Coronary Artery Disease - STEMI Case #10 Answer

A 78-year-old female with a history of hypertension, type 2 diabetes and dyslipidemia presents with severe indigestion. She is diaphoretic and dizzy. Her temperature is 98.8, blood pressure 150/90 mm Hg, heart rate 90 beats per minute, respirations 26 per minute. Chest X-ray reveals mild pulmonary edema. Her ECG is below:

LeftMain-Ischemia-WM

Emergent cardiac catheterization is performed. She is found to have a 90% distal left main stenosis but only mild disease in her circumflex, left anterior descending and right coronary artery. Her rhythm then changes to the below:

MonomorphicVTach

Emergent cardioversion is successful, and she is treated with intravenous amiodarone therapy as well as standard medical therapy for an acute coronary syndrome. Which of the following is the next best course of action?

A. Emergency coronary artery bypass grafting

B. Primary percutaneous coronary intervention (PCI) of the left main coronary artery

C. Fibrinolytic therapy

D. Medical management alone

 

The patient’s ECG tracing and coronary angiogram are consistent with severe left main coronary artery stenosis. Coronary artery bypass grafting, or CABG, as a means of coronary revascularization is indicated in the following situations:

  1. PCI fails, and there are persistent symptoms or hemodynamic instability
  2. A patient is not a candidate for PCI and has continued symptoms with a significant area of myocardium at risk
  3. At the time of ventricular septal defect or mitral valve repair
  4. When left main coronary disease or three-vessel coronary disease is present with cardiogenic shock or ventricular arrhythmias (ventricular tachycardia or fibrillation)

CABG is not indicated when there is a small area of myocardium in jeopardy and the patient is stable, or in three-vessel coronary disease in a stable patient experiencing a STEMI.

Treating the left main with PCI is dangerous, as any complication (coronary dissection or rupture) could be fatal in this scenario. Also, acute stent thrombosis, if it occurs, would result in a large myocardial infarction and would likely be fatal. Therefore, PCI of the left main coronary artery is indicated at this time only if the patient is not a surgical candidate for CABG, or if the patient previously had a left internal mammary coronary artery, or LIMA, grated to the left anterior descending, causing a “protected left main” scenario. In this case, even if the left main coronary artery occluded, there would still be antegrade flow to the left anterior descending through the LIMA graft.