Left heart involvement in pulmonary hypertension translates to gradual left atrial functional impairment

Pulmonary hypertension (PH) is classified as pre-capillary, isolated post-capillary (IpcPH), combined post- and pre-capillary (CpcPH), or exercise PH. On the one hand, IpcPH associated with left heart disease may lead to pulmonary vascular remodelling and eventually to CpcPH. On the other hand, pre-capillary PH may be diagnosed in the presence of left heart failure. Left/right atrial (LA/RA) functional impairment is a frequent finding in cardio-pulmonary disease reflecting both intrinsic atrial impairment and congestion. Consequently, we sought to investigate this across the PH spectrum.

Patients referred to both right heart catheterisation (RHC) and cardiovascular magnetic resonance (CMR) imaging were enrolled in this monocentric registry. Patients were classified by RHC according to current guideline recommendations. CMR assessment included left ventricular (LV) volumes and LA/RA phasic deformation imaging.

The study population consisted of n=210 patients, n=123 underwent exercise-stress RHC (n=55 without PH, n=72 pre-capillary, n=26 CpcPH, n=17 IpcPH, n=34 exercise and n=6 unclassified PH). LA total strain (Es) was highest and similar in normal haemodynamics and pre-capillary PH (30.8% vs. 28.2%, p=0.358). A significant decrease was seen in exercise PH (26.9%, p=0.022) compared to normal haemodynamics. IpcPH (10.0%) and CpcPH (10.1%) showed lowest LA Es which was significantly impaired compared to normal haemodynamics, pre-capillary and exercise PH (<0.001-0.002). LA Es and global longitudinal strain (GLS) equally identified patients with left cardiac involvement evident at rest (pulmonary capillary wedge pressure (PCWP) ≥15mmHg) (AUC 0.82 vs 0.77, p=0.153) whilst LA Es emerged superior for identification of exercise-stress induced PCWP ≥25mmHg (AUC 0.79 vs 0.69, p=0.031).

Left atrial functional impairment is a sign of left heart involvement in PH patients and LA Es emerges superior for identification of exercise-stress induced elevated PCWP compared to GLS. This may imply LA deformation imaging as an innovative method to detect left cardiac disease across the PH spectrum.