Acute myocardial infarction and acute coronary syndrome: then and now (1950-2005)

Advances in the prevention, diagnosis, and treatment of acute myocardial infarction (AMI) and acute coronary syndrome (ACS) have been remarkable since the mid-20th century. Even the clinical terminology used to describe some of the various components of ACS have undergone change, while the latter term itself represents a fairly recent addition to the medical lexicon. Although there have been dramatic changes in the diagnostic and therapeutic interventions used and impressive declines in morbidity and mortality, the differential diagnosis and complications of AMI and ACS remain as challenging now as they were a half century ago. This article presents in detail the medical understanding of AMI in the mid-20th century and how physicians of that era managed it and its complications, and contrasts this with current evidence-based knowledge and interventions.

Coronary heart disease (CHD)--one or several diseases? Changes in the prevalence and features of CHD

In retrospect, mortality from coronary heart disease (CHD) in the 20th century followed an epidemic pattern: mortality rates increased dramatically from 1920 until about 1960, remained roughly constant for almost a decade, and have been decreasing since the late 1960s. CHD has traditionally been conceived of as a single disease with multifactorial causality. We suggest instead that CHD cases may comprise at least two distinct populations: those associated with hypercholesterolemia, and those associated with insulin resistance. The epidemic of CHD was due primarily to changes in the incidence of the hypercholesterolemia subgroup. We propose that young adults who survived the 1918 influenza pandemic were rendered vulnerable to lipid-associated CHD and coronary thrombosis upon reinfection with influenza later in life. This vulnerability may be due to autoimmune disruption of low-density lipoprotein-receptor interactions. Historical events may affect the health of populations by affecting the susceptibility of populations to chronic diseases such as CHD. The life experiences of individuals are known to influence their susceptibility to infectious diseases; we suggest that life experiences may also influence individual susceptibility to chronic diseases.

[Coronary angioplasty: view through 30 years]

Andreas Gruentzig executed the first successful percutaneous transluminal coronary angioplasty (PTCA) in 1977. Percutaneous coronary interventions (PCI) have considerably changed since this time. The changes have touched the technical equipment for PCI, the pharmacological and mechanical support of PTCA also. The serious revision was in recommendations for PCI too. New catheter technologies have allowed to perform successful PCI in patients with an acute myocardial infarction, with multivessel coronary disease and in many others. PCI became the most often method of a coronary revascularization for ischemic heart disease in the nineties. Percutaneous interventions pass ahead of coronary artery bypass graft operations in many countries of Europe and America. The coronary angioplasty is carried out more than in 2 million patients in the world annually, and 1 million patients is exposed to the PCI annually in the USA. Coronary stenting became most frequently used technology of PCI from the middle of the nineties. The implantation of drug-eluting stents has been the dominating catheter-based method in world clinical practice during last three years. Nevertheless, both these technologies are not deprived of restrictions and disadvantages. The coronary restenosis has become the main limitation for standard (bare-metal) stents, and late thrombosis has become the most terrible complication for the drug-eluting stents. The big success of a method and huge increase of quantity of coronary interventions would be impossible without sequence of openings, innovations and other important events which are surveyed in this review.

Dietary fat, coronary heart disease, and cancer: a historical review

OBJECTIVES

This report describes the historical development of medical theories and research concerning the relationship between dietary fat intake and breast and colorectal cancer and coronary heart disease (CHD).

METHOD

The historical and medical literature on this topic was analyzed with special reference to the Woman's Health Initiative (WHI) studies.

RESULTS

After 1900, changes in clothing fashions and life insurance mortality studies created strong preferences for slimness and emphasized reduced dietary fat intake as the preferred method of weight control. After midcentury, ecological correlations of countries found that national average dietary fat intake was related to national breast cancer and CHD rates. These relationships were not found in longitudinal studies of the same countries or in studies of dietary fat intake of individuals, including the WHI study. Dietary fat intake was found to affect colorectal cancer in some studies of individuals, although not the WHI. The WHI, like other intervention studies of dietary fat reduction, used unrepresentative samples and costly lifestyle change techniques that are not economically feasible in the community.

CONCLUSION

The WHI concurred with many other studies in finding that dietary fat intake is not a significant risk factor for CHD or breast cancer.

The “Americanisation” of migrants: Evidence for the contribution of ethnicity, social deprivation, lifestyle and life-course processes to the mid-20th century Coronary Heart Disease epidemic in the US

We investigated the contribution of the large-scale immigration of White Europeans into the US between 1850 and 1930 to the timing and extent of the epidemic pattern of heart disease between 1900 and 1980. The analyses are based on data collected through the United States Federal Census from 1850 to the present. The hardcopy historical record confirms that census reports themselves and related monographs were concerned from 1850 with excessive mortality from heart disease of immigrants, particularly of Northern European origin and initially at least, their first-generation native-born children. Our analysis of the electronic database indicates a strong relationship between the percentage of US population foreign born and native born of foreign parentage and age adjusted mortality from heart disease. We identified a lag of 50 years giving the maximum linear correlation coefficient for men (r(2) = 0.92), and for women a shorter lag of 38 years and an earlier decline in Coronary Heart Disease (CHD) rates (r(2) = 0.96). Both the rise and fall of the CHD epidemic over an 80-year period correspond closely to the rise and fall of the foreign population in previous years. For the foreign born only, age adjusted negative binomial general estimated equation (GEE) models calculate the relative risk of dying of heart disease per 10% increase in proportion foreign born. There is an independent influence for men until 1930 and for women throughout the period from 1910 onwards. We conclude there is an impact of immigration on the pattern of the epidemic, mediated through a combination of factors, such as accumulated life-course susceptibility, deprived socio-economic conditions upon arrival, and the enthusiastic uptake of behaviours related to the classic risk factors of smoking, high saturated fat and salt diet. Our analysis provides a more contextualised understanding of the scale and timing of the epidemic of CHD in the US.

Profiling risk: the emergence of coronary heart disease epidemiology in the United States (1947-70)

This historical study examines the development of coronary heart disease (CHD) research and its role in the evolution of post-1945 chronic disease epidemiology in the United States. To give the examination greater salience, it compares the pathway represented by CHD epidemiology with that of lung cancer. Historians have paid less attention to the differences between the two, which later merged into what we now call 'risk factor epidemiology'. This study assesses why CHD epidemiology in the post-war period almost uniformly began with cohort studies and primarily stressed clinical variables as putative aetiological factors. It describes how CHD epidemiologists sought to justify the creation of a non-infectious chronic disease epidemiology, a position reinforced by the relative swiftness with which they obtained important results. It also follows the emergence of 'risk factor thinking' within CHD epidemiology. CHD epidemiology critically differed from its lung cancer counterpart in that it identified multiple factors of risk, each producing relatively small effects, rather than a single factor producing a strong and evident outcome. Consequently, it was difficult for CHD epidemiologists to demonstrate causality and to confirm scientifically that reducing risk factors would lower CHD rates. This had significant consequences for primary prevention and public health policy.

Thematic review series: The Pathogenesis of Atherosclerosis. An interpretive history of the cholesterol controversy, part IV: The 1984 Coronary Primary Prevention Trial ends it—almost

As of the early 1980s, despite the wealth of evidence from experimental animal models, the extensive epidemiologic evidence, the powerful genetic evidence, and the strongly suggestive clinical intervention trial results, most clinicians still remained unpersuaded regarding the relevance of the lipid hypothesis. What was needed was a well-designed, large-scale, long-term, double-blind study demonstrating a statistically significant impact of treatment on coronary heart disease events. The National Institutes of Health (NIH) had laid the groundwork for such a study as early as 1970, but the study was not completed and the results published until 1984. This study, the Coronary Primary Prevention Trial, showed that treatment with a bile acid binding resin reduced major coronary events in hypercholesterolemic men by 19%, with a P value of 0.05. The NIH followed this up with a national Consensus Development Conference on Lowering Blood Cholesterol to Prevent Heart Disease. For the first time, the NIH now went on record advocating screening for hypercholesterolemia and urging aggressive treatment for those at high risk. The Institute initiated a national cooperative program to that end, the National Cholesterol Education Program. For the first time, preventing coronary heart disease became a national public health goal.

Becoming the Framingham Study 1947-1950

In the epidemiological imagination, the Framingham Heart Study has attained iconic status, both as the prototype of the cohort study and as a result of its scientific success. When the Public Health Service launched the study in 1947, epidemiological knowledge of coronary heart disease was poor, and epidemiology primarily involved the study of infectious disease. In constructing their investigation, Framingham's initiators had to invent new approaches to epidemiological research. These scientific goals were heavily influenced by the contending institutional and personal interests buffeting the study. The study passed through vicissitudes and stages during its earliest years as its organizers grappled to define its relationship to medicine, epidemiology, and the local community.

[Coronary risk factors among men and women in Iceland. Results from the Reykjavik Study 1967-1985. 1992]

The Reykjavík Study 1967-1985: Risk factors for coronary heart disease mortality have been investigated in a prospective study of 8001 randomly selected Icelandic men and 8468 women. The men were aged 34-64 and the women 34-76 at the time of their first examination. After followup from 2-17 years 1140 (14.2%) of the men and 537 (6.3%) of the women had died. Coronary heart disease accounted for 43% of the mortality among the men, cancer 27% and cerebrovascular disease 7%. This distribution is in contrast to what was found among the women. Coronary heart disease accounted for 19.4% of the mortality, cancer 42.3% while the relative contribution of cerebrovascular mortality was similar. The effects of various factors were assessed simultaneously with multivariate survival analysis using the Cox's proportional hazard model. Age, serum total cholesterol, triglycerides, smoking and systolic blood pressure were all significant independent risk factors for coronary heart disease mortality in both sexes. Fasting blood sugar was of borderline significance, reaching significance among men, but not among women. However, since the women have much lower risk of dying from coronary heart disease than the men the absolute risk associated with each of the risk factors is much lower in the women.

Switzerland is small in size but big on cardiology

Switzerland is a small country in the heart of Europe and well known worldwide for its Alps, foreign bank accounts, cheese, chocolate and watches. However, it also has made a significant contribution to cardiology, especially interventional cardiology. It was where balloon angioplasty and stenting of obstructed coronary arteries, two of the most stunning advances in cardiology in the last 30 years and the two most frequently performed interventional procedures in cardiology, originated. The author, who recently served as a visiting professor in the University of Geneva, University of Bern and University of Zurich, summarized his personal observations and impressions in this report.

Spanish flu and early 20th-century expansion of a coronary heart disease-prone subpopulation

According to Stephen Jay Gould, "we have a strong preference for seeing trends as entities moving somewhere." However, trends may instead be the product of relative expansions and contractions of different subpopulations constituting the system. Variation in attributes of coronary heart disease cases during the decline in coronary heart disease mortality suggests a change in the primary source-subpopulation of cases over time. It is proposed that an early 20th-century expansion of a coronary heart disease-prone subpopulation, characterized by high serum-cholesterol phenotype and high case-fatality--which contributed to most of the coronary heart disease cases and deaths during the 1960s--may have been a late result of the 1918 influenza pandemic. The same unusual immune response to infection that in 1918 killed preferentially men, whites, and those born from 1880 to 1900 (20-40 years old) may have "primed" survivors of those birth cohorts to late coronary heart disease mortality. Ecologic evidence in favor of a birth cohort and geographic association between both epidemics is presented. Cross-reactive auto-immune response upon reinfection could explain the excess coronary heart disease deaths reported during influenza epidemics from the late 1920s onward. Mimicry between the viral hemagglutinin and the apolipoprotein B or the low-density lipoprotein receptor could be the link between infection and hypercholesterolemia. The extinction of those birth cohorts would result in a relative increase in cases coming from a 2nd subpopulation, which was characterized by insulin resistance and chronic expression of low-grade inflammation markers and was comparatively less vulnerable to die acutely from coronary heart disease.

Advances in the treatment of coronary artery disease

Initial pioneering efforts of direct coronary artery bypass were all performed on a beating heart. Although originally introduced into cardiac surgery for the repair of intracardiac defects, the ability of John Gibbon's heart-lung machine to create a motionless, bloodless operative field catalyzed coronary artery bypass surgery. During the ensuing decades tens of millions of patients benefited from coronary revascularization on cardiopulmonary bypass. As we celebrate the 50th anniversary of the invention of the heart-lung machine the landscape of interventional treatment of coronary artery disease has shifted dramatically. Although instrumental in the genesis of the field of coronary revascularization, the role of the heart-lung machine has now diminished. Two thirds of all coronary revascularization is now performed by percutaneous approaches and one fourth of all coronary artery bypass grafting procedures are performed without the heart-lung machine. However owing to the complexity of patients now requiring revascularization as well as recently introduced incremental improvements to cardiopulmonary bypass including coated, low prime circuits, closed integrated systems, and pharmacologic adjuncts Gibbon's heart-lung machine will continue to play an integral role in this field.