Pulmonary Hypertension: What It Is, Why It Occurs, Symptoms And Treatment

Pulmonary hypertension is a serious disease that affects the quality of life as it reduces the overall performance of the affected person. Another downside is that it shortens the patient's life expectancy.

The essence of the disease is high blood pressure in the pulmonary stream.

It is more common in other diseases, but in some cases its cause is not always known.

The course of the disease depends on several factors. Proper and timely treatment can prevent the rapid progression and death of the affected person caused by a true heart failure.

In 1891, the German physician Ernst von Romberg:
The first written mention of pulmonary artery sclerosis.
It is thought to have been primary pulmonary hypertension.  
The term was introduced in 1951 by David Dresdale.

Introduction to the Heart and Pulmonary Circulation

The heart is a muscle pump that pumps blood into the bloodstream.

From a practical point of view, there are two types of blood circulation: minor and major.

Let's start with the major circulation.

Major or systemic blood circulation ends with two large veins: the upper and lower vena cava, which supply deoxygenated blood to the heart.

It is the blood from which oxygen was consumed by the body's cells. Blood must be enriched with oxygen so that it can be expelled back into the systemic blood circulation. Oxygenation occurs in the lungs.

A few facts:

1. blood vessels that carry blood towards the heart are called veins
2. blood vessels that carry blood from the heart are called arteries
3. the largest artery is the aorta
4. the heart has 4 cavities, sections:
   • right atrium
   • right ventricle
   • left atrium
   • left ventricle
5. heart activity never stops

The blood returned to the heart, more precisely to its right half.
The beginning of theminor blood circulation - pulmonary circulation.

Blood enters the right atrium. From there it continues towards the right ventricle.

It is expelled from the right ventricle through the large pulmonary artery into the lungs. In the lungs, the blood is saturated with oxygen.

Oxygen binds to hemoglobin. This is the red blood cell pigment of the red blood cells.

1 gram of hemoglobin can carry 1.34 milliliters of oxygen.

It continues from the minor - pulmonary circulation.

From the lungs, blood passes through the 4 pulmonary veins into the left atrium. It does not stay here long and continues to the left ventricle.

Major - system blood circulation.

From the left ventricle, it is expelled with great force into the major blood circulation. This is due to the systole of the left ventricle, i.e. when it is contracted = expulsion of blood from the heart cavity.

Conversely, the term diastole means a relaxing of the heart cavities and blood suction.

Systole and diastole are two phases that alternate. This ensures that the heart works as a pump. Oxygen carries oxygen, blood components, nutrients and other important substances for the preservation of life.

And...

During the flow of blood in the heart, it is necessary to mention the heart valves.

The heart is a muscular organ.
The heart muscle, or myocardium, is a powerful unit.
It is the thickest layer of the heart wall.
It is located in the mid section.

From the outside, the muscle is covered by the epicardium. And the heart is stored in the pericardium, i.e. the sac containing the heart.

The inner surface of the heart is covered with a thin membrane called the endocardium. The endocardium passes smoothly to the blood vessels. However, the important information is that it also forms heart valves.

Heart flap = one-way valve that lets blood forward. 
But it prevents the blood from flowing backwards.

Various valve diseases cause pathological blood flow back to the previous heart compartment. This negative phenomenon results in a reduction in the body's oxygenation and an overload of the heart muscle.

What a possible and serious consequence is heart failure.

Learn more in the following articles:
Heart valve diseases
And about inflammatory endocardial disease in the article:
Endocarditis

Minor Blood Circulation

The blood pressure in the pulmonary circulation is relatively low. Under normal conditions, it does not exceed 25 mm Hg, i.e. millimeters of mercury, and the mean pressure in the lungs is about 15 mm Hg.

Even at such a low pressure, it is possible to increase the blood flow through the lungs several times, without excessive pressure increase. This helps especially with increased physical activity when a sufficient supply of oxygen to the body's cells is needed.

In left ventricular systole, blood is expelled into the aorta. Then the blood pressure rises above 80 mm Hg.

The height of the systolic pressure is 120 - 140 mm Hg as the upper limit.

And the pressure in the right ventricle is 20 to 30 mm Hg.

Want to know more about pulmonary hypertension?
What causes it? 
How does it manifest and how is it treated?
Continue reading...

Pulmonary Hypertension is Defined as...

...high blood pressure in the pulmonary circulation.

The definition goes like this:

Pulmonary hypertension (PH) is a hemodynamic and pathophysiological condition in which the mean pulmonary pressure is equal to or greater than 25 mm Hg. And in peace.

In pulmonary hypertension, blood pressure values are:

1. systolic pressure above 35 mm Hg
2. mean pressure above 25 mm Hg
3. diastolic pressure above 12 mm Hg

Mean arterial pressure = average blood pressure in an individual during a single cardiac cycle.

Pulmonary pressure is measured during right-sided catheterization,

so, it is an invasive method of measuring blood pressure.

• normal pulmonary pressure has an upper limit = 20,6 mm Hg
• vaules 21 - 24 mm Hg are not precisely classified (limit / risk values?)
• mild PH = 26 - 35 mm Hg
• moderate PH = 36 - 45 mm Hg
• severe PH more than 45 mm Hg

An invasive method is needed for diagnosis, and thus a measurement of pressure during right heart catheterization.

But...

It can be derived by estimation in Doppler echocardiography. It is determined by the speed of the regurgitation nozzle on the tricuspid valve at a value higher than:

3,0 to 3,5 m/s = pulmonary artery pressure greater than 40 mm Hg.

In pulmonary hypertension, the cause of the difficulties is an increase in circulatory pressure above 25 mm Hg. This increases the strain on the right ventricle, which is not adapted to overload in the long run.

Blood accumulates in the right ventricle and is insufficiently pumped to the left heart. The acute course of the disease is manifested by dilating,or extending,the wall of the right ventricle. This condition is called vasodilation.

Slowly increasing resistance and blood pressure against the right ventricle gives time to adjust, the heart muscle then thickens and increases its volume. The right ventricle is hypertrophic.

Changes in the heart muscle are called cardiomyopathy.

Both of these conditions lead to right ventricular failure.

The exact cause of pulmonary hypertension is not always known. It is then referred to as primary or idiopathic.

Another group consists of diseases that cause secondary pulmonary hypertension.

Several factors play a role in the development of the disease.

Genetic influence, heredity, family history (rare) are all involved. There are also other associated risk factors.

For example, the use of certain medicines, such as weight loss and appetite suppressants, even after several years. Also the effect of toxins or radioactivity.

It can occur in liver disease, thyroid disease and rheumatic diseases, inflammation of the blood vessels or HIV.

It most often occurs in left heart disease and dysfunction, such as left heart failure and aortic or mitral valve involvement.

= roughly 75 %.

The second most common cause is a lung disease, called chronic obstructive pulmonary disease, or COPD.

The acute form is usually caused by embolization into the lungs.

= roughly 10 - 15 %.

For example...

Pulmonary arterial hypertension stems from a narrowing of the blood vessels of the pulmonary system. This increases the blood pressure in the lungs, which the right ventricle must overcome to meet the requirement for blood supply to the body.

The classification into a primary and a secondary form is somewhat outdated. Today, high blood pressure in the pulmonary circulation is classified according to several conditions, such as etiopathogenetic, clinical or therapeutic aspects.

Table: Classification of Pulmonary Hypertension

Another form is based on the classification according to hemodynamics and pathophiosiology:

1. precapillary pulmonary hypertension = normal pulmonary wedge pressure
2. postcapillary pulmonary hypertension - increased pulmonary  wedge pressure
3. hyperkinetic pulmonary hypertension - in congenital conditions, such as persistent ductus, but also in increased cardiac output, as in hyperthyroidism

Measuring pulmonary wedge pressure? What is it about?

Left atrial pressure = vascular pressure on the venous side of the circulation.

However, the pressure in the left atrium is difficult to measure with the invasive method.

Therefore, it is derived from the pulmonary capillary wedge pressure. This is the pressure that is measured in the invasive method, i.e. right-sided cardiac catheterization, namely at the level of the last vessel in which the pressure catheter wedges is stuck.

The wedge pressure is 5 mm Hg.

Table: forms and some causes of Pulmonary Hypertension

The symptoms of pulmonary hypertension are not always detected at the early stage. In most cases, they are non-specific, which contributes to the number of late diagnosed cases.

Problems usually appear when the increase in pressure in the pulmonary circulation is elevated.

Table: Some Observable Symptoms

The presence of symptoms is individual. Of course, it also depends on the associated underlying disease. Individual problems either appear in a combination or do not occur at all.

Diagnosis of the disease is demanding and is based on various diagnostic methods.

First, the medical history and clinical picture (i.e. manifestations), an examination of physiological functions, such as blood pressure, pulse, blood oxygen saturation are checked. Auscultation of the respiratory system, evaluation of breath, heart sounds and the presence of murmurs are important.

The basic test kit also includes X-rays, laboratory blood tests, and ECG.

Another basic examination is an echocardiogram. Echocardiography is an ultrasound examination of the heart, which determines the size of the heart, its compartments, diagnoses birth defects, valve defects, the condition of large vessels and other functions.

Doppler ultrasonography has diagnostic importance - Doppler echocardiography.

Other methods of exanination include:

• stress tests
• 6-minute walk test
• ergometry
• spirometry
• CT
• MRI
• pulmonary angiography
• coronary catheterisation
• during a differential diagnosis and examination:
  • reumatological 
  • pneumological
  • gastroenterological
  • hematological

Right Heart Catheterisation

During this method, a catheter is inserted into a large vein.

The catheter passes through the right heart to the pulmonary stream until the final wedge in the peripheral branch of the lung.

In this case, it is important to measure blood pressure in:

• the right ventricle
• pulmonary artery
• capillary wedge = left atrial pressure

At increased pressure in the lungs + with a normal value in the wedge
= e.g. embolisation. 
At increased pressure in the lungs + increased pressure in the wedge
= left heart failure.

In addition, other parameters such as cardiac output per minute and overall hemodynamics can be monitored with this method.

The course of the disease depends on the degree of increased blood pressure in the pulmonary stream.

The underlying disease also has an effect on the overall condition.

The course of the disease rarely takes a primary idiopathic form.
It is more frequent than the secondary form, for example due to left heart failure and chronic lung disease.

The acute condition worsens with pulmonary embolism when an obstruction in the pulmonary circulation increases the pressure in the right ventricle. If left untreated, its function will eventually fail, which can lead to death.

Over time, cor pulmonale develops.

The disease does not always manifest itself in the initial stage.

Usually, the disease is detected at a later stage. Then the value of pulmonary blood pressure is increased to twice the normal values of pressure.

A characteristic phenomenon is associated difficulty breathing, which occurs during the first moments mainly during increased exertion, for example, doing exercises, sports activities, running, walking up the stairs.

The disease is characterized by progression, i.e. a deteriorating condition.

Later on, shortness of breath may occur during normal daily activities and even when there is no exertion at all, which is referred to as shortness of breath in rest.

The first non-specific signs include fatigue and increased exhaustion.

In case of frequent fainting, dizziness and physical weakness, which is accompanied by a feeling of fainting = states of pre-syncope.

It is necessary to determine the cause.

Associated difficulties also include progressive swelling of the lower limbs. First around the ankles, eventually on the forelegs. In the late stage, the swelling of the abdomen or the whole body is also associated.

Chest pain or a feeling of pressure also occurs due to reduced blood flow to the heart muscle, it is described ...

The feeling as if someone is sitting on my chest.
My chest feels heavy. 

Of course, as already mentioned, the overall picture of ongoing problems is individual and largely depends on the primary diagnosis.