Inflammation, Thrombosis, Infection, and CARDIOVASCULAR DISEASE Nathan D Wong, PhD, FACC Professor a

1
Inflammation, Thrombosis, Infection, and
CARDIOVASCULAR DISEASENathan D Wong, PhD,
FACCProfessor and DirectorHeart Disease
Prevention ProgramUniversity of California,
Irvine
2
Beyond Cholesterol Predicting Cardiovascular
Risk In the 21st Century
Cardiovascular Risk
3
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 1995912844-2850. Ross R.
N Engl J Med 1999340115-126.
4
Is there clinical evidence that inflammatory
markers predict future coronary events and
provide additional predictive information beyond
traditional risk factors?
5
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

6
Biomarkers for Venous and Arterial Thrombosis
7
Biomarkers for Venous and Arterial Thrombosis
(contd)
8
Thrombosis and Cardiovascular Risk

• Thrombus formation is a crucial factor in the
  precipitation of unstable angina or myocardial
  infarction, as well as occlusion during or
  following angioplasty.
• Often preceded by platelet aggregation and
  activation of the coagulation system.
• 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.
• Occlusive coronary thrombosis plays a role in
  over 80 of myocardial infarctions and about 95
  of sudden death victims.

9
Fibrinogen and Atherosclerosis

• Promotes atherosclerosis
• Essential component of platelet aggregation
• Relates to fibrin deposited and the size of the
  clot
• Increases plasma viscosity
• May also have a proinflammatory role
• Measurement of fibrinogen, incl. Test
  variability, remains difficult.
• No known therapies to selectively lower
  fibrinogen levels in order to test efficacy in
  CHD risk reduction via clinical trials.

10
Fibrinogen and CHD Risk Epidemiologic Studies

• 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)
• 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.
• 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.

11
Fibrinogen and CHD Risk Factors

• Fibrinogen levels increase with age and body
  mass index, and higher cholesterol levels
• Smoking can reversibly elevated fibrinogen
  levels, and cessation of smoking can lower
  fibrinogen.
• Those who exercise, eat vegetarian diets, and
  consume alcohol have lower levels. Exercise may
  also lower fibrinogen and plasma viscosity.
• Studies also show statin-fibrate combinations
  (simvastatin-ciprofibrate) and estrogen therapy
  to lower fibrinogen.

12
Other Thrombotic Factors and CHD

• 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.
• Endogenous tissue-type plasminogen activator
  (tPA) shown in some studies to relate to
  increased cardiovascular risk--Physicians Health
  Study showed RR for MI 2.8, stroke 3.5 in those
  in 5th vs. 1st quintile of tPA.
• Plasminogen activitor inhibitor type 1 (PAI-1)
  shown associated with increased cardiovascular
  risk, esp in diabetic patients.

13
Aspirin and Cardiovascular Risk Clinical Trial
Evidence for Primary Prevention

• US Physicians Health Study- 22,071 male
  physicians - 44 reduction in MI risk, 13
  nonsignificant increase in risk of stroke
• British Doctors Study of 5139 male physicians
  showed nonsignificant 3 reduction in MI risk,13
  nonsignificant increase in stroke
• Hypertension Optimal Treatment (HOT) study among
  18,790 pts w/htn showed 15 reduction in CVD
  events, 36 reduction in MI
• Womens Health Study (n39,876 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, p0.04 24 ischemic stroke, plt.001)
  nonfatal MI RR1.02, CVD death 0.95, ns) (NEJM
  2005 352 1366-8).

14
Aspirin and Cardiovascular Risk Clinical Trial
Evidence for Secondary Prevention

• 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
• 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

15
Antiplatelet Therapy Targets
dipyridamole
clopidogrel bisulfate
ticlopidine hydrochloride
phosphodiesterase
ADP
ADP
Gp 2b/3a Inhibitors
CollagenThrombinTXA2
Gp IIb/IIIa
Activation
(Fibrinogen Receptor)
COX
TXA2
aspirin
ADP adenosine diphosphate, TXA2 thromboxane
A2, COX cyclooxygenase
Schafer AI. Am J Med 1996101199209
16
Antiplatelet Therapy Common Oral Agents
1Topol EJ et al. Circulation. 2003108399-406 2Di
ener H-C et al. Lancet 2004364331-7 3Plavix
package insert. www.sanofi-synthelabo.us 4Peters
RJ et al. Circulation 20031081682-7 5Hass WK.
NEJM 1989321501-7 6Urban P. Circulation.
1998982126-32 7Ticlid package insert.
www.rocheusa.com
Clopidogrel is generally given preference over
Ticlopidine because of a superior safety profile
17
Aspirin Mechanism of Action
Membrane Phospholipids
ARACHIDONIC ACID
Aspirin
COX-1
Prostaglandin H2
Thromboxane A2 ? Platelet Aggregation Vasoconstric
tion
Prostacyclin ? Platelet Aggregation Vasodilitation
18
Aspirin Recommendations
Primary Prevention
Aspirin (75-162 mg daily) for intermediate risk
men with a 10 year risk of CHD gt10. Aspirin
(75-162 mg daily) for intermediate risk women
with a 10 year risk of CHD gt10. Aspirin for
low risk women with a 10 year risk of
CHDlt10. Aspirin (75-325 mg daily) for those
with known CHD.
Secondary Prevention
19
Rader, NEJM 2000 343 1181.
20
P. Ridker
21
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 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 (hs-CRP) assays (i.e. Dade
  Behring) detect levels of CRP within the normal
  range, levels proven to predict future
  cardiovascular events.

22
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

23
hs-CRP and Risk of Future MI in Apparently
Healthy Men
P Trend lt0.001
Plt0.001
Plt0.001
P0.03
Relative Risk of MI
1
2
3
4
Quartile of hs-CRP
Ridker et al, N Engl J Med. 1997336973979.
24
hs-CRP and Risk of Future Stroke in Apparently
Healthy Men
P Trend lt0.03
Plt0.02
P0.02
2
Relative Risk of Ischemic Stroke
1
0
1
2
3
4
Quartile of hs-CRP
Ridker et al, N Engl J Med. 1997336973979.
25
hs-CRP as a Risk Factor For Future CVD Primary
Prevention Cohorts
Kuller MRFIT 1996 CHD Death Ridker PHS
1997 MI Ridker PHS 1997 Stroke Tracy
CHS/RHPP 1997 CHD Ridker PHS 1998,2001 PAD Ridke
r 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
0 1.0 2.0 3.0 4.0 5.0 6.0
Relative Risk (upper vs lower quartile)
Ridker PM. Circulation 2003107363-9
26
hs-CRP Adds to Predictive Value of TCHDL Ratio
in Determining Risk of First MI
Relative Risk
hs-CRP
Total CholesterolHDL Ratio
Ridker et al, Circulation. 19989720072011.
27
Risk Factors for Future Cardiovascular Events
WHS
Lipoprotein(a) Homocysteine IL-6 TC LDLC sICA
M-1 SAA Apo B TC HDLC hs-CRP hs-CRP TC
HDLC
0 1.0 2.0 4.0 6.0
Relative Risk of Future Cardiovascular Events
Ridker et al, N Engl J Med. 2000342836-43
28
Is there clinical evidence that inflammation can
be modified by preventive therapies?
29
Elevated CRP Levels in Obesity NHANES 1988-1994
Percent with CRP ?0.22 mg/dL
Normal
Overweight
Obese
Visser M et al. JAMA 19992822131-2135.
30
Effects of Weight Loss on CRPConcentrations in
Obese Healthy Women

• 83 women (mean BMI 33.8, range 28.2-43.8 kg/m2)
  placed on very low fat, energy-restricted diet
  (6.0 MJ, 15 fat) for 12 weeks
• Baseline CRP positively associated with BMI
  (r0.281, p0.01)
• CRP reduced by 26 (plt0.001)
• Average weight loss 7.9 kg, associated with
  change in CRP
• Change in CRP correlated with change in TC
  (r0.240, p0.03) but not changes in LDL-C,
  HDL-C, or glucose
• At 12 weeks, CRP concentration highly correlated
  with TG (r0.287, p0.009), but not with other
  lipids or glucose

Heilbronn LK et al. Arterioscler Thromb Vasc Biol
200121968-970.
31
Effect of HRT on hs-CRP the PEPI Study
3.0 2.0 1.0
CEE MPA cyclic
CEE MPA continuous
CEE MP
CEE
hs-CRP (mg/dL)
Placebo
0
12
36
Months
Cushman M et al. Circulation 1999100717-722. ?19
99 Lippincott Williams Wilkins.
32
Long-Term Effect of Statin Therapy on hs-CRP
Placebo and Pravastatin Groups
Placebo
0.25
0.24
0.23
-21.6 (P0.004)
Median hs-CRP Concentration (mg/dL)
0.22
0.21
0.20
Pravastatin
0.19
0.18
Baseline
5 Years
Ridker et al, Circulation. 1999100230-235.
33
Effect of Statin Therapy on hs-CRP Levels at 6
Weeks
6 5 4 3 2 1 0
plt0.025 vs. Baseline
hs-CRP (mg/L)
Baseline
Prava(40 mg/d)
Simva(20 mg/d)
Atorva(10 mg/d)
Jialal I et al. Circulation 20011031933-1935. ?2
001 Lippincott Williams Wilkins.
34
Effect of Bezafibrate with and without
Fluvastatin on Plasma Fibrinogen, PAI-1, and CRP
in Patients with CAD and Mixed Hyperlipidemia
Fibrinogen
PAI-1
CRP
n
81
80
74
Change at 24 weeks,
70
72
63
83
80
75

Plt0.05 vs. baseline


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
200083549-553.
35
JUPITERRandomized Trial of Rosuvastatin in the
Primary Prevention of Cardiovascular Events Among
Individuals with Low Levels of LDL-Cand Elevated
Levels of hs-CRP
MI Stroke Unstable Angina CVD Death CABG/PTCA
Rosuvastatin (N 7500) Placebo (N 7500)
No History of CAD Men gt 55, Women gt 65 LDL-C
lt130 mg/dL hs-CRP gt2 mg/L
4 weekRun-in
Screening Visit 1
Randomization Visit
Safety Visit
Bi-Annual Follow-Up Visits
End of Study Visit
Screening Visit 2
hs-CRP Lipids
hs-CRP LFTs UA
hs-CRP LFTs UA Lipids HbA1C
hs-CRP LFTs HbA1C
36
N Engl J Med. 20023471157-1165
37
Event-Free Survival According to Baseline
Quintiles of C-Reactive Protein and LDL
Cholesterol
Quintiles of LDL
Quintiles of CRP
1.00
1.00
1
0.99
0.99
1
2
2
3
0.98
0.98
3
CVD Event-Free Survival Probability
4
4
0.97
0.97
5
5
0.96
0.96
0
2
4
6
8
0
2
4
6
8
Years of Follow-Up
Years of Follow-Up
Ridker et al, N Engl J Med. 20023471157-1165.
38
CV Event-Free Survival Using Combined hs-CRP and
LDL-C Measurements
Median LDL 124 mg/dl Median CRP 1.5mg/l
1.00
Low CRP-low LDL
0.99
Low CRP-high LDL
0.98
Probability of Event-free Survival
High CRP-low LDL
0.97
0.96
High CRP-high LDL
0.00
0
2
4
6
8
Years of Follow-up
Ridker et al, N Engl J Med. 20023471157-1165.
39
hs-CRP Adds Prognostic Information at all Levels
of LDL-C and at all Levels of the Framingham
Risk Score
lt1.0
1.0-3.0
gt3.0
lt1.0
1.0-3.0
gt3.0
C-Reactive Protein (mg/L)
C-Reactive Protein (mg/L)
3
25
20
2
15
Relative risk
Multivariable relative risk
10
1
5
0
0
0-1
2-4
5-9
10-20
130-160
lt130
gt160
Framingham estimate of 10-year risk ()
LDL cholesterol (mg/dL)
Ridker et al, N Engl J Med. 20023471557.
40
What is the role of hs-CRP with regard to
diabetes and the metabolic syndrome?
41

• Circulation. 2003107391-397.

42
Plasma hs-CRP Levels According to Severity of the
Metabolic Syndrome
8
6
C-reactive protein (mg/L)
4
2
0
0
1
2
3
4
5
Number of Components of the Metabolic Syndrome
Ridker et al, Circulation 2003107391-7
43
Event Free Survival According to hs-CRP Levels
Analysis Limited to Participants with Metabolic
Syndrome at Baseline
1.00
0.99
0.98
CVD Event-Free Survival Probability
CRP lt1 mg/L
0.97
CRP 1-3 mg/L
0.96
CRP gt3 mg/L
0.95
0
2
4
6
8
Years of Follow-Up
Ridker et al, Circulation 2003107391-7
44
(No Transcript)
45
AHA / CDC Scientific StatementMarkers of
Inflammation and Cardiovascular
Disease Applications to Clinical and Public
Health PracticeCirculation January 28,
2003Measurement 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.
46
Clinical Application of hs-CRP forCardiovascular
Risk Prediction
3 mg/L
10 mg/L
gt100 mg/L
1 mg/L
Low Risk
Moderate Risk
High Risk
Acute Phase Response Ignore Value, Repeat Test in
3 weeks
Ridker PM. Circulation 2003107363-9
47
Inflammatory and Infections Agents in CHD

• Belgian epidemiologic study included 446 of 16307
  male workers aged 35-39 who had evidence of CHD
  vs. 892 controls.
• 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.

De Backer et al. Atherosclerosis 2002 160
457-63.
48
Infection and CHD - is there a connection?

• Local or systemic infections resulting from gram
  negative bacteria such as Chlamydia pneumoniae
  and Helicobacter pylori, including
  cytomegalovirus (CMV) have been implicated in
  atheroscelosis
• 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.

49
Prospective Studies of CHD and Infectious
Pathogens

• Physicians 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.
• 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 RR1.05 in 1796 men followed 14 years.

50
Other Studies of Infectious Agents

• 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).
• 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).
• 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) (plt0.001), suggested a
  weak relation, but high hetrogeneity between
  studies precludes clear demonostration (Pellicano
  et al., Eur J Epidemiol 1999 15 611-9).
• 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).

51
Clinical Trial Evidence for Antibiotic Treatment
and Prevention of CVD

• 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
  (HR0.89, p0.74) for recurrent events
  (Muhlestein et al., Circulation 2000 102
  1755-60).
• 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).
• 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 (OConnor et al., JAMA 2003 290 1459-66).

52
Infectious Agents and the Future

• Individuals with greater infectious burdens may
  be at greater risk, because they are older, have
  poorer health habits, less access to care.
• Observed associations often may be due to
  selection biases or confounding from age and
  other factors
• Prospective clinical trials under way examining
  role of certain antibiotics such as azithromycin
  on reduction of recurrent events in CHD patients.
• Until these data are available, no role for
  measurement or treatment of infectious burden.