From the Guidelines
Pulmonary hypertension is a serious condition characterized by abnormally high blood pressure in the arteries of the lungs, diagnosed when the mean pulmonary artery pressure exceeds 20 mmHg at rest, as recently redefined in 2018 1. This condition occurs when the small blood vessels that supply the lungs narrow, become blocked, or are damaged, forcing the heart to work harder to pump blood through them. Normal pulmonary artery pressure at rest is between 8-20 mmHg. The condition is classified into five groups based on causes:
- Pulmonary arterial hypertension
- Left heart disease
- Lung disease
- Chronic blood clots
- Miscellaneous causes. Symptoms typically develop gradually and include shortness of breath during routine activity, fatigue, chest pain, racing heartbeat, and swelling in the ankles and legs. Treatment depends on the underlying cause but may include medications such as vasodilators, endothelin receptor antagonists, phosphodiesterase inhibitors, or prostacyclins, as recommended by recent guidelines 1. In severe cases, oxygen therapy or even lung transplantation may be necessary. Early diagnosis is crucial as the condition can lead to right heart failure if left untreated, as the right ventricle becomes enlarged and weakened from pumping against increased resistance, highlighting the importance of accurate and timely diagnosis, as emphasized in recent studies 1. It is essential to note that the diagnosis and treatment of pulmonary hypertension have evolved over the years, with updates in clinical classification and management guidelines, as reflected in the most recent studies 1.
From the Research
Definition of Pulmonary Hypertension
Pulmonary hypertension is a condition characterized by elevated pressures within the pulmonary arteries, which can lead to adverse vascular remodeling, obstruction, stiffening, and vasoconstriction of the pulmonary vasculature 2. This condition can be defined as a syndrome considering its clinical and pathophysiological manifestations, and it is perpetually fatal unless a tentative therapy is instituted 3.
Types of Pulmonary Hypertension
There are five main groups of pulmonary hypertension, all defined by a mean pulmonary artery pressure of >20 mmHg:
- Pulmonary arterial hypertension (rare)
- Pulmonary hypertension associated with left-sided heart disease (very common)
- Pulmonary hypertension associated with lung disease (common)
- Pulmonary hypertension associated with pulmonary artery obstructions, usually related to thromboembolic disease (rare)
- Pulmonary hypertension with unclear and/or multifactorial mechanisms (rare) 2
Pathophysiology and Clinical Characteristics
Pulmonary arterial hypertension (PAH) is a rare and progressive disease characterized by remodeling of the pulmonary arteries and progressive narrowing of the pulmonary vasculature, leading to a progressive increase in pulmonary vascular resistance and pulmonary arterial pressure 4. The pathophysiology of PAH involves endothelial dysfunction, vascular remodeling, and obstruction of small pulmonary arteries, resulting in increased pulmonary vascular resistance and pulmonary pressures 5. The clinical characteristics of PAH include reduced cardiac output, right heart failure, and ultimately death 5.
Diagnosis and Treatment
A correct diagnosis of PAH requires a complete work-up, including right heart catheterization performed in a specialized center 4. The treatment of PAH targets the three specific pathways of endothelial dysfunction that characterize the disease: the endothelin, nitric oxide, and prostacyclin pathways 4. Current treatments for PAH include medications such as iloprost, bosentan, and sildenafil, which have been shown to improve symptoms, exercise tolerance, and quality of life 6, 3. In severe cases, lung transplantation may be indicated 4.
Key Features and Symptoms
Key features of pulmonary hypertension include:
- Elevated pressures within the pulmonary arteries
- Adverse vascular remodeling, obstruction, stiffening, and vasoconstriction of the pulmonary vasculature
- Reduced cardiac output, right heart failure, and ultimately death
- Symptoms such as dyspnea, particularly in older individuals 2
- Exercise intolerance and fatigue
- Chest pain and palpitations
Prognosis and Management
The prognosis of pulmonary hypertension depends on the underlying cause and severity of the disease. With proper management, including medication and lifestyle modifications, it is possible to improve symptoms, slow disease progression, and increase survival rates 6, 3. However, there are still major gaps in basic, clinical, and translational knowledge, and further research is needed to better characterize, detect, and effectively treat all forms of pulmonary hypertension 2.