Impact of Heterogeneity of Human Peripheral Blood Monocyte Subsets on Myocardial Salvage in Patients With Primary Acute Myocardial Infarction

ObjectivesWe examined whether distinct monocyte subsets contribute in specific ways to myocardial salvage in patients with acute myocardial infarction (AMI).BackgroundRecent studies have shown that monocytes in human peripheral blood are heterogeneous.MethodsWe studied 36 patients with primary AMI. Peripheral blood sampling was performed 1, 2, 3, 4, 5, 8, and 12 days after AMI onset. Two monocyte subsets (CD14+CD16−and CD14+CD16+) were measured by flow cytometry. The extent of myocardial salvage 7 days after AMI was evaluated by cardiovascular magnetic resonance imaging as the difference between myocardium at risk (T2-weighted hyperintense lesion) and myocardial necrosis (delayed gadolinium enhancement). Cardiovascular magnetic resonance imaging was also performed 6 months after AMI.ResultsCirculating CD14+CD16−and CD14+CD16+monocytes increased in AMI patients, peaking on days 3 and 5 after onset, respectively. Importantly, the peak levels of CD14+CD16−monocytes, but not those of CD14+CD16+monocytes, were significantly negatively associated with the extent of myocardial salvage. We also found that the peak levels of CD14+CD16−monocytes, but not those of CD14+CD16+monocytes, were negatively correlated with recovery of left ventricular ejection fraction 6 months after infarction.ConclusionsThe peak levels of CD14+CD16−monocytes affect both the extent of myocardial salvage and the recovery of left ventricular function after AMI, indicating that the manipulation of monocyte heterogeneity could be a novel therapeutic target for salvaging ischemic damage

The Role of Optical Coherence Tomography in Coronary Intervention

Optical coherence tomography (OCT) is an optical analog of intravascular ultrasound (IVUS) that can be used to examine the coronary arteries and has 10-fold higher resolution than IVUS. Based on polarization properties, OCT can differentiate tissue characteristics (fibrous, calcified, or lipid-rich plaque) and identify thin-cap fibroatheroma. Because of the strong attenuation of light by blood, OCT systems required the removal of blood during OCT examinations. A recently developed frequency-domain OCT system has a faster frame rate and pullback speed, making the OCT procedure more user-friendly and not requiring proximal balloon occlusion. During percutaneous coronary intervention (PCI), OCT can provide detailed information (dissection, tissue prolapse, thrombi, and incomplete stent apposition [ISA]). At follow-up examinations after stent implantation, stent strut coverage and ISA can be assessed. Several OCT studies have demonstrated delayed neointimal coverage following drug-eluting stent (DES) implantation vs. bare metal stent (BMS) placement. While newer DESs promote more favorable vascular healing, the clinical implications remain unknown. Recent OCT studies have provided insights into restenotic tissue characteristics; DES restenotic morphologies differ from those with BMSs. OCT is a novel, promising imaging modality; with more in-depth assessments of its use, it may impact clinical outcomes in patients with symptomatic coronary artery disease