsTnT (admission and peak) was seen in patients with more severely impaired LV function but there was significant overlap in the range of hsTnT between the different LVEF categories. Cardiac troponins demonstrated poor discriminative ability to either predict or exclude significant LV impairment (LVEF <40%). At an optimal cutpoint of 3,405 ng/L, peak hsTnT had a sensitivity of 56.5% (95% confidence interval [CI] 42-62%), a specificity of 65.3% (95% CI 62-79%) and an area under the receiver operating curve of 0.62 (95% CI 0.60-0.64).

CONCLUSION

This is the largest study comparing clinically measured troponin levels and LV function in patients presenting with STEMI. A definite, but weak, association was seen between peak troponin and the degree of LV dysfunction, with significant overlap in troponin levels between levels of myocardial dysfunction. Routinely acquired troponin is not suitable for clinical use as a method of prioritising patients for cardiac imaging.

Intracoronary pharmacological therapy versus aspiration thrombectomy in STEMI (IPAT-STEMI): A systematic review and meta-analysis of randomized trials

BACKGROUND

Thrombus load in STEMI patients remains a challenge in practice. It aggravates coronary obstruction leading to impaired myocardial perfusion, worsened cardiac function, and adverse clinical outcomes. Various strategies have been advocated to reduce thrombus burden.

OBJECTIVES

This meta-analysis aimed to evaluate the effectiveness of intracoronary-administered thrombolytics or glycoprotein IIb/IIIa inhibitors (GPI) in comparison with aspiration thrombectomy (AT) as an adjunct to percutaneous coronary intervention (PCI) among patients presenting with ST-segment elevation myocardial infarction (STEMI).

METHODS

A comprehensive literature search for randomized trials that compared intracoronary-administered thrombolytics or GPI with AT in STEMI patients who underwent PCI, was conducted using various databases (e.g., MEDLINE, EMBASE, CENTRALE). Primary outcome was procedural measures (e.g., TIMI flow grade 3, TIMI myocardial perfusion grade (TMPG) 3, Myocardial blush grade (MBG) 2/3, ST-segment resolution (STR)).

RESULTS

Twelve randomized trials enrolled 1,466 patients: 696 were randomized to intracoronary-administered pharmacological interventions and 553 to AT. Patients randomized to PCI alone were excluded. Thrombolytics significantly improved TIMI flow grade 3 (odds ratio = 3.71, 95% CI: 1.85-7.45), complete STR (odds ratio = 3.64, 95% CI: 1.60-8.26), and TMPG 3 (odds ratio = 5.31, 95% CI: 2.48-11.36). Thrombolytics significantly reduced major adverse cardiovascular events (MACE) (odds ratio = 0.29, 95% CI: 0.13-0.65) without increasing bleeding risk. Trial sequential analysis assessment confirmed the superiority of thrombolytics for the primary outcome. Intracoronary GPI, either alone or combined with AT, did not improve procedural or clinical outcomes.

CONCLUSIONS

Compared with AT, intracoronary-administered thrombolytics significantly improved myocardial perfusion and MACE in STEMI patients.

Effects of COPD on Left Ventricular and Left Atrial Deformation in Patients with Acute Myocardial Infarction: Strain Analysis Using Speckle-Tracking Echocardiography

Myocardial strain analysis, which describes myocardial deformation (shortening or lengthening), provides more detailed information about left ventricular (LV) and atrial (LA) functions than conventional echocardiography and delivers prognostic information. To analyze the effects of COPD on left heart function upon acute myocardial infarction (AMI), consecutive AMI patients were retrospectively screened, and patients were included if a post-AMI echocardiography and results of recent pulmonary function tests (PFTs) were available. Strain analysis was performed by a cardiologist who was blinded to clinical information. Overall, 109 AMI patients were included (STEMI: 38%, non-STEMI: 62%). COPD patients (41%) had significantly more impaired LV “global-longitudinal-strain” (LV-GLS) compared to non-COPD patients (−15 ± 4% vs. −18 ± 4%; p < 0.001, respectively), even after adjusting for LV-ejection-fraction (LVEF) and age (mean estimated difference: 1.7%, p = 0.009). Furthermore, COPD patients had more impaired LA strain (LAS) than non-COPD patients in all cardiac cycle phases (estimated mean differences after adjusting for LVEF and age: during reservoir phase: −7.5% (p < 0.001); conduit phase: 5.5% (p < 0.001); contraction phase: 1.9% (p = 0.034)). There were no correlations between PFT variables and strain values. In conclusion, the presence of COPD was associated with more impaired LV and LA functions after AMI, as detected by strain analysis, which was independent of age, LVEF, and PFT variables.

Impact of Antecedent Aspirin Use on Infarct Size, Bleeding and Composite Endpoint in Patients with de Novo Acute Myocardial Infarction

BACKGROUND

The study aimed to evaluate the impact of antecedent aspirin use on infarct size, bleeding and composite endpoint in patients with de novo acute myocardial infarction.

PATIENTS AND METHODS

A total of 562 consecutive patients with de novo acute myocardial infarction were included in this prospective cohort study. Patients were assigned into two groups based on presence (n=212) and absence (n=350) of prior aspirin use. Primary endpoint was myocardial infarct size, as estimated by troponin I peak. In-hospital mortality, bleeding and composite clinical endpoint including cardiogenic shock, stroke, in-hospital mortality and major bleeding were also evaluated.

RESULTS

Although GRACE and CRUSADE scores were higher, troponin I peak was lower in prior aspirin users. This result was maintained after adjustment for baseline ischemic risk profile and other major confounders including MI type and location. Despite high CRUSADE score, there was no increase in major and minor bleeding. Minimal bleeding was higher in antecedent aspirin users. When it was adjusted for the CRUSADE score, a similar risk was reported.

CONCLUSION

Patients with de novo acute myocardial infarction using aspirin for primary prevention have an unexpectedly smaller infarct size and similar bleeding rates.

Effect of intracoronary tirofiban following aspiration thrombectomy on infarct size, in patients with large anterior ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

Myocardial recovery following primary percutaneous coronary intervention is often suboptimal despite of restoration of thrombolysis in myocardial infarction (TIMI) 3 flow, in part due to thrombus embolization which results in impairing microvascular reperfusion besides increasing infarct size. The purpose of the present study was to estimate the effect of aspiration thrombectomy followed by intracoronary delivery of tirofiban on decreasing the infarct size utilizing cardiac MRI (cMR) in large anterior ST-segment elevation myocardial infarction (STEMI) patients.

PATIENTS

A prospective randomized controlled study of 100 patients with large anterior STEMI were randomized to (Study group) using intracoronary tirofiban (intracoronary) and (control group) without intocoronary tirofiban. A 6 F thrombus aspiration catheter was used in all patients. Tirofiban was injected locally at the place of the highly thrombus burden through the aspiration device after flushing the aspiration device well.

RESULTS

Patients of intracoronary tirofiban group compared with control group had a significant difference in decreasing the infarct size at 30 days [median, 15.451 g - interquartile range (IQR), 17.404 gm - n = 50] vs (median, 43.828 g - IQR, 49.599 g - n = 50) P value = 0.002.

CONCLUSION

In patients early presented with large anterior STEMI, infarct size at 30 days was significantly decreased by intracoronary tirofiban delivered to the infarct lesion site followed aspiration thrombectomy.

Biomarker assessment for early infarct size estimation in ST-elevation myocardial infarction

BACKGROUND

High-sensitivity cardiac troponin T (hs-cTnT) represents the biomarker of choice for infarct size (IS) estimation in patients with acute ST-elevation myocardial infarction (STEMI). However, admission values of hs-cTnT are only weakly associated with IS. The aim of this study was to investigate the incremental value of different biomarkers measured on admission for IS estimation in STEMI patients.

METHODS

In this prospective observational study, we included 161 consecutive STEMI patients treated with primary percutaneous coronary intervention (pPCI). The following biomarkers were assessed on admission: hs-cTnT, N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) and neutrophil/lymphocyte ratio (NLR). IS was determined by cardiac magnetic resonance (CMR) imaging 3 (Interquartile range [IQR] 2 to 4) days after the index event.

RESULTS

Patients with large IS (>19% of left ventricular myocardium) showed significantly higher levels of admission hs-cTnT (399.6 vs. 53.4 ng/L, p < .001), NT-pro-BNP (140 vs. 86 ng/L, p = .008) and NLR (6.4 vs. 4.1, p < .001). The combination of hs-cTnT, NT-pro-BNP and NLR on admission resulted in a significantly higher area under the curve (0.78; 95% CI 0.704 to 0.838, (p = .01)) for the prediction of large IS than admission hs-cTnT alone (0.69; 95% CI 0.619 to 0.767).

CONCLUSIONS

In STEMI patients undergoing pPCI, a comprehensive biomarker approach on admission including hs-cTnT, NT-pro-BNP and NLR was significantly better for immediate infarct severity estimation as compared to hs-cTnT alone.

Predictive Value of High-Sensitivity Troponin T for Systolic Dysfunction and Infarct Size (Six Months) After ST-Elevation Myocardial Infarction

The association of markers of myocardial injury and dysfunction with infarct size (IS) and ejection fraction (EF) are well documented. However, limited data are available on the newer high-sensitivity troponin assays and comparison with morphologic and functional assessment with cardiac magnetic resonance imaging. We aimed to examine the associations of high-sensitivity cardiac Troponin-T (hs-cTnT), creatine kinase MB iso-enzyme (CKMB), and N-terminal pro B-type Natriuretic Peptide (NT-proBNP) to IS and EF at 6 months. Blood samples from 119 ST-segment elevation myocardial infarction patients from the Rapid Endovascular Catheter Core Cooling Combined With Cold Saline solution as an Adjunct to Percutaneous Coronary Intervention for the Treatment of Acute Myocardial Infarction trial were collected at baseline, 6, 24, and 48 hours after admission. Cardiac magnetic resonance was performed at 4 ± 2 days and 6 months. The association of biomarker levels to IS and EF was tested with Pearson's correlation coefficients and linear regression models with bootstrap resampling. The correlation coefficient of biomarker to IS was (CKMB: r = 0.71); (NT-proBNP: r = 0.55); (hs-cTnT: r = 0.80); and for EF (CKMB: r = 0.57); (NT-proBNP: r = 0.48); and (peak hs-cTnT: r = 0.68). IS and EF at 4 ± 2 days had the strongest correlations with IS and EF at 6 months respectively (IS: r = 0.84) and (EF: r = 0.74). Receiver operating characteristic of peak hs-cTnT for predicting EF ≤40% at 6 months was 0.87 compared with 0.75 for early IS. Early EF was a negative predictor of late EF <40%, 1-area under curve = 0.93. In conclusion, high-sensitivity Troponin T is a rapid, cheap, generally available tool for accurate prediction of systolic dysfunction in patients 6 months after first-time ST-segment elevation myocardial infarction.

Relationship between TRAIL and Left Ventricular Ejection Fraction in Patients with ST-Elevation Myocardial Infarction Treated with Primary Percutaneous Coronary Intervention

Background

Apoptosis plays an important role in the myocardial injury after acute myocardial infarction and in the subsequent development of heart failure.

Aim

To clarify serum kinetics of apoptotic markers TRAIL and sFas and their relation to left ventricular ejection fraction (LVEF) in patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI).

Methods

In 101 patients with STEMI treated with pPCI, levels of TRAIL and sFas were measured in series of serum samples obtained during hospitalization and one month after STEMI. LVEF was assessed at admission and at one month. Major adverse cardiovascular events (MACE, i.e., death, re-MI, and hospitalization for heart failure and stroke) were analysed during a two-year followup.

Results

Serum level of TRAIL significantly decreased one day after pPCI (50.5pg/mL) compared to admission (56.7pg/mL), subsequently increased on day 2 after pPCI (58.8pg/mL), and reached its highest level at one month (70.3pg/mL). TRAIL levels on days 1 and 2 showed a significant inverse correlation with troponin and a significant positive correlation with LVEF at baseline. Moreover, TRAIL correlated significantly with LVEF one month after STEMI (day 1: r=0.402, p<0.001; day 2: r=0.542, p<0.001). On the contrary, sFas level was significantly lowest at admission (5073pg/mL), increased one day after pPCI (6370pg/mL), and decreased on day 2 (5548pg/mL). Significantly highest sFas level was marked at one month (7024pg/mL). sFas failed to correlate with LVEF at baseline or at one month. Both TRAIL and sFas showed no ability to predict improvement of LVEF one month after STEMI or a 2-year MACE (represented by 3.29%).

Conclusion

In STEMI treated with pPCI, TRAIL reaches its lowest serum concentration after reperfusion. Low TRAIL level is associated with worse LVEF in the acute phase of STEMI as well as one month after STEMI. Higher TRAIL level appears to be beneficial and thus TRAIL seems to represent a protective mediator of post-AMI injury.

High-sensitivity cardiac troponin T, left ventricular function, and outcome in non-ST elevation acute coronary syndrome

BACKGROUND

Cardiac troponin (cTn) levels reflect infarct size and depressed left ventricular ejection fraction (LVEF) in patients with non-ST elevation acute coronary syndrome (NSTE-ACS). However, there is very limited information on whether cTn measured with a high-sensitivity (hs) assay would provide incremental prognostic information to the LVEF in NSTE-ACS patients.

METHODS

This was a registry-based study (SWEDEHEART registry) investigating 20,652 NSTE-ACS patients with available information on hs-cTnT (highest level recorded during the hospitalization) and the LVEF estimated using echocardiography. All patients had been followed for 1 year.

RESULTS

Hs-cTnT levels independently predicted major cardiovascular events (MACE) in cohorts with normal, slightly depressed, moderately depressed, and severely depressed LVEF. The adjusted hazard ratios in these cohorts were 1.18 (95% CI 1.13-1.23), 1.12 (95% CI 1.06-1.18), 1.12 (95% CI 1.06-1.19), and 1.21 (95% CI 1.13-1.30), respectively. Hs-cTnT levels were particularly predictive for cardiovascular mortality and readmission for heart failure. Excluding patients with previous cardiac disease did not affect the overall interrelations of hs-cTnT and LVEF with MACE.

CONCLUSIONS

Hs-cTnT levels provide incremental prognostic value independent of the LVEF in patients with NSTE-ACS. Hs-cTnT is particularly predictive for MACE in patients with severely depressed LVEF but also in those with a normal LVEF. Accordingly, a normal LVEF should not be used as an argument not to target patients to thorough workup.

Clinical predictors for the manifestation of late gadolinium enhancement after acute myocardial infarction

Despite prompt revascularization, some patients with acute myocardial infarction (AMI) develop myocardial scars, which can be visualized by late gadolinium enhancement (LGE) in cardiovascular magnetic resonance imaging (CMR). Our goal was to identify angiographic findings that were predictive for scar development in patients after reperfused AMI.We examined 136 patients after first ST-elevated myocardial infarction by CMR after a median of 4 days (range: 2-7). Patients with manifestation of LGE were matched to patients without LGE by means of age and gender. Clinical follow-up with a combined primary endpoint including myocardial reinfarction, congestive heart failure, stroke, death and development of left ventricular thrombus was reported after 24 months.Patients with manifestation of LGE had a significant longer time of symptom-to-intervention, a higher prevalence of anterior AMI, and more proximal culprit lesions. Furthermore, left ventricular ejection fraction was significantly decreased, and peak values of infarct markers were significantly higher in these patients. Preinterventional thrombolysis in myocardial infarction-0-flow was significantly more frequent in patients with LGE manifestation. The presence of 3-vessel disease (odds ratio 53.99, 95% confidence interval 8.22-354.63, P <.001), a proximal culprit lesion, and high creatine kinase myocardial band (CK-MB) values were identified as independent predictors of LGE. Follow-up demonstrated a higher incidence of clinical events in the group with LGE, with the most common cause of heart failure (38.2% vs 7.4%, P <.001).The extent of angiographic findings in AMI plays a major role in the manifestation of LGE. The presence of a multivessel disease, a proximal culprit lesion, and high values of CK-MB are strong independent predictors for LGE manifestation.

Predictors of Left Ventricle Remodeling: Combined Plasma B-type Natriuretic Peptide Decreasing Ratio and Peak Creatine Kinase-MB

Background: Previous studies reported that patients who had an acute myocardial infarction (AMI) have found that measuring B-type natriuretic peptide (BNP) during the subacute phase of left ventricular (LV) remodeling can predict the possible course of LV remodeling. This study assessed the use of serial BNP serum levels combined with early creatine kinase-MB (CK-MB) to predict the development of significant LV remodeling in AMI patients. Methods: Nighty-seven patients with new onset AMI were assessed using serial echocardiographic studies and serial measurements of BNP levels, both performed on day-2 (BNP1), day-7 (BNP2), day-90 (BNP3), and day-180 (BNP4) after admission. LV remodeling was defined as >20% increase in biplane LV end-diastolic volume on day-180 compared to baseline (day-2). Results: Patients were divided into LV remodeling [LVR(+)] and non LV remodeling [LVR(-)] groups. No first-week BNP level was found to predict remodeling. However, the two groups had significantly different day-90 BNP level (208.1 ± 263.7 pg/ml vs. 82.4 ± 153.7 pg/ml, P = 0.039) and significantly different 3-month BNP decrease ratios ( R BNP₁₃) (14.4 ± 92.2% vs. 69.4 ± 25.9%, P < 0.001). The appropriate cut-off value for R BNP₁₃ was 53.2% (AUC = 0.764, P < 0.001). Early peak CK-MB (cut-off 48.2 ng/ml; AUC = 0.672; P = 0.014) was another independent predictor of remodeling. Additionally, combining peak CK-MB and R BNP₁₃ offered an excellent discrimination for half-year remodeling when assessed by ROC curve (AUC = 0.818, P < 0.001). Conclusion: R BNP₁₃ is a significant independent predictor of 6-month LV remodeling. The early peak CK-MB additionally offered an incremental power to the predictions derived from serial BNP examinations.

The contemporary value of peak creatine kinase-MB after ST-segment elevation myocardial infarction above other clinical and angiographic characteristics in predicting infarct size, left ventricular ejection fraction, and mortality

BACKGROUND

Complex multimarker approaches to predict outcome after ST-elevation myocardial infarction (STEMI) have only considered a single baseline sample, while neglecting easily obtainable peak creatine kinase and creatine kinase-MB (CK-MB) values during hospitalization.

METHODS

We studied 476 patients undergoing primary percutaneous coronary intervention for STEMI and cardiac magnetic resonance imaging (CMRI) at 4-6 months after STEMI. We determined the association with cardiac biomarkers (peak CK-MB, peak troponin T, N-terminal pro-brain natriuretic peptide), clinical and angiographic characteristics with infarct size, and LVEF, followed by association with mortality in 1120 STEMI patients.

RESULTS

Peak CK-MB was the strongest predictor for infarct size (P<0.001, R ² =0.60) and LVEF (P<0.001, R ² =0.40). The additional value of clinical and angiographic characteristics was limited. The optimal peak CK-MB cutpoints, for differentiation among small (<10% of the left ventricle), moderate (≥10%-<30%), and large infarct size (≥30%), were 210 U/L and 380 U/L, respectively. These cutpoints were associated with 90-day mortality; the hazard ratio for moderate infarct was 2.99 (95% confidence interval [CI]: 1.51-5.93, P=0.002) and for large infarct 6.53 (95% CI: 3.63-11.76, P<0.001).

CONCLUSIONS

Classical peak CK-MB measured during hospitalization for STEMI was superior to other clinical and angiographic characteristics in predicting CMRI-defined infarct size and LVEF, and should be included and validated in future multimarker studies. Peak CK-MB cutpoints differentiated among infarct size categories and were associated with increased 90-day mortality risk.

Novel biomarkers predicting cardiac function after acute myocardial infarction

BACKGROUND

Measurement of biomarkers provides a cost-effective and widely available method to estimate cardiac dysfunction and clinical outcome of patients with acute myocardial infarction (AMI).

SOURCES OF DATA

PubMed entries with terms 'myocardial infarction' and the respective biomarker.

AREAS OF AGREEMENT

Cardiac troponins and natriuretic peptides are closely related to left ventricular dysfunction and the occurrence of adverse clinical events following AMI.

AREAS OF CONTENTION

The incremental value of novel biomarkers is controversial.

FUTURE DIRECTIONS

The combination of traditional and novel biomarkers might further improve risk stratification of patients with AMI.

SEARCH STRATEGY

We searched all entries on the PubMed database with the MeSH terms 'myocardial infarction' and 'cardiac troponins', 'natriuretic peptides', 'copeptin', galectin-3', 'corin', 'fetuin-A', 'adiponectin' and 'microRNA'.

Identification of High-Risk Patients with Non-ST Segment Elevation Myocardial Infarction using Strain Doppler Echocardiography: Correlation with Cardiac Magnetic Resonance Imaging

Assessment of left ventricular (LV) function is important for decision-making and risk stratification in patients with acute coronary syndrome. Many patients with non-ST segment elevation myocardial infarction (NSTEMI) have substantial infarction, but these patients often do not reveal clinical signs of instability, and they rarely fulfill criteria for acute revascularization therapy.

AIM

This study evaluated the potential of strain Doppler echocardiography analysis for the assessment of LV infarct size when compared with standard two-dimensional echo and cardiac magnetic resonance (CMR) data.

METHODS

Thirty patients with NSTEMI were examined using echocardiography after hospitalization for 1.8 ± 1.1 days for the assessment of left ventricular ejection fraction, wall motion score index (WMSI), and LV global longitudinal strain (GLS). Infarct size was assessed using delayed enhancement CMR 6.97 ± 3.2 days after admission as a percentage of total myocardial volume.

RESULTS

GLS was performed in 30 patients, and 82.9% of the LV segments were accepted for GLS analysis. Comparisons between patients with a complete set of GLS and standard echo, GLS and CMR were performed. The linear relationship demonstrated moderately strong and significant associations between GLS and ejection fraction (EF) as determined using standard echo (r = 0.452, P = 0.012), WMSI (r = 0.462, P = 0.010), and the gold standard CMR-determined EF (r = 0.57, P < 0.001). Receiver operating characteristic curves were used to analyze the ability of GLS to evaluate infarct size. GLS was the best predictor of infarct size in a multivariate linear regression analysis (β = 1.51, P = 0.027). WMSI >1.125 and a GLS cutoff value of -11.29% identified patients with substantial infarction (≥12% of total myocardial volume measured using CMR) with accuracies of 76.7% and 80%, respectively. However, GLS remained the only independent predictor in a multivariate logistic regression analysis to identify an infarct size ≥12%.

CONCLUSION

GLS is a good predictor of infarct size in NSTEMI, and it may serve as a tool in conjunction with risk stratification scores for the selection of high-risk NSTEMI patients.

Prognostic value of high sensitivity troponin T after ST-segment elevation myocardial infarction in the era of cardiac magnetic resonance imaging

Aims

To determine if high sensitivity troponin T (hs-TnT) measurements performed during the 'plateau phase' of troponin release (≥48 h) following ST-segment elevation myocardial infarction (STEMI) can predict major adverse cardiovascular endpoints (MACE), and to evaluate its prognostic value compared with cardiac magnetic resonance imaging (CMRI) parameters.

Methods and results

We prospectively recruited 201 first presentation STEMI patients. Serial hs-TnT levels were measured at admission, peak (highest), 24, 48 and 72 h. CMRI and transthoracic echocardiography were performed (4 days median) post-STEMI, evaluating infarct scar characteristics and left ventricular ejection fraction (LVEF). Associations were determined between hs-TnT levels and CMRI parameters early after STEMI with MACE (comprising mortality, re-infarction, new or worsening of heart failure, cerebrovascular accident, and sustained ventricular arrhythmias) at medium-term follow-up. After 602 days (median), 33 (17%) patients had MACE. Upper tertile hs-TnT levels at 48 and 72 h were associated with MACE (Kaplan-Meier P = 0.002 and P = 0.012, respectively). Multivariate Cox analyses, incorporating diabetes, CMRI scar size, LVEF and hs-TnT levels (applied at a single hs-TnT time point) showed that 48 and 72 h hs-TnT levels were independent predictors for MACE (HR = 1.20, P = 0.002, and HR = 1.21, P = 0.035 respectively).

Conclusion

Measurement of hs-TnT in the plateau phase after STEMI is an inexpensive method of prognostic risk assessment.

High-sensitivity troponin T predicts infarct scar characteristics and adverse left ventricular function by cardiac magnetic resonance imaging early after reperfused acute myocardial infarction

BACKGROUND

Late gadolinium enhancement cardiac magnetic resonance imaging (CMRI) is the current standard for evaluation of myocardial infarct scar size and characteristics. Because post-ST-segment elevation myocardial infarction (STEMI) troponin levels correlate with clinical outcomes, we sought to determine the sampling period for high-sensitivity troponin T (hs-TnT) that would best predict CMRI-measured infarct scar characteristics and left ventricular (LV) function.

METHODS AND RESULTS

Among 201 patients with first presentation with STEMI who were prospectively recruited, we measured serial hs-TnT levels at admission, peak, 24 hours, 48 hours, and 72 hours after STEMI. Indexed LV volumes, LV ejection fraction (LVEF) and infarct scar characteristics (scar size, scar heterogeneity, myocardial salvage index, and microvascular obstruction) were evaluated by CMRI at a median of 4 days post-STEMI. Peak and serial hs-TnT levels correlated positively with early indexed LV volumes and infarct scar characteristics, and negatively correlated with myocardial salvage index and LVEF. Both 48- and 72-hour hs-TnT levels similarly predicted "large" total infarct scar size (odds ratios [ORs] 3.08 and 3.53, both P < .001), myocardial salvage index (ORs 1.68 and 2.30, both P < .001), and LVEF <40% (ORs 2.16 and 2.17, both P < .001) on univariate analyses. On multivariate analyses, 48- and 72-hour hs-TnT levels independently predicted large infarct scar size (ORs 2.05 and 2.31, both P < .001), reduced myocardial salvage index (OR 1.39 [P = .031] and OR 1.55 [P = .009]), and LVEF <40% (OR 1.47 [P = .018] and OR 1.43 [P = .026]). All measured hs-TnT levels had a modest association and similar capacity to predict microvascular obstruction.

CONCLUSIONS

Levels of hs-TnT at 48 and 72 hours, measured during the "plateau phase" post-STEMI, predicted infarct scar size, poor myocardial salvage, and LVEF. These levels also correlated with scar heterogeneity and microvascular obstruction post-STEMI. Since ascertaining peak levels after STEMI is challenging in routine practice, based on the biphasic kinetics of hs-TnT, a measurement at 48 to 72 hours (during the plateau phase) provides a useful and simple method for early evaluation of LV function and infarct scar characteristics.

High-sensitivity troponin T for prediction of left ventricular function and infarct size one year following ST-elevation myocardial infarction

BACKGROUND

Data relating high-sensitivity cardiac troponin T (hs-cTnT) to long-term myocardial function and infarct size in patients after ST-elevation myocardial infarction (STEMI) are lacking. We aimed to evaluate the use of early hs-cTnT concentrations for prediction of myocardial function and infarct size assessed by cardiac magnetic resonance imaging (CMR) one year following STEMI.

METHODS

Sixty-six patients, revascularized by primary percutaneous coronary intervention (PCI) for first-time STEMI, were enrolled in this observational study. Serial hs-cTnT, creatine kinase (CK), high-sensitivity C-reactive protein (hs-CRP) and lactate dehydrogenase (LDH) levels were measured on admission, 6 h, 12 h, and 24 h post-PCI. Patients underwent CMR within the first week and 12months thereafter.

RESULTS

Except for admission hs-cTnT, all single time point and peak hs-cTnT concentrations showed significant correlations with left ventricular ejection fraction (LVEF: r=-0.404 to -0.517, all ps<0.01) and infarct size (IS: r=0.421 to 0.700, all ps<0.01) at baseline and follow-up. The area under the curve (AUC) of peak hs-cTnT was 0.82 (95% CI 0.71-0.92) for the prediction of decreased LVEF (<55%) and 0.89 (95% CI 0.81-0.97) for the prediction of large IS (>8%) at 12months. The combination of all four biomarkers resulted in an AUC of 0.82 and 0.92 for the prediction of reduced LVEF and large IS at 12months, respectively (both ps>0.05).

CONCLUSION

In stable STEMI patients successfully revascularized by primary PCI, serial and peak concentrations of hs-cTnT are closely correlated to long-term LVEF and IS. Combination of hs-cTnT with CK, hs-CRP, or LDH did not add any significant prognostic value as compared with hs-cTnT alone.

Thrombus aspiration for reperfusion in myocardial infarction: Predictors and clinical impact of ineffectiveness

INTRODUCTION AND OBJECTIVES

The benefit of manual thrombus aspiration (TA) in the reperfusion of patients with ST-elevation myocardial infarction (STEMI) has been hotly debated. In most series, failure of TA has been largely unreported. Our objectives were to assess the rate, predictors, and impact on cumulative mortality of failed TA during primary percutaneous coronary intervention (PPCI).

METHODS

This was a single-center, retrospective study of consecutive STEMI patients undergoing PPCI with TA. TA was considered ineffective if, before angioplasty, coronary flow was TIMI <2. Independent predictors of TA failure were assessed by logistic regression, and predictors of cumulative mortality were assessed by Cox regression analysis.

RESULTS

Of 574 patients, TA was used in 417 (72.6%), and was effective in 365 (87.5%) and ineffective in 52 (12.5%). On multivariate analysis, SYNTAX score (OR=1.049, 95% CI: 1.015-1.084, p=0.005) and total ischemic time (OR=1.001, 95% CI: 1.000-1.003, p=0.02) were independent predictors of TA failure. Moderate or severe left ventricular dysfunction (HR=6.256, 95% CI: 1.896-20.644, p=0.003), APPROACH score (HR=1.094, 95% CI: 1.016-1.177, p=0.017), Killip class III/IV (HR=2.953, 95% CI: 1.122-7.770, p=0.028) and creatinine clearance on admission (HR=0.973, 95% CI: 0.953-0.994, p=0.011) were independently related to cumulative mortality at 24 ± 0.82 months.

CONCLUSIONS

Total ischemic time and SYNTAX score were independent predictors of TA failure. However, in medium-term follow-up, ineffective manual TA was not independently related to cumulative mortality.

Effects of N-acetylcysteine on the cardiac remodeling biomarkers and major adverse events following acute myocardial infarction: a randomized clinical trial

AIMS

The aims of this study were to evaluate the effects of N-acetylcysteine (NAC) on cardiac remodeling and major adverse events following acute myocardial infarction (AMI).

METHODS

In a prospective, double-blind, randomized clinical trial, the effect of NAC on the serum levels of cardiac biomarkers was compared with that of placebo in 98 patients with AMI. Also, the patients were followed up for a 1-year period for major adverse cardiac events (MACE), including the occurrence of recurrent myocardial infarction, death, and need for target vessel revascularization.

RESULTS

In patients who received NAC, the serum levels of matrix metalloproteinase (MMP)-9 and MMP-2 after 72 h were significantly lower than those in the placebo group (p = 0.014 and p = 0.045, respectively). The length of hospitalization in patients who received NAC was significantly shorter than that in the placebo group (p = 0.024). With respect to MACE, there was a significant difference between those who received NAC (14 %) and those patients on placebo (25 %) (p = 0.024). Re-infarction took place in 4 % of patients in the NAC group as compared with 16.7 % in patients who received placebo (p = 0.007).

CONCLUSION

NAC can be beneficial in preventing early remodeling by reducing the level of MMP-2 and MMP-9. Moreover, NAC decreased the length of hospital stays in patients after AMI. By decreasing MACE, NAC could possibly be introduced as a 'magic bullet' in the pharmacotherapy of patients with AMI. Further studies are needed to elucidate NAC's role in this population.

Assessing myocardial recovery following ST-segment elevation myocardial infarction: short- and long-term perspectives using cardiovascular magnetic resonance

Myocardial recovery after revascularization for ST-segment elevation myocardial infarction (STEMI) remains a significant diagnostic and, despite novel treatment strategies, a therapeutic challenge. Cardiovascular magnetic resonance (CMR) has emerged as a valuable clinical and research tool after acute STEMI. It represents the gold standard for functional and morphological evaluation of the left ventricle. Gadolinium-based perfusion and late-enhancement viability imaging has expanded our knowledge about the underlying pathologies of inadequate myocardial recovery. T2-weighted imaging of myocardial salvage after early reperfusion of the infarct-related artery underlines the effectiveness of current invasive treatment for STEMI. In the last decade, the number of publications on CMR after acute STEMI continued to rise, with no plateau in sight. Currently, CMR research is gathering robust prognostic data on standardized CMR protocols with the aim to substantially improve patient care and prognosis. Beyond established CMR protocols, more specific methods such as magnetic resonance relaxometry, myocardial tagging, 4D phase-contrast imaging and novel superparamagnetic contrast agents are emerging. This review will discuss the currently available data on the use of CMR after acute STEMI and take a brief look at developing new methods currently under investigation.

Association of copeptin with myocardial infarct size and myocardial function after ST segment elevation myocardial infarction

OBJECTIVE

To investigate the relationship between circulating plasma copeptin values and infarct size as well as myocardial function at baseline and 4 months after mechanical reperfusion for ST segment elevation myocardial infarction (STEMI).

DESIGN

Prospective observational cohort study.

SETTING

University Hospital of Innsbruck.

PATIENTS

54 patients with acute STEMI.

MAIN OUTCOME MEASURES

Correlation of plasma copeptin with infarct size as well as left ventricular ejection fraction (LVEF) and remodelling.

METHODS

Participants underwent contrast enhanced cardiac MRI at baseline and 4 months thereafter. Blood samples were drawn 2 days after the onset of symptoms. Copeptin values were determined by an immunofluorescent assay.

RESULTS

Copeptin concentrations (median 10.4 pmol/l, IQR 6.0-14.4) were associated with early and chronic infarct size (r=0.388, p=0.004 at baseline; r=0.385, p=0.011 at follow-up) and inversely related to LVEF at both times (r=-0.484, p<0.001 at baseline; r=-0.461, p<0.001 at follow-up). Patients with adverse remodelling showed higher baseline copeptin values compared to patients without remodelling (p=0.02). Receiver operating characteristic analysis indicated a cut-off value of 16.7 pmol/l for copeptin to best identify patients with future adverse remodelling.

CONCLUSIONS

Increased copeptin values 2 days after STEMI are associated with larger acute and chronic infarct sizes. Moreover, elevated copeptin concentrations at baseline were associated with myocardial function and remodelling 4 months post-STEMI. These findings strengthen the role of copeptin as a biomarker of adverse outcome after STEMI.

Peak and fixed-time high-sensitive troponin for prediction of infarct size, impaired left ventricular function, and adverse outcomes in patients with first ST-segment elevation myocardial infarction receiving percutaneous coronary intervention

The clinical use of advanced imaging modalities for early determination of infarct size and prognosis is limited. As a specific indicator of myocardial necrosis, cardiac troponin T (cTnT) can be used as a surrogate measure for this purpose. The present study sought to investigate the use of peak and serial 6-hour fixed-time high-sensitive (hs) cTnT for estimation of infarct size, left ventricular (LV) function, and prognosis in consecutive patients with ST-segment elevation myocardial infarction. The infarct size was expressed as the 48-hour cumulative creatine kinase release. LV function at 3 months was assessed using the echocardiographic wall motion score index and LV ejection fraction using radionuclide ventriculography. Adverse outcomes, comprising all-cause death, implantable cardioverter-defibrillator implantation, or hospitalization for heart failure, were recorded at 1 year of follow-up. In 188 patients, the peak and all fixed-time values correlated significantly with the 48-hour cumulative creatine kinase release, wall motion score index, and LV ejection fraction. The hs-cTnT value at 24 hours demonstrated the greatest correlation (r = 0.86, r = 0.47, and r = -0.59, respectively; p <0.001 for all). In the multivariate regression models adjusted for the clinical parameters, almost all were independently associated with the 48-hour cumulative creatine kinase release, wall motion score index, and LV ejection fraction, with the hs-cTnT value at 24 hours having the largest effect. Moreover, all cTnT values independently predicted adverse outcomes, again, with the hs-cTnT value at 24 hours showing the largest influence (hazard ratio 3.77, 95% confidence interval 2.12 to 6.73, p <0.001). In conclusion, not only peak, but all fixed-time hs-cTnT values were associated with infarct size, LV function at 3 months, and adverse outcomes 1 year after ST-segment elevation myocardial infarction. The value 24 hours after the onset of symptoms had the closest associations with all outcomes. Therefore, serial sampling for a peak value might be redundant.

Obstructive sleep apnea and acute myocardial infarction severity: ischemic preconditioning?

BACKGROUND

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxia (IH). In animal models, IH has been shown to protect the myocardium during periods of ischemia by reducing infarct size. However, this phenomenon of "ischemic preconditioning" has not been investigated among OSA patients with acute myocardial infarction (MI). This study investigates the role of OSA on MI severity as measured by cardiac enzymes, specifically troponin-T, among patients with an acute MI.

METHODS

This is an observational cohort study of patients ≥18 years of age who were hospitalized with an acute MI. Each participant underwent portable sleep monitoring (Apnea Link Plus); OSA was defined as an apnea-hypopnea index ≥5/h. Multivariable regression analysis was conducted to assess the relationship between OSA and highly sensitive troponin-T levels.

RESULTS

In our entire cohort of acute MI patients (n = 136), 77 % of the sample had evidence of sleep disordered breathing, with 35 % of the sample having OSA (i.e., an AHI >5). Higher AHI was associated with lower peak troponin-T levels in partially adjusted models (β = -0.0320, p = 0.0074, adjusted for age, gender, and race) and fully adjusted models (β = -0.0322, p = 0.0085) (additionally adjusted for smoking, hypertension, hyperlipidemia, body mass index, history of prior cardiovascular or cerebrovascular disease, diabetes and baseline admission creatinine levels). The mean value of the log-transformed peak troponin-T variable was used to dichotomize the outcome variable. In both partially (OR 0.949, CI 0.905-0.995, p = 0.03) and fully adjusted (OR 0.918, CI 0.856-0.984, p = 0.0151) logistic regression models, the OR for AHI suggests a protective effect on high troponin-T level.

CONCLUSIONS

Our study demonstrates that patients with OSA have less severe cardiac injury during an acute non-fatal MI when compared to patients without OSA. This may suggest a cardioprotective role of sleep apnea during acute MI via ischemic preconditioning.