Algorithms for the diagnosis and treatment of idiopathic pulmonary arterial hypertension

Background. Pulmonary hypertension (PH) is a hemodynamic and pathophysiological condition characteri-zed by an increase in the average pressure in the pulmonary artery > 20 mm Hg and is evaluated according to the data of the right heart catheterization (RHC). In most cases, PH is not an independent disease but is a manifestation of other diseases. Idiopathic pulmonary arterial hypertension (IPAH) is a diagnosis that it is established by excluding all other causes of PH (damage to the left heart, connective tissue diseases, HIV infection, lung diseases, portal hypertension, congenital heart defects, a history of pulmonary thromboembolism, etc.). In IPAH, the etiology of the disease is unknown. Pathogenesis and symptoms of PH. Vasoconstriction, microthrombosis, and vascular remodeling are the three main pathophysiological elements in PH. Symptoms of PH are non-specific: shortness of breath, rapid fatigue, chest pain during physical exertion, and sometimes syncopal states are observed. Decompensated patients have signs of right-sided heart failure (edemas, ascites, bloating, pulsation of the jugular veins). Diagnosis. The diagnostic algorithm for РH consists of two stages. The first one is located outside the expert сenter, and the second one is located directly in the PH expert center. When this disease is suspected and there are typical symptoms and signs, all patients undergo an echocardiographic examination. Then, under certain conditions (for example, the absence of the underlying cause of PH), the patient is referred to the PH expert center, where it is possible to conduct RHC. Evaluating the prognosis. Evaluation of patients with IPAH is necessary to improve disease control and transition from a higher risk to a lower one. Prognosis assessment is comprehensive and is determined based on clinical status, symptom progression, syncope, results of a 6-minute walk test and NT-proBNP, results of examination methods (cardiopulmonary exercise test, echocardiography or MRI of the heart, hemodynamic assessment). Treatment. The main objectives of IPAH treatment are reducing the severity of symptoms, slowing the progression of the disease, improving the quality and increasing the life expectancy of patients. First of all, these are general measures (physical activity, prevention and management of pregnancy), prevention of infectious diseases, social and psychological assistance, monitoring compliance with the regime, recommendations for travel/journey, maintenance therapy (oral anticoagulants, diuretics, digoxin, oxygen therapy). Patients with a positive vasoreactive test are prescribed with calcium channel blockers. In all other patients, specific PH therapy may include prostaglandins (inhaled, intravenous, and subcutaneous forms), prostacyclin receptor antagonists, endothelin receptor antagonists, phosphodiesterase-5 inhibitors, and soluble guanylate cyclase stimulants. Surgical treatment. One of the options for surgical treatment of IPAH is atrial septostomy — the creation of a perforation in the atrial septum. This leads to decompression of the right chambers of the heart and increases the preload on the left ventricle, which leads to an increase in cardiac output. In case of ineffectiveness of all the above methods of treatment and significant progression of the disease, patients are indicated for lung transplantation or heart — lung complex.