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Several metabolites may be associated with myocardial ischemia
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Five metabolites were identified within 2 hours of a stress test in patients with myocardial ischemia, according to a study published in PLOS ONE.
“Cardiologists do a stress test to determine who’s at risk for having heart disease,” Alexander T. Limkakeng Jr., MD, director of acute care research and associate professor of surgery at Duke University School of Medicine, said in a press release. “It guides them on whether they need a more invasive study like a catheterization. Augmenting the imaging of a stress test with metabolite biomarkers could make that process more accurate or more efficient.”
Researchers analyzed data from 20 patients (mean age, 56 years; 45% men) with inducible ischemia during stress testing and 20 controls (mean age, 55 years; 45% men) with normal stress tests. Both groups of patients presented to the ED with symptoms suggestive of ACS and underwent blood tests at baseline and 2 hours after an exercise ECG cardiac stress testing to assess acylcarnitines and amino acids. Serial troponin assays were also performed before stress testing.
Other information that was collected included demographics, radiographic testing, laboratory testing and physical exam findings. Events that were recorded were abnormal stress testing, subsequent MI, PCI, significant coronary disease by angiography, CABG or death.
Five metabolites were identified by bivariable analysis that were linked to positive stress tests with false discovery rates less than 0.2, which included alanine, C14:1-OH, C16:1, C18:2 and C20:4.
The area under the receiver-operating characteristic curve in multivariable regularized linear models were between 0.5 and 0.55. However, the log model resulted in an AUC of 0.625 with 60% specificity (interquartile range [IQR], 0.667-0.524) and 65% sensitivity (IQR, 0.57-0.72).
The model selected the following metabolites: arginine, alanine, C12-OH/C10-DC, C14:1-OH, C16:1, C18:2, C18:1, C20:4 and C18:1-DC.
Comparisons of metabolite levels or changes in metabolite levels did not directionally change when defining cases in patients with CABG or angiographically proven stenosis.
“It is unclear whether these results can contribute additional information above standard clinical evaluation for myocardial ischemia,” Limkakeng and colleagues wrote. “Delta-metabolite concentrations may offer more discriminative value than static single-timepoint metabolite measurement. This model of metabolomic exploration warrants further investigation.” – by Darlene Dobkowski
Disclosures: The study was funded by an ENABLE grant from the Duke Private Diagnostic Clinics and Duke University. Limkakeng reports he received research grants from Abbott Laboratories, Roche International and Siemens Healthcare Diagnostics. Please see the study for all other authors’ relevant financial disclosures.
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