Changes in severity of myocardial infarction and three year survival rates after myocardial infarction in Auckland, 1966-7 and 1981-2

[The transition from acute to chronic ischemic heart disease in Spain, 1980-1994]

BACKGROUND AND OBJECTIVES

The remarkable increase in hospital admissions from heart failure in Spain in the last few years may result paradoxical because it coincides with a decrease in ischemic heart disease mortality, the leading cause of heart failure. A plausible explanation is the increase in ischemic heart disease survival, derived from the recent therapeutic advances, which will translate into an increase in the chronic forms of disease. Thus, an analysis was made of mortality and hospital admission trends due to acute and chronic ischemic heart diseases in the 1980-1994 period in Spain.

METHODS

Population-based study of temporal trends with data of primary diagnosis of acute (CIE-9: 410-411) and chronic (CIE-9: 412-414) ischemic heart disease obtained from the National Vital Statistics and the National Survey of Hospital Morbidity.

RESULTS

The number of deaths due to acute ischemic heart disease has increased by 8.3%, from 18,559 in 1980 to 20,101 in 1994. Deaths due to chronic ischemic heart disease increased by 49.3%, from 4,703 in 1980 to 7,020 in 1994. As a result, chronic forms accounted for 20.2% of all deaths attributable to ischemic heart disease in 1980 and 25.8% in 1994. The age-adjusted acute ischemic heart disease mortality rates decreased by 20.1%, whereas those due to chronic increased by 14.6%. The number and rate of age-adjusted hospital admissions increased remarkably for both acute and chronic ischemic heart disease. Nevertheless, the increase observed with chronic form was higher, from 39.4% of all hospital admissions due to ischemic heart disease in 1980 to 58.4% in 1994. This classification of ischemic heart disease was more notorious among males and younger patients.

CONCLUSION

Currently, we are witnessing a transition from acute to chronic ischemic heart disease. That partly explains the increase in hospital care for heart diseases, particularly ischemic heart disease and heart failure.

Prospective study of patients aged 55 years or less with acute myocardial infarction between 1981 and 1985: outcome 7 years and beyond

OBJECTIVE

To determine the long-term prognosis of patients after a myocardial infarction (MI) at a young age.

DESIGN

Prospective cohort study of patients aged 55 years or less suffering a myocardial infarction.

SETTING

A single coronary care unit admitting patients from the community.

PATIENTS

255 consecutive patients (210 men) aged 55 years or less admitted between 1981 and 1985 after acute MI. Twenty four patients died in hospital or within 3 months of infarction and 11 were lost to further follow up after discharge. Of the remaining patients, 150 (mean (SD) age 48 (5.7) years) able to exercise 3 weeks after infarction and who agreed to undergo coronary angiography were recruited to a study group and seen 18 months, and 3, 5, and 7 years after MI. In addition, a cross sectional analysis of survival was made to a median of 120 months. Seventy 3 month survivors (mean (SD) age 48 (5.8) years) were not recruited to the study group but were traced for late survival through their general practitioners and family health service associations to a median of 130 months.

MAIN OUTCOME MEASURES

Survival in young patients after MI and the survival of 3 month survivors stratified by their ability to exercise and agreement to undergo angiography. The rate of coronary artery surgery (CAGB) and reinfarction during the first 7 years after index MI in patients recruited to the study group.

RESULTS

Sixteen patients (6%) died in hospital and eight (3%) within 3 months of the index infarction. The 7 and 11 year survival rates in the whole cohort of 255 patients were 80% and 66% respectively using life table methods. Survival 7 years after MI, in patients recruited to the study group was better than in those not recruited (93% v 79%, P = 0.001), but thereafter mortality in the study group accelerated and there was no significant difference in survival 11 years after infarction (76% v 67%, P = 0.05). There was a trend towards higher mortality in patients with multivessel disease and severely impaired left ventricular function. During the first 7 years after MI, 38 of 150 patients in the study group underwent CABG and 19 suffered reinfarction, which was fatal in three.

CONCLUSION

The medium-term prognosis of young survivors of MI is good, particularly in patients recruited to the study group. After 7 years there is an increase in mortality and the long-term prognosis is less favourable. This should be taken into account when planning future management and follow up of young patients after MI.

Trends in coded causes of death following definite myocardial infarction and the role of competing risks: the Minnesota Heart Survey (MHS)

We investigated possible differences over time in underlying causes of death among validated definite myocardial infarction cases who were discharged following an index hospitalization in 1970, 1980, and 1985 in the Twin Cities, MN. No changes were observed in underlying causes of death assigned to patients who died prior to discharge in the 3 years. Among in-hospital survivors of definite MI, however, age-adjusted rates of death from non-cardiovascular causes more than doubled between 1970 and 1985 (P < 0.01). More specifically, mortality rates for diabetes mellitus increased significantly from 1970 to 1985 (P < 0.05), while those for neoplasms and diseases of the respiratory system increased non-significantly. Whether these data are the result of artifactual changes in cause of death assignment or real changes in disease severity and comorbidity, these trends in long-term death following acute MI may have had a modest impact on reported community-wide coronary heart disease mortality rates.

Trends in survival of hospitalized myocardial infarction patients between 1970 and 1985. The Minnesota Heart Survey

BACKGROUND

The Minnesota Heart Survey is a population-based study designed to monitor and explain trends in cardiovascular mortality, morbidity, and risk factors. As part of this effort, a 50% sample of patients hospitalized for myocardial infarction (MI) in the seven-county Twin Cities (Minneapolis and St. Paul) metropolitan area was reviewed in 1970, 1980, and 1985. Those with a validated definite MI were followed for 4-year mortality. The purpose was to determine whether the improved survival observed between 1970 and 1980 was extended to the 1980-1985 period.

METHODS AND RESULTS

Crude 28-day mortality in men changed from 18% in 1970 to 12% in 1980 to 13% in 1985; in women it changed from 27% in 1970 to 22% in 1980 to 18% in 1985. After adjustment for severity factors (e.g., age, previous MI, and admission heart rate and systolic blood pressure), 28-day mortality was significantly lower in 1980 than in 1970 in men (RR, 0.66; 95% CI, 0.47, 0.92) and in women (RR, 0.69; 95% CI, 0.46, 1.04), but no change occurred from from 1980 to 1985 (p greater than 0.25). After adjustment for severity indicators, 4-year survival was better in 1980 than in 1970 for men (RR, 0.67; 95% CI, 0.54, 0.83) and for women (RR, 0.72; 95% CI, 0.54, 0.98), but there was no significant change from 1980 to 1985 (p greater than 0.25).

CONCLUSIONS

These results suggest that improvements in survival among hospitalized MI patients contributed to the overall decline in coronary heart disease mortality in the Twin Cities area between 1970 and 1980 but not between 1980 and 1985.

Two-year survival after myocardial infarction

We have studied 773 consecutive cases (706 individuals) with definite myocardial infarction treated in the Coronary Care Unit at Danderyd Hospital in Stockholm during the period 1984-85. Hospital mortality was 12.9% in all patients and 8.9% in patients under 70 years of age. Six hundred and six patients were discharged from the hospital and followed up for 2 years. The 2-year mortality in ischaemic heart disease was 14.4% in all patients and 9.5% in patients under 70 years of age and, including all causes of death, 20.3% and 14.6%, respectively. Our policy for medical treatment included frequent use of beta-adrenergic blocking agents, even in heart failure, and restricted use of antiarrhythmic drugs and digitalis. A short delay of admission may have been beneficial for the result of different kinds of anti-ischaemic intervention. Furthermore, a routinely performed exercise ECG before discharge and after 6 weeks, as part of a structured follow-up, has improved our ability to detect complications at an early stage and to optimize medical treatment.