Background: Left ventricular diastolic dysfunction (LVDD) in chronic thromboembolic pulmonary hypertension (CTEPH) is attributed to the effects of pulmonary hypertension on left ventricular function. LVDD is however prevalent in older populations and may exist independent of CTEPH, moreover CTEPH may mask LVDD by reducing LV filling.

Methods: Consecutive individuals undergoing pulmonary endarterectomy (PEA) for CTEPH between 2007 and 2018 were included (n = 1266). Left atrial pressure elevation was denoted by a pulmonary arterial wedge pressure (PAWP) > 15mmHg. Echocardiographic (n = 311) and cardiac MRI (n = 149) analysis was performed in a sub-cohort. PEA morbidity and mortality outcomes were assessed.

Results: LV filling was impaired in CTEPH with reduced E velocity and E/A reversal. There was an increase in LV filling with PEA on echocardiogram (left atrial area, E velocity, lateral/average E/e?, p < 0.001; all) and cardiac MR (left atrial volume and LV volumes, p < 0.001; all). 135 individuals had a PAWP > 15mmHg following PEA of which 60% had a normal PAWP pre-operatively. Left atrial dilation and increased LV mass were independent predictors of PAWP elevation. Common cardiovascular co-morbidities were more prevalent in those with post-operative LVDD. Evidence of LVDD was associated with lower haemodynamic and functional gains following PEA, a higher requirement for peri-operative non-invasive ventilation and impaired long-term survival.

Conclusions: LVDD in CTEPH is accentuated post-PEA and associated with increased morbidity and mortality outcomes. LVDD should be considered when assessing operative risk.