In 1768, William Heberdeen wrote “There is a disorder of the breast, marked with strong and peculiar symptoms, considerable for the kind of danger belonging to it, and not extremely rare, of which I do not recollect any mention among medical authors.
The seat of it, and sense of strangling and anxiety with which it is attended, may make it not improperly be called Angina Pectoris”.
Neither extremely rare nor very common, he described 20 cases in the Transactions of the Royal College in 1772 and in his clinical practice observed a total of 80 cases, which were published posthumously, in 1802, by his son William Heberdeen jr. On the other hand, as a consequence of the high symbolic importance that all cultures have always attributed the heart, it was thought to be immune to disease, as stated by Pliny the Elder (1st century BC) “the heart is the only internal organ that disease cannot touch and that does not interfere with the sufferings of life”, a concept that still be found in the 18th century. From the Encyclopaedia of Diderot: “diseases of the heart are extremely rare”.
What can have happened if, little more than two centuries later Jean Pierre Bassand, in the inaugural lecture of the 2004 European Society of Cardiology Congress in Munich, said: “The entire planet is threatened by a pandemic of cardiovascular diseases able to kill more people than the Black Death in the Middle Ages”? How can we not agree with him when cardiovascular diseases cause one in three deaths worldwide and one in two in Western countries and the forecasts for the future are far from encouraging?
Artery walls are composed of a number of layers: an inner layer known as the tunica intima that comes into contact with the blood, an intermediate layer that is rich in the smooth muscle cells responsible for the tone of the artery wall, so the vessel does not collapse, and an outer layer known as the adventitia whose main function is to supply the vessel wall with nutrients.
Ischaemic cardiomyopathy (angina pectoris in its chronic form and myocardial infarction in its acute form) is the result of a narrowing or obstruction of the lumen of a coronary artery (the blood vessel that supplies the heart) due to the more or less extensive presence of a formation known as an atherosclerotic plaque.
An atherosclerotic plaque consists primarily of lipid material (fat and cholesterol); as it grows, it progressively narrows the diameter of the arteries, resulting in a decrease in blood flow and consequent decrease in the oxygen supply to the tissues; oxygen is indispensable for transforming the crude substances that reach the blood from food (fats, sugar and so on) into energy. The heart and brain, in particular, are organs that function constantly and therefore require a great deal of energy that is provided to them through mechanisms involving the use of high-performance substrates with a low toxic residue. In order to work, this mechanism requires oxygen and a deficiency of oxygen in these organs causes damage and, ultimately, destruction.
Fig. no.1: Lumen of a coronary artery that is partly occupied by an atherosclerotic plaque, whose core (in white) is constituted by lipid material covered by a fibrotic hood. Although the blood flow through this vessel is reduced, the symptoms of oxygen deficiency will only appear when the heart requires more energy for greater performance.
Fig n.2: In this case, the vessel lumen is blocked by the presence of a thrombus (in red) that has formed due to the rupture of the plaque. Blood flow through the vessel is now completely cut-off: the heart tissue is deprived of oxygen and is destined to die very shortly (necrosis, myocardial infarction).
But how do plaques form, what is the “primum movens” of this pathological process?
It all starts with dysfunction of the intima, which is the result of a series of metabolic, haemodynamic, neurohormonal, toxic, inflammatory and genetic factors known as risk factors.
A great many factors have been identified as contributing to the atherosclerotic process and in recent years risk quantification guidelines have been drawn up. Some risk factors are currently unmodifiable, in that they are associated with the individual’s genetic make-up, whereas other risk factors can be mitigated; however, the presence of the former further increases the importance of the latter.
Many of the environmental risk factors are a consequence of lifestyle and are associated with dietary and recreational habits, occupational and interpersonal stress, personality traits and exercise.
These are the factors that tend to increase while those associated with underdevelopment decrease.
However, globalisation makes negative behaviour homogeneous, so that the main disease risk factors are the same in the different income classes.
Age becomes an aggravating factor as the incidence of hypertension, dyslipidaemia (changes in fats) and diabetes increases with age group.
Many resources are employed to reduce the presence of these conditions in the population. However, the results that we are achieving are sub-optimum and although there has been a reduction in acute event mortality as a consequence of better diagnostic and therapeutic skills, less is being obtained in terms of the incidence of the disease.
Where are we going wrong with prevention?
If we use a pyramid to represent the relationship between risk factors and disease, placing at the base the factors that characterise a Western lifestyle, such as a qualitatively and quantitatively incorrect diet, sedentary habits and tobacco smoking, and clinical outcomes at the top, and place the disease factors deriving from the base in the middle, by looking at the intervention strategies we realise why the results obtained are only partial and have an economic cost that becomes increasingly unsustainable for a public health service. The reason is that we have chosen to intervene primarily in the middle of the pyramid, rather than at the base.
The most recent results of the EuroASPIRE III survey provide a bleak outlook: despite the vast range of medicinal products available for the primary and secondary prevention of cardiovascular events, there are still a great many patients with or without known coronary disease who do not achieve the targets indicated by guidelines regarding cardiovascular risk factors, and this number is on the increase.
The ESC (European Society of Cardiology) promoted the first EuroASPIRE survey about 15 years ago, in 1995-1996, involving 9 countries. This was followed by a second survey, in 1999-2000, involving 15 different nations. Both surveys showed a high prevalence of modifiable risk factors in patients with coronary disease. The most recent survey, EuroASPIRE III, which was conducted in 2006-2007 in 76 centres in 22 countries, showed that over the years, there have not been any great improvements in terms of cardiovascular prevention. In actual fact, an analysis regarding eight nations that took part in all three editions of EuroASPIRE, which was published in the Lancet in March 2009, revealed that the management of lipid and pressure levels in patients with coronary disease is still sadly sub-optimum, despite the availability of new pharmacological options.
Intervening at the base means changing the lifestyle of a community, making very specific health and hygiene-related choices that often conflict with important market interests, and promoting health education campaigns from the very earliest years of school. Intervention in the middle of the pyramid is politically less demanding as it primarily, if not exclusively, involves the use of medicinal products that act selectively against cholesterol, hypertension, diabetes and thrombosis, but not on the conditions that cause them. There are pleiotropic effects of lifestyle that are independent of pharmacological treatments.
And the results are extremely positive.
For 16 years, doctors at Harvard University monitored approximately 45000 male subjects of between 40 and 70 years of age: the lifestyle of each man was quantitatively defined by the sum of 5 factors considered as not favouring cardiovascular disease, such as not smoking, a body mass index of < < 25 Kg/m² (calculated as weight in kg divided by height), moderate to strenuous exercise (≥ 30 min/day), moderate alcohol consumption (between 5 and 30 g/day), a diet constituted predominantly by fresh fruit, cereals, and plant products, with fish and chicken consumption more than 2.5 times greater than that of red meat and a polyunsaturated to saturated fat ratio of 0.6. This gave a lifestyle score of between 0, unhealthy (no factor present) and 5, very healthy (all 5 factors present). The higher the lifestyle score during the observation the lower the risk of having a coronary event (myocardial infarction). This behaviour was no different if during the observation certain subjects took a medicinal product to lower their blood pressure or cholesterol.
However, reality is very different, as is shown by the obesity trends for the last 25 years in the USA and Europe.
1985-2000 OBESITY TREND FOR ADULTS
The extent of the replacement of yellow cards with red ones is remarkable and the situation for obesity in children and teenagers is even more dramatic, and is particularly severe in Italy (purple). Or how little people exercise, despite knowing that the greatest benefit in terms of a reduction in risk factors regards, first and foremost, obese subjects.
The advantages of giving up smoking is clearly shown by this study by G.Cesaroni (“Effect of the Italian Smoking Ban on Population Rates of Acute Coronary Events”, Circulation 2008;117:1183-1188): 5 years after the ban on smoking, the risk of myocardial infarction has decreased to one fifth and the risk of stroke by half.
Prof. Luciano Daliento
Former Professor of Cardiology
Senior Scholar Università di Padova