This study consisted of 39 patients with STEMI who underwent primary PCI within 24 h after the onset of chest pain. Immediately after thrombectomy, OCT was performed and length of lipid pool was measured. Microvascular reperfusion after primary PCI was assessed by ST-R, which was defined as >50 % decrease in ST elevation at 1 h after primary PCI.
There were 23 patients with ST-R and 16 patients without ST-R, with no significant difference in baseline clinical and angiographical variables between the 2 groups. Final thrombolysis in myocardial infarction 3 flow was obtained in all of the patients. Peak creatine kinase was significantly higher in the ST-R (?) group than in the ST-R (+) group (p = 0.01). Length of lipid pool was 10.1 ¡À 2.8 mm in the ST-R (?) group and 7.8 ¡À 3.2 mm in the ST-R (+) group (p = 0.02). In receiver operating characteristics curve assessing the ability of length of lipid pool to predict ST-R, area under the curve was 0.74 (p = 0.02). Length of lipid pool >9.0 mm best predicted the absence of ST-R with sensitivity 88 % and specificity 78 % .
These findings suggest that length of lipid pool estimated by OCT may predict microvascular no-reflow after primary PCI.