Myocardial Perfusion Imaging and Coronary Angiography Quiz

Angina Pectoris Overview

• Typical duration of angina ranges from a few minutes to 15-20 minutes.
• Heberden described discomfort in angina pectoris as a "sensation of pressure, fullness, or tightness in the chest."
• Common symptoms in the elderly with angina include fatigue, dyspnea, and atypical pain presentations.

Precipitation and Relief of Angina

• Angina is typically precipitated by physical exertion, emotional stress, or heavy meals.
• Relief of angina usually occurs with rest or the use of nitroglycerin within minutes.
• Severe ongoing ischemia indicates a possibility of myocardial infarction if angina pain is not relieved within 5-10 minutes.

Causes and Risk Factors

• The most common cause of myocardial ischemia is coronary artery disease (CAD).
• Myocardial wall stress is determined by factors including left ventricular pressure and chamber dimensions.

Classification and Dysfunction

• In the Canadian Cardiovascular Society Classification, angina occurs with "slight limitations of ordinary activity" at Class II.
• Transient left ventricular (LV) and papillary muscle dysfunction can result from ischemia.

Cardiovascular Risk

• The presence of coronary artery disease (CAD) is a strong predictor of morbidity and mortality.
• Abnormal ECG may occur in approximately 50% of patients with normal baseline ECG during stress testing.

Diagnostic Tools

• The primary purpose of 24-hour Holter monitoring is to assess heart rhythms in patients with suspected arrhythmias.
• Echocardiography provides vital information about cardiac structure and function in patients with chronic coronary syndrome (CCS).
• Stress testing should not be used in patients with unstable angina or severe aortic stenosis.

Imaging and Perfusion

• Myocardial perfusion imaging assesses blood flow to heart muscles under stress and resting conditions.
• Magnetic resonance imaging (MRI) is employed to evaluate suspected coronary artery disease (CAD) by visualizing heart structures.

Biochemical Markers and Antithrombotic Therapy

• Biochemical tests for dyslipidemias typically include total cholesterol, low-density lipoprotein (LDL), and triglycerides.
• In specific high-risk situations, clopidogrel may be considered as an antithrombotic after stenting.
• For patients with aspirin intolerance, clopidogrel is the recommended alternative antithrombotic drug.

Variant Angina Management

• The mainstay medical therapy for variant (Prinzmetal’s) angina, in the absence of significant atherosclerosis, includes calcium channel blockers.
• Clopidogrel is recommended for a duration of at least 12 months following coronary stenting.
• Statin treatment should be considered for all patients with established CAD, regardless of LDL-C levels.

Ischemia and Prevention

• Episodes of myocardial ischemia in Variant Angina Pectoris are responsible for transient vasospasm.
• Vasospastic angina development is often associated with stress and exposure to cold.
• In treating Variant Angina Pectoris, avoiding beta-adrenergic agonists is crucial.

Long-term Management Strategies

• Patients at high risk of ischemic events but without high bleeding risk should have long-term secondary prevention measures.
• Post-stenting, dual antithrombotic therapy including aspirin and clopidogrel is standard practice.
• For patients with stable angina and coexisting conditions like hypertension or heart failure, evaluation for revascularization might be necessary.

Recommendations Against Treatment

• Certain treatments, such as routine use of antiarrhythmics or antianginal medications without clear indications, are not recommended in chronic CAD management.

Diagnostic Testing

• High-risk patients with stable angina should undergo non-invasive imaging stress tests for better risk stratification.
• Nitrates primarily dilate coronary blood vessels, improving blood supply to the heart muscle.

Medication Use

• A 10 to 12-hour nitrate-free interval is necessary to prevent tolerance to nitrates.
• Beta-blockers function to enhance myocardial oxygen supply while reducing demand, effectively managing angina.
• ACE inhibitors benefit patients with CAD by reducing afterload and improving cardiovascular outcomes.

Emergency Responses

• Nitroglycerin is the first-line medication for immediate relief of angina symptoms.
• Low-dose aspirin works by inhibiting platelet aggregation, reducing the risk of myocardial infarction and stroke.

Special Considerations

• Abrupt withdrawal of beta-blockers can precipitate unstable angina due to rebound tachycardia and increased myocardial oxygen demand.
• Isosorbide 5-Mononitrate should be given once daily to maintain stable therapeutic levels without leading to tolerance.
• Non-invasive anatomical evaluations can be performed using computed tomography (CT) or coronary angiography to visualize coronary arteries.

Test your knowledge of myocardial perfusion imaging and coronary angiography, including indications for coronary angiography and anatomical non-invasive evaluation.