The right ventricle after endarterectomy and after angioplasty

Design

Prospective multicentre cohort study with cardiac MRI, right heart catheterisation, exercise testing and biomarkers at baseline and six months

Population

93 patients with chronic thromboembolic pulmonary hypertension in the Netherlands and Denmark: 50 pulmonary endarterectomy, 43 balloon pulmonary angioplasty

Primary outcome

Right ventricular reverse remodelling on cardiac MRI, with haemodynamic and functional response

Effect

Both improved afterload, function and exercise capacity (all p<0.05). Endarterectomy gave larger haemodynamic improvement (p-interaction 0.001 or less) and lower follow-up indexed right ventricular volumes: end-diastolic 76.2 vs 92.2 mL/m² (p<0.001), end-systolic 39.0 vs 49.0 mL/m² (p=0.014)

Balloon pulmonary angioplasty has become an established alternative to pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension, principally for patients whose disease is not surgically accessible. How the right ventricle recovers after each has not been compared directly with imaging.

Ninety-three patients from the Netherlands and Denmark — 50 endarterectomy, 43 angioplasty — had cardiac MRI, right heart catheterisation, exercise testing and biomarkers at baseline and six months, with a subgroup followed to 18 months. Both interventions improved right ventricular afterload, function and exercise capacity. Endarterectomy produced larger haemodynamic gains in mean pulmonary artery pressure and pulmonary vascular resistance, and correspondingly more reverse remodelling: indexed right ventricular end-diastolic volume at follow-up was 76.2 versus 92.2 mL/m², and end-systolic volume 39.0 versus 49.0 mL/m².

The comparison is not a fair fight and the authors do not pretend otherwise. Angioplasty patients were six years older, took more pulmonary hypertension medication, and started with a lower right ventricular mass index — differences that reflect why they were not operated on. The more interesting observation is the one the authors highlight: the sensitivity of the ventricle to unloading looked broadly similar across treatments. The right ventricle responds to having its afterload reduced, and endarterectomy simply reduces it more.

• Both procedures produced significant reverse remodelling; this is not a negative result for angioplasty
• The groups were not randomised and differed by age, medication and baseline right ventricular mass
• Larger haemodynamic improvement after endarterectomy tracked with larger volume reduction
• Continue assessing operability at an expert centre; nothing here changes patient selection
• The authors call for randomised trials, which do not yet exist

Why it matters

It shows the right ventricle recovers in proportion to how much afterload is removed, whichever route removes it.

Don't overread it

This was not randomised, and angioplasty patients were older with more advanced medical therapy — the groups differ for the reasons they received different treatments.

The statistics, in plain English

This is a comparison between two groups selected for different treatments on clinical grounds, so any difference in outcome partly reflects why they were selected. Follow-up volumes of 76.2 against 92.2 mL/m² differ clearly, but the endarterectomy group also started from a different place. The finding that responsiveness to unloading was similar across groups is the one least vulnerable to that selection, because it compares the relationship between afterload change and remodelling rather than the absolute outcome.

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