Clinical features and determinants of VO_2peakinde novoheart transplant recipients

Abstract

AIMTo study exercise capacity and determinants of early peak oxygen consumption (VO2peak) in a cohort of de novo heart transplant (HTx) recipients.METHODSTo determine possible central (chronotropic responses, cardiopulmonary and hemodynamic function) and peripheral factors (muscular exercise capacity and body composition) predictive of VO2peak, a number of different measurements and tests were performed, as follows: Cardiopulmonary exercise testing (CPET) was performed mean 11 wk after surgery in 81 HTx recipients > 18 years and was measured with breath by breath gas exchange on a treadmill or bicycle ergometer. Metabolic/respiratory measures include VO2peak and VE/VCO2 slope. Additional measures included muscle strength testing, bioelectrical impedance analysis, echocardiography, blood sampling and health-related quality of life. Based on the VO2peak (mL/kg per minute) median value, the study population was divided into two groups defined as a low-capacity group and a high-capacity group. Potential predictors were analyzed using multiple regression analysis with VO2peak (L/min) as the dependent variable.RESULTSThe mean ± standard deviation (SD) age of the total study population was 49 ± 13 years, and 73% were men. This de novo HTx cohort demonstrated a median VO2peak level of 19.4 mL/kg per min at 11 ± 1.8 wk post-HTx. As compared with the high-capacity group, the low-capacity group exercised for a shorter time, had lower maximal ventilation, O2 pulse, peak heart rate and heart rate reserve, while the VE/VCO2 slope was higher. The low-capacity group had less muscle strength and muscular exercise capacity in comparison with the high-capacity group. In order of importance, O2 pulse, heart rate reserve, muscular exercise capacity, body mass index, gender and age accounted for 84% of the variance in VO2peak (L/min). There were no minor or major serious adverse events during the CPET.CONCLUSIONAlthough there is great individual variance among de novo HTx recipients, early VO2peak measures appear to be influenced by both central and peripheral factors.

Effect of High-Intensity Interval Training in De Novo Heart Transplant Recipients in Scandinavia

“…For example, in the first months after a HTx, both central factors (i.e., stroke volume and chronotropic responses) and peripheral factors seem to be predictive of VO2peak; however, later on, peripheral factors (i.e., muscular strength and function) are the dominant predictive factors. 7,[27][28][29] Although, in the early phase after HTx, central factors might be the leading cause of reduced VO2peak, de novo HTx recipients are also frequently physically deconditioned, with low muscular capacity, due to their heart failure history. This state is likely to contribute additionally to a reduced VO2peak.…”

An Update on the Role of Cardiorespiratory Fitness, Structured Exercise and Lifestyle Physical Activity in Preventing Cardiovascular Disease and Health Risk

“…12 documented beneficial health effects of CR in all patients, participation rates remain discouragingly low [66][67][68][69] . Members of the Million Hearts Cardiac Rehabilitation Collaborative have recently outlined effective strategies (automated referrals and strong physician endorsement) that clinicians can take to increase participation rates from ~20% -70% by the year 2022 70 .…”

Long-term effects of high-intensity training vs moderate intensity training in heart transplant recipients: A 3-year follow-up study of the randomized-controlled HITTS study

“…Body composition was determined prior to the exercise testing using bioelectrical impedance analysis with Tanita InnerscanV model BC‐545N (Tanita, Arlington, Heights, IL) 14,18 …”

“…Participants underwent a CPET, using a breath-by-breath method, on either a treadmill (Jaeger Masterscreen; Carefusion; Hoechberg, Germany) or on a bicycle (Schiller Cardiovit CS-200 Excellence, Baar, F I G U R E 2 Enrollment in the HITTS study [Color figure can be viewed at wileyonlinelibrary.com] Switzerland), as described previously. 8,13,14 The treadmill test-protocol was a ramp protocol with a constant speed and a gradually increasing inclination (2% every 2 minutes). 15 Pulmonary function was assessed using spirometry prior to the CPET.…”