The Predictive Value Of Resting And Exercise Ankle-brachial Index In Coronary Artery Stenosis

Objective:To compare the resting ankle-brachial index (ABI) and ABI after exercise in prediting coronary artery stenosis.Methods:One huandred and twenty patients were divided into three groups according to coronary angiography:normal coronary artery group, mild to moderate stenosis group, severe stenosis group. Resting ABI and ABI after exercise were measured in each patients. Gensini scores were estimated based on angiography. Correlations between ABI and Gensini scores were calculated. Receiver's operating characteristic curve (ROC) analysis was used to compare the utility of resting and exercise ABI in predicting of coronary artery stenosis.Results:1. Resting ABI was significantly lower in severe stenosis group (0.93±0.11) than rest ABIs in normal group (1.051:0.11, p<0.05) and mild stenosis group (1.02±0.16, p<0.05). Exercise ABI was significantly lower in sever stenosis group (0.86±0.13) than that in normal group (1.07±0.14, p<0.05) and mild stenosis group (1.02±0.11,p<0.05).2. Gensini scores were significantly correlated with resting ABI (r=-0.55, p<0.001) and exercise ABI (r=-0.89, p<0.001).3. Areas under curves of ROC were 0.646 for resting ABI (p=0.033) and 0.752 for exrcise ABI (p<0.001) respectively and no significant difference was found between these two areas. The sensitivity and specificity were 36.6%and 86.4%for resting ABI and 52.36%and 86.36%for exercise ABI if the ABI cutoff point was set to be≤=0.9. The sensitivity and specificity were 62.7%and 68.2%for resting ABI and 69.3%and 77.3%for exercise ABI if the ABI cutoff point was≤1.4. Areas under curves of resting ABI were 0.61 (P= 0.079) in the mild stenosis group and 0.764 (P<0.001) in severe stenosis group. Areas under curves of exercise ABI were 0.58 (P-0.296) in the mild stenosis group and 0.919 (P<0.001) in severe stenosis group. These results indicated that Both resting and exercise ABI can identify patients with severe stenosis. But exerciseABI was better than resting ABI (p<0.001) in identifying patients with sever stenosis.Conclusion:1. Both resting and exercise ABI are correlated with extent of coronary artery stenosis but exercise ABI has stronger correlation with stenosis than resting ABI does2. Exercise ABI is superior to resting in predicting sever coronary artery stenosis.