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Identifying Vulnerable Plaque Using Advanced Coronary Imaging
Quick Takes
- Advanced coronary imaging using both IVUS and NIRS can identify vulnerable plaque in nonculprit lesions among patients presenting with acute myocardial infarction.
- Large plaque burden and high lipid content, when seen with a combined NIRS and IVUS imaging catheter, predict future adverse cardiac events.
- Whether widespread adoption of three-vessel intracoronary imaging is possible and whether targeted therapies of ‘vulnerable’ plaque will help improve cardiovascular morbidity and mortality remains to be determined.
Study Questions:
Can combined use of near-infrared spectroscopy (NIRS) and intravascular ultrasound (IVUS) identify high-risk plaques and patients that are at risk for future major adverse cardiac events (MACE)?
Methods:
PROSPECT II is an investigator-sponsored, multicenter, prospective natural history study done at 14 university hospitals and two community hospitals in Denmark, Norway, and Sweden. They recruited patients of any age with a recent (within past 4 weeks) myocardial infarction. After treatment of all flow-limiting coronary lesions, three-vessel imaging was done with a combined NIRS and IVUS catheter. Untreated lesions (also known as nonculprit lesions) were identified by IVUS and their lipid content was assessed by NIRS. The primary outcome was the covariate-adjusted rate of MACE (the composite of cardiac death, myocardial infarction, unstable angina, or progressive angina) arising from untreated nonculprit lesions during follow-up. The relations between plaques with high lipid content, large plaque burden, and small lumen areas and patient-level and lesion-level events were determined.
Results:
Between June 10, 2014, and December 20, 2017, 3,629 nonculprit lesions were characterized in 898 patients (153 [17%] women, 745 [83%] men; median age, 63 [interquartile range, 55–70] years). Median follow-up was 3.7 (interquartile range, 3.0–4.4) years. Adverse events within 4 years occurred in 112 (13.2%, 95% confidence interval [CI], 11.0–15.6) of 898 patients, with 66 (8.0%, 95% CI, 6.2–10.0) arising from 78 untreated nonculprit lesions (mean baseline angiographic diameter stenosis, 46.9% [standard deviation, 15.9]). Highly lipidic lesions (851 [24%] of 3,500 lesions, present in 520 [59%] of 884 patients) were an independent predictor of patient-level nonculprit lesion-related MACE (adjusted odds ratio, 2.27; 95% CI, 1.25–4.13) and nonculprit lesion-specific MACE (adjusted odds ratio, 7.83; 95% CI, 4.12–14.89). Large plaque burden (787 [22%] of 3,629 lesions, present in 530 [59%] of 898 patients) was also an independent predictor of nonculprit lesion-related MACEs. Lesions with both large plaque burden by IVUS and large lipid-rich cores by NIRS had a 4-year nonculprit lesion-related MACE rate of 7.0% (95% CI, 4.0–10.0). Patients in whom one or more such lesions were identified had a 4-year nonculprit lesion-related MACE rate of 13.2% (95% CI, 9.4–17.6).
Conclusions:
Combined NIRS and IVUS detects angiographically nonobstructive lesions with a high lipid content and large plaque burden that are at increased risk for future adverse cardiac outcomes.
Perspective:
The current study highlights prognostic implications of using advanced intracoronary imaging to identify vulnerable, nonculprit plaque among patients presenting with acute myocardial infarction. Data from this predominantly male cohort showed that NIRS and IVUS assessment to identify vulnerable plaque (high plaque burden and high lipid content) predicted increased risk of future cardiac events related to these nonculprit lesions. Whether targeted therapies of ‘vulnerable’ plaque will help improve cardiovascular morbidity and mortality remains to be determined. In addition, widespread adoption of three-vessel intracoronary imaging would have to be considered.
Clinical Topics: Acute Coronary Syndromes, Dyslipidemia, Noninvasive Imaging, Lipid Metabolism, Echocardiography/Ultrasound
Keywords: Acute Coronary Syndrome, Angina, Unstable, Cardiac Catheters, Cardiology Interventions, Constriction, Pathologic, Diagnostic Imaging, Lipids, Myocardial Infarction, Plaque, Atherosclerotic, Spectroscopy, Near-Infrared, Ultrasonography, Ultrasonography, Interventional
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