Usefulness of high-sensitivity C-reactive protein in predicting long-term risk of death or acute myocardial infarction in patients with unstable or stable angina pectoris or acute myocardial infarction

Inflammation is a crucial feature of atherosclerosis and a potential target to reduce cardiovascular events

Contrary to popular opinion, atherosclerosis is not a disease unique to modern civilization. In fact, atherosclerotic lesions have been found in the arteries of mummies dating back to 1,500 B.C., and yet our understanding of this complex process is still evolving. A fusion of basic science advances and clinical research findings has radically altered our traditional concepts about the pathogenesis and treatment of the clinical complications of atherosclerosis. Most physicians previously regarded the artery as a being merely a blood conduit that became encrusted with lipid detritus as part of the aging process. Modern-day treatment of atherosclerosis has arisen primarily from an understanding of the epidemiology of the disease rather than its pathophysiology, in that risk factors have traditionally been targeted. Our concepts of atherogenesis have evolved from vague ideas of inevitable degeneration to a much better defined scenario of molecular and cellular events. As we enhance our understanding of its fundamental mechanism, we can begin to approach atherogenesis as a modifiable rather than ineluctable process. Indeed, as we recognize now that inflammation plays a pivotal role in the process of atherosclerosis, it is noteworthy to evaluate the effect of modern therapies on this facet of the disease.

Serum high sensitivity C-reactive protein is associated with carotid intima-media thickness in type 2 diabetes

BACKGROUND

High sensitivity C-reactive protein (hsCRP) is more sensitive than standard C-reactive protein (CRP) assay in evaluating the risk of coronary heart disease and other atherosclerotic events. By this time, there are several reports that type 2 diabetic subjects have higher serum levels of hsCRP than those of non-diabetic subjects. However, there are few reports about factors which have influence upon the level of serum hsCRP in type 2 diabetic subjects. We had evaluated the association of serum hsCRP level with risk factors of cardiovascular diseases and carotid intima-media thickness (IMT) in type 2 diabetic subjects.

METHODS

One hundred and five patients (59 men and 46 women) with type 2 diabetes were recruited. Subjects with severe cardiovascular diseases were excluded. All subjects were undergone carotid ultrasonography for evaluation of carotid IMT. Serum hsCRP concentrations were measured.

RESULTS

Serum hsCRP level was correlated with mean left IMT (r = 0.366, P = 0.003), maximal left IMT (r = 0.370, P = 0.002), mean right IMT (r = 0.281, P = 0.023) and maximal right IMT (r = 0.370, P = 0.002), body mass index (r = 0.377, P < 0.001), waist circumference (r = 0.342, P < 0.001), waist-hip ratio (r = 0.229, P = 0.020), serum total cholesterol (r = 0.202, P = 0.024), serum triglyceride (r = 0.292, P = 0.022) and serum low-density lipoprotein (r = 0.133, P = 0.044).

CONCLUSION

Our result shows that serum hsCRP level is correlated with carotid IMT and the risk factors of cardiovascular diseases and may be useful to predict accelerated atherosclerotic process in type 2 diabetic subjects.

Relation of C-reactive protein to extent and complexity of coronary narrowing in patients with non-ST elevation acute coronary syndromes. A prospective cohort study

BACKGROUND

Inflammatory markers have been associated with adverse clinical outcome in patients with acute coronary syndromes (ACS). In addition, angiographic plaque morphology and extension of coronary artery disease has been related to worse prognosis in this group of patients. The aim of the present study was to determine if the clinical prognostic value of C-reactive protein (CRP), an inflammatory marker, can by associated with the angiographic findings in patients with non-ST elevation ACS.

METHODS

This prospective multicenter cohort study included 1253 patients with non-ST elevation ACS. CRP, which was considered positive (+) if >/=3 mg/l, was measured at a median of 9 h from symptoms onset and were kept blinded until the end of the study. Coronary angiography was performed in 633 patients (50%). The presence of complex coronary lesions (CCLs) was defined as the presence of any of the following: thrombus (+), Thrombolysis In Myocardial Infarction (TIMI) flow </=2, and/or ulcerated plaque (UP). The extension of coronary disease was defined as one, two or three vessel disease.

RESULTS

CRP was found to be (+) in 354 patients (60%). CCLs were present in 266 patients (46%), 166 (47%) in CRP (+) and 100 (42%) in CRP negative (-) patients, P=0.31. There was also no association between the extension of coronary disease and the CRP levels.

CONCLUSIONS

In this large consecutive cohort of non-ST elevation ACS patients, CRP, an inflammatory marker, does not predict either the extension or the complexity of coronary disease. Even though CRP is a strong predictor of worse clinical outcome in patients with ACS, this could not be explained by the angiographic anatomic findings.

Frequency of elevation of C-reactive protein in atrial fibrillation

Inflammation has been implicated in the pathogenesis of cardiovascular diseases. C-reactive protein (CRP), a marker of systemic inflammation, predicts the risk of coronary events and stroke. Atrial fibrillation (AF) is associated with atrial structural changes that may have an inflammatory basis. We tested the hypothesis that CRP is a risk factor for AF. Subjects were those included in the database registry of the Intermountain Heart Collaborative Study from 1994 to 2001. Patients who had >or=1 electrocardiogram that demonstrated AF formed the disease group (n = 347), and those who had neither electrocardiographic nor clinical evidence for AF comprised the control group (n = 2,449). Logistic regression assessed the quartile (Q) of CRP and 13 other clinical and angiographic predictors of AF. Average age was 63 +/- 12 years, 33% were women, and 61% had advanced coronary artery disease. Patients who had AF were older (by 7 years) and more frequently had a history of heart failure than did controls (41% vs 9%). CRP was higher in patients who had AF than in controls (p <0.001). Q-CRP was a univariable predictor of AF (odds ratio 1.39/Q, 95% confidence interval 1.25 to 1.55, p <0.001). Adjusting for age and heart failure decreased the predictive value of Q-CRP to 1.20/Q (95% confidence 1.07 to 1.34, p = 0.002), whereas further adjustment for 11 other variables had little additional effect (odds ratio 1.19/Q, 95% confidence interval 1.06 to 1.33, p = 0.003). Thus, high levels of CRP independently predicted an increased risk of AF among a large, prospectively studied patient cohort that was assessed angiographically. Increased CRP is a new risk marker for AF propensity, and testing therapies that target inflammation should be considered.

White Blood Cell Count and C-reactive Protein Predict Short-term Prognosis in Acute Myocardial Infarction

An elevated white blood cell (WBC) count and C-reactive protein (CRP) concentration are associated with acute myocardial infarction (AMI) and long-term mortality in patients with coronary artery disease. Their relationship with short-term prognosis following AMI is less clear, however. We investigated the relationship between WBC count and CRP concentration, obtained at the time of admission, and the development of subsequent ischaemic coronary events (SICE) within 30 days of AMI in 177 patients. After adjustment for confounding factors, CRP concentration was found to be a strong independent predictor for SICE within 30 days in patients with AMI. WBC count was not found to be an independent predictor, but there was a strong correlation between high WBC counts and the onset of SICE within 30 days in patients with AMI. We conclude that CRP concentration and WBC count could be used to predict the short-term prognosis of patients with AMI.

Inflammation and atherosclerosis

Inflammation plays a pivotal role in all stages of atherogenesis, from foam cell to plaque formation to rupture and ultimately to thrombosis. Insight gained from recent basic and clinical data linking inflammation to atherosclerosis has yielded important diagnostic and prognostic information. Low-grade chronic inflammation as measured by high sensitivity C-reactive protein predicts future risk of acute coronary syndrome independent of traditional cardiovascular risk factors. In addition, individuals with higher "inflammatory burden" gain the largest absolute risk reduction with aggressive risk-lowering therapy. The link between inflammation and atherosclerosis provides a new venue for future pharmacologic agents that may slow the progression of atherosclerosis by inhibiting inflammation.

Adrenomedullin as a sensitive marker for coronary and peripheral arterial complications in patients with atherosclerotic risks

Plasma adrenomedullin (AM) levels are elevated in various pathological states including cardiovascular and inflammatory diseases. The present study investigated whether an increased AM level is a marker of vascular complications in patients with atherosclerotic risks. In 114 patients with cardiovascular risks and/or diseases including ischemic heart disease (IHD) and peripheral arterial disease (PAD), plasma AM concentration and other inflammatory markers such as high sensitive C-reactive protein (CRP) and interleukin (IL)-6 were examined. The plasma AM level was not altered by the absence or presence of each of four major risk factors, i.e., hypertension, diabetes mellitus, hyperlipidemia, and smoking and its level was not significantly correlated with blood pressure, plasma glucose, or serum lipid levels. The patients with IHD had a significantly higher concentration of plasma AM than those without IHD. The AM level in subjects with PAD was also increased significantly compared with those without PAD. The plasma AM was strongly correlated with inflammatory parameters such as CRP and IL-6. Among AM, CRP, and IL-6, however, only AM was an independent predictor for both IHD and PAD by multiple logistic regression analysis. Our findings suggest the possibility that plasma AM is a novel sensitive marker for the presence of vascular lesions in patients with atherosclerotic risks.

Elevated white cell count in acute coronary syndromes: relationship to variants in inflammatory and thrombotic genes

BACKGROUND

Elevated white blood cell counts (WBC) in acute coronary syndromes (ACS) increase the risk of recurrent events, but it is not known if this is exacerbated by pro-inflammatory factors. We sought to identify whether pro-inflammatory genetic variants contributed to alterations in WBC and C-reactive protein (CRP) in an ACS population.

METHODS

WBC and genotype of interleukin 6 (IL-6 G-174C) and of interleukin-1 receptor antagonist (IL1RN intronic repeat polymorphism) were investigated in 732 Caucasian patients with ACS in the OPUS-TIMI-16 trial. Samples for measurement of WBC and inflammatory factors were taken at baseline, i.e. Within 72 hours of an acute myocardial infarction or an unstable angina event.

RESULTS

An increased white blood cell count (WBC) was associated with an increased C-reactive protein (r = 0.23, p < 0.001) and there was also a positive correlation between levels of beta-fibrinogen and C-reactive protein (r = 0.42, p < 0.0001). IL1RN and IL6 genotypes had no significant impact upon WBC. The difference in median WBC between the two homozygote IL6 genotypes was 0.21/mm3 (95% CI = -0.41, 0.77), and -0.03/mm3 (95% CI = -0.55, 0.86) for IL1RN. Moreover, the composite endpoint was not significantly affected by an interaction between WBC and the IL1 (p = 0.61) or IL6 (p = 0.48) genotype.

CONCLUSIONS

Cytokine pro-inflammatory genetic variants do not influence the increased inflammatory profile of ACS patients.

Pregnancy-Associated Plasma Protein A and Its Endogenous Inhibitor, the Proform of Eosinophil Major Basic Protein (proMBP), Are Related to Complex Stenosis Morphology in Patients With Stable Angina Pectoris

Background— The metalloproteinase pregnancy-associated plasma protein-A (PAPP-A) has been implicated in coronary plaque disruption. Its endogenous inhibitor, the proform of eosinophil major basic protein (proMBP), may also play a role in this process. Atheromatous plaque disruption often presents as complex angiographic lesions. We sought to assess whether PAPP-A, proMBP, and PAPP-A/ProMBP ratio are markers of angiographic plaque complexity in patients with chronic stable angina.

Methods and Results— We studied 396 stable angina patients (age 63±10 years, 230 men) of whom 289 had angiographically documented coronary artery disease (≥75% stenosis). All coronary stenoses ≥30% diameter reduction (n =531 in 322 patients) were assessed and classified as complex (n =228) or smooth (n =303) by previously validated criteria. PAPP-A, proMBP, and C-reactive protein (hs-CRP) serum levels were measured by ELISA. Patients with complex coronary stenoses had a significantly ( P <0.001) higher PAPP-A/proMBP ratio (3.1±1.2 versus 2.7±0.8×10 −3 ) and PAPP-A levels (5.9±1.6 versus 5.1±1.4 mIU/L) than those without. On univariate analysis, male gender ( P <0.001), age ( P <0.001), previous history of myocardial infarction ( P =0.013), reduced ejection fraction ( P <0.001), severe coronary artery disease ( P <0.001), aspirin treatment ( P <0.001), PAPP-A levels ( P <0.001), and PAPP-A/proMBP ratio ( P <0.001) were correlated with the number of complex stenoses. Multiple regression analysis showed that male gender, age, severe coronary artery disease, and PAPP-A/proMBP ratio were independent predictors of the number of angiographically complex stenoses.

Conclusions— In patients with stable angina, PAPP-A and PAPP-A/proMBP ratio are associated with angiographic plaque complexity.

Chronic infection and coronary artery disease

On a variety of fronts, chronic infection has been found to be significantly associated with the development of atherosclerosis and the clinical complications of unstable angina, myocardial infarction, and stroke. For the most part, these relationships are still just associations. Failure to confirm initial reports of serologic associations also has been common. Specific causative relationships on par with that determined between H pylori and peptic ulcer disease have not yet been established. Potential mechanisms whereby chronic infections may play a role in atherogenesis are myriad. In the case of C pneumoniae, the effect may result from direct vessel wall colonization that may damage the vessel either directly or indirectly by initiating immunologic responses. In other cases the effect may simply be that of enhancing the pre-existing chronic inflammatory response of the body to standard risk factors such as hyperlipidemia. Even though the infectious agent may not directly infect the vessel wall, it may perform its critical role from afar. Chronic infection might also influence pre-existing plaque by enhancing T-cell activation or other inflammatory responses that may participate in the destabilization of the intimal cap. Hence chronic infection may play a role either in the initiation, progression, or the destabilization of atherosclerotic plaques. The infectious agents with the most evidence to support an etiologic role in atherosclerosis include C pneumoniae and cytomegalovirus. Evidence is mounting for a variety of other potential agents including other herpes viruses, influenza, other specific bacteria (such as M pneumoniae), and chronic infections with common bacterial agents (periodontal disease, chronic bronchitis, and chronic urinary tract infection, among others) [191]. Future studies are expected to elucidate further the pathophysiologic relationship between chronic infection and atherosclerosis and to evaluate further the potential of a variety of treatment approaches, including antibiotics.

Raised concentrations of macrophage colony stimulating factor in severe unstable angina beyond the acute phase are strongly predictive of long term outcome

OBJECTIVE

To evaluate the long term prognostic value of macrophage colony stimulating factor (MCSF), interleukin-6 (IL-6), and tumour necrosis factor alpha (TNFalpha) measured in serum six weeks after the occurrence of unstable angina.

SUBJECTS

119 consecutive patients, mean (SD) age 58 (10) years, with severe unstable angina (Braunwald class IIIb); controls were 96 subjects of similar age and sex distribution.

DESIGN

MCSF, IL-6, and TNFalpha were measured on admission, at discharge, and six weeks later, and the patients were followed for two years. Clinical end points were: cardiac death, readmission for acute coronary syndromes, and revascularisation.

SETTING

District general hospital.

RESULTS

113 patients completed follow up, during which two died of non-cardiac causes. Of the remaining 111 patients, 39 (35.1%) had a cardiac event (two deaths, 15 revascularisations, and 22 readmissions for acute coronary syndromes). MCSF and IL-6 concentrations at six weeks were higher in patients with cardiac events than in those without (424 v 306 pg/ml, p = 0.0008, and 6.6 v 4.5 pg/ml, p = 0.01, respectively). Cytokine concentrations at six weeks were also significantly higher than in the control group. Logistic regression analysis showed that MCSF concentrations were the only independent predictors of future events, with an adjusted odds ratio for events of 4.1 (95% confidence interval 1.1 to 14.8; p = 0.03). The two year survival free of cardiac events was significantly lower in patients with MCSF concentrations in the highest tertile (values > or = 468 pg/ml) than in those with values < 468 pg/ml.

CONCLUSIONS

Increased MCSF concentrations beyond the acute phase are strongly predictive of long term outcome in patients with severe unstable angina.

Integrating antithrombin and antiplatelet therapies with early invasive management for non-ST-segment elevation acute coronary syndromes

Non-ST-segment elevation acute coronary syndromes are a dramatic manifestation of coronary artery disease. Multiple clinical trials have shown that early cardiac catheterization improves clinical outcomes in patients with non-ST-segment elevation acute coronary syndromes. Many antithrombotic agents effectively manage unstable coronary syndromes and serve as adjuncts to percutaneous coronary intervention. Yet, the growing number of pharmacologic agents makes early management of non-ST-segment elevation acute coronary syndromes increasingly complex. We review the current evidence regarding the optimal integration of early antithrombotic and antiplatelet therapies with early coronary angiography and subsequent revascularization.

Admission C-reactive protein levels and 30-day mortality in patients with acute myocardial infarction

BACKGROUND

Elevated C-reactive protein levels are associated with an increased risk of subsequent cardiovascular events in patients with unstable angina. However, limited information is available concerning the value of C-reactive protein levels in patients with acute myocardial infarction.

METHODS

We prospectively studied 448 consecutive patients (mean [+/- SD] age, 60 +/- 12 years) with acute myocardial infarction. Serum C-reactive protein levels were measured within 12 to 24 hours of symptom onset, and divided into tertiles. Infarct size was determined by echocardiographic examination that was performed on day 2 or 3. Patients were followed for 30 days for mortality and subsequent cardiac events.

RESULTS

At 30 days, 4 deaths (3%) occurred in patients in the lowest C-reactive protein tertile, 15 (10%) in patients in the middle tertile (P = 0.02 vs. the lowest tertile), and 33 (22%) in patients in the highest tertile (P <0.001 vs. the lowest tertile). In a multivariate analysis, C-reactive protein in the upper tertile was associated with 30-day mortality (relative risk = 3.0; 95% confidence interval [CI]: 1.3 to 7.2; P = 0.01) and the development of heart failure (odds ratio = 2.6; 95% CI: 1.5 to 4.6; P = 0.0006). C-reactive protein levels were not associated with the development of postinfarction angina, recurrent myocardial infarction, or the need for revascularization.

CONCLUSION

Plasma C-reactive protein level obtained within 12 to 24 hours of symptom onset is an independent marker of 30-day mortality and the development of heart failure in patients with acute myocardial infarction. These findings suggest that C-reactive protein levels may be related to inflammatory processes associated with infarct expansion and postinfarction ventricular remodeling.

C-reactive protein: a novel marker of cardiovascular risk

Patients without traditional cardiovascular risk factors continue to suffer from cardiovascular events, which has prompted a search for novel markers to better assess cardiovascular risk. Inflammatory biomarkers have surfaced as prime candidates, given the integral role of inflammation in atherosclerosis. C-reactive protein (CRP) measurements in particular have emerged as powerful predictors of cardiovascular risk in a broad spectrum of patient populations. Newer high sensitivity CRP assays now in use are standardized and reproducible, and can detect variations in CRP below the limit of standard assays. In primary prevention populations, studies have shown up to a 2-4-fold increased risk of cardiovascular events in healthy patients with elevated CRP levels. In this population, models incorporating CRP and lipid parameters appear to predict risk significantly better than lipids alone. In patients with established cardiovascular disease and in patients undergoing percutaneous coronary interventions, CRP levels may help predict short- and long-term prognosis, identifying subgroups of patients at increased risk of recurrent events. CRP levels may also prove useful in targeting therapy for primary and secondary prevention, by identifying patients who would most benefit from medications such as statins and aspirin. This review presents an overview of the data regarding CRP measurement for cardiovascular risk assessment.

The role of C-reactive protein on the long-term clinical outcome after primary or rescue percutaneous coronary intervention

BACKGROUND

We examined the clinical and angiographic outcomes, success rate of the percutaneous coronary intervention (PCI) and long-term survival rate after primary or rescue PCI in patients with acute myocardial infarction (AMI) according to the level of the C-Reactive Protein (CRP) on admission.

METHODS

Two hundred and eight consecutive patients with AMI who underwent primary or rescue PCI between 1997 and 1999 at Chonnam National University Hospital were divided into two groups: Group I (n = 86, 59.9 +/- 9.3 years, male 74.4%) with a normal CRP (< 1.0 mg/dL, mean value = 0.43 +/- 0.14 mg/dL) on admission and Group II (n = 122, 59.1 +/- 10.4 years, male 83.6%) with an elevated CRP (> or = 1.0 mg/dL, mean value = 3.50 +/- 0.93 mg/dL) on admission.

RESULTS

There were no significant differences in teh baseline characteristics noted between the two groups. The incidence of cardiogenic shock was higher in Group II than in Group I (Group I; 3/86, 3.5% vs. Group II; 15/122, 12.3%, p = 0.026). The coronary angiographic findings did not differ between the two groups. The ejection fraction and Thrombolysis In Myocardial Infarction flow grade improved after PCI in both groups. The primary success rate of PCI was 94.2% (81/86) in Group I and 95.1% (116/122) in Group II (p = 0.776). The survival rates for Group I were 97.7%, 97.7% and 96.5%, and those for Group II were 91.8%, 91.0% and 86.9% at 1, 6 and 12 months, respectively (p = 0.043 at 1 month, p = 0.040 at 6 months, p = 0.018 at 12 months).

CONCLUSION

A high incidence of cardiogenic shock and worse long-term survival after PCI are observed in AMI patients with an elevated CRP.

Role of inflammation in cardiovascular disease: how to use C-reactive protein in clinical practice

Acute coronary syndromes, stroke, and sudden death are common complications of a disrupted atherosclerotic plaque. Unstable plaque is a result of multiple factors but is commonly characterized by an infiltrate of inflammatory cells. Medical research strongly supports a role for inflammation in the pathogenesis, progression, and disruption of atherosclerotic plaque. Medical science also has improved our understanding of the complex interactions between our environment and our immune, coagulation, and cardiovascular systems. Clinical studies have demonstrated systemic markers of inflammation to be strong predictors of clinical events, and specific treatments of atherosclerosis and its risk factors have been associated with reductions in inflammatory markers. The authors review the current understanding of the role of inflammation in the pathogenesis of atherosclerosis, the common inflammatory markers, and potential anti-inflammatory therapy. Among several potential circulating markers of vascular inflammation, high sensitivity C-reactive protein is best validated and standardized as a marker for cardiovascular risk assessment. Nevertheless, there remain many uncertainties in utilizing C-reactive protein in clinical practice. Here, the authors describe the central role of C-reactive protein in atherosclerosis, review the studies demonstrating predictive value of C-reactive protein, describe the factors requiring consideration when utilizing C-reactive protein, discuss clinical scenarios in which measurement of C-reactive protein may be helpful, and suggest ways to interpret and treat elevated C-reactive protein levels. Finally, the authors summarize future expectations for assessing and modulating the vascular inflammation to inhibit initiation and progression of the atherosclerotic process.

Thermography of the cardiovascular system

The identification of vulnerable plaque is one of the primary goals in cardiology during the last years. Several techniques have been developed for the anatomic and functional assessment of atherosclerotic plaques. Thermography is a new method for the evaluation of the inflammatory process locally within the atherosclerotic plaque. Several animal and clinical studies demonstrated the value of thermography not only for the detection of inflamed atherosclerotic plaques, but its use in new fields like in the evaluation of inflammation in the coronary vascular bed and the cardiovascular system. This article reviews the developments and the clinical implications of thermography.

Economics and quality of care for patients with acute coronary syndromes: the impending crisis

Several factors are placing significant financial burdens on the health care system today. These include the growing older population, the obesity and type II diabetes epidemics, and the attendant increased prevalence of heart disease, which remains the leading cause of death in the United States. In response, cardiovascular medicine is undergoing sweeping change in the use of advanced technology and interventions. In addition, biomarkers, such as troponin, are emerging as critical predictors of responses to therapy, particularly for coronary stenting. Future trends in the treatment of acute coronary syndromes (ACS) will embrace the use of genomic solutions, such as gene expression profiling, to predict therapeutic outcomes. Careful consideration will need to be given to these innovative approaches to ensure they are cost effective.