The Study Of Diagnostic Value Of Toe Brachial Index (TBI) In Diabetic Patient With Lower Extremity Arterial Disease In Early Stage And The Risk Factors For Lower Extremity Arterial Disease

Diabetic foot (DF) is a serious complication of diabetes mullitus (DM),and is also the leading cause of non-traumatic amputation in developedcountries. Lower Extremity Arterial Disease (LEAD) with diabetes is animportant factor of wound with diabetic foot healing. Diagnosis andtreatment of LEAD in early stage is significant for the prevention of DFand amputation. Toe-brachial index(TBI) was recorded as the ratio of toesystolic biood pressure to the bracnial arterial systolic blood pressure andcan reflect the situation of lower limb artery stenosis. At present TBI isrecommended when Aoe brachial Index(ABI) increased negatively, as toearteries are generally unaffected by calcification. TBI<0.7is the diagnosticcriteria for LEAD. LEAD with DM was present in artery of blow knee，TBIcould reflect the situation of more distal arteries. The guidelines werefocusing on measuing TBI as abnormal increased ABI， while the reportedin the literature for measuing TBI in patients witn normal ABI was less.Thestudy was to investigate the diagnostic value of TBI for screening forLEAD with DM, and analyze the risk factors for TBI, and then provide theclinical evidence for diagnosis and treatment of LEAD in early stage andprevention of DF. Many X-ray date from patients with DF dispaly thepresence of calcification in dorsal metatarsal arteries which was moresignificantly than toe arteries in clinical. All the evidences for foot vascularcalcification were from indirect evidences of X-ray. Preliminarily the studywas to investigate the diagnostic value of TBI for diagnosing LEAD bydirect evidence of pathological. 265(male171, famale94) inpatients with type2diabetes wereenrolled from January2013to August2013in endocrinology department ofGeneral Hospital of Air Force, the clinical data which include age, gender,duration of diabetes, body mass index (BMI), smoking, complication(hypertension, coronery heart disease, cerebrovascular disease, DF),glycosylated hemoglobin(HbA1c), high density lipoprotein cholesterol(HDL-c), Low-density lipoprotein cholesterol (LDL-c), totalcholesterol(TC), triglycerides(TG), fibrinogen (FIB), and neckultrasonography were collected to do a statistic analusis in the study. Thosewere divided into low TBI (TBI＜0.7,127case, L-TBI) group and normalTBI(TBI≥0.7,137case, N-TBI) group according to the TBI＜0.7, thenclinical data were compared between the two groups, the risk factor for TBIwere screened by logistic multiple regression analysis.The diagnostic indicator of TBI (sensitivity, specificity, positivepredictive value, negative predictive value, positive likelihood ratio,negative likelihood ratio) were evaluated by diagnostic test with ABI≤0.9for the LEAD diagnostic standard, the agreement of TBI and ABI wasevaluated by using kappa test.Clinical data of195inpatients with DF were collected, toe arteriesamputation operation was performed in43patients, and the abandoned toearteries were staining by Van Kossa staining to observe calcification in toearteries. According to the calcification resunts divided into three groups:group non calcification (A group), group dorsal metatarsal arteriescalcification(B group), group toe arteries calcification (C group), clinicaldata from the three groups were analyzed.The results in the study included1. The morbidity of LEAD was19.44%.2. Comparison of the clinical date between the two groups showedthat age and FIB were significantly higher and duration of DM were longerand the complications including hypertension, coronery heart disease,cerebrovascular disease, DF, carotid artery intima-medial thickening (CAIMT), carotid artery plaque formation (CAPF) and carotid arterystenosis (CAS) were more in group L-TBI, the difference was statisticallysignificant (P＜0.05). The standard reaching rate of LDL-c, TC, TG washigher in group L-TBI, the difference was statistically significant (P＜0.05).3. The date from correlation analysis showed that a negative correlationbetween TBI and age (r=-0.364, P＜0.001), duration of DM (r=-0.363,P=0.027), CAIMT (r=-0.182, P=0.007), CAPF(r=-0.277, P＜0.001) andCAS(r=-0.239,P＜0.001), and a positive correlation between TBI andtandard reaching rate of TC(r=0.139,P=0.027) and LDL-c (r=0.116,P=0.066).4. Logistic multiple regression analysis revealed that age(＞60years), duration of DM(≥20years) and FIB(＞4.1g/l) were risk factorsfor TBI, OR and95%CI respectively were (3.097,1.54-6.23),(2.251,1.03-4.91),(2.068,1.09-3.94).5. There were28.5%ABI normal but TBIlower in the study.6. The kappa value was0.334（95%CI0.256～0.412）representing having a fair agreement of the two method.7. Diagnosticindicator of TBI were sensitivity81.8%, specificity71.5%, positivepredictive value33.5%, negative predictive value93.2%, positivelikelihood ratio2.87, negative likelihood ratios0.25.8. X-ray results:91cases had the presence of calcification, the rate of calcification reached to46.6%, calcification of dorsal metatarsal artery was observed in64case(rate32.8%), calcification of dorsal metatarsal artery and toe arterywas observed in25case(12.8%), calcification of toe artery was observed in2case(1.0%).9. Result from histology: there were33patients withoutcalcification,9patients with mild to moderate calcification and2patientswith severe calcification from evidence of toe artery in43patient.10.Duration of DM was longer in group calcification, the difference wasstatistically significant (P＜0.05).The conclusion in the study included1. TBI is a sensitive index fordiagnosis and screening of LEAD in early stage.2. Age, duration ofdiabetes and FIB are risk factors for TBI.3. Except ABI, TBI should be measured to screen for LEAD in the patients whose age older60yearsand/or duration of DM longer5years.