Association Between Physiological Significance and Vulnerable Plaque Characteristics in Patients With Myocardial Infarction: A Prospect II Substudy.

BACKGROUND

Hemodynamically obstructive coronary plaques may contain more vulnerable plaque characteristics than nonobstructive lesions.

OBJECTIVES

The authors aimed to assess whether pressure-wire-based physiologic indices in nonculprit lesions are associated with vulnerable plaque characteristics.

METHODS

In the PROSPECT II study, patients with recent myocardial infarction underwent coronary angiography and culprit lesion percutaneous coronary intervention plus combined near-infrared spectroscopy and intravascular ultrasound assessment of all 3 coronary arteries. Instantaneous wave-free ratio (iFR) or fractional flow reserve (FFR) measurements were performed in intermediate lesions with angiographic stenosis >40%.

RESULTS

Among 898 patients, 319 angiographically intermediate lesions in 275 patients had matched intravascular ultrasound/near-infrared spectroscopy and FFR/iFR measurements; 96 (30.1%) lesions were physiologically significant (FFR ≤0.80 or iFR ≤0.89) and 223 (69.9%) were not. Physiologically significant lesions, compared with those that were not, more likely had a minimal lumen area ≤4.0 mm2 (96.9% vs 83.9%), plaque burden ≥70% (92.7% vs 71.3%) and maximum lipid core burden index in any 4 mm segment of the lesion ≥324.7 (57.0% vs 45.4%). By multivariable analysis, lesion location in the left anterior descending artery, small minimal lumen area, and larger plaque burden were independently associated with physiologic significance, whereas maximum lipid core burden index in any 4 mm segment of the lesion was not.

CONCLUSIONS

In patients with recent myocardial infarction, angiographically intermediate but physiologically significant coronary lesions were more likely to have high-risk vulnerable plaque features compared with nonphysiologically significant stenoses. However, coronary lesions without physiological significance also had a moderate-to-high prevalence of high-risk plaque characteristics, which may explain the residual risk associated with conservative noninterventional management of these lesions. (Providing Regional Observations to Study Predictors of Events in the Coronary Tree II [PROSPECT II]; NCT02171065).