Review Question - QID 103357

This patient with known coronary artery disease (CAD) presents with angina at rest, thus the diagnosis is unstable angina, a variant of acute coronary syndrome (ACS). All of the above are strong indications for intervention except answer 2, positive cardiac biomarker, which alone is not enough to warrant this management.

Patients with ACS are categorized into unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI). Within the diagnoses of UA and NSTEMI, patients are risk-stratified according to the patient's clinical status, with management based on this stratification. Patients with high-risk features are typically managed with percutaneous coronary intervention (PCI), while stable patients without any of these features can be managed conservatively. High-risk features generally include: hemodynamic instability, severe left ventricular dysfunction, recurrent or persistent angina at rest despite therapy, new/worsening mitral regurgitation or VSD, sustained ventricular arrhythmias.

Wiviott and Braunwald review the initial evaluation and management of patients with UA and NSTEMI. They mention standard medical therapies for these patients, which include unfractionated heparin, aspirin, P2Y12 ADP-blocking agents such as prasugrel or clopidogrel, and for some patients, a glycoprotein IIb/IIIa inhibitor such as eptifibatide (Integrelin). Importantly, this last class of medications is typically indicated only for patients who will likely undergo PCI. Rather than examining specific clinical factors individually, a more quantitative risk stratification can be derived with the TIMI risk score, which estimates short-term mortality in patients presenting with UA/NSTEMI based on clinical characteristics.

The question of which P2Y12 ADP-blocking agent is chosen was addressed by Roe et al. in the TRILOGY ACS trial, which randomized 7243 patients with UA/NSTEMI not undergoing PCI to clopidogrel or prasugrel. Notably, they found no difference in the primary outcome (composite of death from cardiovascular causes, nonfatal MI, or nonfatal stroke) between the two medications. There was a trend towards increased bleeding in patients treated with prasugrel, although it did not reach statistical significance.

Figure A shows an ECG in a patient with known CAD who presented with UA, as was the case with this patient. There are signs of prior myocardial damage, including pathological Q waves and a right bundle branch block. Importantly, no acute ST-segment changes are seen.

Incorrect answers:
Answers 1, 3-5: These are all strong indications for early PCI in patients with UA/NSTEMI.