Optical coherence tomography (OCT) enabled the stratification of future major adverse cardiac event (MACE) risk in acute coronary syndrome (ACS) patients indicated for primary percutaneous coronary intervention (PCI) in a new observational Japanese study.
The results were presented Monday at the Transcatheter Cardiovascular Therapeutics (TCT) conference in Boston by Toshiro Shinke, MD, PhD, from Showa University, Tokyo.
Shinke noted that recent retrospective studies have suggested that OCT enables the diagnosis of the underlying causes of ACS such as plaque rupture, plaque erosion and calcified nodule, but the relationship between those etiologies and clinical outcomes have not been systematically addressed in the real world.
The current study, therefore, set out to identify the prevalence of underlying ACS causes using OCT-defined morphological assessment of the culprit lesion and its impact on clinical outcomes in 695 subjects treated by OCT-guided primary PCI across 22 hospitals in Japan.
Of these, 64 patients (9.1%) had significant stenosis, seven (1%) had coronary spasm, three (0.4%) had ectasia, three (0.4%) had embolism and one (0.1%) had spontaneous coronary dissection.
Plaque rupture was the most common underlying ACS cause detected using the OCT-guided strategy (in 411 patients; 59%), followed by plaque erosion (178 patients; 26%) and calcified nodule (28 patients; 4%). The remaining 78 patients (11%) had underlying ACS causes defined as “other.”
However, despite being the rarest cause of ACS, a Kaplan-Meier time-to-event curve for the cumulative rate of MACE showed that calcified nodule carried the highest risk. The cumulative rate of MACE for calcified nodule was 32.1% (unadjusted hazard ratio [HR]: 6.81; 95% confidence interval [CI]: 2.81-16.49; p<0.001).
This is compared to a cumulative rate of MACE of 12.4% for plaque rupture (unadjusted HR: 2.2; 95% CI: 1.15-4.22; p = 0.018) and for plaque erosion 6.2% (plaque erosion as reference).
"Underlying causes of ACS defined by OCT enable us to stratify the future risk of MACE in ACS patients indicated for primary PCI," according to Shinke's presentation
He called for further study to reveal whether OCT could optimize primary PCI in each underlying cause of ACS.
The study was funded by Abbott Medical Japan.
Image Credit: Jason Wermers/CRTonline.org