Slide 2. Beyond cholesterol: predicting cardiovascular risk in the 21st century As we understand more about the biology of atherothrombosis, we need to move beyond standard cholesterol screening if we are to appreciate the promise of preventive early intervention therapies. While hyperlipidemia, hypertension, and diabetes, as well as the behavioral risk factors of smoking and diet, remain major critical modifiable risk factors for vascular disease, we have learned over the years that many hemostatic and thrombotic markers such as lipoprotein(a), D-dimer, and homocysteine, inflammatory markers such as C-reactive protein (CRP), fibrinogen, and interleukin-6, and genetic markers are all part of the evolving understanding of cardiovascular risk. Keywords: markers, risk factors Slide type: figure (chart)
Slide 4. Inflammation and atherosclerosis Why study inflammation in heart disease? Two general hypotheses emerging from the basic science community have driven this research. The first is the concept that inflammation itself may determine plaque stability. Unstable plaques have increased leukocytic infiltrates in them, and T-cells and macrophages predominate at the rupture sites in these plaques. Also, cytokines and metalloproteinases may influence plaque stability and the degradation of the fibrous cap. But in addition to the idea that atherosclerosis is fundamentally an inflammatory disorder is the recognition in the basic science literature that lipid lowering in general may reduce plaque inflammation. That is to say, experimental studies have now demonstrated reduced macrophage number within atherosclerotic plaques treated with lipid-lowering statin therapy as well as decreased expression of collagenolytic enzymes and the attenuation of other markers of the inflammatory process. References: Libby P. Molecular bases of the acute coronary syndromes. Circulation 1995;91:2844-2850. http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7758192&dopt=Abstract Ross R. Atherosclerosis—an inflammatory disease. N Engl J Med 1999;340:115-126. http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9887164&dopt=Abstract Keywords: inflammation, plaque stability Slide type: text
Slide 5. Is there clinical evidence that inflammatory markers predict future coronary events and provide additional predictive information? In this discussion, we are going to focus on the clinical question of whether there is clinical evidence that inflammatory markers can be used to predict future coronary events, and if so, whether they provide additional predictive information to that obtained from traditional risk factors. Keywords: inflammation, inflammatory markers Slide type: text
Slide 24. Evaluating novel risk factors for CAD Any novel risk factor must meet a number of criteria before achieving clinical utility. These include consistency of prospective data, strength and magnitude of association, and the independence of that association in epidemiologic studies. Further, there must be a standardized measure with low variability and high reproducibility, and it helps if a biologically plausible hypothesis can link the marker of interest to the outcome. Finally, the screening techniques should be low cost and preferentially modifiable. Many of these issues are being evaluated for the hs-CRP test. Keyword: risk factors Slide type: text
Slide 29. Biomarkers for venous and arterial thrombosis As we accumulate more data on biomarkers to identify individuals at risk for venous and arterial thrombosis, it has become apparent that some markers such as homocysteine and D-dimer may identify individuals at risk for both venous and arterial thrombosis, whereas the majority of markers identify individuals at risk for either arterial thrombosis (e.g., hs-CRP) or venous thrombosis (factor V Leiden). Keywords: markers, risk factors Slide type: table
Slide 30. Biomarkers for venous and arterial thrombosis (cont'd) As we accumulate more data on biomarkers to identify individuals at risk for venous and arterial thrombosis, it has become apparent that some markers such as homocysteine and D-dimer may identify individuals at risk for both venous and arterial thrombosis, whereas the majority of markers identify individuals at risk for either arterial thrombosis (e.g., hs-CRP) or venous thrombosis (factor V Leiden). Keywords: markers, risk factors Slide type: table
Over the last decade, research in many laboratories has begun to unravel the association of the inflammatory cascade to the atherosclerotic process. Studies have examined various aspects of the immune system, including adhesion molecules (ICAM-1 and VCAM-1, E-selectin and P-selectin), cytokines (interleukin-6, tumor necrosis factor-alpha) and other acute phase reactants such as fibrinogen and serum amyloid A. Of these inflammatory bio-markers, C-reactive protein (CRP) has emerged as the best clinical tool for cardiovascular risk detection.
This slide depicts the molecular helices which together form the C-reactive protein (CRP) pentamer. This structure is highly stable, provides for a long half-life, and results in an easily measured biomarker of inflammation. CRP is a key component of the innate immune response and participates in a number of processes related to the development of atherosclerosis including a role in the oxidation of LDL. The role of CRP as a marker for underlying inflammation and its contribution to cardiovascular risk lie at the heart of the rationale for the JUPITER trial.
Slide 25. CRP vs hs-CRP The standard CRP test is inadequate for detecting the low grade levels of inflammation measured with the hs-CRP test. CRP is an acute phase protein produced in the liver in response to cytokine production. The levels will increase several hundredfold if not a thousandfold during acute infection and tissue injury. High sensitivity assays are needed to detect the CRP levels within the normal range that have been used to predict vascular risk. Keyword: C-reactive protein, measurement Slide type: text
Slide 23. Potential mechanisms linking CRP to atherothrombosis All these data raise intriguing biological issues concerning mechanisms linking inflammation in general and CRP in particular to atherothrombosis. As indicated earlier, it is no longer thought that this association is simply due to confounding by cigarette consumption, nor is it believed that this is simply due to an acute phase response or an innocent bystander effect, because many studies demonstrate predictive value 5, 10, and even 15 years in advance of the first vascular event. On the other hand, cytokine function is a very important part of this process. Several studies by investigators around the world have now demonstrated that cytokine mediators such as IL-6, TNF- , and IL-1 also are elevated among individuals at risk, and these are important since these are the primary hepatic drivers of CRP production. In addition, there are many direct effects of CRP on the vascular system. CRP is a pentraxin and is part of the native immune response. It is involved in complement activation, and very intriguing data have been presented suggesting that CRP itself may increase the expression of several cell adhesion molecules that are associated with the attachment and transmigration of white cells at the vascular endothelium. It has also been suggested that infection by Chlamydia, Helicobacter pylori, or cytomegalovirus may be associated with chronic inflammation. On the right side of this slide is a look towards the future. Many of us think that the inflammatory markers may have a role in the detection of subclinical atherosclerosis, and it is now clear that insulin resistance and obesity are involved in this process as well. Because of the interrelation of endothelial dysfunction and the dysmetabolic syndrome with the inflammatory processes, CRP response in general may provide us with a marker for plaque vulnerability. Keywords: atherothrombosis, C-reactive protein, cytokines, infection, inflammation Slide type: text
It may be useful to provide an historical perspective on what led to the consideration of CRP as a clinically powerful marker of cardiovascular risk. This slide shows data from the Physicians’ Health Study (PHS), an epidemiologic study in 22,071 healthy middle-aged men. As will be done in the JUPITER trial, all participants in the PHS supplied baseline plasma and DNA samples. As shown here, in the PHS population, increasing levels of CRP at study entry were associated with a dramatic increase in risk of future myocardial infarction. Thus, these data established that CRP had the ability to predict vascular events over the next 8 to 10 years of a healthy individual’s life.
Similar to data for first-ever myocardial infarction, increasing levels of CRP in the PHS were also associated with a dramatic increase in risk for future thromboembolic stroke. This finding is of particular importance as LDL cholesterol levels are not a strong predictor of stroke, yet statin therapy has been proven to reduce stroke risk. Thus, part of the hypothesis to be studied in the JUPITER trial regarding CRP, statin therapy, and prevention derive from this early work.
In fact, as shown here, CRP has now been evaluated as a novel risk factor for future myocardial infarction, stroke, peripheral arterial disease, and sudden cardiovascular death in over a dozen major epidemiologic studies. The association between CRP and cardiovascular risk has been consistently observed over a wide array of patient populations.
A critical clinical question has been whether or not CRP levels add to information based upon cholesterol evaluation. As shown here, high sensitivity evaluation for CRP (hs-CRP) clearly adds to the predictive value of the total to HDL cholesterol ratio. As also shown, risk is high for those with elevated levels of CRP but average cholesterol values. Such patients, however, are largely missed by current screening protocols.
When directly compared with many other novel risk factors including homocysteine, lipoprotein(a), and standard lipid measures, hs-CRP has proven to be the single strongest predictor of risk, as is shown here in further data from the Women’s Health Study. It is important to note that CRP levels do not correlate well with cholesterol levels. Thus, as also shown in this slide, the addition of CRP evaluation to cholesterol screening greatly improves risk prediction.
Slide 2. Is there clinical evidence that inflammation can be modified by preventive therapies? Keywords: inflammation Slide type: text
Slide 6. Elevated CRP levels in obesity: NHANES 1988–1994 Probably the simplest mechanism to modify CRP levels is weight reduction. In the third U.S. National Health and Nutrition Examination Survey (NHANES III), as individuals increased from normal weight to overweight to frankly obese, the proportion of individuals with elevated CRP dramatically increased. These data are not surprising, because fat cells, or adipocytes, are a major source of IL-6 production and hence will lead to increased levels of CRP. From a preventive cardiologist's standpoint, exercise and weight loss are likely to be fundamental mechanisms by which we can reduce the impact of the inflammatory process. Reference: Visser M, Bouter LM, McQuillan GM, Wener MH, Harris TB. Elevated C-reactive protein levels in overweight and obese adults. JAMA 1999;282:2131-2135. http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10591334&dopt=Abstract Keywords: C-reactive protein, NHANES, obesity Slide type: graph
Slide 7. Effects of weight loss on CRP concentrations in obese healthy women In 83 healthy obese women (mean BMI 33.8 ± 0.4 kg/m 2 , range 28.2–43.8 kg/m 2 ), CRP was positively associated with BMI at baseline (r=0.281, p=0.01). Subjects with CRP below the median of 5.8 mg/L had significantly lower BMI at baseline (33.0 ± 0.5 kg/m 2 ) than subjects with CRP above the median (BMI 34.8 ± 0.6 kg/m 2 ; p=0.02). BMI accounted for 7.7% of variability in baseline CRP (p=0.01). After 12 weeks on a very low fat, energy-restricted diet (mean 5700 ± 60 kJ/d, 14.2 ± 0.2% fat), CRP was reduced by 26% (p<0.001). Average weight loss was 7.9 ± 0.3 kg and was associated with change in CRP. Change in CRP was also correlated with change in total cholesterol (r=0.240, p=0.03) but not changes in low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), or glucose. At 12 weeks, CRP concentration was highly correlated with triglyceride concentration (r=0.287, p=0.009), but not with other lipids or glucose at baseline or 12 weeks. Reference: Heilbronn LK, Noakes M, Clifton PM. Energy restriction and weight loss on very-low-fat diets reduce C-reactive protein concentrations in obese, healthy women. Arterioscler Thromb Vasc Biol 2001;21:968-970. http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11397705&dopt=Abstract Keywords: C-reactive protein, diet, obesity, weight loss Slide type: text
Slide 12. Effect of HRT on hs-CRP: the PEPI study Another preventive therapy that seems to impact upon CRP is hormone-replacement therapy (HRT). The Postmenopausal Estrogen/Progestin Interventions (PEPI) study randomized postmenopausal women to placebo or to four different estrogen or estrogen plus progesterone regimens: conjugated equine estrogens (CEE) 0.625 mg/d, CEE 0.625 mg/d plus medroxyprogesterone acetate (MPA) 10 mg/d for days 1–12 each month (cyclic), CEE 0.625 mg/d plus MPA 2.5 mg/d (continuous), or CEE plus micronized progesterone (MP) 200 mg/d, days 1–12 each calendar month. Regardless of the HRT preparation, CRP levels markedly increased following initiation of HRT. These data have been confirmed elsewhere and have raised the possibility that part of the early thrombotic hazard that might be associated with initiation of HRT may relate in some way to a proinflammatory effect. Reference: Cushman M, Legault C, Barrett-Connor E, Stefanick ML, Kessler C, Judd HL, Sakkinen PA, Tracy RP. Effect of postmenopausal hormones on inflammation‑sensitive proteins: the Postmenopausal Estrogen/Progestin Interventions (PEPI) Study. Circulation 1999;100:717-722. http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10449693&dopt=Abstract Keywords: C-reactive protein, estrogen, PEPI, progesterone Slide type: graph
Moreover, it was also shown in the CARE trial for the first time that statin therapy could lower plasma levels of CRP. This is now known to be a class effect of all statins. It is important to note that the magnitude of CRP reduction associated with statin use is not closely linked to the magnitude of LDL reduction.
Slide 26. Effect of statin therapy on hs-CRP levels at 6 weeks Each statin studied significantly reduced CRP levels. Median percent reduction in hs-CRP did not differ significantly among statins; atorvastatin reduced hs-CRP by a median of 28.3%, pravastatin by 20.3%, and simvastatin by 22.8%. With the respective statins, CRP was reduced in 81.8%, 72.7%, and 81.8% of patients; CRP was reduced with all three statins in 54.6% of patients. Change in CRP level was not significantly correlated with change in LDL-C or HDL-C but was correlated with triglyceride (r=0.59, p=0.005). Reference: Jialal I, Stein D, Balis D, Grundy SM, Adams-Huet B, Devaraj S. Effect of hydroxymethyl glutaryl coenzyme A reductase inhibitor therapy on high sensitive C-reactive protein levels. Circulation 2001;103:1933-1935. http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11306519&dopt=Abstract Keywords: atorvastatin, C-reactive protein, pravastatin, simvastatin, statins Slide type: graph
Slide 29. Effect of bezafibrate with and without fluvastatin on plasma fibrinogen, PAI-1, and CRP in patients with CAD and mixed hyperlipidemia Fluvastatin and bezafibrate, alone and in combination, were evaluated for their effects on fibrinogen, plasminogen activator inhibitor 1 (PAI-1), and CRP in 333 patients with hyperlipidemia (LDL-C 135–250 mg/dL, triglyceride 180–400 mg/dL) and stable angina, prior myocardial infarction, or coronary revascularization. Patients were randomized to receive fluvastatin 40 mg (not shown), bezafibrate 400 mg, bezafibrate 400 mg + fluvastatin 20 mg, or bezafibrate 400 mg + fluvastatin 40 mg for 24 weeks. Plasma fibrinogen was significantly decreased by 9%, 14%, and 16% in the respective bezafibrate treatment groups. PAI-1 and CRP levels did not change with any of the treatment regimens. Reference: Cortellaro M, Cofrancesco E, Boschetti C, Cortellaro F, Mancini M, Mariani M, Paoletti R, on behalf of the FACT study centers. Effects of fluvastatin and bezafibrate combination on plasma fibrinogen, t-plasminogen activator inhibitor and C reactive protein levels in coronary artery disease patients with mixed hyperlipidaemia (FACT study). Thromb Haemost 2000;83:549-553. http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10780315&dopt=Abstract Keywords: bezafibrate, C-reactive protein, FACT, fibrinogen, fluvastatin, PAI-1 Slide type: graph
This slide depicts a schematic of the basic trial design for JUPITER. JUPITER will recruit men aged 55 years and older and women aged 65 years and older, who have no prior history of MI, stroke or myocardial revascularization and who, on initial screening, are found to have LDL-C levels 130 mg/dL and CRP levels 2.0 mg/L. Subjects will be randomized in a double-blind fashion to either rosuvastatin 20mg/day or placebo. All study participants will then be followed over a period of 3 to 4 years for the development of first myocardial infarction, stroke, hospitalization for unstable angina, revascularization procedure, or cardiovascular death. JUPITER has been designed as a large, simple trial to answer definitively whether or not those with low cholesterol levels but high CRP levels should be treated aggressively with statin therapy to prevent first ever cardiovascular events.
The importance of the JUPITER trial is made clear by recent evidence suggesting that CRP is at least as strong a predictor of cardiovascular disease as is LDL cholesterol. As the data from this recent study has been pivotal in leading the Centers for Disease Control and the American Heart Association to issue guidelines on the use of CRP for clinical risk detection, the next several slides will outline the results of this study. In brief, a full lipid panel, traditional risk factors, and hs-CRP levels were measured at baseline among 27,939 initially healthy American women participating in the Women’s Health Study (WHS) who were then followed over an 8 year period and monitored for first ever cardiovascular events.
This slide depicts cardiovascular event-free survival according to baseline quintiles of CRP and LDL-C over 8 years of followup in the WHS. As shown, both CRP (left) and LDL-C (right) are strong predictors of future cardiovascular events. However, since LDL levels do not correlate with CRP levels, both of these markers tend to detect different high risk groups. Thus, a combined approach using both CRP and LDL is needed.
The results of combined LDL and CRP screening are shown in this slide which depicts cardiovascular event-free survival in four groups based upon high or low levels of each marker. As expected, the poorest event-free survival was among those with high LDL and high CRP, and the best event-free survival was those with low LDL and low CRP. However, and of great importance for the JUPITER trial, those with low levels of LDL but high levels of CRP were actually at higher risk than those with high levels of LDL but low levels of CRP. It is important to remember that individuals in the high CRP/low LDL group are generally missed by current screening guidelines. This is the population that is being prospectively studied in the JUPITER trial.
This slide depicts two additional important analysis from the WHS database which establish that CRP levels independently add predictive information above and beyond traditional approaches. The data on the right indicate that at all levels of LDL, knowledge of CRP adds important risk information, even after multivariate adjustment for all available traditional risk factors. The data on the left indicate that at all levels of the Framingham Risk Score, knowledge of CRP also adds important prognostic information. This information is most important for those at intermediate risk, that is between a 5 percent and 20 percent 10-year risk of developing coronary artery disease. This latter group is exactly the group to be recruited for the JUPITER trial.
Another question of active research interest concerns the impact of vascular inflammation and CRP among patients with diabetes and those with the metabolic syndrome.
This issue has also been recently addressed within the Women’s Health Study cohort. As this study has implications for the design of JUPITER, the next several slides review the critical findings of this analysis.
This slide depicts the distribution of CRP levels among 14,719 initially healthy American women participating in the WHS according to the number of components of the metabolic syndrome each woman had at baseline. Components of the metabolic syndrome in women typically include triglycerides 150mg/dL; HDL <50mg/dL; blood pressure 135/85mmHg; obesity as defined by a waist circumference >88cm and abnormal glucose metabolism as defined by fasting glucose 110mg/dL. Individuals possessing any 3 or more of these components are defined as having the metabolic syndrome. The box plots demonstrate median, 25th, and 75th percentile values for CRP, according to the number of components of the metabolic syndrome present. As shown, t here is a strong linear increase in CRP levels across levels of severity of the metabolic syndrome.
However, even among women with the metabolic syndrome at baseline, knowledge of CRP levels has important prognostic information. This slide depicts cardiovascular event-free survival in analyses stratified by CRP levels <1, 1-3 and >3mg/L. As clearly shown, CRP levels added information at all levels of the metabolic syndrome, just as prior data demonstrated that CRP added important information at all levels of LDL and at all levels of the Framingham Risk Score.
In January of 2003, a consensus panel from the American Heart Association and the Centers of Disease Control and Prevention published the first set of guidelines for the use of CRP in clinical settings.
This slide provides the key excerpt from the AHA/CDC Scientific Statement on CRP that was published in January, 2003 encapsulating the essence of how CRP should be applied for clinical cardiovascular risk assessment in primary prevention populations : Measurement of hs-CRP is an independent marker of risk and may be used at the discretion of the physician as part of global coronary risk assessment in adults without known cardiovascular disease. Weight of evidence favors use particularly among those judged at intermediate risk by global risk assessment. Recall that those with an intermediate global risk– a Framingham Score between 5 and 20%/10yrs– defines the population being recruited for participation in the JUPITER trial.
As outlined in a recent clinical overview of CRP, the Centers for Disease Control also established a set of cut points to be used in routine clinical practice. As shown here, levels of CRP < 1mg/L, 1 to 3 mg/L, and > 3 mg/L correspond to low, moderate, and high vascular risk. CRP levels >10mg/L likely may indicate an acute phase response and should be remeasured in 2 to 3 weeks. Values that remain in this range are true positives and again reflect high vascular risk. CRP levels do not require fasting and can be measured at any time of the day.
Inflammation, Infection and Cardiovascular Disease (
Inflammation, Thrombosis, Infection, and CARDIOVASCULAR DISEASE Nathan D Wong, PhD, FACC Professor and Director Heart Disease Prevention Program University of California, Irvine
Beyond Cholesterol: Predicting Cardiovascular Risk In the 21 st Century Cardiovascular Risk Lipids HTN Diabetes Behavioral Hemostatic Thrombotic Inflammatory Genetic
Inflammation and Atherosclerosis <ul><li>Inflammation may determine plaque stability </li></ul><ul><li>- Unstable plaques have increased leukocytic infiltrates </li></ul><ul><li>- T cells, macrophages predominate rupture sites </li></ul><ul><li>- Cytokines and metalloproteinases influence both stability and degradation of the fibrous cap </li></ul><ul><li>Lipid lowering may reduce plaque inflammation </li></ul><ul><li>- Decreased macrophage number </li></ul><ul><li>- Decreased expression of collagenolytic enzymes (MMP-1) </li></ul><ul><li>- Increased interstitial collagen </li></ul><ul><li>- Decreased expression of E-selectin </li></ul><ul><li>- Reduced calcium deposition </li></ul>Libby P. Circulation 1995;91:2844-2850. Ross R. N Engl J Med 1999;340:115-126.
Is there clinical evidence that inflammatory markers predict future coronary events and provide additional predictive information beyond traditional risk factors?
Evaluating Novel Risk Factors for CAD <ul><li>Consistency of prospective data </li></ul><ul><li>Strength of association </li></ul><ul><li>Independence of association </li></ul><ul><li>Improve predictive value </li></ul><ul><li>Standardized measure </li></ul><ul><li>Low variability </li></ul><ul><li>High reproducibility </li></ul><ul><li>Biologic plausibility </li></ul><ul><li>Low cost </li></ul><ul><li>Modifiable </li></ul>
Biomarkers for Venous and Arterial Thrombosis +++ – hs-CRP / SAA / IL-6 / TNF + – Lp(a) ++ – Platelet function ++ – PAI-1: ag +++ – tPA: ag ++ – vWF: ag + – Factor VII +++ – Fibrinogen Arterial Venous Parameter
Biomarkers for Venous and Arterial Thrombosis (cont’d) ++ ++ D-dimer ++ ++ Homocysteine – + Protein S – + Protein C – ++ Anti-thrombin III – ++ Factor VIII – + Prothrombin – ++ Prothrombin mutation – +++ Factor V Leiden Arterial Venous Parameter
Thrombosis and Cardiovascular Risk <ul><li>Thrombus formation is a crucial factor in the precipitation of unstable angina or myocardial infarction, as well as occlusion during or following angioplasty. </li></ul><ul><li>Often preceded by platelet aggregation and activation of the coagulation system. </li></ul><ul><li>A thrombus may develop at sites of only mild to moderate coronary stenosis. The majority of coronary events occur where there is less than 70% stenosis. </li></ul><ul><li>Occlusive coronary thrombosis plays a role in over 80% of myocardial infarctions and about 95% of sudden death victims. </li></ul>
Fibrinogen and Atherosclerosis <ul><li>Promotes atherosclerosis </li></ul><ul><li>Essential component of platelet aggregation </li></ul><ul><li>Relates to fibrin deposited and the size of the clot </li></ul><ul><li>Increases plasma viscosity </li></ul><ul><li>May also have a proinflammatory role </li></ul><ul><li>Measurement of fibrinogen, incl. Test variability, remains difficult. </li></ul><ul><li>No known therapies to selectively lower fibrinogen levels in order to test efficacy in CHD risk reduction via clinical trials. </li></ul>
Fibrinogen and CHD Risk: Epidemiologic Studies <ul><li>Recent meta-analysis of 18 studies involving 4018 CHD cases showed a relative risk of CHD of 1.8 (95% CI 1.6-2.0) comparing the highest vs lowest tertile of fibrinogen levels (mean .35 vs. .25 g/dL) </li></ul><ul><li>ARIC study in 14,477 adults aged 45-64 showed relative risks of 1.8 in men and 1.5 in women, attenuated to 1.5 and 1.2 after risk factor adjustment. </li></ul><ul><li>Scottish Heart Health Study of 5095 men and 4860 women showed fibrinogen to be an independent risk factor for new events--RRs 2.2-3.4 for coronary death and all-cause mortality. </li></ul>
Fibrinogen and CHD Risk Factors <ul><li>Fibrinogen levels increase with age and body mass index, and higher cholesterol levels </li></ul><ul><li>Smoking can reversibly elevated fibrinogen levels, and cessation of smoking can lower fibrinogen. </li></ul><ul><li>Those who exercise, eat vegetarian diets, and consume alcohol have lower levels. Exercise may also lower fibrinogen and plasma viscosity. </li></ul><ul><li>Studies also show statin-fibrate combinations (simvastatin-ciprofibrate) and estrogen therapy to lower fibrinogen. </li></ul>
Other Thrombotic Factors and CHD <ul><li>Mixed reports of coagulation factor VIIc in cardiovascular disease. PROCAM study showed no association with CHD events, CHS also showed no relation to subclinical CVD. </li></ul><ul><li>Endogenous tissue-type plasminogen activator (tPA) shown in some studies to relate to increased cardiovascular risk--Physician’s Health Study showed RR for MI 2.8, stroke 3.5 in those in 5th vs. 1st quintile of tPA. </li></ul><ul><li>Plasminogen activitor inhibitor type 1 (PAI-1) shown associated with increased cardiovascular risk, esp in diabetic patients. </li></ul>
Aspirin and Cardiovascular Risk: Clinical Trial Evidence for Primary Prevention <ul><li>US Physician’s Health Study- 22,071 male physicians - 44% reduction in MI risk, 13% nonsignificant increase in risk of stroke </li></ul><ul><li>British Doctor’s Study of 5139 male physicians showed nonsignificant 3% reduction in MI risk,13% nonsignificant increase in stroke </li></ul><ul><li>Hypertension Optimal Treatment (HOT) study among 18,790 pts w/htn showed 15% reduction in CVD events, 36% reduction in MI </li></ul><ul><li>Women’s Health Study (n=39,876 women aged 45+) randomized to 100 mg asprin/day vs placebo, 10 years follow-up – results recently released and asprin preventive only for stroke (17% reduction overall, p=0.04; 24% ischemic stroke, p<.001); nonfatal MI RR=1.02, CVD death 0.95, ns) (NEJM 2005; 352: 1366-8). </li></ul>
Aspirin and Cardiovascular Risk: Clinical Trial Evidence for Secondary Prevention <ul><li>Antiplatelet Trialists Collaboration of 54,000 patients with cardiovascular disease (10 trials post-MI) showed 31% reduction in MI, 42% reduction in stroke, 13% reduction in total vascular mortality </li></ul><ul><li>International Study of Infarct Survival of 17,187 pts w/evolving MI showed 49% reduction in reinfarction, 26% reduction in nonfatal stroke, and 23% reduction in total vascular mortality </li></ul>
Antiplatelet Therapy: Targets Collagen Thrombin TXA 2 ADP (Fibrinogen Receptor) ADP = adenosine diphosphate, TXA 2 = thromboxane A 2 , COX = cyclooxygenase clopidogrel bisulfate TXA 2 phosphodiesterase ADP Gp IIb/IIIa Activation COX ticlopidine hydrochloride aspirin Gp 2b/3a Inhibitors dipyridamole Schafer AI . Am J Med 1996;101:199–209
Antiplatelet Therapy: Common Oral Agents 1 Topol EJ et al. Circulation. 2003;108:399-406 2 Diener H-C et al. Lancet 2004;364;331-7 3 Plavix® package insert. www.sanofi-synthelabo.us 4 Peters RJ et al. Circulation 2003;108:1682-7 5 Hass WK. NEJM 1989;321:501-7 6 Urban P. Circulation. 1998;98:2126-32 7 Ticlid® package insert. www.rocheusa.com * Clopidogrel is generally given preference over Ticlopidine because of a superior safety profile Thienopyridine Thienopyridine Salicylate Class 1.0% alone 5 1.7-5.5% w/ ASA 6,7 1.0-3.7% alone 2,3 3.0-4.9% w/ ASA 4 2.4-3.3% 1 Major Bleeding Risk (%) 250 mg twice daily 75 mg daily 75-325 mg daily Maintenance Dose Active Drug Pro-Drug Active Drug Formulation Ticlid® Plavix® Aspirin Trade Name Ticlopidine hydrochloride* Clopidogrel bisulfate* Acetylsalicylic acid (ASA)
Aspirin: Mechanism of Action Membrane Phospholipids ARACHIDONIC ACID Prostaglandin H 2 COX-1 Thromboxane A 2 Platelet Aggregation Vasoconstriction Prostacyclin Platelet Aggregation Vasodilitation Aspirin
Aspirin Recommendations Aspirin (75-162 mg daily) for intermediate risk men with a 10 year risk of CHD > 10%. Aspirin (75-162 mg daily) for intermediate risk women with a 10 year risk of CHD > 10%. Aspirin for low risk women with a 10 year risk of CHD<10%. Aspirin (75-325 mg daily) for those with known CHD. Primary Prevention Secondary Prevention I I I IIa IIa IIa IIb IIb IIb III III III I I I IIa IIa IIa IIb IIb IIb III III III I I I IIa IIa IIa IIb IIb IIb III III III IIa IIa IIa IIb IIb IIb III III III B
CRP vs hs-CRP <ul><li>CRP is an acute-phase protein produced by the liver in response to cytokine production (IL-6, IL-1, tumor necrosis factor) during tissue injury, inflammation, or infection. </li></ul><ul><li>Standard CRP tests determine levels which are increased up to 1,000-fold in response to infection or tissue destruction, but cannot adequately assess the normal range </li></ul><ul><li>High-sensitivity CRP (hs-CRP) assays (i.e. Dade Behring) detect levels of CRP within the normal range, levels proven to predict future cardiovascular events. </li></ul>
Potential Mechanisms Linking CRP to Atherothrombosis <ul><li>Confounding by cigarette consumption </li></ul><ul><li>Innocent bystander - Acute phase response </li></ul><ul><li>Cytokine surrogate - IL-6, TNF- , IL-1 </li></ul><ul><li>Direct effects of CRP - Innate immunity - Complement activation - CAM induction </li></ul><ul><li>Prior infection - Chlamydia, H pylori, CMV </li></ul><ul><li>Marker for subclinical atherosclerosis - EBCT / IMT / ABI </li></ul><ul><li>Marker for insulin resistance/ obesity </li></ul><ul><li>Marker for endothelial dysfunction </li></ul><ul><li>Marker for dysmetabolic syndrome </li></ul><ul><li>Marker for plaque vulnerability </li></ul>
hs-CRP and Risk of Future MI in Apparently Healthy Men P <0.001 P <0.001 P =0.03 Quartile of hs-CRP P Trend <0.001 Relative Risk of MI Ridker et al, N Engl J Med. 1997;336:973–979. 1 2 3 4 0 1 2 3
hs-CRP and Risk of Future Stroke in Apparently Healthy Men P <0.02 P =0.02 Relative Risk of Ischemic Stroke P Trend <0.03 Ridker et al, N Engl J Med. 1997;336:973–979. Quartile of hs-CRP 0 1 2 1 2 3 4
hs-CRP as a Risk Factor For Future CVD : Primary Prevention Cohorts 0 1.0 2.0 3.0 4.0 5.0 6.0 Kuller MRFIT 1996 CHD Death Ridker PHS 1997 MI Ridker PHS 1997 Stroke Tracy CHS/RHPP 1997 CHD Ridker PHS 1998,2001 PAD Ridker WHS 1998,2000,2002 CVD Koenig MONICA 1999 CHD Roivainen HELSINKI 2000 CHD Mendall CAERPHILLY 2000 CHD Danesh BRHS 2000 CHD Gussekloo LEIDEN 2001 Fatal Stroke Lowe SPEEDWELL 2001 CHD Packard WOSCOPS 2001 CV Events* Ridker AFCAPS 2001 CV Events* Rost FHS 2001 Stroke Pradhan WHI 2002 MI,CVD death Albert PHS 2002 Sudden Death Sakkinen HHS 2002 MI Relative Risk (upper vs lower quartile) Ridker PM. Circulation 2003;107:363-9
hs-CRP Adds to Predictive Value of TC:HDL Ratio in Determining Risk of First MI Total Cholesterol:HDL Ratio Ridker et al, Circulation. 1998;97:2007–2011. hs-CRP Relative Risk
Risk Factors for Future Cardiovascular Events: WHS 0 1.0 2.0 4.0 6.0 Lipoprotein(a) Homocysteine IL-6 TC LDLC sICAM-1 SAA Apo B TC: HDLC hs-CRP hs-CRP + TC: HDLC Relative Risk of Future Cardiovascular Events Ridker et al, N Engl J Med. 2000;342:836-43
Is there clinical evidence that inflammation can be modified by preventive therapies?
Elevated CRP Levels in Obesity: NHANES 1988-1994 Visser M et al. JAMA 1999;282:2131-2135. Normal Percent with CRP 0.22 mg/dL Overweight Obese
Effects of Weight Loss on CRP Concentrations in Obese Healthy Women <ul><li>83 women (mean BMI 33.8, range 28.2-43.8 kg/m 2 ) placed on very low fat, energy-restricted diet (6.0 MJ, 15% fat) for 12 weeks </li></ul><ul><li>Baseline CRP positively associated with BMI (r=0.281, p=0.01) </li></ul><ul><li>CRP reduced by 26% (p<0.001) </li></ul><ul><li>Average weight loss 7.9 kg, associated with change in CRP </li></ul><ul><li>Change in CRP correlated with change in TC (r=0.240, p=0.03) but not changes in LDL-C, HDL-C, or glucose </li></ul><ul><li>At 12 weeks, CRP concentration highly correlated with TG (r=0.287, p=0.009), but not with other lipids or glucose </li></ul>Heilbronn LK et al. Arterioscler Thromb Vasc Biol 2001;21:968-970.
Effect of HRT on hs-CRP: the PEPI Study 3.0 2.0 1.0 hs-CRP (mg/dL) Months 0 12 36 Cushman M et al. Circulation 1999;100:717-722. 1999 Lippincott Williams & Wilkins. CEE + MPA cyclic CEE + MPA continuous CEE + MP CEE Placebo
Long-Term Effect of Statin Therapy on hs-CRP: Placebo and Pravastatin Groups Pravastatin Placebo Median hs-CRP Concentration (mg/dL) -21.6% ( P =0.004) 0.18 0.19 0.20 0.21 0.22 0.23 0.24 0.25 Baseline 5 Years Ridker et al, Circulation. 1999;100:230-235.
Effect of Statin Therapy on hs-CRP Levels at 6 Weeks hs-CRP (mg/L) Jialal I et al. Circulation 2001;103:1933-1935. 2001 Lippincott Williams & Wilkins. 6 5 4 3 2 1 0 Baseline Prava (40 mg/d) Simva (20 mg/d) Atorva (10 mg/d) *p<0.025 vs. Baseline * * *
Effect of Bezafibrate with and without Fluvastatin on Plasma Fibrinogen, PAI-1, and CRP in Patients with CAD and Mixed Hyperlipidemia Beza 400 mg/d Beza 400 mg/d + fluva 20 mg/d Beza 400 mg/d + fluva 40 mg/d Cortellaro M et al. Thromb Haemost 2000;83:549-553. Change at 24 weeks, % n: 81 Fibrinogen PAI-1 CRP 80 74 70 72 63 83 80 75 P<0.05 vs. baseline * * *
JUPITER Randomized Trial of Rosuvastatin in the Primary Prevention of Cardiovascular Events Among Individuals with Low Levels of LDL-C and Elevated Levels of hs-CRP No History of CAD Men > 55, Women > 65 LDL-C <130 mg/dL hs-CRP >2 mg/L Rosuvastatin (N =7500) Placebo (N =7500) MI Stroke Unstable Angina CVD Death CABG/PTCA 4 week Run-in hs-CRP Lipids hs-CRP LFTs UA hs-CRP LFTs UA Lipids HbA1C Screening Visit 1 Randomization Visit Safety Visit Bi-Annual Follow-Up Visits End of Study Visit hs-CRP LFTs HbA1C Screening Visit 2
Event-Free Survival According to Baseline Quintiles of C-Reactive Protein and LDL Cholesterol 0 2 4 6 8 Years of Follow-Up 0.96 0.97 0.98 0.99 1.00 Quintiles of LDL 0 2 4 6 8 Years of Follow-Up 0.96 0.97 0.98 0.99 1.00 CVD Event-Free Survival Probability Quintiles of CRP Ridker et al, N Engl J Med. 2002;347:1157-1165. 5 4 3 2 1 5 4 3 2 1
1.00 0.99 0.98 0.97 0.96 0.00 0 2 4 6 8 Years of Follow-up Low CRP-low LDL Low CRP-high LDL High CRP-low LDL High CRP-high LDL CV Event-Free Survival Using Combined hs-CRP and LDL-C Measurements Ridker et al, N Engl J Med. 2002;347:1157-1165. Probability of Event-free Survival Median LDL 124 mg/dl Median CRP 1.5mg/l
hs-CRP Adds Prognostic Information at all Levels of LDL-C and at all Levels of the Framingham Risk Score 0 - 1 25 20 15 10 5 0 Relative risk Multivariable relative risk 2 - 4 5 - 9 10-20 130 - 160 <130 >160 Framingham estimate of 10-year risk (%) LDL cholesterol (mg/dL) C-Reactive Protein (mg/L) C-Reactive Protein (mg/L) 1 0 2 3 <1.0 1.0 -3.0 >3.0 Ridker et al, N Engl J Med. 2002;347:1557. <1.0 1.0 -3.0 >3.0
What is the role of hs-CRP with regard to diabetes and the metabolic syndrome?
Plasma hs-CRP Levels According to Severity of the Metabolic Syndrome 0 1 2 3 4 5 0 2 4 6 8 C-reactive protein (mg/L) Number of Components of the Metabolic Syndrome Ridker et al, Circulation 2003;107:391-7
0 2 4 6 8 Years of Follow-Up 0.95 0.96 0.97 0.98 0.99 1.00 CVD Event-Free Survival Probability CRP <1 mg/L CRP 1-3 mg/L CRP >3 mg/L Event Free Survival According to hs-CRP Levels: Analysis Limited to Participants with Metabolic Syndrome at Baseline Ridker et al, Circulation 2003;107:391-7
AHA / CDC Scientific Statement Markers of Inflammation and Cardiovascular Disease: Applications to Clinical and Public Health Practice Circulation January 28, 2003 “Measurement of hs-CRP is an independent marker of risk and may be used at the discretion of the physician as part of global coronary risk assessment in adults without known cardiovascular disease. Weight of evidence favors use particularly among those judged at intermediate risk by global risk assessment”.
Clinical Application of hs-CRP for Cardiovascular Risk Prediction 1 mg/L 3 mg/L 10 mg/L Low Risk Moderate Risk High Risk Acute Phase Response Ignore Value, Repeat Test in 3 weeks >100 mg/L Ridker PM. Circulation 2003;107:363-9
Inflammatory and Infections Agents in CHD <ul><li>Belgian epidemiologic study included 446 of 16307 male workers aged 35-39 who had evidence of CHD vs. 892 controls. </li></ul><ul><li>CRP, but none of the infectious agents (H. pylori, C. pneumoniae, CMV, and EBV) were associated with CHD, even after adjustment for other risk factors. </li></ul>De Backer et al. Atherosclerosis 2002; 160: 457-63.
Infection and CHD - is there a connection? <ul><li>Local or systemic infections resulting from gram negative bacteria such as Chlamydia pneumoniae and Helicobacter pylori, including cytomegalovirus (CMV) have been implicated in atheroscelosis </li></ul><ul><li>While several case control studies have shown increased titers of C.pneumoniae and H. Pylori in those with vs. without CHD, convincing evidence from prospective studies is lacking. </li></ul>
Prospective Studies of CHD and Infectious Pathogens <ul><li>Physician’s Health Study (nested case-control) shows RR 1.1 (0.8-1.5) for C. Pneumoniae, 0.94 (0.7-1.2) for cytomegalovirus, and 0.72 (0.6-0.9) for Herpes simplex virus. </li></ul><ul><li>H. pylori also shows mixed results. Whincup showed a nonsignificant 1.3 OR when adjusted for other risk factors, the large ARIC study showed no relation, and the Caerphilly Prospective study showed RR=1.05 in 1796 men followed 14 years. </li></ul>
Other Studies of Infectious Agents <ul><li>In South Asian persons with CHD vs. controls, C. pneumoniae specific IgG antibody was seropositive in similar proportions; risk factors appeared to mediate any relations (Mendis et al. Int J Cardiol 2001; 79: 191-6). </li></ul><ul><li>Cross-sectional survey of 704 individuals of C. pneumoniae and CMV with risk factors did nto show significant associations (Danesh et al., J Cardiovasc Risk 1999; 6: 387-90). </li></ul><ul><li>Meta-analysis of 24 articles involving H. pylori infection and CHD showed a pooled odds ratio of 1.55 (95% CI: 1.38-1.74) (p<0.001), suggested a weak relation, but high hetrogeneity between studies precludes clear demonostration (Pellicano et al., Eur J Epidemiol 1999; 15: 611-9). </li></ul><ul><li>ARIC Study failed to show clear relation between IgG antibodies for C. pneumoniae and incident CHD occurring over average 3.3 years. (Nieto et al. Am J Epidemiol 1999; 150: 149-56). </li></ul>
Clinical Trial Evidence for Antibiotic Treatment and Prevention of CVD <ul><li>ACADEMIC Study of 302 patients with CHD seropositive to C. Pneumoniae randomized to azithromycin 500 mg/wk or placebo for 3 months showed no significant treatment difference (HR=0.89, p=0.74) for recurrent events (Muhlestein et al., Circulation 2000; 102: 1755-60). </li></ul><ul><li>AZACS Multicenter study of 1439 pts with unstable angina randomized to 250 mg azithromycin/day for up to 6 months showed no significant benefit for death, recurrent MI, or recurrent ischemia (Cercek et al., Lancet 2003; 361: 809-13). </li></ul><ul><li>WIZARD trial of 7,747 pts post-MI randomized to 12 week of therapy with azithromycin or placebo showed no significant reduction in reinfarction, revascularization, hospitalization for angina, or death (O’Connor et al., JAMA 2003; 290: 1459-66). </li></ul>
Infectious Agents and the Future <ul><li>Individuals with greater infectious burdens may be at greater risk, because they are older, have poorer health habits, less access to care. </li></ul><ul><li>Observed associations often may be due to selection biases or confounding from age and other factors </li></ul><ul><li>Prospective clinical trials under way examining role of certain antibiotics such as azithromycin on reduction of recurrent events in CHD patients. </li></ul><ul><li>Until these data are available, no role for measurement or treatment of infectious burden. </li></ul>