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Coronary Disease

Basics

Description

- 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)

- Coronary MRI: - Evaluates: Coronary stenoses, coronary flow, myocardial perfusion, and wall motion abnormalities - Particularly helpful in women with suspected impaired microvascular dysfunction

  • 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 stenosesWomen have symptoms despite less obstructionOther factors decrease flow in women > men
  • Different mechanisms for IHD in symptomatic womenSymptoms 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 womenRisk elevated even with minimal use (1-4 cigs/day)
  • Elevated cholesterol:Low HDL more important than high LDLBest 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 IHDIncreased 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 usedIncorporates age, gender, and traditional RF to estimate risk of developing coronary heart disease (CHD) within 10 yearsValidated 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 womenChest 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 abnormalitiesParticularly 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:
  • Increased risk due to:Hypercoagulable stateIncreased myocardial oxygen demand
  • Risk factors:Age >33 yearsMultigravida
  • 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 >55Not 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 abovePrimary 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.