Trends in severity of hospitalized myocardial infarction: the atherosclerosis risk in communities (ARIC) study, 1987-1994

Association Between Thyroid Dysfunction and Incident Dementia in the Atherosclerosis Risk in Communities Neurocognitive Study

BACKGROUND

Abnormal thyroid hormone levels (high or low) and autoimmunity from autoimmune thyroid disease (AITD) may increase dementia risk.

METHODS

We examined the associations of thyroid dysfunction or possible AITD in 1990 - 1992 with dementia through 2017 in the Atherosclerosis Risk in Communities (ARIC) Neurocognitive Study. Thyroid dysfunction (subclinical and overt hypo- or hyperthyroidism and euthyroidism) was categorized from serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) cut-points and AITD from anti-thyroid peroxidase (anti-TPO) antibody positivity. Dementia was identified primarily based on cognitive test performance, neuropsychological examinations and clinician review of suspected cases. Additional cases of dementia were ascertained through telephone interviews or relevant hospital and death certificate codes. Cox regression with multivariable adjustment was used for analysis.

RESULTS

After exclusions for missing data, 12,481 participants were included in the analysis (mean index exam age 57 ± 5.7 (44% male, 25% black)), and 2,235 incident dementia cases were identified. AITD was not significantly associated with dementia. Subclinical hypothyroidism was associated with a lower risk of dementia (hazard ratio (HR) (95% confidence interval (CI)): 0.74 (0.60 - 0.92)), while overt hyperthyroidism was associated with a higher risk of dementia (HR (95% CI): 1.40 (1.02 - 1.92)) compared to euthyroid participants. Participants with serum FT4 concentrations above the 95th percentile were at an increased risk of dementia compared to those in the middle 90% of FT4 (HR (95% CI): 1.23 (1.02 - 1.48)).

CONCLUSIONS

Subclinical hypothyroidism was associated with reduced risk of dementia, whereas overt hyperthyroidism, particularly very elevated FT4, was associated with increased risk of dementia. The association between subclinical hypothyroidism and reduced risk of dementia cannot be explained, but may have been an artifact due to change. By extrapolation, effective treatment of overt hyperthyroidism may modestly reduce dementia risk in older adults.

Relationship Between Midlife Cardiovascular Health and Late-Life Physical Performance: The ARIC Study

OBJECTIVES

To examine the association between midlife cardiovascular health and physical performance 25 years later.

DESIGN

Cohort study (Atherosclerosis Risk in Communities Study); multinomial logistic and logistic regression adjusted for demographic characteristics and clinical measures.

SETTING

Four U.S. communities: Forsyth County, North Carolina; Washington County, Maryland; Minneapolis, Minnesota; and Jackson, Mississippi.

PARTICIPANTS

Individuals aged 54.2 ± 5.8 at baseline (N = 15,744; 55% female, 27% black).

MEASUREMENTS

Cardiovascular health was measured at baseline using the American Heart Association's Life's Simple 7 (LS7) score (0-14) and LS7 component categories (poor, intermediate, ideal) for each risk factor. The Short Physical Performance Battery (SPPB) was used to quantify physical function as ordinal (0-12) and categorical (low (0-6), fair (7-9), good (10-12) outcomes.

RESULTS

Mean baseline LS7 score was 7.9 ± 2.4; 6,144 (39%) individuals returned 25 years later for the fifth ARIC examination, at which point the SPPB was administered. Of 5,916 individuals who completed the SPPB, 3,288 (50%) had good physical performance. Each 1-unit increase in LS7 score was associated with a 17% higher SPPB score (rate ratio (RR) = 1.17, 95% confidence interval (CI) = 1.15-1.19) and a 29% greater chance of having a late-life SPPB score of 10 or greater compared to SPPB score of less than 10 (RR = 1.29, 95% CI = 1.25-1.34). Ideal baseline glucose (RR = 2.53, 95% CI = 2.24-2.87), smoking (RR = 1.97, 95% CI = 1.81-2.15), blood pressure (RR = 1.70, 95% CI = 1.54-1.88), body mass index (RR = 1.51, 95% CI = 1.37-1.66), and physical activity (RR = 1.31, 95% CI = 1.20-1.43) had the strongest associations with late-life SPPB score, adjusting for other LS7 components.

CONCLUSION

Better cardiovascular health during midlife may lead better physical functioning in older age.

Sex-specific trends in 4-year survival in 37 276 men and women with acute myocardial infarction before the age of 55 years in Sweden, 1987-2006: a register-based cohort study

OBJECTIVE

To examine sex-specific trends in 4-year mortality among young patients with first acute myocardial infarction (AMI), 1987-2006.

DESIGN

Prospective cohort study.

SETTING

Sweden.

PARTICIPANTS

We identified 37 276 cases (19.4% women; age, 25-54 years) from the Swedish Inpatient Register, 1987-2006, who had survived 28 days after an AMI.

OUTCOME MEASURES

4-year mortality from all causes and standard mortality ratio (SMR).

RESULTS

From the first to last 5-year period, the absolute excess risk decreased from 1.38 to 0.50 and 1.53 to 0.59 per 100 person-years among men aged 25-44 and 45-54 years, respectively. Corresponding figures for women were a decrease from 2.26 to 1.17 and from 1.93 to 1.45 per 100 person-years, respectively. Trends for women were non-linear, decreasing to the same extent as those for men until the third period, then increasing. For the last 5-year period, the standardised mortality ratio for young survivors of AMI compared with the general population was 4.34 (95% CI 3.04 to 5.87) and 2.43 (95% CI 2.12 to 2.76) for men aged 25-44 and 45-54 years, respectively, and 13.53 (95% CI 8.36 to 19.93) and 6.42 (95% CI 5.24 to 7.73) for women, respectively. Deaths not associated with cardiovascular causes increased from 21.5% to 44.6% in men and 41.5% to 65.9% in women.

CONCLUSIONS

Young male survivors of AMI have low absolute long-term mortality rates, but these rates remain twofold to fourfold that of the general population. After favourable development until 2001, women now have higher absolute mortality than men and a 6-fold to 14-fold risk of death compared with women in the general population.

Prognostic significance of serial Q/ST-T changes by the Minnesota Code and Novacode in the Atherosclerosis Risk in Communities (ARIC) study

AIMS

To compare the value of serial electrocardiographic (ECG) changes by the two most widely used ECG classification systems-the Minnesota Code (MC) and Novacode (Nova) for the prediction of subsequent coronary heart disease (CHD) and total mortality.

METHODS AND RESULTS

We studied 12-lead ECGs from 12,477 participants (average age 54 years at baseline; 58% women; 76% non-Hispanic white) in the Atherosclerosis Risk in Communities (ARIC) Study, who were free of CHD at baseline in 1987, had both good-quality ECGs at baseline and at first study-scheduled follow-up visit, and had ECG QRS duration <120 ms. A total 2119 participants died (17%), including 280 CHD deaths during an average 17-year follow up. Cox regression models assessed outcome associated with significant serial ECG changes by MC and Nova separately. For CHD death the hazard ratio was 6.8 (95% CI 3.5-13.3) for incident Nova myocardial infarction (MI), and 5.7 (95% CI 2.7-11.9) for MC-MI in a multivariable model adjusted for clinical and demographic characteristics, and ECG left ventricular hypertrophy. The increased risk for total mortality doubled for both Nova and MC serial ECG MI. Major evolving ST-T wave abnormalities alone were associated with a ≥132% increased risk for CHD death and a 50% increased risk for total mortality by either Nova or MC.

CONCLUSION

ECG serial change by both MC and Nova are equally valuable predictors for future fatal cardiac events and total mortality and hence equally useful prognostic indicators in clinical trials and epidemiological studies.

Depression as a predictor of work resumption following myocardial infarction (MI): a review of recent research evidence

BACKGROUND

Depression often coexists with myocardial infarction (MI) and has been found to impede recovery through reduced functioning in key areas of life such as work. In an era of improved survival rates and extended working lives, we review whether depression remains a predictor of poorer work outcomes following MI by systematically reviewing literature from the past 15 years.

METHODS

Articles were identified using medical, health, occupational and social science databases, including PubMed, OVID, Medline, Proquest, CINAHL plus, CCOHS, SCOPUS, Web of Knowledge, and the following pre-determined criteria were applied: (i) collection of depression measures (as distinct from 'psychological distress') and work status at baseline, (ii) examination and statistical analysis of predictors of work outcomes, (iii) inclusion of cohorts with patients exhibiting symptoms consistent with Acute Coronary Syndrome (ACS), (iv) follow-up of work-specific and depression specific outcomes at minimum 6 months, (v) published in English over the past 15 years. Results from included articles were then evaluated for quality and analysed by comparing effect size.

RESULTS

Of the 12 articles meeting criteria, depression significantly predicted reduced likelihood of return to work (RTW) in the majority of studies (n = 7). Further, there was a trend suggesting that increased depression severity was associated with poorer RTW outcomes 6 to 12 months after a cardiac event. Other common significant predictors of RTW were age and patient perceptions of their illness and work performance.

CONCLUSION

Depression is a predictor of work resumption post-MI. As work is a major component of Quality of Life (QOL), this finding has clinical, social, public health and economic implications in the modern era. Targeted depression interventions could facilitate RTW post-MI.

Triggering of transmural infarctions, but not nontransmural infarctions, by ambient fine particles

BACKGROUND

Previous studies have reported increased risk of myocardial infarction (MI) after increases in ambient particulate matter (PM) air pollution concentrations in the hours and days before MI onset.

OBJECTIVES

We hypothesized that acute increases in fine PM with aerodynamic diameter < or = 2.5 microm (PM(2.5)) may be associated with increased risk of MI and that chronic obstructive pulmonary disease (COPD) and diabetes may increase susceptibility to PM(2.5). We also explored whether both transmural and nontransmural infarctions were acutely associated with ambient PM(2.5) concentrations.

METHODS

We studied all hospital admissions from 2004 through 2006 for first acute MI of adult residents of New Jersey who lived within 10 km of a PM(2.5) monitoring site (n = 5,864), as well as ambient measurements of PM(2.5), nitrogen dioxide, sulfur dioxide, carbon monoxide, and ozone.

RESULTS

Using a time-stratified case-crossover design and conditional logistic regression showed that each interquartile-range increase in PM(2.5) concentration (10.8 microg/m3) in the 24 hr before arriving at the emergency department for MI was not associated with MI overall but was associated with an increased relative risk of a transmural infarction. We found no association between the same increase in PM(2.5) and nontransmural infarction. Further, subjects with COPD appeared to be particularly susceptible, but those with diabetes were not.

CONCLUSIONS

This PM-transmural infarction association is consistent with earlier studies of PM and MI. The lack of association with nontransmural infarction suggests that future studies that investigate the triggering of MI by ambient PM(2.5) concentrations should be stratified by infarction type.

Trends in incidence, severity, and outcome of hospitalized myocardial infarction

BACKGROUND

In 2000, the definition of myocardial infarction (MI) changed to rely on troponin rather than creatine kinase (CK) and its MB fraction (CK-MB). The implications of this change on trends in MI incidence and outcome are not defined.

METHODS AND RESULTS

This was a community study of 2816 patients hospitalized with incident MI from 1987 to 2006 in Olmsted County, Minnesota, with prospective measurements of troponin and CK-MB from August 2000 forward. Outcomes were MI incidence, severity, and survival. After troponin was introduced, 278 (25%) of 1127 incident MIs met only troponin-based criteria. When cases meeting only troponin criteria were included, incidence did not change between 1987 and 2006. When restricted to cases defined by CK/CK-MB, the incidence of MI declined by 20%. The incidence of non-ST-segment elevation MI increased markedly by relying on troponin, whereas that of ST-segment elevation MI declined regardless of troponin. The age- and sex-adjusted hazard ratio of death within 30 days for an infarction occurring in 2006 (compared with 1987) was 0.44 (95% confidence interval, 0.30 to 0.64). Among 30-day survivors, survival did not improve, but causes of death shifted from cardiovascular to noncardiovascular (P=0.001). Trends in long-term survival among 30-day survivors were similar regardless of troponin.

CONCLUSIONS

Over the last 2 decades, a substantial change in the epidemiology of MI occurred that was only partially mediated by the introduction of troponin. Non-ST-segment elevation MIs now constitute the majority of MIs. Although the 30-day case fatality improved markedly, long-term survival did not change, and the cause of death shifted from cardiovascular to noncardiovascular.

Relation between myocardial infarct size and ventricular tachyarrhythmia among patients with preserved left ventricular ejection fraction following fibrinolytic therapy for ST-segment elevation myocardial infarction

In the era of early reperfusion therapy for ST-segment elevation myocardial infarction, preserved left ventricular (LV) function is common. Despite preservation of LV ejection fraction (LVEF), there remains a spectrum of risk for adverse cardiovascular events, including ventricular tachycardia (VT) and ventricular fibrillation (VF). Larger infarct size has been independently associated with death, VT/VF, and heart failure in the post-myocardial infarction population. It was hypothesized that infarct size, as estimated by peak serum creatine kinase (CK)-MB concentration, would be associated with the incidence of VT/VF in patients with preserved LV function after ST-segment elevation myocardial infarctions. The Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis In Myocardial Infarction 28 (CLARITY-TIMI 28) study enrolled 3,491 patients with ST-segment elevation myocardial infarctions who underwent fibrinolytic therapy. The association between estimated infarct size (ratio of peak CK-MB to the upper limit of normal), the LVEF (measured using left ventriculography or echocardiography), and the incidence of VT/VF through 30 days was assessed. A total of 1,436 patients underwent assessments of LV function, of whom 1,133 had adequate CK-MB for analysis. The median LVEF in this group was 55% (interquartile range 45% to 65%), and most patients (n = 814 [87.1%]) had LVEF > or =40%. Among patients with LVEF > or =40%, the ratio of peak CK-MB to the upper limit of normal was significantly associated with the incidence of VT/VF through 30 days (2.2%, 3.7%, and 5.5% across tertiles, respectively, p = 0.041 for trend) and the incidence of the composite of cardiovascular death, heart failure, shock, and VT/VF through 30 days (3.7%, 6.0%, 8.5%, respectively, p = 0.018 for trend). In conclusion, in patients with ST-segment elevation myocardial infarction with preserved LV function after reperfusion therapy, larger infarct size, as estimated by peak serum CK-MB concentration, is significantly associated with VT/VF as well as other adverse clinical outcomes.

Declining severity of myocardial infarction from 1987 to 2002: the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Death rates for coronary heart disease have been declining in the United States, but the reasons for this decline are not clear. One factor that could contribute to this decline is a reduction in the severity of acute myocardial infarction (MI). We hypothesized that for those patients hospitalized in the Atherosclerosis Risk in Communities (ARIC) Study with acute incident MI, there was a decline in MI severity from 1987 to 2002.

METHODS AND RESULTS

The community surveillance component of the ARIC Study consisted of tracking residents 35 to 74 years of age with hospitalized MI or fatal coronary heart disease in 4 diverse communities. For incident, hospitalized MI, a probability sample of hospital discharges was validated and an MI classification was assigned according to an algorithm consisting of chest pain, ECG evidence, and cardiac biomarkers. Severity indicators were chosen from abstracted hospital charts validated as a definite or probable MI. With few exceptions, the MI severity indicators suggested a significant decline in the severity of MI during the period of 1987 to 2002. The percent of MI cases with major ECG abnormalities decreased as evidenced by a 1.9%/y (P=0.002) decline in the proportion of those with initial ST-segment elevation, a 3.9%/y (P<0.001) decline in those with subsequent Q-waves, and a 4.5%/y (P<0.001) decline in those with any major Q wave. Maximum creatine kinase and creatine kinase-MB values declined (5.2% and 7.6%; P<0.001, P<0.001 per year, respectively), although in the later years, maximum troponin I values remained stable (1.1%/y decline; P=0.66). The percent with shock declined (5.7%/y; P<0.001), although those with congestive heart failure remained stable. A combined severity score, the Predicting Risk of Death in Cardiac Disease Tool (PREDICT) score, also declined (0.2%/y; P<0.001). Results for blacks paralleled those of the entire group, as did results for women.

CONCLUSIONS

Evidence from ARIC community surveillance suggests that the severity of acute MI has declined among community residents hospitalized for incident MI. This reduction in severity may have contributed, along with other factors, to the decline in death rates for coronary heart disease.

Electrocardiographic findings at presentation, in relation to in-hospital mortality and 30-day outcome of patients with Acute Coronary Syndromes; The GREECS study

BACKGROUND

We sought to evaluate the impact of initial electrocardiographic findings at presentation on in-hospital mortality and 30-day outcome of patients with acute coronary syndromes (ACS).

METHODS

From October 2003 to September 2004, a sample of 6 hospitals located in several urban and rural Greek regions was selected, and almost all survivors 24 h after an admission for ACS were enrolled into the study (2172 patients were included in the study; 76% were men and 24% women). ECG and biochemical indices of myocardial damage were considered in all patients. Electrocardiographic findings at presentation were categorized as ST-elevation (STE), non-STE and non-diagnostic ECG abnormalities.

RESULTS

Of the 2172 patients, 34% had STE, 24% had non-STE and the 32% of them had non-diagnostic ECG abnormalities. After adjusting for age, sex and various other risk factors we observed that patients with STE had 3.3 (95% CI 1.4 to 7.7) higher risk of dying during hospitalization compared to those who had non-diagnostic ECG abnormalities. Furthermore, patients with non-STE had 1.5 (95% CI 0.9 to 2.5) higher risk of having an event (death or re-hospitalization due to CVD) during the first 30-days following discharge as compared to those who had non-diagnostic ECG abnormalities. All patients presented with non-STE ACS had higher 30-day event rates.

CONCLUSION

Patients with STE had higher in-hospital mortality, but lower longer term event rate after ACS in our population, irrespective of age, gender and other characteristics.

Epidemiology of myocardial infarction

Myocardial infarction is a key component of the burden of cardiovascular disease. The assessment of the incidence and case fatality of myocardial infarction are important determinants of the decline in coronary disease mortality. The change in biomarkers used to diagnose myocardial infarction raises several methodologic, clinical, and public health challenges, which are discussed herein.

[Epidemiology of acute coronary syndrome in Europe]

Epidemiological data concerning acute coronary syndromes in Europe are based on national registries, studies by the European Society of Cardiology within the framework of the EuroHeart Survey and on the study of European population sub-groups in large international cohorts. In this article, recently published studies will be reviewed, and the principal developments in different countries as well as the characteristics and particularities of the most recent epidemiological data will be highlighted. In Europe, the presentation of acute coronary syndromes (ACS) has evolved considerably over the last ten years. This evolution is characterized by a reduction in the proportion of acute coronary syndromes with ST-segment elevation (STEMI) and by ageing populations.

Trends in Acute Myocardial Infarction in 4 US States Between 1992 and 2001

Background— Because of the health impact of acute myocardial infarction (AMI), substantial resources have been dedicated to improving AMI care and outcomes. Long-term trends in the clinical characteristics, quality of care, and outcomes for AMI over time from the health system perspective in geographically diverse populations are not well known.

Methods and Results— The present study included 20 550 Medicare patients aged ≥65 years hospitalized in 4 US states (Alabama, Connecticut, Iowa, Wisconsin) with the confirmed primary discharge diagnosis of AMI in 4 periods: 1992–1993 (n=10 292), 1995 (n=5566), 1998–1999 (n=2413), and 2000–2001 (n=2279). With the use of standard quality indicator definitions, treatment of ideal candidates with aspirin and β-blockers within 24 hours after presentation, β-blockers, and angiotensin-converting enzyme inhibitors at discharge was assessed. Multivariable models were constructed to calculate adjusted 1-year mortality. The hospitalized Medicare population with AMI changed substantially during 1992–2001, with increasing age, more comorbidity, and fewer meeting ideal treatment criteria. Although treatment rates increased significantly for all medications, aspirin, β-blockers, and angiotensin-converting enzyme inhibitors were not provided at discharge to 12.6%, 19.7%, and 25.2% of ideal candidates, respectively, in 2000–2001. Crude 1-year mortality increased (27.6%, 28.3%, 30.6%, and 31.0%; P =0.003 for trend, but adjusted mortality declined (compared with 1992–1993, relative risk in 1995=0.94 [95% CI, 0.88 to 1.01]; relative risk in 1998–1999=0.91 [95% CI, 0.85 to 0.98]; relative risk in 2000–2001=0.87 [95% CI, 0.81 to 0.94]).

Conclusions— The quality of care and adjusted 1-year mortality improved significantly for Medicare beneficiaries with AMI during 1992–2001. Nevertheless, fewer were ideal for guideline-based therapy, and absolute mortality remains high, suggesting the need for treatment strategies applicable to a broader range of older patients.

Trends in acute myocardial infarction complicated by cardiogenic shock, 1979-2003, United States

BACKGROUND

Acute myocardial infarction (AMI) complicated by cardiogenic shock is associated with high morbidity and mortality.

METHODS

Using the National Hospital Discharge Survey data from 1979 to 2003, we measured trends in the incidence of AMI complicated by cardiogenic shock, the use of percutaneous transluminal coronary angioplasty (PTCA), and the inhospital death.

RESULTS

Age-adjusted hospitalization rates (per 100,000 populations) in 1979 and 2003, respectively, were 213 and 261 for AMI, and 8.6 and 4.3 for AMI complicated by cardiogenic shock. Among patients with AMI, the proportion with cardiogenic shock was 3.9% (n = 17,000) in 1979 and 1.7% (n = 13,000) in 2003. Patients with acute myocardial infarction with cardiogenic shock, compared with those without cardiogenic shock, were more likely to be women (48% vs 43%, P < .0001), more likely to have anterior wall AMI (33% vs 14%, P < .0001), and had much higher inhospital mortality (43% vs 7%, P < .0001). Over the years, among AMI complicated by cardiogenic shock, PTCA use increased substantially from 0% to 28%. During this period, inhospital death decreased from 84% to 43%. After adjustment for age, sex, location of AMI, health insurance, and survey year, PTCA use was significantly associated with decreased inhospital deaths among patients with AMI with cardiogenic shock.

CONCLUSIONS

Although hospitalization for AMI has increased over the past 25 years, the hospitalization rate of AMI complicated by cardiogenic shock has decreased by 50%. At the same time, PTCA use and hospital survival have increased substantially among cardiogenic shock patients.

Age, clinical presentation, and outcome of acute coronary syndromes in the Euroheart acute coronary syndrome survey

AIMS

Age is one of the most powerful determinants of prognosis in myocardial infarction, but there is comparatively little recent data across the whole spectrum of acute coronary syndromes (ACS). We examined the impact of increasing age on clinical presentation and hospital outcome in a large sample of patients with ACS.

METHODS AND RESULTS

Patients (n = 10 253) from the Euroheart ACS survey in 103 hospitals in 25 countries were investigated. There was a significant inverse association between the age and the likelihood of presenting with ST-elevation. For each decade of life, the odds of presenting with ST-elevation decreased by 0.82 [95% confidence interval (CI) 0.79-0.84]; P < 0.0001. Elderly patients were considerably less often treated by cardiologists, less extensively investigated, and, when presenting with ST-elevation ACS, less likely to be treated with reperfusion. Compared with patients <55 years, the odds ratios of hospital mortality were 1.87 (1.21-2.88) at age 55-64, 3.70 (2.51-5.44) at age 65-74, 6.23 (4.25-9.14) at age 75-84, and 14.5 (9.47-22.1) among patients > or =85 years, with no major differences across different types of admission or discharge diagnoses.

CONCLUSION

Elderly ACS patients were less likely to present with ST-elevation but had substantial in-hospital mortality, yet they were markedly less intensively treated and investigated.

Cardiovascular risk factors and clinical presentation in acute coronary syndromes

OBJECTIVE

To investigate the hypothesis that risk factors may be differently related to severity of acute coronary syndromes (ACS), with ST elevation used as a marker of severe ACS.

DESIGN

Cross sectional study of patients with ACS.

SETTING

103 hospitals in 25 countries in Europe and the Mediterranean basin.

PATIENTS

10,253 patients with a discharge diagnosis of ACS in the Euro heart survey of ACS.

MAIN OUTCOME MEASURES

Presenting with ST elevation ACS.

RESULTS

Patients with ACS who were smokers had an increased risk to present with ST elevation (age adjusted odds ratio (OR) 1.84, 95% confidence interval (CI) 1.67 to 2.02). Hypertension (OR 0.65, 95% CI 0.60 to 0.70) and high body mass index (BMI) (p for trend 0.0005) were associated with less ST elevation ACS. Diabetes mellitus was also associated with less ST elevation, but only among men. Prior disease (infarction, chronic angina, revascularisation) and treatment with aspirin, beta blockers, or statins before admission were also associated with less ST elevation. After adjustment for age, sex, prior disease, and prior medication, smoking was still significantly associated with increased risk of ST elevation (OR 1.53, 95% CI 1.38 to 1.69), whereas hypertension was associated with reduced risk (OR 0.75, 95% CI 0.69 to 0.82). Obesity (BMI > 30 kg/m2 versus < 25 kg/m2) was independently associated with less risk of presenting with ST elevation among women, but not among men.

CONCLUSION

Among patients with ACS, presenting with ST elevation is strongly associated with smoking, whereas hypertension and high BMI (in women) are associated with less ST elevation, independently of prior disease and medication.

Cardioprotection before revascularization in ischemic myocardial injury and the potential role of hemoglobin-based oxygen carriers

Despite the availability of interventional catheterization for patients with acute coronary syndromes, there is an unavoidable delay until the occluded coronary artery(s) can be revascularized, during which time persistent ischemia may lead to irreversible myocardial damage despite subsequently high patency rates. Accordingly, there has been an intense effort to develop early interventions that will preserve the viability of ischemic myocardium before revascularization. A number of novel strategies have been studied, including hemoglobin-based oxygen carriers. These compounds transport oxygen in the plasma to help maintain more normal oxygen delivery to the myocardium supplied by a thrombosed vessel, and they also release oxygen to tissue more efficiently than intraerythrocytic hemoglobin.

Secular trends in cardiovascular disease mortality, incidence, and case fatality rates in adults in the United States

PURPOSE

To assess the effects of changes in cardiovascular disease incidence and case fatality rates on secular trends in mortality in the U.S. population between 1971-1982 and 1982-1992.

METHODS

Using data from the first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study, two cohorts (10,869 subjects in the 1971-1982 cohort and 9774 in the 1982-1992 cohort) of participants aged 35 to 74 years were created. Baseline medical history questionnaires were administered in 1971-1975 and 1982-1984, with follow-up interviews, hospital record reviews, and death certificate searches conducted in 1982-1984, 1986, 1987, and 1992.

RESULTS

Between 1971-1982 and 1982-1992, age-standardized cardiovascular disease mortality declined from 79.1 (95% confidence interval [CI]: 75.2 to 83.0) to 53.0 (95% CI: 49.5 to 56.5) per 10,000 person-years, while cardiovascular disease incidence rates decreased from 293.5 (95% CI: 284.5 to 302.4) to 225.1 (95% CI: 216.6 to 233.5) per 10,000 person-years. The 28-day case fatality rate for cardiovascular disease declined from 15.7% (95% CI: 14.5% to 16.8%) to 11.7% (95% CI: 10.3% to 13.0%). After adjustment for age, sex, and race, rates were 31% lower for cardiovascular disease mortality, 21% lower for incidence, and 28% lower for 28-day case fatality in the 1982-1992 cohort than in the 1971-1982 cohort (each P <0.001).

CONCLUSION

The decrease in cardiovascular disease mortality between 1971-1982 and 1982-1992 was due to declines in both the incidence and case fatality rates in this national sample. These findings suggest that both primary and secondary prevention and treatment contributed to the decline in cardiovascular disease mortality in the United States.

Cardiovascular responses to angiotensin II in atherosclerosis

Atherosclerosis is associated with increased angiotensin II AT1-receptor expression and vascular hyperresponsiveness to angiotensin II. Nevertheless, atherosclerosis is often not accompanied by hypertension. We studied if the hypertensive effect of angiotensin II is more pronounced in atherosclerosis. Rabbits were fed a high-cholesterol diet (n = 10) for 12 weeks, followed by a standard diet for another 6 weeks. Control animals received the standard diet (n = 8) for 18 weeks. After 18 weeks, haemodynamic measurements were performed during a baseline recording and during an intravenous infusion of angiotensin II (0.4 microg kg-1 min-1). Atherosclerosis in the high-cholesterol group was verified by histological and lipidchemical tissue examinations. During angiotensin II infusion, total peripheral resistance (TPR) increased more in the high-cholesterol group than in controls (+81.6 +/- 12.4 vs. +40.6 +/- 9.7 mmHg min L-1, P < 0.05). While cardiac output and stroke volume (SV) decreased more in the high-cholesterol group (P < 0.05), reflex bradycardia was stronger in the control group (P < 0.05), indicating a reduced baroreceptor reflex sensitivity in atherosclerosis. Despite the larger increase in TPR and the reduced baroreceptor reflex sensitivity in the high-cholesterol group, maximum blood pressure response to angiotensin II was similar in both groups. The lack of a greater blood pressure response to angiotensin II in the high-cholesterol group could be the result of the early stages of heart failure. Under resting conditions, heart failure seems to be fully compensated, as baseline haemodynamic parameters were similar in the high-cholesterol group and in controls. However, during angiotensin II infusion, the compensatory mechanisms do not prevent a stronger fall in cardiac output and SV. Therefore, the blood pressure response to angiotensin II is not exaggerated in atherosclerotic animals, as vascular hyperresponsiveness to angiotensin II is opposed by the stronger fall in cardiac output and SV.

Coronary revascularization on balance: Robert L. Frye lecture

The first generation of multicenter randomized controlled trials of coronary artery bypass surgery vs medical treatment in the 1970s found survival advantage only in patients with left main coronary artery disease or with multiple risk factors. Over time, these results have remained reproducible and biologically plausible and continue to be the basis for contemporary guidelines for bypass surgery. Percutaneous coronary intervention (PCI), which became available some 10 years after surgery, was compared with medical treatment in various clinical settings. Patients with stable angina receiving aggressive medical therapy had survival rates comparable to those undergoing PCI in several trials. In the presence of unstable angina, evidence suggests benefit from intervention after stabilization. In the setting of acute myocardial infarction or cardiogenic shock, PCI showed results superior to lytic therapy in centers with large PCI volume. A comparison of the 2 revascularization methods in the 1990s resulted in no overall 7-year survival difference except in patients with treated diabetes in whom bypass surgery prolonged life compared with angioplasty. None of the revascularizations had an effect on the incidence of myocardial infarctions, but importantly, the presence of bypass grafts reduced their fatal impact compared with both medical treatment and PCI. All revascularization trials reported improvement in quality of life, including symptoms, compared with less aggressive therapy. In the pursuit to explain 3 decades of steady decline of cardiovascular mortality in the United States, health economists attempted to model the decline due to availability of intervention by estimates obtained from contemporary randomized prevention and intervention trials. They concluded that, thus far, treatments have made a greater contribution to the decline than has primary prevention. Randomized trials not only contribute to evidence-based clinical practice, but also can reveal underlying biological mechanisms and provide quantitative data to model population trends. Thus, they should be regarded as the basic science of medical therapeutics and population health.