Increased Dead Space Ventilation as a Contributing Factor to Persistent Exercise Limitation in Patients with a Left Ventricular Assist Device.

Wernhart S; Balcer B; Rassaf T; Luedike P;

Journal of clinical medicine [J Clin Med] 2023 May 25; Vol. 12 (11).
Date of Electronic Publication: 2023 May 25.

(1) Background: The exercise capacity of patients with a left ventricular assist device (LVAD) remains limited despite mechanical support. Higher dead space ventilation (V D /V T ) may be a surrogate for right ventricular to pulmonary artery uncoupling (RV-PA) during cardiopulmonary exercise testing (CPET) to explain persistent exercise limitations.
(2) Methods: We investigated 197 patients with heart failure and reduced ejection fraction with ( n = 89) and without (HFrEF, n = 108) LVAD. As a primary outcome NTproBNP, CPET, and echocardiographic variables were analyzed for their potential to discriminate between HFrEF and LVAD. As a secondary outcome CPET variables were evaluated for a composite of hospitalization due to worsening heart failure and overall mortality over 22 months.
(3) Results: NTproBNP (OR 0.6315, 0.5037-0.7647) and RV function (OR 0.45, 0.34-0.56) discriminated between LVAD and HFrEF. The rise of endtidal CO 2 (OR 4.25, 1.31-15.81) and V D /V T (OR 1.23, 1.10-1.40) were higher in LVAD patients. Group (OR 2.01, 1.07-3.85), VE/VCO 2 (OR 1.04, 1.00-1.08), and ventilatory power (OR 0.74, 0.55-0.98) were best associated with rehospitalization and mortality.
(4) Conclusions: LVAD patients displayed higher V D /V T compared to HFrEF. Higher V D /V T as a surrogate for RV-PA uncoupling could be another marker of persistent exercise limitations in LVAD patients.