Pulmonary Capillary Recruitment Is Attenuated Post Left Ventricular Assist Device Implantation

Abstract

Intoduction There is limited knowledge of pulmonary physiology and pulmonary function following continuous flow-left ventricular assist device (CF-LVAD) implantation. Therefore, the present study investigated if CF-LVAD influenced the pulmonary circulation by assessing pulmonary capillary blood volume and alveolar- capillary conductance as well as pulmonary function in heart failure patients. Methods 17 patients with severe HF who were scheduled for CF-LVAD (Heart Mate II® or Heart Ware®) implantation participated in the study. They underwent pulmonary function testing (measures of lung volumes and flow rates) and more unique measures of pulmonary physiology using a rebreathe-technique that quantified the diffusing capacity of the lungs for carbon monoxide and nitric oxide (DLCO and DLNO, respectively) pre and 3 months post CF-LVAD implantation. Results After CF-LVAD, pulmonary function was not significantly changed (p>0.05). For lung diffusing capacity, DLCO was significantly reduced (p=0.04), however, alveolar volume (VA) was not changed (p=0.47). After DLCO was corrected by VA, DLCO/VA demonstrated a trend towards reduction (p=0.08). For the alveolar-capillary component, capillary blood volume (Vc) and alveolar membrane conductance (Dm) were significantly or trended towards a reduction (p<0.04, p=0.06, respectively). However, Dm/Vc was not altered (p=0.92). Conclusions Early post CF LVAD implantation, Vc is reduced likely as a result of pulmonary capillary de-recruitment which contributes to the fall in lung diffusing capacity. There is limited knowledge of pulmonary physiology and pulmonary function following continuous flow-left ventricular assist device (CF-LVAD) implantation. Therefore, the present study investigated if CF-LVAD influenced the pulmonary circulation by assessing pulmonary capillary blood volume and alveolar- capillary conductance as well as pulmonary function in heart failure patients. 17 patients with severe HF who were scheduled for CF-LVAD (Heart Mate II® or Heart Ware®) implantation participated in the study. They underwent pulmonary function testing (measures of lung volumes and flow rates) and more unique measures of pulmonary physiology using a rebreathe-technique that quantified the diffusing capacity of the lungs for carbon monoxide and nitric oxide (DLCO and DLNO, respectively) pre and 3 months post CF-LVAD implantation. After CF-LVAD, pulmonary function was not significantly changed (p>0.05). For lung diffusing capacity, DLCO was significantly reduced (p=0.04), however, alveolar volume (VA) was not changed (p=0.47). After DLCO was corrected by VA, DLCO/VA demonstrated a trend towards reduction (p=0.08). For the alveolar-capillary component, capillary blood volume (Vc) and alveolar membrane conductance (Dm) were significantly or trended towards a reduction (p<0.04, p=0.06, respectively). However, Dm/Vc was not altered (p=0.92). Early post CF LVAD implantation, Vc is reduced likely as a result of pulmonary capillary de-recruitment which contributes to the fall in lung diffusing capacity.