WHAT IS PH? : CLINICAL PRESENTATION

DEFINITION AND CLASSIFICATION / PATHOPHYSIOLOGY / EPIDEMIOLOGY / CLINICAL PRESENTATION / MANAGEMENT / NATURAL HISTORY

Patients with PAH are often asymptomatic in the early stages and it is only as the condition becomes advanced and exercise tolerance limited that they present to medical attention. Initial symptoms can be non-specific and a high proportion of cases are misdiagnosed at first presentation. There can be a delay of several years between first onset of symptoms and final diagnosis and this delay is not falling over the years (see table below).

	Delay Between First Symptoms and Diagnosis (yrs)	Proportion of Patients in Functional Class III ? IV At Presentation (%)
American Registry 1987 (1)	2.03	71
French Registry 2006 (2)	2.25	75

The American prospective study (1) identified the common initial symptoms of the condition and these are summarised in the table below.

Initial Symptoms	Patients (%)
Dyspnea	60%
Fatigue	19%
Syncope or near syncope	13%
Chest pain	7%
Palpitations	5%
Leg oedema	3%

The signs of pulmonary hypertension are those of right heart strain and right heart failure and include:

a left parasternal heave
loud second heart sound (P2)
widening of the physiological splitting of P2
pansystolic murmur of tricuspid regurgitation (TR) at the left sternal edge
early diastolic murmur of pulmonary regurgitation
right venricular third heart sound
elevated JVP
hepatomegaly
peripheral oedema
ascites

The lungs are usually clear with no pleural effusions.

The CXR is abnormal in 94% of cases (prominence of the main pulmonary artery, enlarged hilar vessels, decreased peripheral vessels)1. The ECG shows right axis deviation in 79%, right ventricular hypertrophy in 87% and right ventricular strain in 74%1. Arrhythmias are rarely seen on the ECG.

Transthoracic cardiac echo is the best non-invasive method for establishing the likelihood of pulmonary hypertension. The peak velocity, v, of the the TR jet can be used to estimate the right ventricular systolic pressure (RVSP) using the formula

RVSP = 4.v2 + RAP

where RAP is the right atrial pressure (~5-10mmHg in the normal subject). In most cases pulmonary artery systolic pressure (sPAP) is equivalent to RVSP and mean pulmonary artery pressure is approximately 0.63 x sPAP. Whilst cardiac echo is a very useful tool it can only estimate PA pressure in the presence of a TR jet (~74% of subjects). Additionally the correlation between pressures at cardiac echo and cardiac catheterisation is good (0.57-0.93) but not perfect and the actual value must be confirmed invasively.

Further investigation of the patient with pulmonary hypertension is therefore best done at a specialist centre. It involves confirmation of the presence of pulmonary hypertension by right heart catheterization, investigation to identify the cause of the pulmonary hypertension and assessment of the severity of the condition in that subject. The most up to date description of the process is given in the European Society of Cardiology Guidelines (3).

(1) Rich S et al. Primary pulmonary hypertension. A national prospective study. Ann Intern Med 1987; 107:216-223.

(2) Humbert M et al. Pulmonary arterial hypertension in France. Results from a national registry. AJRCCM 2006; 173: 1023-30.

(3) Guidelines on diagnosis and treatment of pulmonary arterial hypertension. EHJ 2004; 25:2243-2278.