Clinical Investigation
Coronary Artery Disease
Characteristics of plaque disruption by intravascular ultrasound in women presenting with myocardial infarction without obstructive coronary artery disease

https://doi.org/10.1016/j.ahj.2014.01.011Get rights and content

Background

In a prospective study, we previously identified plaque disruption (PD: plaque rupture or ulceration) in 38% of women with myocardial infarction (MI) without angiographically obstructive coronary artery disease (CAD), using intravascular ultrasound (IVUS). Underlying plaque morphology has not been described in these patients and may provide insight into the mechanisms of MI without obstructive CAD.

Methods

Forty-two women with MI and <50% angiographic stenosis underwent IVUS (n = 114 vessels). Analyses were performed by a blinded core laboratory. Sixteen patients had PD (14 ruptures and 5 ulcerations in 18 vessels). Plaque area, % plaque burden, lumen area stenosis, eccentricity, and remodeling index were calculated for disrupted plaques and largest plaque by area in each vessel.

Results

Disrupted plaques had lower % plaque burden than the largest plaque in the same vessel (31.9% vs 49.8%, P = .005) and were rarely located at the site of largest plaque (1/19). Disrupted plaques were typically fibrous and were not more eccentric or remodeled than the largest plaque in the same vessel.

Conclusions

Plaque disruption was often identifiable on IVUS in women with MI without obstructive CAD. Plaque disruption in this patient population occurred in fibrous or fibrofatty plaques and, contrary to expectations based on prior studies of plaque vulnerability, did not typically occur in eccentric, outwardly remodeled, or soft plaque in these patients. Plaque disruption rarely occurred at the site of the largest plaque in the vessel. These findings suggest that the pathophysiology of PD in women with MI without angiographically obstructive CAD may be different from MI with obstructive disease and requires further investigation.

Section snippets

Methods

The study was approved by the New York University Langone Medical Center and Bellevue Hospital Center Institutional Review Boards. All patients provided informed consent.

Patient characteristics

Among 42 patients who underwent IVUS, PDs were found in 16 patients. Ischemic ECG findings were seen in 75% of patients with PD and abnormal left ventricular wall motion in 56%. There were no differences in peak troponin or left ventricular ejection fraction between those with and without PD (Table I).4 There was no difference in traditional CAD risk factors between the 2 groups, except for high-density lipoprotein cholesterol, which was significantly lower in the PD group. Two patients without

Discussion

Our findings indicate that PD in women with MI without obstructive CAD tends to occur in vessels with more plaque, whether measured by angiography or IVUS. However, contrary to expectations, PD rarely occurred in the largest plaque in the vessel and was often located in areas of the vessel that were angiographically normal. Outward remodeling was observed in only 21% of PD sites, and median remodeling index was 1.00. The predominant plaque morphologies at the disruption site were fibrous and

Conclusions

In our cohort of women with MI and without obstructive CAD, PD was found in women with more angiographic CAD but did not typically occur at the site of the largest plaque area, in soft plaques, or eccentric or outwardly remodeled plaques. In comparison with published literature using IVUS in obstructive CAD in predominantly male populations, disrupted plaques in this study were more fibrous, were less outwardly remodeled, and had lower % plaque burden. Therefore, the concept that plaque rupture

Disclosures

Drs Feit and Yatskar hold stock, and Dr Attubato lectures for Boston Scientific Corp.

Acknowledgements

The authors thank Yu Guo for her assistance in statistical analysis. Dr Reynolds is the recipient of a Doris Duke Charitable Foundation Clinical Scientist Development Award.

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