QuaLVAD Instrument: A New Measure of Quality of Life in Patients with a Left Ventricular Assist Device (LVAD)

Abstract

Background Although the use of LVADs in treating patients with advanced heart failure is growing, no current tool exists that can reliably assess health-related quality of life (HRQL) in this population. The QuaLVAD instrument has been designed to address this need. It incorporates important elements of LVAD-related care such as LVAD-specific complications, routine care of the device and other related clinical, personal and social factors. Methods The QuaLVAD instrument was designed after literature search, expert consultation, and patient discussion. It currently includes a 70-item instrument with scores ranging from 0-100 wherein a higher score signifies better HRQL. We assessed its performance by enrolling 24 patients and co-administered it with the Kansas City Cardiomyopathy Questionnaire (KCCQ) and visual analog scale (VAS) to stable patients implanted with a LVAD. Cronbach's alpha was calculated to measure the internal consistency of the instrument. Spearman correlation coefficients (ρ) and Wilcoxon rank-sum test helped assess for various associations of the QuaLVAD scores. Results The 24 subjects included had a mean age and BMI of 60.0 ± 13.2 years and 32.3 ± 18.2 kg/m2 respectively. The Cronbach's alpha for the entire instrument was 0.95 and >0.75 for all its six domains. Other summary statistics and the Cronbach's alpha for each domain are shown in Table 1. Amongst patient characteristics, the QuaLVAD overall score had the greatest correlation (ρ = -0.60) with the total number of comorbidities and a significant association with outpatient status of the subject (p-value = 0.05). A moderate negative correlation (ρ = -0.37) was observed with the New York Heart Association (NYHA) class. Convergent validity was established with strong correlation scores with the KCCQ and VAS (ρ of 0.84 and 0.67 respectively for overall scores; p-value ≤ 0.001). Subject feedback indicated that 52% considered the QuaLVAD instrument as more relevant in assessing their LVAD-related quality of life than any previously filled questionnaires. Conclusion Our results have demonstrated promising early insights into the internal consistency and validity of the QuaLVAD instrument. To further refine the instrument, we shall focus on item reduction, testing responsiveness to change in HRQL and more widespread application of this novel instrument.