The combination assessment of lipid pool and thrombus by optical coherence tomography can predict the filter no-reflow in primary PCI for ST elevated myocardial infarction

Abstract

The usefulness of distal protection devices is still controversial. Moreover, there is no report on thrombus evaluation by using optical coherence tomography (OCT) for determining whether to use a distal protection device. The aim of the present study was to investigate the predictor of filter no-reflow (FNR) by using OCT in primary percutaneous coronary intervention (PCI) for ST-elevated acute myocardial infarction (STEMI).We performed preinterventional OCT in 25 patients with STEMI who were undergoing primary PCI with Filtrap. FNR was defined as coronary flow decreasing to TIMI flow grade 0 after mechanical dilatation.FNR was observed in 13 cases (52%). In the comparisons between cases with or without the FNR, the stent length, lipid pool length, lipid pool + thrombus length, and lipid pool + thrombus index showed significant differences. In multivariate analysis, lipid pool + thrombus length was the only independent predictor of FNR (OR 1.438, 95% CI 1.001 - 2.064, P < .05). The optimal cut-off value of lipid pool + thrombus length for predicting FNR was 13.1 mm (AUC = 0.840, sensitivity 76.9%, specificity 75.0%). Moreover, when adding the evaluation of thrombus length to that of lipid pool length, the prediction accuracy of FNR further increased (IDI 0.14: 0.019-0.25, P = .023).The longitudinal length of the lipid pool plus thrombus was an independent predictor of FNR and the prediction accuracy improved by adding the thrombus to the lipid pool. These results might be useful for making intraoperative judgment about whether filter devices should be applied in primary PCI for STEMI.

Figure 1

Flow chart of patients included in the study. IVUS = intravascular ultrasound, OCT = optical coherence tomography, PCI = percutaneous coronary intervention, STEMI = ST-elevated acute myocardial infarction.

Figure 2

Lipid pool and thrombus assessment by optical coherence tomography. In the longitudinal view, lipid pool (white arrowheads) and thrombus (green arrowheads) are observed, and each length can be measured separately while overlap (white or green 2 direction arrow). However, it is difficult to distinguish the presence of lipid pool in the area where a large amount of thrombus exists. The lipid pool + thrombus length was measured not by adding each length together, but by collecting both of them (blue 2 direction arrow). In the cross-sectional image, lipid pool (white arrowheads) and thrombus (green arrowheads) are observed as well as longitudinal view, and their angles can be measured (white or green double arrows arc). In slices (A) and (D), only thrombus or lipid pool existence is confirmed, and both are recognized in slice (C). In slice (B), thrombus is abundant and lipid pool can not be confirmed. Since the posterior side of the thrombus is not clear by the attenuation effect, it was unknown whether lipid pool existed in that part. The unknown part of lipid pool was not included in the measurement, and the lipid pool + thrombus arc was measured so that it does not overlap like the longitudinal view (blue double arrows arc).

Figure 3

Comparison of the length of lipid pool plus thrombus between the both groups.

Figure 4

Receiver-operating characteristic curves of lipid pool length, lipid pool plus thrombus length, lipid pool index, and lipid pool plus thrombus index. AUC = area under the curve, CI = confidence interval.