Chronic Stable Angina - Therapeutics Overview

Chronic Stable Angina - Therapeutics

• Chronic stable angina is a condition with overlapping terms, describing ischemic heart disease (IHD), a form of chronic coronary disease (CCD).
• Learning objectives include defining CCD and IHD types, relating pathophysiology to therapy, understanding clinical presentation, identifying risk factors, recalling angina classification/treatment goals, recommending non-pharmacological and pharmacological therapy for chronic stable angina, describing medication therapy details for chronic stable angina; and creating a patient care plan.
• Required resources include a pharmacotherapy textbook chapter on stable ischemic heart disease, a guideline for the management of patients with chronic coronary disease, and a drug information handbook.
• Top 200 Medications knowledge is needed. Knowledge of mechanism of action, pharmacokinetic/dynamic properties (e.g., t1/2, ADME), adverse reactions, monitoring parameters, contradictions, black box warnings, major drug interactions, available dosage formulations, and clinical pearls are required. Specific medications included in this topic are aspirin, clopidogrel, metoprolol succinate, amlodipine, diltiazem, nitroglycerin, isosorbide mononitrate.

Study Guide Questions

• Chronic coronary disease (CCD) is a heterogeneous group of conditions including obstructive and non-obstructive coronary artery disease (CAD), with or without prior myocardial infarction (MI) or revascularization, chronic angina syndrome with varying underlying causes.
• Ischemic heart disease (IHD) involves reduced oxygenated blood supply to the heart due to stenosis in major coronary arteries. This imbalance between myocardial oxygen supply and demand causes angina.
• Common clinical manifestations of IHD include chronic stable angina, unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI).
• The most common symptom of IHD is angina pectoris (chest pain).

Risk Factors for IHD

• Modifiable risk factors include smoking, dyslipidemia, elevated LDL/total cholesterol, reduced HDL cholesterol, diabetes mellitus, hypertension, physical inactivity, low fruit and vegetable consumption, and obesity.
• Nonmodifiable risk factors include age (≥45 for men, ≥55 for women). Family history of premature cardiovascular disease in first-degree relatives (<55 for men, <65 for women) is also a risk factor.

Stable vs. Acute Coronary Syndrome (ACS)

• Stable IHD is characterized by established atherosclerotic plaques impeding blood flow. Myocardial oxygen demand exceeds supply, resulting in chronic stable angina.
• Hallmark features of ACS include rupture and subsequent thrombus of atherosclerotic plaques, exposing plaque contents to the bloodstream, leading to a rapid decrease in myocardial perfusion. This triggers acute situations like unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI).

Prinzmetal or Variant Angina

• Variant angina is characterized by coronary artery vasoconstriction or spasm, often occurring at rest or early morning. It is often associated with younger patients and usually does not exhibit classic risk factors for IHD.
• This type of angina differs from chronic stable angina as it arises from coronary spasms.

Angina Classes

• The Canadian Cardiovascular Society (CCS) classification system categorizes angina into four classes (I-IV) based on the degree of disability due to angina. Class I indicates no limitations upon physical activity. Class IV symptoms appear during rest. These classes are helpful for assessing patients with IHD over time and quantifying effects of medication therapy.

Treatment Goals for Stable IHD

• Alleviating acute angina symptoms, preventing recurrent symptoms, preventing IHD progression, reducing the risk of IHD complications, and minimizing adverse treatment effects.

PCI or CABG Indications

• Optimal medical therapy is preferred initially for stable IHD. Percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery may be indicated if optimal medical therapy is unsuccessful. This occurs when symptoms become unstable or extensive coronary atherosclerosis is present (e.g., >70% occlusion of the coronary lumen).

Antiplatelet Therapy

• The necessity of dual antiplatelet therapy (DAPT) after PCI is for reducing atherosclerotic events.
• If the patient has a higher bleeding risk after PCI, a lower-dose DAPT or a shorter duration of DAPT might be considered.
• Patients with a history of significant bleeding are candidates for DAPT treatment for a shorter duration.
• Antiplatelet medications like aspirin and clopidogrel are essential in preventing restenosis.

Aspirin and Clopidogrel Dosing

• Aspirin dose is usually 81mg, however doses between 75-100mg may be used.
• Clopidogrel is typically 75mg daily and used in conjunction with aspirin; the duration of this dual therapy is generally 12 months but may be extended/shortened depending on certain patient characteristics.
• Dual antiplatelet therapy (DAPT) is often recommended for a period after stenting to prevent in-stent thrombosis.

Nitrates

• Short-acting nitrates (e.g., sublingual nitroglycerin) are given to relieve acute angina symptoms.
• Long-acting nitrates are used for long-term angina prevention.
• Patients using nitrates should be aware that they may cause hypotension, dizziness, or light-headedness, particularly if they stand up after administration. The drug can interact with other medications and precautions must be considered.

Beta-Blockers

• Beta-blockers are first-line therapies for long-term angina prevention.
• Beta-blockers with intrinsic sympathomimetic activity should be avoided for IHD management. They do not lower heart rate effectively.

Calcium Channel Blockers

• Nondihydropyridine CCBs (e.g., verapamil, diltiazem) and dihydropyridine CCBs (e.g., amlodipine, nifedipine) are often used for chronic stable angina as they reduce the heart rate and myocardial oxygen demand; dihydropyridines are preferred over nondihydropyridines if used with beta-blockers.
• CCBs should be used with caution in combination with beta-blockers due to the potential for bradycardia/AV block.

Ranolazine

• Ranolazine is an alternative treatment for chronic stable angina, especially in those who do not respond well or experience side effects with beta-blockers or calcium channel blockers.