SAN FRANCISCO – according to an investigation from Johns Hopkins University, Baltimore.
M. Alexander Otto/MDedge News
Dr. George Stojan
All of the 102 lupus patients in the coronary artery CT angiography study also had positive plaque remodeling, meaning that at least one low-attenuation plaque was growing into the lumen wall, not the lumen itself, which makes them difficult to detect on standard imaging. Low-attenuation plaques were defined in the study as a plaque larger than 1 mm2 with a radiodensity below 30 Hounsfield units.
Low-attenuation plaques are inherently unstable; they’re fatty, necrotic, and have a high risk of rupturing; their presence in the lumen wall is especially worrisome. In the general population, they sometimes regress, scarring down over time and no longer posing a threat. That didn’t happen in the 30 lupus patients who had follow-up CT angiographies, some 9 years after their first.
The team conducted the study to help understand why cardiovascular disease is so common in lupus, and the leading cause of death. Hopkins investigators have shown previously that statins have no effect on the risk or plaque occurrence and progression, and the cardiovascular risk doesn’t always seem to correlate with disease control. For those and other reasons, the current thinking at Hopkins is that cardiovascular disease in lupus is somehow different than in the general population, said George Stojan, MD, an assistant professor of rheumatology at the school and codirector of the Hopkins Lupus Center.
The goal is “to figure out exactly what to look for when we assess the risk; I don’t think we understand that at this point. We assume patients with lupus behave exactly like patients who don’t have lupus, but they obviously don’t. They do not respond to statins. They have a higher risk no matter what you do for them, even when their disease activity is low, and how much plaque they have over time doesn’t really correlate with disease activity,” he said at an international conference on systemic lupus erythematosus.
“Once we understand” the mechanism, “then we can try to [alter] it. Maybe we can look at new drugs, like the PCSK9 inhibitors which have shown a lot of promise in the general population.” At this point, however, “we don’t really know how to intervene,” Dr. Stojan said.
In the meantime, positive remodeling and low-attenuation, noncalcified plaques (LANCPs) might be something to look for when assessing systemic lupus erythematosus cardiovascular risk. “A simple coronary calcium score, something that all doctors do,” is not enough in lupus, nor is simply checking for lumen obstruction. Also, it’s important not to be misled by an overall reduction in noncalcified plaques. “Low-attenuation, noncalcified plaques don’t [regress] over time in lupus, and they are the ones that lead to cardiovascular events,” he said.
The CT angiography findings were compared with findings in 100 healthy controls who had two CT angiograms in a University of California, Los Angeles, cohort. Overall, there was a mean of 458 LANCPs among lupus patients, versus 42 among controls, a more than 900% difference (P less than .001).
Women with lupus aged under 44 years had a mean of 63 LANCPs; none were detected in healthy women under 44 years. Among women aged 45-59 years, there was a mean of 451 LANCPs in the lupus group versus 53 in the control arm. The findings were highly statistically significant, and almost statistically significant for women 60 years or older, 695 lesions among lupus patients versus 22 (P = .0576).
There were only nine men with lupus in the study, but the findings were similar versus male controls.
While mean LANCP volume regressed over time in the control group (mean, –6.90 mm3; P = .0002), a mean regression of –13.56 mm3 in the lupus group was not statistically significant (P = .4570).
Both controls and lupus patients had a positive remodeling index. It progressed in the lupus group over time, and regressed in controls, but the findings were not statistically significant.
“Statins did nothing for the lupus patients. They didn’t affect progress of coronary plaques at all. We still treat patients because theoretically we don’t have anything better, but we know that they don’t really work in this population,” Dr. Stojan said
The work is funded by the National Institutes of Health. Dr. Stojan didn’t report any relevant disclosures.
SOURCE: Stojan G et al. Lupus Sci Med. 2019;6[suppl 1]:A200, Abstract 274.