Introductions: It has been widely recognized that acute coronary syndrome develops from plaque disruption followed by obstructive thrombus formation. Sometimes, on the other hand, non-obstructive coronary artery disease (Non-Obstructive CAD, stenosis severity less than 50%) may also cause acute chest pain. A recent meta-analysis showed that the prognosis of acute chest pain patients with Non-Obstructive CAD includes a high risk of cardiovascular mortality and morbidity. However, no study has clarified the detailed lesion characteristics of acute chest pain patients with Non-Obstructive CAD or identified why acute chest pain with Non-Obstructive CAD is associated with poor prognoses.
Hypothesis: The hypothesis of this study is that lesion characteristics of culprit arteries are relevant to poor prognosis of acute chest pain with Non-Obstructive CAD.
Methods: This study consisted of 87 consecutive acute chest pain patients with Non-Obstructive CAD who underwent OCT. Based on the presence of vulnerable lesions in the culprit artery; we classified the acute chest pain patients with vulnerable lesions (VL) group and without vulnerable lesions (NVL) group. A systematic clinical follow-up was performed at our outpatient clinic for up to 24 months. We defined cardiac death, myocardial infarction, and re-hospitalization for recurrent acute chest pain with obstructive coronary stenosis as a cardiac event.
Results: OCT revealed that 49 (56.3%) of 87 patients had hidden vulnerable lesions in the culprit artery, including ruptured plaque (19.5%), calcified nodule (10.3%), lone thrombus (9.2%), thin-cap fibroatheroma (8.0%), spontaneous coronary artery dissection (8.0%), and plaque erosion (1.1%). Of the patient characteristics recorded, only troponin elevation was different between the two groups (VL 36.7% vs. NVL 13.2%, p=0.015). Patients in the VL group had poorer prognoses than those in the NVL group (p=0.042).
Conclusions: Hidden vulnerable lesions accompany acute chest pain patients with Non-Obstructive CAD, resulting in poorer outcomes. OCT would be useful for the management of acute chest pain patients with Non-Obstructive CAD.