Outline of hospitalization due to venous thromboembolism in the state of bahia between 2010 and 2020

Diseases of the cardiovascular system have been seen for many years as important factors in the population's illness. According to data from the Ministry of Health, in 1999, such comorbidities led to approximately 1,100,000 hospitalizations through the Unified Health System 1. Within this scenario, Venous Thromboembolism (VTE) stands out, a pathological condition marked by the development of a clot in the veins, which leads to impairment of blood circulation.

The physiological changes that precede venous thromboembolism are grouped by Virchow's Triad, which encompasses endothelial lesions, stasis or turbulent blood flow, and blood hypercoagulability. Injury to the endothelial cell is a procoagulant factor, as it increases the expression of thrombomodulin, a thrombin modulating agent, stimulating platelet adhesion. Hemodynamic alterations, such as stasis and turbulence, by modifying normal blood flow, stimulate contact of platelets with the endothelium of vessels and reduce the elimination of coagulation factors, by decreasing flow. The state of hypercoagulability, which can have hereditary and genetic causes, also promotes an imbalance between clotting factors by activating procoagulant substances and inhibiting anticoagulants. two

VTE has two distinct clinical presentations, which are closely related: Deep Vein Thrombosis (DVT) and Pulmonary Thromboembolism (PTE) 3. DVT consists of the formation of clots in the deep veins of the lower limbs, which have the potential to reach the pulmonary circulation 3. This mechanism results in PTE, a condition marked by the migration of an embolus to the pulmonary circulation, which compromises the irrigation of this organ and is generally associated with a more serious situation 4.

Manifestations in Deep Vein Thrombosis are pain, heat, redness, swelling of the affected limb, cramps and, in some cases, greater predisposition to the formation of ulcers 2-5. The edema, due to the venous obstruction, is normally of the tense type, causing a swelling, only in the calf or in the whole affected leg. The redness, heat and pain at the site are caused by inflammation of the vessel wall. The pain may be permanent or be related to orthostasis or physical exertion, such as the Hormans Sign, in which the foot is dorsiflexed to assess whether there is severe pain in the calf 6. However, certain patients may not have symptoms or only some of them 5. Pulmonary embolism is characterized by distinct manifestations, namely: chest pain, usually of a pleuritic nature, tachypnea, dyspnea on exertion and in some cases cough 5. In more serious situations, dyspnea at rest, hypotension and syncope, due to low cardiac output and hypoxemia 5. Cases of pulmonary infarction are uncommon complications and, when they exist, are associated with extensive events and previous diseases or comorbidities, such as pulmonary infections and heart failure 7.

The diagnosis of venous thrombosis is complex, as no sign or clinical manifestation presented by the patient is predictive for confirmation or exclusion of condition 8. Thus, the patient is classified according to the pre-test probability (i.e. [suspected presence of a certain disease based on anamnesis, physical examination findings and epidemiology 9]) through validated risk assessment models for deep vein thrombosis or pulmonary embolism using the Wells or Geneva diagnostic criteria, which have similar diagnostic accuracy 10. These scores are important, as they eliminated situations of intermediate probability, dichotomously characterizing patients into situations of low probability (“probable PTE”) and high probability (“unlikely PTE”) 5,10.

This predictive model can be complemented using other tests such as D-dimer. Its values can be measured in whole blood or plasma, however it should be noted that complementary tests are only performed when it is not possible to confirm the suspicion of VTE with clinical examination, which occurs in most cases 11. As it is highly sensitive ( 95%) 10, but little specific (40%) 10 for VTE, its use is related to its high negative predictive value 5 (i.e. [probability of disease absence when the test is negative])9. Thus, if the result is negative, the diagnosis of VTE can be excluded in patients with a low to moderate pre-test probability of DVT or embolism 5. However, in situations where there are strong indications of a case of VTE , treatment can be started even without the results of complementary exams 12. Treatment consists of three main categories 13: medication (use of anticoagulants paying attention to the risk of bleeding 14) thrombolysis (through an injection of a substance into the bloodstream of the patient)15,16 and vena cava filter (the insertion of devices in the inferior vena cava, indicated for patients with DVT who cannot use anticoagulation)17.

Thus, the presentation of signs and symptoms, which are often nonspecific and common to other pathologies, as well as clinical diagnoses with specificity lower than 50%, lead to underreporting of the disease 18. As a result, knowledge of the disease is significantly hampered. real incidence of venous thromboembolism.

Due to this worldwide epidemiological problem, estimating the prevalence of VTE is a challenging task, and for this reason, the numbers are variable. In the United States (USA), for example, it is estimated that the prevalence of PTE is between 3.4% and 14.8%, while in Asia, this number is around 2.0% to 4. 7% 19. In Brazil, in turn, the numbers that characterize the epidemiology of VTE are also not very precise. According to certain references, the incidence of the disease is 1 to 2 episodes per 1000 inhabitants 18, while others describe it as 0.6 per 1000 inhabitants.20

The analysis of the relationships between VTE and different health variables also allows understanding the impacts of this disease on the Brazilian population. From an epidemiological study carried out at the Hospital das Clínicas of the Federal University of Uberlândia, MG, between September and December 2005, it was concluded that the most frequent risk factors found for VTE were prolonged surgery (85.2%), anesthesia general (46.2%), age equal to or above 60 years (42.3%), prolonged restriction to bed (27.4%) and age between 40 and 59 years (24.9%) 20. age and factors that promote immobility are crucial for the development of VTE. There are also the following variables intrinsically associated with the prevalence of VTE: obesity, increasing the risk by 2 to 3 times, in cases of BMI greater than 30Kg.m2; 21 neoplasms, with an increase in risk of 5 to 7 times 22; in addition to pregnancy (increase in risk by 10 times) and the puerperium (25 times).23