Left ventricular support adjustment to aortic valve opening with analysis of exercise capacity.

Daniele Camboni,York Zausig,Christof Schmid,Leopold Rupprecht,Bernhard Flörchinger,Patrycja Ganslmeier,Michael Hilker,Stephan Hirt,Tobias J Lange

doi:10.1186/1749-8090-9-93

Daniele Camboni, York Zausig + Show 7 more

Open Access

https://doi.org/10.1186/1749-8090-9-93

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Abstract

BackgroundLVAD speed adjustment according to a functioning aortic valve has hypothetic advantages but could lead to submaximal support. The consequences of an open aortic valve policy on exercise capacity and hemodynamics have not yet been investigated systematically.MethodsAmbulatory patients under LVAD support (INCOR®, Berlin Heart, mean support time 465 ± 257 days, average flow 4.0 ± 0.3 L/min) adjusted to maintain a near normal aortic valve function underwent maximal cardiopulmonary exercise testing (CPET) and right heart catheterization (RHC) at rest and during constant work rate exercise (20 Watt).ResultsAlthough patients (n = 8, mean age 45 ± 13 years) were in NYHA class 2, maximum work-load and peak oxygen uptake on CPET were markedly reduced with 69 ± 13 Watts (35% predicted) and 12 ± 2 mL/min/kg (38% predicted), respectively. All patients showed a typical cardiac limitation pattern and severe ventilatory inefficiency with a slope of ventilation to carbon dioxide output of 42 ± 12. On RHC, patients showed an exercise-induced increase of mean pulmonary artery pressure (from 16 ± 2.4 to 27 ± 2.8 mmHg, p < 0.001), pulmonary artery wedge pressure (from 9 ± 3.3 to 17 ± 5.3 mmHg, p = 0.01), and cardiac output (from 4.7 ± 0.5 to 6.2 ± 1.0 L/min, p = 0.008) with a corresponding slight increase of pulmonary vascular resistance (from 117 ± 35.4 to 125 ± 35.1 dyn*sec*cm−5, p = 0.58) and a decrease of mixed venous oxygen saturation (from 58 ± 6 to 32 ± 9%, p < 0.001).ConclusionAn open aortic valve strategy leads to impaired exercise capacity and hemodynamics, which is not reflected by NYHA-class. Unknown compensatory mechanisms can be suspected. Further studies comparing higher vs. lower support are needed for optimization of LVAD adjustment strategies.

Highlights

Left ventricular assist devices (LVAD) speed adjustment according to a functioning aortic valve has hypothetic advantages but could lead to submaximal support
An open aortic valve strategy leads to impaired exercise capacity and hemodynamics, which is not reflected by NYHA-class
The literature of cardiopulmonary exercise testing (CPET) and right heart catheterization (RHC) studies during exercise on support is limited [8,9], and the majority of these studies focused on the exercise capabilities of LVAD patients without emphasizing a normal aortic valve function

Summary

Introduction

LVAD speed adjustment according to a functioning aortic valve has hypothetic advantages but could lead to submaximal support. The consequences of an open aortic valve policy on exercise capacity and hemodynamics have not yet been investigated systematically. The literature of cardiopulmonary exercise testing (CPET) and right heart catheterization (RHC) studies during exercise on support is limited [8,9], and the majority of these studies focused on the exercise capabilities of LVAD patients without emphasizing a normal aortic valve function. No data exists describing exercise performance of patients with optimized pump speed with regard to a normal or near normal aortic valve physiology on long-term support (>6 months). We investigated the hemodynamic profile and exercise capacity in LVAD patients who received pump speed optimization following the mentioned approach

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