Endothelial dysfunction and brachial intima-media thickness: long term cardiovascular risk with claudication related to peripheral arterial disease: a prospective analysis

Abstract

Objective: Endothelial dysfunction plays a key role in the development, progression, and clinical manifestation of atherosclerosis, and in symptomatic peripheral arterial disease, endothelial dysfunction and enlarged intima-media thickness might be associated with increased cardiovascular risk. Flow-mediated dilatation and serologic parameters are used to evaluate individual endothelial function. Brachial intima-media thickness, a less recognized parameter of cardiovascular risk, is independently associated with coronary artery disease. The aim of this study was to evaluate the prognostic value of ultrasound and serologic parameters of endothelial function in relation to cardiovascular mortality in peripheral arterial disease.

Design: monocentric, prospective cohort study.

Methods: Flow mediated dilatation and brachial intima-media thickness were assessed in 184 (124 male) patients with peripheral arterial disease (Rutherford stages 2-3). Serologic parameters of endothelial function included asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and L-homoarginine. Cardiovascular events were recorded during a follow-up of 99.1±11.1 months. Subjects who died of noncardiovascular causes were excluded from further analysis.

Results: Eighty-two patients (44.6%) died during follow-up after a mean duration of 49.7±28.3 months. There were 49 cardiovascular deaths (59.8%) and 33 other deaths (40.2%). Flow mediated dilatation was associated with cardiovascular death [1.17% (0.0, 4.3) vs. 4.1% (1.2, 6.4), p<0.001]. Intima-media thickness was greater in patients who succumbed to cardiovascular disease [0.37 mm (0.30, 0.41)] than in survivors [0.21 mm (0.15, 0.38), p<0.001]. Brachial intima-media thickness above 0.345 mm was most predictive of cardiovascular death, with sensitivity and specificity values of 0.714 and 0.657, respectively (p<0.001). Furthermore, ADMA levels above 0.745 µmol/l and SDMA levels above 0.825 µmol/l were significantly associated with cardiovascular death (p<0.001 and 0.030).

Conclusion: In symptomatic peripheral arterial disease, decreased flow mediated dilatation, enlarged intima-media thickness, and elevated levels of ADMA and SDMA were associated with increased cardiovascular risk.

Figure 1. Grey scale ultrasound image of the right brachial artery of a 74-year-old female patient.

Brachial IMT is measured three times in a one-centimeter-long segment. ECG triggering indicates the measurement in the enddiastolic phase.

Figure 2. Cox regression survival plots showing cardiovascular mortality as a function of FMD, B-IMT, ADMA and SDMA with adjustment for age, gender, arterial hypertension, smoking behavior, and creatinine clearance.