Management
Management of PH should focus on treatment of the underlying condition and general supportive measures, with additional management strategies being considered by a specialist in pulmonary hypertension. Patients with PH in group 1, 4 and 5 should be referred to a specialist centre without delay.
Most cases of PH are due to underlying left heart disease (Group 2) or lung disease (Group 3), and management is often led by cardiologist and respiratory physicians respectively.
Treatment aims to prolong survival, improve functional class, improve 6MWT, improve right ventricular function and reduce/normalise BNP.
General Supportive Therapy
General supportive therapy has a role for improving patient’s symptoms and quality of life, although has limited impact on disease progression.
- Anticoagulation therapy – in PAH and CTEPH
- Diuretics (furosemide, spironolactone) – in patients with fluid overload symptoms of right heart failure
- Digoxin – in patients with concurrent arrhythmia (such as atrial fibrillation or atrial flutter)
- Oxygen therapy – in patients with hypoxaemia
- Avoid pregnancy – woman of childbearing age should be given progesterone-only contraception (to avoid prothrombotic effects of the combined pill) and termination is recommended in the event of pregnancy
- Annual influenza vaccine
- Encourage low level aerobic exercise, avoid high intensity exercise
Targeted Medical Therapy
Targeted medical therapy is commenced by specialist PH centres. Their aim is to improve exercise capacity and symptoms, haemodynamic parameters and patient quality of life. It is indicated in patients with PAH class II and above who have not responded to general supportive measures.
Some patients with IPAH may benefit from calcium channel blockade. To isolate this subgroup, patients with IPAH without right sided cardiac failure undergo vasodilator testing to identify those whose pulmonary arterial pressures fall following the administration of vasodilators. The minority of patients (10-15%) have a positive response to vasodilators (fall in mean pulmonary artery pressure of >20% with an increased or unchanged cardiac output during acute challenge) and can commence treatment on CCB’s. CCB’s are aimed at reducing pulmonary vascular resistance. Choice of CCB is dependent on the patient’s baseline heart rate. If heart rate is less than 100 beats per minute nifedipine or amlodipine would be first line, however if the patient’s heart rate is greater than 100 beats per minutes then diltiazem would be the preferred drug for its negatively chronotropic effect.
Most patients with PAH have a negative response to vasodilator testing. These patients should be considered for alternative targeted medical therapy, which consists of 4 drug classes shown in Table 3 below.
| Drug class | Mechanism of action | Example Drug (route) |
|---|---|---|
| Prostanoids | Prostacyclin analogues → effective vasodilators, inhibit platelet aggregation, inhibits vascular proliferation | Selexipag (oral)
Epoprostenol (intravenous infusion) Iloprost (nebulised) |
| Endothelin receptor antagonists | Inhibits endothelin-1 → prevents vasoconstriction and smooth muscle cell proliferation | Bosentan (oral)
Sitaxentan (oral) Ambrisentan (oral) |
| Phosphodiesterase-5 inhibitors | Enhances cellular effects of nitric oxide → increases sustained smooth muscle relaxation and thus pulmonary vasodilation | Sildenafil (oral) |
| Soluble guanylate cyclase stimulator | Riociguat (oral) |
Table 3: PAH targeted medical therapy drug classes
Treatment decision is dependent on risk stratification of patients into either low, intermediate or high risk. This risk stratification is based on clinical judgement and the following criteria defined in Table 4.
| Low risk (< 5%) | Intermediate risk (5 – 10%) | High risk (> 10%) | |
| Symptom progression | Absent | Slow | Rapid |
| Signs of heart failure | Absent | Absent | Present |
| WHO functional class | I or II | III | IV |
| 6-Minute-Walk-Distance | > 440 metres | 165 – 440 metres | < 165 metres |
| Cardiopulmonary exercise testing
Peak VO₂ (mL/min/kg) VE/VCO₂ slope |
Peak VO₂ > 15 (> 65% predicted)
VE/VCO₂ slope < 36 |
Peak VO₂ 11 – 15 (35% 65% predicted)
VE/VCO₂ slope 36 – 44 |
Peak VO₂ < 11 (< 35% predicted)
VE/VCO₂ slope ≥ 45 |
| B-type natriuretic peptide/N-terminal proBNP | BNP < 50 nanograms/mL
NT-proBNP < 300 nanograms/mL |
BNP 50 – 300 nanograms/mL
NT-proBNP 300 – 1400 nanograms/mL |
BNP > 300 nanograms/mL
NT-proBNP > 1400 nanograms/mL |
| Echocardiogram:
Pericardial effusion Right atrial area |
No pericardial effusion RA area < 18 | No/minimal pericardial effusion RA area 18 – 26 cm² | Pericardial effusion RA area > 26 cm² |
| Haemodynamic Parameters:
Right atrial pressures Cardiac Index Mixed venous oxygen saturations |
RAP < 8 mmHg
CI ≥ 2.5 l/minute /m² SvO₂ > 65% |
RAP 8 – 14 mmHg
CI 2.0 – 2.4 L/minute/m² SvO₂ 60 – 65% |
RAP > 14 mmHg
CI < 2.0 L/minute/m² SvO₂ <60% |
Table 4: PH risk stratification criteria
Low or intermediate risk patients can be commenced on an oral agent from one of the above classes or on multiple in the form of oral combination therapy. If the patient is unresponsive to oral combination therapy, they are then considered for parenteral prostanoids, such as epoprostenol, with the option of adding an endothelin receptor antagonist or phosphodiesterase-5 inhibitor or soluble guanylate cyclase stimulator.
Patients within the high-risk group should be immediately started on an intravenous epoprostenol, which can prolong survival. If treatment goals are not achieved, combination therapy with an endothelin receptor antagonist or phosphodiesterase-5 inhibitor is indicated.
Surgical Management
Patients’ refractory to targeted therapies with severe symptomatic PAH may be considered for transplantation. This includes a single or double lung transplant or a heart-lung transplant.
In Group 4 patients with CTEPH, pulmonary endarterectomy (PEA) surgery can be performed to remove old blood clots from the lungs. This is recommended alongside life-long anticoagulation and can potentially cure CTEPH with > 90% 5-year-survival.
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