Association of Airflow Obstruction and Left Atrial Conduit Strain in Patients with Known or Suspected Coronary Artery Disease

PURPOSE: Airflow obstruction (AO) and coronary artery disease (CAD) share smoking as a risk factor. They may be associated with alterations in ventricular and atrial volumes and functions, and global coronary flow reserve (CFR), all of which can be assessed by cardiovascular MR (CMR). The purpose of this study was to evaluate the association between AO severity and CMR parameters in patients with known or suspected CAD. METHODS: Eighty patients with known or suspected CAD who underwent CMR, including cine, stress and rest perfusion, stress and rest coronary sinus flow measurements by phase-contrast cine, and late gadolinium enhancement; spirometry; and lung CT within 6 months were included in the study. Ventricular and atrial volumes and functions, and global CFR were evaluated by CMR. AO severity was evaluated by the ratio of the forced expiratory volume in the first second to the forced vital capacity (FEV1/FVC). Emphysema severity was determined by Goddard score. RESULTS: Median FEV1/FVC for all patients was 74.8%. Compared with patients with FEV1/FVC above the median, those with FEV1/FVC below the median had more impaired left atrial (LA) reservoir strain (P = 0.010), LA conduit strain (P = 0.012), left ventricular global longitudinal strain (P = 0.025), right atrial reservoir strain (P = 0.028), and Goddard score (P < 0.001). There was no significant difference in global CFR between the groups. Multiple linear regression analysis revealed LA conduit strain and Goddard score as independently associated with FEV1/FVC (β = 0.318, P = 0.001 and β = -0.422, P < 0.001, respectively). CONCLUSION: LA conduit function was independently associated with FEV1/FVC in patients with known or suspected CAD after adjusting for age, sex, smoking, and the CMR indices. This finding suggests that AO severity is associated primarily with impaired LA conduit function in patients with known or suspected CAD.