Atherosclerotic plaques occur in absence of intima-media thickening in both systemic sclerosis and systemic lupus erythematosus: a duplexsonography study of carotid and femoral arteries and follow-up for cardiovascular events

Abstract

Introduction: The objective of this cross-sectional and retrospective cohort study was (1) to determine the usefulness of intima-media thickness (IMT) in contrast to plaque assessment, (2) to examine the value of additive femoral artery sonography and (3) to identify potential risk factors for atherosclerosis and incident cardiovascular events in systemic sclerosis (SSc) and systemic lupus erythematosus (SLE) patients.

Methods: In this study, 90 SSc and 100 SLE patients were examined by duplexsonography. IMT was measured in common carotid and common femoral arteries, plaques were assessed in common, internal and external carotid and common, proximal superficial and deep femoral arteries. Different definitions of pathological IMT (pIMT) were compared with the presence of plaque. Results were evaluated in relation to traditional and non-traditional risk factors for baseline atherosclerosis (logistic regression) and their predictive value for cardiovascular events during follow-up (cox regression).

Results: Definite atherosclerosis occurred frequently without signs of subclinical atherosclerosis in both diseases: pIMT >0.9 mm was present in only 17/59 (28.9%) SSc and 13/49 (26.5%) SLE patients with already present atherosclerotic plaques. Using age-adjusted pIMT definitions, this rate was even lower (5.1-10.3% in SSc, 14.3-26.5% in SLE). Plaques were located only at the carotid or only at the femoral arteries in 26 (13.7%) and 24 (12.6%) patients, respectively. Age and nicotine pack-years were independently associated with atherosclerotic plaques in SLE and SSc patients, as well as the cumulative prednisolone dose in SSc subgroup, and ssDNA positive SLE patients had a lower risk for atherosclerotic plaque. During follow-up (available for 129/190 (67.9%) patients, 650 person-years), cardiovascular events occurred more often in patients with coronary heart disease (adjusted-hazards ratio (HR) 10.19, 95% confidence interval (CI) 3.04 to 34.17, P <0.001), male patients (adjusted-HR 8.78, 95% CI 2.73 to 28.19, P <0.001) and in patients with coexistent carotid and femoral plaques (adjusted-HR 5.92, 95% CI 1.55 to 22.67, P = 0.009). Patients with solely carotid or femoral plaque were not at higher risk.

Conclusion: Atherosclerotic plaque lesions can be found frequently in absence of intima-media thickening in both SSc and SLE patients. As well as routine sonography of carotid arteries, the sonography of femoral arteries is recommended to identify additional atherosclerotic lesions and to detect patients at a high risk for cardiovascular events.

Figure 1

Distribution of carotid artery plaques in our cohort of systemic sclerosis and systemic lupus erythematosus patients. Carotid artery plaques are mostly located at the internal carotid artery (ICA) and the region of the bulb, and are rarely observed at the external carotid artery (ECA) and the common carotid artery (CCA). An extension of carotid ultrasound examination distal to the CCA segment for plaque assessment is highly recommended.

Figure 2

Incidence and rate ratios of cardiovascular events during follow-up according to the presence of plaque. Incidence of cardiovascular events per 100 person-years (py) during follow-up available for 129/190 (67.9%) patients (650 person-years, mean 60.5 months, median 65.5 months, range 8 to 82 months) according to the presence of carotid and femoral artery plaque. The rate ratio (RR) was approximately 6.5 for patients with carotid and femoral artery plaque in contrast to patients with only one vascular segment affected and was 8.7 compared with patients without plaque. CI, confidence interval.

Figure 3

Kaplan–Meier survival curves for the time to first cardiovascular event according to the presence of plaque. Kaplan–Meier survival curves for the time to first cardiovascular event during follow-up and results of a log-rank test stratified by (A) systemic sclerosis (SSc) and (B) systemic lupus erythematosus (SLE) according to the presence of carotid and femoral artery plaques. Group 1, patients without carotid or femoral artery plaque; group 2, patients with only carotid or only femoral artery plaque; group 3, patients with coexistent carotid and femoral artery plaque.