Cardiovascular diseases

There are many diseases that affect the heart and arteries but four are particularly prevalent. Myocardial infarction (destruction of heart cells) is linked to damage to the coronary arteries (which provide blood to the heart) in 90% of cases. Strokes occur as a result of impaired blood flow to the brain linked to a hemorrhage or a blockage of the arteries that supply blood to the brain. Heart failure (impaired cardiac function) is mainly linked to various changes in cardiovascular tissues, most often the result of ageing. Hypertension (high blood pressure) is defined as the sustained elevation of arterial blood pressure in comparison to what is considered to be the “normal” value (140/90 millimeters of mercury). There is a wide range of long-term consequences: heart failure, stroke, kidney failure, etc.

Impact on public health

Cardiovascular diseases are the number one cause of death in industrialized countries. In 2002, they affected 147 million people throughout the world in 2002 and resulted in over 16 million deaths. Among them, coronary pathologies alone (angina, myocardial infarction) affected 58 million people and killed seven million, whereas 49 million people were victims of strokes, which were fatal for 5.5 million of them. Cardiovascular diseases not only have a major impact on individuals and their quality of life in general, but also on public health costs and the countries’ economies. Risk factors for these pathologies include diabetes, smoking, family history, obesity, high cholesterol, etc.

Diagnosing myocardial infarction

It is essential to begin treatment as early as possible. Short-term prognosis depends on it.
- Clinical signs: intense pain in the middle of the chest that may spread to the arms and the jaw, drop in blood pressure, accompanied by sweating, nausea, shortness of breath, etc.
- Additional tests: electrocardiogram, echocardiogram, coronary angiography.
- Biological analyses: detection of the quantity of certain substances released into the blood when heart cells are destroyed. Depending on the substance, increased amounts may be detected at different points in time and may or may not remain in the blood. Diagnoses are made on the basis of the combination of these different biomarkers and the changes in their respective levels. Myoglobin is produced (not exclusively) by heart cells. Its early increase (two hours after the onset of an infarction) supports the diagnosis of infarction. Moreover, measuring myoglobin is useful for monitoring patients following thrombolytic therapy. CK-MB is also a marker that appears early on but may also increase in other clinical situations. Troponin I is specific to heart cells and can only be detected in the blood under pathological conditions. It has the dual advantage of appearing early on (3rd hour) and remaining in the blood for several days (three to seven days).