Hypercoagulable state in patients with schizophrenia: different effects of acute and chronic antipsychotic medications

Background

Previous studies reported higher incidences of venous thromboembolism and cardiovascular disease in schizophrenia patients and higher indicators of thrombosis, thrombocyte activation, and platelet dysfunction.

Objectives

To check if first-episode schizophrenia (FES) patients have a hypercoagulable state and determine whether acute and chronic antipsychotics have the same effect on blood coagulation or fibrinolysis-related biomarkers.

Design

Case-control study.

Methods

A total of 81 participants were grouped in FES, chronic schizophrenia (CS), and healthy controls (HCs). In addition to demographic data and clinical characteristics, immunological analyses were performed to measure plasma levels of D-dimer, plasminogen activator inhibitor-1 (PAI-1), soluble P selectin (sP-sel), tissue plasminogen activator (tPA), thrombotic precursor protein (TpP), and von Willebrand's disease factor (vWF).

Results

Compared to HC group, FES patients showed higher PAI-1 (28.61 ng/ml versus 15.69 ng/ml), sP-sel (2.78 ng/ml versus 1.18 ng/ml), and TpP (15.61 µg/ml versus 5.59 µg/ml) along with a higher PAI-1/tPA (3.12 versus 2.00). Acute antipsychotic medication reduced higher PAI-1 (28.61 → 21.99), sP-sel (2.78 → 1.87), tPA (9.59 → 5.83), TpP (15.61 → 10.54), and vWF (383.18 → 291.08) in FES patients. However, plasma sP-sel and vWF in CS patients returned to the pre-treatment levels in FES patients, and PAI-1/tPA significantly decreased compared to FES patients.

Conclusion

These results suggest a hypercoagulable state in FES patients and demonstrate contrast effects of acute and chronic antipsychotics on coagulation or fibrinolysis in schizophrenia patients.

Splanchnic Vein Thrombosis in Liver Cirrhosis After Splenectomy or Splenic Artery Embolization: A Systematic Review and Meta-Analysis

INTRODUCTION

Splenectomy and splenic artery embolization are major treatment options for hypersplenism and portal hypertension in liver cirrhosis, but may lead to splanchnic vein thrombosis (SVT), which is potentially lethal. We conducted a systematic review and meta-analysis to explore the incidence of SVT in liver cirrhosis after splenectomy or splenic artery embolization and the risk factors for SVT.

METHODS

All relevant studies were searched through the PubMed, EMBASE, and Cochrane Library databases. The incidence of SVT in liver cirrhosis after splenectomy or splenic artery embolization was pooled. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Sixty-six studies with 5632 patients with cirrhosis were included. The pooled incidence of SVT after splenectomy and splenic artery embolization was 24.6% (95% CI 20.2-29.3%) and 11.7% (95% CI 7.1-17.3%), respectively. A meta-analysis of three comparative studies demonstrated that the incidence of SVT after splenectomy was statistically similar to that after splenic artery embolization (OR 3.15, P = 0.290). Platelet count, mean platelet volume, preoperative splenic or portal vein diameter, preoperative or postoperative portal blood velocity, splenic volume and weight, and periesophagogastric devascularization were significant risk factors for SVT after splenectomy. Postoperative use of preventive antithrombotic therapy was a significant protective factor against SVT after splenectomy.

CONCLUSIONS

SVT is common in liver cirrhosis after splenectomy and splenic artery embolization. Coagulation and hemostasis factors, anatomical factors, and surgery-related factors have been widely identified for the assessment of high risk of SVT after splenectomy. Prophylactic strategy after splenectomy, such as antithrombotic therapy, might be considered in such high-risk patients.

STUDY REGISTRATION

This study was registered in PROSPERO with a registration number of CRD42019129673.

Biomarkers of coagulation and fibrinolysis in acute myocardial infarction: a joint position paper of the Association for Acute CardioVascular Care and the European Society of Cardiology Working Group on Thrombosis

The formation of a thrombus in an epicardial artery may result in an acute myocardial infarction (AMI). Despite major advances in acute treatment using network approaches to allocate patients to timely reperfusion and optimal antithrombotic treatment, patients remain at high risk for thrombotic complications. Ongoing activation of the coagulation system as well as thrombin-mediated platelet activation may both play a crucial role in this context. Whether measurement of circulating biomarkers of coagulation and fibrinolysis could be useful for risk stratification in secondary prevention is currently not fully understood. In addition, measurement of such biomarkers could be helpful to identify thrombus formation as the leading mechanism for AMI. The introduction of biomarkers of myocardial injury such as high-sensitivity cardiac troponins made rule-out of AMI even more precise. However, elevated markers of myocardial injury cannot provide proof of a type 1 AMI, let alone thrombus formation. The combined measurement of markers of myocardial injury with biomarkers reflecting ongoing thrombus formation might be helpful for the fast and correct diagnosis of an atherothrombotic type 1 AMI. This position paper gives an overview of the current knowledge and possible role of biomarkers of coagulation and fibrinolysis for the diagnosis of AMI, risk stratification, and individualized treatment strategies in patients with AMI.

P-Selectin Level at First and Third Day After Portal Hypertensive Splenectomy for Early Prediction of Portal Vein Thrombosis in Patients With Cirrhosis

We aimed to investigate the changes in p-selectin (p-sel), thrombus precursor protein, and D-dimer (D-D) in patients with cirrhosis after portal hypertensive splenectomy and explore its values on the prediction of postoperative portal vein thrombosis (PVT) formation. A total of 144 patients with cirrhosis with portal hypertension who underwent portal hypertensive splenectomy from January 2009 to December 2016 were enrolled in this study and divided into the thrombus and nonthrombus groups. The levels of p-sel, thrombus precursor protein (TpP), and D-D were measured by flow cytometry, enzyme-linked immunosorbent assay, and immunoturbidimetry, respectively. Sensitivity, specificity, and other values for p-sel, TpP, and D-D were calculated. The linear discriminant, logistic regression, and decision tree methods were used to analyze the p-sel value on the prediction of PVT formation. Seventy-nine patients were confirmed having postoperative PVT, with the incidence rate of 54.86%. No significant differences were observed in the p-sel, TpP, and D-D between the thrombus and nonthrombus groups before surgery, but these 3 indexes were obviously elevated in the thrombus group after operation (P < .01). P-selectin level on first day showed the highest positive predictive value (91.0%) and diagnostic coincidence rate (83.3%), while negative expected value (76.6%) was lower than those of TpP and D-D. Multiple analyses showed the prediction accuracy of PVT was 61.1% (P = .023), 97.2% (P < .001), and 97.2% (P < .001), respectively. P-selectin has a significant value in predicting PVT. P-selectin level on first and third day is valuable and feasible for the early prediction of PVT.

Impact of neutrophil apoptosis on haemostatic activation in chronic liver disease patients

Recent studies suggest the impact of apoptosis on the mechanisms leading to hypercoagulability. We aimed to clarify the potential role of neutrophil apoptosis in neutropenia and hypercoagulable state encountered in chronic liver disease patients. This study was conducted on 15 normal controls and 45 patients with chronic liver disease classified according to modified Child Pugh classification into, Child A, B and C groups (15 cases each). Haemostatic parameters studied include, prothrombin time, partial thromboplastin time, tissue factor, protein C antigen, protein S antigen, and markers of haemostatic activation [prothrombin fragment 1+2 (F1+2), thrombus precursor protein (TpP) and D-dimer]. Flowcytometric study was done for quantitative assay of neutrophil apoptotic subpopulations to detect the percentage of early and late apoptotic, and necrotic neutrophils using Annexin V-FITC/propidium iodide dye. Semiquantitative assay of apoptotic neutrophils showing DNA fragmentation was performed on neutrophil culture using terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labelling test. In addition to enzyme-linked immunosorbent assay for soluble Fas (APO-1/CD95) in culture supernatant. The results revealed a rise in the neutrophil apoptotic and necrotic markers with progression of the disease, and they were inversely correlated with the absolute neutrophil count. The apoptotic neutrophil cells showed a significant positive correlation with several haemostatic parameters (tissue factor, prothrombin fragment 1+2, thrombus precursor protein and D-dimer). Regression analysis proved that apoptotic parameters are independent determinants of prothrombotic markers, which further incriminate the apoptotic mechanisms in the hypercoagulable state encountered in this clinical setting.

Thrombus precursor protein and clinical outcomes in patients with acute coronary syndromes

OBJECTIVES

We sought to test the prognostic performance of thrombus precursor protein (TpP) in patients presenting with an acute coronary syndrome (ACS).

BACKGROUND

Because thrombus formation is a critical step in the development of ACS, a measurement of activated coagulation could yield important information. Thrombus precursor protein is a biomarker that is used to measure soluble fibrin polymers, which are the penultimate products in fibrin formation.

METHODS

We measured the levels of TpP in 284 healthy volunteers and in 2,349 patients with ACS.

RESULTS

Median TpP concentrations were 3.6 mug/ml (interquartile range 2.6 to 5.5) in the volunteers and 8.9 mug/ml (interquartile range 4.9 to 15.9) in the ACS patients (p < 0.001). Patients with ACS who had elevated TpP were older, more likely to be women, and more likely to have diabetes and pre-existing CAD (p < 0.02 for each). Thrombus precursor protein levels greater than the median were associated with a significantly increased risk for the composite of death, myocardial infarction (MI), or recurrent ischemia leading to rehospitalization or urgent revascularization through 10 months (hazard ratio [HR] 1.45, p < 0.001), as well as death or MI (HR 1.42, p = 0.02). We found that TpP correlated only weakly with cardiac troponin I, B-type natriuretic peptide, and high-sensitivity C-reactive protein (|r| <0.15 for each). After adjusting for clinical characteristics, cardiac troponin I, high-sensitivity C-reactive protein, and B-type natriuretic peptide, we found that patients with TpP levels greater than the median remained at significantly increased risk for the composite outcome (adjusted HR 1.51, p = 0.001) and death or MI (adjusted HR 1.58, p = 0.02).

CONCLUSIONS

In patients with ACS, increased levels of TpP are associated with an increased risk of death or ischemic complications. The incorporation of a marker of activated coagulation, such as TpP, with established cardiovascular risk factors may offer valuable complementary insight into risk assessment in ACS.

Thrombin generation in acute coronary syndrome and stable coronary artery disease: dependence on plasma factor composition

BACKGROUND

Acute coronary syndrome (ACS) is associated with thrombin formation, triggered by ruptured or eroded coronary atheroma. We investigated whether thrombin generation based on circulating coagulation protein levels, could distinguish between acute and stable coronary artery disease (CAD).

METHODS AND RESULTS

Plasma coagulation factor (F) compositions from 28 patients with ACS were obtained after onset of chest pain. Similar data were obtained from 25 age- and sex-matched patients with stable CAD. All individuals took aspirin. Patients on anticoagulant therapy were excluded. The groups were similar in demographic characteristics, comorbidities and concomitant treatment. Using each individual's coagulation protein composition, tissue factor (TF) initiated thrombin generation was assessed both computationally and empirically. TF pathway inhibitor (TFPI), antithrombin (AT), factor II (FII) and FVIII differed significantly (P < 0.01) between the groups, with levels of FII, FVIII and TFPI higher and AT lower in ACS patients. When thrombin generation profiles from individuals in each group were compared, simulated maximum thrombin levels (P < 0.01) and rates (P < 0.01) were 50% higher with ACS while the initiation phases of thrombin generation were shorter. Empirical reconstructions of the populations reproduced the thrombin generation profiles generated by the computational model. The differences between the thrombin generation profiles for each population were primarily dependent upon the collective contribution of AT, FII and FVIII.

CONCLUSION

Simulations of thrombin formation based on plasma composition can discriminate between acute and stable CAD.

Plasma markers of activated hemostasis in the early diagnosis of acute coronary syndromes

BACKGROUND

Because acute coronary syndromes (ACS) are caused by intracoronary thrombosis, plasma markers of coagulation have relevance for early diagnosis.

AIMS AND OBJECTIVES

To provide a critical review of these studies and specific attempts to close the diagnostic time gap left by traditional plasma markers of heart injury.

METHODS

Studies of ACS patients, with at least one control group, were included when blood samples were taken within 24 h after first symptoms prior to medication or intervention. Special attention was paid to studies reporting diagnostic performance, or combination of several markers into a single diagnostic index.

RESULTS

Markers with short plasma half-life (FPA, TAT, etc.) reflect ongoing thrombosis and may identify patients at increased risk. Markers with longer half-life (F1+2, D-Dimer, etc.) may be more useful to indicate a single acute thrombotic event. However, results are highly variable and depend on sampling time, clot property, degree of coronary obstruction and physiological condition. Early diagnostic performance of hemostatic markers was poor even when combined with heart injury markers.

CONCLUSIONS

Early measurement of hemostatic plasma markers in ACS patients provides pathophysiological information and may be helpful in risk stratification or to monitor anticoagulant therapy, but does not seem useful in routine clinical diagnosis of ACS.

Comparison of plasma D-dimer and thrombus precursor protein in patients with operable breast cancer as a potential predictor of lymph node metastasis

Fibrin formation and removal is continuous during the development of malignancy. Plasma D-dimer is indicative of ongoing fibrinolysis, and circulating soluble fibrin polymer [thrombus precursor protein (TpP)] represents thrombogenic activity. We evaluated the relationship between plasma D-dimer and TpP levels with tumor extent and examined the use of these markers as possible predictors of lymph node metastasis in breast cancer. Preoperative plasma levels of D-dimer and TpP were measured in these 120 patients (93 breast cancer, 27 benign breast disease) and 29 healthy controls. Plasma levels of D-dimer in patients with breast cancer were significantly higher than in healthy controls and in those with benign breast disease. Plasma D-dimer levels in patients with breast cancer were found to be significantly increased according to tumor stage. We also observed that plasma levels of D-dimer were higher in patients with lymph node metastasis than in patients without metastasis. In contrast, TpP levels were not significantly different by the tumor stages and lymph node metastasis. In conclusion, increased D-dimer levels in breast cancer may suggest that an ongoing fibrinolysis within breast cancer tissue occurs during tumor progression. Positive D-dimer levels might be useful for identifying metastatic lymph node in patients with operable breast cancer. However, plasma TpP was not found to be a sensitive marker for detecting tumor-associated subclinical coagulopathy.

Disseminated intravascular coagulation current concepts of etiology, pathophysiology, diagnosis, and treatment

The pathophysiologic mechanisms and clinical and laboratory manifestations of DIC are complex, partly because of inter-relationships within the hemostasis system. Only by clearly understanding these extraordinarily complex pathophysiologic inter-relationships can the clinician and laboratory scientist appreciate the divergent and wide spectrum of often-confusing clinical and laboratory findings in patients with DIC. Many therapeutic decisions to be made are controversial and lack validation. Nevertheless, newer antithrombotic agents and agents that can block, blunt, or modify cytokine activity and the activity of vasoactive substances seem to be of value. The complexity and variable degree of clinical expression suggest that therapy should be individualized depending on the nature of DIC, the patient's age, etiology of DIC, site and severity of hemorrhage or thrombosis, and hemodynamics and other appropriate clinical parameters.

Plasma levels of D-dimer and soluble fibrin polymer in patients with hepatocellular carcinoma: a possible predictor of tumor thrombosis

INTRODUCTION

Fibrin formation and removal occurs continuously during the development of malignancy. Moreover, plasma D-dimer is indicative of ongoing fibrinolysis, and soluble fibrin polymer (Thrombus precursor protein, TpP) represents thrombogenic activity. We evaluated the relationship between the levels of plasma D-dimer and TpP and tumor thrombosis in patients with hepatocellular carcinoma (HCC), and examined these markers as possible predictors of tumor thrombus in the portal or the hepatic vein.

MATERIALS AND METHODS

Plasma levels of D-dimer and TpP were measured in 66 HCC patients (38 without tumor thrombosis, 28 with tumor thrombosis) and 29 healthy controls, by enzyme immunoassay using an Asserachrom D-Di kit (Diagnostica Stago, France) and a TpP kit (American Biogenetic Sciences, USA).

RESULTS

The plasma levels of D-dimer and TpP in HCC patients were found to be significantly higher than those in healthy controls, and these values were also significantly higher in patients with tumor thrombosis than those without tumor thrombosis. Positive D-dimer (>367 ng/ml) correlated weakly with the presence of tumor thrombosis, whereas positive TpP (>5.4 microg/ml) correlated strongly with the presence of tumor thrombosis. By multivariant logistic analysis, positive TpP level was found to be a significant predictor of the presence of tumor thrombosis. In contrast, positive D-dimer level was not found to be a significant predictor for predicting tumor thrombosis.

CONCLUSIONS

Increased D-dimer and TpP levels in HCC may suggest that fibrinolysis and coagulation occur continuously during tumor progression. This study shows that a positive TpP level is a predictor of tumor thrombosis in HCC, which suggests that TpP may be useful for identifying tumor thrombus in the portal and hepatic veins.

Thrombus precursor protein, endogenous thrombin potential, von-Willebrand factor and activated factor VII in suspected deep vein thrombosis: is there a place for new parameters?

Because of its high negative predictive value, D-Dimer is an important parameter in the exclusion of deep vein thrombosis (DVT) but it produces a high number of false-positive results. We therefore evaluated different blood parameters in 74 consecutive patients with suspected DVT, whose final diagnosis was based on the results of Duplex ultrasound or venography. DVT was diagnosed in 52.7%. While D-Dimer, thrombin-antithrombin complexes, prothrombin fragment 1+2, von-Willebrand factor and thrombus precursor protein were significantly increased in patients with DVT, there was no influence concerning endogenous thrombin potential and activated factor VII. There was no significant correlation between the thrombus extension or the duration of symptoms with any of these parameters. D-Dimer showed the best sensitivity (94.9%) to specificity (45.7%) ratio and neither the sole nor the additional evaluation of any other investigated parameter increased its diagnostic performance. We, therefore, conclude that the determination of D-Dimer remains the 'gold standard' in the laboratory testing of patients with suspected DVT.

Evaluation of Coagulation Markers for Early Diagnosis of Acute Coronary Syndromes in the Emergency Room

Background: Diagnosis of acute coronary syndromes (ACS) is a major challenge for emergency physicians. Because soluble fibrin (sF) has been suggested as a potential early marker of impending myocardial ischemia, we were interested whether a sF bedside test could help in early identification of patients with ACS in the emergency department.

Methods: We evaluated plasma coagulation markers, including a newly developed sF bedside test, prothrombin fragment (F1+2), sF, and D-dimer, in a cross-sectional trial with 184 patients suggestive of ACS.

Results: Whereas 76% (13 of 17) of patients with unstable angina pectoris (UAP) had a positive sF bedside test, only 10 of 33 patients (30%) with non-ST-segment-elevation myocardial infarction and 10 of 44 patients (23%) with ST-elevation myocardial infarction tested positive. Three percent of controls (1 of 33) and 11% of patients (6 of 57) with preexisting stable angina had a positive sF bedside test (P &lt;0.001 for noncardiac chest pain vs ACS), yielding an overall specificity of 92% and a sensitivity of 35%. The sensitivity of the established coagulation markers was significantly less to detect ACS (11% for F1+2, 20% for thrombus precursor protein, and 18% for D-dimer; P &lt;0.02 vs sF bedside test). The sF bedside test presented the earliest objective indicator of impending myocardial damage in the majority (10 of 13) of ACS patients with a normal or nondiagnostic electrocardiogram (ECG).

Conclusions: A sF bedside test offers a specific tool for early identification of patients with ACS in an emergency department setting, although its sensitivity seems sufficient only for the early identification of patients with UAP. A sF bedside test could be useful, particularly in UAP patients with a nondiagnostic ECG.

Characteristics and prognostic impact of plasma fibrin monomer (soluble fibrin) in patients with coronary artery disease

We measured fibrin monomer (FM), soluble fibrin, as a marker of thrombin activity in plasma samples obtained in parallel with the first two routine samples for cardiac markers in 165 patients with acute chest pain admitted consecutively to our hospital. A reference limit of FM in a healthy population was set at 3.0 mg/l. Elevated plasma FM was observed in 48.8% of patients with acute coronary syndromes, in 42.3% of patients with specific non-coronary disease, in 31.5% of those with stable angina pectoris and in 18.2% of patients with non-specific chest pain. No significant difference was observed between sample 1 and sample 2 in patients not receiving thrombolytic treatment during the sampling period (P = 0.46). In patients with coronary artery disease, FM was significantly related to the level of cardiac troponin T (P = 0.001), but no correlation was observed between the individual plasma FM and cardiac troponin T values. Outcome analysis during the following 30 months after the index event in patients with acute coronary syndromes revealed higher FM levels in those with coronary re-events or death than in patients without new events (P = 0.001). This observation indicates a prognostic potential of FM in risk evaluation of patients with coronary artery disease.

Coagulation indicators in chronic stable effort angina and unstable angina: relationship with acute phase reactants and clinical outcome

The aim of the study was to evaluate which pattern of coagulation indicators characterizes unstable angina and, particularly, its relationship with short-term prognosis. Forty patients with unstable angina (UA Group) at admission in the intensive care unit, 40 patients with chronic stable effort angina (SEA Group), and 20 age- and sex-matched healthy controls were studied. Blood coagulation indicators were fibrinogen, prothrombin fragment F1 + 2 (F1 + 2), thrombus precursor protein (TpP), and D-dimer. C reactive protein (CRP) and cardiac Troponin I (cTnI) have also been determined and compared. Patients in the UA Group were followed for in-hospital adverse events (sudden death, acute myocardial infarction and angina refractory to medical therapy). CRP, D-dimer and cTnI plasma levels were significantly lower in the SEA Group than in the UA Group; the same trend was found for fibrinogen and F1 + 2 plasma levels, although not statistically significant. The TpP was similar in all groups. The control group showed the lowest levels for all indicators. Within the UA Group, 17 patients developed adverse events during hospitalization; F1 + 2, D-dimer, cTnI and CRP plasma levels were higher in these patients than in those with good outcome. Relative risks for adverse events associated with the highest tertile of D-dimer, cTnI, and CRP plasma levels were 8.4 (95% confidence interval, 1.5-48.9), 6.7 (95% confidence interval, 1.1-38.6) and 5.2 (95% confidence interval, 1.1-25.2), respectively. D-Dimer is significantly increased in patients with unstable angina and, in particular, in those who develop an adverse event.

Disseminated intravascular coagulation: a review of etiology, pathophysiology, diagnosis, and management: guidelines for care

The pathophysiologic mechanisms, clinical, and laboratory manifestations of DIC are complex in part due to interrelationships within the hemostasis system. Only by clearly understanding these extraordinarily complex pathophysiologic interrelationships can the clinician and laboratory scientist appreciate the divergent and wide spectrum of often confusing clinical and laboratory findings in patients with DIC. Many therapeutic decisions to be made are controversial and lack validation. Nevertheless, newer antithrombotic agents, and agents that can block, blunt, or modify cytokine activity and the activity of vasoactive substances appear to be of value. The complexity and variable degree of clinical expression suggests that therapy should be individualized depending on the nature of DIC, age, etiology of DIC, site and severity of hemorrhage or thrombosis and hemodynamics and other appropriate clinical parameters. At present, treatment of the triggering event, low-dose heparin or antithrombin concentrate and wise choice of components when indicated appear to be the most effective modes of therapy.

Endotoxin-induced activation of the coagulation cascade in humans: effect of acetylsalicylic acid and acetaminophen

During Gram-negative septic shock, lipopolysaccharide (LPS, endotoxin) induces tissue factor (TF) expression. TF expression is mediated by nuclear factor kappaB and amplified by activated platelets. TF forms a highly procoagulant complex with activated coagulation factor VII (FVIIa). Hence, we hypothesized that aspirin, which inhibits LPS-induced, nuclear factor kappaB-dependent TF expression in vitro and platelet activation in vivo, may suppress LPS-induced coagulation in humans. Therefore, we studied the effects of aspirin on systemic coagulation activation in the established and controlled setting of the human LPS model. Thirty healthy volunteers were challenged with LPS (4 ng/kg IV) after intake of either placebo or aspirin (1000 mg). Acetaminophen (1000 mg) was given to a third group to control for potential effects of antipyresis. Neither aspirin nor acetaminophen inhibited LPS-induced coagulation. However, LPS increased the percentage of circulating TF(+) monocytes by 2-fold. This increase was associated with a decrease in FVIIa levels, which reached a minimum of 50% 24 hours after LPS infusion. Furthermore, LPS-induced thrombin generation increased plasma levels of circulating polymerized, but not cross-linked, fibrin (ie, thrombus precursor protein), whereas levels of soluble fibrin were unaffected. In summary, a single 1000-mg dose of aspirin did not decrease LPS-induced coagulation. However, our study showed, for the first time, that LPS increases TF(+) monocytes, substantially decreases FVIIa levels, and enhances plasma levels of thrombus precursor protein, which may be a useful marker of fibrin formation in humans.

Cardiac markers: present and future

In the early twentieth century, acute myocardial infarction secondary to acute thrombotic coronary occlusion was considered a rare, fatal condition. Acute myocardial infarction is now one of the most-commmon serious illnesses in the industrialized world. Laboratory medicine now plays a crucial role in identifying risk factors, early events, and conditions triggering plaque rupture in coronary ischemic disease. However, the greatest progress in laboratory research has resulted from the discovery of new and more-promising biochemical markers of myocardial damage. The discovery of cardiac troponins, in particular, has heralded a new age in the diagnosis and treatment or management of a broad spectrum of diseases, grouped together under the heading of acute coronary syndrome, and including stable and unstable angina, and non-Q wave infarction to Q-wave infarction. Cardiac troponins, which are selectively released by damaged myocardiocytes, have a specificity that has not only allowed an improvement in the diagnosis of acute cardiac ischemic disorders, but has also enabled us to make a more-reliable stratification of risk and prediction of outcome. It is generally agreed that two biochemical markers should be used: an early marker (and we recommed myoglobin for this) and a definitive marker, which is cardiac troponin (I or T). Future research is likely to include the standardization of methods for measuring current markers, troponin I in particular, the assessment of rapid bedside tests, and the investigation of the relationship between cardiac markers and emerging immunological and coagulation parameters. Thrombogenesis is now recognized as important in the final process of coronary atherosclerosis, and new markers of thrombogenesis should be used to evaluate the risk of plaque rupture and to monitor the outcome of thrombolytic therapy. Moreover, recent vascular biology studies have provided information on the developmental stages of atherosclerosis and emphasized the importance of the endothelium as a modulator of vascular reactivity, atherogenesis, and plaque stability. The different types of laboratory test (biochemical, immunological, and coagulative) now available, should soon allow improvement in the diagnosis and therapy of ischemic coronary diseases.

National Academy of Clinical Biochemistry Standards of Laboratory Practice: Recommendations for the Use of Cardiac Markers in Coronary Artery Diseases

The Sixth Conference on the “Standards of Laboratory Practice Series”, sponsored by the National Academy of Clinical Biochemistry (NACB), was held on August 4–5, 1998, at the Annual Meeting of the American Association for Clinical Chemistry, in Chicago, IL. An expert committee was assembled to write recommendations on the use of cardiac markers in coronary artery diseases. The NACB Committee prepared a preliminary draft of the guidelines, made them available on the World Wide Web (www.nacb.org), and distributed them before the presentations. The recommendations were divided into four areas: the use of markers in the triage of patients with chest pain, acute coronary syndromes, clinical applications other than acute myocardial infarction and research, and assay platforms and markers of acute myocardial infarction. The recommendations were revised and subsequently re-presented in part at the “Biomarkers in Acute Cardiac Syndromes Conference”, sponsored by the Jewish Hospital Heart and Lung Institute, Louisville KY, on October 16–17, 1998. This report lists each recommendation, its scientific justification, and a summary of discussions from conference participants and reviewers.

Approximately 100 individuals responded to various versions of these recommendations via direct correspondences, telephone calls to Committee members, electronic mail correspondence to the Committee Chairman, or oral questions and comments raised during one of the two conference presentations. Some of the recommendations were changed to reflect the consensus opinion. In cases in which there was no consensus, the Committee included pertinent discussion without necessarily changing the original recommendations. At times, the Committee members felt that although a particular recommendation might not be the current standard of care today, they anticipate that it likely will be adopted in the near future.

Use of cardiac markers as assessed by outcomes analysis

OBJECTIVES

This article will describe the outcomes studies that have been performed or are needed in relation to biochemical markers in coronary artery diseases (CAD).

METHODS AND RESULTS

Studies in five major areas are reviewed: the need for emergency department (ED) chest pain centers and the role of cardiac markers; impact of cardiac marker testing frequency on length of stay (LOS); interpretation of cardiac troponins T and I for risk stratification of cardiac patients with unstable angina (UA); serum markers for determining the success of intravenous thrombolytic therapy following acute myocardial infarction (AMI), and its role in rescue percutaneous transluminal coronary angioplasty (PTCA); and need and criteria for implementation of new cardiac tests.

CONCLUSIONS

Chest pain centers reduce unnecessary admissions and costs for AMI rule outs. Laboratories must perform testing on a stat basis for rapid rule out of AMI. Stat testing will also result in a reduction in hospital LOS for patients who rule in for AMI. For UA patients, studies are needed to determine how results of cardiac markers can be used to improve cardiac outcomes. Serial measurements of myoglobin offer the earliest discrimination for successful reperfusion, and should be used if rescue PTCA becomes important therapeutically. New markers for early diagnosis are needed to complement tests such as myoglobin and CK-MB isoforms. Markers that assess early pathophysiologic events of AMI such as inflammation, thrombosis, and pre-necrosis ischemia have the most promise.