Longitudinal extent of lipid pool assessed by optical coherence tomography predicts microvascular no-reflow after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction.

BACKGROUND: Distal embolization during percutaneous coronary intervention (PCI) may deteriorate microvascular reperfusion in patients with ST-elevation myocardial infarction (STEMI). Reperfusion at the coronary microvascular level is important for STEMI and culprit plaque is associated with distal embolization and microvascular reperfusion. ST-segment resolution (ST-R) in the electrocardiogram reflects microvascular reperfusion after primary PCI. Longitudinal extent of lipid pool assessed by optical coherence tomography (OCT) may predict the risk of failure of microvascular reperfusion after primary PCI.

METHODS AND RESULTS: This study consisted of 39 patients with STEMI who underwent primary PCI within 24h 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 1h 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 ± 2.8mm in the ST-R (-) group and 7.8 ± 3.2mm 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 >9.0mm best predicted the absence of ST-R with sensitivity 88% and specificity 78%.

CONCLUSIONS: These findings suggest that length of lipid pool estimated by OCT may predict microvascular no-reflow after primary PCI.