Internal Medicine: Cardiovascular and Pulmonology Review

Coronary Artery Disease (CAD)

  • Leading Cause of Mortality: Atherosclerosis is the primary cause.
  • Ischemic Heart Disease Spectrum: Ranges from asymptomatic CAD to Myocardial Infarction (MI) with ST elevation (STEMI).
  • Acute Coronary Syndrome (ACS): Represents a spectrum of conditions including unstable angina (UA), non-ST elevation MI (NSTEMI), and ST-elevation MI (STEMI). These are acute manifestations of CAD.
Risk Factors
  • Non-modifiable:
    • Age: Women >65 years old, men >55 years old.
    • Family History: Premature CAD (first-degree male relative <55 yo, first-degree female relative <65 yo).
    • Sex: Males generally at higher risk before age 6565.
  • Modifiable:
    • Smoking: Potent risk factor.
    • Hypertension (HTN): Blood pressure (BP) >130/80 mmHg or on antihypertensive medication.
    • Dyslipidemia:
    • High LDL cholesterol (> ext{desired levels}, target is patient-dependent).
    • Low HDL cholesterol (<40 mg/dL).
    • High Triglycerides (> ext{desired levels}).
    • Diabetes Mellitus (DM): A "CAD equivalent."
    • Obesity: Body Mass Index (BMI) >30 kg/m2kg/m^2.
    • Sedentary Lifestyle.
    • Metabolic Syndrome.
Prevention
  • Primary Prevention (Risk Factor Reduction): Focuses on preventing the onset of CAD.
    • Lifestyle Modifications:
    • Smoking cessation.
    • Regular physical activity (e.g., 3030 minutes of moderate-intensity activity most days of the week).
    • Heart-healthy diet (e.g., Mediterranean, DASH diet - low in saturated/trans fats, high in fruits, vegetables, whole grains).
    • Weight management to achieve/maintain a healthy BMI.
    • Medical Management of Risk Factors:
    • Blood Pressure Control: Goal typically <130/80 mmHg for most adults.
    • Lipid Management: Statin therapy based on ASCVD risk assessment (e.g., for LDL >190 mg/dL, patients with DM, or ASCVDASCVD risk >7.5% and other risk factors).
    • Diabetes Management: Glycemic control (e.g., HbA1c <7% for most).
    • Antiplatelet Therapy: Low-dose aspirin for select high-risk patients (e.g., certain DM patients with increased bleeding risk).
Clinical Presentation
  • Stable Angina: Chest discomfort that is predictable, reproducible, and occurs with exertion or stress, relieved by rest or nitroglycerin within minutes.
  • Unstable Angina (UA): Chest discomfort that is new onset, increasing in frequency/intensity, or occurring at rest. Not relieved by rest or nitroglycerin as readily.
  • Myocardial Infarction (MI): Prolonged chest pain, often severe, not relieved by rest or nitroglycerin. Associated symptoms include dyspnea, nausea, diaphoresis. Can be "silent" in diabetics or elderly.
Diagnosis
  • Electrocardiogram (ECG):
    • STEMI: ST-segment elevation in 22 or more contiguous leads; new LBBB.
    • NSTEMI/UA: ST-segment depression, T-wave inversion/flattening, or non-specific changes.
  • Cardiac Biomarkers (Troponins): Elevated in MI (NSTEMI, STEMI), typically rising within 3−123-12 hours, peaking at 24−4824-48 hours, and remaining elevated for 5−105-10 days.
  • Stress Testing: (Pharmacological or exercise) Used to evaluate for inducible ischemia in stable CAD or after ACS stabilization.
    • Exercise Stress Test (ETT)
    • Pharmacological Stress Test (adenosine, dobutamine) with imaging (echocardiography or nuclear).
  • Coronary Angiography: Definitive diagnosis and assessment of CAD severity, guiding revascularization decisions.
Management
  • Lifestyle Modifications: (As described in Prevention).
  • Medical Therapy:
    • Antiplatelets:
    • Aspirin: Irreversible COX-1 inhibitor, generally 8181 mg daily for secondary prevention.
    • P2Y12 Receptor Blockers: Clopidogrel, Ticagrelor, Prasugrel (used often with aspirin for Dual Antiplatelet Therapy (DAPT) post-ACS or PCI).
    • Beta-blockers: Reduce myocardial oxygen demand; improve survival post-MI.
    • ACE Inhibitors/ARBs: Especially for patients with hypertension, DM, heart failure, or post-MI with LV dysfunction.
    • Statins: High-intensity statins for most with CAD to aggressively lower LDL.
    • Nitrates: For symptomatic relief of angina (sublingual, oral, transdermal).
  • Revascularization:
    • Percutaneous Coronary Intervention (PCI): Angioplasty with stent placement for significant stenoses.
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