Faculty Bibliography

OBJECTIVES: This study tested whether myocardial extracellular volume (ECV) is increased in patients with hypertension and atrial fibrillation (AF) undergoing pulmonary vein isolation and whether there is an association between ECV and post-procedural recurrence of AF. BACKGROUND: Hypertension is associated with myocardial fibrosis, an increase in ECV, and AF. Data linking these findings are limited. T1 measurements pre-contrast and post-contrast in a cardiac magnetic resonance (CMR) study provide a method for quantification of ECV. METHODS: Consecutive patients with hypertension and recurrent AF referred for pulmonary vein isolation underwent a contrast CMR study with measurement of ECV and were followed up prospectively for a median of 18 months. The endpoint of interest was late recurrence of AF. RESULTS: Patients had elevated left ventricular (LV) volumes, LV mass, left atrial volumes, and increased ECV (patients with AF, 0.34 +/- 0.03; healthy control patients, 0.29 +/- 0.03; p < 0.001). There were positive associations between ECV and left atrial volume (r = 0.46, p < 0.01) and LV mass and a negative association between ECV and diastolic function (early mitral annular relaxation [E'], r = -0.55, p < 0.001). In the best overall multivariable model, ECV was the strongest predictor of the primary outcome of recurrent AF (hazard ratio: 1.29; 95% confidence interval: 1.15 to 1.44; p < 0.0001) and the secondary composite outcome of recurrent AF, heart failure admission, and death (hazard ratio: 1.35; 95% confidence interval: 1.21 to 1.51; p < 0.0001). Each 10% increase in ECV was associated with a 29% increased risk of recurrent AF. CONCLUSIONS: In patients with AF and hypertension, expansion of ECV is associated with diastolic function and left atrial remodeling and is a strong independent predictor of recurrent AF post-pulmonary vein isolation.

BACKGROUND: Adult height has been hypothesized to be inversely associated with coronary heart disease; however, studies have produced conflicting results. We sought to examine the relationship between adult height and the prevalence of coronary artery calcium (CAC), a direct measure of subclinical atherosclerosis and surrogate marker of coronary heart disease. METHODS AND RESULTS: We evaluated the relationship between adult height and CAC in 2703 participants from the National Heart, Lung, and Blood Institute Family Heart Study who underwent cardiac computed tomography. We used generalized estimating equations to calculate the prevalence odds ratios for the presence of CAC (CAC>0) across sex-specific quartiles of height. The mean age of the sample was 54.8 years, and 60.2% of participants were female. There was an inverse association between adult height and CAC. After adjusting for age, race, field center, waist circumference, smoking, alcohol, physical activity, systolic blood pressure, antihypertensive medications, diabetes mellitus, diabetic medications, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, lipid-lowering medications, and income, individuals in the tallest quartile had 30% lower odds of having prevalent CAC. The odds ratios (95% confidence intervals) for the presence of CAC across consecutive sex-specific quartiles of height were 1.0 (reference), 1.15 (0.86-1.53), 0.95 (0.73-1.22), and 0.70 (0.53-0.93), and P for trend<0.01. There was no evidence of effect modification for the relationship between adult height and CAC by age or socioeconomic status. CONCLUSIONS: The results of our study suggest an inverse, independent association between adult height and CAC.

IMPORTANCE: Randomized trials of anti-hypertensive treatment demonstrating reduced risk of cardiovascular events in older adults included participants with less comorbidity than clinical populations. Whether these results generalize to all older adults, most of whom have multiple chronic conditions, is uncertain. OBJECTIVE: To determine the association between anti-hypertensive medications and CV events and mortality in a nationally representative population of older adults. DESIGN: Competing risk analysis with propensity score adjustment and matching in the Medicare Current Beneficiary Survey cohort over three-year follow-up through 2010. PARTICIPANTS AND SETTING: 4,961 community-living participants with hypertension. EXPOSURE: Anti-hypertensive medication intensity, based on standardized daily dose for each anti-hypertensive medication class participants used. MAIN OUTCOMES AND MEASURES: Cardiovascular events (myocardial infarction, unstable angina, cardiac revascularization, stroke, and hospitalizations for heart failure) and mortality. RESULTS: Of 4,961 participants, 14.1% received no anti-hypertensives; 54.6% received moderate, and 31.3% received high, anti-hypertensive intensity. During follow-up, 1,247 participants (25.1%) experienced cardiovascular events; 837 participants (16.9%) died. Of deaths, 430 (51.4%) occurred in participants who experienced cardiovascular events during follow-up. In the propensity score adjusted cohort, after adjusting for propensity score and other covariates, neither moderate (adjusted hazard ratio, 1.08 [95% CI, 0.89-1.32]) nor high (1.16 [0.94-1.43]) anti-hypertensive intensity was associated with experiencing cardiovascular events. The hazard ratio for death among all participants was 0.79 [0.65-0.97] in the moderate, and 0.72 [0.58-0.91] in the high intensity groups compared with those receiving no anti-hypertensives. Among participants who experienced cardiovascular events, the hazard ratio for death was 0.65 [0.48-0.87] and 0.58 [0.42-0.80] in the moderate and high intensity groups, respectively. Results were similar in the propensity score-matched subcohort. CONCLUSIONS AND RELEVANCE: In this nationally representative cohort of older adults, anti-hypertensive treatment was associated with reduced mortality but not cardiovascular events. Whether RCT results generalize to older adults with multiple chronic conditions remains uncertain.

OBJECTIVE: To characterise the trends in the left ventricular assist device (LVAD) implantation rates and outcomes between 2004 and 2011 in the Medicare population. Since the approval of the HeartMate II in 2008, the use of LVADs has steadily climbed. Given the increase in LVAD use, issues around discharge disposition, post-implant hospitalisations and costs require further understanding. METHODS: We examined LVAD implantation rates and short-term and long-term outcomes among Medicare fee-for-service beneficiaries hospitalised for LVAD implantation. We also conducted analyses among survivors 1-year post-discharge to examine rehospitalisation rates. Lastly, we reported Centers for Medicare & Medicaid Services (CMS) payments for both index hospitalisation and rehospitalisations 1 year post-discharge. RESULTS: A total of 2152 LVAD implantations were performed with numbers increasing from 107 in 2004 to 612 in 2011. The 30-day mortality rate decreased from 52% to 9%, and 1-year mortality rate decreased from 69% to 31%. We observed no change in overall length of stay, but post-procedure length of stay increased. We also found an increase in home discharge dispositions from 26% to 53%. Between 2004 and 2010, the rehospitalisation rate increased and the number of hospital days decreased. The adjusted CMS payment for the index hospitalisation increased from $188 789 to $225 697 over time but decreased for rehospitalisation from $60 647 to $53 630. CONCLUSIONS: LVAD implantations increased over time. We found decreasing 30-day and 1-year mortality rates and increasing home discharge disposition. The proportion of patients rehospitalised among 1-year survivors remained high with increasing index hospitalisation cost, but decreasing post-implantation costs over time.

OBJECTIVES: This study sought to identify the frequency, pattern, and prognostic significance of left ventricular (LV) late gadolinium enhancement (LGE) in patients with atrial fibrillation (AF). BACKGROUND: There are limited data on the presence, pattern, and prognostic significance of LV myocardial fibrosis in patients with AF. LGE during cardiac magnetic resonance imaging is a marker for myocardial fibrosis. METHODS: A group of 664 consecutive patients without known prior myocardial infarction who were referred for radiofrequency ablation of AF were studied. Cardiac magnetic resonance imaging was requested to assess pulmonary venous anatomy. RESULTS: Overall, 73% were men, with a mean age of 56 years and a mean LV ejection fraction of 56 +/- 10%. LV LGE was found in 88 patients (13%). The endpoint was all-cause mortality, and in this cohort, 68 deaths were observed over a median follow-up period of 42 months. On univariate analysis, age (hazard ratio [HR]: 1.05; 95% confidence interval [CI]: 1.03 to 1.08; chi-square likelihood ratio [LRchi(2)]: 15.2; p = 0.0001), diabetes (HR: 2.39; 95% CI: 1.41 to 4.09; LRchi(2): 10.3; p = 0.001), a history of heart failure (HR: 1.78; 95% CI: 1.09 to 2.91; LRchi(2): 5.37; p = 0.02), left atrial dimension (HR: 1.04; 95% CI: 1.01 to 1.08; LRchi(2): 6.47; p = 0.01), presence of LGE (HR: 5.08; 95% CI: 3.08 to 8.36; LRchi(2): 28.8; p < 0.0001), and LGE extent (HR: 1.15; 95% CI: 1.10 to 1.21; LRchi(2): 35.6; p < 0.0001) provided the strongest associations with mortality. The mortality rate was 8.1% per patient-year in patients with LGE compared with 2.3% patients without LGE. In the best overall multivariate model for mortality, age and the extent of LGE were independent predictors of mortality. Indeed, each 1% increase in the extent of LGE was associated with a 15% increased risk for death. CONCLUSIONS: In patients with AF, LV LGE is a frequent finding and is a powerful predictor of mortality.