Faculty Bibliography

BACKGROUND: Mortality rates after aortic valve replacement have declined, but little is known about the risk of hospitalization among survivors and how that has changed with time. METHODS: Among Medicare patients who underwent aortic valve replacement from 1999 to 2010 and survived to 1 year, we assessed trends in 1-year hospitalization rates, mean cumulative length of stay (average number of hospitalization days per patient in the entire year), and adjusted annual Medicare payments per patient toward hospitalizations. We characterized hospitalizations by principal diagnosis and mean length of stay. RESULTS: Among 1-year survivors of aortic valve replacement, 43% of patients were hospitalized within that year, of whom 44.5% were hospitalized within 30 days (19.2% for overall cohort). Hospitalization rates were higher for older (50.3% for >85 years), female (45.1%), and black (48.9%) patients. One-year hospitalization rate decreased from 44.2% (95% confidence interval, 43.5 to 44.8) in 1999 to 40.9% (95% confidence interval, 40.3 to 41.4) in 2010. Mean cumulative length of stay decreased from 4.8 days to 4.0 days (p < 0.05 for trend); annual Medicare payments per patient were unchanged ($5,709 to $5,737; p = 0.32 for trend). The three most common principal diagnoses in hospitalizations were heart failure (12.7%), arrhythmia (7.9%), and postoperative complications (4.4%). Mean length of stay declined from 6.0 days to 5.3 days (p < 0.05 for trend). CONCLUSIONS: Among Medicare beneficiaries who survived 1 year after aortic valve replacement, 3 in 5 remained free of hospitalization; however, certain subgroups had higher rates of hospitalization. After the 30-day period, the hospitalization rate was similar to that of the general Medicare population. Hospitalization rates and cumulative days spent in hospital decreased with time.

BACKGROUND: Stroke is a common and important adverse event after acute myocardial infarction (AMI) in the elderly. It is unclear whether the risk of stroke after AMI has changed with improvements in treatments and outcomes for AMI in the last decade. METHODS: To assess trends in risk of stroke after AMI, we used a national sample of Medicare data to identify Fee-for-Service patients (n = 2,305,441) aged >/=65 years who were discharged alive after hospitalization for AMI from 1999 to 2010. RESULTS: We identified 57,848 subsequent hospitalizations for ischemic stroke and 4,412 hospitalizations for hemorrhagic stroke within 1 year after AMI. The 1-year rate of ischemic stroke decreased from 3.4% (95% CI 3.3%-3.4%) to 2.6% (2.5%-2.7%; P < .001). The risk-adjusted annual decline was 3% (hazard ratio, 0.97; [0.97-0.98]) and was similar across all age and sex-race groups. The rate of hemorrhagic stroke remained stable at 0.2% and did not differ by subgroups. The 30-day mortality for patients admitted with ischemic stroke after AMI decreased from 19.9% (18.8%-20.9%) to 18.3% (17.1%-19.6%) and from 48.3% (43.0%-53.6%) to 45.7% (40.3%-51.2%) for those admitted with hemorrhagic stroke. We observed a decrease in 1-year mortality from 37.8% (36.5%-39.1%) to 35.3% (33.8%-36.8%) for ischemic stroke and from 66.6% (61.4%-71.5%) to 60.6% (55.1%-65.9%) for hemorrhagic stroke. CONCLUSIONS: From 1999 to 2010, the 1-year risk for ischemic stroke after AMI declined, whereas the risk of hemorrhagic stroke remained unchanged. However, 30-day and 1-year mortality continued to be high.

BACKGROUND: Older patients who undergo mitral valve surgery (MVS) have high 1-year survival rates, but little is known about the experience of survivors. Our objective was to determine trends in 1-year hospital readmission rates and length of stay (LOS) in these individuals. METHODS: We included 100% of Medicare Fee-for-Service patients >/=65 years of age who underwent MVS between 1999-2010 and survived to 1 year (N = 146,877). We used proportional hazards regression to analyze the post-MVS 1-year readmission rate in each year, mean hospital LOS (after index admission), and readmission rates by subgroups (age, sex, race). RESULTS: The 1-year survival rate among patients undergoing MVS was 81.3%. Among survivors, 49.1% experienced a hospital readmission within 1 year. The post-MVS 1-year readmission rate declined from 1999-2010 (49.5% to 46.9%, P<0.01), and mean hospital LOS decreased from 6.2 to 5.3 (P<0.01). Readmission rates were highest in oldest patients, but declined in all age subgroups (65-74: 47.4% to 44.4%; 75-84: 51.4% to 49.2%, >/=85: 56.4% to 50.0%, all P<0.01). There were declines in women and men (women: 51.7% to 50.8%, P<0.01; men: 46.9% to 43.0%, P<0.01), and in whites and patients of other race, but not in blacks (whites: 49.0% to 46.2%, P<0.01; other: 55.0% to 48.9%, P<0.01; blacks: 58.1% to 59.0%, P = 0.18). CONCLUSIONS: Among older adults surviving MVS to 1 year, slightly fewer than half experience a hospital readmission. There has been a modest decline in both the readmission rate and LOS over time, with worse outcomes in women and blacks.

Introduction: Clinicians are hesitant to prescribe oral anticoagulants to older adults with atrial fibrillation (AF) due to concerns over bleeding risk. Hypothesis: As many data on bleeding events are from trials of rigorously selected patients, we hypothesized that major bleeding events (requiring hospitalization) would be more common than previously reported. Methods: We created a retrospective cohort of 31,951 Veterans with AF aged >75 years who were new referrals to VA anticoagulation clinics (warfarin) from 1/1/02 - 12/31/12. Patients with comorbid conditions requiring warfarin (e.g. pulmonary embolus) were excluded. Data were extracted from the VA electronic medical record and linked with Medicare claims data for subsequent hospitalizations. The primary outcome was any hospitalization for bleeding. We identified bleeding subtypes by source, and compared characteristics of patients with and without bleeding hospitalizations. Results: Mean population age was 81.1 years, 98.1% were male, and 8.4% were nonwhite. Over a median follow-up period of 2.62 years, 7288 patients (22.8%) were hospitalized for bleeding. There were 12,004 total bleeding events; overall, 980 (13.4%) patients experienced multiple events. The most common bleeding sources (first event) were gastrointestinal (50.8%), genitourinary (21.6%), and intracranial (9.4%) (Figure). The median time to first bleeding event was 1.59 years. Patients hospitalized for bleeding were more likely to have coronary disease (48.4% vs. 40.9%, P<0.01); COPD (28.4% vs. 24.7%, P<0.01); chronic kidney disease (17.8% vs. 16.0%, P<0.01); CHF (34.7% vs. 29.5%, P<0.01), and labile INR (63.3% vs. 53.7%, P<0.01). The rate of hospitalization for stroke over the same time period was 5.0%. Conclusions: After initiating warfarin, over one in five older Veterans are hospitalized for bleeding, most commonly from a gastrointestinal source. Comorbidity burden and labile INR place these patients at increased risk

BackgroundWhile older adults (age 75 and over) represent a large and growing proportion of patients with acute myocardial infarction (AMI), they have traditionally been under-represented in cardiovascular studies. Although chronological age confers an increased risk for adverse outcomes, our current understanding of the heterogeneity of this risk is limited. The Comprehensive Evaluation of Risk Factors in Older Patients with AMI (SILVER-AMI) study was designed to address this gap in knowledge by evaluating risk factors (including geriatric impairments, such as muscle weakness and cognitive impairments) for hospital readmission, mortality, and health status decline among older adults hospitalized for AMI.Methods/DesignSILVER-AMI is a prospective cohort study that is enrolling 3000 older adults hospitalized for AMI from a recruitment network of approximately 70 community and academic hospitals across the United States. Participants undergo a comprehensive in-hospital assessment that includes clinical characteristics, geriatric impairments, and health status measures. Detailed medical record abstraction complements the assessment with diagnostic study results, in-hospital procedures, and medications. Participants are subsequently followed for six months to determine hospital readmission, mortality, and health status decline. Multivariable regression will be used to develop risk models for these three outcomes.DiscussionSILVER-AMI will fill critical gaps in our understanding of AMI in older patients. By incorporating geriatric impairments into our understanding of post-AMI outcomes, we aim to create a more personalized assessment of risk and identify potential targets for interventions.Trial registrationTrial registration number: NCT01755052.

BACKGROUND: The epidemiology of aortic dissection (AD) has not been well described among older persons in the United States. It is not known whether advancements in AD care over the last decade have been accompanied by changes in outcomes. METHODS AND RESULTS: The Inpatient Medicare data from 2000 to 2011 were used to determine trends in hospitalization rates for AD. Mortality rates were ascertained through corresponding vital status files. A total of 32 057 initial AD hospitalizations were identified. The overall hospitalization rate for AD remained unchanged at 10 per 100 000 person-years. For 30-day and 1-year mortality associated with AD, the observed rate decreased from 31.8% to 25.4% (difference, 6.4%; 95% confidence interval [CI], 6.2-6.5; adjusted, 6.4%; 95% CI, 5.7-6.9) and from 42.6% to 37.4% (difference, 5.2%; 95% CI, 5.1-5.2; adjusted, 6.2%; 95% CI, 5.3-6.7), respectively. For patients undergoing surgical repair for type A dissections, the observed 30-day mortality decreased from 30.7% to 21.4% (difference, 9.3%; 95% CI, 8.3-10.2; adjusted, 7.3%; 95% CI, 5.8-7.8) and the observed 1-year mortality decreased from 39.9% to 31.6% (difference, 8.3%; 95% CI, 7.5-9.1%; adjusted, 8.2%; 95% CI, 6.7-9.1). The 30-day mortality decreased from 24.9% to 21% (difference, 3.9%; 95% CI, 3.5-4.2; adjusted, 2.9%; 95% CI, 0.7-4.4) and 1-year decreased from 36.4% to 32.5% (difference, 3.9%; 95% CI, 3.3-4.3; adjusted, 3.9%; 95% CI, 2.5-6.3) for surgical repair of type B dissection. CONCLUSIONS: Although AD hospitalization rates remained stable, improvement in mortality was noted, particularly in patients undergoing surgical repair.

BACKGROUND: Elevated resting pulse rate (RPR) is a well-recognized risk factor for adverse outcomes. Epidemiological evidence supports the beneficial effects of regular exercise for lowering RPR, but studies are mainly confined to persons younger than 65 years. We set out to evaluate the utility of a physical activity (PA) intervention for slowing RPR among older adults. METHODS: A total of 424 seniors (ages 70-89 years) were randomized to a moderate intensity PA intervention or an education-based "successful aging" health program. Resting pulse rate was assessed at baseline, 6 months, and 12 months. Longitudinal differences in RPR were evaluated between treatment groups using generalized estimating equation models, reporting unstandardized beta coefficients with robust SEs. RESULTS: Increased frequency and duration of aerobic training were observed for the PA group at 6 and 12 months as compared with the successful aging group (P < .001). In both groups, RPR remained unchanged over the course of the 12-month study period (P = .67). No significant improvement was observed (beta [SE] = 0.58 [0.88]; P = .51) for RPR when treatment groups were compared using the generalized estimating equation method. Comparable results were found after omitting participants with a pacemaker, cardiac arrhythmia, or who were receiving beta-blockers. CONCLUSIONS: Twelve months of moderate intensity aerobic training did not improve RPR among older adults. Additional studies are needed to determine whether PA of longer duration and/or greater intensity can slow RPR in older persons.

BACKGROUND: There are few data characterizing temporal changes in hospitalization for recurrent acute myocardial infarction (AMI) after AMI. METHODS AND RESULTS: Using a national sample of 2 305 441 Medicare beneficiaries hospitalized for AMI from 1999 to 2010, we evaluated changes in the incidence of 1-year recurrent AMI hospitalization and mortality using Cox proportional hazards models. The observed recurrent AMI hospitalization rate declined from 12.1% (95% CI 11.9 to 12.2) in 1999 to 8.9% (95% CI 8.8 to 9.1) in 2010, a relative decline of 26.4%. The observed recurrent AMI hospitalization rate declined by a relative 27.7% in whites, from 11.9% (95% CI 11.8 to 12.1) to 8.6% (95% CI 8.5 to 8.8) versus a relative decline in blacks of 13.6% from 13.2% (95% CI 12.6 to 13.8) to 11.4% (95% CI 10.9 to 12.0). The risk-adjusted rate of annual decline in recurrent AMI hospitalizations was 4.1% (HR 0.959; 95% CI 0.958 to 0.961), and whites experienced a higher rate of decline (HR 0.957, 95% CI 0.956 to 0.959) than blacks (HR 0.974, 95% CI 0.970 to 0.979).The overall, observed 1-year mortality rate after hospitalization for recurrent AMI declined from 32.4% in 1999 to 29.7% in 2010, a relative decline of 8.3% (P<0.05). In adjusted analyses, 1-year mortality after recurrent AMI hospitalization declined 1.8% per year (HR, 0.982; 95% CI 0.980 to 0.985). CONCLUSIONS: In a national sample of Medicare beneficiaries hospitalized for AMI from 1999 to 2010, hospitalization for recurrent AMI decreased, as did subsequent mortality, albeit to a lesser extent. The risk of recurrent AMI hospitalization declined less in black patients than in whites, increasing observed racial disparities by the end of the study period.

BACKGROUND: Although pulmonary vein isolation has become a mainstream therapy for selected patients with atrial fibrillation (AF), late recurrent AF is common and its risk factors remain poorly defined. The purpose of our study was to test the hypothesis that reduced left atrial passive emptying function (LAPEF) as determined by cardiac magnetic resonance has a strong association with late recurrent AF after pulmonary vein isolation. METHODS AND RESULTS: Three hundred forty-six patients with AF referred for cardiac magnetic resonance pulmonary vein mapping before pulmonary vein isolation were included. Maximum LA volumes (VOLmax) and volumes before atrial contraction (VOLbac) were measured; LAPEF was calculated as (VOLmax-VOLbac)/VOLmaxx100. Kaplan-Meier curves were constructed to determine late recurrent AF stratified by LAPEF quintile. Cox proportional hazards regression was used to adjust for known markers of recurrence. During a median follow-up of 27 months, 124 patients (35.8%) experienced late recurrent AF. Patients with recurrence were more likely to have nonparoxysmal AF (75.8% versus 51.4%; P<0.01), higher mean VOLmax (60.2 versus 52.8 mL/m(2); P<0.01), and lower mean LAPEF (19.1% versus 26.0%; P<0.01). Patients in the lowest LAPEF quintile were at highest risk of developing recurrent AF (2-year recurrence for lowest versus highest: 60.5% versus 17.3%; P<0.01). After adjusting for known predictors of recurrence, patients with low LAPEF remained significantly more likely to recur (hazard ratio for lowest versus highest quintile, 3.92; 95% confidence interval, 2.01-7.65). CONCLUSIONS: We found a strong association between LAPEF and recurrent AF after pulmonary vein isolation that persisted after multivariable adjustment.