Predictors of periprocedural (type IVa) myocardial infarction, as assessed by frequency-domain optical coherence tomography.

Background: Frequency-domain optical coherence tomography (FD-OCT) is easily able to define both pre- and post-stenting features of the atherosclerotic plaque that can potentially be related to periprocedural complications. We sought to examine which FD-OCT-defined characteristics, assessed both before and after stent deployment, predicted periprocedural (type IVa) myocardial infarction (MI).
Methods and Results: FD-OCT was performed before and after coronary stenting in 50 patients undergoing percutaneous coronary intervention (PCI) for either non-ST segment elevation MI (NSTEMI) or stable angina. All patients underwent single-vessel stenting, and only drug-eluting stents were implanted. Troponin T was analyzed on admission, before PCI, and at 12 and 24 hours after PCI, and type IVa MI was defined in stable angina as a rise of at least 3× upper reference limit and in NSTEMI as a pre-PCI troponin T fall, followed by post-PCI troponin T rise >20%. Type IVa MI was diagnosed in 21 patients, while the remaining 29 represented the control group. FD-OCT analysis showed that thin-cap fibroatheroma (76.2% versus 41.4%; P=0.017) prior to PCI, intrastent thrombus (61.9% versus 20.7%; P=0.04), and intrastent dissection (61.9% versus 31%; P=0.03) after PCI were significantly more frequent in type IVa MI than in the control group. Multivariate logistic regression analysis confirmed thin-cap fibroatheroma (OR 29.7, 95% CI 1.4 to 32.1), intrastent thrombus (OR 5.5, CI 1.2 to 24.9) and intrastent dissection (OR 5.3, CI 1.2 to 24.3) as independent predictors of type IVa MI.
Conclusions: In conclusion, presence of thin-cap fibroatheroma at pre-PCI FD-OCT and of intrastent thrombus and intrastent dissection at post-PCI FD-OCT predict type IVa MI in a contemporary sample of patients treated with second-generation drug-eluting stents. Interestingly, 2 of the 3 predictors of type IVa MI were not apparent at pre-PCI FD-OCT.