Rationale, design, and goals of the Advanced Cardiovascular Imaging Consortium (ACIC): A Blue Cross Blue Shield of Michigan collaborative quality improvement project.

BACKGROUND: Coronary computed tomography angiography (CCTA) is an emerging noninvasive anatomical method for evaluation of patients with suspected coronary artery disease (CAD). Multicenter clinical registries are key to efforts to establish the role of CCTA in CAD diagnosis and management. The Advanced Cardiovascular Imaging Consortium (ACIC) is a statewide, multicenter collaborative quality initiative with the intent to establish quality and appropriate use of CCTA in Michigan. METHODS: The ACIC is sponsored by the Blue Cross Blue Shield of Michigan/Blue Care Network, and its 47 sites include imaging centers that offer CCTA and meet established structure and process standards for participation. Patients enrolled include those with suspected ischemia with or without known CAD, and individuals across the entire spectrum of CAD risk. Patient demographics, history, CCTA scan-related data and findings, and 90-day follow-up data are entered prospectively into a centralized database with strict validation tools and processes. Collaborative quality initiatives include radiation dose reduction and appropriate CCTA use by education and feedback to participating sites and referring physicians. CONCLUSIONS: Across a wide range of institutions, the ACIC permits evaluation of "real-world" utilization and effectiveness of CCTA and examines an alternative, nontraditional approach to utilization management wherein physicians and payers collaborate to address the growing problem of cardiac imaging overutilization.

Is it possible to safely administer early a loading dose of clopidogrel before coronary angiography to patients who are candidates for percutaneous coronary intervention?

Current American College of Cardiology/American Heart Association guidelines recommend loading clopidogrel >or=6 hours before percutaneous coronary intervention. Other American College of Cardiology guidelines advise withholding clopidogrel for 5 days before coronary artery bypass grafting (CABG) to avoid excessive bleeding. Previously published rules for predicting early CABG after coronary angiography (CA) were developed in selected patients with non-ST-segment elevation-acute coronary syndrome and not tested in community practice settings. Using logistic regression analysis we sought to develop an accurate decision rule to identify patients at higher risk for early CABG, in unselected community hospital patients undergoing diagnostic CA, who were candidates for percutaneous coronary intervention. The study was conducted at a community hospital in Ann Arbor, Michigan. A total of 986 randomly selected records from 2004 were reviewed. Sixty-two percent were men and mean age was 64 years. Twelve percent underwent CABG within 5 days of CA. Of those with previous CABG, only 2% underwent early CABG. From several potential predictor variables examined, age, male gender, previous CABG, history of typical angina pectoris, previous CA, and hypertension were identified through multivariate logistic regression and incorporated in a simple risk score. Sensitivity and specificity of a risk score >12 were 66% (95% confidence interval 56 to 74) and 66% (95% confidence interval 62 to 69), respectively, with an area under the receiver operating characteristics curve of 0.72. In conclusion, early CABG in those undergoing CA can be predicted with only modest accuracy from preprocedure clinical variables.

Radiation dose from cardiac computed tomography before and after implementation of radiation dose-reduction techniques.

CONTEXT: Cardiac computed tomography angiography (CCTA) can accurately diagnose coronary artery disease, but radiation dose from this procedure is of concern. OBJECTIVES: To determine whether a collaborative radiation dose-reduction program would be associated with reduced radiation dose in patients undergoing CCTA in a statewide registry over a 1-year period and to define its effect on image quality. DESIGN, SETTING, AND PATIENTS: A prospective, controlled, nonrandomized study conducted during a control period (July-August 2007), an intervention period (September 2007-April 2008), and a follow-up period (May-June 2008) at 15 hospital imaging centers participating in the Advanced Cardiovascular Imaging Consortium in Michigan, which included small community hospitals and large academic medical centers. A total of 4995 sequential patients undergoing CCTA for suspected coronary artery disease were enrolled; 4862 patients (97.3%) had complete radiation data for analysis. INTERVENTION: A best-practice CCTA scan model was used, which included minimized scan range, heart rate reduction, electrocardiographic-gated tube current modulation, and reduced tube voltage in suitable patients. MAIN OUTCOME MEASURES: Primary outcomes included dose-length product and effective radiation dose from all phases of the CCTA scan. Secondary outcomes were image quality assessed by a 4-point scale (1 indicated excellent; 2, good; 3, adequate; and 4, nondiagnostic) and frequency of diagnostic-quality scans. RESULTS: Compared with the control period, patients' estimated median radiation dose in the follow-up period was reduced by 53.3% (dose-length product decreased from 1493 mGy x cm [interquartile range {IQR}, 855-1823 mGy x cm] to 697 mGy x cm [IQR, 407-1163 mGy x cm]; P < .001) and effective dose from 21 mSv (IQR, 12-26 mSv) to 10 mSv (IQR, 6-16 mSv) (P < .001). The greatest reduction in dose occurred at low-volume sites. There were no significant changes in median image quality assessment during the control period compared with the follow-up period (median image quality of 2 [images rated as good] vs median image quality of 2; P = .13) or frequency of diagnostic-quality scans (554/620 patients [89%] vs 769/835 patients [92%]; P = .07). CONCLUSION: Consistent application of currently available dose-reduction techniques was associated with a marked reduction in estimated radiation doses in a statewide CCTA registry, without impairment of image quality. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00640068.

Measurement of ejection fraction after myocardial infarction in the population.

OBJECTIVES: To assess the secular trends in left ventricular ejection fraction (LVEF) assessment after myocardial infarction (MI) and to identify the determinants of testing. DESIGN: A population-based MI incidence cohort. METHODS: The use of tests measuring LVEF (echocardiography, radionuclide, and left ventricular [LV] angiography) was examined among all consecutive residents of Olmsted County, MN, hospitalized for a validated incident MI between 1979 and 1998. Baseline characteristics and outcome were ascertained from community medical records. RESULTS: Among 2,317 patients with incident MI, LVEF assessment increased from 1979 to 1986 (22 to 85%; p value for trend = 0.0001) to stabilize thereafter until 1998. During the most recent decade, LVEF was measured during the hospital stay in 81% of the patients. Characteristics associated with lesser use of tests included older age and measurement of ejection fraction within 1 year prior to the index MI. Larger MI size, prolonged hospital stay, and involvement of a cardiologist as a care provider were positively associated with determination of LVEF. CONCLUSIONS: Measurement of LVEF after MI increased in the last 2 decades, but there continues to be a group of patients in whom it is not done. Given the potential benefits of LVEF measurement, including knowledge for risk stratification and therapeutic choices as underscored in recent practice guidelines, there may be additional opportunities for improving outcomes by ensuring its more consistent use. However, as testing for LVEF differs according to patient characteristics, reliance on selected clinically performed LVEF measurements will result in biased estimates of the prevalence of LV dysfunction after MI.

Incidence of heart failure after myocardial infarction: is it changing over time?

Improved survival after myocardial infarction (MI) could result in MI survivors' contributing to the US heart failure epidemic. Conversely, since the severity of MI is declining over time, a decline in post-MI heart failure might also be anticipated. This study tested the hypothesis that the incidence of post-MI heart failure was declining over time in a geographically defined MI incidence cohort. Between 1979 and 1994, 1,537 patients with incident MI and no prior history of heart failure were hospitalized in Olmsted County, Minnesota. Framingham Heart Study criteria were used to ascertain the incidence of inpatient and outpatient heart failure over a mean follow-up period of 7.6 years (standard deviation 5.5). Overall, 36% of patients experienced heart failure. After adjustment for factors related to post-MI heart failure (age, hypertension, smoking, and biomarkers), the incidence of heart failure declined by 2% per year (relative risk = 0.98, 95% confidence interval: 0.96, 0.99; p = 0.01). The relative risk of developing heart failure among persons with MIs occurring in 1994 versus 1979 was 0.72 (95% confidence interval: 0.55, 0.93), indicating a 28% reduction in the incidence of heart failure. Administration of reperfusion therapy within 24 hours after MI was associated with lower risk of post-MI heart failure and accounted for most of the temporal decline in heart failure. This suggests that improved survival after MI is unlikely to be a major contributor to the heart failure epidemic.

Coronary heart disease death and sudden cardiac death: a 20-year population-based study.

Trends in out-of-hospital coronary heart disease (CHD) death, a surrogate for sudden cardiac death (SCD), are important for understanding the decline in CHD mortality. Little is known about out-of-hospital CHD death without prior CHD diagnosis, the definition of unexpected SCD. The authors analyzed secular trends in CHD death and unexpected SCD over a 20-year period (1979-1998) to examine the association between prior CHD and SCD and to test the hypothesis that in-hospital deaths declined more than SCDs. The yearly decline in CHD mortality rates was 5.3% for in-hospital deaths and 1.8% for out-of-hospital deaths (p = 0.001). Among all SCDs, the proportion of unexpected SCD was 49%. Mortality rates for both unexpected SCD and SCD with prior CHD declined over time, but unexpected SCD declined at a slower rate than SCD with prior CHD (p = 0.001). The relative odds of prior CHD were higher among persons with SCD than among controls, but there was a modest decline in the magnitude of the association. Thus, during the past 20 years, the decline was greater for in-hospital CHD deaths than for SCDs. Since approximately half of the SCDs were unexpected and rates of these deaths declined less over time than rates of SCD with prior CHD, primary prevention is becoming increasingly more important in sustaining the decline in CHD mortality.

Opportunities to prevent sudden out-of-hospital death due to coronary heart disease in a community.

BACKGROUND: Intervening successfully to reduce the burden of sudden out-of-hospital death due to coronary heart disease (OHCD) requires knowledge of where these deaths occur and whether they are observed by bystanders. METHODS: To establish the proportion of OHCDs that were witnessed and where they occurred, we reviewed the coroner's notes and medical records of a previously-described sample of OHCD cases among residents of Olmsted County, Minnesota. This cohort (n=113) consisted of a 10% random sample of all Olmsted County residents who died out-of-hospital between 1981 and 1994 and whose deaths were attributed to coronary heart disease. RESULTS: Excluding deaths in nursing homes (n=27), 71 (83%) of the deaths occurred in private homes and 15 (17%) occurred in public places. The event was not witnessed in 59% of deaths occurring in private homes and in 20% of deaths occurring in public places. The presence or absence of a bystander could not be established for 10% of deaths in private homes and 7% of deaths in public areas. CONCLUSIONS: A significant proportion of OHCDs occur in private homes and are not witnessed. Prevention of unwitnessed deaths will require programs that result in primary prevention and/or calls to first responders at the time of impending cardiac arrest.

Coronary atherosclerosis in diabetes mellitus: a population-based autopsy study.

OBJECTIVES: The study was conducted to test the hypothesis that the prevalence of coronary atherosclerosis is greater among diabetic than among nondiabetic individuals and is similar for diabetic individuals without clinical coronary artery disease (CAD) and nondiabetics with clinical CAD. BACKGROUND: Persons with diabetes but without clinical CAD encounter cardiovascular mortality similar to nondiabetic individuals with clinical CAD. This excess mortality is not fully explained. We examined the association between diabetes and coronary atherosclerosis in a geographically defined autopsied population, while capitalizing on the autopsy rate and medical record linkage system available via the Rochester Epidemiology Project, which allows rigorous ascertainment of coronary atherosclerosis, clinical CAD, and diabetes. METHODS: Using two measures, namely a global coronary score and high-grade stenoses, the prevalence of atherosclerosis was analyzed in a cohort of autopsied residents of Rochester, Minnesota, age 30 years or older at death, while stratifying on diabetes, clinical CAD diagnosis, age, and gender. RESULTS: In this cohort, diabetes was associated with a higher prevalence of atherosclerosis. Among diabetic decedents without clinical CAD, almost three-fourths had high-grade coronary atherosclerosis and more than half had multivessel disease. Without diabetes, women had less atherosclerosis than men, but this female advantage was lost with diabetes. Among those without clinical CAD, diabetes was associated with a global coronary disease burden and a prevalence of high-grade atherosclerosis similar to that observed among nondiabetic subjects with clinical CAD. CONCLUSIONS: These findings provide mechanistic insights into the excess risk of clinical CAD among diabetic individuals, thereby supporting the need for aggressive prevention of atherosclerosis in all diabetic individuals, irrespective of clinical CAD symptoms.

Coronary disease surveillance in Olmsted County objectives and methodology.

The community surveillance study of coronary heart disease (CHD) in Olmsted County, MN, is designed to estimate trends in myocardial infarction (MI) incidence, case fatality rate, and CHD mortality, while including all ages. A distinctive feature of this study is its ability to capture longitudinal data before and after index events via the medical record linkage system of the Rochester Epidemiology Project. The goal of this report is to describe the methods implemented to measure CHD trends, the implications of including elderly individuals on MI ascertainment and trends in prior CHD among persons with incident MI. The methods are based on standardized criteria involving the review of death certificate information and hospital records to identify CHD deaths, and incident MIs in Olmsted County. The medical record linkage system in place under the auspices of the Rochester Epidemiology Project was used to ascertain antecedent CHD and outcomes. Hospitalized MIs were screened from sampled events coded ICD9 codes 410-414 and classified using enzyme values, cardiac pain, and ECG coding. After screening 5,042 records, a cohort of 1,658 validated incident MIs was assembled 35% (575) among persons aged 75 years or greater. The proportion of MIs validated with cardiac pain and enzymes without Minnesota ECG coding was lower among the elderly than among persons less than 75 years of age (35 vs. 29%, respectively; P <.001). The proportion of events validated without requiring ECG coding decreased over time in both age strata (P for trend.001). Reliability analyses indicated excellent agreement in event classification. More than half of the incident MIs did not have antecedent CHD, and this proportion increased overtime. These data indicate that the elderly contribute approximately one-third of the cases of incident MI, underscoring the importance of including all ages to fully characterize the burden of CHD. Cases among elderly persons more frequently require ECG coding for validation, but standardized ascertainment procedures are feasible and reliable in all age groups. More than half of the incident MIs occurred among persons with no prior CHD, and this proportion increased over time. The combination of standardized methodology and of the longitudinal data via the record linkage system of the Rochester Epidemiology Project will allow reliable measures of CHD trends and help define preventive strategies.

Trends in the incidence and survival of patients with hospitalized myocardial infarction, Olmsted County, Minnesota, 1979 to 1994.

BACKGROUND: Evidence indicates that deaths from coronary disease are decreasing less in elderly persons and women. Understanding the determinants of these trends is important for prevention. OBJECTIVE: To test the hypothesis that trends in incidence and survival of hospitalized myocardial infarction differ according to sex and age. DESIGN: Longitudinal observational study. SETTING: Community-dwelling persons in Olmsted County, Minnesota. PATIENTS: 5117 patients who had an estimated 1820 incident myocardial infarctions from 1979 to 1994. MEASUREMENTS: Myocardial infarctions were validated by using epidemiologic criteria. Rates were directly adjusted to the age distribution of the 2000 U.S. population. RESULTS: Of the 1820 incident infarctions, 44% occurred in women and 36% in persons 75 years of age or older. In 1979, the age-adjusted incidence of myocardial infarction was 205 per 100 000 persons (95% CI, 162 to 247 per 100 000 persons). Between 1979 and 1994, the age-adjusted incidence of myocardial infarction decreased by 8% (CI, -23% to 10%) in men but increased by 36% (CI, 9% to 70%) in women. A 31% decrease in the incidence of infarction over time was observed in men 40 years of age compared with a 49% increase in women 80 years of age. Survival improved predominantly in younger persons. CONCLUSIONS: Over time, the incidence of hospitalized infarction decreased in men but increased in women and elderly persons. Survival benefits were clustered among younger persons. These results suggest that both incidence and survival contribute to the contrasting mortality trends by age and sex and that the burden of coronary disease has shifted toward elderly persons, a finding that has public health implications in an aging population.