Pulmonary hypertension

The pulmonary circulation distributes blood from the heart to the lungs through a low resistance, high compliance system. In normal situation, the pressures are lower than in the systemic circulation. It can be a primary process (Primary Pulmonary Hypertension) or appear in the bosom of other pathologies, respiratory or not, then being called Secondary Pulmonary Hypertension.

Primary pulmonary hypertension

It is pulmonary hypertension of unknown cause, which is characterized by the alteration of the small muscular arteries of the lung, observing characteristic pathological alterations in the pulmonary arterioles. It predominantly affects the female sex and its highest incidence is between the 3rd and 4th decade of life.

Secondary pulmonary hypertension

Due to various diseases, among which are Chronic Obstructive Pulmonary Disease (copd) and Pulmonary Thromboembolism (PE). In both situations, there is an increase in the resistance of the pulmonary circulation with the consequent overexertion of the heart to maintain blood flow. In sustained cases, this overexertion of the right heart secondary to pulmonary hypertension is known as cor pulmonale.

Symptoms

The most frequent symptom is respiratory distress, which is usually characterized by being exertional and progressive, especially in cases of primary pulmonary hypertension and copd. Likewise, asthenia and syncope can also be observed with exercise.

The clinical manifestations of PE are totally nonspecific. The most frequent symptoms are dyspnea (which usually appears acutely) and chest pain, which is usually pleuritic, but there are cases with significant degrees of arterial occlusion with little or no symptoms.

In cor pulmonale, the predominant symptomatology is that of the underlying disease itself. In cases of right heart failure, signs such as: edema in the lower extremities, jugular engorgement, hepatomegaly (enlargement of the liver) and cyanosis may appear.

Diagnosis

Complementary tests in the case of pulmonary hypertension are usually not very specific. blood tests are usually normal and cardiac studies by electrocardiogram and echocardiogram show hypertrophy and overload of the right ventricle.

The diagnosis is based on the angiographic study after catheterization of the pulmonary circuit, after ruling out other respiratory, cardiovascular and systemic diseases as the cause of the clinical picture, but it must be taken into account that these are high-risk explorations and their indication should be individualized.

In PE, complementary tests are also nonspecific, being mostly useful to rule out other processes with similar symptoms (pneumonia, pneumothorax, myocardial infarction, among others). The diagnosis of pulmonary arterial occlusion is made with ventilation / perfusion scintigraphy. Together with the results of the chest X-ray, universal criteria for high, medium, and low probability of PE have been developed in order to avoid the use of arteriography, which is the definitive but high-risk diagnostic test. Its use is only reserved for doubtful cases or for situations of high urgency.

Treatment

The most effective treatment consists of treating the underlying disease, in some cases reducing pulmonary pressure by correcting the primary cause.

However, in cases of primary pulmonary hypertension, treatment is limited. In a natural way, the disease progressively worsens with an average life span from the appearance of the first symptoms of about 5 years, however, there are cases with evolutions greater than 20 years. Supportive measures consist of oxygen therapy in patients with hypoxemia and diuretics in cases of fluid overload.

Vasodilator treatment is useful in some cases but it is not possible to anticipate which patients will respond to treatment. Of particular note are intravenous epoprenostol (prostacyclin), intravenous adenosine, oral calcium antagonists, or inhaled nitric oxide. In patients who respond to these drugs, their symptoms improve and may even extend survival.

Anticoagulation is usually indicated in most patients with primary pulmonary hypertension, due to the increased risk of thrombosis and the limitation of physical activity. The last therapeutic resort is a lung transplant of one or both lungs, even with reduced heart function.