Introduction: Patient health status (PHS) and peak oxygen uptake (V.O2) are important predictors of clinical outcomes in individuals with heart failure. Preliminary studies of individuals with left ventricular assist devices (LVADs) show improvements in both PHS and peak V.O2. However, the relationship between peak V.O2 and PHS in this population is not well described. Likewise, data regarding muscular strength are also lacking in this population. We sought to describe the association between peak V.O2, muscular strength, and PHS in patients with continuous-flow LVADs.
Methods: Subjects (n = 26; 7 women) completed a symptom-limited graded exercise test within an average of 82 days (range, 33-167 days) of LVAD implant. In addition, subjects underwent a 6-Minute Walk Test and an isokinetic knee extension strength test and completed the Kansas City Cardiomyopathy Questionnaire (KCCQ). Spearman correlation coefficients were performed, adjusting for body weight and gender, to examine relationships between variables.
Results: Muscular strength, as measured by peak torque, and peak V.O2 were both moderately associated with the KCCQ (r = 0.58, P = .006; r = 0.51, P = .019). A subanalysis revealed that muscular strength and peak V.O2 were related to different domains within the KCCQ.
Conclusions: Leg muscle strength and peak V.O2 appear to be important factors related to PHS in patients with continuous-flow LVADs. This is likely partially a result of deconditioning due to recent hospitalization, as well as persistent heart failure-related peripheral maladaptations in skeletal muscle. Incorporating both a cardiovascular as well as strength training program before and after LVAD implant surgery may be beneficial.