Author + information
- Received July 5, 2007
- Revision received August 30, 2007
- Accepted October 15, 2007
- Published online March 11, 2008.
- Tobias Saam, MD⁎,†,
- Hunter R. Underhill, MD†,
- Baocheng Chu, MD, PhD†,
- Norihide Takaya, MD, PhD†,
- Jianming Cai, MD, PhD†,
- Nayak L. Polissar, PhD‡,
- Chun Yuan, PhD† and
- Thomas S. Hatsukami, MD§,⁎ ()
- ↵⁎Reprint requests and correspondence:
Dr. Thomas S. Hatsukami, VA Puget Sound Health Care System, Surgery and Perioperative Care (112), 1660 South Columbian Way, Seattle, Washington 98108.
Objectives Via magnetic resonance imaging (MRI), we sought to determine the prevalence of atherosclerotic American Heart Association type VI lesions (AHA-LT6) (lesions with luminal surface defect, hemorrhage/thrombus, or calcified nodule) in carotid arteries that represented all categories of stenosis as measured by duplex ultrasound.
Background Arterial stenosis alone has been shown to be a poor predictor of cardiovascular events. Autopsy studies suggest that features associated with AHA-LT6 lesions, rather than the degree of luminal narrowing, characterize the high-risk plaque.
Methods A total of 192 subjects underwent bilateral carotid artery magnetic resonance imaging (MRI) scans at 1.5T after evaluation with ultrasound to determine stenosis. After excluding arteries with a previous endarterectomy, poor image quality, or missing ultrasound data, there were 175 patients with 260 arteries available for analysis. The AHA lesion type was determined by the consensus opinion of 2 experienced carotid MRI reviewers.
Results In total, 96 of 260 (37.0%) arteries had ≥1 location with AHA-LT6. Of the arteries with AHA-LT6, 84.4% had hemorrhage, 45.8% had a ruptured fibrous cap, and 14.6% showed other type of complications. Prevalence of AHA-LT6 was an increasing sequence of 8.1% in the 37 arteries with 1% to 15% stenosis, 21.7% in the 60 arteries with 16% to 49% stenosis, 36.8% in the 114 arteries with 50% to 79% stenosis, and 77.6% in the 49 arteries with 80% to 99% stenosis.
Conclusions Complicated AHA-LT6 are frequently found in arteries with ≤50% stenosis. These findings indicate that complex lesions develop in a substantial number of arteries in the absence of high-grade stenosis. Ongoing prospective studies will determine the predictive value of vulnerable plaque features, as visualized by MRI, for risk of subsequent ischemic events.
Supported by National Institutes of Health grants R01 HL61851, R01 HL073401, P01 HL072262, R01HL56874, and T32 HL07828.
- Received July 5, 2007.
- Revision received August 30, 2007.
- Accepted October 15, 2007.
- American College of Cardiology Foundation