Ischemia-modified albumin and NT-prohormone-brain natriuretic peptide in peripheral arterial disease

Cardiovascular disease is the leading cause of mortality and morbidity in Western countries. Despite its remarkable medical and social consequences, the prevalence of peripheral arterial disease (PAD) is often underestimated among atherosclerotic disorders. So far, little is known about the behavior of traditional and emerging markers of ischemic heart disease that should allow the reliable identification of PAD patients at increased risk of developing myocardial ischemia and heart failure or dysfunction. To investigate this topic, we measured cardiac troponin T (cTnT), ischemia-modified albumin (IMA) and NT-prohormone-brain natriuretic peptide (NT-proBNP) in 35 consecutive patients with clinically ascertained PAD (stage 2-4, according to Lériche-Fontaine) asymptomatic for chest pain and current heart failure, and 20 controls displaying moderate to high cardiovascular risk factors (hypertension, diabetes, hyperlipidemia), but with no clinical evidence of PAD. Although the concentrations of cTnT and IMA were not statistically increased in PAD patients, NT-pro-BNP values were substantially higher in PAD patients than in controls (62.6 vs. 7.4 pmol/L, p<0.0001). The percentage of subjects displaying values exceeding the specific NT-proBNP diagnostic threshold (>14.8 pmol/L) was also significantly different between PAD patients and controls (74% vs. 10%, p<0.001). After excluding PAD patients exceeding the 0.01 ng/mL cTnT cutoff value indicative of current ischemic cardiac involvement, the median concentration of NT-proBNP remained statistically increased (28.0 vs. 5.8 pmol/L, p<0.0001). Taken together, these results indicate that NT-proBNP, but not IMA, is substantially increased in PAD patients. This finding suggests that such patients, even though asymptomatic, might develop myocardial dysfunction, and thus warrant further investigation.