Physical activity patterns and exercise performance in cardiac transplant recipients

Kyolic aged garlic extract improves aerobic fitness in middle‑aged recreational endurance athletes: A randomized double‑blind placebo‑controlled 3 month trial

Arterial stiffness is a cardiovascular risk factor that increases with age. Kyolic aged garlic extract has been shown to reduce arterial stiffness, while normalizing blood pressure, cholesterol and blood thickness. The present study hypothesized that increased flexibility of arteries could lead to slower blood flow and increased oxygen uptake and overall aerobic fitness. The present 12 week trial aimed to assess the effect of Kyolic aged garlic extract (AGE) on arterial stiffness, aerobic fitness, lactate threshold, recovery from muscle soreness and cardiovascular proteomic biomarkers in middle-aged (40-65 years) endurance athletes with elevated arterial stiffness. A total of 75 middle-aged recreational endurance athletes completed the trial, after being randomly allocated for 12 weeks to either the placebo or Kyolic aged garlic extract groups: low-dose cohort 1 (n=37), 2 capsules/day containing 1.2 g AGE powder and 1.2 mg S-allylcysteine (SAC); and the high-dose cohort 2 (n=38), 4 capsules/day of 2.4 g AGE powder and 2.4 mg SAC. Arterial stiffness was assessed through pulse wave velocity measurements and aerobic fitness was measured by volume-maximal-oxygen-consumption (VO2max) and lactate thresholds during high-intensity exercise using a cycle-ergometer-test-station, as well as measuring the levels of muscle fatigue and recovery time at 12 weeks compared with the baseline results. Urinary proteomic analysis was performed in a subgroup of participants and measured the levels of certain relevant proteins used as biomarkers for risk of cardiovascular events, at 12 weeks compared with baseline results. The Kyolic aged garlic extract group significantly improved their aerobic fitness, as was evidenced by increased VO2max, increased aerobic power, higher lactate threshold-to-oxygen uptake, higher lactate threshold-to-power output and quicker recovery times compared with the placebo group. Pulse wave velocity, a measure for arterial flexibility, was improved in the Kyolic aged garlic extract group compared with the placebo. The proteomics analysis demonstrated that a subset of polypeptides associated with cardiovascular risk, such as heart attacks and stroke, decreased in the Kyolic aged garlic extract group at 12 weeks compared with the baseline, which was contrary to the effects observed in the placebo group. Therefore, the results of the present study suggested that Kyolic aged garlic extract significantly improved aerobic fitness, lactate threshold, recovery and cardiovascular proteomic biomarkers in middle-aged endurance athletes within 12 weeks. The present clinical trial was registered on 11/03/2020 at the Australian New Zealand Clinical Trial Registry (trial registration no. ACTRN12620000340932).

Prevention and rehabilitation after heart transplantation: A clinical consensus statement of the European Association of Preventive Cardiology, Heart Failure Association of the ESC, and the European Cardio Thoracic Transplant Association, a section of ESOT

Little is known either about either physical activity patterns, or other lifestyle-related prevention measures in heart transplantation (HTx) recipients. The history of HTx started more than 50 years ago but there are still no guidelines or position papers highlighting the features of prevention and rehabilitation after HTx. The aims of this scientific statement are (i) to explain the importance of prevention and rehabilitation after HTx, and (ii) to promote the factors (modifiable/non-modifiable) that should be addressed after HTx to improve patients' physical capacity, quality of life and survival. All HTx team members have their role to play in the care of these patients and multidisciplinary prevention and rehabilitation programmes designed for transplant recipients. HTx recipients are clearly not healthy disease-free subjects yet they also significantly differ from heart failure patients or those who are supported with mechanical circulatory support. Therefore, prevention and rehabilitation after HTx both need to be specifically tailored to this patient population and be multidisciplinary in nature. Prevention and rehabilitation programmes should be initiated early after HTx and continued during the entire post-transplant journey. This clinical consensus.

Prevention and Rehabilitation After Heart Transplantation: A Clinical Consensus Statement of the European Association of Preventive Cardiology, Heart Failure Association of the ESC, and the European Cardio Thoracic Transplant Association, a Section of ESOT

Little is known either about either physical activity patterns, or other lifestyle-related prevention measures in heart transplantation (HTx) recipients. The history of HTx started more than 50 years ago but there are still no guidelines or position papers highlighting the features of prevention and rehabilitation after HTx. The aims of this scientific statement are (i) to explain the importance of prevention and rehabilitation after HTx, and (ii) to promote the factors (modifiable/non-modifiable) that should be addressed after HTx to improve patients' physical capacity, quality of life and survival. All HTx team members have their role to play in the care of these patients and multidisciplinary prevention and rehabilitation programmes designed for transplant recipients. HTx recipients are clearly not healthy disease-free subjects yet they also significantly differ from heart failure patients or those who are supported with mechanical circulatory support. Therefore, prevention and rehabilitation after HTx both need to be specifically tailored to this patient population and be multidisciplinary in nature. Prevention and rehabilitation programmes should be initiated early after HTx and continued during the entire post-transplant journey. This clinical consensus statement focuses on the importance and the characteristics of prevention and rehabilitation designed for HTx recipients.

Exercise interventions for adults after liver transplantation

BACKGROUND

The finding that exercise is inversely related to metabolic syndrome after transplantation is novel and suggests that exercise interventions might provide a means for reducing metabolic syndrome complications in liver transplantation recipients. The use of exercise for increasing the physical activity daily levels by more frequent, higher intensity, and longer duration of training sessions, or the sum of these components may be necessary to counteract the effects of the pretransplant reduced activity, metabolic disturbances, and post-transplant immunosuppression, as well as improve physical function and aerobic capacity following liver transplantation. Regular physical activity has a long-term positive impact on recovery following various surgical procedures including transplantation, giving people the opportunity to return to an active life with their families, in society, and in their professional life. Likewise, specific muscle strength training may attenuate the loss of strength after liver transplantation.

OBJECTIVES

To evaluate the benefits and harms of exercise-based interventions in adults after liver transplantation compared to no exercise, sham interventions, or another type of exercise.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 2 September 2022.

SELECTION CRITERIA

We included randomised clinical trials in liver transplantation recipients comparing any type of exercise with no exercise, sham interventions, or another type of exercise.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. all-cause mortality; 2. serious adverse events; and 3. health-related quality of life. Our secondary outcomes were 4. a composite of cardiovascular mortality and cardiac disease; 5. aerobic capacity; 6. muscle strength; 7. morbidity; 8. non-serious adverse events; and 9. cardiovascular disease post-transplantation. We assessed risk of bias of the individual trials using RoB 1, described the interventions using the TIDieR checklist, and used GRADE to assess certainty of evidence.

MAIN RESULTS

We included three randomised clinical trials. The trials randomised 241 adults with liver transplantation, of which 199 participants completed the trials. The trials were conducted in the USA, Spain, and Turkey. They compared exercise versus usual care. The duration of the interventions ranged from two to 10 months. One trial reported that 69% of participants who received the exercise intervention were adherent to the exercise prescription. A second trial reported a 94% adherence to the exercise programme, with participants attending 45/48 sessions. The remaining trial reported a 96.8% adherence to the exercise intervention during the hospitalisation period. Two trials received funding; one from the National Center for Research Resources (US) and the other from Instituto de Salud Carlos III (Spain). The remaining trial did not receive funding. All trials were at an overall high risk of bias, derived from high risk of selective reporting bias and attrition bias in two trials. The results on all-cause mortality showed a higher risk of death in the exercise group versus the control group, but these results are very uncertain (risk ratio (RR) 3.14, 95% confidence interval (CI) 0.74 to 13.37; 2 trials, 165 participants; I² = 0%; very low-certainty evidence). The trials did not report data on serious adverse events excluding mortality or non-serious adverse events. However, all trials reported that there were no adverse effects associated with exercise. We are very uncertain on whether exercise compared with usual care has a beneficial or harmful effect on health-related quality of life assessed using the 36-item Short Form Physical Functioning subscale at the end of the intervention (mean difference (MD) 10.56, 95% CI -0.12 to 21.24; 2 trials, 169 participants; I² = 71%; very low-certainty evidence). None of the trials reported data on composite of cardiovascular mortality and cardiovascular disease, and cardiovascular disease post-transplantation. We are very uncertain if there are differences in aerobic capacity in terms of VO2peak at the end of the intervention between groups (MD 0.80, 95% CI -0.80 to 2.39; 3 trials, 199 participants; I² = 0%; very low-certainty evidence). We are very uncertain if there are differences in muscle strength at end of the intervention between groups (MD 9.91, 95% CI -3.68 to 23.50; 3 trials, 199 participants; I² = 44%; very low-certainty evidence). One trial measured perceived fatigue using the Checklist Individual Strength (CIST). Participants in the exercise group showed a clinically important lower degree of fatigue perception than participants in the control group, with a mean reduction of 40 points in the CIST (95% CI 15.62 to 64.38; 1 trial, 30 participants).  We identified three ongoing studies.

AUTHORS' CONCLUSIONS

Based on very low-certainty evidence in our systematic review, we are very uncertain of the role of exercise training (aerobic, resistance-based exercises, or both) in affecting mortality, health-related quality of life, and physical function (i.e. aerobic capacity and muscle strength) in liver transplant recipients. There were few data on the composite of cardiovascular mortality and cardiovascular disease, cardiovascular disease post-transplantation, and adverse event outcomes. We lack larger trials with blinded outcome assessment, designed according to the SPIRIT statement and reported according to the CONSORT statement.

Subjective Daily Physical Activity Measures in Heart Disease: A Systematic Review

BACKGROUND

The measurement of daily physical activity (DPA) is important for the prognosis and quantifying clinical outcomes in individuals with heart disease. The measurement of DPA is more feasible using subjective measures when compared with objective measures. The purpose of this systematic review of the literature was to identify the subjective measures of DPA that have established reliability and validity in individuals with heart disease to assist clinician and researcher instrument selection.

METHODS

A systematic search of PubMed, CINAHL, MEDLINE, and ProQuest databases was performed. Methodological rigor was assessed using 3 different quality appraisal tools. Qualitative synthesis of included studies was performed.

RESULTS

Twenty-two unique studies covering 19 subjective DPA measures were ultimately included. Methodological rigor was generally fair, and validity coefficients were moderate at best.

CONCLUSIONS

Only 4 subjective measures that have established test-retest reliability and that provide an estimate of energy expenditure, metabolic equivalents, or minutes of DPA were compared against accelerometry or a DPA diary in patients with heart disease: SWISS Physical Activity Questionnaire, Total Activity Measure 1 and 2, and Mobile Physical Activity Logger. Depending on the clinician or researcher needs, instrument selection would depend on the recall period and the DPA construct being measured.

Effects of exercise using a mobile device on cardiopulmonary function, metabolic risk factors, and self-efficacy in obese women

The purpose of this study was to determine the effects of a 12-week walking exercise using a mobile device on cardiopulmonary function, metabolic risk factors, and self-efficacy in obese middle-aged women. For this study, 14 middle-aged subjects with obesity were included and performed walking exercise of 50%–60% maximum oxygen uptake intensity 3 times a week for 12 weeks. As a result, weight, % body fat, body mass index, and waist circumference significantly reduced. In addition, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and hemoglobin A_1c significantly reduced, while high-density lipoprotein cholesterol and flexibility significantly increased. Furthermore, exercise using a mobile device significantly increased self-efficacy. In conclusion, walking exercise using a mobile device is a good method to constantly increase the exercise participation rate, as it improves metabolic risk factor and obesity index, and increases self-efficacy.

Quadriceps Muscle Strength and Body Mass Index Are Associated With Estimates of Physical Activity Postheart Transplantation

BACKGROUND

Although exercise capacity improves postheart transplantation (HTx), it remains unclear if the level of physical activity (PA) shows similar improvement. The purpose of this study was to (1) describe PA levels and (2) identify factors which may be associated with levels of PA post-HTx.

METHODS

A prospective observational cross-sectional study was conducted at a single center HTx outpatient clinic. Medically stable adult recipients 6 months or longer post-HTx were recruited. Physical activity level (PAL) and average daily time spent at least moderately active (≥3 metabolic equivalents) were estimated using a multisensor device. Factors investigated were demographic (age, sex, body mass index [BMI], time post-HTx, and reason for HTx), corticosteroid use, exercise capacity (6-min walk distance), and quadriceps muscle strength corrected for body weight (QS%).

RESULTS

The mean post-HTx time of the 75 participants was 9.2 ± 7.0 years (0.5-26 y). Twenty-seven (36%) participants were classified as extremely inactive (PAL, <1.40), 26 (34.6%) sedentary (1.40 ≤ PAL ≤ 1.69), and 22 (29.3%) active (PAL, ≥1.70). Multivariable analysis showed greater QS% (β = 0.004 (0.002-0.006) P = 0.001) to be independently associated with increased PAL. For increased time, 3 or more metabolic equivalents both greater QS% (β = 0.0164 [0.003-0.029]; P = 0.014) and lower BMI (β = -0.0626 [-0.115 to -0.0099]; P = 0.021) were independently associated.

CONCLUSIONS

The degree of observed sedentary behavior post-HTx is surprising, with the majority of participants not reaching levels of PA recommended for health benefits. QS% and BMI were the only factors found to be independently associated with estimates of PA. Further quality trials are required to demonstrate the long-term benefits of regular PA and investigate ways of increasing adherence to PA post-HTx.

Physical Activity, Sedentary Time, and Associated Factors in Recipients of Solid-Organ Transplantation

BACKGROUND

Short-term survival after solid-organ transplantation has substantially improved, and the focus has shifted to long-term survival, including the role of physical activity (PA). Knowledge about PA and sedentary time in recipients of solid-organ transplantation is limited, and identification of the levels and associated factors is necessary for intervention development.

OBJECTIVE

The objectives of this study were to investigate the level of PA and sedentary time in recipients of solid-organ transplantation and to identify factors associated with these behaviors.

DESIGN

The design consisted of a cross-sectional survey.

METHODS

Questionnaires on PA level, sedentary time, and potential associated factors were used for recipients of solid-organ transplantation (kidney, liver, lung, and heart [N = 656]). Multiple regression analyses with a variable selection procedure were used.

RESULTS

Fewer than 60% of the recipients fulfilled the PA guideline. Factors significantly associated with a lower level of PA included being a woman, younger age (nonlinear), not actively working or being retired, physical limitations, and low expectations and self-confidence. Factors significantly associated with less sedentary time included exercise self-efficacy and not actively working or being retired. Significantly associated with more sedentary time were a high education level, fear of negative effects, physical limitations, and the motivator "health and physical outcomes." The type of transplantation did not significantly influence either of the outcome measures.

LIMITATIONS

The design did not allow for causal inferences to be made. The studied associated factors were limited to individual and interpersonal factors. Self-reported measures of PA and sedentary time were used.

CONCLUSIONS

In intervention development directed at increasing the level of PA and reducing sedentary time in recipients of solid-organ transplantation, attention should be paid to physical limitations, fear of negative effects, low expectations and self-confidence, health and physical outcomes, and exercise self-efficacy.

Physician Practice Patterns and Barriers to Counselling on Physical Activity in Solid Organ Transplant Recipients

Background

Many solid organ transplant (SOT) recipients fail to meet the recommended physical activity (PA) levels. “Physician recommendation” has previously been reported by SOT recipients as a key facilitator to being more physically active. The purpose of this study was to determine the proportion of Canadian SOT physicians providing PA counselling and identify barriers to including such counselling as part of the SOT recipients’ routine care.

Material/Methods

We conducted a cross-sectional web-based survey study to evaluate physicians’ PA counselling practices, including the prevalence and barriers to such practice. A survey link was sent to a convenience sample of transplant physicians who are members of the Canadian Society of Transplantation.

Results

Thirty-four physicians (13.6%) participated in the survey. While 97% (n=33) of the participants reported providing PA counselling to their transplant patients, only 18% (n=6) responded they were very confident in PA counselling. Lack of time (n=19; 56%) and a lack of exercise guidelines (n=18; 53%) were identified as the main barriers to PA counselling.

Conclusions

Incorporating sufficient PA knowledge into physicians’ educational curricula system, developing specific PA guidelines as well as establishing an easier referral system to exercise specialists might improve the frequency and quality of PA counselling post-transplant.

A study of clinical and physiological relations of daily physical activity in precapillary pulmonary hypertension

Daily physical activity is reduced in precapillary pulmonary hypertension (PH), but the underlying mechanisms are inadequately explored. We sought to investigate clinical and physiological relations of daily physical activity and profile differences between less and more active patients with precapillary PH. A prospective, cross-sectional study of 20 patients with precapillary PH who undertook 1) a comprehensive clinical assessment, 2) a preliminary treadmill test, 3) 7-day monitoring of daily walking intensity with triaxial accelerometry, and 4) a personalized treadmill test corresponding to the individual patient mean daily walking intensity with real-time physiological measurements. Significant clinical correlations with individual patient mean walking intensity [1.71 ± 0.27 (SD) m/s²] were observed for log-transformed N-terminal probrain natriuretic peptide (log NT-proBNP; r = -0.75, P = <.001), age (r = -0.70, P = 0.001), transfer factor for carbon monoxide %predicted (r = 0.51, P = 0.022), and 6-min walk distance (r = 0.50, P = 0.026). Significant physiological correlations were obtained for heart rate reserve (r = 0.68, P = 0.001), quadriceps tissue oxygenation index (Q-[Formula: see text]; r = 0.58, P = 0.008), change in Q-[Formula: see text] from rest (r = 0.60, P = 0.006), and ventilatory equivalent for oxygen uptake (r = -0.56, P = 0.013). Stepwise multiple regression analyses retained log NT-proBNP (R² = 0.55), heart rate reserve (R² = 0.44), and Q-[Formula: see text] (R² = 0.13) accounting for a significant variance in individual walking intensity. Less active patients had greater physical activity-induced cardiopulmonary impairment, worse quadriceps oxygenation profile, and compromised health-related quality of life compared with more active patients. These preliminary findings suggest a significant relation between right ventricular and peripheral muscle oxygenation status and reduced daily physical activity in precapillary PH. Further research is warranted to unravel the physiological determinants, establish clinical predictors, and identify beneficial interventions.NEW & NOTEWORTHY Daily physical activity holds promise to be a meaningful, patient-related outcome measure in pulmonary hypertension. In this study, novel findings in a representative sample of patients with precapillary pulmonary hypertension link reduced daily walking activity, as measured by triaxial accelerometry, with compromised right ventricular and pulmonary vascular status, peripheral muscle oxygenation, and health-related quality of life, providing a preliminary insight into the physiological mechanisms and clinical predictors of daily physical activity in precapillary pulmonary hypertension.

Perceived Barriers to and Facilitators of Physical Activity in Recipients of Solid Organ Transplantation, a Qualitative Study

Background

Sufficient physical activity is important for solid organ transplant recipients (heart, lung, liver, kidney). However, recipients do not meet the recommended amount or required type of physical activity. The perceived barriers to and facilitators of physical activity in this population are largely unknown.

Methods

Semi-structured in depth interviews were conducted with solid organ transplant recipients in order to explore experienced barriers and facilitators. Qualitative methodology with thematic line-by-line analysis was used for analysis, and derived themes were classified into personal and environmental factors.

Results

The most important indicated barriers were physical limitations, insufficient energy level, fear, and comorbidities. The most frequently mentioned facilitators included motivation, coping, consequences of (in)activity, routine/habit, goals/goal priority, and responsibility for the transplanted organ. Neutral factors acting as a barrier or facilitator were self-efficacy and expertise of personnel. A comparison of barriers and facilitators between transplant recipient groups yielded no overt differences.

Conclusion

Several personal and environmental factors were indicated that should be considered in intervention development to increase physical activity behavior in solid organ transplant recipients.

New therapy, new challenges: The effects of long-term continuous flow left ventricular assist device on inflammation

Surgically implanted continuous flow left ventricular assist devices (CF-LVADs) are currently used in patients with end-stage heart failure (HF). However, CF-LVAD therapy introduces a new set of complications and adverse events in these patients. Major adverse events with the CF-LVAD include right heart failure, vascular dysfunction, stroke, hepatic failure, and multi-organ failure, complications that may have inflammation as a common etiology. Our aim was to review the current evidence showing a relationship between these adverse events and elevated levels of inflammatory biomarkers in CF-LVAD recipients.

Tolerance of Organ Transplant Recipients to Physical Activity during a High-Altitude Expedition: Climbing Mount Kilimanjaro

BACKGROUND

It is generally unknown to what extent organ transplant recipients can be physically challenged. During an expedition to Mount Kilimanjaro, the tolerance for strenuous physical activity and high-altitude of organ transplant recipients after various types of transplantation was compared to non-transplanted controls.

METHODS

Twelve organ transplant recipients were selected to participate (2 heart-, 2 lung-, 2 kidney-, 4 liver-, 1 allogeneic stem cell- and 1 small bowel-transplantation). Controls comprised the members of the medical team and accompanying family members (n = 14). During the climb, cardiopulmonary parameters and symptoms of acute mountain sickness were recorded twice daily. Capillary blood analyses were performed three times during the climb and once following return.

RESULTS

Eleven of the transplant participants and all controls began the final ascent from 4700 meters and reached over 5000 meters. Eight transplant participants (73%) and thirteen controls (93%) reached the summit (5895m). Cardiopulmonary parameters and altitude sickness scores demonstrated no differences between transplant participants and controls. Signs of hyperventilation were more pronounced in transplant participants and adaptation to high-altitude was less effective, which was related to a decreased renal function. This resulted in reduced metabolic compensation.

CONCLUSION

Overall, tolerance to strenuous physical activity and feasibility of a high-altitude expedition in carefully selected organ transplant recipients is comparable to non-transplanted controls.

Validity of the Brazilian version of the Godin-Shephard Leisure-Time Physical Activity Questionnaire

This study provides evidence of construct validity for the Brazilian version of the Godin-Shephard Leisure-Time Physical Activity Questionnaire (GSLTPAQ), a 1-item instrument used among 236 participants referred for cardiopulmonary exercise testing. The Baecke Habitual Physical Activity Questionnaire (Baecke-HPA) was used to evaluate convergent and divergent validity. The self-reported measure of walking (QCAF) evaluated the convergent validity. Cardiorespiratory fitness assessed convergent validity by the Veterans Specific Activity Questionnaire (VSAQ), peak measured (VO2peak) and maximum predicted (VO2pred) oxygen uptake. Partial adjusted correlation coefficients between the GSLTPAQ, Baecke-HPA, QCAF, VO2pred and VSAQ provided evidence for convergent validity; while divergent validity was supported by the absence of correlations between the GSLTPAQ and the Occupational Physical Activity domain (Baecke-HPA). The GSLTPAQ presents level 3 of evidence of construct validity and may be useful to assess leisure-time physical activity among patients with cardiovascular disease and healthy individuals.

Characterization of aerobically fit individuals with cardiovascular disease

With an ageing population there is an increased prevalence of individuals living with cardiovascular disease (CVD). Characteristics of older aerobically fit individuals with previously diagnosed CVD have not been studied. Therefore, our knowledge is limited as to how, or if, aerobically fit individuals with CVD attempt to adapt their physical activity and the intensity of their training programmes. The objective of this paper is to characterise the physical activity habits and behaviours of older aerobically fit individuals with CVD. We identified 28 aerobically fit patients with CVD from those who completed a minimum of 15 and 12 min of the Bruce treadmill protocol for men and women, respectively. Consenting participants responded to questionnaires regarding physical activity levels, competitive event participation and self-monitoring since diagnosis of heart disease. Average age and treadmill time of participants were 56 and 49 years and 15.6 and 13.0 min for males and females, respectively. Data were obtained regarding recent medical history (medical diagnoses, surgeries/procedures). Despite the majority of individuals participating in the same or more activity since their diagnosis, 25% indicated that their condition limited their activity and 39% reported having symptoms during activity. Nearly all participants (93%) indicated that they monitored their heart rate during exercise. However, only 14% of participants stated that their physician advised them on how to exercise safely. It is necessary for physicians and cardiac rehabilitation programmes to be involved in safe and effective exercise programming to allow individuals to return to sport after CVD.

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.

Exercise limitation following transplantation

Organ transplantation is one of the medical miracles or the 20th century. It has the capacity to substantially improve exercise performance and quality of life in patients who are severely limited with chronic organ failure. We focus on the most commonly performed solid-organ transplants and describe peak exercise performance following recovery from transplantation. Across all of the common transplants, evaluated significant reduction in VO2peak is seen (typically renal and liver 65%-80% with heart and/or lung 50%-60% of predicted). Those with the lowest VO2peak pretransplant have the lowest VO2peak posttransplant. Overall very few patients have a VO2peak in the normal range. Investigation of the cause of the reduction of VO2peak has identified many factors pre- and posttransplant that may contribute. These include organ-specific factors in the otherwise well-functioning allograft (e.g., chronotropic incompetence in heart transplantation) as well as allograft dysfunction itself (e.g., chronic lung allograft dysfunction). However, looking across all transplants, a pattern emerges. A low muscle mass with qualitative change in large exercising skeletal muscle groups is seen pretransplant. Many factor posttransplant aggravate these changes or prevent them recovering, especially calcineurin antagonist drugs which are key immunosuppressing agents. This results in the reduction of VO2peak despite restoration of near normal function of the initially failing organ system. As such organ transplantation has provided an experiment of nature that has focused our attention on an important confounder of chronic organ failure-skeletal muscle dysfunction.

Low lifetime recreational activity is a risk factor for peripheral arterial disease

BACKGROUND

The relationship between lifetime physical activity and the risk of developing peripheral arterial disease (PAD) is not known.

METHODS

We studied 1381 patients referred for elective coronary angiography in a point prevalence analysis. PAD was defined as ankle-brachial index (ABI) <0.9 at the time or a history of revascularization of the lower extremities regardless of ABI measure. We used a validated physical activity questionnaire to retrospectively measure each patient's lifetime recreational activity (LRA). Multivariate and logistic regression analyses were used to assess the independent association of LRA to ABI and the presence of PAD.

RESULTS

PAD was present in 19% (n = 258) of all subjects. Subjects reporting no regular LRA had greater diastolic blood pressure and were more likely to be female. They had lower average ABI, and a higher proportion had PAD (25.6%). In a regression model, including traditional risk factors and LRA, multivariate analysis showed that age (P < .001), female gender (P < .001), systolic blood pressure (P = .014), fasting glucose (P < .001), serum triglycerides (P = .02), and cumulative pack years (P < .001) were independent negative predictors of ABI, and LRA was a positive predictor of ABI (P < .001). History of sedentary lifestyle independently increased the odds ratio for PAD (odds ratio, 0.46; 95% confidence interval, 1.01-2.10) when assessed by logistic regression. Intriguingly, there is a correlation between physical activity and gender, such that women with low LRA are at greatest risk.

CONCLUSION

Recalled LRA is positively correlated to ABI and associated with PAD. Whereas the mechanism for this effect is not clear, LRA may be a useful clinical screening tool for PAD risk, and strategies to increase adult recreational activity may reduce the burden of PAD later in life.

Physical activity in daily life 1 year after lung transplantation

BACKGROUND

Reduced physical fitness has been reported to occur after lung transplantation. Pre- and post-transplant factors, including an inactive lifestyle, have been proposed as possible causes. However, daily physical activity has not been objectively assessed so far in lung recipients. The purpose of this study was to objectively measure daily physical activity in lung recipients.

METHODS

Twenty-two clinically stable patients with single (n = 7) and bilateral lung grafts (n = 15) underwent measurements of physical activity with activity monitors at least 12 months after surgery. Results were compared with findings from 22 healthy, age- and gender-matched control subjects.

RESULTS

Substantial and statistically significant differences in daily activity were observed. Steps, standing time and moderate-intensity activity of lung recipients were reduced by 42%, 29% and 66%, respectively, relative to controls. Daily sedentary time was increased by 30%. Daily steps correlated with self-reported physical functioning (r = 0.81), 6-minute walk distance (r = 0.68), quadriceps force (r = 0.66) and maximum workload (r = 0.63).

CONCLUSIONS

This study has shown for the first time that daily activity is substantially reduced after lung transplantation and related to measures of physical fitness and health-related quality of life. Future studies need to examine whether physical activity can be modified to improve functional recovery after lung transplantation.

Genetic susceptibility to peripheral arterial disease: a dark corner in vascular biology

Peripheral arterial disease (PAD) is characterized by reduced blood flow to the limbs, usually as a consequence of atherosclerosis, and affects approximately 12 million Americans. It is a common cause of cardiovascular morbidity and an independent predictor of cardiovascular mortality. Similar to other atherosclerotic diseases, such as coronary artery disease, PAD is the result of the complex interplay between injurious environmental stimuli and genetic predisposing factors of the host. Genetic susceptibility to PAD is likely contributed by sequence variants in multiple genes, each with modest effects. Although many of these variants probably alter susceptibility both to PAD and to coronary artery disease, it is likely that there exists a set of variants specifically to alter susceptibility to PAD. Despite the prevalence of PAD and its high societal burden, relatively little is known about such genetic variants. This review summarizes our limited present knowledge and gives an overview of recent, more powerful approaches to elucidating the genetic basis of PAD. We discuss the advantages and limitations of genetic studies and highlight the need for collaborative networks of PAD investigators for shedding light on this dark corner of vascular biology.

Physical functional outcomes after cardiothoracic transplantation

The study of patient healthcare outcomes after cardiothoracic transplantation has increased substantially over the last 2 decades. Physical function after heart, lung, and heart-lung transplantation has been studied using both subjective and objective measures. The majority of reports in the literature on physical function after cardiothoracic transplantation are descriptive and observational. The purposes of the article are to review and critique the existing literature on cardiothoracic recipients' subjective and objective physical function, including respiratory function for heart-lung and lung transplant recipients. In addition, the literature on sexual function in cardiothoracic recipients is examined, the gaps in the literature are identified, and recommendations are given for future research.

Physical Activity Patterns in Heart Transplant Women

Maintaining regular, long-term physical activity is critical to achieve favorable effects of heart transplantation. Yet, at present, little is known about the physical activity patterns of transplant recipients, especially women. The study was conducted to (1) describe levels and types of physical activity using actigraphy and self-report, (2) determine the association between physical activity and sociodemographic variables, and (3) assess the relationship between physical activity, quality of life (QOL), and relevant health indicators (hypertension, hyperlipidemia, and obesity) among female heart transplant recipients. Twenty-seven women (average age, 57 +/- 13 years, primarily Caucasian [82%], retired [89%], married [67%], average time since transplant 2.1 +/- 1.3 years) from a single heart transplant facility were asked to report amount and types of physical activity and overall QOL and wear an actigraph for 1 week to measure physical activity level. Physical activity levels by actigraphy averaged 280,320 +/- 52,416 counts for the week (range, 206,784-354,144); self-reported physical activity level on a 0 to 10 scale was 4.3 +/- 0.37 (range, 0-7). The actigraph and self-reported measures were significantly correlated (r = 0.661, P = .000). It was found that women were more likely to engage in household tasks and family activities than occupational activities or sports. Significant differences in physical activity (F = 6.319, P = .006) were observed in participants who reported fair (n = 13), good (n = 9), and very good (n = 5) overall QOL. The only demographic factor associated with physical activity was age; younger women were more active than older women (r = -0.472, P = .013). A negative correlation was found between levels of physical activity and presence of hypertension, hyperlipidemia, and obesity. It was found that a majority of female transplant recipients remains sedentary. Given the association between physical activity and overall QOL and relevant health indicators, measures to enhance physical activity need to be developed and tested; these strategies may be beneficial in improving overall outcomes.

Two-year follow-up of quality of life in patients referred for heart transplant

BACKGROUND

Assessment of physical and mental health has become one of the ultimate tests of health-related quality of life (HRQOL) for patients with advanced heart failure. Little is known, however, about the comparative effects of surgical or medical treatment on the HRQOL of these chronically ill patients over time.

METHODS

We examined 77 patients (74% of whom were male), aged 56.1 +/- 12.7 years who were referred for heart transplant evaluation at a single heart failure center to describe the effects of time and treatment status on changes in HRQOL scores (physical and mental health and depression) using the Short Form-12 and the Beck Depression Inventory at 2 time points during their illness trajectory. The 2 evaluations on average were 2 years apart (mean 24.5 +/- 2.8 months). All patients were evaluated at baseline, and 3 groups were identified at the time of the 2-year follow-up: transplant recipients (n = 17), transplant candidates (n = 13), and medically stable patients considered too well to receive a transplant (n = 47). Nonparametric statistics were used to analyze group differences in HRQOL scores. The significance level was set at a P value less than .05.

RESULTS

Demographic and HRQOL scores were not significantly different among the 3 groups at baseline. During follow-up, physical health and depression scores significantly improved over time in all patients, but changes in mental health were minimal. Group comparisons showed that although all patients continued to have low HRQOL scores at the time of follow-up evaluation, medically stable patients had higher mental health scores and less depressive symptoms than their counterparts.

CONCLUSION

Our results support the need for ongoing HRQOL assessment with an emphasis on timely recognition and treatment of psychologic distress throughout the heart failure illness trajectory. Heart transplant recipients and candidates equally need special attention and follow-up because they both seem to have emotional and psychologic repercussions.

Fitness versus physical activity patterns in predicting mortality in men

PURPOSE

To compare the contributions of fitness level and physical activity patterns to all-cause mortality.

METHODS

Of 6213 men referred for exercise testing between 1987 and 2000, 842 underwent an assessment of adulthood activity patterns. The predictive power of exercise capacity and activity patterns, along with clinical and exercise test data, were assessed for all-cause mortality during a mean (+/-SD) follow-up of 5.5 +/- 2 years.

RESULTS

Expressing the data by age-adjusted quartiles, exercise capacity was a stronger predictor of mortality than was activity pattern (hazard ratio [HR] = 0.56; 95% confidence interval [CI]: 0.38 to 0.83; P < 0.001). In a multivariate analysis that considered clinical characteristics, risk factors, exercise test data, and activity patterns, exercise capacity (HR per quartile = 0.62; CI: 0.47 to 0.82; P < 0.001) and energy expenditure from adulthood recreational activity (HR per quartile = 0.72; 95% CI: 0.58 to 0.89; P = 0.002) were the only significant predictors of mortality; these two variables were stronger predictors than established risk factors such as smoking, hypertension, obesity, and diabetes. Age-adjusted mortality decreased per quartile increase in exercise capacity (HR for very low capacity = 1.0; HR for low = 0.59; HR for moderate = 0.46; HR for high = 0.28; P < 0.001) and physical activity (HR for very low activity = 1.0; HR for low = 0.63; HR for moderate = 0.42; HR for high = 0.38; P < 0.001). A 1000-kcal/wk increase in activity was approximately similar to a 1 metabolic equivalent increase in fitness; both conferred a mortality benefit of 20%.

CONCLUSION

Exercise capacity determined from exercise testing and energy expenditure from weekly activity outperform other clinical and exercise test variables in predicting all-cause mortality.