Determinants of peak VO2 in heart transplant recipients

Abstract

ObjectiveTo establish the determinants of the peak VO2 in heart transplant recipients.MethodsPatient's assessment was performed in two consecutive days. In the first day, patients performed the heart rate variability assessment followed by a cardiopulmonary exercise test. In the second day, patients performed a resting echocardiography. Heart transplant recipients were eligible if they were in a stable condition and without any evidence of tissue rejection diagnosed by endomyocardial biopsy. Patients with pacemaker, noncardiovascular functional limitations such as osteoarthritis and chronic obstructive pulmonary disease were excluded from this study.ResultsSixty patients (68% male, 48 years and 64 months following heart transplantation) were assessed. Multivariate analysis selected the following variables: receptor's gender (P =0.001), receptor age (P =0.049), receptor Body Mass Index (P =0.005), heart rate reserve (P <0.0001), left atrium diameter (P =0.016). Multivariate analysis showed r=0.77 and r2=0.6 with P <0.001. Equation: peakVO2 =32.851 - 3.708 (receptor gender) - 0.067 (receptor age) - 0.318 (receptor BMI) + 0.145 (heart rate reserve) - 0.111 (left atrium diameter).ConclusionThe determinants of the peak VO2 in heart transplant recipients were: receptor sex, age, Body Mass Index, heart rate reserve and left atrium diameter. Heart rate reserve was the unique variable positively associated with peak VO2 . This data suggest the importance of the sympathetic reinnervation in peak VO2 in heart transplant recipients.

Clinical and Rehabilitative Predictors of Peak Oxygen Uptake Following Cardiac Transplantation

“…Previous studies have investigated demographic and clinical determinants of VO 2peak in various populations [10,11,12,13,14,15,16,17,18]. For example, the predictive influence of age, sex, and body mass index (BMI) on VO 2peak has been shown in healthy populations [16,17].…”

“…For example, the predictive influence of age, sex, and body mass index (BMI) on VO 2peak has been shown in healthy populations [16,17]. In HTx patients, these variables have also been shown to be prominent predictors of post-HTx VO 2peak along with chronotropic reserve, donor age, and time from HTx [11,13,14,18]. However, a limitation of these previous studies is the small sample sizes used ( n = 60–95) [11,13,14,18].…”

“…In HTx patients, these variables have also been shown to be prominent predictors of post-HTx VO 2peak along with chronotropic reserve, donor age, and time from HTx [11,13,14,18]. However, a limitation of these previous studies is the small sample sizes used ( n = 60–95) [11,13,14,18]. In addition, recent work has indicated that participation in cardiac rehabilitation (CR) in HTx postoperative care has been shown to be related to improvements in VO 2peak [15,19,20]; however, it is unclear if CR participation is predictive of a greater VO 2peak following HTx.…”

High-Intensity Interval Training in Heart Transplant Recipients: A Systematic Review with Meta-Analysis

“…Cardiac denervation causes cardiorespiratory (maximum oxygen uptake - VO 2 max) and hemodynamic (heart rate - HR, cardiac output - CO and blood pressure - BP) controls to depend initially on the Frank-Starling mechanism (the law states that preload depends on venous return) and, later, on the concentrations of circulating catecholamines and ejection fraction, because of the lack of sympathetic and parasympathetic stimulation and baroreflex. 5 - 7 Therefore, transplant recipients have a lower VO 2 max (70-80% of the value predicted for age as compared to healthy individuals), 8 high levels of HR, BP and vascular resistance at rest. However, physical exercise causes depressed increase in HR and BP, accompanied by an increase in vascular resistance.…”

Efeito agudo do exercício físico em piscina aquecida versus em solo sobre a pressão arterial e variabilidade da frequência cardíaca em indivíduos transplantados cardíacos

“…A denervação cardíaca parcial (técnica clássica) ou completa (técnica bicaval) faz com que o controle da frequência cardíaca, volume sistólico e, consequentemente, do débito cardíaco seja dependente do mecanismo de Frankling-Starling e concentrações plasmáticas de catecolaminas 14,15 . Apesar de haver evidências de reinervação cardíaca pós-transplante 15,16 , o grau em que ela ocorre demonstra grande variação entre os estudos 15 , e parece ser mais prevalente para fibras simpáticas que parassimpáticas 16 . Com isso, indivíduos com TX apresentam elevada FC de repouso, atraso no aumento da FC em resposta ao exercício físico, menores níveis de FC no esforço máximo, e lenta redução da FC pós-exercício quando comparados com indivíduos saudáveis 15,17,18 .…”