OCT tops IVUS, NIRS for predicting periprocedural MI

And the winner is … optical coherence tomography (OCT). A head-to-head comparison of three imaging modalities found that OCT was the sole independent predictor of periprocedural MI in patients with coronary artery disease.

Annapoorna S. Kini, MD, of Mount Sinai Hospital in New York City, and colleagues retrospectively studied data from 110 consecutive patients who were referred to the hospital’s catheterization laboratory for evaluating coronary artery disease. Each patient underwent OCT, intravascular ultrasound (IVUS) and near infrared spectroscopy (NIRS) imaging on the same segments of the same coronary artery before PCI. Their records included cardiac troponin levels at baseline, six hours and 24 hours after PCI.

They divided patients into two groups: those with a post-PCI cardiac troponin level three or more times higher than the upper limit of normal and those with levels below three times the upper limit of normal. Using another definition of MI, they looked at patients with measurements five or more times higher than the upper limit of normal.

Ten patients had post-PCI cardiac troponin levels three or more times higher than the upper limit of normal; eight of those 10 had levels five or more times higher. By OCT, patients with three times or more higher levels were more likely to have a thin fibrous cap (90 percent vs. 20 percent for patients with levels below three times the upper limit of normal) and have thin cap fibroatheroma (80 percent vs. 19 percent, respectively.)

By IVUS, patients with elevated cardiac troponin levels overall had a smaller cross-section area, larger plaque burden and were more likely to have attenuated plaques than patients in the lower level group. The maximum 4-mm lipid core burden index as measured by NIRS was more likely to be higher in the elevated level group than in the lower level group.

Cap thickness verified by OCT remained the only independent predictor of periprocedural MI in a multivariate logistic regression analysis. Take fibrous cap thickness findings by OCT from the mix and plaque burden by IVUS and lipid core by NIRS became the best metrics for predicting periprocedural MI.

“It is reasonable, then, to deduce that OCT may offer the best imaging modality for predicting periprocedural MI,” Kini et al wrote. “If the OCT is not available, a combination of IVUS and NIRS may be the subsequent option.”

Cardiologists who detect high-risk plaques by imaging might consider treating those patients with more potent antiplatelet therapy to reduce the risk of periprocedural MI, they advised.

The researchers described their results as hypothesis generating only because of the small number of patients in the study with elevated cardiac troponin levels and other limitations. They recommended a larger study be conducted.

They pubished the study in the June issue of the Journal of the American College of Cardiology: Cardiovascular Interventions.