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Differentiation


Differentiating PH: it’s not all PAH


This articles provides an overview of the differentiation, diagnosis and treatment of PH, acknowledging the consensus reached at the Fifth World Symposium on Pulmonary Hypertension held in France in 2013


Harm Jan Bogaard MD PhD FAHA Anton Vonk Noordegraaf MD PhD FCCP Department of Pulmonary Medicine Institute for Cardiovascular Research VU University Medical Center Amsterdam, The Netherlands


While most doctors encounter patients with high pressure in the systemic circulation on a regular basis, they will much less frequently diagnose a patient with pulmonary hypertension (PH). The most serious form of this condition, pulmonary arterial hypertension (PAH), was not described until the 1950s.1


In the past two


decades, new, effective therapies have become available and early treatment of PAH patients has improved their survival.2–5 This chapter provides an overview of the diagnosis and treatment of PH, acknowledging the consensus reached at the Fifth World Symposium on Pulmonary Hypertension (WSPH), held in Nice in February 2013.6


8


The normal physiology of the pulmonary circulation is characterised by low vascular resistance and low pressure in the pulmonary arteries of around 12mmHg. PH is defined as mean pulmonary artery pressure higher than 25 mmHg. Symptoms of PH are a consequence of a compromised function of the right ventricle of the heart and primarily consist of a decreased exercise tolerance. Only in later stages of the disease, increased venous pressure results in ascites and ankle oedema. Other symptoms of patients with PH are fatigue, shortness of breath, chest pain and palpitations. Because most symptoms are non-specific and the disease is rare, a final diagnosis of PH is, on average, only made three years after the onset of symptoms.7


In most cases of PH, www.hospitalpharmacyeurope.com 5. Other


Table 1: Diagnostic classification of pulmonary hypertension (PH), Nice update8 Group


Examples 1. PAH


• Idiopathic • Hereditary


• Drug-induced (appetite suppressants; dasatinib, etc.) • Associated with congenital heart disease, systemic sclerosis, portopulmonary hypertension, HIV infection, etc


2. PH due to left heart failure and/ or valve disease


3. PH due to chronic hypoxic lung disease


4. CTEPH


• Systolic heart failure • Diastolic heart failure • Valve disease


• COPD


• Interstitial lung disease • Sleep apnoea


• Following an acute episode of venous thromboembolism (70% of all patients) • In 30% of cases, no history of acute venous thromboembolism


• Haematological disorders • Sarcoidosis • Gaucher’s disease


• Langerhans cell histiocytosis


Pulmonary arterial hypertension (PAH)-specific treatment consists of prostanoids, endothelin receptor antagonists, type 5 phosphodiesterase inhibitors and soluble guanylyl cyclase stimulators. COPD = chronic obstructive pulmonary disease; CTEPH = chronic thromboembolic PH.


the disease is associated with an underlying condition. Currently, more than 40 causes of PH have been recognised and these are subdivided into five groups (Table 1). In Nice, the existing classification of PH was largely kept unchanged.8


PH due to left heart disease The most common cause of PH is left heart failure, either with preserved or reduced ejection fraction (HFpEF or HFrEF, respectively). In this condition, an elevated left ventricular end-diastolic pressure is transmitted into the left atrium and pulmonary circulation. This passive increase in pressure is frequently compounded by functional (vasoconstriction) and structural (remodelling) changes in the pulmonary vascular bed, from arterioles to venules. Left heart failure can be associated with very severe increases in pulmonary artery


pressure, but there are no treatment options in addition to standard left heart failure therapy.9


When valve abnormalities are


present, surgical correction needs to be considered.


PH due to chronic lung diseases and/ or hypoxia


Most chronic lung diseases, including chronic obstructive pulmonary disease (COPD) and diffuse parenchymal lung diseases, not only affect the airways but also to some extent the pulmonary vasculature. PH in these conditions may follow a decrease in number of vessels or a decrease in vessel luminal surface, which can result from hypoxic vasoconstriction, vessel obstruction and vessel remodelling. In most instances, the increase in mean pulmonary artery pressure is relatively mild.10


High- altitude residence (>2500m above sea level)


Yes, when inoperable


No (with exceptions)


No No


Medical treatment


Yes


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