–> Download here the complete AMIP manual!

 

being sick of pulmonary hypertension (IP) means having elevated blood pressure within the pulmonary vessels. This pressure value is different and is not correlated with the systemic pressure that is measured by an instrument applied to the patient's arm. The circulatory system consists of two components: the systemic circle, supplied by the left ventricle, and the pulmonary circle, replenished by the right ventricle. The oxygen-poor blood and rich carbon dioxide, coming from the tissues of the whole body, back to the right heart through two large veins. The blood, from the right ventricle, is expelled into the pulmonary artery and the pulmonary capillaries to allow gaseous exchanges at the level of the alveoli, which are the aerial components of the lung. In order to ensure that the gaseous exchanges take place adequately, the contact surface between the small pulmonary vessels (capillaries) and the alveoli is very wide. For this reason the pressure in the pulmonary circle is about eight times lower than the systemic circulation that brings the blood to all organs (brain, muscles, skin, kidneys, intestines). Pulmonary hypertension is characterized by increased pressure in the pulmonary circle. This condition may be secondary to other diseases: pulmonary, left heart diseases, pulmonary thromboembolism. Pulmonary arterial hypertension (IAP), on the other hand, is a rapidly advancing disease and is caused by widespread obstruction of the pulmonary vessels due to a pathological condition that directly affects the pulmonary vascular system. Idiopathic pulmonary arterial hypertension is defined when no cause can be recognized; More frequent are situations in which pulmonary arterial hypertension is associated with other pathologies: connective diseases (scleroderma, lupus), liver (portal hypertension), viral infections (HIV), congenital heart disease. In these diseases, the pulmonary vessels are largely obstructed by thickening of the wall and by coagulating the blood inside, causing a significant reduction in the pulmonary vascular circle and an enormous increase in blood flow resistance; The pressure in the pulmonary artery can increase by 3-4 times compared to normal values. In this situation the right side of the heart adapts with difficulty to the greater workload, tends to dilate and may not be able to pump an adequate amount of blood into the pulmonary circle. Pulmonary hypertension strongly affects people's lives; The fatigue and the feeling of breathlessness (dyspnea) that accompany it can strongly compromise the conduct of a normal daily life. People affected by the disease complain of respiratory distress, feel a sense of breathlessness for minor efforts or even when they are resting. To the breathlessness is added the problem of fluid retention that manifests, for example, with swelling of the ankles, a sense of heaviness in the abdomen and an increase in the size of the liver. Without diagnosis and cure the IP is a serious disease. Today, with the therapies available, the prognosis has improved significantly, but early treatment remains indispensable. Almost always, unfortunately, it takes about two years before we have a correct diagnosis and proper therapy.  

Idiopathic and secondary pulmonary hypertension

If a pre-existing cardiac or pulmonary disease (such as a heart valve disease, a cardiomyopathy, chronic bronchitis, emphysema, interstitial fibrosis) has resulted in the IP, doctors may say that there is secondary pulmonary hypertension, in As a result of another disease. When the IP was not caused by other known diseases, doctors call it idiopathic pulmonary arterial hypertension (formerly termed "primitive"). In This manual, if it is not indicated differently, the term IP is used to indicate both the one and the other form.  

 

Who gets hit?

Both men and women may be affected by IP but the form of idiopathic pulmonary arterial hypertension is about two or three times more common in women than in men. The disease can begin at any age, at birth or after retirement. It affects people of all races. For unknown reasons it usually involves more women of childbearing age. Forms of pulmonary hypertension secondary to other pathologies are much more widespread than idiopathic pulmonary arterial hypertension.  

 

Inside the lungs

The problem may begin in the cell layer (endothelial cells) lining the small arteries that distribute the blood in the lungs. These arteries are about the thickness of a hair. In the idiopathic IAP we do not know exactly what the cause Sadek the structural change of the wall of the small pulmonary arteries. It could be a damage at the level of the endothelial cells that "irritate" and react by multiplying and producing substances that cause a contraction of the muscle cells that constitute the innermost layer of the wall. If the damage also persists the muscle cells begin to multiply. It can form fibrous tissue replacing part of the wall of the small artery. Unfortunately the process, once started, triggers a vicious circle that feeds itself. As a result of these changes, blood circulation slows down and the formation of clots is more likely, which would make the lung circle even smaller. If we imagine a system of pipes, this means that the liquid has to pass through narrower pipes (pulmonary vessels) and to ensure that the pump (the heart) will have to exert a greater amount of work. The blood vessels in a normal lung form a tree-like design with a broad branching that progressively tapers towards the periphery. In a person with IAP, the narrowing of the vessels causes a pruning of the twigs in both lungs. The pruning effect of the IP on the small arteries of the lungs. Usually a patient with IP will present the pruning in both lungs.  

 

 

Inside the Heart

The heart is divided into four chambers. The room called "right ventricle" pumps non-oxygenated blood into the pulmonary artery, which brings it to the lungs where it oxygenates. From here the blood through the pulmonary veins arrives at the left atrium and fills the left ventricle from where it is expelled in the systemic circulation to reach the various organs (where oxygen is ceded). In the case of pulmonary hypertension, the right ventricle has to work harder to push the blood through the pulmonary circle, where the diameter of the vessels is pathologically narrower than normal. So, as every muscle is subjected to a lot of work, the ventricle gets bigger and its walls thicken. But, the right ventricle is not being able to withstand such a large workload (normally the pressure inside it is only 20-25% of that of the left ventricle) ends up working with less efficiency. When the pressure in the lungs decreases (due to adequate medical treatment or through the cure of the disease that caused the IP) the heart tends to improve its function. When the right ventricle is no longer able to perform its pumping action it can begin fluid retention, especially in the legs, liver and spaces surrounding the lungs. This situation is called "congestive heart failure of the right hearts." The blood pressure is affected by changes to every heartbeat. It has an Acme (systolic or maximal pressure) when the vessel receives the volume of blood and then tends to descend before the next tick (diastolic or minimum pressure). The average pressure is a calculated value that represents the average force that drives the blood into the bloodstream. The average pulmonary blood pressure (PAP) of a healthy person at rest is about 12-14 mmHg. The World Health Organization has defined pulmonary hypertension as an increase in average PAP greater than or equal to 25 mmHg. This reference value should not be confused with systolic pulmonary arterial pressure, which will be expressed by a higher numerical value than the average PAP. The value of pulmonary pressure is not the only parameter to determine the severity of the disease, very important is the ability of the right heart to adapt and function despite the IP.