ABC | Volume 110, Nº2, February 2018

Review Article High-Intensity Interval Training in Heart Transplant Recipients: A Systematic Review with Meta-Analysis Raphael José Perrier-Melo, 1 Fernando Augusto Marinho dos Santos Figueira, 2 Guilherme Veiga Guimarães, 3 Manoel da Cunha Costa 4 Universidade de Pernambuco (UPE); 1 Instituto de Medicina Integral Professor Fernando Figueira, 2 Recife, PE; Universidade de São Paulo, 3 São Paulo, SP; Universidade de Pernambuco (UPE), 4 Recife, PE – Brazil Keywords Exercise; Heart Failure/physiopathology; Life Style; Cardiac Rehabilitation; Meta-Analysis as Topic. Mailing Address: Raphael José Perrier-Melo • Escola Superior de Educação Física Rua Arnóbio Marques, 310, Recife, PE – Brazil E-mail: perrierprof@gmail.com , rperrier2@gmail.com Manuscript received May 29, 2017, revised manuscript August 11, 2017, accepted September 14, 2017 DOI: 10.5935/abc.20180017 Abstract Heart transplantation (HTx) is considered an efficient and gold‑standard procedure for patients with end-stage heart failure. After surgery, patients have lower aerobic power (VO 2 max) and compensatory hemodynamic responses. The aim of the present study was to assess through a systematic review with meta-analysis whether high-intensity interval training (HIIT) can provide benefits for those parameters. This is a systematic review with meta-analysis, which searched the databases and data portals PubMed, Web of Science, Scopus, Science Direct and Wiley until December 2016 (pairs). The following terms and descriptors were used: “ heart recipient ” OR “ heart transplant recipient ” OR ” heart transplant ” OR “ cardiac transplant ” OR “ heart graft ”. Descriptors via DeCS and Mesh were: “ heart transplantation ’’ OR “ cardiac transplantation ”. The words used in combination (AND) were: “ exercise training ” OR “ interval training ” OR “ high intensity interval training ” OR “ high intensity training ” OR “ anaerobic training ” OR “ intermittent training ” OR “ sprint training ”. The initial search identified 1064 studies. Then, only those studies assessing the influence of HIIT on the post‑HTx period were added, resulting in three studies analyzed. The significance level adopted was 0.05. Heart transplant recipients showed significant improvement in VO 2 peak, heart rate and peak blood pressure in 8 to 12 weeks of intervention. Introduction Heart transplant (HTx) is considered the gold-standard treatment for patients with heart failure refractory to clinical therapy and/or intervention procedure. 1,2 The bicaval technique is currently used in surgical centers, consisting in cardiac denervation via complete dissection of the right atrial appendage and interauricular septum, saving a small portion of the left atrial appendage containing the pulmonary veins. 3 The major advantage of that technique over the others is atrial geometry preservation, lower transpulmonary gradient and lower incidence of post-surgical tricuspid regurgitation. 4 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. 9 This behavior is similar in conditions of submaximal and close-to-peak efforts, causing lower peak HR (HRpeak) and peak BP (BPpeak), with good reproducibility for VO 2 peak. In addition, the post-exercise recovery is slow compared to that of healthy individuals of the same age group. 10,11 The physiological changes previously mentioned and the immunosuppressive therapy cause cardiorespiratory and hemodynamic damage over time, and transplant recipients often develop diseases, such as systemic arterial hypertension (95%), hyperlipidemia (81%), vasculopathy (50%), kidney failure (33%) and type 2 diabetes mellitus (32%). 12,13 Thus, cardiac rehabilitation programs have been recommended since the first guidelines of the American Heart Association and American College of Sports Medicine. The major objective of such programs is to re-establish the patients’ daily activities and to change their lifestyle, by adding activities that improve their physical, psychological and social conditions. Those activities should be structurally and continuously performed, focussing on developing the patient’s major deficient variables. 14 The current guideline recommends that cardiac rehabilitation be composed partially of physical training, consisting of three to five sessions of continuous exercise (walking, jogging, cycling) per week, at mild to moderate intensity, for at least 30 minutes daily. 15,16 The sessions should begin and end with short warm-up and cool-down periods (5-10 minutes) at low intensity, respectively. Post-HTx physical exercise is safe and effective to promote significant improvement in cardiorespiratory, metabolic, hemodynamic, endothelial and morphological variables. 14,15 However, studies of systematic review with meta-analysis conducted in patients with coronary artery disease, 16,17 type 2 diabetes mellitus 18 and metabolic syndrome 19 have shown that, in contrast to moderate-intensity continuous training (MICT), high-intensity interval training (HIIT) enables patients to reach similar and/or superior benefits regarding the variables decompensated by those diseases. 20 The HIIT is 188