Coronary Disease

Basics

Description

Ischemic heart disease (IHD) has been defined by the presence of atherosclerosis in the epicardial coronary arteries.
Atherosclerosis forms plaque in coronary vessels, progressively impairing myocardial blood flow.
Women have smaller coronary vessels.
- Plaque in women distributed diffusely with less areas of critical stenoses
- Women have symptoms despite less obstruction
- Other factors decrease flow in women > men
Different mechanisms for IHD in symptomatic women
- Symptoms and signs of IHD in women may be due to significant obstruction (>50% obstruction in one or more vessels) alone or in combination with other recently identified mechanisms for impaired vascular flow.
Persistent symptoms and signs of IHD in women without evidence of obstructive disease suggest the dominance of these other mechanisms in impaired vascular flow (see "Pathophysiology").

Epidemiology

Women develop IHD 10-15 years later than men; at lower IHD risk until the seventh decade.
Women with new onset IHD more likely to present with angina, followed by myocardial infarction (MI) (usually nontransmural).
Less likely to have sudden death although increased rates in last 10 years
Women are more likely to have silent MI.
Women have a higher prevalence of congestive heart failure.

Incidence

The lifetime risk of IHD for women aged 40 is 32% (49% in men of same age).
Even women free from disease at age 70 have a lifetime risk of 24% (35% in men).
250,000 IHD deaths/year in women
38% women vs. 22% men will die in the year post-hospitalization for MI.
IHD responsible for 38% of all deaths in women vs. 22% deaths from cancer.

Risk Factors

Individual risk factors (RF) less predictive of IHD in women; clustering of RF more predictive
Strongest predictors in women: Diabetes and low HDL cholesterol

Strongest risk/well established

Diabetes (considered equivalent to having known IHD):
- Stronger predictor of IHD risk and prognosis in women than men
Smoking:
- Seen in 50% of all acute IHD in women
- Risk elevated even with minimal use (1-4 cigs/day)
Elevated cholesterol:
- Low HDL more important than high LDL
- Best estimate of risk: Total to HDL ratio
Hypertension: Most common RF in women
Family history premature IHD (first-degree male relative <55 or female relative <65)
Peripheral vascular disease
Chronic kidney disease

Moderate risk

Hormones:
- Low endogenous estrogen levels seen in premenopausal women with signs and symptoms of IHD
- Increased risk of IHD postmenopause
Elevated triglycerides: RF for women > men
Obesity
Sedentary lifestyle
Metabolic syndrome: Consists of 3 or more of the following:
- Central obesity (waist >35 inches)
- Glucose intolerance (FBS >110 mg/dL)
- Elevated fasting triglycerides (>150 mg/dL)
- Low-serum HDL (<50 mg/dL)
- Elevated blood pressure (>130/85)

Other risk factors/less data available

Inflammatory markers: CRP, WBC, amyloid A
Hemostatic labs: Fibrinogen, Factor V Leiden
Homocysteine
Microalbuminuria
Psychosocial (stress, depression, anxiety)

Assessing pretest risk

Framingham risk score (FRS): Most used
- Incorporates age, gender, and traditional RF to estimate risk of developing coronary heart disease (CHD) within 10 years
- Validated and works well in black and white women (and men)
Reynolds risk score: Developed on women with different variables (including hsCRP), adds discrimination to 40-50% of women with FRS intermediate score

Pathophysiology

Multiple gender differences contribute to the pathogenesis of IHD with women having:

Smaller arterial size
Increased inflammatory and immunologic factors
Less focal and more diffuse distribution of atheroma
Increased vascular stiffness
Differences in hormone levels
Endothelial dysfunction with decreased flow-mediated dilation
Microvascular dysfunction

Diagnosis

History

Women delay presentation despite having symptoms of longer duration than men.
Signs and symptoms: Differ in women
- Chest pain may occur with or without exertion, in stressful situations, and may even awaken someone from sleep.
- Chest pain may be absent: May have pain in neck, jaw, or back only.
- Shortness of breath is common.
- Atypical symptoms more likely: Dizziness, weakness, fatigue

Physical Exam

Vital signs:
- BP and heart rate are variable and may be normal.
Cardiovascular exam: Assess for murmurs, extra heart sounds, point of maximum impulse (PMI)
Lung exam: Listen for crackles
Abdominal exam: Listen for bruits
Peripheral vascular exam: Assess for peripheral vascular disease

Tests

Lab

BUN, creatinine, electrolytes, fasting glucose, fasting lipid panel, CBC
Troponin and MB-CPK in the acute setting
CRP and homocysteine
Urine microalbumin

Surgery

EKG:
- Women have more baseline EKG changes due to heart size, axis, fluctuating hormone levels making diagnosis of acute IHD more difficult.
Noninvasive testing:
- Duke Activity Status Index (DASI asks ability to perform 12 activities of daily living with MET score for each) to assess pretest exercise tolerance (1)[A].
- Knowledge of women's functional capacity determines appropriate cardiac testing.
- Consider pharmacologic stressors for women with low score on DASI/inability to exercise.
- Test characteristics vary by gender:
  - Exercise stress test: Sensitivity 61%; specificity 70%
  - Stress SPECT test: Sensitivity 78%; specificity 64%
  - Stress echocardiogram: Sensitivity 86%; specificity 79%
- Coronary CT:
  - Measures coronary calcification: Increased amount is associated with increased cardiac mortality in women.
  - May be useful for women with abnormal EKG, symptoms and risk factors for CHD, and/or intermediate risk stress test.
- Coronary MRI:
  - Evaluates: Coronary stenoses, coronary flow, myocardial perfusion, and wall motion abnormalities
  - Particularly helpful in women with suspected impaired microvascular dysfunction
Cardiac catheterization (CC):
- Women are more likely to have single vessel disease.
- Patients with nonobstructive disease (<50% stenosis) may have ongoing ischemia in the setting of vascular dysfunction.

Acute MI 1/10,000 pregnancies:
- Most in third trimester
Increased risk due to:
- Hypercoagulable state
- Increased myocardial oxygen demand
Risk factors:
- Age >33 years
- Multigravida
Causes:
- Atherosclerosis with or without thrombosis: 43%
- Coronary thrombosis without atherosclerosis: 21%
- Coronary dissection: 16%
- Coronary aneurysm: 4%

Differential Diagnosis

Differential diagnosis for chest pain in women varies by age

Young women: Costochondritis and GI causes predominate (gastroesophageal reflux disease, gastritis, irritable bowel syndrome)
Middle-aged women: Menopause, GI causes predominate
Older women: Aortic dissection, pulmonary (pulmonary embolism, pneumonia, cancer). May also include costochondritis and GI causes

Treatment

Medication

Equal efficacy of medication for females as males (including beta blockers, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers) in post-MI patients or patients with active IHD (2)[A-B]
Hormone therapy - no benefit and possible harm (2)[A]
Aspirin:
- Effective as a secondary prevention of IHD events and stroke (2)[A]
- May be indicated as primary prevention in high-risk women and those >55
- Not shown to be effective as primary prevention in low-risk women <55

Additional Treatment

General Measures

Initial care for acute coronary event (ACE)
- Identify ACE and hospitalize for additional evaluation and stabilization (not further addressed in this chapter)
- Identify the extent of CHD and the appropriate long-term treatment:
  - Women with an abnormal catheterization are equally likely as men to be referred for revascularization.
  - Women with no or nonobstructive atherosclerosis and persistent symptoms/signs could have vascular dysfunction and need additional studies/referral to a cardiologist.
- Address cardiovascular risk reduction (see below).

Issues for Referral
Referral to a cardiologist:

Post-hospitalization for ACE for additional testing, medication adjustment, referral for cardiac rehabilitation.
Post-CC with nonobstructive disease but persistent symptoms for testing for vascular dysfunction.

Additional Therapies
Goal: To reduce cardiovascular risk in women with recent ACE or at high risk for IHD

Smoking cessation: Associated with rapid reduction in risk of MI (3)[B]
Control of diabetes: Tight diabetic control reduces microvascular disease and improves other cardiac RF
Control of hypertension: Reduces risk of IHD (2)[A]
Treatment of elevated cholesterol: With diet and medication (2)[B]
Cardiac rehab: Indicated for all women post-ACE (2)[A]
Weight loss: Improves or prevents obesity-related RF for IHD

Ongoing Care

Diet

Indicated for all patients post-ACE or at high risk of CHD
Diet rich in vegetables and fruits, with whole grain, high-fiber foods, fish twice per week, saturated fat in very small amounts (<7% daily energy) and daily cholesterol intake <300 mg (2)[B]

Patient Education

Education about IHD risk reduction should take place in office for women at all levels of risk.
Weight loss for BMI >25 and waist >35 inches (2)[B]
Exercise: 20-40 minutes of brisk exercise most days of week (2)[B]
Cholesterol lowering:
- Dietary therapy: As above
- Primary prevention data support treatment in high-risk women with diabetes or chronic kidney disease or FRS >10% and elevated cholesterol (2)[B]
- Data less clear for medication for <55 women with no risk factors and elevated cholesterol

References

1Shaw LJ, Merz CNB, Pepine CJ. Insights from the NHLBI-sponsored Women's Ischemia Syndrome Evaluation (WISE) study. Part I: Gender differences in traditional and novel risk factor, symptom evaluation and gender optimized diagnostic strategies. J Am Coll Cardiol. 2006;47:S4-S20. [View Abstract]2Mosca L, Benjamin EJ, Berra K Effectiveness-Based Guidelines for the Prevention of Cardiovascular Disease in Women-2011. Update: A Guideline from the American Heart Association. Circ. 2011;123:1243-1262.3Merz CNB, Shaw LJ, Reis SE. Insights from the NHLBI-sponsored Women's Ischemia Syndrome Evaluation (WISE) study. Part II: gender differences in presentation, diagnosis, and outcome with regard to gender-based pathophysiology of atherosclerosis and macrovascular and microvascular coronary disease. J Am Coll Cardiol. 2006;47:S21-S29.

Additional Reading

http://www.americanheart.org
http://www.womenshealth.gov
http://hp2010.nhlbihin.net/atpiii/calculator.asp (Framingham risk score)
www.reynoldsriskscore.org (Reynolds risk score)

Codes

ICD9

413.9 Other and unspecified angina pectoris
414.01 Coronary atherosclerosis of native coronary artery
414.9 Chronic ischemic heart disease, unspecified
410.90 Acute myocardial infarction of unspecified site, episode of care unspecified

ICD10

I20.9 Angina pectoris, unspecified
I25.9 Chronic ischemic heart disease, unspecified
I25.10 Athscl heart disease of native coronary artery w/o ang pctrs
I25.119 Athscl heart disease of native cor art w unsp ang pctrs
I21.3 ST elevation (STEMI) myocardial infarction of unsp site

SNOMED

414545008 ischemic heart disease (disorder)
53741008 coronary arteriosclerosis (disorder)
194828000 angina (disorder)
22298006 myocardial infarction (disorder)

Clinical Pearls

Ischemic heart disease (IHD) is the leading cause of death in women of all ages.
IHD is a disease of older women and more common in certain racial and ethnic minorities (African Americans, Native Americans).
Mechanisms for IHD in women are different, necessitating new technologies for evaluation and potentially new treatment.
Women continue to be under-represented in studies of the evaluation and treatment of IHD.

Home

Erectile Dysfunction

Doctor123.org