A 50-year-old woman known to have idiopathic pulmonary arterial hypertension (PAH) initially presented to us because of WHO class III-IV symptoms and repeated syncopal attacks. Urgent CT pulmonary angiogram had precluded acute pulmonary embolism. Echocardiography at that time demonstrated severe right heart enlargement with moderate systolic dysfunction, and pulmonary arterial systolic pressure (PASP) was 102mmHg (systemic blood pressure 120mmHg). Her right heart catheterization (RHC) showed mean pulmonary artery pressure (mPAP) 52mmHg, peak pulmonary arterial systolic pressure (PASP) 92mmHg, pulmonary capillary wedge pressure (PCWP) 10mmHg, pulmonary vascular resistance 10 Wood units and Qp: Qs=1:1, which were consistent with Group I pulmonary hypertension. She took regular dabigatran as anticoagulation, macitentan and sildenafil (both in maximum doses) as pulmonary vasodilatory agents for one year with modest improvement of symptoms. Her functional class is currently WHO class II-III and is now considering third PAH specific therapy. However, she is not keen to repeat RHC given past episode of groin haematoma. She received echocardiography to delineate the cause of her symptomatology.
The correct answer is Pulmonary arterial systolic pressure (PASP)
Right ventricular (RV) systolic function is one of the most important parameters in assessing PAH prognosis. PAH patients would not succumb because of high pulmonary pressure but rather die of progressive right ventricular failure. If there is evidence of persistent RV systolic dysfunction from echocardiography, further optimization of drug therapy should be considered. Small left ventricular (LV) size or impaired LV relaxation pattern is a poor prognostic sign of PAH because it reflects a small LV being compressed by RV in most cardiac cycles. Pulmonary artery systolic pressure (PASP) has long been an “important” echocardiographic parameter from a non-cardiologist perspective. However, the decrease in PASP in follow-up does not necessarily mean a better prognosis as it may also reduce in patients with significant RV failure. Thus, PASP confers little in the up or down titration of PAH specific therapy. Right arterial pressure (a surrogate marker of central venous pressure) and presence of pericardial effusion (as a result of systemic venous hypertension) are parameters associated with worse outcomes as suggested by the ESC/ERS guidelines and REVEAL registry, respectively.
By Dr Kevin Kam, Cardiologist, Prince of Wales Hospital, Hong Kong SAR, China
A 48-year-old woman with systemic sclerosis (SSc) reports a mild reduction in exercise capacity, but she can still walk 500 meters on the flat without any difficulties. She has a positive anti-centromere antibody, and her SSc is complicated by Raynaud’s, reflux and mild skin disease. Her lung function shows FEV1 92% predicted, FVC 90% predicted, TLC 90% predicted, and DLCO 62% predicted. Her HRCT scan does not show any interstitial lung disease. An echocardiogram was unable to estimate the systolic pulmonary artery pressure due to an insufficient tricuspid regurgitation jet. Right ventricle size and systolic function were normal. The right atrial area was slightly increased (19cm2).
The correct answer is Chest CT
Group 1 pulmonary artery hypertension (PAH) complicates 10-12 % of patients with SSc. However, it is important to note that in a patient with SSc, pulmonary hypertension can be due to left heart disease (Group 2), lung disease (Group 3) and thromboembolic disease (Group 4). Guidelines recommend routine screening for PAH in patients with SSc since early treatment is associated with better outcomes. A multimodal screening algorithm increases the sensitivity of diagnosing PAH. Echocardiography can miss early PAH, and clinicians should have a low threshold to refer for right heart catheter if there are other features suggestive of PAH such as elevated NT-pro BNP and high FVC/DLCO ratio. A right heart catheterisation is the gold standard for haemodynamic diagnosis of PAH.
By Prof Edmund Lau, Clinical Associate Professor, University of Sydney, Australia