Background:The new 60-MHz high-resolution intravascular ultrasound (HR-IVUS) is the next-generation IVUS technology, providing higher image resolution than conventional IVUS. It gives clear images of plaque morphology and can discriminate the underlying mechanism of acute coronary syndrome (ACS). Our study aimed to evaluate the diagnostic performance of 60-MHz HR-IVUS in the detection of plaque rupture in patients with ACS.

Methods and Results:Patients with ACS who underwent percutaneous coronary intervention for de novo native coronary artery lesions were enrolled. Both HR-IVUS and optical coherence tomography (OCT) were performed for the culprit lesions prior to interventions other than aspiration thrombectomy. Keeping plaque rupture detected by OCT as the gold standard, the diagnostic performance of HR-IVUS was evaluated. Overall, 70 patients underwent both HR-IVUS and OCT examinations. Of these, imaging assessments by HR-IVUS were available for all 70 patients (100%), and those by OCT were available for 54 patients (77.1%). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of HR-IVUS for identifying a plaque rupture were 84.8%, 57.1%, 75.7%, 70.6%, and 74.1%, respectively.

Conclusions:HR-IVUS had high sensitivity, but modest specificity for identifying OCT-derived plaque rupture. Compared with results from previous conventional IVUS studies, HR-IVUS might have increased ability to detect OCT-derived plaque rupture, but there is still substantial scope for improvement, especially in the specificity.