Rupture of a Non-Obstructive Plaque

J INVASIVE CARDIOL 2018;30(4):E33-E34.

Key words: acute coronary syndromes, fractional flow reserve, cardiac imaging

A 54-year-old female with history of hypertension, hiatal hernia repair, and family history of premature maternal death from myocardial infarction presented with substernal non-radiating chest pain. Electrocardiography showed normal sinus rhythm with no ST-segment deviation or T-wave inversion (negative Wellens sign) and initial troponin I was 0.43 ng/mL. Coronary computed tomography angiogram (CTA) revealed a non-obstructive lipid-rich plaque in the proximal left anterior descending (LAD) artery (Figure 1A). CT-based assessment of non-invasive fractional flow reserve (FFR) was negative (Figure 1B). However, there was evidence for intimal disruption and contrast extravasation within the non-obstructive proximal LAD plaque concerning for plaque rupture (Figure 1E). Troponin I peaked at 3.99 ng/mL. Echocardiography revealed normal ejection fraction of 65% with no regional wall-motion abnormalities. Given high clinical suspicion for acute coronary syndromes (ACS) and concerning CTA findings, the patient underwent invasive coronary angiography that was consistent with the non-invasive coronary CTA findings of a non-obstructive proximal LAD plaque (Figure 1C; Video 1), with a negative invasive FFR value (Figure 1D). Intracoronary imaging by optical coherence tomography (OCT) revealed evidence for intimal disruption and rupture of the non-obstructive lipid-rich plaque with thin-cap fibroatheroma (TCFA) and a residual thrombus formation, all consistent with features of ACS (Figure 1F). 

This invasive and non-invasive imaging series represents a classic rupture of a non-obstructive plaque with TCFA. Natural history studies of atherosclerosis demonstrated the significance of TCFA presence as well as the expansive remodeling of plaque in predicting future major adverse cardiovascular events despite only mild luminal stenosis. The proximal portion of the LAD artery represents the most common location for TCFA (~43%), and plaque rupture represents 55%-65% of the underlying pathologic features in patients with sudden cardiac death. The diagnosis of ACS despite the finding of a non-obstructive plaque requires maintaining an appropriate level of clinical suspicion when approaching such cases.

From Harrington Heart and Vascular Institute, University Hospitals, Cleveland Medical Center, Cleveland, Ohio.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Bezerra is a consultant for St. Jude Medical and Heartflow. The remaining authors report no conflicts of interest regarding the content herein.

Manuscript accepted August 24, 2017. 

Address for correspondence: Hiram G. Bezerra, MD, PhD, Harrington Heart and Vascular Institute, University Hospitals, 11100 Euclid Avenue, Lakeside 3113, Cleveland, OH 44106. Email: Hiram.Bezerra@UHhospitals.org