Epidemiology of Inflammatory Markers and CHD: Evidence for High-Sensitivity C-Reactive Protein Paul M. Ridker, MD, MPH

Beyond Cholesterol: Predicting Cardiovascular Risk In the 21 st Century Cardiovascular Risk Lipids HTN Diabetes BehavioralBehavioral Hemostatic Thrombotic InflammatoryInflammatoryGeneticGenetic

Total Cholesterol Distribution: CHD vs Non-CHD Population Castelli WP. Atherosclerosis. 1996;124(suppl):S1-S9. 1996 Reprinted with permission from Elsevier Science. 35% of CHD Occurs in People with TC<200 mg/dL Total Cholesterol (mg/dL) No CHD CHD Framingham Heart Study—26-Year Follow-up

Inflammation and Atherosclerosis Inflammation may determine plaque stability - Unstable plaques have increased leukocytic infiltrates - T cells, macrophages predominate rupture sites - Cytokines and metalloproteinases influence both stability and degradation of the fibrous cap Lipid lowering may reduce plaque inflammation - Decreased macrophage number - Decreased expression of collagenolytic enzymes (MMP-1) - Increased interstitial collagen - Decreased expression of E-selectin - Reduced calcium deposition Libby P. Circulation 1995;91: Ross R. N Engl J Med 1999;340:

Is there clinical evidence that inflammatory markers predict future coronary events and provide additional predictive information beyond traditional risk factors?

hs-CRP and Risk of Future MI in Apparently Healthy Men Ridker PM et al. N Engl J Med 1997;336: <0.055 Relative Risk of MI P = 0.03 Quartile of hs-CRP (range, mg/dL) – – >0.211 P < P Trend <0.001

hs-CRP and Risk of Future MI: Analysis Stratified by Smoking Status Ridker PM et al. N Engl J Med 1997;336: Relative Risk of Future MI Quartile of CRP 234 All Patients Nonsmokers

hs-CRP and Risk of Future MI: Analysis Stratified by Year of Follow-up Ridker PM et al. N Engl J Med 1997;336: 1997 Massachusetts Medical Society. All rights reserved. 0 – 2 Relative Risk (per Quartile) Years of Study Follow-up 2 – 44 – 66+

hs-CRP and Risk of Future Stroke in Apparently Healthy Men Ridker PM et al. N Engl J Med 1997;336: <0.055 Relative Risk of Ischemic Stroke Quartile of hs-CRP (range, mg/dL) – – >0.211 P =0.02 P Trend <0.03

hs-CRP and Risk of Developing PVD in Apparently Healthy Men Ridker PM et al. Circulation 1998;97: 1998 Lippincott Williams & Wilkins. None hs-CRP (mg/dL) Intermittent Claudication Peripheral Artery Surgery

hs-CRP and Risk of Future Cardiovascular Events in Apparently Healthy Women Ridker PM et al. Circulation 1998;98: <0.15 Relative Risk Quartile of hs-CRP (range, mg/dL) – – >0.73 P Trend <0.002 Any Event MI or Stroke

hs-CRP and Risk of Future Cardiovascular Events in Apparently Healthy Women: Low-Risk Subgroups Ridker PM et al. Circulation 1998;98: <0.15 Relative Risk Quartile of hs-CRP (range, mg/dL) – – >0.73 No hypertension No hyperlipidemia No current smoking No diabetes No family history

hs-CRP and Coronary Heart Disease in Initially Healthy Men: MONICA–Augsburg Cohort Koenig W et al. Circulation 1999;99: <0.6 Rate Ratio (Age Adjusted) Quartile of CRP (mg/dL) 2 0.6– – –4.5 5 >4.5

hs-CRP as a Risk Factor for Future CVD Relative Risk (upper vs lower quartile) CHD Death MI Stroke CHD PVD CVD CHD 0 MRFIT ( Kuller 1996) PHS (Ridker 1997) CHS/RHPP (Tracy 1997) PHS (Ridker 1998) WHS (Ridker 1998, 2000) MONICA (Koenig 1999) Helsinki (Roivainen 2000) Caerphilly (Mendall 2000) Britain (Danesh 2000)

hs-CRP Adds to the Predictive Value of Total Cholesterol in Determining Risk of First MI Ridker PM et al. Circulation 1998;97: 1998 Lippincott Williams & Wilkins. Adjusted Relative Risk CRP >75 th percentile TC >75 th percentile –+–+ –+–+ P = 0.02 P = P = 0.002

hs-CRP Adds to Predictive Value of TC:HDL Ratio in Determining Risk of First MI Ridker PM et al. Circulation 1998;97: 1998 Lippincott Williams & Wilkins. Total Cholesterol:HDL Ratio hs-CRP

Quartile of TC: HDL-C Quartile of hs-CRP hs-CRP, Lipids, and Risk of Future Coronary Events: Women's Health Study (WHS) Ridker PM et al. N Engl J Med 2000;342:

Relative Risks for First MI for Baseline sICAM-1 >260 ng/dL Ridker PM et al. Lancet 1998;351: 1998 Reprinted with permission from Elsevier Science. Years of Study Follow-up 0– –22–44–8 Relative Risk

Predictivity of Interleukin-6 on CV Risk in Women Ridker PM et al. N Engl J Med 2000;342: 2000 Massachusetts Medical Society. All rights reserved High Medium Low High Medium Low Interleukin-6 Total cholesterol

Plasma Concentration of TNF- and Risk of Recurrent Coronary Events Ridker PM et al. Circulation 2000;101: 2000 Lippincott Williams & Wilkins –2.47 (1 st –50 th ) Relative Risk TNF- Concentration, pg/mL (percentile of control distribution) 2.48–3.05 (51 st –75 th ) 3.06–4.17 (76 th –95 th ) (>95 th )

Risk Factors for Future Cardiovascular Events: WHS Relative Risk of Future Cardiovascular Events 0 Ridker PM et al. N Engl J Med 2000;342: Lipoprotein(a) Homocysteine IL-6 TC LDL-C sICAM-1 SAA Apo B TC:HDL-C hs-CRP hs-CRP + TC:HDL-C

Predictive Value of CRP and Other Inflammatory Markers: LDL <130 mg/dL Ridker PM et al. N Engl J Med 2000;342: Relative Risk of Future Coronary Events Quartile of Inflammatory Marker hs-CRP 234 SAA IL-6 sICAM-1

Potential Mechanisms Linking CRP to Atherothrombosis Confounding by cigarette consumption Innocent bystander - Acute phase response Cytokine surrogate - IL-6, TNF-, IL-1 Direct effects of CRP - Innate immunity - Complement activation - CAM induction Prior infection - Chlamydia, H pylori, CMV Marker for subclinical atherosclerosis - EBCT / IMT / ABI Marker for insulin resistance/ obesity Marker for endothelial dysfunction Marker for dysmetabolic syndrome Marker for plaque vulnerability

Evaluating Novel Risk Factors for CAD Consistency of prospective data Strength of association Independence of association Improve predictive value Standardized measure Low variability High reproducibility Biologic plausibility Low cost Modifiable

CRP vs hs-CRP 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. Standard CRP 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 High-sensitivity CRP 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.

hs-CRP: Automated Commercial Latex- Enhanced Assay (Dade) vs Validated in- House ELISA Dade hs-CRP (Latex, In[mg/L]) hs-CRP (ELISA, In[mg/L]) (In-house) Rifai N et al. Clin Chem 1999;45: r = 0.93 P < 0.001

Age-Adjusted Correlation Coefficients for hs-CRP Levels and Lipid Parameters over a 5-Year Follow-up Period ParameterrP hs-CRP Total Cholesterol LDL-C HDL-C Triglycerides Ridker PM et al. Circulation 1999;100:

Population Distribution of hs-CRP in Apparently Healthy American Men and Women QuintileRange (mg/dL)Risk Estimate 10.01–0.069Low 20.07–0.11Mild 30.12–0.19Moderate 40.20–0.38High 50.39–1.50Highest Ridker PM et al. Circulation. In press.

Biomarkers for Venous and Arterial Thrombosis ParameterVenousArterial Fibrinogen–+++ Factor VII–+ vWF: ag–++ tPA: ag–+++ PAI-1: ag–++ Platelet function–++ Lp(a)–+ hs-CRP / SAA / IL-6 / TNF–+++

Biomarkers for Venous and Arterial Thrombosis (cont’d) ParameterVenousArterial Factor V Leiden+++– Prothrombin mutation++– Prothrombin+– Factor VIII++– Anti-thrombin III++– Protein C+– Protein S+– Homocysteine++ D-dimer++

Assessment of the Clinical Utility of Novel Markers of Cardiovascular Risk Marker Assay Conditions Standardized? Prospective Studies Consistent? Additive to TC and HDL- C? Lp(a)–+/– Homocysteine++/– tPA and PAI-1+/–+ Fibrinogen+/–++ hs-CRP+++ Ridker PM et al. Ann Intern Med 1999;130: