In Vivo Comparison of Optical Coherence Tomography and Angioscopy for the Evaluation of Coronary Plaque Characteristics

doi:10.1016/j.amjcard.2007.09.106

The American Journal of Cardiology

Volume 101, Issue 4, 15 February 2008, Pages 471-476

https://doi.org/10.1016/j.amjcard.2007.09.106 Get rights and content

Atherosclerotic yellow plaques identified by coronary angioscopy are considered as vulnerable plaques. However, characteristics of yellow plaques are not well understood. Optical coherence tomography (OCT) provides accurate tissue characterization in vivo and has the capability to measure fibrous cap thickness covering a lipid plaque. Characteristics of yellow plaques identified by angioscopy were evaluated by OCT. We examined 205 plaques of 41 coronary arteries in 26 patients. In OCT analysis, plaques were classified as fibrous or lipid. Minimal lumen area of the plaque, arch of the lipid, and fibrous cap thickness on the lipid plaque were measured. Yellow grade of the plaque was defined as 0 (white), 1 (light yellow), 2 (medium yellow), or 3 (dark yellow) based on the angioscopy. A total of 149 plaques were diagnosed as lipid plaques. Neither the minimal lumen area nor the arch of the lipid was related to the yellow grade. There was an inverse relationship between color grade and the fibrous cap thickness (grade 0 [n = 45] 218 ± 89 μm, grade 1 [n = 40] 101 ± 8 μm, grade 2 [n = 46] 72 ± 10 μm, and grade 3 [n = 18] 40 ± 14 μm; p <0.05). Sensitivity and specificity of the angioscopy-identified yellow plaque for having a thin fibrous cap (thickness ≤110 μm) were 98% and 96%, respectively. In conclusion, angioscopy-identified yellow plaques frequently were lipid tissue with an overlying thin fibrous cap. Fibrous caps of the intense yellow plaques were very thin, and these plaques might be structurally vulnerable.

Section snippets

Patient population and clinical demographics

Between August 2006 and January 2007, 26 consecutive patients who consented to undergo catheter procedures using OCT and angioscopy were enrolled in the study. The exclusion criteria included unprotected left main disease (n = 4), renal insufficiency with baseline serum creatinine ≥2.0 mg/dl (n = 6), congestive heart failure (n = 4), low ejection fraction (<40%; n = 5), or conditions that required emergency coronary intervention (n = 22). Patients with extremely tortuous vessels (n = 9),

Baseline characteristics

The clinical characteristics of 26 patients are listed in Table 1. Ten patients underwent catheterization as follow-up studies after stent implantation. There were no procedure-related complications except for transient myocardial ischemia during angioscopic and OCT observations.

Plaque characteristics

A total of 205 plaques were recognized, and 16 plaques were culprit plaques (7 in ACS and 9 in SAP). The plaque characteristics are listed in Table 2. Based on OCT findings, 56 plaques were diagnosed as fibrous plaques

Discussion

This study verified the pathohistological characterization of the angioscopic yellow plaque in coordination with OCT. The yellow plaques frequently had lipid under the thin fibrous cap. The overlying fibrous cap thickness became thinner in plaques with higher yellow grades. Although yellow plaques identified by angioscopy have been viewed as vulnerable, there has been limited histopathological investigation of these plaques. Previous examination using specimens obtained by directional coronary

Acknowledgment

We thank Kenichi Tokuyama, MD, Kenichiro Tajika, MD, Shunsuke Shimada, MSc, Toshihiro Chiba, MSc, Nobuyuki Igawa, MSc, and Masaki Suzuki, MSc, for their excellent assistance in our catheter laboratory.

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Coronary artery diseaseIn Vivo Comparison of Optical Coherence Tomography and Angioscopy for the Evaluation of Coronary Plaque Characteristics

Section snippets

Patient population and clinical demographics

Baseline characteristics

Plaque characteristics

Discussion

Acknowledgment

Lancet

J Am Coll Cardiol

J Am Coll Cardiol

Am J Cardiol

Am Heart J

J Am Coll Cardiol

Am J Cardiol

J Am Coll Cardiol

J Am Coll Cardiol

Am Heart J

Coronary artery disease
In Vivo Comparison of Optical Coherence Tomography and Angioscopy for the Evaluation of Coronary Plaque Characteristics