September 23, 2022

PAH affects regarding 1% of the world’s population, up to 10% of people over 65 years old. It is a severe pathology if it is not properly supported, which can lead to right heart failure.

Studies have shown that even moderately elevated pulmonary arterial pressure (PAP) or pulmonary vascular resistance (PVR) is associated with increased mortality. They had thus led to a modification of the hemodynamic definition. The average PAP threshold was lowered from 25 to 20 mmHg. “However, if the reductions in the thresholds of the average PAP and the PVR are clinically relevant, they do not yet translate into therapeutic recommendations. Indeed, the effectiveness of treatments remains poorly known for PAP between 21 and 24 mmHg or PVR between 2 and 3 WU. (Wood Unit, corresponding to a pressure difference of 1 mm Hg for a flow rate of 1 ml/s) », notes Pr Marion Delcroix (Belgium). For these limit values, treatment will not be initiated but patients will be closely monitored.

Often delayed treatment

Divided into five main groups according to its etiology, PAH exists as a distinct pulmonary vascular disease: distinct idiopathic (hereditary, toxic and associated with connective tissue disease), related to left heart disease, associated with chronic lung disease, of uncertain cause or multifactorial (linked to hematological, pulmonary, metabolic pathologies, etc.), or even HTAPEC.

The symptomatology is not specific, with generally progressive dyspnea and a decrease in exercise capacity. In addition, chronic fatigue, chest pain, palpitations, syncope on exertion, water retention in case of impaired right heart function, even hemoptysis are sometimes observed. ” Thus, the diagnosis of PAH and its appropriate management generally suffer from a considerable delay, insists Prof. Stephan Rosenkranz (Germany). We don’t think regarding it because these patients are young, often women first in good health, or if they are older, because the symptomatology is related to arterial hypertension, obesity or other cardiorespiratory pathologies”.

The diagnostic approach was simplified into three stages: suspicion of PAH by primary care physicians, diagnostic probability evoked by ultrasound and elimination of other cardiorespiratory causes of dyspnoea, then confirmation by right heart catheterization in expert centres.

Increased monitoring following pulmonary embolism

To shorten diagnostic delays, screening for PAH is offered in patients with scleroderma or at risk of hereditary PAH, as well as in the general population in the event of unexplained dyspnea or following a pulmonary embolism (PE). In patients undergoing PE, it is now recommended to look for signs suggestive of PAH on thoracic CT angiography and echocardiography. These patients will be followed systematically following PE to verify the absence of PAH, as already recommended by the recommendations on the diagnosis and management of acute PE. The therapeutic choice depends on the comorbidities and the stage of the disease (low, intermediate-low, intermediate-high or high risk).

In CAPH, treatment depends on the level of arterial obstruction. Pulmonary endarterectomy is preferred if patients are eligible. Balloon pulmonary angioplasty is indicated in certain subjects refused for surgery, or presenting with distal lesions or persistent PAH following the operation. Other cases will benefit from medical treatment, particularly in cases of microvasculopathy. Finally, exercise training is an integral part of the management of PAH.

(1) Humbert M, et al. 2022 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension. Eur Heart J 2022 Aug 26;ehac237; Eur Respir J. 2022 Aug 30;2200879