What is the significance of Acute Coronary Syndrome (ACS) in the setting of a recent illness?

From the Guidelines

Patients with recent illnesses who develop symptoms of acute coronary syndrome (ACS) should seek immediate medical attention, as the presence of ACS in this setting is strongly associated with higher mortality and more frequent readmissions, especially for heart failure 1. In the setting of recent illness, ACS can be triggered by increased inflammatory responses and metabolic demands. The connection between illness and ACS stems from inflammation-induced plaque instability, increased oxygen demand from fever and tachycardia, dehydration causing blood viscosity changes, and stress-induced catecholamine surges. Some key points to consider in managing ACS in the setting of recent illness include:

• Patients at highest risk for acute decompensated heart failure in the setting of ACS are older, female, and have preexisting heart disease, type 2 diabetes mellitus, hypertension, and/or kidney disease 1.
• Standard ACS management includes aspirin, antiplatelet therapy, anticoagulation, and other medications based on presentation.
• Respiratory infections particularly increase ACS risk through hypoxemia and direct inflammatory effects on coronary vessels.
• Patients with known coronary artery disease should be especially vigilant about cardiac symptoms during or shortly after illnesses and maintain hydration, continue prescribed cardiac medications, and manage fever appropriately during illness to reduce ACS risk.
• Improved utilization of current therapies, coupled with further investigation of strategies to manage ACS-HF, is desperately needed to improve outcomes in this vulnerable population 1.

From the FDA Drug Label

The CURE study included 12,562 patients with ACS without ST-elevation (UA or NSTEMI) and presenting within 24 hours of onset of the most recent episode of chest pain or symptoms consistent with ischemia Patients were required to have either ECG changes compatible with new ischemia (without ST-elevation) or elevated cardiac enzymes or troponin I or T to at least twice the upper limit of normal. The number of patients experiencing the primary outcome (CV death, MI, or stroke) was 582 (9.3%) in the clopidogrel-treated group and 719 (11.4%) in the placebo-treated group, a 20% relative risk reduction (95% CI of 10% to 28%; p <0. 001) for the clopidogrel-treated group

Clopidogrel is indicated to reduce the rate of myocardial infarction (MI) and stroke in patients with non–ST-segment elevation ACS (unstable angina [UA]/non–ST-elevation myocardial infarction [NSTEMI]).

• Key benefits of clopidogrel in the setting of recent illness include:
  • Reduction in the rate of myocardial infarction and stroke
  • Decrease in the use of thrombolytic therapy and GPIIb/IIIa inhibitors
• Important considerations:
  • Clopidogrel should be administered in conjunction with aspirin
  • The use of oral anticoagulants, nonstudy antiplatelet drugs, and chronic NSAIDs is not allowed
  • Patients who are homozygous for nonfunctional alleles of the CYP2C19 gene (CYP2C19 poor metabolizers) may have diminished antiplatelet activity 2 2 2

From the Research

Acute Coronary Syndrome (ACS) in the Setting of Recent Illness

• ACS is a major cause of morbidity and mortality, with an annual incidence of approximately 1 million in the United States 3.
• The diagnosis of ACS begins with a thorough clinical assessment of a patient's presenting symptoms, electrocardiogram, and cardiac troponin levels as well as a review of past medical history 4.
• Common risk factors for ACS include being at least 65 years of age or a current smoker or having hypertension, diabetes mellitus, hyperlipidemia, a body mass index greater than 25 kg per m2, or a family history of premature coronary artery disease 5.
• Symptoms most predictive of ACS include chest discomfort that is substernal or spreading to the arms or jaw 5.

Management of ACS

• Dual antiplatelet therapy (DAPT), consisting of aspirin and a P2Y12 inhibitor, reduces cardiovascular event rates after ACS 3.
• Coronary angiography with percutaneous or surgical revascularization is recommended for patients with ACS 5.
• Other important management considerations include initiation of parenteral anticoagulation, statin therapy, beta-blocker therapy, and sodium-glucose cotransporter-2 inhibitor therapy 5.
• Anticoagulation during and after ACS comprises antiplatelet and anticoagulant therapy, with dual antiplatelet therapy composed of aspirin plus a third generation P2Y12 inhibitor (prasugrel or ticagrelor) representing the gold standard 6.

Treatment Considerations

• The American College of Cardiology/American Heart Association (ACC/AHA) recommends aspirin plus a P2Y12 inhibitor for at least 12 months for patients with ACS 3.
• Recommendations for DAPT vary according to the risk of bleeding, with prolonged DAPT considered for patients with low bleeding risk and shorter duration (3-6 months) considered for patients with high bleeding risk 3.
• High-risk patients with NSTE-ACS and no contraindications should undergo prompt invasive coronary angiography and percutaneous or surgical revascularization within 24 to 48 hours 7.