Faculty Bibliography

BACKGROUND: Outdoor fine particulate matter (PM2.5) has been identified as a global health threat, but the number of large U.S. prospective cohort studies with individual participant data remains limited, especially at lower recent exposures. OBJECTIVES: To test the relationship between long-term exposure PM2.5 and death risk from all non-accidental causes, cardiovascular (CVD), and respiratory diseases in 517,041 men and women enrolled in the National Institutes of Health-AARP cohort. METHODS: Individual participant data were linked with residence PM2.5 exposure estimates across the continental U.S for a 2000-2009 follow up period when matching census-tract level PM2.5 exposure data were available. Participants enrolled ranged from 50-71 yrs. of age, residing in 6 U.S. States and 2 cities. Cox Proportional Hazard models yielded Hazard Ratio (HR) estimates per 10 microg/m3 of PM2.5 exposure. RESULTS: PM2.5 exposure was significantly associated with total mortality (HR= 1.03, 95% CI =1.00, 1.05) and CVD mortality (HR=1.10, 95% CI=1.05, 1.15), but the association with respiratory mortality was not statistically significant (HR=1.05, 95% CI=0.98,1.13). A significant association was found with respiratory mortality only among never smokers (HR=1.27; 95% CI: 1.03, 1.56). Associations with 10 microg/m3 PM2.5 exposures in yearly participant residential annual mean, or in metropolitan area-wide mean, were consistent with baseline exposure model results. Associations with PM2.5 were similar when adjusted for ozone exposures. Analyses of California residents alone also yielded statistically significant PM2.5 mortality HR's for total and CVD mortality. CONCLUSIONS: Long-term exposure to PM2.5 air pollution was associated with an increased risk of total and CVD mortality, providing an independent test of the PM2.5 - mortality relationship in a new large U.S. prospective cohort experiencing lower post-2000 PM2.5 exposure levels.

Takotsubo cardiomyopathy (TC) often occurs after emotional or physical stress. Norepinephrine levels are unusually high in the acute phase, suggesting a hyperadrenergic mechanism. Comparatively little is known about parasympathetic function in patients with TC. We sought to characterize autonomic function at rest and in response to physical and emotional stimuli in 10 women with a confirmed history of TC and 10 age-matched healthy women. Sympathetic and parasympathetic activity was assessed at rest and during baroreflex stimulation (Valsalva maneuver and tilt testing), cognitive stimulation (Stroop test), and emotional stimulation (event recall, patients). Ambulatory blood pressure monitoring and measurement of brachial artery flow-mediated vasodilation were also performed. TC women (tested an average of 37 months after the event) had excessive pressor responses to cognitive stress (Stroop test: p <0.001 vs baseline and p = 0.03 vs controls) and emotional arousal (recall of TC event: p = 0.03 vs baseline). Pressor responses to hemodynamic stimuli were also amplified (Valsalva overshoot: p <0.05) and prolonged (duration: p <0.01) in the TC women compared with controls. Plasma catecholamine levels did not differ between TC women and controls. Indexes of parasympathetic (vagal) modulation of heart rate induced by respiration and cardiovagal baroreflex gain were significantly decreased in the TC women versus controls. In conclusion, even long after the initial episode, women with previous episode of TC have excessive sympathetic responsiveness and reduced parasympathetic modulation of heart rate. Impaired baroreflex control may therefore play a role in TC.

BACKGROUND: Individuals referred for stress testing to identify coronary artery disease may have nonobstructive atherosclerosis, which is not detected by stress tests. Identification of increased risk despite a negative stress test could inform prevention efforts. Abnormal ankle-brachial index (ABI) is associated with increased cardiovascular risk. HYPOTHESIS: Routine ABI testing in the stress laboratory will identify unrecognized peripheral arterial disease in some patients. METHODS: Participants referred for stress testing without known history of atherosclerotic disease underwent ABI testing (n = 451). Ankle-brachial index was assessed via simultaneous arm and leg pressure using standard measurement, automated blood-pressure cuffs at rest. Ankle-brachial index was measured after exercise in 296 patients and 30 healthy controls. Abnormal postexercise ABI was defined as a >20% drop in ABI or fall in ankle pressure by >30 mm Hg. RESULTS: Overall, 2.0% of participants had resting ABI /=1.40, and 5.5% had borderline ABI. No patient with abnormal or borderline ABI had an abnormal stress test. Participants who met peripheral arterial disease screening criteria (age >/=65 or 50-64 with diabetes or smoking) tended toward greater frequency of low ABI (2.9% vs 1.0%; P = 0.06) and were more likely to have borderline ABI (0.91 to 0.99; 7.8% vs 2.9%; P = 0.006). Postexercise ABI was abnormal in 29.4% of patients and 30.0% of controls (P not significant). CONCLUSIONS: Ankle-brachial index screening at rest just before stress testing detected low ABI in 2.0% of participants, all of whom had negative stress tests.

BACKGROUND: Ischemic heart disease (IHD) mortality has been on the decline in the United States for decades. However, declines in IHD mortality have been slower in certain groups, including young women and black individuals. HYPOTHESIS: Trends in IHD vary by age, sex, and race in New York City (NYC). Young female minorities are a vulnerable group that may warrant renewed efforts to reduce IHD. METHODS: IHD mortality trends were assessed in NYC 1980-2008. NYC Vital Statistics data were obtained for analysis. Age-specific IHD mortality rates and confidence bounds were estimated. Trends in IHD mortality were compared by age and race/ethnicity using linear regression of log-transformed mortality rates. Rates and trends in IHD mortality rates were compared between subgroups defined by age, sex and race/ethnicity. RESULTS: The decline in IHD mortality rates slowed in 1999 among individuals aged 35-54 years but not >/=55. IHD mortality rates were higher among young men than women age 35-54, but annual declines in IHD mortality were slower for women. Black women age 35-54 had higher IHD mortality rates and slower declines in IHD mortality than women of other race/ethnicity groups. IHD mortality trends were similar in black and white men age 35-54. CONCLUSIONS: The decline in IHD mortality rates has slowed in recent years among younger, but not older, individuals in NYC. There was an association between sex and race/ethnicity on IHD mortality rates and trends. Young black women may benefit from targeted medical and public health interventions to reduce IHD mortality.

The exercise ECG is an integral part within the evaluation algorithm for diagnosis and risk stratification of patients with stable ischaemic heart disease (SIHD). There is evidence, both older and new, that the exercise ECG can be an effective and cost-efficient option for patients capable of performing at maximal levels of exercise with suitable resting ECG findings. In this review, we will highlight the major dilemmas in interpreting suspected coronary artery disease symptoms in women and identify optimal strategies for employing exercise ECG as a first-line diagnostic test in the SIHD evaluation algorithm. We will highlight current evidence as well as recent guideline statements on this subject. TRIAL REGISTRATION NUMBER: NCT01471522; Pre-results.

BACKGROUND: Stress echocardiography (SE) is dependent on subjective interpretations. As a prelude to the International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) Trial, potential sites were required to submit two SE, one with moderate or severe left ventricular (LV) myocardial ischemia and one with mild ischemia. We evaluated the concordance of site and core lab interpretations. METHODS: Eighty-one SE were submitted from 41 international sites. Ischemia was classified by the number of new or worsening segmental LV wall motion abnormalities (WMA): none, mild (1 or 2) or moderate or severe (3 or more) by the sites and the core lab. RESULTS: Core lab classified 6 SE as no ischemia, 35 mild and 40 moderate or greater. There was agreement between the site and core in 66 of 81 total cases (81 %, weighted kappa coefficient [K] =0.635). Agreement was similar for SE type - 24 of 30 exercise (80 %, K = 0.571) vs. 41 of 49 pharmacologic (84 %, K = 0.685). The agreement between poor or fair image quality (27 of 36 cases, 75 %, K = 0.492) was not as good as for the good or excellent image quality cases (39 of 45 cases, 87 %, K = 0.755). Differences in concordance were noted for degree of ischemia with the majority of discordant interpretations (87 %) occurring in patients with no or mild LV myocardial ischemia. CONCLUSIONS: While site SE interpretations are largely concordant with core lab interpretations, this appears dependent on image quality and the extent of WMA. Thus core lab interpretations remain important in clinical trials where consistency of interpretation across a range of cases is critical. TRIAL REGISTRATION: ClinicalTrials.gov NCT01471522.

BACKGROUND: Over the past decade, ischemic heart disease (IHD) mortality trends have been less favorable among adults age 25-54 than age >/=55 years. HYPOTHESIS: Disorders associated with IHD such as diabetes, chronic inflammatory and infectious diseases, and cocaine use are important contributors to premature IHD mortality. METHODS: Multiple-cause-of-death analysis was performed using the New York City (NYC) Vital Statistics database. Frequencies of selected contributing causes on death records with IHD as the underlying cause for decedents age >/=25 were assessed (n = 418,151; 1990-2008). Concurrent Telephone risk-factor surveys (NYC Community Health Survey, Centers for Disease Control Behavioral Risk Factor Survey in New York State) were analyzed. RESULTS: In sum, a prespecified contributing cause was identified on 13.6% of death certificates for IHD decedents age 25-54. Diabetes was reported more frequently for younger IHD decedents (15% of females and 10% of males age 25-54 vs 6% of both sexes age >/= 55). In contrast, concurrent diabetes prevalence in New York State was 3.4% for those age 25-54 and 13.6% for those age >55 (P < 0.0001). Systemic lupus erythematosus, human immunodeficiency virus, and cocaine were also more likely to contribute to IHD death among younger than older people. CONCLUSIONS: Diabetes may be a potent risk factor for IHD death in young people, particularly young women, in whom it was reported on IHD death records at a rate 5x higher than local prevalence. The high frequency of reporting of studied contributing causes in younger IHD decedents may provide a focus for further IHD mortality-reduction efforts in younger adults.