Application Of Oscillographic Blood Pressure Measurement In Arterial Diseases Of Lower Extremities

Background:Lower extremity artery disease(LEAD)is caused by the formation of atherosclerotic plaque in lower limb,which causes lower extremity artery stenosis and occlusion,and then leads to chronic limb ischemia.At present,LEAD is highly prevalent in whole world and a important predictor for death,myocardial infarction or stroke.However,most PAD patients are not diagnosed because only few of them have symptoms,most patients are diagnosed by decreased ankle-brachial index(ABI of?0.90),a ratio of ankle SBP to brachial SBP.However,in general practice,ABI is made by doppler method(DP-ABI),and the accuracy of DP-ABI for PAD diagnosis has been proved.In recent years,as technical progress,oscillometric method has became a simple method for detecting ABI by four limb BP measurement,as it is simpler and faster.In addition ABI,inter-arm BP difference(IAD)and inter-ankle BP difference(IAND)could be obtained at the same time.Objective:To evaluate the screening value of systolic ankle-brachial index(ABI)and inter-ankle systolic blood pressure difference(IAND)detected with oscillometric method for Lower extremity arterial disease(LEAD),and to explore whether oscillography blood pressure measurement can be used for screening of LEAD.Methods:Continuous enrollment group from April 2018 to December 2018 in the Department of Vascular surgery,Second Affiliated Hospital,Nanchang University.206 inpatients were included,four limb blood pressure(BP)were measured by oscillometric method(OMRON-HEM-7112)for three times with one minute interval,and their average SBP was correspondingly recorded as SBP for each limbs.The general data of patients were recorded,including age,gender,history of hypertension,history of diabetes.All patients underwent computed tomography angiography(CTA)to diagnosing leg artery disease within a certain period of time.The angiographic disease burden was semi-quantitatively scored as 5 classes on the stenosis at any arterial segment: Class 0 : no stenosis,Class 1 : <50% stenosis,Class 2 : from 50-74% stenosis,Class 3: 75%-99% stenosis,and Class 4: complete occlusion.A stenosis ? 50% at least in one leg was used for diagnosis of LEAD.ABI and IAND were calculated by measuring blood pressure of limbs.The OS-ABI were calculated with the following formula: OS-ABI=ankle-SBP/ brachial-SBP.Here,the brachial-SBP is the higher SBP value of two arms,and the ankle-SBP was the lower value.The absolute difference of SBP between two ankles was calculated as sIAND.Based on epidemiological findings,OS-ABI of ?0.9 and sIAND of ?15 mmHg were used as the cutoff values for diagnosis of PAD in leg.Result:1.Among the 206 patients,169 with ABI?0.9 and 104 with sIAND?15mmHg.2.The sensitivity ? specificity and accuracy of ABI?0.9 for diagnosing 50%stenosis were 91.8%?91.7 % and 91.7%.Those for the sIAND?15mmHg were 55.5%?79.2%? 58.3%,respectively.However when patients with unilateral limb lesions,the sensitivity of sIAND increasing to 93.9%.3.When combination of OS-ABI?0.9 and sIAND?15mmHg,The sensitivity ?specificity and accuracy increased to 96.2%?70.8% and 93.2%.Conclusion:1.The OS-ABI from oscillometric method is a useful index for diagnosis of LEAD in leg,IAND has high diagnostic value in unilateral diseases.What's more,Combination ABI?0.9 and sIAND?15mmHg could improve the diagnosis accuracy.As a simple and easy method,oscillography blood pressure method could be used for screening of LEAD.