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Exercise gas exchange in continuous-flow left ventricular assist device recipients
Alessandro Mezzani1, Massimo Pistono1, Piergiuseppe Agostoni2
1Exercise Pathophysiology Laboratory, Cardiac Rehabilitation Division, Scientific Institute of Veruno IRCCS, Istituti Clinici Scientifici Maugeri Spa SB, Veruno (NO), Italy.
Plos One
|June 2, 2018
Summary
Continuous-flow left ventricular assist device (LVAD) recipients exhibit alveolar wasted ventilation during exercise, similar to advanced heart failure patients. This hypoperfusion is linked to right ventriculo-arterial coupling and effective circulating volume.
Area of Science:
- Cardiopulmonary exercise physiology
- Medical device technology
- Heart failure management
Background:
- Ventilation/perfusion (V/Q) matching during exercise is crucial for gas exchange efficiency.
- Systematic studies on V/Q matching in continuous-flow left ventricular assist device (LVAD) recipients are lacking.
- Understanding exercise limitations in LVAD patients is vital for optimizing therapy.
Purpose of the Study:
- To systematically investigate exercise ventilation/perfusion matching in LVAD recipients.
- To compare V/Q matching in LVAD patients with chronic heart failure (HFrEF) patients.
- To identify factors influencing gas exchange abnormalities in LVAD recipients.
Main Methods:
- Cardiopulmonary exercise testing with arterial blood gas analysis in 25 LVAD patients and 30 HFrEF patients.
- Echocardiography and venous blood sampling for renal function assessment.
- Calculation of arterial-end-tidal PCO2 difference (P(a-ET)CO2) and dead space-tidal volume ratio (VD/VT) as V/Q descriptors.
Main Results:
- LVAD recipients and matched HFrEF patients showed no significant rest-to-peak change in P(a-ET)CO2, indicating stable alveolar wasted ventilation.
- A significant decrease in P(a-ET)CO2 was observed in a control HFrEF group with better exercise capacity.
- Rest-to-peak changes in P(a-ET)CO2 correlated with VD/VT, and TAPSE/PASP and BUN/Cr ratio independently predicted peak P(a-ET)CO2.
Conclusions:
- LVAD exercise gas exchange is characterized by alveolar hypoperfusion, similar to advanced HFrEF.
- Right ventriculo-arterial coupling and circulating effective volume influence exercise gas exchange in LVAD patients.
- These findings highlight the importance of assessing V/Q matching and related hemodynamic factors in LVAD management.
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