Kenneth Riess

Exercise training improves aerobic capacity, muscle strength, and quality of life in renal transplant recipients

Renal transplant recipients (RTR) have reduced peak aerobic capacity, muscle strength, arterial function and an unfavorable cardiovascular disease risk (CVD) profile. This study compared the effects of 12 weeks of supervised endurance and strength training (EST, n = 16) versus usual care (UC, n = 15) on peak aerobic capicity, cardiovascular and skeletal muscle function, CVD risk profile, and quality of life (QOL) in RTR (55 ± 13 years). Peak aerobic capacity and exercise hemodynamics, arterial compliance, 24-h blood pressure, muscle strength, lean body mass, CVD risk score, and QOL were assessed before and after 12 weeks. The change in peak aerobic capacity (EST: 2.6 ± 3.1 vs. UC: -0.5 ± 2.5 mL/(kg·min)), cardiac output (EST: 1.7 ± 2.6 vs. UC: -0.01 ± 0.8 L/min), leg press (EST: 48.7 ± 34.1 vs. UC: -10.5 ± 37.7 kg) and leg extension strength (EST: 9.5 ± 10.3 vs. UC: 0.65 ± 5.5 kg) improved significantly after EST compared with UC. The overall change in QOL improved significantly after 12 weeks of EST compared with UC. No significant difference was found between groups for lean body mass, arterial compliance, 24-h blood pressure or CVD risk score. Supervised EST is an effective intervention to improve peak exercise aerobic capacity and cardiac output, muscle strength and QOL in clinically stable RTR.

Pulmonary Oxygen Uptake and Heart Rate Kinetics During the Six-Minute Walk Test in Transplant Recipients

Background. The effect of organ transplantation on arterial compliance, pulmonary oxygen uptake (&OV0312;O2p) and heart rate kinetics during the 6-minute walk test (6-MWT) remains unknown. Methods. Twenty-two thoracic (heart and/or lung) organ transplant recipients (TOTR, 51±12 years) and 30 abdominal (kidney, kidney-pancreas, or liver) organ transplant recipients (AOTR, 46±11 years) from the 2006 Canadian Transplant Games, and 37 healthy controls (HC) completed a 6-MWT. &OV0312;O2p, heart rate kinetics, and arterial compliance were determined. Results. The 6-MWT distance and highest &OV0312;O2p were significantly lower in TOTR and AOTR versus HC. The highest 6-MWT heart rate was lower in TOTR (11%) and AOTR (13%) versus HC. &OV0312;O2p kinetics were slower in TOTR (52±11 sec, P≤0.001) and AOTR (45±24 sec, P≤0.001) versus HC (28±9 sec). Heart rate kinetics were slower in TOTR (100±49 sec) versus AOTR (41±21 sec, P≤0.001) and HC (34±21 sec, P≤0.001), but not between AOTR and HC. Small and large artery compliance were 26% (P=0.007) and 19% (P=0.004) lower, respectively, in TOTR versus HC. Large artery compliance was 14% lower in TOTR versus AOTR (P=0.017). 6-MWT distance was significantly related to &OV0312;O2p kinetics (r=−0.35) and the highest 6-MWT &OV0312;O2p (r=0.72). Conclusions. TOTR and AOTR have abnormal &OV0312;O2p kinetics, which is secondary to prolonged heart rate kinetics and impaired vascular function in TOTR, but not AOTR.

Impaired arterial compliance and aerobic endurance in kidney transplant recipients

Background. Cardiovascular disease is the leading cause of morbidity and mortality in kidney transplant recipients (KTR). Two risk factors for cardiovascular disease that have not been examined in this population are arterial compliance and aerobic capacity. The primary objective was to determine small and large artery compliance and aerobic endurance in KTR. A secondary objective was to explore the relationship between aging and arterial compliance and aerobic endurance in KTR. Methods. Sixty-two clinically stable KTR were recruited from the University of Alberta Renal Transplant Clinic. Small and large artery compliance was assessed using computerized arterial pulse waveform analysis. Aerobic endurance was determined using the six-minute walk test. Age-matched normative data from healthy individuals was used for comparison. Results. Small arterial compliance was lower in KTR (5.5±3 ml/mm Hg × 100) compared to age-matched healthy individuals’ predicted values (7.9±0.9 ml/mm Hg × 100, P<0.0001). No difference was found for large artery compliance between KTR (16.0±6.6 ml/mm Hg × 10) and age-matched healthy predicted values (15.2±1.3 ml/mm Hg × 10, P=0.5). Small and large artery compliance were 35% (P=0.026) and 36% (P=0.005) higher in younger (<51 years) versus older (>51 years) KTR, respectively. The six-minute walk distance was 28% lower in KTR (495±92 m) compared to healthy age-predicted values (692±56 m P<0.0001). Conclusions. Compromised arterial compliance and poor aerobic endurance may partially explain the high incidence of cardiovascular disease in KTR. Interventions demonstrated to improve these parameters may afford substantial clinical benefit in this population.

Exercise in cirrhosis: Translating evidence and experience to practice

Physical inactivity, sarcopenia, and frailty are highly prevalent, independent predictors of morbidity and mortality in patients with cirrhosis. Across a range of chronic diseases, exercise training is a key recommendation supported by guidelines and, for some conditions, even by governmental funding of exercise programmes. Consistent with the broader chronic disease literature, the evidence for a benefit of exercise in cirrhosis is promising. Several small trials have reported significant improvements in muscle health (mass, strength, functional capacity), quality of life, fatigue, and reductions in the hepatic venous pressure gradient, without adverse events. With strong emerging evidence surrounding the substantial risks of sarcopenia/frailty and our first-hand experiences with liver pre-transplant exercise programmes, we contend that routine patient care in cirrhosis should include an exercise prescription. Some clinicians may lack the resources and necessary background to translate the existing evidence into a practicable intervention. Our team, comprised of physiotherapists, exercise physiologists, hepatologists, transplant specialists, and knowledge translation experts from six North American centres, has distilled the essential background information, tools, and practices into a set of information ready for immediate implementation into clinics ranging from a family practice setting to specialty cirrhosis clinics. Augmenting the rationale and evidence are supplementary materials including video and downloadable materials for both patients and the physician. Supporting the exercising patient is a section regarding information about nutrition, providing practical tips suitable for all patients with cirrhosis.