Usually, patients with pulmonary hypertension complain of symptoms such as wheezing (dyspnea) and excessive fatigue, sometimes fluid retention with consequent edemas and heaviness to the abdomen. Symptoms may occur during the course of light exercises or more simply during a walk, but sometimes even at rest. These symptoms are described as ' non-specific ' because they can also be caused by other diseases and not just by IP. Therefore, it is quite difficult to diagnose the IP in the initial phase. Often there is a long period of time between the doctor's first visit and the time when the patient receives specialist care at the hospital. There is no single diagnostic test that accurately indicates the presence of IP; In investigating the origin of anxiety, therefore, it is important to take into account all the diseases that are associated with it, such as diseases of the heart and lungs. The process of investigation leading to the exclusion of other diseases that can cause breathlessness goes by the name of differential diagnosis. For patients with suspected IP there are several initial tests to be taken in order to confirm the diagnosis. The history of the present illness, the anamnesis, the family history, the drugs taken in the past and currently, all have to be discussed in the first interview between the patient and the team of specialists. During the first visit it is necessary to take a general examination of the physical condition of the patient. Other tests used in the evaluation of the patient with suspected IPs may include:
- Electrocardiogram (ECG);
- Chest X-ray (chest RX);
- Echocardiogram (Echo);
- Respiratory function tests (PFR);
- Stress tests and cardio-pulmonary tests;
- Ventilatory and duodenal pulmonary scintigraphy;
- High resolution computed tomography (HRTC);
- Magnetic resonance imaging (NMR);
- Pulmonary angiography;
- Cardiac catheterization.
During the various tests it is possible to have indications that lead to diagnose or even to exclude the IP. Depending on the results, the team of doctors may decide to try a different approach in further investigations.
The electrocardiogram is a non-invasive examination that is used to record the electrical activity of the heart. It is a quick and easy test, its execution takes a few minutes while the patient is lying supine, in resting conditions. The merit of his discovery goes ascribed to William Einthoven, a German physiologist, who in the early 1900s developed the technique still used today in clinical practice. When the heart is electrically stimulated, it contracts. Electrical stimulation is produced by specialized cardiac cells to initiate and conduct (conduction system) such a signal. Normally the electrical stimulation begins at a point located in the upper wall of the right atrium, the sinus-atrial node, and then spreads first to the atria and then to the ventricles. The electrocardiogram records the formation and conduction of electrical impulses that stimulate cardiac contraction. The ECG is recorded by sensors (electrodes) placed on the patient's skin, placed at various points in the chest, arms and legs. These electrodes are connected to a device that measures the voltage. In a patient with pulmonary hypertension, the ECG may show signs of overloading of the atrium and/or right ventricle.
Chest X-ray (chest RX)
The chest radiograph is the result of X-ray passing through the body and allows to visualize both the lungs and the shape and size of the heart. The respiratory system, from a radiological point of view, has a situation of privilege compared to the other apparatuses, it contains mainly air which determines a natural contrast able to highlight, with the simple direct examination, many particulars of this accommodation. The X-ray is carried out with the patient in an upright position between a panel and a photographic plate, on which the image will be etched and developed. Normally two different chest projections are required. In particular, it is resorted to a post-anterior projection (the X-ray beam penetrates from the back and protrudes from the patient's chest, which rests directly on the radiographic cassette) and a latent-lateral. The result of this examination is a radiogram, in which the darker or radiolucent parts (black color) are those with the most air content, while the areas more prone to white or radiopaque are those occupied by the organs (heart, blood vessels, etc.) or by Structures with higher density than air. This examination may provide clues about the presence of various diseases that may cause wheezing (emphysema or pulmonary fibrosis) or may show abnormalities of the heart and the pulmonary circle, some of which are indicative of pulmonary hypertension. However, many patients with early IP have an X-ray of normal chest. Instead, in the most advanced stages of the disease it is possible to observe an enlargement of the right sections of the heart, due to the work overload to which is subjected the left ventricle due to the increase of pressure in the pulmonary artery. It is also possible to observe a dilatation of the pulmonary artery and its main branches, followed by a narrowing of the more peripheral branches ("Potato tree" appearance). In any case, in order to arrive at a more precise diagnosis, more accurate diagnostic tests are necessary, which allow to visualize the parenchyma and the pulmonary circulation better.
The echocardiogram is an examination that allows the visualization of the heart, using ultrasound (acoustic waves with a frequency exceeding 20,000 cycles/second, therefore inaudible to the human ear). The prefix "Eco" derives from the fact that the image obtained from this test depends on the component of the ultrasonic beam that is reflected by the organ or body tissues. The echocardiogram allows to obtain morphological information (dimensions of the cardiac chambers, wall thicknesses, shape and movement of the valvular structures, congenital heart defects) and functional (contractility of the ventricles, blood flows Through the valves, the volume of blood expelled at each beat) often determinant for diagnostic purposes. It can be carried out at rest or under stress and can be trans-thoracic or trans-esophageal depending on what information you want to derive. Trans-thoracic echocardiogram is performed using a gel for the transmission of ultrasound, which is emitted by a small probe (transducer) that is placed on the patient's chest. The sound waves emitted by the transducer are reflected by the structures of the heart and the vessels and are again picked up by the transducer that transforms them into images, visible in a monitor. To evaluate pulmonary hypertension, a trans-thoracic echocardiogram is performed with the patient lying on his side. With this examination one can estimate the systolic pressure in the pulmonary artery (PAPs) by evaluating the speed of the blood regurgitation through the non-continent tricuspid valve (valvular insufficiency). The value of the systolic blood pressure estimation in pulmonary artery should not be confused with the mean value of pulmonary artery pressure (PAPm) measured with right cardiac catheterization. The advantages of this examination are its absolute harmlessness, practicality and rapid execution, the overall cost contained. The main defect is the dependence of the result from the operator's expertise.
Respiratory function Test (spirometry)
Spirometry is a test that provides information on the amount of air that the lungs manage to ventilate, i.e. to move inside (inhale) and outside (exhale). This examination makes it possible to distinguish between obstructive pulmonary diseases, which cause an increase in airway resistance to air passage, and restrictive pulmonary diseases, in which something interferes with the expansion of the lungs. Patients with pulmonary hypertension may have no alteration of respiratory function tests except for a severe reduction in the diffusion capacity of a gas, carbon dioxide (CO). This parameter is an indication of an impairment of lung vessels, typical of pulmonary hypertension.
Stress tests (cardiopulmonary test and 6-minute test)
Patients with IP are usually subjected to different types of exercise. There are various tests that are used to verify if there is a reduced tolerance to the stress and that, at times, provide indications on the causes of the symptoms manifested by the patient. In cases of IP, these tests are often used to measure the tolerance of the patient's effort at the beginning of a therapy and to see if the latter improves or worsens over time. In Some cases the exercise is performed on a rotating mat or on a fixed bicycle, wearing a mask on the nose and mouth (cardiopulmonary test). This exercise allows doctors to measure the use of oxygen by the patient, and indicates the level of efficiency of the cardiovascular and respiratory system in oxygenating the blood and transporting oxygen to the muscles. The stress test can also help you to identify the presence and severity of coronary heart disease and other dysfunctions of the core. The 6-minute March test evaluates the maximum patient distance in 6 minutes. Although not a specific diagnostic test, when used together with careful evaluation of the patient's history and physical condition, it can serve to measure its ability to exercise and determine its functional status during medical treatment . The "Shuttle test" is similar to the 6-minute walk test, but the person must walk back and forth in a 10-metre path at ever-higher speeds, until he accuses Dyspnea. During these tests patients are often required to wear a oximeter placed either on the finger of the hand or on the ear lobe, to measure the amount of oxygen in the blood. In the case of IP, oxygen levels may be reduced below the standard during exercise. In conclusion, stress tests provide doctors with indications of the severity of the disease and are a tool to verify the efficacy of the therapy.
duodenal pulmonary scintigraphy and ventilatory
The study of lung ventilation and perfusion through scintigraphy has an important role in the study of the suspected presence of emboli in the branches of the pulmonary arteries. Pulmonary embolisms are in most cases aggregates of platelets and fibrin that have formed in the veins of the inferior limbs and have reached pulmonary circulation. The presence of clots in the lungs can cause the IP but does not make it certain the diagnosis; Therefore, pulmonary embolism may play a significant role on the decision to carry out further investigations. Pulmonary scintigraphy is conducted in two phases: the first, ventilatory, provides indications on regional pulmonary ventilation and the second, Perfusoria, is used to measure blood flow (perfusion) in all areas of the lung. In the ventilation phase, the patient, through a mask, inhales radioactive gases with particles of size small enough to allow storage in the alveolar spaces. Then the lungs scan allows you to pinpoint the location of these particles (radioisotopes). The dosage of the radioactive substance used is very low. In the phase of perfusion the patient is placed a small needle-cannula in a vein of the forearm, which allows to inject aggregates of marked human albumin, which, because of their diameter, Embolizzano in each lung segment so proportional to blood flow. As the blood flows through the lungs, the machine scans for the positions of the radioactive particles. The V/Q scanning test produces a series of images, showing the lungs from different angles, which help doctors observe the regularity of the flow of air and blood. Under normal conditions you have uniform distribution in all lung segments. In conditions of altered ventilation or perfusion, segmental or non-segmental aspects are observed. The results are classified as low, medium or high probability of pulmonary embolism.
High resolution computed tomography (HRTC) and angiography-TC
With TC (computed tomography), much more detailed images are obtained than normal X-rays. With this technique the image is built on the basis of the attenuation of an X-ray beam in infinite trajectories through the body layer in the studio. Therefore a TC scanner is a special type of X-ray instrument that, instead of sending a single X-ray beam through the body as in normal radiographs, sends various beams simultaneously and from different angles. This allows you to get a better view of the body structures. X-rays cross the body and their absorption is measured by the device. A computer uses this information to calculate the relative density of the examined tissue. Each group of measurements made by the scanner is a very thin section of the body (in this case of the patient's chest). The computer processes the results and projects a two-dimensional image onto the monitor. This examination is also used to rule out certain common lung diseases that might be the cause of wheezing, such as emphysema or fibrosis. During the test the patient lies down on a bed, while the part of the body to be examined is placed in the scanner opening (a ring with a diameter of about 1.5 m). The bed moves in order to allow the acquisition of the various sections of the body that need to be studied. In some cases, before the test, can be injected into the blood of patients a contrast medium that is used to highlight the blood vessels of the body, and in particular the pulmonary ones, and allows to detect any abnormalities of filling. The injection of the contrast medium takes place by means of an agocannula inserted into a vein of the forearm. A minority of patients may be allergic to contrast medium, so before taking the test, you should always communicate any allergic reactions that have previously occurred. The time required for the test depends on the number of images to be recorded and the different angles required. The use of TC in the study of pulmonary pathology is widely justified by the many advantages that the technique offers. Compared to the RX of the thorax allows to visualize anatomic surveys with greater precision, it allows to highlight lesions placed in anatomical districts not well explorable, it allows to identify and to define also very small lesions. The examination does not cause any kind of pain, but one factor to be taken into account is that it involves the emission of larger amounts of X-rays than a normal radiography, so despite being an accurate investigation in the study of the tissue and the pulmonary circulation is Good to use it only in cases of real diagnostic need. In conclusion, the RX of the thorax has an important role, of first instance, in recognizing or at least suspecting the existence of numerous types of pathologies, but TC occupies a role of absolute importance in confirming and deepening the different pathologies.
Nuclear magnetic resonance imaging (MRI)
MRI does not use ionizing radiation (such as RX and TC), but uses magnetic waves and radio frequencies. The absence of radiation allows to repeat the procedure without any major problems. There are also no known dangers or side effects caused by MRI. The examination begins with the patient lying inside a cylinder-shaped magnet that sends radio waves through the body. The scanner collects these signals and a computer transforms them into images. The NMR scanner can photograph almost all tissues in the body, including parts surrounded by bone tissue. During the test a contrast medium can be injected to make the images more visible. The contrast medium differs from the one used in TC for the lower toxicity profile and the greater safety profile. The difference between a normal and an abnormal tissue is often much clearer with MRI than with Ct. Among the investigations for the IP, the MRI is able to show the heart and also the large blood vessels in the surrounding tissue. It also makes possible the identification of some defects of the heart present since birth. MRI can be done in an outpatient regimen and the patient can go home immediately after the examination. During the test it is important to remain completely immovable. As for the TC, the examination could cause a feeling of claustrophobia. Patients who fear these effects must talk to the doctor, who may decide to give them a sedative. In addition, being subjected to a very powerful magnetic field during MRI, patients must not wear jewellery or other metal objects and must warn medical personnel that they are examining the possible presence of electrical appliances such as Cell phones or pacemakers and other metals in the body such as surgical nails or prostheses. The magnetic field generated by the scanner can damage the infusion pumps used for the Flolan or the Remodulen. Therefore it is always good to make sure that the staff is informed that you are wearing a pump. You should never take anything for granted!
Some patients with IP are subjected to pulmonary angiography. This invasive test can be used when the results of the pulmonary scintigraphy or the angiography-TC have not been exhaustive. Pulmonary angiography is the best test available for the diagnosis of any microangiopathies obstructions at the level of the pulmonary circle. During the examination the patient lies down on a table equipped for X-ray scanning and is monitored by electrocardiogram. A thin and flexible tube (catheter) is inserted into the femoral vein through a needle. An operator looking at the monitor positions the catheter in the pulmonary artery and injects a contrast solution that is used to make the lung arteries more visible. Pulmonary angiography produces a series of highly detailed X-ray images (called angiograms) of the pulmonary artery and its branches. The doctor analyses the images in order to detect possible anomalies, such as the presence of microangiopathies (blood clots) or other signs of pulmonary diseases. A small minority of patients who undergo pulmonary angiography may be allergic to the contrast medium used due to its iodine content. Therefore it is a good idea that those who have already developed this type of reaction in the past will present it to the doctor. In addition, pregnant women should be informed about the risks of X-rays for the fetus. However, the risk of X-rays being harmful to the patient is very low and modern equipment is built to provide high quality images using minimal doses of radiation.
Right cardiac catheterization
Right cardiac catheterization allows a direct measurement of the current pressure in the various cardiac chambers, in the pulmonary artery, in the pulmonary microcirculation and provides information on the amount of blood expelled from the right ventricle. The test involves the patient being admitted to the hospital for a few days. If the patient is subjected to anticoagulant therapy with warfarin (a drug that slows down blood clotting) it is necessary to temporarily suspend the administration a few days before; This is to avoid the occurrence of bleeding during the procedure. Sometimes, in addition to right cardiac catheterization, a left cardiac catheterization is necessary to allow the medical team to research any congenital diseases or to evaluate anomalies in the left side of the heart (mitral valve disease, Coronary diseases, etc.). The right cardiac catheterization is the fundamental examination that allows to confirm or exclude the diagnosis of IP and to assess its severity. It also allows to detect the presence of other pathologies that may be the cause of pulmonary hypertension. Just before the procedure begins the patient is given a sedative. Adult patients do not normally receive general anesthesia, which may be necessary for children. The patient is constantly connected to an ECG monitor and a oximeter (which measures oxygen levels in the blood); Systemic blood pressure is also monitored. A catheter is inserted into the femoral vein or jugular vein in the patient, lying down and stationary. The catheter is slowly pushed towards the right atrium, then into the right ventricle and then into the pulmonary artery. The catheter is a tube about a metre long and thin as a spaghetti; It contains three or four lumens inside that allow you to measure the blood pressure at different points. The catheter is positioned through an X-ray display on a monitor. The pressure is continuously recorded by some sensors on the end of the catheter, just as the cardiac output is recorded, i.e. the amount of blood expelled from the heart at each cardiac cycle. By multiplying the heart rate for the cardiac frequency, you also get the cardiac flow value, i.e. the amount of blood eiettata from the heart in one minute. Several blood samples are often collected through the catheter so that specific measurements of the oxygen levels in the various parts of the system circulate thorium. Blood samples also serve to determine the concentration of certain hormones at the level of the pulmonary artery.
Acute vasodilation Test
During cardiac catheterization, an acute vasodilation test can be performed that evaluates whether pulmonary arterioles are able to expand. This test requires that the patient, during catheterization, inhale a gas, usually nitric oxide. If the arterioles dilate significantly, the pulmonary vascular resistance decreases. A large decrease indicates that the vessels are quite elastic and still have a residual amount of vasodilation. This result allows the doctor to decide the type of therapy most suitable for the patient.
Once diagnosed with pulmonary hypertension we assess the severity of the disease depending on the ability to perform physical exertion. A system is to use a "functional classification" that has been standardized for heart patients. This classification is based on the level of activity that the patient is able to endure before having discomfort or symptoms.
(NYHA Class) Class 1: Includes patients who do not have any type of symptom and for whom normal physical activity does not cause fatigue, palpitations, sense of lack of air or chest pain;
Class 2: Includes patients with slight limitation of physical activity that only accuse symptoms after higher than ordinary activity;
Class 3: Includes patients with marked limitation of physical activity that accuse disorders even after mild-grade efforts;
Class 4: Includes patients who experience symptoms even when they are resting.