ORIGINAL CLINICAL SCIENCE Effect of high-intensity interval training on progression of cardiac allograft vasculopathy Kari Nytrøen, PhDc, a Lene Annette Rustad, MD, a,b Ingrid Erikstad, BSc, a Pål Aukrust, MD, PhD, c,d,f Thor Ueland, PhD, c,d,f Tove Lekva, MSc, c,e,f Einar Gude, MD, PhD, a Nils Wilhelmsen, BSc, a Anders Hervold, MD, PhD, a Svend Aakhus, MD, PhD, a Lars Gullestad, MD, PhD, a,f,g and Satish Arora, MD, PhD a From the a Department of Cardiology, Oslo University Hospital HF Rikshospitalet, Oslo; b Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim; c Research Institute of Internal Medicine; d Section of Clinical Immunology and Infectious Diseases; e Section of Specialized Endocrinology, Oslo University Hospital HF Rikshospitalet; f Faculty of Medicine, University of Oslo; and the g K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway. KEYWORDS: heart transplant; exercise; exercise capacity; high-intesity training; cardiac allograft vas- culopathy; maximum oxygen up- take; rehabilitation; intravascular ultra- sound BACKGROUND: Cardiac allograft vasculopathy (CAV) is a progressive form of atherosclerosis occurring in heart transplant (HTx) recipients, leading to increased morbidity and mortality. Given the atheroprotective effect of exercise on traditional atherosclerosis, we hypothesized that high-intensity interval training (HIIT) would reduce the progression of CAV among HTx recipients. METHODS: Forty-three cardiac allograft recipients (mean  SD age 51  16 years; 67% men; time post-HTx 4.0  2.2 years), all clinically stable and 418 years old, were randomized to either a HIIT group or control group (standard care) for 1 year. The effect of training on CAV progression was assessed by intravascular ultrasound (IVUS). RESULTS: IVUS analysis revealed a significantly smaller mean increase [95% CI] in atheroma volume (PAV) of 0.9% [95% CI -;0.3% to 1.9%] in the HIIT group as compared with the control group, 2.5% [1.6% to 3.5%] (p ¼ 0.021). Similarly, the mean increase in total atheroma volume (TAV) was 0.3 [0.0 to 0.6] mm 3 /mm in the HIT group vs 1.1 [0.6 to 1.7] mm 3 /mm in the control group (p ¼ 0.020), and mean increase in maximal intimal thickness (MIT) was 0.02À0.01 to 0.04] mm in the HIIT group vs 0.05 [0.03 to 0.08] mm in the control group (p ¼ 0.054). Qualitative plaque progression (virtual histology parameters) and inflammatory activity (biomarkers) were similar between the 2 groups during the study period. CONCLUSIONS: HIIT among maintenance HTx recipients resulted in a significantly impaired rate of CAV progression. Future larger studies should address whether exercise rehabilitation strategies should be included in CAV management protocols. J Heart Lung Transplant ]]]];]:]]]–]]] r 2013 International Society for Heart and Lung Transplantation. All rights reserved. Cardiac allograft vasculopathy (CAV) is a progressive form of atherosclerosis occurring in heart transplant (HTx) recipients. In contrast to conventional atherosclerosis, CAV is characterized by intimal thickening and a more diffuse luminal narrowing of the smaller arteries. 1 The burden of disease attributable to CAV is high, being present in about 50% of HTx recipients within the first year after trans- plantation, associated with increased morbidity and mortality http://www.jhltonline.org 1053-2498/$ - see front matter r 2013 International Society for Heart and Lung Transplantation. All rights reserved. http://dx.doi.org/10.1016/j.healun.2013.06.023 E-mail address: knytroen@ous-hf.no Reprint requests: Kari Nytrøen, PhD, Department of Cardiology, Oslo University Hospital Rikshospitalet, Postbox 4950 Nydalen, N-0424 Oslo, Norway. Tel.: þ47 9518 9935; Fax: þ47 23073917.