L 14 Coronary Heart Disease Study Notes

Coronary Heart Disease

Definition, Epidemiology, and Risk Factors

  • Definition: Coronary Heart Disease (CHD), also known as Coronary Artery Disease (CAD), is characterized by the narrowing or blockage of coronary arteries due to atherosclerosis.

  • Epidemiology:

    • Leading cause of death for both men and women in the United States.

    • 1 in 4 deaths in the US is due to CHD.

    • One person dies every minute from CHD in the US.

    • CHD is the number one cause of death worldwide.

    • Death rates from CHD have declined yearly since 1968 due to risk factor modifications and improvements in medical/surgical therapies.

    • However, aging of the US population will likely lead to increased prevalence of CHD despite preventive measures.

  • Risk Factors:

    • Family History: Premature CHD (myocardial infarction or death from CHD in a first-degree relative before age 55 in males or 65 in females).

    • Cigarette Smoking.

    • Dyslipidemia.

    • Hypertension.

    • Age: Male ≥ 45, Female ≥ 55.

    • Gender: Males generally present higher risk; risk increases for females post-menopause.

    • Inflammation: Elevated high-sensitivity C-reactive protein (hs-CRP): Low risk <1, Intermediate risk 1-3, High risk >3.

    • Chronic Conditions: Diabetes mellitus, chronic kidney disease.

    • Lifestyle Factors: Obesity, poor diet, lack of physical exercise.

    • Psychosocial Factors: Stress, depression, HIV, mediastinal radiation, microalbuminuria.

Course Content Overview

  • Focus of the course includes:

    • Coronary heart disease/CAD

    • Stable angina pectoris

    • Acute coronary syndrome (ACS): unstable angina, NSTEMI, STEMI

    • Vasospastic angina

    • Sudden cardiac death (SCD)/Sudden cardiac arrest (SCA)

Learning Objectives

  • Recognize risk factors and identify high-risk patients for CHD, stable angina pectoris, ACS, vasospastic angina, and SCD/SCA.

  • Describe clinical presentations associated with each condition, including symptoms and physical exam findings.

  • Conduct a focused medical history and targeted physical examination for patients presenting with CHD and related conditions.

  • Use and interpret the ACC ASCVD and AHA PREVENT risk calculators.

  • Select and interpret laboratory and diagnostic tests related to diagnosis and management of these conditions.

  • Apply diagnostic criteria and create management plans for patients.

  • Understand pharmacologic and nonpharmacologic treatments, including indications, side effects, complications, and contraindications.

  • Outline methods for primary and secondary prevention of CHD.

  • Apply screening recommendations for CHD.

Pathophysiology

  • Atherosclerosis: Characteristics include:

    • Initiated by endothelial injury/dysfunction, leading to smooth muscle cell proliferation, inflammatory cell recruitment, and lipid deposition.

    • Fatty streaks in childhood evolve into atherosclerotic plaques, which narrow the coronary artery lumen, affecting myocardial blood flow.

  • Plaque rupture exposes a thrombogenic core, leading to platelet adherence, aggregation, and potential acute coronary syndromes (ACS).

Mathematical Display:

  • Coronary Artery Lumen Stenosis:

    • Low ESS (Endothelial Shear Stress) correlates with

    1. No lumen stenosis: No remodeling, inflammation +, early plaque formation.

    2. Lumen stenosis <30%: Expansive remodeling, inflammation ++, small lipid pool, non-stenotic.

    3. Lumen stenosis <50%: Expansive remodeling, inflammation +++, large lipid pool, thin fibrous cap.

    4. Lumen stenosis >50%: Expansive remodeling, inflammation +++, large lipid pool, thin fibrous cap, plaque rupture leading to acute coronary event.

High-Risk Patients

  • Risk for major coronary events similar to established CHD patients includes those with:

    • Noncoronary atherosclerotic diseases (e.g. carotid artery disease, peripheral artery disease, abdominal aortic aneurysm).

    • Diabetes mellitus and chronic kidney disease.

Symptoms of CHD

  • Symptoms can be:

    • Asymptomatic

    • Chest pain or angina: Heaviness, pressure, squeezing, burning.

    • Pain radiating to the arm, shoulder, neck, or jaw.

    • Dyspnea, syncope, weakness, fatigue, palpitations, and signs of heart failure.

Diagnostic Testing

  • Testing and imaging modalities include:

    • Laboratory tests: No single test confirms CHD; typical tests include lipid panels, complete metabolic panels, troponin (when ACS suspected).

    • ECG: Low sensitivity for diagnosing CHD; changes during angina may show ST depression. Assessed abnormalities increase CHD risk.

    • Imaging: Echocardiogram to evaluate cardiac function and identify wall motion abnormalities.

    • Coronary Angiography: Considered the gold standard; assesses degree and location of stenosis and complications (risk <1% for serious adverse outcomes).

Management Strategies

  • Medical Therapies:

    • Antiplatelet agents (Aspirin, P2Y12 receptor blockers).

    • Statins for LDL reduction and atherosclerosis regression.

    • Beta blockers for reducing anginal episodes and improving exercise tolerance.

    • Calcium channel blockers and nitrates to manage symptoms.

    • ACE inhibitors and ARBs for patients with hypertension or heart failure.

    • Ranolazine for chronic angina.

  • Interventional Treatments:

    • Percutaneous Coronary Intervention (PCI) with stenting, preferred for stenosis ≥70%.

    • Coronary Artery Bypass Grafting (CABG) recommended for patients with multiple lesions or complex anatomy.

Screening Recommendations

  • Begin screening at age 20:

    • Baseline lipid panel and ASCVD risk calculation.

    • General consensus suggests no routine screening in asymptomatic patients; individual risk assessments should be factored in.

Conclusion

  • Emphasize lifestyle modifications and ongoing management for patients with CHD for secondary prevention and improving outcomes.