Enzyme estimates of infarct size correlate with functional and clinical outcomes in the setting of ST-segment elevation myocardial infarction

Body fat percentage and infarct size in patients with non-ST segment elevation myocardial infarction

OBJECTIVE

Obesity is a global health problem that increases the risk of coronary artery disease (CAD). However in studies, it has been observed that when the disease develops, obese patients have a more favorable prognosis than leaner patients. This is called the "obesity paradox." This study aims to evaluate the effect of obesity assessed with body fat percentage (BFP) and relative fat mass (RFM) besides body mass index (BMI) on infarct size (IS) estimated from peak creatine kinase-MB (CK-MB) levels in patients with non-ST-segment elevation myocardial infarction (NSTEMI).

METHODS

Patients with a diagnosis of NSTEMI who underwent coronary angiography between January 2017 and January 2022 were retrospectively evaluated. Patients without available anthropometric data to calculate BMI, BFP, and RFM and serial CK-MB measurements were excluded from the study. BMI was calculated using weight(kg)/(height[m])2 formula. Patients were dichotomized as obese (BMI≥30 kg/m2) and non-obese (BMI<30 kg/m2) to compare baseline characteristics. BFP and RFM were calculated from anthropometric data. Linear regression analysis was performed to define predictors of IS.

RESULTS

Final study population consisted of 748 NSTEMI patients (mean age was 59.3±11.2 years, 76.3% were men, 36.1% of the patients were obese). Obese patients were more likely to be female, hypertensive, and diabetic. Smoking was less frequently observed in obese patients. Peak CK-MB levels were similar among groups. Obese patients had higher in-hospital left ventricular ejection fraction, and less severe CAD was observed in coronary angiographies of these patients. Multivariable regression analysis identified diabetes mellitus, systolic blood pressure, white blood cell count, hemoglobin, and BFP (β=-4.8, 95% CI=-8.7; -0.3, p=0.03) as independent predictors of IS.

CONCLUSION

Higher BFP is associated with smaller IS in NSTEMI patients. These findings support the obesity paradox in this patient group, but further, randomized controlled studies are required.

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.

Association between admission ECG changes and long-term mortality in patients with an incidental myocardial infarction: Results from the KORA myocardial infarction registry

BACKGROUND

The aim of this study was to examine the predictive value of specific changes in admission ECG on long-term outcome in acute myocardial infarction (AMI).

METHODS

From 2000 until 2017 all AMI cases (n = 9,689) in the study area of Augsburg, Germany, were prospectively recorded. For this study, all patients with a first-time AMI, who survived the first 28 days, were considered. Median observational time was 6.7 years (IQR: 3.6-10.9). Each case was assigned to one of the following groups according to the admission ECG: 'ST-segment elevation', 'ST-segment depression', 'T-wave inversion', 'unspecific changes', 'normal ECG' and 'bundle branch block' (BBB). Multivariable adjusted COX regression models were calculated to compare long-term all-cause mortality.

RESULTS

The final regression model revealed a significantly higher mortality among patients with BBB (HR: 1.52 [1.34-1.73], p-value: < 0.001) and 'ST-segment depression' (HR: 1.16 [1.03-1.29], p-value: 0.01252) compared to the STEMI group (reference group). The 'normal ECG' group (HR: 0.76 [0.66-0.87], p-value: < 0.001) on the other hand was associated with significantly lower long-term mortality. The 'T-wave inversion' group (HR: 1.08 [0.96-1.21]) and the 'unspecific changes' group (HR: 1.05 [0.94-1.17]) did not differ significantly from the STEMI group.

CONCLUSION

ST-segment depressions and BBB admission ECGs go along with higher long-term mortality in AMI patients compared to STEMI cases. This should be taken into account by physicians when treating patients with NSTEMIs. Only the complete absence of AMI-related ECG changes predicts a more favorable outcome.

Platelet Reactivity Was Not Associated with Infarct Size after Primary Percutaneous Coronary Intervention

Potent antiplatelet therapy after primary percutaneous coronary intervention (PCI) has the potential to reduce infarct size. This study analyzed the association between on-treatment platelet reactivity and myocardial infarct size in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI. In this single-center, retrospective study, 253 patients who underwent primary PCI for STEMI were divided into two groups according to platelet reactivity measurements (53 patients in the high platelet reactivity [HPR] group and 200 in the non-HPR group). Technetium Tc-99m tetrofosmin single-photon emission computed tomography (SPECT) was performed before hospital discharge. We measured the infarct size using SPECT imaging and serial cardiac biomarker levels, and compared the infarct sizes of each group. The patients with HPR were older (65.5±13.2 vs. 60.6±12.1 years, p=0.011) than the patients with non-HPR. On the other hand, the non-HPR group had a higher incidence of smoking (26.4% vs. 51.0%, p=0.001) than the HPR group. Infarct size was similar between the two groups (22.6±17.3% vs. 24.8±17.7%, p=0.416). Multivariate analysis revealed that onset to balloon time >240 min (odds ratio [OR]=1.92; 95% confidence interval [CI]=1.08-3.40; p=0.025) and anterior infarction (OR=5.28; 95% CI=3.05-9.14; p<0.001) were independent predictors of large (>22%) infarct size. HPR was not a predictor of infarct size assessed by SPECT. The two groups also showed analogous cumulative creatinine kinase-myocardial band and troponin T levels. In conclusion, compared to non-HPR, HPR showed no significant association with myocardial infarct size measured by SPECT imaging in early phase of MI.

CCN family member 1 (CCN1) is an early marker of infarct size and left ventricular dysfunction in STEMI patients

BACKGROUND AND AIMS

CCN family member 1 (CCN1) has recently been proposed as a novel biomarker of myocardial injury, improving prediction of 30-day and one-year mortality following acute coronary syndromes. Among ST-elevation myocardial infarction (STEMI) patients, we evaluated the utility of CCN1 measured immediately before primary percutaneous coronary intervention (PPCI) as a predictor of two earlier endpoints: final myocardial infarct size and post-infarction left ventricular ejection fraction (LVEF). Furthermore, we evaluated the impact of CCN1 on the discriminatory power of the CADILLAC score.

METHODS

STEMI patients were obtained from the SPUM-ACS cohort. Serum CCN1 was measured prior to PPCI. Linear regression assessed the association between CCN1, peak creatinine kinase (CK), and post-infarction LVEF. Cox models assessed an association between CCN1 and 30-day all-cause mortality.

RESULTS

CCN1 was measured in 989 patients with a median value of 706.2 ng/l (IQR 434.3-1319.6). A significant correlation between CCN1, myocardial infarct size (peak CK) and LVEF was observed in univariate and multivariate analysis (both p < 0.001). Even among patients with normal classical cardiac biomarker levels at the time of PPCI, CCN1 correlated significantly with final infarct size. CCN1 significantly improved prediction of 30-day all-cause mortality by the CADILLAC score (C-index 0.864, likelihood-ratio chi-square test statistic 6.331, p = 0.012; IDI 0.026, p= 0.050).

CONCLUSIONS

Compared with classical cardiac biomarkers, CCN1 is potentially the earliest predictor of final myocardial infarct size and post-infarction LVEF. CCN1 improved the discriminatory capacity of the CADILLAC score suggesting a potential role in the very-early risk stratification of STEMI patients.

Prognostic value of the C-reactive protein to albumin ratio in patients undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction

Background/aim

This study investigated whether baseline serum level of C-reactive protein (CRP)/albumin ratio is associated with infarct localization, number of vascular lesions, and in-hospital mortality in patients undergoing primary percutaneous coronary intervention (PCI) for acute ST elevation myocardial infarction (STEMI).

Methods

The study population consisted of 116 patients diagnosed with STEMI. The CRP/albumin ratio at first admission, cardiac troponin-I (cTnI), PCI results, and clinical outcomes were recorded.

Results

The mean CRP/albumin ratio, cTnI level, and mean number of vascular lesions were significantly higher in non-survivors than in survivors (p = 0.006, p = 0.004, and p = 0.007, respectively). Multivariate logistic regression analysis demonstrated that the CRP/ albumin ratio and number of coronary artery lesions were independent predictors of mortality in STEMI patients. According to these analyses, the presence of ≥ 2 vessel lesions was the most important predictor of mortality, with an odds ratio of 2.009 (95% confidence interval: 1.191–3.387, p = 0.009).

Conclusion

This study demonstrates the potential utility of the CRP/albumin ratio for predicting the clinical outcome of patients with STEMI. In addition, the presence of ≥ 2 vascular lesions contributed to a 2-fold increase in mortality rate in STEMI patients.

Admission ECG changes predict short term-mortality after acute myocardial infarction less reliable in patients with diabetes

Prior studies examined association between short-term mortality and certain changes in the admission ECG in acute myocardial infarction (AMI). Nevertheless, little is known about possible differences between patients with diabetes and without diabetes in this regard. So the aim of the study was to investigate the association between 28-day case fatality according to certain ECG changes comparing AMI cases with and without diabetes from the general population. From 2000 until 2017 a total of 9756 AMI cases was prospectively recorded in the study Area of Augsburg, Germany. Each case was assigned to one of the following groups according to admission ECG: ‘ST-elevation’, ‘ST-depression’, ‘only T-negativity’, ‘predominantly bundle branch block’, ‘unspecific changes’ and ‘normal ECG’ (the last two were put together for regression analyses). Multivariable adjusted logistic regression models were calculated to compare 28-day case-fatality between the ECG groups for the total sample and separately for diabetes and non-diabetes cases. For the non-diabetes group, the parsimonious logistic regression model revealed significantly better 28-day-outcome for the ‘normal ECG / unspecific changes’ group (OR: 0.47 [0.29–0.76]) compared to the reference group (STEMI). Contrary, in AMI cases with diabetes the category ‘normal ECG / unspecific changes’ was not significantly associated with lower short-term mortality (OR: 0.87 [0.49–1.54]). Neither of the other ECG groups was significantly associated with 28-day-mortality in the parsimonious logistic regression models. Consequently, the absence of AMI-typical changes in the admission ECG predicts favorable short-term mortality only in non-diabetic cases, but not so in patients with diabetes.

Metformin attenuates ischemia/reperfusion-induced apoptosis of cardiac cells by downregulation of p53/microRNA-34a via activation of SIRT1

Metformin has been demonstrated to be beneficial for the treatment of an impaired myocardium as a result of ischemia/reperfusion (I/R) injury, and miR-34a may be involved in this process. The aim of the present study was to determine the mechanisms by which metformin attenuated myocardial I/R injury-induced apoptosis. In the in vivo I/R model using Sprague-Dawley rats, metformin reduced the area of damaged myocardium and serum creatine MB isoform (CKMB) activity resulting in protection of the myocardium. Metformin also reduced apoptosis and the expression of apoptosis associated proteins, including caspase 3 and cleaved caspase, and decreased the expression of miR-34a, which is upregulated during I/R injury, which in turn resulted in corresponding changes in expression of Bcl-2, a direct target of miR-34a both in vitro and in vivo. To further examine the role of miR-34a in this process, H9C2 cells were transfected by a miR-34a mimic and inhibitor. Overexpression of miR-34a increased apoptosis in H9C2 cells induced by oxygen-glucose deprivation/recovery and knockdown of miR-34a expression-reduced apoptosis under the same conditions. Therefore, the effect of metformin on miR-34a in vitro were assessed. Metformin decreased the deacetylation activity of silent information regulator 1 resulting in reduced Ac-p53 levels, which reduced the levels of pri-miR-34a, and thus in turn reduced miR-34a levels. To confirm these results clinically, 90 patients with ST-segment elevation myocardial infarction following percutaneous coronary intervention were recruited. Patients who took metformin regularly before infarction had lower miR-34a levels and lower serum CKMB activity. Metformin also improved the sum ST-segment recovery following I/R injury. In conclusion, metformin may be helpful in the treatment of myocardial I/R.

Efficacy and Safety of Abbreviated Eptifibatide Treatment in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

The glycoprotein IIb/IIIa inhibitor eptifibatide, administered as bolus followed by infusion, is an adjunctive antithrombotic treatment during primary percutaneous coronary intervention (PCI) in selected patients with ST-segment elevation myocardial infarction (STEMI). Whether both bolus and infusion are necessary to improve outcomes is unknown. We hypothesized that primary PCI with eptifibatide bolus only is non-inferior to the conventional treatment (bolus and infusion) with regard to infarct size, while reducing bleeding complications. We analyzed 720 consecutive STEMI patients receiving eptifibatide bolus only or conventional treatment in an observational case-control study utilizing propensity score matching of clinical and intervention-specific confounders. Infarct size was estimated based on myocardial bound creatine kinase, creatine kinase (CK), and CK area under the curve values, with a prespecified non-inferiority margin of 20%. Major bleeding was defined as type 2, 3, or 5 on the Bleeding Academic Research Consortium classification. Eptifibatide bolus only was administered to 147 patients (20%), which were matched 1:1 to patients receiving conventional treatment. Based on peak myocardial bound creatine kinase, CK and CK area under the curve values, infarct size was -8.4% (95% CI [-31.2%, 14.4%]), -11.6% (95% CI [-33.5%, 10.3%]), and -13.9% (95% CI [-34.1%, 6.2%]) after eptifibatide bolus, respectively, reaching prespecified noninferiority compared with conventional treatment. Bolus treatment significantly reduced major bleeding complications (OR 0.48, 95% CI [0.30, 0.79]). In conclusion, eptifibatide given as abbreviated bolus only to selected STEMI patients who underwent primary PCI was noninferior regarding infarct size and resulted in less bleeding complications compared with conventional bolus and infusion treatment.

Copeptin levels predict left ventricular systolic function in STEMI patients: A 2D speckle tracking echocardiography-based prospective observational study

In the present study, we aimed to investigate whether copeptin values on admission are related to left ventricle (LV) systolic function and its improvement at 6 months in ST-segment elevation myocardial infarction (STEMI) patients.In this single-center, prospective observational study, we included 122 STEMI patients from January 2016 to November 2016. LV systolic functions in the form of global longitudinal strain (GLS) in addition to conventional echocardiography parameters were evaluated on admission and at 6-month. Serum copeptin levels were determined using an ultrasensitive immunofluorescence assay.The study population was divided into 2 groups according to median values of copeptin. GLS was significantly lower in patients with high copeptin levels compared to those with low copeptin levels at early stage and 6-month (-16% (16-16.5) vs -15% (15-15.5), P < .001 and -18% (18-19) vs -16% (16-16.25), P < .001, respectively). Copeptin values were negatively correlated with an early and 6-month GLS (r = -0.459 at early stage and r = -0.662 at 6-month). In addition, we observed that copeptin values were negatively correlated with the improvement of GLS at 6-month follow-up (r = -0.458, P < .001 and r = -0.357, P = .005, respectively).Serum copeptin levels in STEMI patients at the time of admission may predict early and 6-month LV systolic function assessed by two-dimensional GLS. To the best of our knowledge, this study is the first to specifically address the relationship between copeptin values and GLS in STEMI patients.

Association of influenza infection and vaccination with cardiac biomarkers and left ventricular ejection fraction in patients with acute myocardial infarction

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We examined the association of influenza infection and vaccination with cardiac biomarkers and LVEF .

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Mean and median CK-MB levels were significantly higher among unvaccinated cases .

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Large size infarcts were more frequent in influenza positive cases and less frequent in vaccinated cases.

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Influenza vaccine may have a protective effect against large infarcts .

Aims

The aim of this study was to examine the association of influenza infection and vaccination with extent of cardiac damage during acute myocardial infarctions (AMIs) as measured by serum biomarkers and left ventricular ejection function (LVEF) in patients.

Methods

Post-hoc analysis was performed on data from a prospective case-control study of influenza and AMI, conducted in a tertiary care hospital in Sydney, Australia. We included 275 cases of AMI, aged ≥ 40 years admitted to the cardiology during the study period.

Results

Mean and median CK-MB levels were significantly higher among unvaccinated group compared to vaccinated group (p value < 0.05). Troponin levels were also higher among unvaccinated group compared to vaccinated group; although not statistically significant. Troponin and CKMB values were not statistically different among influenza positive cases and influenza negative cases. Large size infarcts were less frequent among vaccinated cases compared to unvaccinated cases (25% vs 35.5%) and were more frequent among influenza positive cases compared to influenza negative cases (35.3% vs 31.5%), however differences were not statistically significant. LVEF was lower among vaccinated cases compared to unvaccinated cases (62.5% vs. 52.8%) and influenza positive cases compared to influenza negative cases (58.8% vs 55.4), however differences were not significant.

Conclusion

Lower CKMB levels among vaccinated groups showed that influenza vaccine may have a protective effect against large infarcts, therefore influenza vaccination should be recommended for high risk groups. The study suggests an association of larger infarcts with influenza infection, but larger studies are required to confirm this.

Stress hyperglycemia: A prospective study examining the relationship between glucose, cortisol and diabetes in myocardial infarction

AIM

We aimed to explore the relationship between stress, hyperglycemia and diabetes in myocardial infarction (MI), using serum cortisol as a surrogate marker for the severity of stress.

METHODS

Subjects with acute MI were prospectively recruited upon hospital admission. Serum glucose and cortisol were measured in addition to standard testing. Subjects were defined as having stress hyperglycemia (SH) if they had an admission glucose ≥7.8 mmol/L without a history of glucose intolerance. Subjects were followed up with glucose tolerance testing post-discharge.

RESULTS

Of the 200 subjects in the study, 58 had known diabetes/impaired glucose tolerance (IGT), and 45 had SH. There was a positive association between admission glucose and cortisol for the entire cohort (r_s = 0.26, p < 0.01). This relationship was present in the subgroup who had SH and then normal glucose post-discharge (r_s = 0.53, p = 0.03), but not in SH subjects who had diabetes/IGT on post-discharge testing. It was also evident amongst all subjects with normal glucose (r_s = 0.46, p < 0.01), but not those with diabetes/IGT in general. On multivariate analysis, admission glucose was a positive predictor and cortisol a negative predictor of abnormal glucose tolerance.

CONCLUSIONS

Our data suggests that SH with MI reflects either underlying glucose intolerance or more severe stress in people without glucose intolerance.

The Oxygen Paradox, the French Paradox, and age-related diseases

A paradox is a seemingly absurd or impossible concept, proposition, or theory that is often difficult to understand or explain, sometimes apparently self-contradictory, and yet ultimately correct or true. How is it possible, for example, that oxygen "a toxic environmental poison" could be also indispensable for life (Beckman and Ames Physiol Rev 78(2):547-81, 1998; Stadtman and Berlett Chem Res Toxicol 10(5):485-94, 1997)?: the so-called Oxygen Paradox (Davies and Ursini 1995; Davies Biochem Soc Symp 61:1-31, 1995). How can French people apparently disregard the rule that high dietary intakes of cholesterol and saturated fats (e.g., cheese and paté) will result in an early death from cardiovascular diseases (Renaud and de Lorgeril Lancet 339(8808):1523-6, 1992; Catalgol et al. Front Pharmacol 3:141, 2012; Eisenberg et al. Nat Med 22(12):1428-1438, 2016)?: the so-called, French Paradox. Doubtless, the truth is not a duality and epistemological bias probably generates apparently self-contradictory conclusions. Perhaps nowhere in biology are there so many apparently contradictory views, and even experimental results, affecting human physiology and pathology as in the fields of free radicals and oxidative stress, antioxidants, foods and drinks, and dietary recommendations; this is particularly true when issues such as disease-susceptibility or avoidance, "healthspan," "lifespan," and ageing are involved. Consider, for example, the apparently paradoxical observation that treatment with low doses of a substance that is toxic at high concentrations may actually induce transient adaptations that protect against a subsequent exposure to the same (or similar) toxin. This particular paradox is now mechanistically explained as "Adaptive Homeostasis" (Davies Mol Asp Med 49:1-7, 2016; Pomatto et al. 2017a; Lomeli et al. Clin Sci (Lond) 131(21):2573-2599, 2017; Pomatto and Davies 2017); the non-damaging process by which an apparent toxicant can activate biological signal transduction pathways to increase expression of protective genes, by mechanisms that are completely different from those by which the same agent induces toxicity at high concentrations. In this review, we explore the influences and effects of paradoxes such as the Oxygen Paradox and the French Paradox on the etiology, progression, and outcomes of many of the major human age-related diseases, as well as the basic biological phenomenon of ageing itself.

Cardioprotection: Where to from here?

The size of the myocardial infarction remains an important therapeutic target, because heart attack size correlates with mortality and heart failure. In this era, myocardial infarct size is reduced primarily by timely reperfusion of the infarct related coronary artery. Whereas numerous pre-clinical studies have shown that certain pharmacologic agents and therapeutic maneuvers reduce myocardial infarction size greater than reperfusion alone, very few of these therapies have translated to successful clinical trials or standard clinical use. In this review we discuss both the recent successes as well as recent disappointments, and describe some of the newer potential therapies from the preclinical literature that have not yet been tested in clinical trials.

Cardioprotective Effect of Anisodamine Against Myocardial Ischemia Injury and its Influence on Cardiomyocytes Apoptosis

Anisodamine is an ancient Chinese medicine derived from Tibet as a belladonna alkaloid, which is usually used for improvement of blood circulation in patients with organ phosphorus poisoning or shock. In this study, for the first time, we report its cardioprotective effects on preventing ischemia/reperfusion (I/R) injury of patients with acute myocardial infarction (AMI), and decreasing the myocardial infarction area and severity in heart of Sprague-Dawley (SD) rats. Our results suggest a potential molecular mechanism of anisodamine against the I/R injury in cardiomyocytes is associated with its anti-apoptotic effect. Anisodamine treatment decreases the expression of caspase-3 and caspase-8, and increases Bcl-2/Bax ratio in cardiomyocytes. Our data suggest that anisodamine can provide significant cardioprotection against I/R injury, potentially through the suppression of cardiomyocytes apoptosis.

Synergistic cardioprotective effects of Danshensu and hydroxysafflor yellow A against myocardial ischemia-reperfusion injury are mediated through the Akt/Nrf2/HO-1 pathway

In clinical practice, the traditional Chinese medicinal herbs, Radix Salvia Miltiorrhiza and Carthamus tinctorius L., are usually prescribed in combination due to their significant cardioprotective effects. However, the mechanisms responsible for these combined effects remain unknown. Thus, in this study, we investigated the mechanisms responsible for the combined effects of Danshensu (DSS) and hydroxysafflor yellow A (HSYA) by establishing a rat model of myocardial ischemia/reperfusion (MI/R), as well as a model of hypoxia/reoxygenation (H/R) using H9c2 cells. The combination index (CI) was calculated using the median-effect method. DSS and HSYA in combination led to a CI value of <1 as regards infarct size in vivo and cell viability in vitro. The rats with MI/R injury that were treated with DSS and/or HSYA were found to have significantly lower levels of creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI) and malondialdehyde (MDA), and a lower expressoin of 8-hydroxydeoxyguanosine (8-OHdG), and markedly enhanced superoxide dismutase (SOD) activity. Our in vitro experiments revealed that the cells treated with DSS and/or HSYA had a reduced lactate dehydrogenase (LDH) activity and a decreased percentage of cell apoptosis (increased Bcl-2/Bax ratio, decreased expression of cleaved caspase-3). DSS and HSYA increased the expression of heme oxygenase-1 (HO-1), the phosphorylation of Akt and the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). Furthermore, the Akt inhibitor, LY294002, partially hampered the expression of Nrf2 and HO-1. The HO-1 inhibitor, zinc protoporphyrin IX (ZnPP‑IX), did not decrease the expression of p-Akt and Nrf2, although it abolished the anti-apoptotic and antioxidant effects of DSS and HSYA. The findings of our study thus demonstrate that DSS and HSYA confer synergistic cardioprotective effects through the Akt/Nrf2/HO-1 signaling pathway, to certain extent, by enhancing the antioxidant defense system and exerting anti-apoptotic effects.

N-Acetylcysteine Restores Sevoflurane Postconditioning Cardioprotection against Myocardial Ischemia-Reperfusion Injury in Diabetic Rats

The effect of sevoflurane postconditioning (sevo-postC) cardioprotection is compromised in diabetes which is associated with increased oxidative stress. We hypothesized that antioxidant N-Acetylcysteine may enhance or restore sevo-postC cardioprotection in diabetes. Control or streptozotocin-induced Type 1 diabetic rats were either untreated or treated with N-Acetylcysteine for four weeks starting at five weeks after streptozotocin injection and were subjected to myocardial ischemia-reperfusion injury (IRI), in the absence or presence of sevo-postC. Diabetes showed reduction of cardiac STAT3 activation (p-STAT3) and adiponectin with concomitantly increase of FoxO1 and CD36, which associated with reduced sevo-postC cardioprotection. N-Acetylcysteine and sevo-postC synergistically reduced the infarct size in diabetic groups. N-Acetylcysteine remarkably increased cardiac p-STAT3 which was further enhanced by sevo-postC. N-Acetylcysteine but not sevo-postC decreased myocardial FoxO1 while sevo-postC but not N-Acetylcysteine significantly increased myocardiac adiponectin in diabetic rats. It is concluded that late stage diabetic rats displayed reduction of cardiac p-STAT3, adiponectin deficiency, and increase of FoxO1 and CD36 expression, which may be responsible for the loss of myocardial responsiveness to sevo-postC cardioprotection. N-Acetylcysteine restored Sevo-postC cardioprotection in diabetes possibly through enhancing cardiac p-STAT3 and adiponectin and reducing Fox1 and CD36.

Metabolic Syndrome is Associated With Higher Wall Motion Score and Larger Infarct Size After Acute Myocardial Infarction

Background:

Infarct size is an important surrogate end point for early and late mortality after acute myocardial infarction. Despite the high prevalence of metabolic syndrome in patients with atherosclerotic diseases, adequate data are still lacking regarding the extent of myocardial necrosis after acute myocardial infarction in these patients.

Objectives:

In the present study we aimed to compare myocardial infarction size in patients with metabolic syndrome to those without metabolic syndrome using peak CK-MB and cardiac troponin I (cTnI) at 72 hours after the onset of symptoms.

Patients and Methods:

One-hundred patients with metabolic syndrome (group I) and 100 control subjects without metabolic syndrome (group II) who experienced acute myocardial infarction were included in the study. Diagnosis of metabolic syndrome was based on the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) guidelines published in 2001. Myocardial infarction size was compared between the two groups of patients using peak CK-MB and cTnI level in 72 hours after the onset of symptoms.

Results:

Peak CK-MB and cTnI in 72 hours were found to be significantly higher in patients with metabolic syndrome compared with control subjects (both P < 0.001). Patients with metabolic syndrome also had markedly higher wall motion abnormality at 72 hours after the onset of symptoms as assessed by echocardiographically-derived Wall Motion Score Index (WMSI) (P < 0.001). Moreover, statistically significant relationships were found between WMSI and peak CK-MB and also cTnI at 72 hours (Spearman's rho = 0.56, P < 0.001 and Spearman's rho = 0.5, P < 0.001; respectively). However, association between WMSI and left ventricular ejection fraction was insignificant (Spearman's rho = -0.05, P = 0.46).

Conclusions:

We showed that patients with metabolic syndrome have larger infarct size compared to control subjects.

Cardiac troponin I for prediction of clinical outcomes and cardiac function through 3-month follow-up after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction

BACKGROUND

Circulating levels of cardiac troponin I (cTnI) after ST-segment elevation myocardial infarction (STEMI) are associated with infarct size and chronic left ventricular dysfunction, but the relation to clinical end points and biochemical measures of global cardiac function remains less well defined.

METHODS

One thousand sixty-six patients receiving primary percutaneous coronary intervention (PCI) in the PROTECTION AMI trial were studied in a post hoc analysis. Cardiac troponin I was measured at several time points during the index hospitalization, and patients were followed up for 3 months before reassessment including N-terminal pro-B-type natriuretic peptide (NT-proBNP) and left ventricular ejection fraction (LVEF) measurements.

RESULTS

The median (quartile 1-3) cTnI levels were 0.4 (0.1-0.4) μg/L at admission, 33.1 (12.8-72.1) μg/L after 16 to 24 hours, and 9.1 (3.9-17.5) μg/L after 70 to 80 hours. In adjusted models, all post-PCI single points, peak, and area under curve were found to be independently associated with clinical events, NT-proBNP >118 pmol/L, or LVEF <40% (P for all <.001). When cTnI was added to a baseline risk model for prediction of clinical events, the C statistic improved from 0.779 to 0.846 (16-24 hours) and 0.859 (70-80 hours). Quantified by integrated discrimination improvement, the addition of cTnI significantly augmented prediction ability (relative integrated discrimination improvement 44%-154%; P for all ≤.001). Consistent improvements in discrimination of NT-proBNP >118 pmol/L and LVEF <40% were observed.

CONCLUSIONS

Cardiac troponin I measured after primary PCI for STEMI is independently associated with clinical outcomes and cardiac function through 3-month follow-up. These results suggest that cTnI levels are a useful risk stratification tool in STEMI patients.

Ischaemic postconditioning reduces infarct size: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Infarct size (IS) is a major determinant of patient outcome after acute ST-segment elevation myocardial infarction (STEMI). Interventions aimed at reducing reperfusion injury, such as cardiac ischaemic postconditioning (IPost), may reduce IS and improve clinical outcomes. IPost has been shown to be feasible in patients with STEMI treated by primary percutaneous coronary intervention (PPCI).

AIMS

To provide an updated summary of the efficacy of IPost, assessed by analysing accurate surrogate markers of IS.

METHODS

We performed a meta-analysis of randomized controlled trials that evaluated the efficacy of IPost in STEMI patients undergoing PPCI. The main outcome was area under the curve of serum creatine kinase release (CK-AUC). Secondary outcomes were other surrogate biomarkers of IS, complete ST-segment resolution, direct measurement of IS by single-photon emission computed tomography and estimation of IS by cardiac magnetic resonance (CMR-IS).

RESULTS

Eleven studies were retrieved, including 1313 STEMI patients undergoing PPCI with or without IPost. Compared with controls, we observed a significant reduction in CK-AUC (standard mean difference [SMD] -2.84 IU/L, 95% CI -5.43 to -0.25 IU/L; P=0.03). Other surrogate markers, such as CMR-IS (SMD -0.36, 95% CI -0.88 to 0.15; P=0.16), showed a non-significant IS reduction in the IPost group.

CONCLUSIONS

This meta-analysis, dealing with accurate surrogate markers of IS, suggests that IPost reduces IS. However, results should be interpreted cautiously because of limited sample sizes and significant heterogeneity. Whether this translates into improvements in cardiac function and patient prognosis still needs to be demonstrated in larger prospective randomized controlled studies that are powered sufficiently.

Prognostic implications of creatine kinase-MB measurements in ST-segment elevation myocardial infarction patients treated with primary percutaneous coronary intervention

BACKGROUND

Peak creatine kinase (CK)-MB concentration is related to reperfusion success and clinical outcomes after fibrinolytic therapy for acute myocardial infarction. However, prognostic implications of CK-MB measurements after primary percutaneous coronary intervention (PCI), which provides more predictable and consistent reperfusion, are unknown.

METHODS

We pooled 2,042 primary PCI-treated ST-segment elevation myocardial infarction (STEMI) patients from 3 trials with serial core laboratory-determined CK-MB measurements; 1,799 patients (88.1%) who survived to 36 hours and had ≥4 CK-MB measurements were studied. Cox regression modeling was performed to quantify the association between peak CK-MB concentration (and area under the time-concentration curve [AUC]) and mortality at 6 months, and death or congestive heart failure at 90 days.

RESULTS

The median (25th-75th percentiles) peak CK-MB concentration and AUC measurement through 36 hours were 239 (109-429) ng/mL and 4,263 (2,081-7,124) ng/(mL h), respectively. By multivariable analysis, peak CK-MB concentration and AUC measurement were independently associated with 6-month mortality (adjusted hazard ratio [HR] 1.15, 95% CI 1.05-1.25, per 100-ng/mL increase, P = .002; and adjusted HR 1.09, 95% CI 1.03-1.14, per 1,000-ng/[mL h] increase, P < .001, respectively) and 90-day death or congestive heart failure (adjusted HR 1.26, 95% CI 1.18-1.34, P < .001; and adjusted HR 1.15, 95% CI 1.11-1.19, P < .001, respectively).

CONCLUSIONS

Peak CK-MB concentration and AUC measurement are independent predictors of 3- to 6-month cardiovascular outcomes in primary PCI-treated STEMI patients. Our findings guide application of these measurements as efficacy end points in early-phase studies evaluating new therapies for STEMI.

Role of MIF in myocardial ischaemia and infarction: insight from recent clinical and experimental findings

First discovered in 1966 as an inflammatory cytokine, MIF (macrophage migration inhibitory factor) has been extensively studied for its pivotal role in a variety of inflammatory diseases, including rheumatoid arthritis and atherosclerosis. Although initial studies over a decade ago reported increases in circulating MIF levels following acute MI (myocardial infarction), the dynamic changes in MIF and its pathophysiological significance following MI have been unknown until recently. In the present review, we summarize recent experimental and clinical studies examining the diverse functions of MIF across the spectrum of acute MI from brief ischaemia to post-infarct healing. Following an acute ischaemic insult, MIF is rapidly released from jeopardized cardiomyocytes, followed by a persistent MIF production and release from activated immune cells, resulting in a sustained increase in circulating levels of MIF. Recent studies have documented two distinct actions of MIF following acute MI. In the supra-acute phase of ischaemia, MIF mediates cardioprotection via several distinct mechanisms, including metabolic activation, apoptosis suppression and antioxidative stress. In prolonged myocardial ischaemia, however, MIF promotes inflammatory responses with largely detrimental effects on cardiac function and remodelling. The pro-inflammatory properties of MIF are complex and involve MIF derived from cardiac and immune cells contributing sequentially to the innate immune response evoked by MI. Emerging evidence on the role of MIF in myocardial ischaemia and infarction highlights a significant potential for the clinical use of MIF agonists or antagonists and as a unique cardiac biomarker.

Rapid Induction of Hypothermia by the ThermoSuit System Profoundly Reduces Infarct Size and Anatomic Zone of No Reflow Following Ischemia-Reperfusion in Rabbit and Rat Hearts

INTRODUCTION

Although hypothermia reduces myocardial infarct size, noninvasive and rapid cooling methods are lacking. This study tests the effectiveness of a novel cooling apparatus on myocardial infarct size and no-reflow area in 2 models of coronary artery occlusion (CAO).

METHODS AND RESULTS

Animals were randomized to normothermic (N) or hypothermic (H) groups after isolation of a proximal coronary artery. Animals were subjected to 30 minutes CAO and 3 hours reperfusion. In protocol 1 (rabbit, n = 8 per group), hypothermia was initiated, using the ThermoSuit apparatus (convective-immersion cooling), 5 minutes after the onset of CAO to a goal temperature of ∼32°C. In protocol 2 (rat, n = 5 per group), hypothermia was initiated 2 minutes after the onset of CAO to a goal temperature of ∼30°C. Goal temperature was reached in ∼20 minutes. In protocol 1, hypothermia caused an 82% reduction in infarct size as a percentage of the ischemic risk zone (N, 44% ± 5%; H; 8% ± 2%, P < 0.001) and an 89% reduction in the no-reflow area (N, 44% ± 4%; H, 5% ± 1%, P < 0.001). In protocol 2, hypothermia caused a 73% infarct size reduction (N, 51% ± 5%; H, 14% ± 6%, P < 0.01) and a 99% reduction in the no-reflow area (N, 33% ± 5%; H, 0.4% ± 0.3%, P < 0.01).

CONCLUSION

The ThermoSuit device induced rapid hypothermia and limited infarct size and no reflow to the greatest extent ever observed in this laboratory with a single intervention.

Relationship between ST-segment resolution and anterior infarct size after primary percutaneous coronary intervention: analysis from the INFUSE-AMI trial

AIMS

ST-segment resolution (STR) after reperfusion therapy has been shown to correlate with prognosis in patients with ST-segment elevation myocardial infarction (STEMI). We investigated whether acute ECG measurements also correlate with ultimate infarct size.

METHODS AND RESULTS

The INFUSE-AMI trial randomized 452 patients with anterior STEMI to intracoronary bolus abciximab vs. no abciximab, and to thrombus aspiration vs. no aspiration. Infarct size as percentage of total LV mass was calculated by cardiac magnetic resonance imaging (MRI) 30 days post intervention. Five ECG methods were analysed for their ability to predict MRI infarct mass: (1) summed STR across all infarct-related ECG leads (ΣSTR); (2) STR in the single lead with maximum baseline ST-segment elevation (maxSTR); (3) summed residual ST-segment elevation across all infarct-related leads at 60 min post intervention (ΣST residual); (4) maximum residual ST-segment elevation in the worst single lead at 60 min post intervention (maxST residual); (5) number of new significant Q-waves (Qwave) at 60 min. All ECG methods strongly correlated with 30-day MRI infarct mass (all p<0.003). Simpler ECG measurements such as maxSTresidual and Qwave were as predictive as more complex measurements. A subset analysis of 158 patients who had microvascular obstruction (MVO) determined by MRI 5 days post intervention also showed strong correlations of MVO with the ECG measures.

CONCLUSIONS

ST-segment and Q-wave changes after primary PCI in anterior STEMI strongly correlated with 30-day infarct size by MRI. In particular, maxST residual and Qwave at 60 min are simple ECG parameters that offer rapid analysis for prognostication.

N-Acetylcysteine and allopurinol up-regulated the Jak/STAT3 and PI3K/Akt pathways via adiponectin and attenuated myocardial postischemic injury in diabetes

N-Acetylcysteine (NAC) and allopurinol (ALP) synergistically reduce myocardial ischemia reperfusion (MI/R) injury in diabetes. However, the mechanism is unclear. We postulated that NAC and ALP attenuated diabetic MI/R injury by up-regulating phosphatidylinositol 3-kinase/Akt (PI3K/Akt) and Janus kinase 2/signal transducer and activator of transcription-3 (JAK2/STAT3) pathways subsequent to adiponectin (APN) activation. Control (C) or streptozotocin-induced diabetic rats (D) were untreated or treated with NAC and ALP followed by MI/R. D rats displayed larger infarct size accompanied by decreased phosphorylation of Akt, STAT3 and decreased cardiac nitric oxide (NO) and APN levels. NAC and ALP decreased MI/R injury in D rats, enhanced phosphorylation of Akt and STAT3, and increased NO and APN. High glucose and hypoxia/reoxygenation exposure induced cell death and Akt and STAT3 inactivation in cultured cardiomyocytes, which were prevented by NAC and ALP. The PI3K inhibitor wortmannin and Jak2 inhibitor AG490 abolished the protection of NAC and ALP. Similarly, APN restored posthypoxic Akt and STAT3 activation and decreased cell death in cardiomyocytes. Gene silencing with AdipoR2 siRNA or STAT3 siRNA but not AdipoR1 siRNA abolished the protection of NAC and ALP. In conclusion, NAC and ALP prevented diabetic MI/R injury through PI3K/Akt and Jak2/STAT3 and cardiac APN may serve as a mediator via AdipoR2 in this process.

Susceptibility to myocardial ischemia reperfusion injury at early stage of type 1 diabetes in rats

Background

Large body of evidences accumulated in clinical and epidemiological studies indicate that hearts of diabetic subjects are more sensitive to ischemia reperfusion injury (IRI), which results in a higher rate of mortality at post-operation than that of non-diabetes. However, experimental results are equivocal and point to either increased or decreased susceptibility of the diabetic hearts to IRI, especially at the early stage of the disease. The present study was designed to test the hypothesis that the duration/severity of the indexed ischemia is a major determinant of the vulnerability to myocardial IRI at early stage of diabetes.

Methods

Four weeks streptozotocin (STZ)-induced diabetic (D) and non-diabetic (C) Sprague–Dawley rats were randomly assigned to receive 30 or 45 min of left anterior descending artery ligation followed by 2 or 3 hours of reperfusion, respectively. Cardiac function was recorded by using Pressure-Volume (PV) conduction system. Myocardial infarct size was determined with triphenyltetrazolium chloride staining. Plasma Creatine kinase-MB (CK-MB), Lactate dehydrogenase (LDH) release, myocardial nitric oxide(NO) content and nitrotyrosine formation, 15-F_2t-Isoprostane and plasma superoxide dismutase (SOD) were measured with colorimetric assays. Cardiomyocyte apoptosis was assessed by TUNEL staining. Myocardial TNFα, Caspase-3, STAT3, Akt, and GSK-3β were determined by Western blotting.

Results

Prolongation of ischemia but not reperfusion from 30 min to 45 min significantly increased infarct size in D compared to C rats (P < 0.05), accompanied with significantly increased plasma CK-MB (P < 0.05). Prolongation of the duration of either ischemia or reperfusion significantly increased plasma LDH release and myocardial 15-F_2t-Isoprostane and reduced plasma SOD activity, with concomitant reduction of myocardial NO and increase of nitrotyrosine formation in D relative to C (P < 0.05). Prolongation of ischemia and reperfusion significantly reduced left ventricular ejection fraction and increased the peak rate of pressure, accompanied with increased end systolic pressure in D relative to C rats (P < 0.05) but reduced phosphorylations of myocardial STAT3 at site Ser727 and Akt at site Ser473 as well as GSK-3β at Ser 9 (P < 0.05).

Conclusions

Diabetic hearts, even at early stage of the disease are more sensitive to IRI, and this increased severity of post-ischemic myocardial injury depends more on the duration of ischemia than that of reperfusion.

N-acetylcysteine and allopurinol confer synergy in attenuating myocardial ischemia injury via restoring HIF-1α/HO-1 signaling in diabetic rats

OBJECTIVES

To determine whether or not the antioxidants N-acetylcysteine (NAC) and allopurinol (ALP) confer synergistic cardioprotection against myocardial ischemia/reperfusion (MI/R) injury by stabilizing hypoxia inducible factor 1α (HIF-1α)/heme oxygenase 1 (HO-1) signaling in diabetic myocardium.

METHODS

Control or diabetic [streptozotocin (STZ)-induced] Sprague Dawley rats received vehicle or NAC, ALP or their combination for four weeks starting one week after STZ injection. The animals were then subjected to thirty minutes of coronary artery occlusion followed by two hours reperfusion in the absence or presence of the selective HO-1 inhibitor, tin protoporphyrin-IX (SnPP-IX) or the HIF-1α inhibitor 2-Methoxyestradiol (2ME2). Cardiomyocytes exposed to high glucose were subjected to hypoxia/re-oxygenation in the presence or absence of HIF-1α and HO-1 achieved by gene knock-down with related siRNAs.

RESULTS

Myocardial and plasma levels of 15-F2t-isoprostane, an index of oxidative stress, were significantly increased in diabetic rats while cardiac HO-1 protein and activity were reduced; this was accompanied with reduced cardiac protein levels of HIF-1α, and increased post-ischemic myocardial infarct size and cellular injury. NAC and ALP given alone and in particular their combination normalized cardiac levels of HO-1 and HIF-1α protein expression and prevented the increase in 15-F2t-isoprostane, resulting in significantly attenuated post-ischemic myocardial infarction. NAC and ALP also attenuated high glucose-induced post-hypoxic cardiomyocyte death in vitro. However, all the above protective effects of NAC and ALP were cancelled either by inhibition of HO-1 or HIF-1α with SnPP-IX and 2ME2 in vivo or by HO-1 or HIF-1α gene knock-down in vitro.

CONCLUSION

NAC and ALP confer synergistic cardioprotection in diabetes via restoration of cardiac HIF-1α and HO-1 signaling.

The safety and efficacy of intracoronary nitrite infusion during acute myocardial infarction (NITRITE-AMI): study protocol of a randomised controlled trial

INTRODUCTION

Acute myocardial infarction (AMI) is a major cause of death and disability in the UK and worldwide. Presently, timely and effective reperfusion with primary percutaneous coronary intervention (PPCI) remains the most effective treatment strategy for limiting infarct size, preserving left ventricular ejection fraction (LVEF) and improving clinical outcomes. However, the process of reperfusion can itself induce cardiomyocyte death, known as myocardial reperfusion injury, for which there is currently no effective therapy. Extensive preclinical evidence exists to suggest that sodium nitrite (as a source of endogenous nitric oxide) is an effective therapeutic strategy for preventing myocardial reperfusion injury. The purpose of NITRITE-AMI is to test whether sodium nitrite reduces reperfusion injury and subsequent infarct size in patients undergoing PPCI for MI.

METHODS AND DESIGN

NITRITE-AMI is a double-blind, randomised, single-centre, placebo-controlled trial to determine whether intracoronary nitrite injection reduces infarct size in patients with myocardial infarction undergoing primary angioplasty. The study will enrol 80 patients presenting with ST-elevation myocardial infarction. Patients will be randomised to receive either a bolus of intracoronary sodium nitrite or placebo (sodium chloride) at the time of PPCI. The primary outcome is infarct size assessed by creatine kinase area under the curve (AUC) over 48 h. Secondary endpoints include troponin T AUC and infarct size, LV dimensions and myocardial salvage index assessed by cardiac MR (CMR), markers of platelet reactivity and inflammation, the safety and tolerability of intracoronary nitrite, and 1 year major adverse cardiac events.

ETHICS AND DISSEMINATION

The study is approved by the local ethics committee (NRES Committee London West London: 11/LO/1500) and by the Medicines and Healthcare Products Regulatory Agency (MHRA) (EudraCT nr. 2010-022460-12). The results of the trial will be published according to the CONSORT statement and will be presented at conferences and reported in peer-reviewed journals.

TRIAL REGISTRATION

United Kingdom Clinical Research Network (Study ID 12117), http://clinicaltrials.gov (NCT01584453) and Current Controlled Trials (ISRCTN:38736987).

Circadian dependence of infarct size and left ventricular function after ST elevation myocardial infarction

RATIONALE

In rodents, infarct size after ischemia/reperfusion exhibits a circadian dependence on the time of coronary occlusion. It is not known if a similar circadian dependence of infarct size occurs in humans.

OBJECTIVE

To determine if humans exhibit a circadian dependence of infarct size in the setting of ST elevation myocardial infarction (STEMI).

METHODS AND RESULTS

A retrospective analysis of 1031 patients with STEMI referred for primary percutaneous coronary intervention with known ischemic times between 1 and 6 hours identified 165 patients with occluded arteries on presentation without evidence of preinfarction angina or collateral blood flow. Both ischemic duration and angiographic area at risk were not dependent on time of infarct onset. We observed that the extent of infarct size measured by creatine kinase release was significantly associated with time of day onset of infarction (P<0.0001). The greatest myocardial injury occurred at 1:00 am onset of ischemia and 5:00 am onset of reperfusion, with the peak creatine kinase measured at the peak of the curve being 82% higher than that recorded at the trough. Similarly, left ventricular ejection fraction measured within 2 days of infarction was also dependent on time of onset of STEMI with the absolute left ventricular ejection fraction at peak >7% higher than at trough (43% vs 51%; P<0.03). These findings were supported by a subgroup of patients (n = 45) who underwent cardiac MRI measurements of infarct size and area-at-risk measurements.

CONCLUSIONS

The results of this study demonstrate for the first time in humans that myocardial infarct size and left ventricular function after STEMI have a circadian dependence on the time of day onset of ischemia.

Stents and statins: history, clinical outcomes and mechanisms

The 1980s witnessed the inception of both stents and 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors (statins). While they evolved separately, it was soon realized that they each offered a unique and powerful mechanism for targeting the major offender in cardiovascular disease, namely atherosclerosis. Coincidentally, the first statin was approved by the US FDA in 1987, the same year that the coronary stent was conceived. Since that time, stents and statins have revolutionized the field of cardiovascular medicine and their paths have been intertwined. Several pivotal randomized clinical trials have established statins as an effective therapy for improving clinical outcomes after percutaneous coronary intervention (PCI) among patients presenting with stable coronary artery disease and acute coronary syndromes. In addition, chronic statin therapy and acute loading of statins prior to PCI has consistently been shown to limit periprocedural myocardial necrosis. The mechanism for improved clinical outcomes with statins has clearly been associated with statin-induced reductions in LDL. In addition, statins may also exert 'pleiotropic' effects, independent of LDL lowering, that might counteract the inflammatory and prothrombotic mileu created with PCI. This article provides a brief historical perspective of the evolution of the use of statins and stents in patients with coronary artery disease, an evaluation of the available clinical data supporting the use of statins in patients undergoing PCI across a wide spectrum of clinical scenarios, and a discussion of the potential mechanisms of the benefit of statins in these patients.

Relation between infarct size in ST-segment elevation myocardial infarction treated successfully by percutaneous coronary intervention and left ventricular ejection fraction three months after the infarct

The goal of this analysis was to determine the relation between myocardial infarct size and left ventricular (LV) ejection fraction (EF) in patients with ST-segment elevation myocardial infarction (STEMI) after primary percutaneous coronary intervention (pPCI) using cardiovascular magnetic resonance imaging (CMR). After STEMI, LVEF and infarct size correlate with prognosis, but the relation between infarct size and LVEF is incompletely known. Consecutive subjects presenting to a single center with STEMI treated with pPCI were enrolled, and cine functional and late gadolinium enhancement CMR was performed 3 months after presentation. From cine images, LVEF was calculated using volumetric summation of disks method. Infarct size was measured as percent LV myocardial volume with late gadolinium enhancement. In the 78 patients enrolled (mean age 54.5 years, range 42 to 82), median LVEF was 56% (interquartile range 49 to 62) and median infarct size was 11% (interquartile range 5 to 18). Of the 53 patients with infarct size <15%, all had LVEF >40%, and there was no significant relation between infarct size and LVEF (slope -0.43, R(2) = 0.045, p = 0.13). In patients with infarct size > or =15%, there was a significant negative linear association between infarct size and LVEF (slope -1.21, R(2) = 0.66, p <0.001), such that for every 5% increase in infarct size, there was a 6.1% decrease in LVEF. In conclusion, there is a negative linear relation between infarct size and LVEF for moderate to large infarcts. For small infarcts there is no significant relation between infarct size and LVEF. Up to 15% of LV myocardial volume may be infarcted before there is any appreciable decrease in LVEF.

Door-to-balloon time in primary percutaneous coronary intervention predicts degree of myocardial necrosis as measured using cardiac biomarkers

Reduced door-to-balloon time in primary percutaneous coronary intervention for the treatment of ST-elevation myocardial infarction has been associated with lower cardiac mortality rates. However, it remains unclear whether door-to-balloon time is predominantly a surrogate for overall peri-myocardial infarction care and is not independently predictive of outcomes, particularly when differences in door-to-balloon time have narrowed and previous studies have contained myocardial infarction-selection bias.We analyzed 179 consecutive patients who presented emergently at our cardiac catheterization laboratory with ST-elevation myocardial infarction within 12 hours of symptom onset and who underwent primary percutaneous coronary intervention within 3 hours of presentation. Our curve estimation regression model used the natural logarithm (ln) of area under the curve (AUC) of creatine kinase to evaluate the effect of door-to-balloon time on cardiac biomarker levels. We correlated ln (AUC-creatine kinase) with improvement of left ventricular ejection fraction at follow-up and with the intermediate-term mortality rate.Median door-to-balloon time was 87 minutes (interquartile range, 65-113 min). The ln (AUC-creatine kinase) correlated significantly with door-to-balloon time (r=0.2, P=0.02). Upon propensity-score analysis, door-to-balloon time remained a significant independent predictor of ln (AUC-creatine kinase) (beta=0.15, P=0.03). Upon use of a Cox regression model, ln (AUC-creatine kinase) independently predicted death (P=0.04) and recovery of left ventricular function (P=0.001) at follow-up (mean, 14 mo).Longer door-to-balloon time independently predicts increased myocardial cell damage, and ln (AUC-creatine kinase) predicts improvement in left ventricular systolic function and intermediate-term death after ST-elevation myocardial infarction.

Relation between myocardial infarct size and ventricular tachyarrhythmia among patients with preserved left ventricular ejection fraction following fibrinolytic therapy for ST-segment elevation myocardial infarction

In the era of early reperfusion therapy for ST-segment elevation myocardial infarction, preserved left ventricular (LV) function is common. Despite preservation of LV ejection fraction (LVEF), there remains a spectrum of risk for adverse cardiovascular events, including ventricular tachycardia (VT) and ventricular fibrillation (VF). Larger infarct size has been independently associated with death, VT/VF, and heart failure in the post-myocardial infarction population. It was hypothesized that infarct size, as estimated by peak serum creatine kinase (CK)-MB concentration, would be associated with the incidence of VT/VF in patients with preserved LV function after ST-segment elevation myocardial infarctions. The Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis In Myocardial Infarction 28 (CLARITY-TIMI 28) study enrolled 3,491 patients with ST-segment elevation myocardial infarctions who underwent fibrinolytic therapy. The association between estimated infarct size (ratio of peak CK-MB to the upper limit of normal), the LVEF (measured using left ventriculography or echocardiography), and the incidence of VT/VF through 30 days was assessed. A total of 1,436 patients underwent assessments of LV function, of whom 1,133 had adequate CK-MB for analysis. The median LVEF in this group was 55% (interquartile range 45% to 65%), and most patients (n = 814 [87.1%]) had LVEF > or =40%. Among patients with LVEF > or =40%, the ratio of peak CK-MB to the upper limit of normal was significantly associated with the incidence of VT/VF through 30 days (2.2%, 3.7%, and 5.5% across tertiles, respectively, p = 0.041 for trend) and the incidence of the composite of cardiovascular death, heart failure, shock, and VT/VF through 30 days (3.7%, 6.0%, 8.5%, respectively, p = 0.018 for trend). In conclusion, in patients with ST-segment elevation myocardial infarction with preserved LV function after reperfusion therapy, larger infarct size, as estimated by peak serum CK-MB concentration, is significantly associated with VT/VF as well as other adverse clinical outcomes.

Pretreatment with statins may reduce cardiovascular morbidity and mortality after elective surgery and percutaneous coronary intervention: clinical evidence and possible underlying mechanisms

After Murry et al (Circulation 1986;74:1124) described ischemic preconditioning in 1986, numerous pharmacologic agents with effects simulating ischemic preconditioning have been identified. With the exception of beta-blockers, most such agents have no proven clinical benefit in the setting of myocardial ischemia. The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been consistently demonstrated to reduce myocardial injury, morbidity, and mortality in the clinical setting, both perioperatively and after percutaneous coronary intervention. Although the precise mechanism underlying their additional protective effect is not yet fully understood, it appears to be immediate in action and independent of cholesterol lowering. Experimental data from several animal models of ischemia and reperfusion have demonstrated an infarct size reduction with prior statin administration. At the cellular level, statins activate the phosphoinositol-3 kinase and Akt signaling cascade. Statins also increase expression and activity of endothelial nitric oxide synthase, inducible nitric oxide synthase, ecto-5'-nucleotidase, cyclooxygenase-2, and other prostaglandin synthesis pathway enzymes. However, when given by oral route to animals, relatively high dose of statins is needed to exert maximal protective effect. Understanding the underlying mechanism may enable to maximize the protective effect by using drug combination with synergistic activity and to avoid medications that may interfere with the protective effect of statins (ie, selective and nonselective cyclooxygenase-2 inhibition). Future clinical applications include preoperative and periprocedural risk reduction.