Basics
Description
- Risk factors are features that increase risk of atherosclerotic coronary heart disease (CHD).
- Long-term exposure to CHD risk factors increases risk of clinical manifestations cardiovascular and cerebrovascular disease.
CHD risk factors predict cardiovascular events in persons >65. Risk factor treatment reduces CVD events.
- Most CHD risk factors are manifest in childhood and young adulthood.
- Healthy lifestyle habits early in life can help prevent or control CHD risk factors and reduce future CVD events.
- Moderate changes in lipid levels are common in pregnancy. Severe hypertriglyceridemia can be treated with lifestyle and omega-3 fatty acid therapy. If needed, pharmacologic therapy can be used with caution.
- Avoid therapy for dyslipidemia (DLP) and HTN that may be harmful to fetus: Statins, ACE inhibitors, ARBs. Avoid aspirin in 3rd trimester. Base use of any medication in pregnancy on potential risk-benefit.
Epidemiology
- CHD risk factors contribute to the worldwide epidemic of CHD.
- CVD is the leading cause of death in men >35 and women >45.
- DM, smoking, HTN, and DLP explain majority of risk for CHD events.
- Approximately 20% of CHD risk is unexplained by traditional risk factors.
Incidence
- DM: Incidence has increased 90% from 1997 to 2007.
- Smoking: >1.8 million Americans became daily smokers in 1996, with 66% <18 yr of age.
- HTN: 4-yr incidence of HTN among Framingham adults, 20-69 yr of age, is reported to be 46%.
Prevalence
- Many risk factors increase with age
- DM: Present in 8% of adults >20; 18% of adults >60.
- Obesity: More than 1/3 of adults are overweight or obese.
- Smoking: Rates have decreased over the past 3 decades. 44.5 million American adults (20%) now smoke (<1/2 of prevalence in 1965).
- Smoking: Varies in teenagers from 28% in American Indians to only 5% in Japanese Americans.
- HTN: Prevalence is increasing despite slight increase in treatment and control.
- DLP: 42% of men and 48% of women, non-Hispanic white adults >20, have total cholesterol >200 mg/dL.
- CHD prevalence at autopsy decreased from 1981-1995 in Olmsted County, MN, but may be increasing since then.
Risk Factors
- Major modifiable risk factors:
- Cigarette smoking
- HTN (>140/90 mm Hg)
- DLP: LDL cholesterol >130 mg/dL, low
- HDL cholesterol <40 mg/dL
- Physical inactivity
- Obesity (BMI >30 kg/m2)
- DM (considered CAD equivalent)
- Other risk factors:
- Age: males >50, females >60
- Family history of early CVD (1st-degree male relative <55, 1st-degree female relative <65)
- Male gender
- Low socioeconomic status
- Diet high in saturated and trans fat
- Estrogen deficiency
- Psychosocial factors: Depression, social isolation (-) and optimism (+).
- Hypertriglyceridemia (>150 mg/dL)
- Elevated lipoprotein (a)
- Other potential risk indicators:
- Inflammatory markers (hs-CRP, others)
- Thrombotic factors (fibrinogen, others)
- Impaired endothelial function
- Subclinical cardiovascular disease: coronary calcification, elevated ankle-brachial index (ABI), abnormal carotid interna-media thickness (CIMT)
- Risk factors can be used to estimate a person's risk of future CHD events (See references section).
Genetics
Genetic links to CAD risk factors and to CAD are being studied and include:
- Family history of heart disease
- Familial dyslipidemia syndromes
- Elevated lipoprotein (a)
General Prevention
- Therapeutic lifestyle change includes healthy dietary and exercise habits, and smoking cessation
- Medical therapy targeting control of HTN, DLP, and DM
Pathophysiology
- Risk factors cause endothelial injury, leading to subclinical atheroma.
- Continued exposure to risk factors leads to a disruption of atheroma, thrombosis, and clinical events.
Etiology
- CHD risk factors are due to genetic and environmental influences.
- Environmental factors include dietary habits (saturated fat, sodium, alcohol, and excessive calorie intake, for example), physical activity habits, and body composition (excessive body fat).
Associated Conditions
CHD risk factors may also be associated with risk of dementia, erectile dysfunction, and certain cancers (colon, breast, and prostate).
Diagnosis
History
- Dietary and physical activity habits
- Tobacco exposure
- Family history of CVD
- Past history of HTN, DM, DLP, CVD
Physical Exam
- BP, both arms
- BMI, waist circumference
- Skin findings of hyperlipidemia (xanthoma, xanthelasma, arcus senilis)
- Carotid and abdominal arterial exam for evidence of bruit
- Funduscopic exam for stigmata of HTN and diabetic retinopathy
Tests
Lab
Lab
- Fasting lipid profile: total cholesterol,
- TSH, HDL cholesterol, LDL cholesterol (calculated), and non- HDL cholesterol (total - HDL cholesterol)
- Lab tests related to DLP, HTN, and DM (creatinine, potassium, ALT, "Aminotransferases (AST, ALT)"¯, AST, fasting glucose, hemoglobin A1C).
LabFollowup
- Assess response to treatment: Lipid profile 2-3 mo after initiation of treatment; serum potassium and creatinine 2-4 wk after starting ACE inhibitor/ARB agent; hemoglobin A1C 3 mo after starting DM treatment.
- Consider novel lipid measurements: eg, lipoprotein(a), LDL particle number), or inflammatory markers (hs-CRP, etc.)
Imaging
Not applicable for initial risk factor assessment
ImagingFollowup
- Consider coronary calcification CT scan or carotid US (IMT) for persons at intermediate risk of CVD.
- Consider EKG and/or echo to assess LVH in persons with HTN
Surgery
Consider ambulatory BP monitor to assess BP and other tests to assess cardiovascular risk (ankle-brachial index, exercise ECG, cardiopulmonary exercise test).
Differential Diagnosis
- Assess secondary causes of HTN:
- Renovascular disease
- Endocrine disorders
- Sleep apnea
- Assess secondary causes of DLP:
- Hypothyroidism
- Liver disease
- Renal disease
Treatment
Medication
- Elevated LDL cholesterol:
- *Statins (HMG Co-A reductase inhibitors)
- *Nicotinic acid
- **Ezetimibe
- **Plant stanols/sterols
- **Bile acid resins
- Elevated triglyceride level:
- *Fibrates
- *Nicotinic acid
- *Ī©-3 fatty acids
- DM:
- *Metformin
- *Thiazolidinediones
- *Ī±-Glucosidase inhibitors
- ** Insulin secretogogues:
- §Sulfonylureas
- §Meglitinides
- ** Insulin (1st-line for Type 1 DM)
- HTN:
- *Thiazide diuretics
- *ACE inhibitors
- *ARBs
- **β-Blockers
- **Calcium channel blockers
Additional Treatment
General Measures
- Therapeutic lifestyle change:
- Physical activity, >30 min of brisk activity, ≥5 days/wk; strength training, ≥30 min/wk.
- Healthy nutrition habits, ≥5 servings of fruits/vegetables, whole grains, lean protein, low intake of saturated fat, trans fat, and sodium; modest intake of unsaturated fats
- Smoking cessation
- Restrict or moderate alcohol intake
- Maintain ideal weight, BMI 19-25 kg/m2
- General CVD risk reduction: The USPSTF recommends aspirin for men aged 45-79 and for women aged 55-79 when potential benefit (reduced risk of CVD event) outweighs the potential bleeding risk.
Issues for Referral
- Consider referral to specialized center for patients with complex HTN, DLP, or DM.
- LDL apheresis (consider for very high LDL cholesterol not controlled with drug therapy)
Additional Therapies
DLP: Plant stanols/sterols, oat bran, psyllium fiber, red yeast rice
Surgery
Not applicable
In-Patient Considerations
Not applicable
Ongoing Care
Follow-Up Recommendations
Patient Monitoring
- Monitor adherence, response to therapy.
- Monitor potential side effects of medications (eg, Statin-Induced myalgias).
- Assess attainment of treatment goals.
- DLP: Monitor liver enzymes if patient is on a statin drug, niacin, or a fibrate
- HTN: Monitor potassium, creatinine if using ACE inhibitor, ARB agent, or diuretic.
- DM: Check hemoglobin A1C, urine microalbumin, and yearly eye exam
Diet
Nutrition counseling is indicated in patients with suboptimal dietary habits.
Patient Education
Patient-centered action plan to help patients change lifestyle behaviors and use prescribed medication
Prognosis
Long-term risk of future CHD events can be estimated by various models, including the Framingham Risk Equation (see "Additional Reading"¯ section)
Complications
- Side effects can occur with all drug therapies.
- Rhabdomyolysis is a rare, life-threatening potential side effect of statin therapy, occurring in <1% of cases.
Additional Reading
1
33rd Bethesda Conference. J Am Coll Cardiol. 2002;21;40(4). 2
Caraballo RS, Yee SL, Gfroerer JC
Tobacco use among racial and ethnic population subgroups of adolescents in the United States. Prev Chronic Dis. 2006;3:A39. [View Abstract] 3
Cardiovascular risk factors in youth with implications for aging: The Bogalusa Heart Study. Neurobiol Aging. 2005;26(3):303-307. 4
Centers for Disease Control and Prevention. Incidence of initiation of cigarette smoking-United States, 1965-1996. MMWR Morb Mortal Wkly Rep. 1998;47:837-840. 5
Chobanian AV, Bakris GL, Black HR. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. JAMA. 2003;289:2560-2572. [View Abstract] 6
Forman JP, Rim EB, Curhan GC.
Frequency of analgesic use and risk of hypertension among men. Arch Intern Med. 2007;167(4):394-399. [View Abstract] 7
Framingham Risk Calculator: hp2010.nhlbihin.net/atpiii/calculator.asp 8
Grundy SM, Cleeman JI, Merz CN. Implications of recent clinical trials for the National Cholesterol Education Program Adult Treatment Panel III Guidelines. Circulation. 2004;110:227-239. [View Abstract] 9
Hopkins PN, Williams RR.
A survey of 246 suggested coronary risk factors. Atherosclerosis. 1981;40(1):1-52. [View Abstract] 10
Kuller LH.
Prevention of cardiovascular disease and the future of cardiovascular disease epidemiology. Int J Epidemiol. 2001;30(suppl):S66-S72. [View Abstract] 11
Kullo IJ, Ballantyne CM.
Conditional risk factors for artherosclerosis. May Clin Proc. 2005;80(2):219-230. [View Abstract] 12
Nemetz PN, Roger VL, Ransom JE. Recent trends in teh prevalence of coronary disease: A population-based autopsy study of nonnatural deaths. Arch Intern Med. 2008;168(3):264-270. [View Abstract] 13
Ong KL, Cheung BMY, Bun Man YB. Prevalence, awareness, treatment, and control of hypertension among United States adults 1999-2004. Hypertension. 2007;49:69-75. [View Abstract] 14
State-specific incidence of diabetes among adults-participating states, 1995-1997 and 2005-2007. MMWR. 2008;57:1169-1173.
Patient Teaching
Activity
Physical activity counseling is indicated in patients with suboptimal physical activity habits.
Prevention
Self-management training is essential since CAD prevention efforts are dependent upon individual choices.
Codes
ICD9
414.00 Coronary atherosclerosis of unspecified type of vessel, native or graft
SNOMED
- 53741008 coronary arteriosclerosis (disorder)
- 315016007 at risk of coronary heart disease (finding)
Clinical Pearls
- All adults should be screened for CHD risk factors, including DLP, HTN, and DM.
- Lifestyle therapies are very effective in preventing and treating CHD risk factors.
- Drug therapies, when necessary, are also very effective in treating CHD risk factors.