Background: Intravascular polarization-sensitive optical frequency domain imaging (PS-OFDI) offers a novel approach to measure tissue birefringence, which is elevated in collagen and smooth muscle... Show moreBackground: Intravascular polarization-sensitive optical frequency domain imaging (PS-OFDI) offers a novel approach to measure tissue birefringence, which is elevated in collagen and smooth muscle cells, that in turn plays a critical role in healing coronary thrombus (HCT). This study aimed to quantitatively assess polarization properties of coronary fresh and organizing thrombus with PS-OFDI in patients with acute coronary syndrome (ACS).Methods and Results:The POLARIS-I prospective registry enrolled 32 patients with ACS. Pre-procedural PS-OFDI pullbacks using conventional imaging catheters revealed 26 thrombus-regions in 21 patients. Thrombus was manually delineated in conventional OFDI cross-sections separated by 0.5 mm and categorized into fresh thrombus caused by plaque rupture, stent thrombosis, or erosion in 18 thrombus-regions (182 frames) or into HCT for 8 thrombus-regions (141 frames). Birefringence of coronary thrombus was compared between the 2 categories. Birefringence in HCTs was significantly higher than in fresh thrombus (Delta n=0.47 (0.37-0.72) vs. Delta n=0.25 (0.17-0.29), P=0.007). In a subgroup analysis, when only using thrombus-regions from culprit lesions, ischemic time was a significant predictor for birefringence (ss (Delta n)=0.001 per hour, 95% CI [0.0002-0.002], P=0.023).Conclusions: Intravascular PS-OFDI offers the opportunity to quantitatively assess the polarimetric properties of fresh and organizing coronary thrombus, providing new insights into vascular healing and plaque stability. Show less
Background: Coronary computed tomography angiography (cCTA)-derived fractional flow reserve (FFRCT) is a promising diagnostic method for the evaluation of coronary artery disease (CAD). However,... Show moreBackground: Coronary computed tomography angiography (cCTA)-derived fractional flow reserve (FFRCT) is a promising diagnostic method for the evaluation of coronary artery disease (CAD). However, clinical data regarding FFRCT in Japan are scarce, so we assessed the clinical impact of using FFRCT in a Japanese population.Methods and Results: The ADVANCE registry is an international prospective FFRCT registry of patients suspected of CAD. Of 5,083 patients, 1,829 subjects enrolled from Japan were analyzed. Demographics, symptoms, cCTA, FFRCT, treatment strategy, and 90-day major cardiovascular events (MACE) were assessed. Reclassification of treatment strategy between cCTA alone and cCTA+ FFRCT occurred in 55.8% of site investigations and in 56.9% in the core laboratory analysis. Patients with positive FFR (FFRCT =0.80) were less likely to have non-obstructive disease on invasive coronary angiography than patients with negative FFR (FFRCT > 0.80) (20.5% vs. 46.1%, P=0.0001). After FFRCT, 67.0% of patients with positive results underwent revascularization, whereas 96.1% of patients with negative FFRCT were medically treated. MACE occurred in 5 patients with positive FFRCT, but none occurred in patients with negative FFRCT within 90 days.Conclusions: In this Japanese population, FFRCT modified the treatment strategy in more than half of the patients. FFRCT showed potential for stratifying patients suspected of CAD properly into invasive or non-invasive management pathways. Show less
