Determinants of the use of coronary angiography and revascularization after thrombolysis for acute myocardial infarction

Exploring the Intersection of Dementia and Myocardial Infarction: Vascular Perspectives

Emerging evidence underscores the relationship between myocardial infarction and dementia, implicating a profound influence on patient health. The bidirectional relationship between myocardial infarction and dementia is highlighted by pathophysiological changes in vasculature function, lifestyle factors, and environmental influences. Our literature review aims to explore the complex relationship between these 2 pathologies and highlight the pathways by which they mutually influence each other.

Tenecteplase versus alteplase in treatment of acute ST-segment elevation myocardial infarction: A randomized non-inferiority trial

BACKGROUND

A phase II trial on recombinant human tenecteplase tissue-type plasminogen activator (rhTNK-tPA) has previously shown its preliminary efficacy in ST elevation myocardial infarction (STEMI) patients. This study was designed as a pivotal postmarketing trial to compare its efficacy and safety with rrecombinant human tissue-type plasminogen activator alteplase (rt-PA) in Chinese patients with STEMI.

METHODS

In this multicenter, randomized, open-label, non-inferiority trial, patients with acute STEMI were randomly assigned (1:1) to receive an intravenous bolus of 16 mg rhTNK-tPA or an intravenous bolus of 8 mg rt-PA followed by an infusion of 42 mg in 90 min. The primary endpoint was recanalization defined by thrombolysis in myocardial infarction (TIMI) flow grade 2 or 3. The secondary endpoint was clinically justified recanalization. Other endpoints included 30-day major adverse cardiovascular and cerebrovascular events (MACCEs) and safety endpoints.

RESULTS

From July 2016 to September 2019, 767 eligible patients were randomly assigned to receive rhTNK-tPA ( n = 384) or rt-PA ( n = 383). Among them, 369 patients had coronary angiography data on TIMI flow, and 711 patients had data on clinically justified recanalization. Both used a -15% difference as the non-inferiority efficacy margin. In comparison to rt-PA, both the proportion of patients with TIMI grade 2 or 3 flow (78.3% [148/189] vs. 81.7% [147/180]; differences: -3.4%; 95% confidence interval [CI]: -11.5%, 4.8%) and clinically justified recanalization (85.4% [305/357] vs. 85.9% [304/354]; difference: -0.5%; 95% CI: -5.6%, 4.7%) in the rhTNK-tPA group were non-inferior. The occurrence of 30-day MACCEs (10.2% [39/384] vs. 11.0% [42/383]; hazard ratio: 0.96; 95% CI: 0.61, 1.50) did not differ significantly between groups. No safety outcomes significantly differed between groups.

CONCLUSION

rhTNK-tPA was non-inferior to rt-PA in the effect of improving recanalization of the infarct-related artery, a validated surrogate of clinical outcomes, among Chinese patients with acute STEMI.

TRIAL REGISTRATION

www.ClinicalTrials.gov (No. NCT02835534).

Effect of hospital assignment on mortality for AMI patients

BACKGROUND

International guidelines recommend percutaneous coronary intervention (PCI) to treat acute myocardial infarction (AMI) if PCI can be performed within two hours. PCI is a centralized treatment, and therefore a common trade-off is whether to send AMI patients directly to a hospital that performs PCI, or postpone a potential PCI-treatment by first receiving acute treatment at a local hospital that can not perform PCI. In this paper, we estimate the effect of sending patients directly to a PCI-hospital on AMI mortality.

METHODS

Using nation-wide individual-level data from 2010 to 2015, we studied mortality rates for AMI patients sent directly to a hospital that performs PCI (N=20 336) compared to AMI patients sent to a hospital not performing PCI (N=33 437). Since the underlying health of patients may affect both hospital assignment and mortality, estimates from traditional multivariate risk adjustment models are likely biased. We therefore apply an instrumental variable (IV) model using the historical municipal share sent directly to a PCI-hospital as an instrument for being sent directly to a PCI-hospital.

RESULTS

Patients sent directly to a PCI-hospital are younger and have fewer comorbidities than patients who are first sent to a non-PCI-hospital. IV results suggest that those initially sent to PCI-hospitals have 4.8 percentage points decrease (95% CI (- 18.1)-8.5) in mortality after one month compared to those initially sent to non-PCI-hospitals.

CONCLUSION

Our IV results suggest that there is a non-significant decrease in mortality for AMI patients sent directly to a PCI hospital. The estimates are too imprecise to conclude that health personnel should change their practice and send more patients directly to a PCI-hospital. Moreover, the results may be taken to suggest that health personnel navigate AMI patients to the best treatment option.

Prognostic value of shock index in patients admitted with non-ST-segment elevation myocardial infarction: the ARIC study community surveillance

AIMS

Shock index (SI), defined as the ratio of heart rate (HR) to systolic blood pressure (SBP), is easily obtained and predictive of mortality in patients with ST-segment elevation myocardial infarction. However, large-scale evaluations of SI in patients with non-ST-segment elevation myocardial infarction (NSTEMI) are lacking.

METHODS AND RESULTS

Hospitalizations for acute myocardial infarction were sampled from four US areas by the Atherosclerosis Risk in Communities (ARIC) study and classified by physician review. Shock index was derived from the HR and SBP at first presentation and considered high when ≥0.7. From 2000 to 2014, 18 301 weighted hospitalizations for NSTEMI were sampled and had vitals successfully obtained. Of these, 5753 (31%) had high SI (≥0.7). Patients with high SI were more often female (46% vs. 39%) and had more prevalent chronic kidney disease (40% vs. 32%). TIMI (Thrombolysis in Myocardial Infarction) risk scores were similar between the groups (4.3 vs. 4.2), but GRACE (Global Registry of Acute Coronary Syndrome) score was higher with high SI (140 vs. 118). Angiography, revascularization, and guideline-directed medications were less often administered to patients with high SI, and the 28-day mortality was higher (13% vs. 5%). Prediction of 28-day mortality by SI as a continuous measurement [area under the curve (AUC): 0.68] was intermediate to that of the GRACE score (AUC: 0.87) and the TIMI score (AUC: 0.54). After adjustments, patients with high SI had twice the odds of 28-day mortality (odds ratio = 2.02; 95% confidence interval: 1.46-2.80).

CONCLUSION

The SI is easily obtainable, performs moderately well as a predictor of short-term mortality in patients hospitalized with NSTEMI, and may be useful for risk stratification in emergency settings.

'More than one red herring'? Heterogeneous effects of ageing on health care utilisation

We study the effect of ageing, defined as an extra year of life, on health care utilisation. We disentangle the direct effect of ageing, from other alternative explanations such as the presence of comorbidities and endogenous time to death (TTD) that are argued to absorb the effect of ageing (so-called 'red herring' hypothesis). We exploit individual level end of life data from several European countries that record the use of medicine, outpatient and inpatient care and long-term care. Consistently with the 'red herring hypothesis', we find that corrected TTD estimates are significantly different from uncorrected ones, and their effect size exceeds that of an extra year of life, which in turn is moderated by individual comorbidities. Corrected estimates suggest an overall attenuated effect of ageing, which does not influence outpatient care utilisation. These results suggest the presence of 'more than one red herring' depending on the type of health care examined.

Trends in the Incidence and In-Hospital Outcomes of Patients With Atrial Fibrillation Complicated by Non-ST-Segment Elevation Myocardial Infarction

Atrial fibrillation (AF) can present with non-ST-segment elevation myocardial infarction (NSTEMI). The incidence, characteristics, outcomes, and treatment of this subgroup of patients with AF remains poorly studied. Using data from the National Inpatient Sample database, we (1) compared baseline characteristics of patients with AF with/without NSTEMI, (2) evaluated their outcomes and associated trends over the study period (2004-2013), and (3) evaluated revascularization (by percutaneous coronary intervention or coronary artery bypass graft [CABG]) and the impact on patient outcomes. Of the 3 923 436 patients admitted with a primary diagnosis of AF, 47 785 (1.2%) had a secondary diagnosis of NSTEMI. In this subgroup with AF and NSTEMI, there was a significant trend toward a decrease in mortality ( P = .002), stroke ( P < .001), and gastrointestinal bleeding ( P < .001) during the study period. Compared to unrevascularized patients, revascularized patients were more likely to be younger (72.2 ± 10.2 vs 77.0 ± 11.8 years old, P < .001), male (57.8 vs 42.7%, P < .001), and had a much higher incidence of coronary risk factors. Revascularization was associated with increased survival in multivariable analysis (odds ratio: 0.562, 95% confidence interval: 0.334-0.946, P = .03). In conclusion, among patients admitted with AF, 1.2% were diagnosed with NSTEMI. A minority of patients with AF and NSTEMI underwent revascularization and had better in-hospital outcomes.

Quality of Life and Awareness of Cardiac Rehabilitation Program in People With Cardiovascular Diseases

Objective

To evaluate the level of health-related quality of life (HRQoL), life satisfaction, and their present awareness of cardiac rehabilitation (CR) program in people with cardiovascular diseases.

Methods

A questionnaire survey was completed by 53 patients (mean age, 65.7±11.6 years; 33 men and 20 women) with unstable angina, myocardial infarction, or heart failure. The questionnaire included the Medical Outcome Study 36-item Short-Form Health Survey (MOS SF-36), life domain satisfaction measure (LDSM), and the awareness and degree of using CR program.

Results

The average scores of physical component summary (PCS) and mental component summary (MCS) were 47.7±18.5 and 56.5±19.5, respectively. There were significant differences in physical role (F=4.2, p=0.02), vitality (F=10.7, p<0.001), mental health (F=15.9, p<0.001), PCS (F=3.6, p=0.034), and MCS (F=11.9, p<0.001) between disease types. The average LDSM score was 4.7±1.5. Age and disease duration were negatively correlated with multiple HRQoL areas (p<0.05). Monthly income, ejection fraction, and LDSM were positively correlated with several MOS SF-36 factors (p<0.05). However, the number of modifiable risk factors had no significant correlation with medication. Thirty-seven subjects (69.8%) answered that they had not previously heard about CR program. Seventeen patients (32.1%) reported that they were actively participating in CR program. Most people said that a reasonable cost of CR was less than 100,000 Korean won per month.

Conclusion

CR should focus on improving the physical components of quality of life. In addition, physicians should actively promote CR to cardiovascular disease patients to expand the reach of CR program.

Review: The pathogenesis of type 2 diabetes and cardiovascular disease

Type 2 diabetes mellitus is increasing in prevalence, and is a potent risk factor for the development of atherosclerotic vascular disease and increased risk of adverse cardiovascular events. Approximately 15—25% of patients presenting with ischaemic heart disease have a history of diabetes mellitus. This cohort of patients continues to be at heightened short and long-term risk. This review highlights the many proposed biological drivers that likely play a deterministic role in the cardiovascular outcome of patients with type 2 diabetes mellitus.

Chronic obstructive pulmonary disease (COPD) assessment test scores corresponding to modified Medical Research Council grades among COPD patients

BACKGROUND/AIMS

In assigning patients with chronic obstructive pulmonary disease (COPD) to subgroups according to the updated guidelines of the Global Initiative for Chronic Obstructive Lung Disease, discrepancies have been noted between the COPD assessment test (CAT) criteria and modified Medical Research Council (mMRC) criteria. We investigated the determinants of symptom and risk groups and sought to identify a better CAT criterion.

METHODS

This retrospective study included COPD patients seen between June 20, 2012, and December 5, 2012. The CAT score that can accurately predict an mMRC grade ≥ 2 versus < 2 was evaluated by comparing the area under the receiver operating curve (AUROC) and by classification and regression tree (CART) analysis.

RESULTS

Among 428 COPD patients, the percentages of patients classified into subgroups A, B, C, and D were 24.5%, 47.2%, 4.2%, and 24.1% based on CAT criteria and 49.3%, 22.4%, 8.9%, and 19.4% based on mMRC criteria, respectively. More than 90% of the patients who met the mMRC criteria for the 'more symptoms group' also met the CAT criteria. AUROC and CART analyses suggested that a CAT score ≥ 15 predicted an mMRC grade ≥ 2 more accurately than the current CAT score criterion. During follow-up, patients with CAT scores of 10 to 14 did not have a different risk of exacerbation versus those with CAT scores < 10, but they did have a lower exacerbation risk compared to those with CAT scores of 15 to 19.

CONCLUSIONS

A CAT score ≥ 15 is a better indicator for the 'more symptoms group' in the management of COPD patients.

Precision medicine to improve use of bleeding avoidance strategies and reduce bleeding in patients undergoing percutaneous coronary intervention: prospective cohort study before and after implementation of personalized bleeding risks

OBJECTIVE

To examine whether prospective bleeding risk estimates for patients undergoing percutaneous coronary intervention could improve the use of bleeding avoidance strategies and reduce bleeding.

DESIGN

Prospective cohort study comparing the use of bleeding avoidance strategies and bleeding rates before and after implementation of prospective risk stratification for peri-procedural bleeding.

SETTING

Nine hospitals in the United States.

PARTICIPANTS

All patients undergoing percutaneous coronary intervention for indications other than primary reperfusion for ST elevation myocardial infarction.

MAIN OUTCOME MEASURES

Use of bleeding avoidance strategies, including bivalirudin, radial approach, and vascular closure devices, and peri-procedural bleeding rates, stratified by bleeding risk. Observed changes were adjusted for changes observed in a pool of 1135 hospitals without access to pre-procedural risk stratification. Hospital level and physician level variability in use of bleeding avoidance strategies was examined.

RESULTS

In a comparison of 7408 pre-intervention procedures with 3529 post-intervention procedures, use of bleeding avoidance strategies within intervention sites increased with pre-procedural risk stratification (odds ratio 1.81, 95% confidence interval 1.44 to 2.27), particularly among higher risk patients (2.03, 1.58 to 2.61; 1.41, 1.09 to 1.83 in low risk patients, after adjustment for control sites; P for interaction = 0.05). Bleeding rates within intervention sites were significantly lower after implementation of risk stratification (1.0% v 1.7%; odds ratio 0.56, 0.40 to 0.78; 0.62, 0.44 to 0.87, after adjustment); the reduction in bleeding was greatest in high risk patients. Marked variability in use of bleeding avoidance strategies was observed across sites and physicians, both before and after implementation.

CONCLUSIONS

Prospective provision of individualized bleeding risk estimates was associated with increased use of bleeding avoidance strategies and lower bleeding rates. Marked variability between providers highlights an important opportunity to improve the consistency, safety, and quality of care. Study registration Clinicaltrials.gov NCT01383382.

Do gender and race/ethnicity influence acute myocardial infarction quality of care in a hospital with a large Hispanic patient and provider representation?

Background. Disparities in acute myocardial infarction (AMI) care for women and minorities have been extensively reported in United States but with limited information on Hispanics. Methods. Medical records of 287 (62%) Hispanic and 176 (38%) non-Hispanic white (NHW) patients and 245 women (53%) admitted with suspected AMI to a southern California nonprofit community hospital with a large Hispanic patient and provider representation were reviewed. Baseline characteristics, outcomes (mortality, CATH, PCI, CABG, and use of pertinent drug therapy), and medical insurance were analyzed according to gender, Hispanic and NHW race/ethnicity when AMI was confirmed. For categorical variables, 2 × 2 chi-square analysis was conducted. Odds ratio and 95% confidence interval for outcomes adjusted for gender, race/ethnicity, cardiovascular risk factors, and insurance were obtained. Results. Women and Hispanics had similar drug therapy, CATH, PCI, and mortality as men and NHW when AMI was confirmed (n = 387). Hispanics had less private insurance than NHW (31.4% versus 56.3%, P < 0.001); no significant differences were found according to gender. Conclusions. No differences in quality measures and outcomes were found for women and between Hispanic and NHW in AMI patients admitted to a facility with a large Hispanic representation. Disparities in medical insurance showed no influence on these findings.

Physicians' acquaintance with a new procedure results in higher patient referral: experience of Kosovo in coronary angiography

The first coronary angiography in Kosovo was completed in 2003. We analyzed coronary angiographies performed in our center from October 2003 until October 2009 divided into two 3-year periods.

THE AIMS OF OUR STUDY WERE

to compare the number of coronary angiographies completed in the two periods; to evaluate the prevalence of normal coronary angiographies diagnosed in the first period compared to the second period; and to assess the prevalence of advanced coronary artery disease in the first three years compared to the last three years. This was a prospective angiography study that included 1,139 patients. The first group had 422 patients, who underwent the angiography procedure during the first three years, and the second group had 717 patients that went through the procedure during the last three years. In the first year, 109 coronary angiographies were completed, followed by 137, 176, 213, 218 and 286 (P<0.001) procedures in the subsequent years. In the first period, a normal or near-normal coronary artery profile was found in 27% of patients, while this figure rose to approximately 39% in the second period (P=0.004). Advanced coronary artery disease was found in 45% of the patients who underwent coronary angiography during the first three years, whereas this figure was only 24% of cases during the second period (P<0.001). We believe that the availability of specialized resources and the physicians' familiarity with coronary angiography in our country influenced their decision to refer more patients for this procedure.

A simple classification model for hospital mortality in patients with acute lung injury managed with lung protective ventilation

OBJECTIVE

Despite improvements in the care of critically ill patients, hospital mortality rate for acute lung injury remains high at approximately 40%. We developed a classification rule to stratify mechanically ventilated patients with acute lung injury according to hospital mortality and compared this rule with the Acute Physiology and Chronic Health Evaluation III prediction.

PATIENTS

We used data of 2,022 participants in Acute Respiratory Distress Syndrome Network trials to build a classification rule based on 54 variables collected before randomization.

DESIGN

We used a classification tree approach to stratify patients according to hospital mortality using a training subset of 1800 participants and estimated expected prediction errors using tenfold crossvalidation. We validated our classification tree using a subset of 222 participants not included in model building and calculated areas under the receiver operating characteristic curves.

MEASUREMENTS AND MAIN RESULTS

We identified combinations of age (>63 yrs), blood urea nitrogen (>15 mg/dL), shock, respiratory rate (>21 breaths/min), and minute ventilation (>13.9 L/min) as important predictors of hospital mortality at 90 days. The classification tree had a similar expected prediction error in the training set (28% vs. 26%; p = .18) and areas under the receiver operating characteristic curve in the validation set (0.71 vs. 0.73; p = .71) as did a model based on Acute Physiology and Chronic Health Evaluation III.

CONCLUSIONS

Our tree-based classification rule performed similarly to Acute Physiology and Chronic Health Evaluation III in stratifying patients according to hospital mortality, is simpler to use, contains risk factors that may be specific to acute lung injury, and identified minute ventilation as a potential novel predictor of death in patients with acute lung injury.

Severity of asthma score predicts clinical outcomes in patients with moderate to severe persistent asthma

BACKGROUND

The severity of asthma (SOA) score is based on a validated disease-specific questionnaire that addresses frequency of asthma symptoms, use of systemic corticosteroids, use of other asthma medications, and history of hospitalization/intubation for asthma. SOA does not require measurements of pulmonary function. This study compared the ability of SOA to predict clinical outcomes in the EXCELS (Epidemiological Study of Xolair [omalizumab]: Evaluating Clinical Effectiveness and Long-term Safety in Patients with Moderate to Severe Asthma) patient population vs three other asthma assessment tools. EXCELS is a large, ongoing, observational study of patients with moderate to severe persistent asthma and reactivity to perennial aeroallergens.

METHODS

Baseline scores for SOA, asthma control test (ACT), work productivity and impairment index-asthma (WPAI-A), and FEV(1) % predicted were compared for their ability to predict five prespecified adverse clinical outcomes in asthma: serious adverse events (SAEs) reported as exacerbations, SAEs leading to hospitalizations, the incidence of unscheduled office visits, ED visits, and po or IV corticosteroid bursts related to asthma. Logistic regression analysis, area under receiver operating characteristic curves (AUCROCs), and classification and regression tree (CART) analysis were used to evaluate the ability of the four tools to predict adverse clinical outcomes using baseline and 1-year data from 2,878 patients enrolled in the non-omalizumab cohort of EXCELS.

RESULTS

SOA was the only assessment tool contributing significantly in all five statistical models of adverse clinical outcomes by logistic regression analysis (full model AUCROC range, 0.689-0.783). SOA appeared to be a stand-alone predictor for four of five outcomes (reduced model AUCROC range, 0.689-0.773). CART analysis showed that SOA had the greatest variable importance for all five outcomes.

CONCLUSIONS

SOA score was a powerful predictor of adverse clinical outcomes in moderate to severe asthma, as evaluated by either logistic regression analysis or CART analysis.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00252135; URL: www.clinicaltrials.gov.

Prognosis after change in left ventricular ejection fraction during mental stress testing in patients with stable coronary artery disease

Previous studies of patients with stable coronary artery disease have demonstrated that decreases in the left ventricular ejection fraction (LVEF) during acute mental stress are predictive of adverse clinical outcomes. The aim of the present study was to examine the prospective relation of mental stress on clinical outcomes in a sample of 138 patients with stable coronary artery disease. Patients underwent mental stress testing and were followed for a median of 5.9 years to assess the occurrence of the combined end point of myocardial infarction or all-cause mortality. There were 32 events (17 nonfatal myocardial infarctions and 15 deaths) over the follow-up period. Of the 26 patients who exhibited myocardial ischemia during mental stress testing, 11 (42%) sustained subsequent clinical events, compared to 21 of the 112 patients (19%) who showed no mental stress-induced ischemia. LVEF change during mental stress was also related to the clinical events in a graded, continuous fashion, with each 4% decrease from the LVEF at rest associated with an adjusted hazard ratio of 1.7, (95% confidence interval 1.1 to 2.6, p = 0.011). In conclusion, reductions in the LVEF during mental stress are prospectively associated with adverse clinical outcomes.

Determinants of cardiac catheterization use in older Medicare patients with acute myocardial infarction

BACKGROUND

Cardiac catheterization is substantially underused among higher-risk patients with acute myocardial infarction (AMI) with appropriate indications but overused among patients with inappropriate indications. We sought to determine the importance of anticipated benefit and anticipated harm on the use of cardiac catheterization among older patients with AMI.

METHODS AND RESULTS

We performed an analysis of Medicare fee-for-service beneficiaries hospitalized with an AMI between 1998 and 2001. Multivariate models were developed to determine relative importance of anticipated benefit (baseline cardiovascular risk), anticipated harm (bleeding risk, comorbidities), and demographic factors (age, sex, race, regional invasive intensity) in predicting cardiac catheterization use within 60 days of AMI admission. Analyses were stratified by American College of Cardiology/American Heart Association class I or II as appropriate, and class III as inappropriate. Determinants of reduced likelihood of cardiac catheterization among 42 241 AMI patients with appropriate indications included (in order of importance) older age (likelihood chi(2)=1309.5), higher bleeding risk score (likelihood chi(2)=471.2), more comorbidities (likelihood chi(2)=276.6), female sex (likelihood chi(2)=162.9), hospitalization in low (likelihood chi(2)=67.9) or intermediate intensity invasive regions (likelihood chi(2)=22.4) (all P<0.001), and baseline cardiovascular risk (likelihood chi(2)=6.4, P=0.01). Among 2398 AMI patients with inappropriate indications, significant determinants of greater procedure likelihood included younger age, male sex, lower bleeding risk score, and fewer comorbidities.

CONCLUSIONS

Regardless of the procedure indication, the decision to perform cardiac catheterization in this population appears largely driven by demographic factors and potential harm rather than potential benefit of the procedure.

The paradoxical use of cardiac catheterization in patients with non-ST-elevation acute coronary syndromes: lessons from the Can Rapid Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC /AHA Guidelines (CRUSADE) Quality Improvement Initiative

BACKGROUND

The long-term benefits of coronary revascularization are proportional to the severity of underlying coronary artery disease (CAD). We sought to identify patients with a greater probability of severe CAD to target those who could receive the greatest benefit from revascularization.

METHODS

We used multivariable logistic generalized estimating equations modeling to identify clinical factors associated with severe CAD in 83,490 patients, without prior bypass surgery, who underwent coronary angiography after presenting with non-ST-segment elevation acute coronary syndromes enrolled in CRUSADE. We then compared actual patterns of cardiac catheterization use relative to patients' probability of severe CAD in those who underwent catheterization and those who did not.

RESULTS

Independent factors associated with severe CAD included older age, male sex, diabetes, no prior percutaneous coronary intervention, signs or history of heart failure, prior myocardial infarction, ST-segment depression, and family history of CAD. Cardiac catheterization rates were inversely related to the probability of severe CAD as estimated by the model.

CONCLUSIONS

There is a misalignment in the use of cardiac catheterization in patients with non-ST-segment elevation acute coronary syndromes relative to their predicted probability of severe CAD. The use of catheterization appears to target patients who would derive less benefit from revascularization. Further quality improvement efforts should promote appropriate use of cardiac catheterization procedures among patients with the greatest potential benefit.

Pathophysiology of coronary artery disease: the case for multiparametric imaging

Interventions to treat coronary artery disease are available but they must be targeted at the correct individuals (and indeed lesions), in order to gain maximal benefit with the minimal adverse effects. Coronary contrast angiography is not able to provide all the information required for the assessment of the effects of artery disease. Other imaging modalities are of growing importance as they can reduce radiation exposure and invasiveness of screening, as well as providing important extra information. The ideal 'multiparametric' imaging technique would assess anatomy, viability and lesion activity in a single quick scan. Currently, MRI is the technology closest to achieving this ideal, although the existing technology still has some limitations. This review discusses the currently available techniques for the imaging of coronary anatomy and of myocardial viability, and considers their benefits and limitations. We also discuss the developing field of imaging molecularly targeted to active coronary lesions. Finally we provide a 5-year view of the current and likely future optimal imaging strategies.

[A guide to the critical reflection of health services research studies]

Proponents of evidence-based medicine have developed a framework for the critical appraisal of clinical studies. Though this framework is generally accepted, a universal standard for health services research is not yet available. While clinical research evaluates the efficacy and effectiveness of medical interventions, the remit of health services research is to investigate the actual delivery of care in a given health care system. Here, we propose six criteria for the critical appraisal of work published in the field of health services research: the research question, the validity of the study design, the indicators used, the data source, the audience being addressed and the interests behind a study should all be considered when discussing health services research studies. Ideally, health services research should be an integral part of research efforts including basic as well as clinical research.

The elder patient with suspected acute coronary syndromes in the emergency department

OBJECTIVES

To describe the evaluation and outcomes of elder patients with suspected acute coronary syndromes (ACS) presenting to the emergency department (ED).

METHODS

This was a post hoc analysis of the Internet Tracking Registry for Acute Coronary Syndromes (i*trACS) registry, which had 17,713 ED visits for suspected ACS. First visits from the United States with nonmissing patient demographics, 12-lead electrocardiogram results, and clinical history were included in the analysis. Those who used cocaine or amphetamines or left the ED against medical advice were excluded. Elder was defined as age 75 years or older. ACS was defined by 30-day revascularization, Diagnosis-related Group codes, or death within 30 days with positive cardiac biomarkers at index hospitalization. Multivariable logistic regression analyses were performed to determine the association between being elder and 1) 30-day all-cause mortality, 2) ACS, 3) diagnostic tests ordered, and 4) disposition. Multivariable logistic regression was also performed to determine which clinical variables were associated with ACS in elder and nonelder patients.

RESULTS

A total of 10,126 patients with suspected ACS presenting to the ED were analyzed. For patients presenting to the ED, being elder was independently associated with ACS and all-cause 30-day mortality, with adjusted odds ratios of 1.8 (95% confidence interval [CI] = 1.5 to 2.2) and 2.6 (95% CI = 1.6 to 4.3), respectively. Elder patients were more likely to be admitted to the hospital (adjusted odds ratio, 2.2; 95% CI = 1.8 to 2.6), but there were no differences in the rates of cardiac catheterization and noninvasive stress cardiac imaging. Different clinical variables were associated with ACS in elder and nonelder patients. Chest pain as chief complaint, typical chest pain, and previous history of coronary artery disease were significantly associated with ACS in nonelder patients but were not associated with ACS in elder patients. Male gender and left arm pain were associated with ACS in both elder and nonelder patients.

CONCLUSIONS

Elder patients who present to the ED with suspected ACS represent a population at high risk for ACS and 30-day mortality. Elders are more likely to be admitted to the hospital, but despite an increased risk for adverse events, they have similar odds of receiving a diagnostic test, such as stress cardiac imaging or cardiac catheterization, compared with nonelder patients. Different clinical variables are associated with ACS, and clinical prediction rules utilizing presenting symptoms should consider the effect modification of age.

Heart failure with preserved left ventricular systolic function among patients with non-ST-segment elevation acute coronary syndromes

Previous studies of non-ST-segment elevation acute coronary syndromes (NSTE ACSs) complicated by heart failure (HF) have focused primarily on patients with left ventricular systolic dysfunction defined by an ejection fraction (EF) <40%. Little is known about HF with preserved systolic function (EF > or =40%) in the NSTE ACS population. We identified high-risk patients with NSTE ACS (ischemic electrocardiographic changes and/or positive cardiac markers) from the CRUSADE quality improvement initiative who had an EF recorded and who had information on HF status. Management and outcomes were analyzed and compared based on the presence or absence of HF and whether left ventricular EF was > or =40%. Of 94,558 patients with NSTE ACS, 21,561 (22.8%) presented with signs of HF, and most had HF with preserved systolic function (n = 11,860, 55%). Mortality rates were 10.7% for HF/systolic dysfunction, 5.8% for HF/preserved systolic function, 5.7% for no HF/systolic dysfunction, and 1.5% for no HF/preserved systolic function. Use of guideline-recommended medical therapies and interventions was frequently significantly lower in those with HF regardless of EF compared with those without HF, except for use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. In conclusion, NSTE ACS complicated by HF with preserved systolic function is common and associated with a 2.3-fold higher mortality compared with NSTE ACS without HF or systolic dysfunction. Guideline-recommended therapies and interventions are under-utilized in patients with NSTE ACS and HF, with and without preserved systolic function, compared with those without HF.

Role of non-invasive imaging in the management of coronary artery disease: an assessment of likely change over the next 10 years. A report from the British Cardiovascular Society Working Group

Coronary angiography has been the gold standard for determining the severity, extent and prognosis of coronary atheromatous disease for the past 15-20 years. However, established non-invasive testing (such as myocardial perfusion scintigraphy and stress echocardiography) and newer imaging modalities (multi-detector x ray computed tomography and cardiovascular magnetic resonance) now need to be considered increasingly as a challenge to coronary angiography in contemporary practice. An important consideration is the degree to which appropriate use of such techniques impacts on the need for coronary angiography over the next 10-15 years. This review aims to determine the role of the various investigation techniques in the management of coronary artery disease and their resource implications, and should help determine future service provision, accepting that we are in a period of significant technological change.

Trajectories of recovery of quality of life in women after an acute cardiac event

OBJECTIVES

Female cardiac patients' health-related quality of life (HRQoL) during the first year after an acute cardiac event was compared with age-weighted Australian population norms. The impact of age, event type and cardiac rehabilitation (CR) programme attendance on recovery was assessed.

METHODS

The short form 36-item health survey (SF-36) was administered to 229 women aged from 36 to 84 years consecutively admitted to 4 hospitals after acute myocardial infarction (AMI) or to undergo coronary artery bypass graft surgery (CABGS). Data were collected at 4 time points over 12 months. SF-36 subscale scores were compared with age-weighted norms for Australian women. Mplus was used to analyse growth trajectories for SF-36 subscales.

RESULTS

Patients had impaired HRQoL at baseline (except in general health), with progressive improvement over time. Recovery to normative levels was fastest in the areas of bodily pain and mental health (by 2 months) and slowest in the area of physical functioning, and physical and emotional role limitations (by 12 months). By 4 months, general health scores had surpassed population norms. For all scales, most improvement occurred in the first 2 months, with little subsequent improvement. CABGS patients showed significantly more improvement than AMI patients in several areas, partly due to the poorer functioning of CABGS patients at baseline. Rate of improvement was not influenced by patients' age or frequency of CR attendance.

CONCLUSIONS

Impairment of HRQoL in female cardiac patients is most pronounced at the time of the event, with most recovery occurring during early convalescence and full recovery in all domains by 12 months post-event.

Analysis of observational studies in the presence of treatment selection bias: effects of invasive cardiac management on AMI survival using propensity score and instrumental variable methods

CONTEXT

Comparisons of outcomes between patients treated and untreated in observational studies may be biased due to differences in patient prognosis between groups, often because of unobserved treatment selection biases.

OBJECTIVE

To compare 4 analytic methods for removing the effects of selection bias in observational studies: multivariable model risk adjustment, propensity score risk adjustment, propensity-based matching, and instrumental variable analysis.

DESIGN, SETTING, AND PATIENTS

A national cohort of 122,124 patients who were elderly (aged 65-84 years), receiving Medicare, and hospitalized with acute myocardial infarction (AMI) in 1994-1995, and who were eligible for cardiac catheterization. Baseline chart reviews were taken from the Cooperative Cardiovascular Project and linked to Medicare health administrative data to provide a rich set of prognostic variables. Patients were followed up for 7 years through December 31, 2001, to assess the association between long-term survival and cardiac catheterization within 30 days of hospital admission.

MAIN OUTCOME MEASURE

Risk-adjusted relative mortality rate using each of the analytic methods.

RESULTS

Patients who received cardiac catheterization (n = 73 238) were younger and had lower AMI severity than those who did not. After adjustment for prognostic factors by using standard statistical risk-adjustment methods, cardiac catheterization was associated with a 50% relative decrease in mortality (for multivariable model risk adjustment: adjusted relative risk [RR], 0.51; 95% confidence interval [CI], 0.50-0.52; for propensity score risk adjustment: adjusted RR, 0.54; 95% CI, 0.53-0.55; and for propensity-based matching: adjusted RR, 0.54; 95% CI, 0.52-0.56). Using regional catheterization rate as an instrument, instrumental variable analysis showed a 16% relative decrease in mortality (adjusted RR, 0.84; 95% CI, 0.79-0.90). The survival benefits of routine invasive care from randomized clinical trials are between 8% and 21%.

CONCLUSIONS

Estimates of the observational association of cardiac catheterization with long-term AMI mortality are highly sensitive to analytic method. All standard risk-adjustment methods have the same limitations regarding removal of unmeasured treatment selection biases. Compared with standard modeling, instrumental variable analysis may produce less biased estimates of treatment effects, but is more suited to answering policy questions than specific clinical questions.

A comparison of regression trees, logistic regression, generalized additive models, and multivariate adaptive regression splines for predicting AMI mortality

Clinicians and health service researchers are frequently interested in predicting patient-specific probabilities of adverse events (e.g. death, disease recurrence, post-operative complications, hospital readmission). There is an increasing interest in the use of classification and regression trees (CART) for predicting outcomes in clinical studies. We compared the predictive accuracy of logistic regression with that of regression trees for predicting mortality after hospitalization with an acute myocardial infarction (AMI). We also examined the predictive ability of two other types of data-driven models: generalized additive models (GAMs) and multivariate adaptive regression splines (MARS). We used data on 9484 patients admitted to hospital with an AMI in Ontario. We used repeated split-sample validation: the data were randomly divided into derivation and validation samples. Predictive models were estimated using the derivation sample and the predictive accuracy of the resultant model was assessed using the area under the receiver operating characteristic (ROC) curve in the validation sample. This process was repeated 1000 times-the initial data set was randomly divided into derivation and validation samples 1000 times, and the predictive accuracy of each method was assessed each time. The mean ROC curve area for the regression tree models in the 1000 derivation samples was 0.762, while the mean ROC curve area of a simple logistic regression model was 0.845. The mean ROC curve areas for the other methods ranged from a low of 0.831 to a high of 0.851. Our study shows that regression trees do not perform as well as logistic regression for predicting mortality following AMI. However, the logistic regression model had performance comparable to that of more flexible, data-driven models such as GAMs and MARS.

Impact of on-site cardiac catheterization on resource utilization and fatal and non-fatal outcomes after acute myocardial infarction

Background

Patterns of care for acute myocardial infarction (AMI) strongly depend on the availability of on-site cardiac catheterization facilities. Although the management found at hospitals without on-site catheterization does not lead to increased mortality, little it known about its impact on resource utilization and non-fatal outcomes.

Methods

We identified all patients (n = 35,289) admitted with a first AMI in the province of Quebec between January 1, 1996 and March 31, 1999 using population-based administrative databases. Medical resource utilization and non-fatal and fatal outcomes were compared among patients admitted to hospitals with and without on-site cardiac catheterization facilities.

Results

Cardiac catheterization and PCI were more frequently performed among patients admitted to hospitals with catheterization facilities. However, non-invasive procedures were not used more frequently at hospitals without catheterization facilities. To the contrary, echocardiography [odds ratio (OR), 2.04; 95% confidence interval (CI), 1.93–2.16] and multi-gated acquisition imaging (OR, 1.24; 95% CI, 1.17–1.32) were used more frequently at hospitals with catheterization, and exercise treadmill testing (OR, 1.02; 95% CI, 0.91–1.15) and Sestamibi/Thallium imaging (OR, 0.93; 95% CI, 0.88–0.98) were used similarly at hospitals with and without catheterization. Use of anti-ischemic medications and frequency of emergency room and physician visits, were similar at both types of institutions. Readmission rates for AMI-related cardiac complications and mortality were also similar [adjusted hazard ratio, recurrent AMI: 1.02, 95% CI, 0.89–1.16; congestive heart failure: 1.02; 95% CI, 0.90–1.15; unstable angina: 0.93; 95% CI, 0.85–1.02; mortality: 0.99; 95% CI, 0.93–1.05)].

Conclusion

Although on-site availability of cardiac catheterization facilities is associated with greater use of invasive cardiac procedures, non-availability of catheterization did not translate into a higher use of non-invasive tests or have an impact on the fatal and non-fatal outcomes available for study in our administrative database.

Clinical characteristics, process of care, and outcomes of Hispanic patients presenting with non-ST-segment elevation acute coronary syndromes: results from Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA Guidelines (CRUSADE)

BACKGROUND

Data regarding the management of non-ST-segment elevation acute coronary syndromes (NSTE ACS) in Hispanic patients, the largest and fastest-growing minority in the United States, are scarce.

METHODS

We sought to describe the clinical characteristics, process of care, and outcomes of Hispanics presenting with NSTE ACS at US hospitals. We compared baseline characteristics, resource use, and inhospital mortality among 3936 Hispanics and 90280 non-Hispanic whites with NSTE ACS from the CRUSADE Quality Improvement Initiative.

RESULTS

The regional distribution of Hispanics in CRUSADE paralleled that in the US Census. Hispanics were younger (65 vs 70 years, P < .0001) and had less hyperlipidemia (45.4% vs 49.0%, P < .0001) but were more likely to be hypertensive (72.2% vs 67.9%, P < .0001) and diabetic (46.5% vs 30.9%, P < .0001). Hispanics were also more likely to be uninsured (12.5% vs 5.1%, P < .001). During hospitalization, Hispanics were more often managed conservatively, undergoing stress tests more frequently (13.0% vs 10.1%, P < .0001), with less use of cardiac catheterization within 48 hours (48.7% vs 55.5%, P < .0001) or percutaneous coronary intervention (39.6% vs 46.4%, P < .0001) at any time. Hispanics received similar discharge treatments but were less frequently referred for cardiac rehabilitation (38.5% vs 49.2%, P < .0001). Adjusted inhospital mortality was similar in both groups (odds ratio 0.87, 95% CI 0.72-1.05).

CONCLUSIONS

Although hispanics have a different risk factor profile and are treated less aggressively during hospitalization when they present with NSTE ACS, these treatment differences do not appear to affect inhospital outcomes. Further research is warranted to explore the long-term consequences of these findings.

Selection bias of elderly patients with chronic angina referred for catheterization

BACKGROUND

Registry patients are generally older and more sick than patients enrolled in trials questioning the generalizability of trial results. We assessed whether such a selection bias also exists in elderly patients with chronic angina referred for catheterization.

METHODS AND RESULTS

All 119 patients age>or=75 years with Trial of Invasive versus Medical Therapy in the Elderly (TIME) inclusion but no major exclusion criteria referred for catheterization during the TIME trial inclusion period in four TIME centers were registered and followed-up for one year. Registry patients differed from the 188 trial patients in the same hospitals in that they were younger, somewhat more frequently male, with less antianginal drugs and studied more often after acute chest pain at rest but with more comorbidities than study patients. Left ventricular ejection fraction and vessel disease were similar. One year mortality was 11.4% in registry and 9.6% in invasive TIME patients but differences disappeared after adjustment for baseline differences. Symptomatic status after one year was similar too.

CONCLUSIONS

In elderly patients with chronic angina, a bias in the selection for invasive management exists which seems different from that reported in younger patient settings. After adjustment for these selection factors, however, one-year outcome was remarkably similar in registry and trial patients.

Changes in Health Related Quality of Life 3 months after an acute coronary syndrome

Background

The aim of the study was to identify the changes in Health Related Quality of Life (HRQL) 3 months after discharge from hospital, in patients who have had an acute coronary episode, and to determine the clinical and sociodemographic variables that explain those changes.

Methods

HRQL was assessed in 132 patients while they were admitted to the hospital and at 3 months after discharge, using the SF-36 health questionnaire. To identify the variables associated with the change, multiple linear regression models were constructed for two summary dimensions of the SF-36 (PCS and MCS) taking the change in the score of the dimension as dependent variable.

Results

There were no significant differences between the patients who completed the monitoring (n = 76) and those who were dropped out. After three months, a significant decrease was observed in the dimensions of physical functioning, general health, vitality, and Physical Summary Component (PCS). The variables revascularisation, age, and the interaction between previous history of coronary heart disease (CHD) and the presence of one or more risk factors explained 16.6% of the decrease in the PCS. The decrease in the PCS was 6.4 points less in the patients who had undergone revascularisation, 0.2 points less for each year of age, and 4.7 points less in the patients who had antecedents of the illness as well as one or more risk factors.

Conclusion

The dimensions most affected at three months after an acute coronary episode were those related to the physical component. Undergoing revascularisation improved the PCS in patients, but in the younger patients and those without personal antecedents or risk factors, the PCS was affected more, perhaps due to greater expectations for recovery in these patients.

Long-term outcomes of regional variations in intensity of invasive vs medical management of Medicare Patients with acute myocardial infarction

CONTEXT

The health and policy implications of the marked regional variations in intensity of invasive compared with medical management of patients with acute myocardial infarction (AMI) are unknown.

OBJECTIVES

To evaluate patient clinical characteristics associated with receiving more intensive treatment; and to assess whether AMI patients residing in regions with more intensive invasive treatment and management strategies have better long-term survival than those residing in regions with more intensive medical management strategies.

DESIGN, SETTING, AND PATIENTS

National cohort study of 158,831 elderly Medicare patients hospitalized with first episode of confirmed AMI in 1994-1995, followed up for 7 years (mean, 3.6 years), according to the intensity of invasive management (performance of cardiac catheterization within 30 days) and medical management (prescription of beta-blockers to appropriate patients at discharge) in their region of residence. Baseline chart reviews were drawn from the Cooperative Cardiovascular Project and linked to Medicare health administrative data.

MAIN OUTCOME MEASURE

Long-term survival over 7 years of follow-up.

RESULTS

Patient baseline AMI severity was similar across regions. In all regions, younger and healthier patients were more likely than older high-risk patients to receive invasive treatment and medical therapy. Regions with more invasive treatment practice styles had more cardiac catheterization laboratory capacity; patients in these regions were more likely to receive interventional treatment, regardless of age, clinical indication, or risk profile. The absolute unadjusted difference in 7-year survival between regions providing the highest rates of both invasive and medical management strategies and those providing the lowest rates of both was 6.2%. For both ST- and non-ST-segment elevation AMI patients, survival improved with regional intensity of both invasive and medical management. In areas with higher rates of medical management, there appeared to be little or no improvement in survival associated with increased invasive treatment.

CONCLUSIONS

In elderly Medicare patients with AMI, more intensive medical treatment provides population survival benefits. However, routine use of more costly and invasive treatment strategies may not be associated with an overall population benefit beyond that seen with excellent medical management. Efforts should focus on directing invasive clinical resources to patients with the greatest expected benefit.

Invasive versus noninvasive management of ST-elevation acute myocardial infarction: a review of clinical trials and observational studies

BACKGROUND

Despite decades of research, it is still unclear whether patients with uncomplicated ST-segment elevation acute myocardial infarction (AMI) should be managed with an invasive or a noninvasive approach after successful thrombolysis.

METHODS

We reviewed randomized trials in which patients were randomized to a strategy of routine cardiac catheterization after thrombolysis (invasive) or a strategy whereby patients received cardiac catheterization only if they demonstrated reversible ischemia by noninvasive testing (noninvasive). We also reviewed observational studies that compared outcomes for patients who were admitted to hospitals with and without availability of cardiac catheterization facilities or in different geographic regions.

RESULTS

Evidence to date suggests that invasive approach does not result in mortality or reinfarction benefits for patients with uncomplicated ST-segment elevation AMI. However, all except one of the trials performed are dated in view of recent treatment advances, and long-term outcomes for the recent trial have not been published. Several observational studies suggest that the invasive approach may improve "softer" outcomes such as quality of life and functional status.

CONCLUSION

In conclusion, there is currently no evidence to support widespread use of the invasive approach among patients with uncomplicated ST-segment elevation AMI. However, trials with long-term follow-up should be repeated in the current clinical context and should include both hard and softer outcome measures.

Angiography and revascularization in patients with heart failure following fibrinolytic therapy for ST-elevation acute myocardial infarction

We evaluated the use of coronary angiography and clinical outcomes among patients who had heart failure and were enrolled in the Intravenous Novel Plasminogen Activator (NPA) for the Treatment of Infarcting Myocardium Early study, a large international trial of fibrinolytic therapy in ST-elevation myocardial infarction.

Hospital therapy traditions influence long-term survival in patients with acute myocardial infarction

BACKGROUND

Differences in therapy and outcome among hospitals have been reported, but these studies have seldom used adjustment for differences in patient characteristics. The objective was to investigate the differences in treatment of acute myocardial infarction (AMI) among different hospitals within 1 country and the possible causes and outcomes of these differences.

METHODS

Prospective cohort study using data from the Register of Information and Knowledge about Swedish Heart Intensive care Admissions (RIKS-HIA) on 32,954 consecutive primary admissions of patients with AMI admitted to the intensive coronary care units of 67 Swedish hospitals in 1999-2000. An activity index was calculated for each hospital based on the hospital's ranking regarding proportion of performed examination or given therapy among the AMI patients.

RESULTS

After adjustment for 24 background characteristics, there were few significant deviations among hospitals in the proportion treated with acute reperfusion, antiplatelets, beta-blockers, or angiotensin-converting enzyme (ACE) inhibitors. However, 3- to 10-fold differences existed among hospitals in the proportion of patients treated with intravenous beta-blockers, intravenous nitroglycerin, intravenous or subcutaneous anticoagulants, and lipid-lowering medication, and even larger discrepancies in echocardiography and revascularization within 14 days. There was a strong (r = 0.69, P < .001) correlation between hospital activity index between the years and a correlation between the hospital's activity index and 1-year mortality (r = -0.30, P = .014). There was no correlation between hospital size and activity index.

CONCLUSIONS

Even after adjustment for differences in patient characteristics, there are differences between the hospital treatment cultures for patients with AMI that persists over time. Concerning everywhere-available treatment options, the treatment activity is independent of the size of the center. A more active treatment tradition is associated with a lower short- and long-term mortality in AMI patients.

Non-clinical factors influencing the selection of patients with acute coronary syndromes for angiography

OBJECTIVE

To analyse clinical and non-clinical factors determining the selection for coronary angiography in patients with acute coronary syndromes (ACS).

DESIGN

Single centre, prospective cohort study.

PARTICIPANTS

Eighty consecutive patients admitted with a diagnosis of ACS during the period 21 May 2001 to 4 July 2001.

SETTING

Coronary care unit of a tertiary referral centre, the Manchester Royal Infirmary.

DATA COLLECTION

Information concerning baseline patient characteristics, clinical presentation, and the selection for angiography was collected from the patient notes.

DATA COLLECTION

Windows SPSS version 9.0 using cross tabulations with chi(2) estimation and binomial logistic regression analysis.

MAIN OUTCOME MEASURE

Selection for angiography in ACS.

RESULTS

Cross tabulations with chi(2) analysis and logistic regression analysis identified significant non-clinical factors predicting the use of angiography. Although clinical factors such as recurrent ischaemia (odds ratio 5.11) influenced the decision to undergo coronary angiography, non-clinical factors such as young age (odds ratio 6.88 for <65 years old), gender (odds ratio 3.81 for males), admission on a weekday (odds ratio 0.2488 for admission on the weekend), and consultant in charge (odds ratio 0.111 for consultant "2") independently predicted the use of angiography in ACS.

CONCLUSION

The selection of patients for angiography in ACS is not based purely on clinical criteria. Awareness of the apparent sources of bias among clinical decision makers may improve management of these patients.

Standardized approach for developing probabilistic exposure factor distributions

The effectiveness of a probabilistic risk assessment (PRA) depends on the quality and relevance of the output from exposure and risk models, which, in turn, depends on the critical inputs to the assessment. These critical inputs are often in the form of probabilistic exposure factor distributions that are derived for the given risk scenario. Deriving probabilistic distributions for model inputs can be time consuming and subjective. The absence of a standard approach for developing these distributions can result in PRAs that are inconsistent and difficult to review by regulatory agencies. We present an approach that reduces subjectivity in the distribution development process without limiting the flexibility needed to prepare relevant PRAs. The approach requires two steps. First, we analyze data pooled at a population scale to (i) identify the most robust demographic descriptors within the population for a given exposure factor, (ii) partition the data into subsets based on these variables, and (iii) construct archetypal distributions for each subpopulation. Second, we sample from these archetypal distributions according to site- or scenario-specific conditions to simulate exposure factor values and use these values to construct the scenario-specific input distribution. The archetypal distributions developed through Step 1 provide a consistent basis for developing scenario-specific distributions so risk assessors will not have to repeatedly collect and analyze raw data for each new assessment. We demonstrate the approach for two commonly used exposure factors--body weight (BW) and exposure duration (ED)--using data that are representative of the U.S. population. For these factors we provide a first set of subpopulation-based archetypal distributions and demonstrate methods for using these distributions to construct relevant scenario-specific probabilistic exposure factor distributions.

Classification and regression tree analysis in public health: methodological review and comparison with logistic regression

BACKGROUND

Audience segmentation strategies are of increasing interest to public health professionals who wish to identify easily defined, mutually exclusive population subgroups whose members share similar characteristics that help determine participation in a health-related behavior as a basis for targeted interventions. Classification and regression tree (C&RT) analysis is a nonparametric decision tree methodology that has the ability to efficiently segment populations into meaningful subgroups. However, it is not commonly used in public health.

PURPOSE

This study provides a methodological overview of C&RT analysis for persons unfamiliar with the procedure.

METHODS AND RESULTS

An example of a C&RT analysis is provided and interpretation of results is discussed. Results are validated with those obtained from a logistic regression model that was created to replicate the C&RT findings. Results obtained from the example C&RT analysis are also compared to those obtained from a common approach to logistic regression, the stepwise selection procedure. Issues to consider when deciding whether to use C&RT are discussed, and situations in which C&RT may and may not be beneficial are described.

CONCLUSIONS

C&RT is a promising research tool for the identification of at-risk populations in public health research and outreach.

Global patterns of use of antithrombotic and antiplatelet therapies in patients with acute coronary syndromes: insights from the Global Registry of Acute Coronary Events (GRACE)

BACKGROUND

Many agents are available to treat acute coronary syndromes (ACS), yet limited information is available about their use from a multinational perspective. The objective of this report was to describe patterns of use of antithrombotic and antiplatelet therapies in patients with the spectrum of ACS through the use of data from the Global Registry of Acute Coronary Events (GRACE).

METHODS

Data from 12,665 patients with ACS were analyzed. Baseline characteristics, clinical presentation, and medication use were compared. Regional differences in the administration of antiplatelet and antithrombotic therapies were analyzed. Multivariable logistic regression was implemented to determine independent variables indicating the use of various hospital therapies.

RESULTS

Overall, unfractionated heparin was used in 57% of patients and low-molecular-weight heparin in 47% (P <.0001). More than 90% of patients received aspirin, but approximately 13% were not discharged on aspirin. Overall, 30% of patients received thienopyridines (with percutaneous coronary intervention [PCI] in 79%). Of those who did not receive aspirin, 31% received thienopyridines. Intravenous glycoprotein inhibitors were given to 17% of patients. Among those treated with PCI, only 47% received glycoprotein inhibitors, and 21% of those given glycoprotein inhibitors did not undergo PCI. Significant geographic variation was apparent in the use of unfractionated heparin, low-molecular-weight heparin, thienopyridines, and glycoprotein inhibitors.

CONCLUSIONS

Despite the availability of guidelines, striking geographic and practice variations are apparent in the use of antithrombotic and antiplatelet therapies. There remains significant room for improvement in the use of these therapies in patients with ACS, which should lead to improvement in care and outcomes.

Randomized comparison of percutaneous transluminal coronary angioplasty and medical therapy in stable survivors of acute myocardial infarction with single vessel disease: a study of the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte

BACKGROUND

Percutaneous transluminal coronary angioplasty of the infarct-related artery in stable survivors of acute myocardial infarction is often performed, even in patients without any symptoms or residual ischemia. Despite the lack of randomized studies, it is widely believed that this intervention will improve the clinical outcome of these patients.

METHODS AND RESULTS

Three hundred patients with single vessel disease of the infarct vessel and no or minor angina pectoris in the subacute phase (1 to 6 weeks) after an acute myocardial infarction were randomized to angioplasty (n=149) or medical therapy (n=151). Primary end point was the survival free of reinfarction, (re)intervention, coronary artery bypass surgery, or readmission for severe angina pectoris at 1 year. The event-free survival at 1 year was 82% in the medical group and 90% in the angioplasty group (P=0.06). This difference was mainly driven by the difference in the need for (re)interventions (20 versus 8, P=0.03). At long-term follow-up (mean, 56 months), survival was 89% and 96% (P=0.02). Survival free of reinfarction, (re)intervention, or coronary artery bypass surgery was 66% and 80% in the medically and interventionally treated patients, respectively (P=0.05). The use of nitrates was significantly lower in the angioplasty group, both at 1 year (38% versus 67%, P=0.001) and at long-term follow-up (36% versus 55%, P=0.006).

CONCLUSIONS

Percutaneous revascularization of the infarct-related coronary artery in stable patients with single vessel disease improves clinical outcome at long-term follow-up and reduces the use of nitrates. The results of our study should be reproduced in a confirmatory study with a larger sample size before percutaneous coronary intervention in this low-risk patient subgroup, after myocardial infarction can be recommended as routine treatment in clinical practice.

Gap between guidelines and management of patients with acute coronary syndrome without persistent ST elevation. Finnish prospective follow-up survey

OBJECTIVE

To evaluate how new treatment guidelines of acute coronary syndrome (ACS) without ST elevation have been implemented into clinical practice in Finland.

DESIGN

A prospective survey on 501 consecutive patients (mean age 68 [range 27-96] years) admitted to nine hospitals in Finland with suspected ACS without persistent ST elevation between January and March 2001.

RESULTS

The rate of death was 4.2% in hospital and 9.8% at 6 months. Six-month composite incidence of death, new myocardial infarction, refractory angina or readmission for unstable angina was 25.4%. The majority of patients had beta-blocker and aspirin both in hospital and at 6 months. Low molecular weight heparin was used in 76% of patients. Statins were used in 52% of patients in hospital and in 64% at 6 months. Glycoprotein (GP) IIb/IIIa receptor antagonists were used in 18% of all patients. The overall rate of coronary angiography was 40% in hospital and 54% at 6 months, but there was large interhospital variation. Overall, only 45% of very high-risk patients underwent angiography during initial hospitalization. Very high-risk patients had longer waiting times for angiography than low-risk patients (5.8 vs 4.5 days, p < 0.05).

CONCLUSION

Traditional medication with aspirin and beta-blocker is widely used in ACS, whereas statins, GPIIb/IIIa receptor antagonists and invasive therapy are underused. Well-known risk factors were poor predictors of receiving in-hospital angiography. Implementation of new ESC guidelines into clinical practice needs further education and more resources.

Underuse of evidence-based treatment modalities in diabetic patients with non-ST elevation acute coronary syndrome. A prospective nation wide study on acute coronary syndrome (FINACS)

This study was designed to evaluate how new treatment guidelines of acute coronary syndrome (ACS) without ST elevation have been implemented in clinical practice especially in diabetic patients. A prospective follow-up was performed on 501 consecutive patients with suspected ACS without ST elevation admitted to nine hospitals in Finland between 15 January and 11 March 2001. The study group included 143 (29%) diabetic patients. Their risk profile was more severe than in non-diabetic patients; ST-depression on admission electrocardiography 57 versus 38%; P<0.0001, elevated troponin levels 66 versus 56%; P<0.05. Six months composite incidence of death, new myocardial infarction (MI), refractory angina or readmission for unstable angina was 39% in diabetic patients and 20% in non-diabetic patients (P<0.0001). In spite of this more severe risk profile, glycoprotein (GP) IIb/IIIa receptor antagonists and statins were used with similar frequency in non-diabetic and diabetic patients (15 vs. 19 and 48 vs. 54%, respectively; P=NS for both). In diabetic patients mean delay for in hospital coronary angiography was longer (6.4 vs. 4.2 days, P<0.05) and it was performed less often (32 vs. 45% P<0.05). Our results show that diabetic patients with ACS have higher risk profile and worse outcome than non-diabetic patients. Despite their indisputable benefits in diabetic patients, statins, GP IIb/IIIa receptor antagonists and invasive strategy were underused or often neglected. Further education is needed to change attitudes and to better implement new guidelines into clinical practice.

Regionalization and the underuse of angiography in the Veterans Affairs Health Care System as compared with a fee-for-service system

BACKGROUND

Policies to concentrate or regionalize invasive procedures at high-volume medical centers are under active consideration. Such policies could improve outcomes among those who undergo procedures while increasing their underuse among those who never reach such centers. We compared the underuse of needed angiography after acute myocardial infarction in a traditional Medicare fee-for-service system with underuse in the regionalized Department of Veterans Affairs (VA) health care system.

METHODS

We studied 1665 veterans from 81 VA hospitals and 19,305 Medicare patients from 1530 non-VA hospitals, all of whom were elderly men. We compared adjusted angiography use and one-year mortality among patients for whom angiography was rated as clinically needed. We compared underuse in models before and after controlling for the on-site availability of cardiac procedures.

RESULTS

After adjustment for the need for angiography, underuse was present in both groups, but VA patients remained significantly less likely than Medicare patients to undergo angiography (43.9 percent vs. 51.0 percent; odds ratio, 0.75; 95 percent confidence interval, 0.57 to 0.96). After also controlling for on-site availability of cardiac procedures at the admitting hospital, we found no significant difference in the underuse of angiography among VA patients as compared with Medicare patients (odds ratio, 1.02; 95 percent confidence interval, 0.82 to 1.26) or in one-year mortality (odds ratio, 1.08; 95 percent confidence interval, 0.89 to 1.28).

CONCLUSIONS

There is underuse of needed angiography after acute myocardial infarction in both the VA and Medicare systems, but the rate of underuse is significantly higher in the VA. These differences appear to be associated with limited on-site availability of cardiac procedures in the regionalized VA health care system. Further work should focus on how regionalization policies could be improved with effective referral and triage processes.

Process of care and outcome after acute myocardial infarction for patients with mental illness in the VA health care system: are there disparities?

OBJECTIVE

To compare process of care and outcome after acute myocardial infarction, for patients with and without mental illness, cared for in the Veterans Health Administration (VA) health care system.

DATA SOURCES/SETTING

Primary clinical data from 81 VA hospitals.

STUDY DESIGN

This was a retrospective cohort study of 4,340 veterans discharged with clinically confirmed acute myocardial infarction. Of these, 859 (19.8 percent) met the definition of mental illness. Measures were age-adjusted in-hospital and 90-day cardiac procedure use; age-adjusted relative risks (RE) of use of thrombolytic therapy, beta-blockers, angiotensin converting enzyme (ACE) inhibitors, or aspirin at discharge; risk-adjusted 30-day and one-year mortality.

RESULTS

Patients with mental illness were marginally less likely than those without mental illness to undergo in-hospital angiography (age-adjusted RR 0.90 [95 percent confidence interval: 0.83, 0.98]), but there was no significant difference in the age-adjusted RR of coronary artery bypass graft surgery in the 90 days after admission (0.85 [0.69, 1.05]), or in the receipt of medications of known benefit. For example, ideal candidates with and without mental illness were equally likely to receive beta-blockers at the time of discharge (age-adjusted RR 0.92 [0.82, 1.02]). The risk-adjusted odds ratio (OR) for death in patients with mental illness versus those without mental illness within 30 days was 1.00 (0.75, 1.32), and for death within one year was 1.25 (1.00, 1.53).

CONCLUSIONS

Veterans Health Administration patients with mental illness were marginally less likely than those without mental illness to receive diagnostic angiography, and no less likely to receive revascularization or medications of known benefit after acute myocardial infarction. Mortality at one year may have been higher, although this finding did not reach statistical significance. These findings are consistent with other studies showing reduced health care disparities in the VA for other vulnerable groups, and suggest that an integrated health care system with few financial barriers to health care access may attenuate some health care disparities. Further work should address how health care organizational features might narrow disparities in health care for vulnerable groups.

Population need for coronary revascularisation: are national targets for England credible?

OBJECTIVE

To estimate the need for coronary revascularisation, by using an incidence of indications approach, among 45-84 year olds with stable angina, unstable angina, and acute myocardial infarction.

DESIGN

Modelling exercise. Six key steps along the pathway of care from initial diagnosis in primary or secondary care to revascularisation were defined and the frequency of indications estimated using routine data from hospital admissions and data from studies in the general population, and primary and secondary care.

SETTING AND PATIENTS

Mid-1998 population of England.

INTERVENTION

Coronary revascularisation.

MAIN OUTCOME MEASURE

Ability to benefit (need), defined by randomised trials, expert panel ratings from the ACRE (appropriateness of coronary revascularisation) study, or by informal consensus.

RESULTS

The need for coronary revascularisation was estimated to be 92 000 procedures, equivalent to a rate of 1861 per million population. Overall, the model of need exceeded current provision by 3.3:1, although among people aged 75 years and over the ratio was 7.7:1. A plausible upper estimate of need--obtained by assuming that 90% of patients with stable angina were referred from primary care and that angiography would be performed in 65% of patients with acute myocardial infarction and 75% of patients with unstable angina--was 2626 per million population.

CONCLUSIONS

The national target of 1500 revascularisation procedures per million population is credibly related to population need, although upper estimates of need are considerably higher. Better understanding is required of the benefits of referring patients with specific indications from primary care. The greatest relative increase in provision is required for those aged 75 and older, among whom trial evidence of benefit is scant.

Cascade effects of medical technology

Cascade effect refers to a process that proceeds in stepwise fashion from an initiating event to a seemingly inevitable conclusion. With regard to medical technology, the term refers to a chain of events initiated by an unnecessary test, an unexpected result, or patient or physician anxiety, which results in ill-advised tests or treatments that may cause avoidable adverse effects and/or morbidity. Examples include discovery of endocrine incidentalomas on head and body scans; irrelevant abnormalities on spinal imaging; tampering with random fluctuations in clinical measures; and unwanted aggressive care at the end of life. Common triggers include failing to understand the likelihood of false-positive results; errors in data interpretation; overestimating benefits or underestimating risks; and low tolerance of ambiguity. Excess capacity and perverse financial incentives may contribute to cascade effects as well. Preventing cascade effects may require better education of physicians and patients; research on the natural history of mild diagnostic abnormalities; achieving optimal capacity in health care systems; and awareness that more is not the same as better.