Spontaneous Coronary Artery Dissection: Pathophysiological Insights From Optical Coherence Tomography

Area of Science:

• Cardiovascular Imaging
• Interventional Cardiology
• Pathophysiology of Atherosclerosis

Background:

• Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of acute coronary syndromes.
• SCAD is characterized by the formation of a false lumen (FL) that compresses the true lumen (TL).
• The precise mechanisms driving FL formation in SCAD remain incompletely understood.

Purpose of the Study:

• To investigate the mechanisms of false lumen (FL) formation in spontaneous coronary artery dissection (SCAD).
• To compare differences between fenestrated and nonfenestrated SCAD.
• To assess vasa vasorum density and light attenuation characteristics of the FL in SCAD.

Main Methods:

• Utilized optical coherence tomography (OCT) in 65 SCAD patients (68 vessels).
• Classified images based on the presence or absence of a fenestration between the TL and FL.
• Measured TL stenosis, external elastic lamina (EEL) area, FL area, FL light attenuation, and compared vasa vasorum density with control subjects.

Main Results:

• Nonfenestrated SCAD showed significantly larger EEL area expansion (9.1% vs -1.9%) and FL area (73.6% vs 53.2%) compared to fenestrated SCAD.
• No significant difference in vasa vasorum density was observed between SCAD cases and control subjects.
• FL contents were heterogeneous, with lower light attenuation (4.28 mm⁻¹) compared to whole blood or thrombus.

Conclusions:

• Absence of a fenestration in SCAD may lead to increased FL pressure and TL compression.
• While vasa vasorum might play a role in SCAD pathogenesis, increased density could be related to vascular healing.
• OCT provides insights into FL formation mechanisms in SCAD.