| BackgroundPeripheral atherosclerotic disease (PAD) is an important mark for systematic atherosclerosis, currently considered an equivalent to coronary heart disease. It is closely related with cardiovascular and cerebrovascular events. With the prevention and early treatment of atherosclerotic disease being emphasized clinically, the early diagnosis and management of atherosclerotic lesions of the lower extremity is important for preventing and treating PAD and mitigating systematic atherosclerotic lesions. So far, there is not ideal diagnosis method for diagnosing the early lesion of PAD. Exercise treadmill testing(ETT), as a sensitive tool to assess vascular reaction to workload in a dynamic, objective manner, may play an important role for diagnosing hemodynamic arteriostenosis, such as the early atherosclerotic lesion.ObjectiveThis study was to observe the lesion of atherosclerotic and arteriosclerosis in high-risk population for PAD and with their ABI value higher than or equal to 0.9, in additions, we prospectively evaluate the diagnostic value of ABI binding exercise treadmill testing (ETT) in assessing early atherosclerotic lesions of the lower extremity in this population.Methods1. A randomly enrolled cohort,331 high-risk patients for PAD with ABI value higher than or equal to 0.9, underwent simultaneously ABI testing and low extremity arterial duplex ultrasound within one week. According to the ABI value, they were divided into four groups:Borderline lower value (ABI:0.91～0.99), Borderline midvalue(ABI:1.0～1.09), Borderline higher value (ABI:1.1～1.29) and higher value group (ABI≥1.3). The manifestation of lower extremity atherosclerosis were determined based on the results of low extremity artery duplex ultrasound.2. A randomly enrolled cohort,173 high-risk patients for PAD with ABI value higher than or equal to 1.0, underwent simultaneously ABI testing、brachial artery pulse wave velocity (baPWV)、up aorta PWV and low extremity arterial duplex ultrasound within one week. According to the result of lower extremity atherosclerosis, they were divided into different group, and were analysised their arteriosclerosis variability among those groups by the way of Analysis of Variance (ANOVA).3. A randomly enrolled cohort,33 health patients and 236 high-risk patients for PAD, underwent simultaneously ETT (Bruce’s proposal)、ABI test and low extremity arterial duplex ultrasound within one week. According to the change of ABI value at 1 min after ETT, they were divided into ABI descending greater than or equal to 20 per cent, ABI descending lower than 20 per cent and ABI elevating group. The normal population as control, we analyzed and compared the other three groups of risk factors, the hemodynamic changes after EET and the manifestation of lower extremity arterial atherosclerosis lesions.4. A randomly enrolled cohort,173 high-risk patients for PAD, underwent simultaneously ETT (Bruce’s proposal、ABI test and low extremity arterial duplex ultrasound within one week. The result of lower extremity arterial duplex as the diagnostic criteria, we analysized the sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of ABI exercise test diagnosing the early atherosclerotic lesions in lower extremity, and assessed the clinical diagnostic value of ETT in diagnosing early atherosclerotic lesions of lower extremity by Receiver operator characteristics (ROC) analysis.Results1. Of 331 high-risk patients for PAD with ABI value higher than or equal to 0.9, 57.7% have different degrees of atherosclerosis in lower extremity artery. The atherosclerotic lesions of low extremities in Borderline lower value group mainly displayed large plaques causing reduction in luminal diameter (Ⅲgrade andⅣgrade of atherosclerosis,67.7%), while those in higher value group were mainly displayed as diffuse dot-like hyperechogenicity spots(Ⅱgrade,43.8%), furthermore, the incidence of intima-media thickness (IMT) in both groups were all significantly higher than other group (p<0.05);2. In Borderline lower value, Borderline midvalue and Borderline higher value group, the atherosclerotic lesions all predominantly involved in the proximal segments of lower extremity artery (84.2%,78.6%2及79.7%), while, in higher value group, the atherosclerotic lesions predominantly involved in the distal segment of the lower extremity artery (57.1%);3. There were no statistically significant differences on indictors such as baPWV, haPWV, pulse pressor and ankle pressor between patients with and without low limb artery intima-media thickness increasing (p>0.05)4. Compared with no pathological changes group, the values of baPWV and haPWV in diffused pathological group and that in little atherosclerosis plaque group significantly increased (p<0.05),the values of pulse pressor of little atherosclerosis plaque group significantly increased (p<0.05), however, there were no statistically significant differences on indictors of arteries stiffness in large atherosclerosis plaque group (p>0.05);5. After high-risk patients for PAD having undwent ABI exercise test, the ABI change showed ABI decreased up and equal to 20%(≥20%), lower than 20%(<20%) and elevated. The ankle pressure continued to decrease in patients with ABI declined≥20% after exercise lmin to 10min. The atherosclerotic lesion in this group was the most serious, mainly displayed large plaques (area> 20mm2) causing reduction in luminal diameter. While, the ABI value and ankle pressure in patients with ABI elevated were all increased at 1 min after exercise, and ABI value continued to increase, the atherosclerotic lesion in this group mainly displayed diffuse dot-like hyperechogenicity lesion (60.0%), whereas, the atherosclerotic lesion in ABI declined <20% group mainly displayed IMT (55.6%);6. After exercise, ABI decreased in all patients. The more severe the atherosclerotic lesions of the lower extremity were, the larger the ABI decrement after exercise was. Ultrasonography was used as the standard in defining atherosclerotic lesions such as large, small plaques, and diffuse spotty atherosclerotic lesions, the respective areas under the ROC curve were 0.802 (95%CI,0.722,0.882),0.78 (95%CI,0.708,0.852), and 0.599 (95%CI,0.44,0.757);7. Using the presence of large atherosclerotic plaques in lower extremities as positive diagnosis, R value was 0.8, with a sensitivity of 54.0%, a specificity of 96.7%, a LR+ of 16.4, and a LR- of 0.58, meanwhile, R value was 0.85, with a sensitivity of 70.0%, a specificity of 91.9%, a LR+ of 8.64, and a LR- of 0.33;8. Of the 173 high-risk patients for PAD, the ETT result was positive in 31 patients (17.9% of the total population), among those, there were 15 cases of no previous diagnosis of coronary heart disease (8.6% of the total population, accounting for 48.4% of positive patients). while, the ETT result was suspected positive in 24 cases(13.9% of the total population), among those, there were 17 cases of no previous diagnosis of coronary heart disease (9.8% of the total population, accounting for 70.8% of suspected positive patients). Ventricular arrhythmia occurred in 6 patients (3.5%):one had paroxysmal ventricular tachycardia (0.6%), which disappeared after oxygen inhalation and sublingual administration of nitroglycerin, and the others had ventricular premature beats, i.e, bigeminy (2.9%).Conclusions1.57.7% of high-risk patients for PAD with ABI value higher than or equal to 0.9 have different degrees of atherosclerosis in lower extremity artery. Among those, the atherosclerotic lesion in Borderline lower value and High value groupp were the most serious. The atherosclerotic lesions of low extremities in Borderline lower value group mainly displayed large plaques (ⅢandⅣgrade lesion,67.7%), and predominantly involved in the proximal segments of lower extremity artery. Besides, the risk facotrs of patients mainly was atherosclerotic risk factors and the major atherosclerotic basis. However, The atherosclerotic lesions of low extremities in High value group mainly displayed as diffuse dot-like hyperechogenicity spots(II grade), and predominantly involved in the distal segment of the lower extremity artery. In additons, the risk factors in this group mainly was systemic atherosclerotic vascular disease risk factors. These findings suggest that the clinician should think highly of the patient with Borderline lower value and High value group, and positively take different prophylactic measures in time according to different risk factor and different pathological changes.2. No statistically significant differences on indictors such as baPWV, haPWV, pulse pressor and ankle pressor between patients with and without IMT was observed, this founding suggests that the arteriosclerosis index can not define the IMT degree. Divided in the atherosclerotic lesions, the values of baPWV and haPWV in diffused pathological group and that in little atherosclerosis plaque group significantly increased, yet, there were no statistically significant differences in large atherosclerosis plaque group, these founds suggest that the atherosclerosis index increasing contributes to the early atherosclerotic lesions (such as diffuse disease or small plaque), but to heavier early atherosclerotic lesions, its predictive value was very low. These findings suggest that the clinician should not ignor the patients with the normal indicators of atherosclerosis, make a comprehensive and science evaluation combinating with risk factors and clinical symptoms.3. The atherosclerotic lesions of high risk for PAD with ABI declined≥20% after exercise was the most serious, mainly deplayed large plaques (area> 20mn2); The atherosclerotic lesions of high risk for PAD with ABI elevated after exercise mainly deplayed the diffuse dot-like hyperechogenicity lesion, which suggests that the patient in this group has high degree of atherosclerosis. Obviously, the ABI exercise test can detect not only the existence of a large lower extremity arterial plaque(area> 20mm2), but also the increased arterial stiffness, these population should be strengthened to improve the arterial elasticity.4. The more severe the atherosclerotic lesions of the lower extremity were, the larger the ABI decrement after exercise was. Respectively, the atherosclerotic lesions such as large, small plaques, and diffuse spotty atherosclerotic lesions, was used as the positive diagnostic criteriam, the result of ROC curve areas showed that the value of ABI exercise test for diagnosing large atherosclerotic plaque lesions of the lower extremity was very high, it can be used as an more accurate and objective tool to detect the early atherosclerotic lesions of the lower extremity. Besides, Immediately after exercise,0.85 is the cut-off R value appropriate for diagnosing large atherosclerotic plaques of the lower limb (area>20mm2). 5. ABI exercise test is a safe, effective tool for detecting early atherosclerotic lesions of the lower limb for high-risk for PAD, in additions, it can simultaneously detect the myocardial ischemia disease. Hence, the ABI exercise test can provide important clinical basis for early detection and timely prevention of systemic atherosclerotic disease occurrence and development. |
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