Doppler Screening Of Carotid Artery Stenosis In Patients With Peripheral Atherosclerotic Occlusive Disease

PART I THE CORRELATION BETWEEN THE SEVERITY OF PERIPHERAL ARTERIAL DISEASE AND CAROTID OCCLUSIVE DISEASEObjective:Peripheral arterial disease(PAD)and carotid occlusive disease(COD)are both known to be specific manifestations of atherosclerosis.Because they both have a common cause,it is reasonable to hypothesize that they should correlate with each other to a certain extent,and previous studies have shown that there is a correlation between the prevalence of PAD and COD.The purpose of this study was to determine whether a correlation exists between the severity of PAD and the severity of CODMethods: 203 patients were retrospectively looking at a group of who underwent non-invasive testing for suspicion of PAD at our hospital,and who also had a non-invasive duplex carotid scan.The severity of PAD was assessed by segmental blood pressure ratios(leg segment/arm ratio)in each leg taken at the toe,ankle,and below the knee,as well as the peak flow velocity of the posterior tibial artery.The severity of COD was assessed by duplex ultrasound scans of six distinct segments of the carotid artery system: the right and left common,internal,and external carotid arteries.Results: Correlation analysis showed r = 0.23(p=0.001)when comparing a PAD aggregate standard score with the number of diseased carotid arteries(>50% stenosis),and r = 0.23(p = 0.001)when comparing a PAD aggregate standard score with an average COD score.Because about 50% of the patients had undergone surgical intervention on their leg or carotid arteries,another correlation analysis restricted to patients with no surgical interventions(n = 97)was performed.The above correlations were slightly attenuated in this analysis,r = 0.21(p = 0.043)and r = 0.17(p = 0.092),respectively.Conclusions: The results indicate that there is a modest but significant correlation between the severity of PAD and the severity of COD in a population with a high prevalence of both.PART II PREVALENCE OF ASYMPTOMATIC CRITICAL CAROTID ARTERY STENOSIS IN PATIENTS WITH CHRONIC ATHEROSCLEROTIC LOWER EXTREMITY ISCHEMIAObjective: This study aimed to investigate prevalence of asymptomatic carotid artery stenosis(ACAS)in Korean patients with peripheral arterial disease(PAD)and identify predictive factors of ACAS in patients with PAD.Methods: Between 1994 and 2008,546 patients who underwent bypass surgery due to PAD were identified in a single tertiary teaching hospital.Of those,409 patients underwent preoperative screening carotid duplex ultrasonography(CDUS).Patients who had an episode of cerebrovascular event or previous carotid artery intervention were excluded and then a retrospective analysis was made of 340 patients.The degree of internal carotid artery(ICA)stenosis was determined by the criteria of Society of Radiologists in Ultrasound Consensus Conference.To determine the risk factors of ACAS,demographic,coexisting medical condition and lesion characteristics were tested with binary logistic regression model.Results: The prevalence of ?70% ICA stenosis was 14%.ICA occlusion was detected in 7.1%.Multivariate analysis revealed age >65 yr(OR: 2.610,95% CI: 1.197-5.691)and coronary artery disease(CAD,OR: 2.333,95% CI: 1.169-4.657)are predictive factors of ?70% stenosis.Conclusions: A PAD patient who needs revascularization,particularly,>65 yr or has a concomitant CAD,can be a good candidate of screening CDUS.PART III PREVALENCE OF CAROTID STENOSIS AND SILENT MYOCARDIAL ISCHEMIA IN ASYMPTOMATIC SUBJECTS WITH A LOW ANKLE-BRACHIAL INDEXObjective: Subjects with symptomatic peripheral artery disease(PAD)have an elevated prevalence of carotid stenosis and of silent myocardial ischaemia.As such,clinical guidelines advocate the detection of sub-clinical vascular disease in this population.However,the prevalence of occult vascular disease in asymptomatic patients with a low anklebrachial index(ABI)has not been previously evaluated.Methods: Cross-sectional study in five primary care centres for patients' selection and two University Hospitals for further assessment.Subjects were 1070 asymptomatic individuals between 60 and 80 years of age with at least two cardiovascular risk factors,selected for ankle-brachial index measurement.Eighty five subjects with an ABI <0.9 and an equal number of controls,matched for age,gender,diabetes,and smoking habit,and with a normal ABI,were referred to the Hospital for carotid ultrasound and exercise stress tests(EST).Main outcome measures were prevalence of a carotid stenosis >50% and an abnormal EST.Results: The prevalence of a low ABI in the overall population was 9.1%.A carotid stenosis >50% was detected in 14.3% of the subjects with a low ABI and in 4.7% of the control subjects(Odds Ratio [OR]: 3.37;95% Confidence Interval [CI]: 1.04-10.93,P =.033).The prevalence of a positive EST test was 16.2% in those with a low ABI and 10.5% in control subjects(OR: 1.65;95% CI: 0.63-4.29,P =.309).These prevalences were higher in older subjects,in those with hypertension or diabetes,or in those with dyslipidemia.Conclusion: Our results indicate that in high-risk asymptomatic subjects >60 years of age,the presence of an ABI <0.9 identifies a subgroup of the population with an increased prevalence of carotid stenosis and of silent myocardial ischemia and,as such,are candidates for closer follow-up.