Left ventricular volume and wall stress are linked to lung function impairment in COPD

Abstract

Background: Cardiovascular comorbidities are common in COPD, increasing morbidity and mortality. Underlying mechanisms are unclear. Aim: To study associations between lung function and left ventricular (LV) volume and wall stress. Methods: A subset of 641 patients from COSYCONET underwent evaluations including FEV1, FVC, effective airway resistance (Reff), intrathoracic gas volume (ITGV) and echocardiography (LV end-diastolic, end-systolic and stroke volume [LVEDV, LVESV, LVSV] and LV wall stress). Visit 1 was compared with Visit 3 (after 573±45 days), followed by cross-sectional multivariate regression analyses, then structural equation modelling (SEM) with latent variables ‘left heart’ and ‘lung’. Results: There were statistically significant declines from V1 to V3 in FEV1 and FEV1/FVC, and increases in Reff, ITGV and LV end-diastolic wall stress. Multivariate analysis revealed significant correlations of FEV1% pred with LVEDV and LVSV, Reff with LVSV, ITGV with LV mass and LV end-diastolic wall stress. The SEM fitted the data well at both visits with comparative fit indices of 0.978 and 0.962, respectively, and strong correlations between ‘lung’ and ‘left heart’ and between ‘left heart’ and LV diastolic and systolic wall stress. Conclusion: For the first time, we have shown a robust, repeatable relationship between lung function and LV wall stress in COPD, cross-sectionally and over 18 months. These findings support the hypothesis that the development of LV impairment in COPD could be initiated or promoted by mechanical factors exerted by the lung. Although the clinical implications of this finding are currently unclear, it would be sensible to monitor echocardiographic changes in COPD.