Faculty Bibliography

Testosterone therapy is recommended for men with symptomatic androgen deficiency and unequivocally low testosterone levels. Although the prevalence of hypogonadism seems relatively constant, studies of prescribing patterns in both the United States and the United Kingdom show a dramatic increase in testosterone prescription in recent years, possibly due to increased marketing and inappropriate therapy. Concurrent with this, there has been growing concern regarding the potential adverse effects of testosterone therapy, particularly its cardiovascular risks. In this review, we present our current understanding of the implications of testosterone deficiency, as well as the conflicting evidence surrounding the cardiovascular effects of testosterone replacement therapy. Although there is a lack of adequate data, based on the current evidence, we conclude that testosterone therapy can be safely considered in men with appropriately diagnosed clinical androgen deficiency and increased cardiovascular risk after a thorough discussion of potential risks and with guideline recommended safety monitoring.

OBJECTIVE: Although the relationship between physical activity and coronary heart disease is well characterized, a paucity of data exists on physical activity and vascular disease in other arterial territories. This study examined the prevalence of peripheral artery disease (PAD) and carotid artery stenosis (CAS) in association with physical activity. APPROACH AND RESULTS: The association between physical activity and vascular disease was examined in >3 million self-referred US participants in the United States from 2003 to 2008 who completed a medical and lifestyle questionnaire in the Life Line screening program. All subjects were evaluated by screening ankle brachial indices <0.90 for PAD and ultrasound imaging for CAS >50%. Multivariable logistic regression modeling was used to estimate odds of disease. Among 3 250 350 subjects, 63% of the population engaged in some leisure time vigorous physical activity. After adjustment for age, sex, race/ethnicity, hypertension, hypercholesterolemia, smoking status, diabetes mellitus, body mass index, and family history of cardiovascular disease, subjects who reported any physical activity had a significantly lower odds of PAD (odds ratio, 0.64; 95% confidence interval, 0.63-0.65) and CAS (odds ratio, 0.80; 95% confidence interval, 0.79-0.81). The association between physical activity with PAD and CAS was robust when stratified by sex, race, and age categories. Physical activity intensity frequency was associated with lower PAD and CAS in a graded manner (P trend <0.0001 for both). Findings seemed unaffected by confounding by comorbidity or indication. CONCLUSIONS: In a large population-based study, higher levels of physical activity were independently associated with lower odds of vascular disease in the lower extremities and carotid arteries.

INTRODUCTION: There is epidemiological evidence that metal contaminants may play a role in the development of atherosclerosis and its complications. Moreover, a recent clinical trial of a metal chelator had a surprisingly positive result in reducing cardiovascular events in a secondary prevention population, strengthening the link between metal exposure and cardiovascular disease (CVD). This is, therefore, an opportune moment to review evidence that exposure to metal pollutants, such as arsenic, lead, cadmium, and mercury, is a significant risk factor for CVD. METHODS: We reviewed the English-speaking medical literature to assess and present the epidemiological evidence that 4 metals having no role in the human body (xenobiotic), mercury, lead, cadmium, and arsenic, have epidemiologic and mechanistic links to atherosclerosis and CVD. Moreover, we briefly review how the results of the Trial to Assess Chelation Therapy (TACT) strengthen the link between atherosclerosis and xenobiotic metal contamination in humans. CONCLUSIONS: There is strong evidence that xenobiotic metal contamination is linked to atherosclerotic disease and is a modifiable risk factor.

Hemostasis is a major concern during the perioperative period. Changes in platelet aggregation and coagulation factors may contribute to the delicate balance between thrombosis and bleeding. We sought to better understand perioperative hemostasis by investigating the changes in platelet aggregation and coagulation factors during the perioperative period. We performed a prospective cohort analysis of 70 subjects undergoing non-emergent orthopedic surgery of the knee (n = 28), hip (n = 35), or spine (n = 7) between August 2011 and November 2011. Plasma was collected preoperatively (T1), 1-h intraoperatively (T2), 1-h (T3), 24-h (T4) and 48-h (T5) postoperatively. Platelet function testing was performed using whole blood impedance aggregometry. Coagulation assays were performed for factor VII, factor VIII, von Willebrand Factor (vWF), and fibrinogen. Of the 70 patients, mean age was 64.1 +/- 9.8 years, 61 % were female, and 74 % were Caucasian. Platelet activity decreased until 1 h postoperatively and then significantly increased above baseline at 24- and 48-h postoperatively. Compared to baseline, coagulation factors decreased intraoperatively. Factor VII activity continued to decrease, while FVIII, vWF, and fibrinogen all increased above baseline postoperatively. The results of our study indicate significant changes in platelet activity and coagulation factors during the perioperative period. Both platelet activity and markers of coagulation decrease during the intraoperative period and then some increase postoperatively. These changes may contribute to the hypercoagulabity and/or bleeding risk that occurs in the perioperative period. Future prospective studies aimed at correlating hemostatic changes with perioperative outcomes are warranted.

BACKGROUND: Platelets are a major contributor to atherothrombosis and may contribute to the heightened risk of perioperative cardiovascular events. We sought to examine changes in platelet activity in subjects undergoing vascular surgery. METHODS: Platelet activity in 18 patients (median age 74, 45% female) undergoing non-emergent open vascular surgery was assessed by light transmission aggregometry in response to saline, epinephrine and adenosine-5 diphosphate (ADP), and by flow cytometric analysis of monocyte-platelet aggregation (MPA). Platelet activity was assessed preoperatively (T1), 1-hour into the operation (T2), 1-hour (T3), 24-hours (T4) and 48-hours post-operatively (T5). Data were compared using the Wilcoxon Signed Ranks Test. Continuous variables are summarized as medians and (interquartile, IQR) ranges. RESULTS: Spontaneous platelet aggregation increased transiently during the surgical period (T1-5.8% [2.4, 10.8], T2-13.5% [9.3, 26.5], T3-7.5% [3.3, 17], T4-10.0% [7.3, 16.3], T5-7.25% [4.5, 29.9], P=0.002). Similar trends in perioperative platelet activity were noted for platelet aggregation in response to epinephrine (P=0.035) and ADP (P=0.036). Using flow cytometry, we found an increase in MPA during the perioperative period (P=0.047), which was most significant between T1 and T3 (P=0.005). CONCLUSIONS: Platelet activity increases significantly during and following open vascular surgery. This data may help explain the pathophysiology of increased thrombotic risk during the perioperative period of vascular surgery.

BACKGROUND: Although N-terminal pro-B-type natriuretic peptide (NT-proBNP) has a strong relationship with incident cardiovascular disease (CVD), few studies have examined whether NT-proBNP adds to risk prediction algorithms, particularly in women. OBJECTIVES: This study sought to evaluate the relationship between NT-proBNP and incident CVD in women. METHODS: Using a prospective case-cohort within the WHI (Women's Health Initiative) observational study, we selected 1,821 incident cases of CVD (746 myocardial infarctions, 754 ischemic strokes, 160 hemorrhagic strokes, and 161 other cardiovascular [CV] deaths) and a randomly selected reference cohort of 1,992 women without CVD at baseline. RESULTS: Median levels of NT-proBNP were higher at study entry among incident cases (120.3 ng/l [interquartile range (IQR): 68.1 to 219.5 ng/l]) than among control subjects (100.4 ng/l [IQR: 59.7 to 172.6 ng/l]; p < 0.0001). Women in the highest quartile of NT-proBNP (>/=140.8 ng/l) were at 53% increased risk of CVD versus those in the lowest quartile after adjusting for traditional risk factors (1.53 [95% confidence interval (CI): 1.21 to 1.94]; p for trend <0.0001). Similar associations were observed after adjustment for Reynolds Risk Score covariables (1.53 [95% CI: 1.20 to 1.95]; p for trend <0.0001); the association remained in separate analyses of CV death (2.66 [95% CI: 1.48 to 4.81]; p for trend <0.0001), myocardial infarction (1.39 [95% CI: 1.02 to 1.88]; p for trend = 0.008), and stroke (1.60 [95% CI: 1.22 to 2.11]; p for trend <0.0001). When added to traditional risk covariables, NT-proBNP improved the c-statistic (0.765 to 0.774; p = 0.0003), categorical net reclassification (0.08; p < 0.0001), and integrated discrimination (0.0105; p < 0.0001). Similar results were observed when NT-proBNP was added to the Reynolds Risk Score. CONCLUSIONS: In this multiethnic cohort of women with numerous CV events, NT-proBNP modestly improved measures of CVD risk prediction.