Clinical Significance Of Ultrasound Screening For Abdominal Aortic Aneurysm In Patients With Coronary Artery Disease

BackgroundsAbdominal aortic aneurysm(AAA)is a life-threatening disease without obvious symptom at early stage.Once it progressed to rupture,the mortality was up to 80%.Four large randomized controlled trials(RCTs),with AAA prevalence rates of 4-7.2%,demonstrated that screening for AAA in elderly men would reduce AAA specific mortality by 40%during the 3 to 5-year follow up period.Due to the benefit of AAA screening,it is recommended in the 2014 ESC guidelines on the diagnosis and treatment of aortic diseases,that population screening for AAA with ultrasound should be performed in all men>65 years of age(Class I,Level A).Abdominal aortic ultrasound is a standard method for AAA screening,with high sensitivity(94%-100%)and specificity(98%-100%).However,the majority evidences for guidelines were based on the Caucasian population.Some studies demonstrated that the prevalence of AAA of Asian origin may be lower than other racial groups.The clinical significance of screening for AAA in these population was lack of evaluation.As the cost-effectiveness of screening AAA is affected by disease prevalence,we sought to evaluate a specific population with the potential for higher detection rates of AAA.Epidemiologic screening studies have demonstrated a higher prevalence of AAA in patients with coronary artery disease(CAD)than others without.A meta-analysis demonstrated that the prevalence of AAA is approximately 2.4 times higher among patients with a history of CAD compared with the general population without CAD.However,it is lack of studies concerning the prevalence of AAA in Chinese patients with CAD.We assumed that there may be a higher prevalence of AAA in Chinese patients with CAD.PurposeThe purpose of the study was to determine the prevalence of AAA with abdominal aortic ultrasound and to explore the predictors of AAA in Chinese patients with CAD in order to evaluate a specific population with the potential for higher detection rates of AAA.MethodsFrom October 2014 to June 2015,a prospective observational study was conducted in the department of cardiology at Guangdong General Hospital.Screening for AAA by abdominal aortic ultrasound were performed in 1271 consecutive patients with angiography-verified CAD.Demographic data,results of coronary artery angiography,abdominal aortic ultrasound and transthoracic echocardiography were collected prospectively.The prevalence of AAA in Chinese patients with CAD was evaluated and independent predictors of AAA were analyzed by logistic regression model.ResultsBecause of obesity or intestinal gas leading to inadequate quality of the abdominal aortic ultrasound images,31(2.4%)patients were excluded from the study.The analysis was based on the 1240(97.6%)patients whose abdominal aortic ultrasound images were feasible.In 1240 patients with CAD,21 patients were newly diagnosed with AAA,3 patients reported a history of AAA.Thus,yielding a prevalence of 1.9%(24/1240).The prevalence of AAA was 3.1%(13/422)in male patients with CAD aged over 65 years.In multivariate analysis,age≥65 years(OR=2.55;95%CI=1.04-6.26;P=0.041),smoking(OR=3.04;95%CI=1.18-7.82;P = 0.021),hypertension(OR =3.32;95%CI=1.10-9.96;P=0.033),aortic root diameter>30mm(OR =3.32;95%CI =1.44-7.67;P=0.005)were independent predictors of AAA.The prevalence of AAA was 0%(0/112)in patients without any independent predictor,0.8%(3/393)in patients with one predictor,1.2%(6/486)in patients with two predictors,5.6%(12/215)in patients with three predictors,and up to 8.8%(3/34)in patients with four predictors.Stepwise increases in the prevalence of AAA were found to depend on the number of independent predictors(P<0.001;P-value for trend<0.001).ConclusionsThe prevalence of AAA in Chinese patients with CAD may be lower than Caucasians.Age ≥65 years,smoking,hypertension and aortic root diameter>30mm emerged as independent predictors of AAA.Stepwise increases in the prevalence of AAA were found to depend on the number of independent predictors.Ultrasound screening for AAA in patients with CAD could be considered in these high risk patients,especially those with three or four predictors.