EMC - Cardiologie-Angéiologie最新文献

The world medical community and the cardiologists are gaining awareness of the increasing danger of metabolic syndrome. Its prevalence varies widely according to the studies, with and incidence of 16 % in men and 11 % in women in France for the DESIR study. The major abnormality seems to be the increase of central fat, that is responsible for an increase of free fatty acids delivered to the liver, and an insulin resistance. Those two abnormalities are then going to induce a cascade of abnormalities dealing with numerous atheromatous risk factors. Then will appear high triglycerides, a low HDL, small dense LDL, an increase of blood pressure, a shift of coagulation parameters toward a pro-thrombotic state, an insulin resistance, an increase of CRP, an activation of cytokines and adhesines, an endothelial dysfunction, an oxydative stress. The metablic syndrome has two major complications, the cardio-vascular complications that are increased by a factor of 2 to 3, and the risk of evolution toward non insulin dependant diabetes who will by itself increase the cardio-vascular risk, with depending of the studies a relative risk of evolution toward NIDDM of 10 when the metabolic syndrome is present. The major interest remains however to isolate the high risk patients in the population, who are the most concerned by the prevention measures.

Hypertension is the most frequent cardiovascular disease in our countries. Exercise training lowers significantly systolic and diastolic blood pressure. Consequently, all currently available guidelines recommend exercise training together with other non pharmacologic interventions in mild hypertension and as an adjunct to pharmacologic treatment in more severe hypertension. Furthermore, in patients at low cardiovascular risk, initiation of drug therapy should be considered only after pharmacologic approaches have been tried for 6 to 12 months. Pre-training assessment requires a specific clinical evaluation and a resting electrocardiogram. Exercise testing and echocardiogram should be performed, depending on the severity of hypertension, age and cardiovascular complications. Endurance training is the preferential exercise, from low to moderate intensity (40 to 85% of maximal oxygen consumption). Resistance training, particularly the “circuit weight training”, at 30-50% of maximum capacity, reduces blood pressure without adverse effects; heavy resistance training should be postponed until blood pressure is under control. Physicians should give a detailed exercise prescription and follow-up to improve compliance and motivation.

Dissections of carotid and vertebral arteries are a common cause of stroke in young adults (about 20%). They are characterized by the occurrence of local signs (mainly head and cervical pain, and Horner's syndrome) followed by ischemic stroke, which can be devastating. Most of these strokes occur within one week after local symptoms and signs, but can occur as late as one month later. Therefore, when a cervical artery dissection is suspected, noninvasive investigations should be performed in emergency so that appropriate treatment is initiated early enough to prevent severe ischemic stroke.

Because of its high frequency and mortality rates, myocardial infarction has a particular place among cardiovascular diseases. Its rising incidence and mortality rate (proportional to living standards) have been studied in large trials such as the MONItoring of trends and determinants of CArdiovascular disease (MONICA) project, initiated by the World Health Organization, which has brought to light the great geographical disparity of the disease throughout the world and in each studied country, with, most of the time, a North-South gradient. There is also a temporal dynamics specific of the epidemiology of myocardial infarction: in some countries, the disease is receding, but in some others, its frequency is alarmingly increasing. Among all the determining factors, some cannot be modified, such as age, gender, heredity or clearly identified previous history. However, some others can be modified, like hypertension, dyslipidaemia, smoking, nutrition, socio-economical and environmental conditions. All these factors are strongly related to the incidence of the disease. More recent theories such as vitamin deficiency or genetic particularity still need to be confirmed, but they constitute new research subjects since they could induce therapeutic progress and means for primary and secondary prevention.