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1.  Comparison of Clinical Interpretation with Visual Assessment and Quantitative Coronary Angiography in Patients Undergoing Percutaneous Coronary Intervention in Contemporary Practice: The Assessing Angiography (A2) Project 
Circulation  2013;127(17):1793-1800.
Studies conducted decades ago described substantial disagreement and errors in physicians’ angiographic interpretation of coronary stenosis severity. Despite the potential implications of such findings, no large-scale efforts to measure or improve clinical interpretation were subsequently made.
Methods & Results
We compared clinical interpretation of stenosis severity in coronary lesions with an independent assessment using quantitative coronary angiography (QCA) in 175 randomly selected patients undergoing elective percutaneous coronary intervention (PCI) at 7 U.S. hospitals in 2011. To assess agreement, we calculated mean difference in percent diameter stenosis between clinical interpretation and QCA and a Cohen’s weighted kappa statistic. Of 216 treated lesions, median percent diameter stenosis was 80.0% (Q1 and Q3, 80.0 and 90.0%) with 213 (98.6%) assessed as ≥70%. Mean difference in percent diameter stenosis between clinical interpretation and QCA was +8.2 ± 8.4%, reflecting an average higher percent diameter stenosis by clinical interpretation (P<0.001). A weighted kappa of 0.27 (95% CI, 0.18 to 0.36) was found between the 2 measurements. Of 213 lesions considered ≥70% by clinical interpretation, 56 (26.3%) were <70% by QCA though none was <50%. Differences between the 2 measurements were largest for intermediate lesions by QCA (50 to <70%) with variation existing across sites.
Physicians tended to assess coronary lesions treated with PCI as more severe than measurements by QCA. Almost all treated lesions were ≥70% by clinical interpretation, while approximately a quarter were <70% by QCA. These findings suggest opportunities to improve clinical interpretation of coronary angiography.
PMCID: PMC3908681  PMID: 23470859
Health policy and outcomes research; Quality improvement; Coronary angiography; Percutaneous coronary intervention; Quantitative coronary angiography
2.  What Is the Experience of National Quality Campaigns? Views from the Field 
Health Services Research  2010;45(6 Pt 1):1651-1669.
To identify key characteristics of a national quality campaign that participants viewed as effective, to understand mechanisms by which the campaign influenced hospital practices, and to elucidate contextual factors that modified the perceived influence of the campaign on hospital improvements.
Data Sources
In-depth interviews, hospital surveys, and Health Quality Alliance data.
Study Design
We conducted a qualitative study using in-depth interviews with clinical and administrative staff (N=99) at hospitals reporting strong influence (n=6) as well as hospitals reporting limited influence (n=6) of the Door-to-Balloon (D2B) Alliance, a national quality campaign to improve heart attack care. We analyzed these qualitative data as well as changes in hospital use of recommended strategies reported through a hospital survey and changes in treatment times using Health Quality Alliance data.
Data Collection Methods
In-depth, open-ended interviews; hospital survey.
Principal Findings
Key characteristics of the national quality campaign viewed as enhancing its effectiveness were as follows: credibility of the recommendations, perceived simplicity of the recommendations, alignment with hospitals' strategic goals, practical implementation tools, and breadth of the network of peer hospitals in the D2B Alliance. Perceived mechanisms of the campaign's influence included raising awareness and influencing goals, fostering strategy adoption, and influencing aspects of organizational culture. Modifying contextual factors included perceptions about current performance and internal championship for the recommended changes.
The impact of national quality campaigns may depend on both campaign design features and on the internal environment of participating hospitals.
PMCID: PMC3026952  PMID: 20698898
Quality improvement; campaigns; hospitals; acute myocardial infarction
3.  Operator Experience and Outcomes with Carotid Stenting in Medicare Beneficiaries 
Although the efficacy of carotid stenting has been established in clinical trials, operator experience and outcomes with the procedure in routine clinical practice are less certain.
To correlate outcomes with 2 measures of operator experience: (1) annual volume; and (2) experience at the time of the procedure among new operators who first performed carotid stenting after a national coverage decision by the Centers for Medicare & Medicaid Services (CMS).
Design, Setting, & Patients
Observational study using administrative data on fee-for-service Medicare beneficiaries 65 years or older undergoing carotid stenting between 2005 and 2007.
Main Outcome Measure
30-day mortality stratified by very-low, low, medium, and high annual operator volumes (<6, 6 to 11, 12 to 23, and ≥24 procedures per year) and treatment early versus late during a new operator’s experience (1st to 11th procedure and 12th procedure or higher).
24,701 procedures were performed by 2339 operators. Of these, 11,846 were performed by 1792 new operators who first performed carotid stenting after its national coverage decision. Overall, 30-day mortality was 1.9% and rate of failure to use an embolic protection device was 4.8%. The median annual operator volume in Medicare beneficiaries was 3.0 per year (IQR, 1.4 to 6.5) and 11.6% of operators performed ≥12 procedures per year during the study period. Observed 30-day mortality was higher among patients treated by operators with lower annual volumes (2.5% [95% CI, 2.1%-2.9%], 1.9% [95% CI, 1.6%-2.3%], 1.6% [95% CI, 1.3%-1.9%], and 1.4% [95% CI, 1.1%-1.7%] across the 4 categories; P<0.001) and among patients treated early versus late during a new operator’s experience (2.3% [95% CI, 2.0%-2.7%] and 1.4% [95% CI, 1.1%-1.9%]; P=0.001). After multivariable adjustment, patients treated by very-low volume operators had a higher risk of 30-day mortality when compared with patients treated by high volume operators (adjusted OR, 1.9; 95% CI, 1.4 to 2.7; P<0.001). Similarly, we found a higher risk of 30-day mortality in patients treated early versus late during a new operator’s experience (adjusted OR, 1.7; 95% CI, 1.2 to 2.4; P=0.001).
Among older patients undergoing carotid stenting, lower annual operator volume and early experience were associated with increased 30-day mortality.
PMCID: PMC3208144  PMID: 21954477
4.  National Performance on Door-In to Door-Out Time Among Patients Transferred for Primary Percutaneous Coronary Intervention 
Archives of internal medicine  2011;171(21):1879-1886.
Delays in treatment time are commonplace for patients with ST-segment elevation acute myocardial infarction who must be transferred to another hospital for per-cutaneous coronary intervention. Experts have recommended that door-in to door-out (DIDO) time(ie, time from arrival at the first hospital to transfer from that hospital to the percutaneous coronary intervention hospital) should not exceed 30 minutes. We sought to describe national performance in DIDO time using a new measure developed by the Centers for Medicare & Medicaid Services.
We report national median DIDO time and examine associations with patient characteristics (age, sex, race, contraindication to fibrinolytic therapy, and arrival time) and hospital characteristics (number of beds, geographic region, location [rural or urban], and number of cases reported) using a mixed effects multivariable model.
Among 13 776 included patients from 1034 hospitals, only 1343 (9.7%) had a DIDO time within 30 minutes, and DIDO exceeded 90 minutes for 4267 patients (31.0%). Mean estimated times (95% CI) to transfer based on multivariable analysis were 8.9 (5.6-12.2) minutes longer for women, 9.1 (2.7-16.0) minutes longer for African Americans, 6.9 (1.6-11.9) minutes longer for patients with contraindication to fibrinolytic therapy, shorter for all age categories (except >75 years) relative to the category of 18 to 35 years, 15.3 (7.3-23.5) minutes longer for rural hospitals, and 14.4 (6.6-21.3) minutes longer for hospitals with 9 or fewer transfers vs 15 or more in 2009 (all P<.001).
Among patients presenting to emergency departments and requiring transfer to another facility for percutaneous coronary intervention, the DIDO time rarely met the recommended 30 minutes.
PMCID: PMC4312661  PMID: 22123793
5.  Clinical Symptoms and Angiographic Findings of Patients Undergoing Elective Coronary Angiography without Prior Stress Testing 
The American journal of cardiology  2014;114(3):348-354.
Many patients undergo elective coronary angiography without pre-procedural stress testing which may be suitable if performed in patients with more angina pectoris or more frequently identified obstructive coronary artery disease (CAD). Patients in the NCDR CathPCI Registry® undergoing elective coronary angiography between July 2009 and April 2013 were assessed for differences in angina (Canadian Cardiovascular Society [CCS] class) and severity of obstructive CAD in those with and without pre-procedural stress testing, stratified by prior CAD history. Given the large sample size, differences were considered clinically meaningful if the standardized difference (SD) was >10%. Of 790,601 patients without prior CAD history, 36.9% did not undergo prior stress testing. Compared to patients with prior stress testing, patients without prior stress testing were more frequently angina free (CCS class 0; 28.2% with stress test vs. 38.5% without, SD=14.8%) and had similar rates of obstructive CAD (40.1% with stress test vs. 35.7% without, SD=9.0). Among 449,579 patients with prior CAD history, 44.2% did not undergo prior stress testing. Patients without prior stress testing reported more angina (CCS Class III/IV angina: 17.8% vs. 13.4%; SD=11.3%) but were not more likely to have obstructive CAD (78.7% vs. 81.1%; SD=5.8%) than patients with prior stress testing. In conclusion, approximately 40% of patients undergoing elective coronary angiography did not have pre-procedural risk stratification with stress testing. For these patients, the clinical decision to proceed directly to invasive evaluation was not driven primarily by severe angina and did not result in higher detection rates for obstructive CAD.
PMCID: PMC4275109  PMID: 24890987
Coronary angiography; stress testing; stable angina
6.  Patient and Hospital Characteristics Associated with Inappropriate Percutaneous Coronary Interventions 
Journal of the American College of Cardiology  2013;62(24):10.1016/j.jacc.2013.07.086.
To examine whether rates of inappropriate PCI differ by demographic characteristics and insurance status.
Prior studies have found that blacks, women and those with public or no health insurance are less likely to undergo percutaneous coronary intervention (PCI). Whether this reflects potential overuse in whites, men, and privately insured patients, in addition to underuse in disadvantaged populations, is unknown.
Within the NCDR® CathPCI Registry®, we identified 221,254 non-acute PCIs performed between July 2009 and March 2011. PCI appropriateness was determined using Appropriate Use Criteria (AUC) for coronary revascularization. Multivariable hierarchical regression models evaluated the association between patient demographics and insurance status with AUC-defined inappropriate PCI.
Of 211,254 non-acute PCIs, 25,749 (12.2%) were classified as inappropriate. After multivariable adjustment, men (adjusted OR, 1.08 [95% CI: 1.05–1.11]; P<0.001) and whites (adjusted OR, 1.09 [1.05–1.14]; P<0.001) were more likely to undergo an inappropriate PCI, compared with women and non-whites. Compared with privately insured patients, those with Medicare (adjusted OR, 0.85 [0.83–0.88]), other public insurance (adjusted OR, 0.78 [0.73–0.83]) and no insurance (adjusted OR, 0.56 [0.50–0.61]) were less likely to undergo an inappropriate PCI (P<0.001). Additionally, compared with urban hospitals, those admitted at rural hospitals were less likely to undergo inappropriate PCI, whereas those at suburban hospitals were more likely.
For non-acute indications, PCIs categorized as inappropriate were more commonly performed in men, patients of white race, and those with private insurance. Higher rates of PCI in these patient populations may be, in part, due to procedural overuse.
PMCID: PMC3864986  PMID: 24055743
7.  Use of a Heart Team in Decision-Making for Patients with Complex Coronary Disease at Hospitals in Michigan Prior to Guideline Endorsement 
PLoS ONE  2014;9(11):e113241.
Revascularization decisions can profoundly impact patient survival, quality of life, and procedural risk. Although use of Heart Teams to make revascularization decisions is growing, data on their implementation in the real-world are limited. Our objective was to assess the prevalence of Heart Teams and their association with collaboration in routine practice.
A survey of cardiologists and cardiac surgeons at 31 hospitals in Michigan was performed in May, 2011 – prior to the recommendation for using Heart Teams in national guidelines. This survey included all percutaneous coronary intervention-performing hospitals in Michigan participating in the Blue Cross/Blue Shield of Michigan Cardiovascular Consortium and Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative. It targeted both the use of Heart Teams and multidisciplinary Case Conferences.
There were 53 physician survey respondents from 27 hospitals with 4 hospitals not responding. Among respondents, 11 (40.7%) hospitals reported no Heart Teams or Case Conferences while 7 (25.9%) hospitals reported either a Heart Team or Case Conference. However, there was disagreement about the presence of a Heart Team at seven hospitals, and about Case Conferences at nine hospitals. Hospitals with definite Heart Teams reported significantly greater levels of collaboration between cardiologists and cardiac surgeons.
The overall presence of Heart Teams prior to their recommendation in national guidelines was limited. Even among hospitals with a potential Heart Team, there was substantial disagreement between respondents about their presence. Further refinement of the definition of a Heart Team and measures of successful implementation are needed.
PMCID: PMC4240646  PMID: 25415332
8.  Association between a Hospital’s Rate of Cardiac Arrest Incidence and Cardiac Arrest Survival 
JAMA internal medicine  2013;173(13):1186-1195.
National efforts to measure hospital performance for cardiac arrest have focused on case survival, with the hope of improving survival after cardiac arrest. However, it is plausible that hospitals with high case-survival rates do a poor job of preventing cardiac arrests in the first place.
To describe the association between inpatient cardiac arrest incidence and survival rates.
Design, Setting, and Patients
Within a large, national registry, we identified hospitals with at least 50 adult in-hospital cardiac arrest cases between January 1, 2000 and November 30, 2009. We used multivariable hierarchical regression to evaluate the correlation between a hospital’s cardiac arrest incidence rate and its case-survival rate after adjusting for patient and hospital characteristics.
Main Outcome Measure
The correlation between a hospital’s incidence rate and case-survival rate for cardiac arrest.
Of 102,153 cases at 358 hospitals, the median hospital cardiac arrest incidence rate was 4.02 per 1000 admissions (IQR: 2.95 to 5.65 per 1000 admissions), and the median hospital case-survival rate was 18.8% (IQR: 14.5% to 22.6%). In crude analyses, hospitals with higher case-survival rates also had lower cardiac arrest incidence (correlation of -0.16; P=0.003). This relationship persisted after adjusting for patient characteristics (correlation of -0.15; P=0.004). After adjusting for potential mediators of this relationship (i.e., hospital characteristics), the relationship between incidence and case-survival was attenuated (correlation of -0.07; P=0.18). The one modifiable hospital factor that most attenuated this relationship was a hospital’s nurse-to-bed ratio (correlation of -0.12; P=0.03).
Hospitals with exceptional rates of survival for in-hospital cardiac arrest are also better at preventing cardiac arrests, even after adjusting for patient case-mix. This relationship is partially mediated by measured hospital attributes. Performance measures focused on case-survival rates appear to be an appropriate first step in quality measurement for in-hospital cardiac arrest.
PMCID: PMC4181325  PMID: 23689900
9.  Risk-Standardizing Survival for In-Hospital Cardiac Arrest to Facilitate Hospital Comparisons 
The purpose of this study is to develop a method for risk-standardizing hospital survival after cardiac arrest.
A foundation with which hospitals can improve quality is to be able to benchmark their risk-adjusted performance against other hospitals, something that cannot currently be done for survival after in-hospital cardiac arrest.
Within the Get With The Guidelines (GWTG)-Resuscitation registry, we identified 48,841 patients admitted between 2007 and 2010 with an in-hospital cardiac arrest. Using hierarchical logistic regression, we derived and validated a model for survival to hospital discharge and calculated risk-standardized survival rates (RSSRs) for 272 hospitals with at least 10 cardiac arrest cases.
The survival rate was 21.0% and 21.2% for the derivation and validation cohorts, respectively. The model had good discrimination (C-statistic 0.74) and excellent calibration. Eighteen variables were associated with survival to discharge, and a parsimonious model contained 9 variables with minimal change in model discrimination. Before risk adjustment, the median hospital survival rate was 20% (interquartile range: 14% to 26%), with a wide range (0% to 85%). After adjustment, the distribution of RSSRs was substantially narrower: median of 21% (interquartile range: 19% to 23%; range 11% to 35%). More than half (143 [52.6%]) of hospitals had at least a 10% positive or negative absolute change in percentile rank after risk standardization, and 50 (23.2%) had a ≥20% absolute change in percentile rank.
We have derived and validated a model to risk-standardize hospital rates of survival for in-hospital cardiac arrest. Use of this model can support efforts to compare hospitals in resuscitation outcomes as a foundation for quality assessment and improvement.
PMCID: PMC3769937  PMID: 23770167
cardiac arrest; risk adjustment; variation in care
10.  Hospital Variation in Survival Trends for In‐hospital Cardiac Arrest 
During the past decade, survival after in‐hospital cardiac arrest has improved markedly. It remains unknown whether the improvement in survival has occurred uniformly at all hospitals or was driven by large improvements at only a few hospitals.
Methods and Results
We identified 93 342 adults with an in‐hospital cardiac arrest at 231 hospitals in the Get With The Guidelines®‐Resuscitation registry during 2000–2010. Using hierarchical regression models, we evaluated hospital‐level trends in survival to discharge. Mean age was 66 years, 59% were men, and 21% were black. Between 2000 and 2010, there was a significant decrease in age, prevalence of heart failure and myocardial infarction, and cardiac arrests due to shockable rhythms (P<0.001 for all) and an increase in prevalence of sepsis, respiratory insufficiency, renal insufficiency, intensive care unit location, and mechanical ventilation before arrest (P<0.001 for all). After adjustment for temporal trends in baseline characteristics, hospital rates of in‐hospital cardiac arrest survival improved by 7% per year (odds ratio [OR] 1.07, 95% CI 1.06 to 1.08, P<0.001). Improvement in survival varied markedly and ranged from 3% in the bottom hospital quartile to 11% in the top hospital quartile. Compared with minor teaching hospitals (OR 1.04, 95% CI 1.02 to 1.06), hospital rate of survival improvement was greater at major teaching (OR 1.08, 95% CI 1.06 to 1.10) and nonteaching hospitals (OR 1.07, 95% CI 1.05 to 1.09, P value for interaction=0.03).
Although in‐hospital cardiac arrest survival has improved during the past decade, the magnitude of improvement varied across hospitals. Future studies are needed to identify hospital processes that have led to the largest improvement in survival.
PMCID: PMC4309112  PMID: 24922627
cardiac arrest; cardiopulmonary resuscitation; health services research; survival
11.  Survival by the Fittest: Hospital‐Level Variation in Quality of Resuscitation Care 
PMCID: PMC3959720  PMID: 24584744
Editorials; cardiac arrest; resuscitation; survival; systems of care
12.  Protocol for a prospective, controlled study of assertive and timely reperfusion for patients with ST-segment elevation myocardial infarction in Tamil Nadu: the TN-STEMI programme 
BMJ Open  2013;3(12):e003850.
Over the past two decades, India has witnessed a staggering increase in the incidence and mortality of ST-elevation myocardial infarction (STEMI). Indians have higher rates of STEMI and younger populations that suffer from it when compared with developed countries. Yet, the recommended reperfusion therapy with fibrinolysis and percutaneous coronary intervention is available only to a minority of patients. This gap in care is a result of financial barriers, limited healthcare infrastructure and poor knowledge and accessibility of acute medical services for a majority of its population.
Methods and analysis
This is a prospective, multicentre, ‘pretest/post-test’ quasi-experimental, community-based study. This programme will use a ‘hub-and-spoke’ model of an integrated healthcare network based on clusters of primary-care health clinics, small hospitals and large tertiary-care facilities. It is an ‘all-comers’ study which will enrol consecutive patients presenting with STEMI to the participating hospitals. The primary objectives of the study is to improve the use of reperfusion therapy and reduce the time from first medical contact to device or drug in STEMI patients; and to increase the rates of early invasive risk stratification with coronary angiography within 3–24 h of fibrinolytic therapy in eligible patients through changes in process of care. Outcomes will be measured with statistical comparison made before and after implementing the TN-STEMI programme. The estimated sample size is based on the Kovai Erode Pilot study, which provided an initial work on establishing this type of programme in South India. It will be adequately powered at 80% with a superiority margin of 10% if 36 patients are enrolled per cluster or 108 patients in three clusters. Thus, the enrolment period of 9 months will result in a sample size of 1500 patients.
This study will be conducted in accordance with the ethical principles that have their origin in the current Declaration of Helsinki and ‘ethical guidelines for biomedical research on human participants’ as laid down by the Indian Council for Medical Research. All participating hospitals will still obtain local ethics committee approval of the study protocol and written informed consent will be obtained from all participants.
Dissemination and results
Our findings will be reported through scientific publications, research conferences and public policy venues aimed at state and local governments in India. If successful, this model can be extended to other areas of India as well as serve as a model of STEMI systems of care for low-income and middle-income countries across the world.
Trial is registered with Clinical trial registry of India, No: CTRI/2012/09/003002.
PMCID: PMC3855601  PMID: 24302505
13.  Use and Effectiveness of Intra-Aortic Balloon Pumps Among Patients Undergoing High Risk Percutaneous Coronary Intervention: Insights from the NCDR® 
IABPs are frequently used to provide hemodynamic support during high risk percutaneous coronary intervention (PCI), but clinical evidence to support their use is mixed. We examined hospital variation in IABP use among high risk PCI patients, and determined the association of IABP use on mortality in this population.
Methods and Results
We analyzed data submitted to the CathPCI Registry® between January 2005 and December 2007. High risk PCI was defined as having at least one of the following features: unprotected left main artery as the target vessel, cardiogenic shock, severely depressed left ventricular function, or ST segment elevation myocardial infarction. Hospitals were categorized into quartiles by their proportional use of IABP. We examined differences in in-hospital mortality across hospital quartiles using a hierarchical logistic regression model to adjust for differences in patient and hospital characteristics across hospital quartiles of IABP use. IABPs were used in 18,990 (10.5%) of 181,599 high risk PCIs. Proportional use of IABP varied significantly across hospital quartiles: Q1: 0.0%–6.5%; Q2: 6.6% to 9.2%; Q3: 9.3% to 14.1%; and Q4: 14.2% to 40.0%. In multivariable analysis, after adjustment for differences in patient and hospital characteristics, in-hospital mortality was comparable across quartiles of hospital IABP usage (Q1: Ref; Q2: Odds Ratio (OR) 1.11, 95% CI 0.99–1.24; Q3: OR 1.03, 95% CI 0.92–1.15; Q4: OR 1.06, 95% CI 0.94–1.18).
IABP use varied significantly across hospitals for high risk PCI. However, this variation in IABP use was not associated with differences in in-hospital mortality.
PMCID: PMC3801197  PMID: 22147887
Angioplasty; Atherosclerosis; Heart assist device
14.  Long-Term Outcomes in Elderly Survivors of In-Hospital Cardiac Arrest 
The New England journal of medicine  2013;368(11):1019-1026.
Little is known about the long-term outcomes in elderly survivors of in-hospital cardiac arrest. We determined rates of long-term survival and readmission among survivors of in-hospital cardiac arrest and examined whether these outcomes differed according to demographic characteristics and neurologic status at discharge.
We linked data from a national registry of inpatient cardiac arrests with Medicare files and identified 6972 adults, 65 years of age or older, who were discharged from the hospital after surviving an in-hospital cardiac arrest between 2000 and 2008. Predictors of 1-year survival and of readmission to the hospital were examined.
One year after hospital discharge, 58.5% of the patients were alive, and 34.4% had not been readmitted to the hospital. The risk-adjusted rate of 1-year survival was lower among older patients than among younger patients (63.7%, 58.6%, and 49.7% among patients 65 to 74, 75 to 84, and ≥85 years of age, respectively; P<0.001), among men than among women (58.6% vs. 60.9%, P = 0.03), and among black patients than among white patients (52.5% vs. 60.4%, P = 0.001). The risk-adjusted rate of 1-year survival was 72.8% among patients with mild or no neurologic disability at discharge, as compared with 61.1% among patients with moderate neurologic disability, 42.2% among those with severe neurologic disability, and 10.2% among those in a coma or vegetative state (P<0.001 for all comparisons). Moreover, 1-year readmission rates were higher among patients who were black, those who were women, and those who had substantial neurologic disability (P<0.05 for all comparisons). These differences in survival and readmission rates persisted at 2 years. At 3 years, the rate of survival among survivors of in-hospital cardiac arrest was similar to that of patients who had been hospitalized with heart failure and were discharged alive (43.5% and 44.9%, respectively; risk ratio, 0.98; 95% confidence interval, 0.95 to 1.02; P = 0.35).
Among elderly survivors of in-hospital cardiac arrest, nearly 60% were alive at 1 year, and the rate of 3-year survival was similar to that among patients with heart failure. Survival and readmission rates differed according to the demographic characteristics of the patients and neurologic status at discharge. (Funded by the American Heart Association and the National Heart, Lung, and Blood Institute.)
PMCID: PMC3652256  PMID: 23484828
16.  Exposure to Low-Dose Ionizing Radiation from Medical Imaging Procedures in the United States 
The New England journal of medicine  2009;361(9):849-857.
Growing use of imaging procedures in the United States has raised concerns about exposure to low-dose ionizing radiation in the general population.
We identified 952,420 non-elderly adults in 5 healthcare markets across the United States between July 1, 2005 and December 31, 2007. Utilization data were used to determine cumulative effective doses of radiation from imaging procedures in millisieverts (mSv) and to calculate population-based rates of “moderate” (>3 to 20 mSv per year), “high” (>20 to 50 mSv per year) and “very-high” (>50 mSv per year) doses.
During the study period, 655,613 (68.8%) individuals underwent at least 1 imaging procedure associated with radiation exposure. The mean effective dose from imaging procedures was 2.4 mSv per person per year (std dev, 6.0 mSv); however, a wide distribution was noted with a median effective dose of 0.1 mSv per person per year (interquartile range, 0.0 to 1.7). Overall, the annual rate for moderate effective doses in the study population was 193.8 per 1000 enrollees, while high and very-high doses occurred at annual rates of 18.6 per 1000 enrollees and 1.9 per 1000 enrollees, respectively. In general, effective doses of radiation from imaging procedures increased with advancing age and were higher in women. Computed tomography and nuclear medicine scans accounted for 75.4% of the total effective dose and 81.8% occurred in non-hospitalized settings.
Imaging procedures are an important source of ionizing radiation in the United States and can lead to high radiation doses in patients.
PMCID: PMC3707303  PMID: 19710483
17.  Use of Medical Imaging Procedures With Ionizing Radiation in Children: A Population-Based Study 
To determine population-based rates of use of diagnostic imaging procedures with ionizing radiation in children, stratified by age and gender.
Retrospective cohort analysis.
All settings utilizing imaging procedures with ionizing radiation.
Individuals less than 18 years old, alive and continuously enrolled in Unitedhealthcare between January 1, 2005 and December 31, 2007 in 5 large U.S. healthcare markets.
Main Outcome Measure
Number and type of diagnostic imaging procedures utilizing ionizing radiation in children.
355,088 children were identified. A total of 436,711 imaging procedures using ionizing radiation were performed in 150,930 (42.5%) patients. The highest rates of use were in children greater than 10 years old, with frequent use in infants under 2 years old as well. Plain radiography accounted for nearly 85% of imaging procedures performed. Computed tomography (CT) scans – associated with substantially higher doses of radiation – were commonly used, accounting for 12% of all procedures during the study period. Overall, 7.9% of children received at least one CT and 3.5% received 2 or more, with CT of the head most frequent.
Exposure to ionizing radiation from medical diagnostic imaging procedures may occur frequently among children. Efforts to optimize and ensure appropriate use of these procedures in the pediatric population should be encouraged.
PMCID: PMC3686496  PMID: 21199972
18.  Trends in Survival After In-Hospital Cardiac Arrest 
The New England journal of medicine  2012;367(20):1912-1920.
Despite numerous advances in resuscitation care in recent years, it remains unknown whether survival and neurological function after in-hospital cardiac arrest has improved over time.
We identified all adults with an index in-hospital cardiac arrest at 374 hospitals in the Get With The Guidelines-Resuscitation registry between 2000 and 2009. Using multivariable regression, we examined temporal trends in risk-adjusted rates of survival to discharge. Additional analyses explored whether trends: (1) were due to improved survival during the acute resuscitation or post-resuscitation care and (2) occurred at the expense of greater neurological disability among survivors.
Among 84,625 hospitalized patients with cardiac arrest, 67,135 (79.3%) had an initial rhythm of asystole or pulseless electrical activity while 17,490 (20.7%) had ventricular fibrillation or pulseless ventricular tachycardia. The proportion of cardiac arrests due to asystole or pulseless electrical activity increased over time (P for trend <0.001). Risk-adjusted rates of survival to discharge in the overall cohort increased from 13.7% in 2000 to 22.4% in 2009 (adjusted rate-ratio per 1-year: 1.04, 95% CI [1.02–1.05]; P for trend <0.001). Survival improvement was similar in both rhythm groups and largely due to improved survival from the acute resuscitation (risk-adjusted rates: 42.7% in 2000, 54.1% in 2009; adjusted rate-ratio per 1-year: 1.03, 95% CI [1.02–1.04]; P for trend <0.001). Importantly, rates of neurological disability among survivors decreased over time (risk-adjusted rates: 32.9% in 2000, 28.1% in 2009; P for trend=0.02).
Both survival and neurological outcomes after in-hospital cardiac arrest have improved over the past decade.
PMCID: PMC3517894  PMID: 23150959
19.  Duration of resuscitation efforts and subsequent survival after in-hospital cardiac arrest 
Lancet  2012;380(9852):1473-1481.
During in-hospital cardiac arrests, it is uncertain how long resuscitation should continue prior to termination of efforts. We hypothesized that the duration of resuscitation varies across hospitals, and that patients at hospitals with longer attempts have higher survival rates.
Between 2000 and 2008, we identified 64,339 patients with cardiac arrests at 435 hospitals within a large national registry. For each hospital, we calculated the median duration of resuscitation before termination of efforts among its non-survivors as a measure of the hospital’s overall tendency for longer attempts. We then determined the association between a hospital’s tendency for longer attempts and risk-adjusted survival using multilevel regression models.
The overall proportion of patients achieving immediate survival with return of spontaneous circulation (ROSC) was 48·5% while 15·4% survived to discharge. For patients achieving ROSC, the median resuscitation time was 12 minutes (IQR: 6–21) while it was 20 minutes (IQR: 14–30) for those not achieving ROSC (i.e., non-survivors). Compared with patients at hospitals with the shortest attempts (median duration, 16 minutes), patients at hospitals with the longest attempts (median duration, 25 minutes) had a higher likelihood of ROSC (adjusted risk-ratio 1·12, [95% CI: 1·06–1·18]; p <0·001) and survival to discharge (adjusted risk-ratio 1·12, [95% CI: 1·02–1·23]; p=0·021). These findings were more prominent in cardiac arrests due to asystole and pulseless electrical activity (p for interaction<0.01 for both ROSC and survival to discharge).
The duration of resuscitation attempts varies across hospitals. Patients at hospitals with longer attempts have a higher likelihood of ROSC and survival to discharge, particularly when the arrest is due to asystole and pulseless electrical activity.
The American Heart Association, the Robert Wood Johnson Foundation Clinical Scholars Program, the National Institutes of Health.
PMCID: PMC3535188  PMID: 22958912
20.  Improvements in Door-to-Balloon Time in the United States: 2005-2010 Krumholz: Trends in D2B Time: 2005-2010 
Circulation  2011;124(9):1038-1045.
Registry studies have suggested improvements in door-to-balloon times, but a national assessment of the trends in door-to-balloon times is lacking. Moreover, we do not know if improvements in door-to-balloon times were shared equally among patient and hospital groups.
Methods and Results
This analysis includes all patients reported by hospitals to the Centers for Medicare & Medicaid Services for inclusion in the time to percutaneous coronary intervention acute myocardial infarction-8 (AMI-8) inpatient measure from January 1, 2005 through September 30, 2010. For each calendar year, we summarized the characteristics of patients reported for the measure including the number and percentage in each group as well as the median time to primary percutaneous coronary intervention, and the percentage with time to primary percutaneous coronary intervention within 75 minutes and within 90 minutes. Door-to-balloon time declined from a median of 96 minutes in the year ending December 31, 2005 to a median of 64 minutes in the three quarters ending September 30, 2010. There were corresponding increases in the percentage of patients who had times <90 minutes (44.2% to 91.4%) and <75 minutes (27.3% to 70.4%). The declines in median times were greatest among groups that had the highest median times during the first period: Patients >75 years of age (median decline 38 minutes); women (35 minutes); and African Americans (42 minutes).
National progress has been achieved in the treatment of patients with ST-segment elevation myocardial infarction who undergo primary percutaneous coronary intervention.
PMCID: PMC3598634  PMID: 21859971
percutaneous coronary intervention; myocardial infarction; balloon; reperfusion
21.  Automated External Defibrillators and Survival After In-Hospital Cardiac Arrest 
Automated external defibrillators (AEDs) improve survival from out-of-hospital cardiac arrests, but data on their effectiveness in hospitalized patients are limited.
To evaluate the association of AED use and survival for in-hospital cardiac arrest.
Design, Setting, Patients
Cohort study of 11,695 hospitalized patients with cardiac arrests between January 1, 2000 and August 26, 2008 at 204 hospitals following the introduction of AEDs on general hospital wards.
Main Outcome Measure
Survival to hospital discharge by AED use, using multivariable hierarchical regression analyses to adjust for patient factors and hospital site.
Of 11,695 patients, 9616 (82.2%) had non-shockable rhythms (asystole and pulseless electrical activity) and 2079 (17.8%) had shockable rhythms (ventricular fibrillation and pulseless ventricular tachycardia). AEDs were used in 4515 (38.6%) patients. Overall, 2117 (18.1%) patients survived to hospital discharge. Within the entire study population, AED use was associated with a lower rate of survival after in-hospital cardiac arrest compared with no AED use (16.3% vs. 19.3%; adjusted rate ratio (RR), 0.85; 95% confidence interval (CI), 0.78–0.92; P<0.001). Among cardiac arrests due to non-shockable rhythms, AED use was associated with lower survival (10.4% vs. 15.4%; adjusted RR, 0.74; 95% CI, 0.65–0.83; P<.001). In contrast, for cardiac arrests due to shockable rhythms, AED use was not associated with survival (38.4% vs. 39.8%; adjusted RR, 1.00; 95% CI, 0.88–1.13; P=0.99). These patterns were consistently observed in both monitored and non-monitored hospital units where AEDs were used, after matching patients to the individual units in each hospital where the cardiac arrest occurred, and with a propensity score analysis.
Use of AEDs in hospitalized patients with cardiac arrest is not associated with improved survival.
PMCID: PMC3587791  PMID: 21078809
22.  Variation in the Use of Lower Extremity Vascular Procedures for Critical Limb Ischemia 
Many believe that variation in vascular practice may affect limb salvage rates in patients with severe PAD. However, the extent of variation in procedural vascular care obtained by patients with critical limb ischemia (CLI) remains unknown.
Methods and Results
Using Medicare 2003–2006, we identified all patients with CLI who underwent major lower extremity amputation in the 306 hospital referral regions (HRRs) described in the Dartmouth Atlas of Healthcare. For each patient, we studied the use of lower extremity vascular procedures (open surgery or endovascular intervention) in the year prior to amputation. Our main outcome measure was the intensity of vascular care, defined as the proportion of patients in the HRR undergoing vascular procedure in the year before amputation. Overall, 20,464 patients with CLI underwent major lower extremity amputations during the study period, and collectively underwent 25,800 vascular procedures in the year prior to undergoing amputation. However, these procedures were not distributed evenly − 54% of patients had no vascular procedures performed in the year prior to amputation, 14% underwent 1 vascular procedure, and 21% underwent more than one vascular procedure. In the regions in the lowest quintile of vascular intensity, vascular procedures were performed in 32% of patients. Conversely, in the regions in the highest quintile of vascular intensity, revascularization was performed in 58% of patients in the year prior to amputation (p<0.0001). In analyses accounting for differences in age, sex, race, and comorbidities, patients in high intensity regions were 2.4 times as likely to undergo revascularization in the year prior to amputation than patients in low intensity regions (adjusted OR=2.4, 95% CI 2.1–2.6, p<0.001).
Significant variation exists in the intensity of vascular care provided to patients in the year prior to major amputation. In some regions, patients receive intensive care, while in other regions, far less vascular care is provided. Future work is needed to determine the association between intensity of vascular care and limb salvage.
PMCID: PMC3281555  PMID: 22147886
epidemiology; outcomes research; peripheral vascular disease; treatment disparities; vascular disease
23.  A Validated Prediction Tool for Initial Survivors of In-Hospital Cardiac Arrest 
Archives of internal medicine  2012;172(12):947-953.
Accurate estimation of favorable neurological survival after in-hospital cardiac arrest could provide critical information for physicians, patients, and families.
Within the Get With The Guidelines-Resuscitation registry, we identified 42,957 patients from 551 hospitals admitted between January 2000 and October 2009 who were successfully resuscitated from an in-hospital cardiac arrest. A simple prediction tool for favorable neurological survival in patients successfully resuscitated from an in-hospital cardiac arrest was developed using multivariable logistic regression, with two-thirds of the sample randomly selected as the derivation cohort and one-third as the validation cohort. Favorable neurological status was defined as the absence of severe neurological deficits (Cerebral Performance Category score of ≤2).
Rates of favorable neurological survival were similar in the derivation (n=7052; 24.6%) and validation cohorts (n=3510; 24.5%). Eleven variables were associated with favorable neurological survival: younger age, initial cardiac arrest rhythm of ventricular fibrillation or pulseless ventricular tachycardia with a defibrillation time of ≤2 minutes, baseline neurological status without disability, arrest location in a monitored unit, shorter duration of resuscitation, and absence of mechanical ventilation, renal insufficiency, hepatic insufficiency, sepsis, malignancy, and hypotension prior to the arrest. The model had excellent discrimination (C statistic of 0.80 for both the derivation and validation cohorts) and calibration. The prediction tool demonstrated the ability to identify patients across a wide range of rates of favorable neurological survival: patients in the top decile had a 70.7% probability of this outcome while patients in the bottom decile had a 2.8% probability.
Among successfully resuscitated patients with an in-hospital cardiac arrest, a simple, bedside prediction tool provides robust estimates of the probability of favorable neurological survival. This tool permits accurate prognostication after cardiac arrest for physicians, patients, and families.
PMCID: PMC3517176  PMID: 22641228
Prediction; Risk Score; Cardiac Arrest; Survival; Neurological Disability
24.  Hospital PCI Appropriateness and In-Hospital Procedural Outcomes: Insights from the NCDR® 
Measurement of hospital quality has traditionally focused on processes of care and post-procedure outcomes. Appropriateness measures for percutaneous coronary intervention (PCI) assess quality as it relates to patient selection in the context of anticipated benefits relative to potential harm. The association, if any, between patient selection for PCI and processes of care and post-procedural outcomes is unknown. Defining whether these measures are redundant or complementary can inform the optimal range of metrics for monitoring quality.
We included patients undergoing non-acute (elective) PCI within the NCDR CathPCI Registry® between July 2009 and April 2011. We examined the association between a hospital’s proportion of non-acute PCIs categorized as inappropriate by the 2009 Appropriate Use Criteria (AUC) for Coronary Revascularization and in-hospital mortality, bleeding complications, and use of optimal guideline-directed medical therapy at discharge (i.e. aspirin, thienopyridines, and statins).
A total of 203,531 non-acute PCIs from 779 hospitals were classified by the AUC. Of these, 101,779 (50.0%) were classified as appropriate, 77,220 (35.5%) as uncertain, and 24,532 (12.1%) as inappropriate. When categorized as hospital tertiles, the range of inappropriate PCI was 0.0 to 8.1% in the lowest-tertile, 8.1 to 15.2% in the middle-tertile, and 15.2 to 58.6% in the highest-tertile. Compared with lowest-tertile hospitals, mortality was not significantly different at middle-tertile (adjusted odds ratio [OR] 0.93; 95% confidence interval [CI] 0.73 to 1.19) or highest-tertile hospitals (OR 1.12; 95% CI 0.88 to 1.43; p=0.35 for differences between any tertile). Similarly, risk-adjusted bleeding did not vary significantly (middle-tertile OR 1.13; 95% CI 1.02 to 1.16; highest-tertile OR 1.02; 95% CI 0.91 to 1.16; p=0.07 for differences between any tertile) nor did use of optimal therapy at discharge after PCI (85.3% vs. 85.7% vs. 85.2%; P=0.58).
In a national cohort of non-acute PCIs, a hospital’s proportion of inappropriate PCIs was not associated with in-hospital mortality, bleeding, or medical therapy at discharge. These findings suggest that PCI appropriateness measures aspects of hospital PCI quality that are independent of, and complementary to, traditional quality metrics.
PMCID: PMC3520092  PMID: 22576845
Appropriateness criteria; Coronary artery disease; Percutaneous coronary intervention; Utilization; Hospital; Quality of care; Health services research

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