Interleukin-33, matrix metalloproteinase-9, and tissue inhibitor [corrected] of matrix metalloproteinase-1 in myocardial infarction

BACKGROUND/AIMS

Acute coronary syndrome (ACS) is characterized by increased inflammatory processes and endothelial activation. We investigated the association between ACS and inflammatory mediators and matrix-degrading enzymes.

METHODS

We prospectively enrolled 55 consecutive patients with ACS: 25 with unstable angina (UA) and 30 with non-ST elevated myocardial infarction (NSTEMI). For comparison, 25 age- and sex-matched subjects with no significant coronary artery stenosis were included as the control group. Peripheral serum levels of interleukin (IL)-33, matrix metalloproteinase (MMP)-9, tissue inhibitor of MMP-1, and C-reactive protein (CRP) were measured on admission, and at 12, 24, 48, and 72 hours after the initial evaluation.

RESULTS

Compared to serum levels in the control group, serum levels of IL-33 decreased in the NSTEMI group (p < 0.05), and levels of MMP-9 and tissue inhibitor of matrix metalloproteinase (TIMP)-1 increased in the UA group (p < 0.01, p < 0.05, respectively) and NSTEMI group (p < 0.05, p < 0.05, respectively). IL-33 levels were significantly lower on admission than at 12 hours after the initial evaluation (p < 0.05). IL-33 levels were negatively correlated with MMP-9 levels (r = -0.461, p < 0.05) and CRP levels (r = -0.441, p < 0.05).

CONCLUSIONS

Elevated levels of MMP-9, TIMP-1, and decreased levels of IL-33 play a role in the development and progression of ACS.

Association of lipoprotein-associated phospholipase A₂ with characteristics of vulnerable coronary atherosclerotic plaques

PURPOSE

Lipoprotein-associated phospholipase A₂ (Lp-PLA₂) is an inflammatory enzyme expressed in atherosclerotic plaques. We investigated the association of circulating Lp-PLA₂ with characteristics of vulnerable coronary atherosclerotic plaques.

MATERIALS AND METHODS

We recruited 113 patients with either unstable angina (UA, n=59) and stable angina (SA, n=54) by coronary angiography. Thirty-six healthy subjects served as controls. Intravascular ultrasound (IVUS) was used to evaluate the characteristics of coronary atherosclerotic plaque, and serum Lp-PLA₂ concentration was measured as well.

RESULTS

Lp-PLA₂ concentration was significantly higher in both UA and SA patients [(396±36) μg/L and (321±39) μg/L, respectively] compared with the controls [(127 ± 49) μg/L, p<0.01], and higher in UA than SA group. IVUS findings showed that remodeling index (RI) (0.91 ± 0.15 vs. 0.85 ± 0.11, p=0.005) and eccentricity index (EI) (0.73 ± 0.16 vs. 0.65 ± 0.22, p=0.039) were larger in UA than in SA group, and fibrous caps were thicker in SA than UA group [(0.91 ± 0.23) mm vs. (0.63 ± 0.21) mm, p=0.032]. Moreover, Lp-PLA₂ correlated positively with EI (r=0.439, p<0.01) and RI (r=0.592, p<0.05) in UA group. There was an inverse relationship between Lp-PLA₂ and fibrous cap thickness in both UA (r=-0.587, p<0.001) and SA (r=-0.318, p<0.05) groups. The independent risk factors in UA group were Lp-PLA₂ (OR=1.055, 95% CI: 1.03-1.08, p=0.013), LDL-cholesterol (OR=0.032, 95% CI: 0.00-0.05, p=0.041) and fibrous cap thickness (OR=0.008, 95% CI: 0.00-0.45, p=0.019). Lp-PLA₂ was strongly associated with both EI and fibrous cap thickness in both groups.

CONCLUSION

Serum level of Lp-PLA₂ is associated with both eccentricity index and fibrous cap thickness in both UA and SA groups. Elevated levels of circulating Lp-PLA₂ might to be a strong risk factor and more serious for unstable angina than stable angina.

Pharmacological inhibition of leukotriene biosynthesis: effects on the heart conductance

Leukotrienes are lipid mediators produced via 5-lipooxygenase pathway of arachidonic acid. At least two cysteinyl-leukotrienes receptors are highly expressed in the heart, including the conduction system. Coronary angiography or angioplasty is accompanied by release of cysteinyl leukotrienes into coronary circulation and into urine. We tested the hypothesis that inhibition of leukotrienes biosynthesis would affect the conductance system function. In a double-blind placebo controlled study, patients with stable angina undergoing elective coronary catheterization or angioplasty were randomly assigned to 48 hrs treatment with a 5-lipoxgenase inhibitor (n=54) or placebo (n=49). ECG Holter recording was carried out for 24 hrs before and after the procedure and urinary leukotriene E(4) measurements were done. Inhibition of 5-lipoxygenase caused 26% reduction of urinary leukotriene E(4), associated with: 1) decrease in heart rate by about 7%, 2) enhanced heart rate variability; 3) protection against depressions in atrioventricular conductance and ventricular repolarization induced by the procedure. No effects on either arrhythmias, or ECG patterns of ischemia were noted. We conclude that pharmacological inhibition of 5-lipoxygenase, shortly before percutaneous coronary intervention, reveals specific actions of leukotrienes on the heart rhythm. Inhibitors of 5-lipoxygenase might be of interest as a novel class of cardiac drugs affecting the conductive system.

Increased granzyme B production from peripheral blood mononuclear cells in patients with acute coronary syndrome

OBJECTIVES

To clarify the role of granzyme B in acute coronary syndrome.

DESIGN AND SETTING

Granzyme B is a member of the serine esterase family released from cytotoxic lymphocytes and plays an important role in cellular apoptosis by activating intracellular caspases. Granzyme B expression was compared between patients with stable and unstable angina pectoris (UAP).

PATIENTS

173 patients with coronary artery disease (CAD) were enrolled. 84 patients were found to have stable angina pectoris (SAP) and 89 patients to have UAP.

METHODS

Peripheral blood was drawn from the patients. Peripheral blood mononuclear cells (PBMCs) isolated by gradient centrifugation were cultured at a density of 2x106 cells/ml for 24 hours. The supernatants were collected 24 hours after incubation and the granzyme B level was measured by enzyme-linked immunosorbent assay. Polychromic flow cytometric analysis was performed to evaluate the expression of granzyme B in the cells.

RESULTS

Granzyme B production from PBMCs of UAP patients was significantly higher than from those of patients with SAP (39.1 (SEM 6.6) versus 17.0 (SEM 1.8) pg/ml, p<0.05). Granzyme B production from PBMCs increased with the increasing TIMI risk score in UAP patients. The percentage of granzyme B-positive lymphocytes to CD3-positive lymphocytes in UAP patients was significantly higher than in SAP (32.1% (SEM 1.6%) versus 18.4% (SEM 0.9%), p<0.01).

CONCLUSIONS

These results suggest that granzyme B might play an important role in triggering acute coronary events by inducing apoptosis and the degradation of atherosclerotic coronary plaques.

Matrix metalloproteinase-3 and coronary remodelling: implications for unstable coronary disease

OBJECTIVES

Matrix metalloproteinases (MMPs) are plausible candidates for prediction of unstable coronary syndromes. We hypothesised that the MMP-3 polymorphism (- 1171, 5A/6A) would relate to coronary plaque characteristics and unstable clinical presentation.

METHODS AND RESULTS

Forty patients with de novo presentation of coronary artery disease (CAD) were classified into unstable coronary syndrome (n=19) or stable angina pectoris (n=21). On coronary intravascular ultrasound, patients with unstable disease had a greater plaque burden, more positive (outward) coronary remodelling, and all but one were MMP-3 6A allele carriers (p=0.027 compared with stable). The relationship between the 6A allele and unstable presentation was substantiated in a validation cohort of 161 CAD patients (58 stable and 103 unstable) and in the total population of 201 CAD patients (79 stable and 122 unstable, p=0.007), and was independent of conventional risk factors. Furthermore, 6A allele carriers had a higher plasma MMP-3 concentration (15.8+/-12.5 versus 11.7+/-7.2 ng/mL, p=0.01), maximum coronary stenosis on angiography (89+/-15% versus 80+/-23%, p=0.02), plaque area (12.0+/-5.2 versus 7.5+/-3.6 mm(2), p=0.03), percentage plaque burden (82+/-7 versus 71+/-13%, p=0.003), and remodelling ratio (1.03+/-0.23 versus 0.83+/-0.12, p=0.003).

CONCLUSIONS

The MMP-3 6A allele promotes positive coronary remodelling, greater plaque burden, and increased susceptibility to unstable coronary syndromes in humans.

[Clinical implications of relationship between myeloperoxidase and acute coronary syndromes]

OBJECTIVE

To investigate the clinical implications of relationship between myeloperoxidase and acute coronary syndromes (ACS).

METHODS

176 consecutive patients who underwent coronary angiography for coronary atherosclerosis were divided into four groups according to the quartile of MPO Level. The characters and the relationship between MPO and the elements were studied in every group.

RESULTS

(1) ACS rate (36.2%) in the fourth quartile group of MPO level was 6 times higher than that (5.2%) in the first quartile group of MPO level, P < 0.01. (2) Gensini score (65.6 +/- 30.3) in the fourth quartile group of MPO level was significantly higher than that (17.3 +/- 10.2) in the first quartile group (P < 0.01). WBC [(7.7 +/- 1.6) x 10(9)/L] in the fourth quartile group was also significantly higher than that [(6.6 +/- 1.8) x 10(9)/L] in the first quartile group, P < 0.05. (3) When TnI < or = 0.05 ng/ml, MPO level had a positive correlation with Gensini score (r = 0.321, P = 0.002) and WBC (r = 0.230, P = 0.025). (4) Kaplan-meier event rate curve showed that there was a significant difference of the terminus incident (death, no causing death AMI, vessel reestablish and incidence rate of CABG add up) between the groups > or = 62.9 AUU/L and < 62.9 AUU/L of MPO serum level at 6-month follow-up visit (chi(2) = 13.5, P = 0.01).

CONCLUSION

Activity level of MPO in human serum seems a good biomarker for diagnosing and predicting ACS, which may be especially helpful in predicting the risk of myocardial infarction in patients with acute chest pain during 6-month follow up.

Study of leukocytic hydrolytic enzymes in patients with acute stage of coronary heart disease

BACKGROUND

Coronary heart disease (CHD) is a major killer worldwide. Atherosclerosis, which is the basis of CHD, is believed to be an inflammatory disorder. Though various aspects of atherosclerosis are extensively studied, leukocytic hydrolytic enzymes are not studied very well with respect to CHD.

AIM

This study was planned to assess changes associated with leukocytic hydrolases in CHD patients.

SETTING AND DESIGN

A tertiary care hospital; case-control study.

MATERIALS AND METHODS

106 patients with acute myocardial infarction, 60 patients with unstable angina and 45 healthy controls were included in the study. Acid phosphatase, lysozyme, adenosine deaminase (ADA) and cathepsin-G levels were estimated from leukocytes. Reduced glutathione (GSH) and malondialdehyde (MDA) levels were measured.

STATISTICAL ANALYSIS

Statistical comparison of data was done using student's t-test (unpaired). Correlation difference was calculated by using Pearson correlation coefficient.

RESULTS

Significantly higher levels of acid phosphatase, lysozyme, ADA with lower levels of cathepsin G in leukocytes were observed in CHD group. We also found significantly higher levels of serum MDA with lower concentrations of blood GSH in CHD group. In diabetic CHD group, significantly higher levels of leukocytic acid phosphatase, lysozyme, ADA and serum MDA with lower levels of cathepsin G and blood GSH were observed.

CONCLUSIONS

Our study indicates that leukocyte hydrolytic enzymes, mainly acid phosphatase, lysozyme and ADA were more active in CHD patients and may contribute to inflammation related with CHD. Its also indicates that leukocyte cathepsin-G may have antiinflammatory role.

Effects of Glucose-Insulin-Potassium Solution on Cardiac Cytokines and Enzymes

OBJECTIVE

The aim of this study was to assess the effects of glucose-insulin-potassium (GIK) solution on intraoperative cardiac cytokines and cardiac enzymes in coronary artery bypass surgery patients.

METHODS

The study group consisted of 49 patients with unstable angina who required urgent CABG. Patients were randomized to a GIK (n = 25) or a non-GIK (n = 24) group. The GIK group received 500 ml of 30 % dextrose solution, containing 100 IU insulin and 80 mEq of potassium, at a rate of 1 ml x kg (-1) x h (-1). The control group received an equivalent rate of 5 % dextrose. Serum cytokine levels were measured in blood samples obtained from coronary sinus blood samples. Cardiac enzymes such as creatinin kinase (CK), myocardial band of creatinin kinase (CK-MB) and Troponin-T were measured immediately after operation and at 6, 24 and 48 hours after operation.

RESULTS

No patient in the two groups developed ECG or enzyme changes after surgery suggestive of acute myocardial infarction and myocyte damage. Interleukin-10 concentrations were greater in the GIK group (31.10 +/- 3.36) than in the non-GIK group (19.10 +/- 4.32) ( P < 0.05).

CONCLUSION

We conclude that a GIK solution increases the serum cardioprotective interleukin-10 concentrations in CABG patients with unstable angina pectoris. We found no significant difference in any of the other parameters respecting myocyte damage.

Plasma matrix metalloproteinase-3 level is an independent prognostic factor in stable coronary artery disease

BACKGROUND

Recent evidence suggests the important role of matrix metalloproteinases (MMPs) in the progression of atherosclerosis and development of clinical events. We assessed the prognostic value of different plasma MMPs in patients with stable coronary artery disease (CAD).

MATERIALS AND METHODS

A total of 165 consecutive nondiabetic patients with angiographically significant CAD (n = 150) or normal coronary angiograms despite exercise-induced myocardial ischemia (cardiac syndrome X, n = 15) and 17 normal subjects were evaluated. In each subject, plasma inflammatory markers including high sensitivity C-reactive protein (hsCRP) and MMP-2, 3 and 9 were measured. In CAD patients, major cardiovascular events including cardiac death, nonfatal myocardial infarction, unscheduled coronary revascularization and hospitalization as a result of unstable angina were prospectively followed up for more than 6 months.

RESULTS

Plasma levels of MMPs were significantly higher in CAD patients than in those with cardiac syndrome X and in normal subjects (MMP-2: 914.76 +/- 13.20 vs. 830.79 +/- 31.95 vs. 783.08 +/- 28.40 ng mL(-1), P = 0.002; MMP-3: 129.59 +/- 4.21 vs. 116.86 +/- 8.09 vs. 91.71 +/- 9.55 ng mL(-1), P = 0.011; MMP-9: 31.42 +/- 2.84 vs. 11.40 +/- 5.49 vs. 6.71 +/- 2.89 ng mL(-1), P = 0.006). In CAD patients, there were 48 major cardiovascular events during a mean follow-up period of 17.74 +/- 0.85 months. The numbers of diseased vessels (HR = 2.19, 95% CI 1.20-1.02, P = 0.011), plasma hsCRP (HR = 2.21, 95% CI 1.18-4.11, P = 0.013) and MMP-3 level (HR = 2.46, 95% CI = 1.15-5.28, P = 0.021) were associated with the development of cardiovascular events. However, only the plasma MMP-3 level was an independent predictor of the adverse events in CAD patients (HR = 2.47, 95% CI 1.10-5.54, P = 0.028).

CONCLUSIONS

Plasma MMP levels were increased in CAD patients. Plasma MMP-3 level, rather than hsCRP, was an independent prognostic marker for future cardiovascular events, suggesting its potential role in risk stratification and clinical management of stable CAD.

Platelet-activating factor acetylhydrolase activity indicates angiographic coronary artery disease independently of systemic inflammation and other risk factors: the Ludwigshafen Risk and Cardiovascular Health Study

BACKGROUND

Platelet-activating factor acetylhydrolase (PAF-AH), also denoted as lipoprotein-associated phospholipase A2, is a lipoprotein-bound enzyme that is possibly involved in inflammation and atherosclerosis. This study investigates the relationship of PAF-AH activity to angiographic coronary artery disease (CAD), the use of cardiovascular drugs, and other established risk factors.

METHODS AND RESULTS

PAF-AH activity, lipoproteins, sensitive C-reactive protein (sCRP), fibrinogen, serum amyloid A, and white blood cell count were determined in 2454 subjects with angiographically confirmed CAD and in 694 control subjects. PAF-AH activity was highly correlated with LDL cholesterol (r=0.517), apolipoprotein B (r=0.644), and non-HDL cholesterol (r=0.648) but not with sCRP or fibrinogen. PAF-AH activity was lower in women than in men and was affected by the intake of lipid-lowering drugs (-12%; P<0.001), aspirin (-6%; P<0.001), beta-blockers (-6%; P<0.001), and digitalis (+7%; P<0.001). Unlike sCRP, fibrinogen, and serum amyloid A, PAF-AH activity was not elevated in unstable angina, non-ST-elevation myocardial infarction, or ST-elevation myocardial infarction. When nonusers of lipid-lowering drugs were examined, PAF-AH activity was associated with the severity of CAD and the number of coronary vessels with significant stenoses. In individuals not taking lipid-lowering drugs and after adjustment for use of aspirin, beta-blocker, and digitalis, the odds ratio for CAD associated with increasing PAF-AH activity was 1.39 (95% CI 1.26 to 1.54, P<0.001), a finding that was robust against further adjustments.

CONCLUSIONS

PAF-AH activity is not an indicator of the systemic inflammation that accompanies acute coronary syndromes. PAF-AH activity is affected by a number of cardiovascular drugs; however, after such medication use was accounted for, PAF-AH activity was associated with angiographic CAD, complementary to sCRP and independently of established risk factors such as LDL cholesterol.

Clinical Association between Renal Insufficiency and Positive Troponin I in Patients with Acute Coronary Syndrome

BACKGROUND

Whether renal insufficiency (RI) influences troponin levels in patients with acute coronary syndromes (ACS) is controversial. We attempted to determine whether there is an association between RI and troponin I (TnI) elevation in patients presenting with ACS.

METHODS

We studied 764 consecutive patients with ACS admitted to our institution from January 1999 to June 2000. Patients were identified prospectively and data were collected through chart review of all cases with an admission diagnosis of ACS. In order to assess the relationship of TnI and RI, we calculated the creatinine clearance (Cr-Cl) for all patients. We conducted an analysis of variance comparing TnI in quintiles of patients with lowest to highest Cr-Cl.

RESULTS

Among 764 patients, 173 patients had a discharge diagnosis of ST elevation myocardial infarction and 591 had non-ST elevation myocardial infarction. There was no correlation between peak TnI levels and renal function as measured by Cr-Cl in the entire cohort with ACS and in the subgroups with ST elevation myocardial infarction and non ST elevation myocardial infarction.

CONCLUSIONS

This large cohort study demonstrates that there appears to be no association between RI and positive TnI in patients with ACS.

Increased serum concentrations of soluble CD95/Fas and caspase 1/ICE in patients with acute angina

OBJECTIVES

To investigate the expression of death inducing receptors in the sera of patients with stable and unstable angina.

DESIGN

80 consecutive patients with stable (n = 40) or unstable (n = 40) angina pectoris were studied. Serum concentrations of soluble CD95 (sCD95), soluble CD95 ligand (sCD95L; CD178), tumour necrosis factor (TNF) alpha, soluble TNFalpha receptor type 1 (sTNFR1), and interleukin 1beta converting enzyme (ICE; caspase 1) were measured by enzyme linked immunosorbent assay (ELISA).

RESULTS

Significant increases in the concentrations of sCD95 and ICE (p < 0.001 and p < 0.023, respectively) were found in the serum from patients with unstable angina relative to those with stable angina. There were no significant differences in the concentrations of sCD95L, TNF alpha, and sTNFR1 between the groups.

CONCLUSIONS

These data provide the first evidence that sCD95 and ICE are important serological markers that may help to discriminate between stable and unstable angina. This observation may warrant further clinical study to elucidate the clinical impact of sCD95 and ICE in acute coronary syndromes.

Comparison of different cardiac markers in monitoring percutaneous coronary interventions with frequent use of stents and gpIIbIIIa-antagonists

Studies from the early 1990s found elevations of creatine kinase (CK) and its isoform CK-MB in 5-30% of patients after PCI, indicating minor myocardial damage. Less is known about the influence of modern improved PCI-techniques on the frequency of elevated cardiac markers and the correlation between different commonly used markers, especially cardiac troponins. From 1997 to 2001, 1486 patients undergoing PCI during the regular working hours were included in the prospective "Ludwigshafen Infarctlet Registry". Myocardial infarction in the past 48 hours was an exclusion criterion. Clinical and procedural data were documented. Follow-up data were obtained from discharge up to one year. PCI-related elevations of troponin T were found in 18%, of total-CK in 11%, of CK-MB in 33% and of myoglobin in 23% of cases. The correlation between the different markers was poor. Compared with troponin T, other markers showed low sensitivity (total-CK 58%, CK-MB 27%, myoglobin 22%) and, especially total-CK, low specificity. Stenting, side branch occlusion or major dissection, complex lesion morphology, gpIIbIIIa-antagonist application, proximal stenosis and unstable angina were independent predictors of an elevated troponin T in multivariate analysis. Due to this weak correlation between more specific and sensitive troponins and the other markers, troponins are preferred in monitoring after PCI. In addition to lesion characteristics, particularly stenting is associated with an increased rate of elevated troponin.

Superoxide generation in directional coronary atherectomy specimens of patients with angina pectoris: important role of NAD(P)H oxidase

OBJECTIVE

NADH/NADPH oxidase is an important source of reactive oxygen species (ROS) in the vasculature. Recently, we demonstrated that p22(phox), an essential component of this oxidase, was expressed in human coronary arteries and that its expression was enhanced with the progression of atherosclerosis. The present study was undertaken to investigate its functional importance in the pathogenesis of coronary artery disease. For this aim, the expression of p22(phox), the distribution of oxidized low density lipoprotein (LDL), and the generation of ROS in directional coronary atherectomy (DCA) specimens were examined.

METHODS AND RESULTS

DCA specimens were obtained from patients with stable or unstable angina pectoris. The distribution of p22(phox) and of oxidized LDL was examined by immunohistochemistry. The generation of superoxide in DCA specimens was assessed by the dihydroethidium method and lucigenin-enhanced chemiluminescence. ROS were closely associated with the distribution of p22(phox) and oxidized LDL. Not only inflammatory cells but also smooth muscle cells and fibroblasts generated ROS. There was a correlation between ROS and the expression of p22(phox) or oxidized LDL. The generation of ROS was significantly higher in unstable angina pectoris compared with stable angina pectoris.

CONCLUSIONS

ROS generated by p22(phox)-based NADH/NADPH oxidase likely mediate the oxidative modification of LDL and might play a major role in pathogenesis of atherosclerotic coronary artery disease.

Suppression of coronary artery spasm by the Rho-kinase inhibitor fasudil in patients with vasospastic angina

BACKGROUND

Increased activity of Rho-kinase causes hypercontraction of vascular smooth muscle and has been implicated as playing a pathogenetic role in divergent cardiovascular diseases such as coronary artery spasm. We examined whether an intracoronary infusion of fasudil, a selective Rho-kinase inhibitor, would attenuate coronary vasoconstrictor responses to acetylcholine (ACh) in patients with vasospastic angina.

METHODS AND RESULTS

We studied 20 consecutive patients in whom coronary artery spasm was provoked by intracoronary ACh. The patients underwent a second ACh challenge after pretreatment with intracoronary saline (n=5) or fasudil (n=15; 300 microg/min for 15 minutes). Angina and coronary vasospasm were reproducibly induced by the second testing in patients who received saline. In contrast, fasudil markedly attenuated the coronary constriction induced by ACh (P<0.001) and prevented the occurrence of chest pain and ischemic ECG changes in all treated patients (both P<0.01 versus saline). Fasudil, at the dose used in this study, did not significantly change systemic hemodynamics or baseline coronary blood flow.

CONCLUSIONS

Fasudil was effective in preventing ACh-induced coronary artery spasm and resultant myocardial ischemia in patients with vasospastic angina. We suggest that this Rho-kinase inhibitor may be a novel therapeutic intervention to treat ischemic coronary syndromes caused by coronary artery spasm.

Secretory type II phospholipase A(2) binds to ischemic myocardium during myocardial infarction in humans

OBJECTIVE

An increase of circulating secretory Phospholipase A(2) (sPLA(2)) is a risk factor for coronary artery disease. We hypothesized that this reflects participation of sPLA(2) in local inflammatory reactions ensuing in ischemic myocardium. Therefore, we studied the course of circulating sPLA(2), in patients with acute myocardial infarction (AMI) or unstable angina pectoris (UAP), and investigated the presence of sPLA(2) in infarcted myocardial tissue.

METHODS

Plasma samples of 107 patients with AMI or UAP, collected on admission and at varying intervals thereafter, were tested for the presence of sPLA(2) and C-reactive protein (CRP). Cumulative release values of these parameters were calculated, which allowed for comparison of the results rearranged in time according to the onset of symptoms. By immunohistochemistry we studied the presence of sPLA(2) and CRP in myocardial tissue of 30 patients who died subsequent to AMI.

RESULTS

Levels of sPLA(2) became elevated during the disease course in 66 of the 87 patients with AMI, and were higher than those of the patients with UAP of whom 8 of the 20 had elevated levels. By immunohistochemistry sPLA(2) was found to be localized in the infarcted myocardium, particularly in its borderzone, from 12 h after the onset of AMI. Positive staining for sPLA(2) was more extensive than that for CRP.

CONCLUSIONS

The localization pattern of sPLA(2) in infarcted myocardium as well as its plasma course, in relation to those of CRP, are in line with a supposed pro-inflammatory role during AMI for sPLA(2) as a generator of lysophospholipids serving as ligands for CRP.

Role of coenzyme Q10 in chronic heart failure, angina, and hypertension

PURPOSE

Coenzyme Q10 (CoQ10) has a pathophysiologic role in many disease states. The purpose of this review is to provide recommendations regarding the safety, efficacy, and dosing of CoQ10 in the management of chronic heart failure (CHF), angina, and hypertension.

DATA SOURCES

Literature pertaining to the safety and efficacy of CoQ10 specifically in cardiovascular indications was reviewed. We used relevant clinical trials, articles, reviews, and letters that were selected from a literature search of the MEDLINE database (1974-2000), Micromedex Healthcare Series, and the Natural Medicines Comprehensive Database.

FINDINGS

Coenzyme Q10 administered orally has favorable actions in the described cardiovascular conditions and appears to be safe and well tolerated in the adult population. Issues concerning optimum target dosages, potential interactions, monitoring parameters, and the role of CoQ10 as a monotherapeutic agent need to be investigated further. Favorable effects of CoQ10 on ejection fraction, exercise tolerance, cardiac output, and stroke volume are demonstrated in the literature; thus, the use of CoQ10 as adjuvant therapy in patients with CHF may be supported.

CONCLUSIONS

Coenzyme Q10 therapy in angina and hypertension cannot be substantiated until additional clinical trials demonstrate consistent beneficial effects. However, CoQ10 may be recommended as adjuvant therapy in selected patients with CHE At this time, CoQ10 should not be recommended as monotherapy or first-line therapy in any disease state.

Accuracy of biomarkers to diagnose acute cardiac ischemia in the emergency department: a meta-analysis

STUDY OBJECTIVE

We sought to evaluate quantitatively the evidence on the diagnostic performance of presentation and serial biochemical markers for emergency department diagnosis of acute cardiac ischemia (ACI), including acute myocardial infarction (AMI) and unstable angina.

METHODS

We conducted a systematic review and meta-analysis of the English-language literature published between 1966 and December 1998. We examined the diagnostic performance of creatine kinase, creatine kinase-MB, myoglobin, and troponin I and T testing. Diagnostic performance was assessed by using estimates of test sensitivity and specificity and was summarized by summary receiver-operating characteristic curves.

RESULTS

Only 4 studies were found that evaluated all patients with ACI; 73 were found that focused only on a diagnosis of AMI. To diagnose ACI, presentation biomarker tests had sensitivities of 16% to 19% and specificities of 96% to 100%; serial biomarker tests had sensitivities of 31% to 45% and specificities of 95% to 98%. Considering only the diagnosis of AMI, presentation biomarker tests had summary sensitivities of 37% to 49% and summary specificities of 87% to 97%; serial biomarker tests had summary sensitivities of 79% to 93% and summary specificities of 85% to 96%. Variation of test sensitivity was best explained by test timing. Longer symptom duration or time between serial tests yielded higher sensitivity.

CONCLUSION

The limited evidence available to evaluate the diagnostic accuracy of biomarkers for ACI suggests that biomarkers have very low sensitivity to diagnose ACI. Thus, biomarkers alone will greatly underdiagnose ACI and will be inadequate to make triage decisions. For AMI diagnosis alone, multiple testing of individual biomarkers over time substantially improves sensitivity, while retaining high specificity, at the expense of additional time. Further high-quality studies are needed on the clinical effect of using biomarkers for patients with ACI in the ED and on optimal timing of serial testing and in combination with other tests.

Enzymatic oxidant and antioxidants of human blood platelets in unstable angina and myocardial infarction

In ischaemic heart conditions we report a remarkable increase in platelet xanthine oxidase activity and rise in the levels of malondialdehyde (MDA) with concomitant decrease in the activities of free radical scavenging enzymes - superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. The increased levels of free radical generating system and MDA and lowered levels of free radical scavenging systems seem to have critical role in ischaemic heart conditions.

[Matrix metalloproteinase-1 and coronary atheroslerotic plaque rupture]

OBJECTIVE

To investigate the relationship between matrix metalloproteinase-1 (MMP-1) and coronary atherosclerotic plaque rupture, and the cellular source of MMP-1 within the plaques.

METHODS

42 cases, among which 20 died of acute myocardial infarction, 10 with unstable angina history and 12 with stable angina history but died of other diseases, were selected. All the branch of coronary arteries were examined, parts of the segments were selected for immunohistochemical staining, 5 markers against alpha-smooth muscle actin, CD20, CD45RO, CD68 and MMP-1 were performed.

RESULTS

Plaque rupture and thrombosis were found in almost all the cases of acute myocardial infarction and unstable angina. But in the cases of stable angina, the majority of the plaques were stable ones. The expression of MMP-1 in the ruptured plaques were stronger than the unruptured ones (t = -8.07, P < 0.05); Positive relationship was also noted between the expression of CD68 and MMP-1 (r = 0.75, P < 0.05).

CONCLUSION

Macrophages are capable of degrading extracellular matrix by secreting MMP-1; Enhanced secretion of MMP-1 within the coronary atherosclerotic plaques has significant relationship with plaque rupture.

Ingenuous interpretation of elevated blood levels of macromolecular markers of myocardial injury: a recipe for confusion

Several assumptions about elevations of macromolecular markers of myocardial injury in blood require critical consideration. The dichotomy of modest, persistent elevations of troponins I and T as prognostic factors in patients with unstable angina and absent elevations of isoenzymes of creatine kinase is presently unexplained. Factors influencing the appearance of macromolecular markers of myocardial injury in blood are considered, including the need to estimate baseline values, to consider elevations as deviations from baseline rather than simply points within a distribution of baseline values in normal subjects, to recognize operative biochemical and physiologic determinants of marker release from injured myocytes and washout and to take into account the influence of apoptosis. Elucidation and consideration of mechanisms underlying the appearance of specific macromolecular markers in blood appear likely to improve diagnosis and explain the prognostic power of the troponins in patients with unstable angina. Detection of proteolytic breakdown products of troponins in blood is likely to explain the modest, persistent elevations seen in some patients with unstable angina and their prognostic implications.

Levels of glutathione reductase and glutathione peroxidase of human platelets in unstable angina and myocardial infarction

Levels of glutathione peroxidase and glutathione reductase were measured in the platelets of 30 patients, 10 of them affected by unstable angina, 10 of them reperfused after myocardial infarction and 10 matched healthy controls. The specific activities of both the enzymes were lowered in both group of patients. Glutathione reductase activity resulted markedly lowered.

Platelet aggregatory response to platelet activating factor (PAF), ex vivo, and PAF-acetylhydrolase activity in patients with unstable angina: effect of c7E3 Fab (abciximab) therapy

OBJECTIVE

Platelet activation and aggregation is a dominant feature in the pathophysiology of unstable angina. The final step of platelet aggregation is mediated through the platelet integrin glycoprotein IIb/IIIa (GP IIb/IIIa), while abciximab (ReoPro) is one of the most potent inhibitors of this receptor. Platelet-activating factor (PAF) is a potent platelet agonist which is degraded and inactivated by PAF-acetylhydrolase (PAF-AH). The plasma form of PAF-AH is associated with lipoproteins. We studied the platelet response to the aggregatory effect of PAF, ex vivo, in relation to the plasma PAF-AH activity in 32 patients with unstable angina, as well as the effect of abciximab therapy on the above parameters.

METHODS

Thirty two patients with unstable angina and 25 sex- and age-matched healthy controls participated in the study. On the day of admission (day 1) 17 patients received a bolus of abciximab (0.25 mg/kg) followed by a 12-h infusion (10 micrograms/min). Platelet aggregation to both PAF and ADP, in platelet rich plasma, was successively studied in both patients receiving abciximab or remaining untreated. The plasma and HDL-associated PAF-AH activity was also determined at the same times.

RESULTS

In the untreated patients, the PAF EC50 values were significantly lower on the day of admission, whereas the maximal percentage of aggregation was significantly higher compared to controls (p < 0.01 for both comparisons). Similar behaviour of the platelets was observed in the aggregatory effect of ADP. This aggregatory response was not significantly altered 4 days, 7 days or 1 month afterwards. In the 17 patients who received abciximab, platelet aggregation to both PAF and ADP was inhibited by 90 +/- 5 and 96 +/- 3%, respectively, 1 h after bolus. At 2 and 3 days after treatment, platelet aggregation to both agonists was significantly recovered being similar to controls. However, it was fully restored 6 days after bolus, still being significantly higher compared to controls (p < 0.01 for PAF and p < 0.003 for ADP). The total plasma PAF-AH activity in both patient groups was not different from that of controls, whereas the HDL-associated PAF-AH activity was significantly lower. The total plasma or HDL-associated enzyme activity was not altered at any time interval studied, and it was not influenced by abciximab.

CONCLUSIONS

The increased aggregatory response of platelets to PAF and the low plasma levels of HDL-cholesterol and HDL-associated PAF-AH activity in patients with unstable angina may contribute to the severe atherosclerosis and to acute thrombosis found in these patients. Abciximab therapy may protect platelets from PAF action in vivo the first days after drug administration, but it fails to permanently restore the enhanced aggregatory response observed.

Expression of inducible nitric oxide synthase in human coronary atherosclerotic plaque

OBJECTIVE

Macrophages in atherosclerotic plaque may express the inducible isoform of NO synthase (iNOS), which produces large amounts of NO. On one hand, the production of NO can be protective by its vasodilatory, antiaggregant and antiproliferative effects. On the other hand, the formation of peroxynitrite from NO may favour vasospasm and thrombogenesis. In this study, we investigated whether iNOS is present in human coronary atherosclerotic plaque, and we correlated these data with the clinical instability of the patients.

METHODS

Fragments were retrieved by coronary atherectomy from 24 patients with unstable angina and 12 patients with stable angina. The presence of macrophages, and the production of TNF alpha, iNOS and nitrotyrosine were detected by immunocytochemistry.

RESULTS

Macrophage clusters were found in 67% of stable patients and 87% of patients with unstable angina (NS). TNF alpha was expressed in about 50% of cases in both groups. iNOS was not expressed in fragments from stable patients but was found in macrophages from 58% of unstable patients (P < 0.001). The expression of iNOS was associated with the presence of nitrotyrosine residues, a marker of peroxynitrite formation. Expression of iNOS was correlated both with complaints of angina at rest (P < 0.05) and with the presence of thrombus at morphological examination (P < 0.001).

CONCLUSION

The expression of iNOS may be induced in human coronary atherosclerotic plaque and is associated with different factors of instability.

Troponin T and creatinine kinase isoenzyme MB mass in the diagnosis of myocardial infarction

The aim of this study was to compare troponin T (TnT) and creatine kinase isoenzyme MB mass (CK-MBm) with conventional enzymes, ie CK, CK-MB activity and lactate dehydrogenase isoenzyme 1, in the diagnosis of myocardial infarction (MI). 624 patients (351 men and 273 women, median age 69 years) were admitted to hospital with suspicion of an acute coronary heart disease event. TnT was elevated (> 0.10 microg/L) in 100%, CK-MBm (> 5.0 microg/L) in 99%, and both markers in 99% of the 89 patients with the diagnosis of a definite MI according to modified FINMONICA criteria. In the 60 patients with the diagnosis of a probable MI, TnT was elevated in 65%, CK-MBm in 67% and both markers in 60%. In the patients with unstable coronary artery disease (unstable angina or prolonged chest pain attack) and conventional enzymes within normal limits, TnT was elevated in 14%, CK-MBm in 17% and both markers in 9%. The use of TnT and CK-MBm did not lead to a major change in the diagnostics of definite MI. However, TnT and CK-MBm did not confirm the diagnosis of probable MI in one-third of the events. These new markers revealed a myocardial injury in about 15% of those patients who had unstable coronary artery disease and conventional enzymes within normal limits.

Peripheral blood levels of matrix metalloproteases-2 and -9 are elevated in patients with acute coronary syndromes

OBJECTIVES

This study was sought to investigate whether peripheral blood levels of matrix metalloproteases (MMPs) are affected in patients with acute coronary syndromes (ACS).

BACKGROUND

Synthesis of MMPs has been reported in coronary atherosclerotic lesions in patients with unstable angina (UA), suggesting a pathogenic role of MMPs in the development of ACS.

METHODS

Using sandwich enzyme immunoassay, serum MMP-2 and plasma MMP-9 were measured in 33 patients with ACS (22 with acute myocardial infarction [AMI], 11 with UA), 17 with stable effort angina (EA) and 17 normal control subjects.

RESULTS

Serum MMP-2 in patients with UA and AMI on day 0 was two times greater than that in control subjects, and patients with EA showed higher MMP-2 levels than those in control subjects. Plasma MMP-9 in patients with UA and AMI on day 0 was elevated by threefold and twofold versus that in control subjects, respectively. In patients with UA and AMI who underwent medical treatment (n = 11 and 13, respectively), MMP-2 elevation was sustained until day 7. In patients with UA, MMP-9 elevation on day 0 was followed by a gradual decrease toward the control range up to day 7. Some patients with AMI showed a transient MMP-9 elevation with a peak on day 3, whereas in others, MMP-9 levels were significantly elevated on day 0 and remained higher than those in control subjects up to day 3.

CONCLUSIONS

Serial changes in serum MMP-2 and plasma MMP-9 were documented in patients with ACS. These findings provide an insight into the molecular mechanism of plaque destabilization.

Differences between local investigator and core laboratory interpretation of the admission electrocardiogram in patients with unstable angina pectoris or non-Q-wave myocardial infarction (a Thrombin Inhibition in Myocardial Ischemia [TRIM] substudy)

The present study compares the on-site interpretation of an admission electrocardiogram (ECG) with core laboratory results in a large, multicenter trial of 516 patients diagnosed with unstable angina pectoris or non-Q-wave myocardial infarction. The local investigators evaluated the admission ECG regarding ST-T changes before the ECGs were sent to the core laboratory for blinded interpretation. The strength of agreement between the observations was described by kappa statistics. There was a poor agreement regarding identification of ST-segment elevation, with 17 patients identified by the local investigator versus 92 by the core laboratory (kappa = 0.05). There was a fair agreement on ST-segment depression with 158 patients diagnosed on-site versus 64 by the core laboratory (kappa = 0.38). Identification of T-wave inversion demonstrated good agreement with 306 patients diagnosed on-site versus 280 by the core laboratory (kappa = 0.63). A moderate agreement regarding identification of a normal ECG was found with 101 patients on-site versus 135 in the core laboratory (kappa = 0.42). Independent variables, including peak creatine kinase-MB and 30-day outcome, were more closely related to core laboratory results than the local investigator's interpretation of the admission ECG. Thus, in the present study, considerable differences were demonstrated between the on-site interpretation of the admission ECG and the blinded evaluation performed in the core laboratory regarding relatively simple electrocardiographic variables. The results suggest that more widespread use of independent evaluation of clinical data should be incorporated in future clinical trials.

Cardiac troponin I as a predictor of major cardiac events in emergency department patients with acute chest pain

OBJECTIVES

We sought to evaluate the diagnostic and prognostic value of cardiac troponin I (cTnI) in emergency department (ED) patients with chest pain.

BACKGROUND

Although cTnI has been shown to correlate with an increased risk for complications in patients with unstable angina, the prognostic significance of this assay in the heterogeneous population of patients who present to the ED with chest pain is unclear.

METHODS

cTnI and creatine kinase-MB fraction (CK-MB) mass concentration were collected serially during the first 48 h from onset of symptoms in 1,047 patients > or =30 years old admitted for acute chest pain. Sensitivity, specificity and receiver operating characteristic curves were calculated for cTnI and CK-MB collected in the first 24 h.

RESULTS

The sensitivity, specificity and positive predictive value of cTnI for major cardiac events were 47%, 80% and 19%, respectively. Among patients were who ruled out for myocardial infarction, cTnI was elevated in 26% who had major cardiac complications compared with 5% for CK-MB; the positive predictive value for an abnormal cTnI result was 8%. Elevated cTnI in the presence of ischemia on the electrocardiogram was associated with an adjusted odds ratio of 1.8 (95% confidence interval 1.1 to 2.9) for major cardiac events within 72 h. Among patients without a myocardial infarction or unstable angina, cTnI was not an independent correlate of complications.

CONCLUSIONS

In patients presenting to the ED with acute chest pain, cTnI was an independent predictor of major cardiac events, However, the positive predictive value of an abnormal assay result was not high in this heterogeneous cohort.

[Biochemical markers enable early diagnosis of myocardial damage]

Diagnosis of myocardial damage based on early measurement of biochemical markers is becoming an increasingly important guide in the management and treatment of suspected coronary artery disease. The new, more sensitive and/or specific markers myoglobin, CK-MB (creatine kinase and its cardiospecific isoenzyme), and the troponins T and I, are reviewed in the article, new rapid analytical tests are discussed, and modified sampling routines proposed. The combination of a marker with high early sensitivity and a marker with a broad time window and high specificity, together with modified sampling routines and analysis of whole blood can yield a reliable diagnosis within minutes or (3-6) hours of the patient's presentation. Moreover, together with other non-invasive methods, use of the markers of myocardial injury enables rapid and reliable risk analysis.

Analytical aspects of the automated CKMB1,2 and CKMM1,2,3 isoform determination and its relation to other biochemical markers

The automated (CK)MB1,2/MM1,2,3 isoform measurement, based on electrophoresis, has been simplified to the point that it has become possible to perform this analysis on a 24-h routine basis. We studied analytical aspects of this analysis and its clinical relevance in relation to other biochemical markers (CK total, CKMB activity, CKMB mass, myoglobin, Troponin I and Troponin T) in patients with acute myocardial infarction (AMI), patients with unstable angina pectoris (UAP), and healthy donors. Furthermore, the additional significance of the analysis was evaluated in patients with clinically unexpected, raised CKMB/CK total activities. The storage of serum at 4 degrees C does not influence the MB2/MB1 ratios, whereas storage at 20 degrees C changes them significantly. MM3/MM1 and normal MB2/MB1 ratios show lower coefficients of variation than increased MB2/MB1 ratios. Between 2 and 30 h after myocardial tissue damage, AMI patients showed a characteristic change in CK isoform patterns. At a mean time of 3.6 h after the onset of symptoms we found raised MB2/MB1 ratios in 94% of these patients. With the information of the CK isoform analysis unexpected abnormal CK activities could explained by CK macro enzymes (Ig-bound and mitochondrial), insufficient CK clearance capacity, enzyme activities 4 h after (re-)infarction and raised CK activity 15 h after skeletal muscle damage. We conclude that the CK isoforms are relatively simply to assess; they are adequate tools with which to indicate the CK kinetics over a period lasting between 2 and 30 h after tissue damage with a single blood sample and a single analysis; the CK isoform analysis has additional value in explaining inappropriate CKMB/CK total activities, and the MB2/MB1 ratios show to be one of the best early parameters for discriminating patients with AMI on admission to hospital.

5'-nucleotidase and adenosine deaminase activities in blood of patients with unstable angina pectoris

During ischaemia and hypoxia adenosine is released from cardiac cells. Adenosine is the end product of 5'-nucleotidase activity. We were interested in how this enzyme activity in plasma of patients with unstable angina pectoris, causes short-term ischaemia. 5'-Nucleotidase activity in plasma was determined using a standard diagnostic kit from Sigma. Furthermore, we studied the activity of adenosine deaminase in plasma, granulocytes, lymphocytes and erythrocytes by the methods of Hopkinson [1]. It was found that 5'-nucleotidase activity was increased by about 43% in plasma. The activity of adenosine deaminase (ADA) in plasma increased by 6%, but in granulocytes, lymphocytes and erythrocytes decreased by about 24, 19 and 10.6%, respectively. We concluded that a large increase in 5'-nucleotidase activity may be caused by activation of 5'-ectonucleotidase in blood cells by ischaemia. However, the decrease in ADA activity in blood cells may be associate with the adenosine metabolism.

The angiotensin converting enzyme genetic polymorphism in acute coronary syndrome--ACE polymorphism as a risk factor of acute coronary syndrome

The deletion polymorphism of angiotensin converting enzyme (ACE) genotype has been reported as an independent risk factor for the development of myocardial infarction (MI). However there are conflicting data showing no relationship between the ACE genotype and coronary artery disease. The present study was performed to investigate the correlation between ACE genetic polymorphism and acute coronary syndrome by comparing the distribution of ACE genotypes and ACE activities in patients with acute MI and unstable angina with those in control group. The frequency of genotype DD was significantly higher in patients with acute coronary syndrome than in controls. Logistic regression analysis showed that ACE polymorphism affected the development of acute coronary syndrome in recessive pattern of D allele. When we divided the patients into MI and unstable angina groups, the frequencies of genotype DD and D allele were significantly higher in unstable angina group than in MI or control groups. In the patients with MI, the frequency of D allele was significantly higher in patients without previous angina than in those with previous angina. There was no significant difference in ACE genotype or allelic frequency according to the severity of coronary lesions. The ACE genotype was associated with marked differences of ACE activity, but there was no difference between the patient and control groups for each genotype. In conclusion, the genotype DD of ACE gene associated with acute coronary syndrome, but not with the severity of coronary artery lesion. These results showed that the genotype DD of ACE gene might be associated with acute coronary syndrome by another mechanism rather than the coronary atherosclerosis.

Serial creatine kinase-MB results are a sensitive indicator of acute myocardial infarction in chest pain patients with nondiagnostic electrocardiograms: the second Emergency Medicine Cardiac Research Group Study

OBJECTIVE

To determine the test performance characteristics of serial creatine kinase-MB (CK-MB) mass measurements for acute myocardial infarction (MI) in patients presenting to the ED with chest pain and nondiagnostic ECGs.

METHODS

A prospective, observational test performance study was conducted. Hemodynamically stable patients aged > or = 25 years with chest discomfort, but without ECGs diagnostic for MI, were enrolled at 7 university teaching hospitals. Presenting ECGs showing > 1-mV ST-segment elevation in > or = 2 electrically contiguous leads were considered diagnostic for MI; patients with diagnostic ECGs on presentation were excluded. Real-time, serial CK-MB mass levels were obtained using a rapid serum immunochemical assay at the time of ED presentation (0-hour) and 3 hours later (3-hour). The following testing schemes were evaluated for their sensitivity and specificity for detection of MI during patient evaluation in the ED: 1) an elevated (> or = 8 ng/mL) presenting CK-MB level; 2) an elevated presenting and/or 3-hour CK-MB level; 3) a significant increase (i.e., > or = 3 ng/mL) within the range of normal limits for CK-MB concentrations during the 3-hour period (delta CK-MB); and/or 4) development of ST-segment elevation during the 3 hours (second ECG).

RESULTS

Of the 1,042 patients enrolled, 777 (74.6%) were hospitalized, including all 67 MI patients (8.6% of admissions). As a function of duration of time in the ED, the test performance characteristics of serial CK-MBs for MI (and cumulative data for the additional ECG) were: [table: see text] The 0-hour to 3-hour CK-MB positive and negative predictive values were 52% to 55% and 96% to 99%, respectively. The sensitivities of serial CK-MB results as a function of the interval following chest discomfort onset were: [table: see text]

CONCLUSION

Serial CK-MB monoclonal antibody mass measurements in the ED can identify MI patients with initially nondiagnostic ECGs. CK-MB sensitivity significantly increases over 3 hours of observation of stable chest discomfort patients in the ED; it also increases as a function of the total interval from onset until enzyme measurement.

Usefulness of positive troponin-T and negative creatine kinase levels in identifying high-risk patients with unstable angina pectoris

Troponin-T was measured in patients with chest pain and negative creatine phosphokinase-MB isoenzymes. Patients with elevated troponin-T had a significantly greater risk of cardiac events over the next 6 months than patients with normal troponin-T.

Effect of magnesium sulphate in patients with unstable angina. A double blind, randomized, placebo-controlled study

AIMS

Administration of intravenous magnesium sulphate has been shown to be protective during acute myocardial ischaemia and it may therefore have beneficial effects in unstable angina. The purpose of this study was to assess the effects of a 24-h infusion of magnesium in patients with unstable angina.

METHODS AND RESULTS

Patients who presented with unstable angina with electrocardiographic changes were randomized to receive a 24-h intravenous infusion of magnesium or placebo within 12 h of admission. The primary endpoint was myocardial ischaemia, as assessed by 48 h Holter monitoring. Resting 12-lead ECGs, creatine kinase-MB release and urinary catecholamines were also assessed. Patients were followed for 1 month. Thirty-one patients received magnesium sulphate and 31 placebo. Baseline characteristics and extent of coronary disease were similar in both groups. On 48 h Holter monitoring, 14 patients (50%) had transient ST segment shifts in the magnesium group vs 12 patients (46%) in the placebo group. However, there were fewer ischaemic episodes in the magnesium group (51 vs 101, P < 0.001) and there was a trend towards an increase in the total duration of ischaemia in the placebo group compared to the magnesium group in the second 24 h (2176 min vs 719 min respectively, P = 0.08). Regression of T wave changes on the 24 h ECG occurred more frequently in patients who received magnesium compared to those treated with placebo (11 patients vs 0 patients respectively, P < 0.005). Creatine kinase-MB release was significantly less at 6 and 24 h in patients who received magnesium compared to those treated with placebo. Catecholamine excretion was lower in patients treated with magnesium than in those treated with placebo (adrenaline: 1.05 +/- 0.16 vs 1.61 +/- 0.32 ng.mmol-1 creatinine; noradrenaline: 9.99 +/- 1.82 vs 18.48 +/- 2.41 ng.mmol-1 creatinine respectively in the first 12 h sample, P < 0.05).

CONCLUSIONS

Intravenous magnesium reduces ischaemic ECG changes, creatine kinase-MB release and urinary catecholamine excretion in the acute phase of unstable angina. Thus, magnesium may be a beneficial additional therapy for these patients. Further studies are required to confirm these finding.

Detection of myocardial damage by serial measurements of cardiac troponin T, CK MBmass, and TROPT rapid test

Detection of cardiac damage is greatly facilitated by serial blood measurements of myocardial cell markers. In many hospitals creatine kinase MBmass concentration (CK MBmass) constitutes the biochemical criterion (WHO) for acute myocardial infarction (AMI). Cardiac troponin T (TnT) is an even more sensitive and specific marker for myocardial damage. With discriminator levels of 10.0 and 0.10 micrograms/l, respectively, serial measurements of both markers provide a useful diagnostic strategy for ischemic heart disease. This survey reviews representative cumulated time curves in individual patients covering the spectrum of myocardial damage, including unstable angina pectoris (UAP), non-Q-wave and Q-wave infarctions with and without early reperfusion, re-infarction, and subacute infarction. Increased TnT detects minor myocardial damage (MMD) in over 30% of patients with UAP, although CK MBmass remains below its discriminator. Subacute infarction is detected by the wide diagnostic time window of the serum TnT at a time when CK MBmass has already returned to normal. In a substudy of 502 suspected cases of AMI, the distributions of maximum serum TnT concentrations within each patient series demonstrated that TnT had a diagnostic sensitivity of 100% and a specificity of 99%. Median, 5th and 95th percentiles of maximum TnT values within the diagnostic subgroups showed that serum TnT was increased five-fold more than CK MBmass. Median values of Q-wave AMI were higher than in non-Q-wave AMI. A diagnostic strategy using TROPT, a rapid test specific for the cardiac isoform of TnT with a detection limit 0.10 microgram/l, is presented.

Prognostic influence of elevated values of cardiac troponin I in patients with unstable angina

BACKGROUND

Elevations of the MB isoform of creatine kinase (CK) and cardiac troponin T seem to confer an adverse prognosis in unstable angina. We examined whether this prognostic influence is also present for cardiac troponin I (cTnI), a new and even more specific marker of myocardial injury.

METHODS AND RESULTS

We studied 106 patients with the clinical diagnosis of unstable angina showing chest discomfort at rest within 48 hours of admission, ECG evidence of myocardial ischemia, and normal values of total CK over the initial 16 hours of observation. The primary end point was death or nonfatal myocardial infarction (MI) at 30 days; the secondary end point was the incidence of cardiac events at 1 year. Blood was drawn every 8 hours for 3 days. Thirteen patients were excluded because of increased CK-MB mass concentrations within 16 hours of admission (non-Q-wave MI) and 2 because of inadequate blood sampling. Of the remaining 91 patients, 22 had cTnI elevations on admission (n=7) or after 8 hours (n=15). At 30 days, no deaths (0%) and 4 MIs (5.8%) occurred in the 69 patients with normal cTnI compared with 2 deaths (9.1%) and 4 MIs (18.2%) in the 22 patients with elevated cTnI. The combined incidence of death and nonfatal MI was 5.8% and 27.3%, respectively (P=.02). At 1 year, only 68% of patients with elevated cTnI were free of cardiac events, compared with 90% of those without elevations (P=.01).

CONCLUSIONS

These data indicate that cTnI is an important prognostic variable in patients with unstable angina. Elevations of cTnI predict an adverse short- and long-term prognosis.

Angiotensin-converting enzyme insertion/deletion polymorphism and restenosis after coronary angioplasty in unstable angina pectoris

We studied the relation between angiotensin-converting enzyme insertion/deletion gene polymorphism and restenosis in Caucasian patients who underwent coronary angioplasty for management of unstable angina pectoris. Our results indicate that, in contrast to previous reports in Japanese patients, no association exists between angiotensin-converting enzyme gene polymorphism and the development of restenosis in Caucasian patients with acute coronary syndromes.)

Intracellular neutrophil myeloperoxidase is reduced in unstable angina and acute myocardial infarction, but its reduction is not related to ischemia

OBJECTIVES

This study sought to assess neutrophil activation in acute coronary syndromes and its relation to ischemic episodes.

BACKGROUND

Neutrophil activation has been reported in unstable angina and acute myocardial infarction; however, it is not clear whether it is related exclusively to ischemia-reperfusion injury.

METHODS

We measured the index of intracellular myeloperoxidase in 1) patients with unstable angina, myocardial infarction, variant angina and chronic stable angina and in normal subjects (protocol A); and 2) in patients with unstable angina and acute myocardial infarction during the first 4 days of the hospital period (protocol B). To assess whether neutrophil activation was triggered by ischemia, the myeloperoxidase intracellular index was analyzed before and after spontaneous ischemic episodes and before and after ischemia induced by an exercise stress test in 10 patients with chronic stable angina. In 11 patients with unstable angina, we also compared values of the myeloperoxidase intracellular index at entry with those after waning of symptoms.

RESULTS

In protocol A, the myeloperoxidase intracellular index was significantly reduced in patients with unstable angina and acute myocardial infarction compared with patients with stable and variant angina and normal subjects (p < 0.01). In protocol B, the myeloperoxidase intracellular index did not change over time in patients with unstable angina and myocardial infarction. However, in 11 patients with waning symptoms, the myeloperoxidase intracellular index was significantly higher afer symptoms had waned (p < 0.05). In patients with unstable angina, 23 ischemic episodes were studied; no changes in the myeloperoxidase intracellular index were observed. In 10 patients with chronic stable angina and positive exercise stress test results, no significant differences in the myeloperoxidase intracellular index were observed after stress-induced ischemia.

CONCLUSIONS

Our study confirms that neutrophils are activated in acute coronary syndromes but suggests that their activation may not be only secondary to ischemia-reperfusion injury.

Identification of 92-kD gelatinase in human coronary atherosclerotic lesions. Association of active enzyme synthesis with unstable angina

BACKGROUND

Acute coronary ischemia is usually initiated by rupture of atherosclerotic plaque, leading to intracoronary thrombosis and clinical sequelae. The proximate cause of plaque rupture is unknown. Accordingly, we investigated the potential role of the 92-kD gelatinase member of the matrix metalloproteinase family in acute coronary ischemia.

METHODS AND RESULTS

Coronary atherectomy specimens from patients with atherosclerosis and an acute ischemic syndrome consistent with recent plaque rupture (unstable angina) (n = 12) were immunostained for the presence of 92-kD gelatinase; the results were compared with those obtained by identical study of atherectomy specimens from patients with atherosclerosis and angina but without acute ischemia (stable angina) (n = 12). Positive immunostaining for 92-kD gelatinase was present in 83% of specimens from both unstable and stable angina patients. However, intracellular localization of enzyme (indicating active synthesis) was documented in 10 of 10 positively stained specimens from patients with unstable angina compared with 3 of 10 positively stained specimens from patients with stable angina. Macrophages and smooth muscle cells were the major sources of 92-kD gelatinase in all specimens examined by immunostaining of adjacent sections.

CONCLUSIONS

92-kD gelatinase is commonly expressed in coronary arterial atherosclerotic lesions. Active synthesis of 92-kD gelatinase by macrophages and smooth muscle cells in atherosclerotic lesions may play a pathogenic role in the development of acute coronary ischemia.

Preoperative myocardial cell damage in patients with unstable angina undergoing coronary artery bypass graft surgery

BACKGROUND

Troponin-T is one of the contractile proteins of the myocardium. Its release into the circulation indicates various degrees of myocardial cell damage. Troponin-T may be measured in serum with a recently developed enzyme immunoassay. This immunoassay was used to evaluate the preoperative myocardial cell damage in patients with stable and unstable angina undergoing elective coronary artery bypass graft surgery, and it was compared with conventional assays of creatine kinase (CK) MB isoenzyme activity and mass.

METHODS

Twenty-one patients with unstable angina and 31 with stable angina were studied. Troponin-T, CK-MB activity, and CK-MB mass were measured 24 h before anesthesia and surgery, immediately before induction of anesthesia, before and after cardiopulmonary bypass, at the end of surgery, and 24 h afterward.

RESULTS

In 90% (19 of 21) of the patients with unstable angina, troponin-T was increased 24 h before anesthesia (median 0.33 microgram/l, range 0.15-5.2 micrograms/l), whereas only 3% (1 of 31) of the patients with stable angina had increased values (median 0.0 microgram/l, range 0.0-0.53 microgram/l). The difference was statistically significant (P < 0.001). The same profile was found in patients with and without unstable angina immediately before induction of anesthesia (86% [18 of 21] and 0%, respectively) and before cardiopulmonary bypass (62% [13 of 21] and 0%, respectively). In contrast to troponin-T, CK-MB activity was increased in only 0-14% of patients with unstable angina, and CK-MB mass was increased in only 9-24%. After bypass troponin-T increased in both groups (P < 0.01), but there was no longer a statistically significant difference between the groups. Twelve percent (4 of 31) of the patients in the stable angina group and 28% (6 of 21) in the unstable group had major cardiac events (P not significant).

CONCLUSIONS

The study data suggest that many patients with unstable angina undergoing elective coronary artery bypass graft surgery have already increased troponin-T levels preoperatively, although conventional biochemical markers such as CK-MB activity and mass are at a normal range. Increased troponin-T and normal CK-MB concentrations may reflect some degree of ischemic myocardial cell damage. Because of the small number of patients in the study, the influence of preoperative myocardial injury on perioperative outcome could not be clarified.

Detection of microinfarction in patients with unstable angina: study by 111In-antimyosin imaging

To examine the incidence of a positive indium-111 antimyosin scintigraphy in patients with unstable angina, we prospectively examined 25 patients with unstable angina and 11 patients with stable angina. All patients were injected with 2 mCi of indium-111 on admission and planar scintigraphy was performed 48 h later. Symptoms and signs of ischemia indicating severity of ischemia were monitored during the period between injection and scanning. None of the patients developed a rise in cardiac enzymes suggesting myocardial necrosis. Seven (28%) of the 25 patients with unstable angina had positive antimyosin scanning; no stable patients had positive scanning. All seven patients with unstable angina and positive scanning had signs of severe ischemia (four patients had multiple episodes of > 2/day, three patients had prolonged episodes of > 15 min, three patients had ST depression in > 3 EKG leads) while only one of the eighteen unstable patients with negative scannings had signs of severe ischemia (P < 0.001). In conclusion, (1) a significant number of unstable angina patients present positive antimyosin scanning without an elevation of cardiac enzymes and (2) these patients usually present multiple or severe episodes of ischemia indicating that during these episodes, minor myocardial necrosis, undetected by enzymes, may occur.

Early release of glycogen phosphorylase in patients with unstable angina and transient ST-T alterations

OBJECTIVE

To determine whether transient ST-T alterations in patients with unstable angina are associated with an increase in plasma glycogen phosphorylase BB concentrations on admission to hospital.

DESIGN

Prospective screening of patients with unstable angina for markers of myocardial cell damage.

SETTING

Accident and emergency department of university hospital.

PATIENTS

48 consecutive patients admitted for angina pectoris (18 with transient ST-T alterations). None of the patients had acute myocardial infarction according to standard criteria.

MAIN OUTCOME MEASURES

Creatine kinase and creatine kinase MB activities, creatine kinase MB mass concentration, and myoglobin, cardiac troponin T, and glycogen phosphorylase BB concentrations on admission.

RESULTS

All variables except for creatine kinase and creatine kinase MB activities were significantly higher on admission in patients with unstable angina and transient ST-T alterations than in patients without. However, glycogen phosphorylase BB concentration was the only marker that was significantly (p = 0.0001) increased above its discriminator value in most patients (16). In the 18 patients with transient ST-T alterations creatine kinase MB mass concentration and troponin T and myoglobin concentrations were significantly (p = 0.0001) less commonly increased on admission (in five, three, and two patients, respectively).

CONCLUSIONS

The early release of glycogen phosphorylase BB may help to identify high risk patients with unstable angina even on admission to an emergency department. Glycogen phosphorylase BB concentrations could help to guide decisions about patient management.

Angiotensin-1 converting enzyme (ACE) polymorphism in patients presenting with myocardial infarction or unstable angina

A deletion/insertion polymorphism in the ACE gene has been reported previously as a potent factor for myocardial infarction. We have tested the frequency of the deletion (D) allele of the ACE gene in 308 consecutive patients admitted to coronary care with chest pain. The gene frequencies were compared with those of 348 controls recruited from the London area. Of 108 Caucasian patients with myocardial infarction, the DD genotype was found more frequently than the combined DI and II genotypes (Chi-square, chi 2 = 5.07, 2P = 0.024). The overall D gene frequency was higher in myocardial infarction patients (125 of 216, 58%) than in controls (347 of 696, 49.9%) (chi 2 = 3.79, 2P = 0.052). In contrast, the DD genotype and D allele frequencies in patients with unstable angina were similar to those found in our normal population. A nonsignificant difference in allele frequency between myocardial infarction and unstable angina patients was observed but the small numbers of subjects studied precludes a more formal comparison. Since unstable angina and myocardial infarction represent a spectrum of coronary thrombosis, it is possible that the DD genotype favours the development of myocardial infarction, perhaps through the presence of higher serum ACE concentrations.