Faculty Bibliography

OBJECTIVEThe aim of this study was to investigate the relationship between diabetes and different phenotypes of peripheral vascular disease (lower extremity peripheral artery disease [PAD], carotid artery stenosis [CAS], and abdominal aortic aneurysm [AAA]).RESEARCH DESIGN AND METHODSPrevalence of vascular disease was evaluated in 3,696,778 participants of the Life Line Screening survey between 2003 and 2008. PAD was defined as ankle-brachial pressure index <0.90 or prior revascularization, CAS as >/=50% stenosis or prior revascularization, and AAA as infrarenal aortic diameter >/=3 cm or prior repair. Odds ratios (ORs) and 95% CIs were assessed using logistic regression modeling.RESULTSDiabetes mellitus was present in 10.8% of participants (n = 399,884). Prevalence of PAD, CAS, and AAA were significantly higher (P < 0.0001) in participants with compared with those without diabetes. After multivariate adjustment for baseline demographics and clinical risk factors, a significant interaction existed between diabetes and vascular disease phenotype (P < 0.0001). Diabetes was associated with increased odds of PAD (OR 1.42 [95% CI 1.41-1.4]; P < 0.0001) and CAS (1.45 [1.43-1.47]; P < 0.0001) but decreased odds of AAA (0.86 [0.84-0.88]; P < 0.0001). The strength of association increased with increasing severity of disease in each vascular phenotype, and this association persisted in the population with asymptomatic vascular disease.CONCLUSIONSIn a large population-based study, the association between diabetes and vascular disease differed according to vascular phenotype. Future studies exploring the mechanism for these vascular-specific differences are needed.

BACKGROUND: Ankle-brachial index (ABI) testing is a simple, noninvasive method to diagnose peripheral artery disease (PAD) and is associated with all-cause mortality. The association of ABI levels and myocardial infarction (MI) and stroke is less certain. We sought to further characterize the association between ABI levels and history of MI and stroke. METHODS: Using data from the Life Line Screening program, 3.6 million self-referred participants from 2003 to 2008 completed a medical questionnaire and had bilateral ABIs performed. Logistic regression was used to estimate the association between ABI cutoff points (ABI <0.90 and ABI >1.40) and ABI levels with history of MI, stroke, and MI or stroke (MI/stroke). Models were adjusted for age, sex, race/ethnicity, smoking, diabetes, hypertension, hypercholesterolemia, physical activity, and family history of cardiovascular disease. Separate sex-specific models were performed. RESULTS: Overall, 155,552 (4.5%) had an ABI <0.90, and 42,890 (1.2%) had an ABI >1.40. An ABI <0.90 was associated with higher odds of MI (adjusted odds ratio [OR] 1.67, 95% CI 1.63-1.71), stroke (OR 1.77, 95% CI 1.72-1.82), and MI/stroke (OR 1.71, 95% CI 1.67-1.74), all P < .001. An ABI >1.40 was also associated with higher odds of MI (OR 1.19, 95% CI 1.14-1.24), stroke (OR 1.30, 95% CI 1.22-1.38), and MI/stroke (OR 1.22, 95% CI 1.17-1.27), all P < .001. The ORs for MI/stroke for different ABI levels formed a reverse J-shaped curve in both women and men. CONCLUSIONS: In a large national screening database, there is a strong, consistent relationship between ABI levels and a history of prevalent MI, stroke, and MI/stroke.

BACKGROUND: The incidence of concomitant carotid artery stenosis and unruptured intracranial aneurysms (UIAs) has been reported at between 0.5% and 5%. In these patients, treatment strategies must balance the risk of ischemic stroke with the risk of aneurysmal rupture. Several studies have addressed the natural course of UIAs in the setting of carotid revascularization; however, the final recommendations are not uniform. The purpose of this study was to review our institutional experience with concomitant UIAs and carotid artery stenosis. METHODS: We performed a retrospective review of all patients with carotid artery stenosis who underwent carotid artery endarterectomy (CEA) or carotid artery stenting (CAS) at our institution between 2003 and 2010. Only patients with preoperative imaging demonstrating intracranial circulation were included. Charts were reviewed for patients' demographic and clinical data, duration of follow-up, and aneurysm size and location. Patients were stratified into 2 groups: carotid artery stenosis with unruptured intracranial aneurysm (CS/UIA) and carotid artery stenosis without intracranial aneurysm (CS). RESULTS: Three hundred five patients met the inclusion criteria and had a total of 316 carotid procedures (CAS or CEA) performed. Eleven patients were found to have UIAs (3.61%) prior to carotid revascularization. Male and female prevalence was 2.59% and 5.26% (P = 0.22), respectively. Patients' demographics did not differ significantly between the 2 groups. The average aneurysm size was 3.25 +/- 2.13 mm, and the most common location was the cavernous segment of the internal carotid artery. No patient in the study had aneurysm rupture, and the mean follow-up time was 26.5 months for the CS/UIA group. CONCLUSIONS: Concomitant carotid artery stenosis and UIAs is a rare entity. Carotid revascularization does not appear to increase the risk of rupture for small aneurysms (<10 mm) in the midterm. Although not statistically significant, there was a higher incidence of aneurysms found in females in our patient population.

BACKGROUND: The precise relationship between risk factor burden and prevalence of peripheral artery disease (PAD) in different vascular territories (PAD, carotid artery stenosis [CAS], and abdominal aortic aneurysms [AAAs]) is unclear. METHODS: We investigated the association of modifiable risk factors (hypertension, hypercholesterolemia, smoking, diabetes, and sedentary lifestyle) with any and type-specific peripheral vascular disease (PVD) among 3.3 million patients in the U.S., aged 40 to 99, who underwent screening bilateral ankle brachial indices, carotid duplex ultrasound, and abdominal aortic ultrasound in the Life Line Screening program between 2004 and 2008. Multivariate logistic regression analysis was used to estimate the odds of disease in different risk factor categories. Population-attributable risk was calculated to estimate the proportion of disease that could be potentially ascribed to modifiable risk factors. RESULTS: Among 3,319,993 participants, prevalence of any PVD was 7.51% (95% confidence interval [CI], 7.50%-7.53%). PAD was present in 3.56% (95% CI, 3.54%-3.58%), CAS in 3.94% (95% CI, 3.92%-3.96%), and AAAs in 0.88% (95% CI, 0.86%-0.89%). The multivariate-adjusted prevalence with the presence of 0, 1, 2, 3, 4, and 5 modifiable risk factors was 2.76, 4.63, 7.12, 10.73, 16.00, and 22.08 (P < .0001 for trend) for any PVD; 1.18, 2.09, 3.28, 5.14, 8.32, and 12.43 (P < .0001 for trend) for PAD; 1.41, 2.36, 3.72, 5.73, 8.48, and 11.58 (P < .0001 for trend) for CAS; and 0.31, 0.54, 0.85, 1.28, 1.82, and 2.39 (P < .0001 for trend) for AAAs, respectively. These associations were similar for men and women. For every additional modifiable risk factor that was present, the multivariate-adjusted odds of having vascular disease increased significantly (any PVD [odds ratio (OR), 1.58; 95% CI, 1.58-1.59]; PAD [OR, 1.62; 95% CI, 1.62-1.63]; CAS [OR, 1.57; 95% CI, 1.56-1.57]; and AAA [OR, 1.51; 95% CI, 1.50-1.53]). CONCLUSION: This very large contemporary database demonstrates that risk factor burden is associated with an increased prevalence of PVD, and there is a graded association between the number of risk factors present and the prevalence of PAD, CAS, and AAAs.

OBJECTIVE: : To develop a model for the identification of individuals at risk for carotid stenosis (CS) that could be useful in a clinical setting when trying to decide whether screening is worthwhile. BACKGROUND: : Evidence that aggressive medical therapy and life style changes reduce the risk of stroke in individuals with CS is increasing and has led to a renewed interest in screening for CS. METHODS: : Data on demographics and risk factors were obtained from 2,885,257 individuals who had carotid Duplex scans by Life Line Screening between 2003 and 2008. Multivariable logistic regression analysis was used to identify independent risk factors for CS (>50% stenosis). A scoring system was developed where risk factors were assigned a weighted score. Predictive ability was assessed by calculating C statistics and r. RESULTS: : In the screened cohort, 71,004 patients (2.4%) had CS. Independent risk factors include advanced age, smoking, peripheral arterial disease, high blood pressure, coronary artery disease, diabetes, cholesterol, and abdominal aortic aneurysm. African Americans, Asians, and Hispanics had reduced risk than whites. Exercise and consumption of fruit, vegetables, and nuts had a modest protective effect. A predictive scoring system was created that identifies individuals with CS more efficiently (C statistic = 0.753) than previously published models. CONCLUSIONS: : We provide a model that enables identification of individuals who have a high probability of having CS. This model can be helpful in designing targeted screening programs that are cost-effective.

OBJECTIVE: This study sought to determine the relationship between vascular disease in different arterial territories and advanced age. BACKGROUND: Vascular disease in the peripheral circulation is associated with significant morbidity and mortality. There is little data to assess the prevalence of different phenotypes of vascular disease in the very elderly. METHODS: Over 3.6 million self-referred participants from 2003-2008 who completed a medical and lifestyle questionnaire in the United States were evaluated by screening ankle brachial indices <0.9 for peripheral artery disease (PAD), and ultrasound imaging for carotid artery stenosis (CAS) >50% and abdominal aortic aneurysm (AAA) >3cm. Participants were stratified by decade of life. Multivariate logistic regression analysis was used to estimate odds of disease in different age categories. RESULTS: Overall, the prevalence of PAD, CAS, and AAA, was 3.7%, 3.9%, and 0.9%, respectively. Prevalence of any vascular disease increased with age (40-50y: 2%; 51-60y: 3.5%; 61-70y: 7.1%; 71-80y: 13.0%; 81-90y: 22.3%; 91-100y: 32.5%; P<0.0001). Prevalence of disease in each vascular territory increased with age. After adjustment for sex, race/ethnicity, body mass index, family history of cardiovascular disease, smoking, diabetes, hypertension, hypercholesterolemia, and exercise, the odds of PAD (OR 2.14, 95% CI 2.12-2.15), CAS (OR 1.80, 95% CI 1.79-1.81), and AAA (OR 2.33, 95% CI 2.30-2.36]) increased with every decade of life. CONCLUSION: There is a dramatic increase in the prevalence of PAD, CAS, and AAA with advanced age. More than 20% and 30% of octo- and nonagenarians, respectively, have vascular disease in at least 1 arterial territory.