To evaluate the effects of high intensity interval training (HIIT) on patients exercise capacity and health-related quality of life (HRQoL), after a heart transplant (HTx), in comparison to moderate intensity training.
All patients were provided with general advice on lifestyle changes and then randomized into a high intensity intervention training or moderate intensity (n=39), continuous training group (n=42).
81 heart transplant recipients.
The primary outcome was assessed as the change in VO2 peak from baseline to follow-up. Secondary outcomes included muscular capacity; chronotropic responses; right heart catheterization hemodynamics; lung function; cardiac dimension and function;; arteriovenous oxygen difference (a-v O2 diff); endothelial function; HRQoL;tolerability; safety; and exercise-related adverse events.
Mr John O'Callaghan, Centre for Evidence in Transplantation, The Royal College of Surgeons of England.
This is a good quality, multicentre RCT that is clearly reported. Both arms of the study received physical training sessions post-transplant, but the only difference was the intensity of the exercise. High intensity interval training initiated 11 weeks after heart transplant was safe. It showed a larger improvement in VO2 peak compared to moderate intensity training, although the treatment group started at a lower baseline on average. High intensity training also showed significantly larger increases in anaerobic threshold and muscular strength. There was no serious, exercise-related adverse event in either group. Adherence was monitored throughout, and across both groups was
81% completion of intended exercise sessions. The performance of unsupervised exercise would be a useful addition to the study.
There is no consensus on how, when, or at what intensity exercise should be performed after heart transplantation (HTx). We have recently shown that high-intensity interval training (HIT) is safe, well tolerated, and efficacious in the maintenance state after HTx, but studies have not investigated HIT effects in the de novo HTx state. We hypothesized that HIT could be introduced early after a HTx, and that it could lead to clinically meaningful increases in exercise capacity and health-related quality of life (HRQoL). METHODS
This multicenter, prospective, randomized, controlled trial included 81 patients, mean 11 weeks (range 7- 16) after a HTx. Patients were randomized, 1:1, to either nine months of HIT (4x4-min intervals at 85-95% of peak effort) or moderate intensity continuous training (MICT) (60-80% of peak effort). The primary outcome was the effect of HIT vs. MICT on the change in aerobic exercise capacity, assessed as the VO2peak
. Secondary outcomes included tolerability, safety, adverse events, isokinetic muscular strength, body composition, HRQoL, left ventricular function, hemodynamics, endothelial function, and biomarkers. RESULTS
From baseline to follow-up, 96% of patients completed the study. There were no serious exercise-related adverse events. The population comprised 73% men, and the mean (+/-SD) age was 49 (+/- 13) years. At the 1-y follow-up, the HIT group demonstrated greater improvements than those observed in the MICT group; the groups showed significantly different changes in the VO2peak
(mean difference between groups: 1.8 ml/kg/min), the anaerobic threshold (0.28 L/min), the peak expiratory flow (11%), and the extensor muscle exercise capacity (464 Joules). The 1.8 ml/kg/min difference was equal to approximately 0.5 metabolic equivalents, which is regarded as clinically meaningful and relevant. HRQoL was similar between the groups, based on results from Short Form-36 (version 2), the Hospital Anxiety and Depression scale, and a visual analogue scale. CONCLUSIONS
We demonstrated that HIT was a safe, efficient exercise method in de novo HTx recipients. HIT, compared to MICT, resulted in a clinically significantly greater change in exercise capacity, based on the VO2peak
values (25% vs. 15%), the anaerobic threshold, the peak expiratory flow, and muscular exercise capacity. CLINICAL TRIAL REGISTRATION
Unique Identifier NCT01796379.