Abnormal Left Atrial Strain by CMR Is Associated With Left Heart Disease in Patients With Pulmonary Hypertension

Pulmonary hypertension (PH) is classified as precapillary, isolated postcapillary pulmonary hypertension (IpcPH), combined postcapillary and precapillary (CpcPH), or exercise PH. IpcPH associated with left heart disease can lead to pulmonary vascular remodeling and eventually CpcPH. Conversely, precapillary PH may be diagnosed in the presence of cardiovascular comorbidities, including left heart disease. Atrial functional impairment is a frequent finding in cardiopulmonary disease, reflecting both intrinsic atrial cardiomyopathy and congestion. Consequently, we sought to investigate this across the PH spectrum.

Patients referred to both right heart catheterization and cardiovascular magnetic resonance imaging were enrolled in this monocentric registry. Patients were classified by right heart catheterization according to current guideline recommendations. Cardiovascular magnetic resonance assessment included left/right ventricular and left atrial (LA)/right atrial volumes and deformation imaging.

The study population consisted of N=209 patients (n=55 normal, n=72 precapillary, n=27 CpcPH, n=15 IpcPH, n=34 exercise, and n=6 unclassified PH). N=126 patients underwent additional exercise stress right heart catheterization. Median LA reservoir function was lowest and similar in IpcPH (10.0%) and CpcPH (10.0%), which were significantly impaired compared with normal hemodynamics (30.8%, both P<0.001), precapillary (28.2%, both P<0.001), and exercise PH (26.9%, IpcPH: P=0.039, CpcPH: P=0.048). LA reservoir function and left ventricular global longitudinal strain showed good diagnostic performance to identify patients with left cardiac involvement evident at rest (pulmonary capillary wedge pressure ≥15 mm Hg; area under the curve, 0.81 versus 0.77; P=0.20), whereas LA reservoir function emerged superior for identification of exercise stress induced pulmonary capillary wedge pressure ≥25 mm Hg (area under the curve, 0.79 versus 0.70, P=0.039).

LA functional impairment is a sign of left heart involvement in patients with PH. Left atrial reservoir function emerged superior for the identification of left heart disease unmasked during exercise stress compared with left ventricular global longitudinal strain. Consequently, LA strain may become an innovative method to detect early-stage left heart disease in PH.