Pulmonary embolism (TELA) - Classification

Depending on the localization of the embolic process, the following clinical and anatomical variants of pulmonary embolism (PE) are distinguished:

• massive - in which the embolus is localized in the main trunk or main branches of the pulmonary artery;
• embolism of lobar or segmental branches of the pulmonary artery;
• embolism of small branches of the pulmonary artery, which is often bilateral and, as a rule, does not lead to the death of patients.

Depending on the volume of the excluded arterial bed, a distinction is made between small (volume of the excluded bed 25%), submaximal (volume of the excluded bed up to 50%), massive (volume of the excluded bed of the pulmonary artery more than 50%) and fatal (volume of the excluded bed more than 75%) PE.

The clinical picture of pulmonary embolism (PE) is determined by the number and caliber of occluded vessels, the rate of embolism development, and the degree of resulting obstruction of the pulmonary artery bed. There are 4 main variants of the clinical course of pulmonary embolism (PE): acute (“lightning”), acute, subacute (protracted), chronic recurrent.

1. The most acute “lightning-fast” course is observed with a single-stage complete blockage of the main trunk or both main branches of the pulmonary artery by an embolus.

The most severe clinical symptoms are associated with profound disturbances of vital functions (collapse, acute respiratory failure, respiratory arrest, often ventricular fibrillation), the disease progresses catastrophically quickly and leads to death in a few minutes. Pulmonary infarctions in these cases, as a rule, are not detected (they do not have time to develop).

2. Acute course (in 30-35% of patients) - is observed with rapidly increasing obstruction (obturation) of the main branches of the pulmonary artery with the involvement of a greater or lesser number of its lobar or segmental branches in the thrombotic process. The development of pulmonary infarction for this variant is not typical, but it does occur.

Acute pulmonary embolism (PE) lasts from several hours to several days (maximum 3-5 days). It is characterized by a sudden onset and rapid progressive development of symptoms of respiratory, cardiovascular and cerebral failure.

3. Subacute (protracted) course - observed in 45-50% of patients with embolism of large and medium intrapulmonary branches of the pulmonary artery and is often accompanied by the development of multiple pulmonary infarctions. The disease lasts from one to several weeks. Acute manifestations of the initial period weaken somewhat, the disease takes on a slowly progressive character with an increase in right ventricular and respiratory failure. Against this background, repeated embolic episodes may occur, characterized by an exacerbation of symptoms or the appearance of signs of pulmonary infarction. Death often occurs - suddenly from repeated embolism of the main trunk or main branches or from progressive cardiopulmonary failure.
4. Chronic recurrent course (observed in 15-25% of patients) with repeated embolisms of lobar, segmental, subpleural branches of the pulmonary artery, clinically manifested by recurrent pulmonary infarctions or recurrent pleurisy (usually bilateral) and gradually increasing hypertension of the pulmonary circulation with the development of right ventricular failure. Recurrent PE often occurs against the background of cardiovascular diseases, malignant neoplasms, after operations on abdominal organs.

Classification of pulmonary embolism (Yu. V. Anshelevich, T. A. Sorokina, 1983)

Form of pulmonary embolism	Level of damage	Course of the disease
Heavy	Pulmonary trunk, main branches a.pulmonalis	Lightning fast (super sharp)
Medium-heavy	Lobar, segmental branches	Spicy
Easy	Small branches	Recurrent

Severe form of pulmonary embolism (PE) is registered in 16-35% of patients. In most of them, 3-5 above-mentioned clinical syndromes with their extreme severity dominate in the clinical picture. In more than 90% of cases, acute respiratory failure is combined with shock and cardiac arrhythmia. Cerebral and pain syndromes are observed in 42% of patients. In 9% of patients, PE may debut in the form of loss of consciousness, convulsions, shock. Life expectancy from the onset of clinical manifestations can be minutes - tens of minutes.

Moderate form is observed in 45-57% of patients. The clinical picture is less dramatic. The most common combinations are: dyspnea and tachypnea (up to 30-40 per minute), tachycardia (up to 100-130 per minute), moderate arterial hypotension. Acute pulmonary heart syndrome is observed in 20-30% of patients. Pain syndrome is observed more often than in severe form, but is moderate. Chest pain is combined with pain in the right hypochondrium. Severe acrocyanosis. Clinical manifestations last for several days.

Mild form with recurrent course (15-27%). Clinical manifestations are poorly expressed and mosaic, PE is often not recognized, proceeding under the guise of "exacerbation" of the underlying disease, "congestive pneumonia". When diagnosing this form, the following clinical signs should be taken into account: repeated unmotivated fainting, collapse with a feeling of lack of air; transient paroxysmal dyspnea with tachycardia; sudden feeling of pressure in the chest with difficulty breathing; repeated "pneumonia of unknown etiology" (pleuropneumonia); rapidly transient pleurisy; appearance or increase in symptoms of pulmonary heart disease, not explained by objective examination data; unmotivated fever. The significance of these symptoms increases if they are observed in patients with congestive heart failure, malignant tumors, after operations, bone fractures, after childbirth, strokes, when signs of phlebothrombosis are detected.

In 1983, V. S. Savelyev and co-authors proposed a classification of pulmonary embolism (PE), which takes into account the localization of the lesion, the degree of impaired pulmonary perfusion (lesion volume), the severity of hemodynamic disorders and complications of the disease, which determine the prognosis of the disease and the method of treatment.

Classification of pulmonary embolism PE (V.S. Soloviev, 1983)

Localization

1. Level of embolic occlusion:
   • Segmental arteries
   • Lobar and intermediate arteries
   • Main pulmonary arteries and pulmonary trunk
2. Side of defeat:
   • Left
   • Right
   • Double sided

Degree of pulmonary perfusion impairment

Degree	Hagiographic index, points	Perfusion deficit, %
I (easy)	Up to 16	Up to 29
II (medium)	17-21	30-44
III (heavy)	22-26	45-59
IV (extremely severe)	27 and more	60 and more

Complications

• Pulmonary infarction (infarction pneumonia)
• Paradoxical embolism of the systemic circulation
• Chronic pulmonary hypertension