Associations between hemodynamic parameters at rest and exercise capacity in patients with implantable left ventricular assist devices

Abstract

Background: Hemodynamic parameters at rest are known to correlate poorly with peak oxygen uptake (VO2) in heart failure. However, we hypothesized that hemodynamic parameters at rest could predict exercise capacity in patients with left ventricular assist device (LVAD), because LVAD pump rotational speed does not respond during exercise. Therefore, we investigated the relationships between hemodynamic parameters at rest (measured with right heart catheterization) and exercise capacity (measured with cardiopulmonary exercise testing) in patients with implantable LVAD. Methods: We performed a retrospective medical record review of patients who received implantable LVAD at our institution from November 2013 to December 2017. Results: A total of 20 patients were enrolled in this study (15 males; mean age, 45.8 years; median duration of LVAD support, 356 days). The mean peak VO2 and cardiac index (CI) were 13.5 mL/kg/min and 2.6 L/min/m2, respectively. CI and hemoglobin level were significantly associated with peak VO2 (CI: r = 0.632, p = 0.003; hemoglobin: r = 0.520, p = 0.019). In addition, pulmonary capillary wedge pressure, right atrial pressure, and right ventricular stroke work index were also significantly associated with peak VO2. In multiple linear regression analysis, CI and hemoglobin level remained independent predictors of peak VO2 (CI: β = 0.559, p = 0.006; hemoglobin: β = 0.414, p = 0.049). Conclusions: CI at rest and hemoglobin level are associated with poor exercise capacity in patients with LVAD.

Relationship between spleen size and exercise tolerance in advanced heart failure patients with a left ventricular assist device

“…The reason for these findings may be related to the specificity of the study population, which was small in size and comprised a high proportion of males. RVSWI, which is an index of RV function, was strongly associated with peak VO 2 , which is consistent with previous studies [8,9]. One study reported that peak CO is best correlated with peak VO 2 in HF patients with LVADs [24].…”

“…However, despite the observed increase in spleen volume and the improvement in hemodynamics in patients with HF after LVAD implantation [6], another study reported no improvement in exercise tolerance in these patients during cardiac rehabilitiation [8]. Our group has previously shown that right heart catheter indices at rest correlate with exercise tolerance in LVAD patients [9]. As such, resting spleen volume reflects resting right heart catheter parameters, and therefore, its relationship to exercise tolerance is a valid subject of investigation.…”

Exercise physiology in left ventricular assist device patients: insights from hemodynamic simulations

“…Furthermore, as opposed to stable HF patients where pVO 2 s are clinically interpreted based on beta blockers, in LVAD patients treatment with beta blockers showed no clear trend of influencing pVO 2 s, nor did atrial fibrillation, noradrenaline levels or HF etiology (18,32,33,35). Contradictory results compared to the aforementioned studies were in regards to device type, chronotropic incompetence as well as determinants of right heart function (18,31,32,34,35).…”

“…In general, the following parameters have been reported to show associations with pVO 2 : age, total CO, flow through the aortic valve, peak arterial venous oxygen difference, chronotropic incompetence (HR reserve), hemoglobin levels, PCWP, NT-pro BNP, valve pathology or status, absolute LVAD parameters and timing of LVAD implant (18,(31)(32)(33)(34). Furthermore, as opposed to stable HF patients where pVO 2 s are clinically interpreted based on beta blockers, in LVAD patients treatment with beta blockers showed no clear trend of influencing pVO 2 s, nor did atrial fibrillation, noradrenaline levels or HF etiology (18,32,33,35).…”

“…Due to the still unclear picture of maximal and submaximal exercise tests, pre-and/or post-LVAD implantation, further studies have been conducted (34,39,40). Exercise test results and their potential for risk stratification would provide important clinical insights (17,21,41).…”