Kari Nytrøen

High-Intensity Interval Training Improves Peak Oxygen Uptake and Muscular Exercise Capacity in Heart Transplant Recipients

Heart transplant (HTx) recipients usually have reduced exercise capacity with reported VO2peak levels of 50–70% predicted value. Our hypothesis was that high‐intensity interval training (HIIT) is an applicable and safe form of exercise in HTx recipients and that it would markedly improve VO2peak.

Effect of high-intensity interval training on progression of cardiac allograft vasculopathy

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 >18 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 = 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 = 0.020), and mean increase in maximal intimal thickness (MIT) was 0.02-0.01 to 0.04] mm in the HIIT group vs 0.05 [0.03 to 0.08] mm in the control group (p = 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.

One year of high-intensity interval training improves exercise capacity, but not left ventricular function in stable heart transplant recipients: A randomised controlled trial

Background Heart transplant recipients have lower exercise capacity and impaired cardiac function compared with the normal population. High-intensity interval training (HIIT) improves exercise capacity and cardiac function in patients with heart failure and hypertension, but the effect on cardiac function in stable heart transplant recipients is not known. Thus, we investigated whether HIIT improved cardiac function and exercise capacity in stable heart transplant recipients by use of comprehensive rest- and exercise-echocardiography and cardiopulmonary exercise testing. Design and methods Fifty-two clinically stable heart transplant recipients were randomised either to HIIT (4 × 4 minutes at 85–95% of peak heart rate three times per week for eight weeks) or to control. Three such eight-week periods were distributed throughout one year. Echocardiography (rest and submaximal exercise) and cardiopulmonary exercise testing were performed at baseline and follow-up. Results One year of HIIT increased VO2peak from 27.7 ± 5.5 at baseline to 30.9 ± 5.0 ml/kg/min at follow-up, while the control group remained unchanged (28.5 ± 7.0 vs. 28.0 ± 6.7 ml/kg per min, p < 0.001 for difference between the groups). Systolic and diastolic left ventricular functions at rest and during exercise were generally unchanged by HIIT. Conclusions Whereas HIIT is feasible in heart transplant recipients and effectively improves exercise capacity, it does not alter cardiac systolic and diastolic function significantly. Thus, the observed augmentation in exercise capacity is best explained by extra-cardiac adaptive mechanisms.

What matters to patients? A systematic review of preferences for medication-associated outcomes in mental disorders

Objective To investigate patients’ preferences for outcomes associated with psychoactive medications. Setting/design Systematic review of stated preference studies. No settings restrictions were applied. Participants/eligibility criteria We included studies containing quantitative data regarding the relative value adults with mental disorders place on treatment outcomes. Studies with high risk of bias were excluded. Primary and secondary outcome measures We restricted the scope of our review to preferences for outcomes, including the consequences from, attributes of, and health states associated with particular medications or medication classes, and process outcomes. Results After reviewing 11 215 citations, 16 studies were included in the systematic review. These studies reported the stated preferences from patients with schizophrenia (n=9), depression (n=4), bipolar disorder (n=2) and attention deficit hyperactive disorder (n=1). The median sample size was 81. Side effects and symptom outcomes outnumbered functioning and process outcomes. Severe disease and hospitalisation were reported to be least desirable. Patients with schizophrenia tended to value disease states as higher and side effects as lower, compared to other stakeholder groups. In depression, the ability to cope with activities was found to be more important than a depressed mood, per se. Patient preferences could not consistently be predicted from demographic or disease variables. Only a limited number of potentially important outcomes had been investigated. Benefits to patients were not part of the purpose in 9 of the 16 studies, and in 10 studies patients were not involved when the outcomes to present were selected. Conclusions Insufficient evidence exists on the relative value patients with mental disorders place on medication-associated outcomes. To increase patient-centredness in decisions involving psychoactive drugs, further research—with outcomes elicited from patients, and for a larger number of conditions—should be undertaken. Trial registration number PROSPERO CRD42013005685.

Exercise after heart transplantation: An overview

While life expectancy is greatly improved after a heart transplant, survival is still limited, and compared to the general population, the exercise capacity and health-related quality of life of heart transplant recipients are reduced. Increased exercise capacity is associated with a better prognosis. However, although several studies have documented positive effects of exercise after heart transplantation (HTx), little is known about the type, frequency and intensity of exercise that provides the greatest health benefits. Moreover, the long-term effects of exercise on co-morbidities and survival are also unclear. Exercise restrictions apply to patients with a denervated heart, and for decades, it was believed that the transplanted heart remained denervated. This has since been largely disproved, but despite the new knowledge, the exercise restrictions have largely remained, and up-to-date guidelines on exercise prescription after HTx do not exist. High-intensity, interval based aerobic exercise has repeatedly been documented to have superior positive effects and health benefits compared to moderate exercise. This applies to both healthy subjects as well as in several patient groups, such as patients with metabolic syndrome, coronary artery disease or heart failure. However, whether the effects of this type of exercise are also applicable to heart transplant populations has not yet been fully established. The purpose of this article is to give an overview of the current knowledge about the exercise capacity and effect of exercise among heart transplant recipients and to discuss future exercise strategies.

Chronotropic responses to exercise in heart transplant recipients: 1-yr follow-up.

Objective: Partial normalization of the heart rate (HR) response can take place some time after heart transplantation (HTx), but the extent to which this occurs, its time course, and functional significance remain unclear. Design: Seventy-seven heart transplantation patients underwent an exercise test at approximately 1, 6, and 12 mos after heart transplantation, consisting of a resting period, a submaximal exercise test, and a maximal exercise test with stair climbing, followed by a recovery period. An HR monitor was used for continuous surveillance of HR. Results: During the follow-up, HR at rest did not change, whereas all other HR parameters obtained during and after exercise improved, demonstrating a more rapid increase, a higher peak, and a more rapid decline in HR after stopping exercise. Age-predicted maximum HR at baseline was 73% ± 9%, improving to 83% ± 10% at 6 mos (P < 0.001) and to 90% ± 10% at 12 mos (P < 0.001), whereas the Chronotropic Response Index at baseline was 0.49 ± 0.15, improving to 0.67 ± 0.17 at 6 mos (P < 0.001) and to 0.81 ± 0.23 at 12 mos (P < 0.001). Conclusions: Partial normalization of HR was achieved by 71% of heart transplantation patients at 12 mos, with significant changes occurring within 6 mos in most subjects. These findings should contribute to reducing the exercise restrictions that apply to the denervated heart.

Muscular exercise capacity and body fat predict VO2peak in heart transplant recipients

Background: Heart transplant (HTx) recipients usually have reduced exercise capacity, with reported VO2peak levels of 50–70% of predicted values. This study aimed to evaluate central and peripheral factors predictive of VO2peak. Methods and results: Fifty-one clinically stable HTx recipients >18 years old and 1–8 years after HTx, underwent maximal exercise testing on a treadmill. Clinical laboratory, haemodynamic and echocardiographic data, lung function, and isokinetic muscle strength and muscular exercise capacity were recorded. The mean ± SD age was 52 ± 16 years, 71% were male, and time from HTx was 4.1 ± 2.2 years. The patients were assigned to one of two groups: VO2peak ≤or >27.3 ml/kg/min, which was the median value, corresponding to 80% of predicted value. The group with the higher VO2peak had significantly lower body mass index, body fat, and triglycerides, and significantly higher body water, muscular exercise capacity, high-density lipoprotein (HDL) cholesterol, lung function, mitral annular velocity, peak ventilation, O2 pulse, and VE/VCO2 slope. Donor age, recipient age, sex, medication, ischaemic time, cardiac dimensions, systolic function, and chronotropic responses during exercise were similar. Multiple regression analysis showed that muscular exercise capacity and body fat were the strongest VO2peak predictors. Conclusions: Chronotropic incompetence is not a limiting factor for exercise capacity in a population of relatively fit HTx patients. The most significant predictors, representing only peripheral factors, are similar to those often determining VO2peak in healthy, non-athletic individuals. Our findings emphasize the importance of a low percentage of body fat and high muscular exercise capacity in order to attain a sufficient VO2peak level after HTx.

Peak oxygen uptake and self-reported physical health are strong predictors of long-term survival after heart transplantation

Peak oxygen uptake (VO2peak) is known as the gold standard measure of cardiopulmonary fitness. We therefore hypothesized that measures of physical health would predict long‐term survival in heart transplant recipients (HTx).

The development and feasibility of a personal health-optimization system for people with bipolar disorder

BackgroundPeople with bipolar disorder often experience ill health and have considerably reduced life expectancies. Suboptimal treatment is common and includes a lack of effective medicines, overtreatment, and non-adherence to medical interventions and lifestyle measures. E- and m-health applications support patients in optimizing their treatment but often exhibit conceptual and technical shortcomings. The objective of this work was to develop and test the usability of a system targeting suboptimal treatment and compare the service to other genres and strategies.MethodsBased on the frameworks of shared decision-making, multi-criteria decision analysis, and single-subject research design, we interviewed potential users, reviewed research and current approaches, and created a first version using a rapid prototyping framework. We then iteratively improved and expanded the service based on formative usability testing with patients, healthcare providers, and laypeople from Norway, the UK, and Ukraine. The evidence-based health-optimization system was developed using systematic methods. The System Usability Scale and a questionnaire were administered in formative and summative tests. A comparison of the system to current standards for clinical practice guidelines and patient decision aids was performed.ResultsSeventy-eight potential users identified 82 issues. Driven by user feedback, the limited first version was developed into a more comprehensive system. The current version encompasses 21 integrated core features, supporting 6 health-optimization strategies. One crucial feature enables patients and clinicians to explore the likely value of treatments based on mathematical integration of self-reported and research data and the patient’s preferences. The mean ± SD (median) system usability score of the patient-oriented subsystem was 71 ± 18 (73). The mean ± SD (median) system usability score in the summative usability testing was 78 ± 18 (75), well above the norm score of 68. Feedback from the questionnaire was generally positive. Eighteen out of 23 components in the system are not required in international standards for patient decision aids and clinical practice guidelines.ConclusionWe have developed the first evidence-based health-optimization system enabling patients, clinicians, and caregivers to collaborate in optimizing the patient’s health on a shared platform. User tests indicate that the feasibility of the system is acceptable.

Long-term effects of high-intensity interval training in heart transplant recipients: A 5-year follow-up study of a randomized controlled trial

Previous studies have demonstrated that high‐intensity interval training (HIT) is superior to moderate‐continuous exercise in general and in cardiovascular diseases. Recently, we also found HIT safe and efficient after heart transplantation (HTx). This study reports the 5‐year long‐term effects.