Ventilatory strategies in the six-minute walk test in older patients receiving a three-week rehabilitation programme after cardiac surgery through median sternotomy.

BACKGROUND: Although the six-minute walk test (6MWT) is widely used in cardiac rehabilitation, little is known about the ventilatory strategies adopted by older patients who have recently undergone median sternotomy, in order to meet the increased metabolic demand in the 6MWT. METHODS: Using a portable gas-analyser we assessed the breathing patterns in the 6MWT before and after a 3-week rehabilitation programme in 84 older patients, 58 men and 26 women, mean age 71 years (standard deviation (SD) 6 years), who had undergone median sternotomy. RESULTS: After rehabilitation, patients increased end-test ventilation (33.1 l (SD 9.8) vs. 30.9 l (SD 8.4), p < 0.001) by increasing tidal volume (1.158 l (SD 0.298) vs. 1.065 l (SD 0.255), p < 0.001), while breathing frequency remained unchanged (29.9 bpm (SD 5.4) vs. 30.2 bpm (SD 5.8), p = 0.621). As a consequence, the ventilatory equivalent for CO2, was significantly improved (39.9 (SD 5.3) vs. 43.5 (SD 7.4), p < 0.001). Furthermore, the improvement in ventilatory efficiency was significantly (p < 0.001) correlated with the improvement in the distance walked on the 6MWT. CONCLUSION: Older patients who have undergone median sternotomy meet the increased metabolic demand on the 6MWT after cardiac rehabilitation by increasing tidal volume. Accordingly, we should consider including as a routine specific exercises for inspiratory muscle training in current rehabilitation programmes to reduce inspiratory muscle effort and further improve ventilatory efficiency.

Effects of a structured physical activity intervention on measures of physical performance in frail elderly patients after cardiac rehabilitation: a pilot study with 1-year follow-up.

The objective of this prospective randomized controlled study was to compare the long-term effects of a structured physical activity intervention with those of aerobic exercises alone, in a cohort of elderly patients who had undergone elective cardiac surgery, and who were classified as frail at the end of rehabilitation based on their Short Physical Performance Battery (SPPB) score. At the end of rehabilitation, 140 frail elderly patients were randomly allocated either to the intervention group (IG) or to the control group (CG). CG participants received the usual aerobic exercise prescription, while IG participants were also taught additional exercises for strength, flexibility, balance and coordination. The improvement in SPPB score after 1 year was the outcome of the study. IG showed a significant improvement in SPPB score (9.0 ± 1.1 vs. 7.7 ± 1.4, p < 0.001), while no significant change was found in CG (7.7 ± 1.6 vs. 7.6 ± 1.5, p = 0.252). IG also showed a significantly higher proportion of participants who improved their SPPB score of at least 1 point (70 vs. 37%, p < 0.001). In conclusions, our structured physical activity intervention significantly improves the SPPB score in frail elderly patients who have undergone elective cardiac surgery. An intervention that improves the SPPB score might delay the occurrence of mobility disability.

The improvement of walking speed after cardiac rehabilitation is associated with the reduction in the metabolic cost of walking in older persons.

BACKGROUND: To walk a given distance older persons consume more metabolic energy than younger adults across all speeds. As physical activity interventions improve a variety of physical performance measures in older persons, including walking speed, in this study we hypothesized that the improvement of walking speed might be associated with the reduction of the metabolic cost of walking and we tested our hypothesis in a selected sample of older patients receiving cardiac rehabilitation. METHODS: In 120 patients (88 men and 32 women, mean age 74.1 years±SD 5.0) we assessed energy expenditure during the 6-min Walk Test (6mWT) before and after the rehabilitation using a portable system for direct calorimetry. RESULTS: On the 6mWT performed after the rehabilitation patients significantly increased total energy expenditure (28.0 kcal±SD 8.3 vs. 25.7 kcal±SD 7.6, p<0.001), the distance walked (398 m±SD 93 vs. 343 m±SD 95, p<0.001) and, consequently, walking speed (1.11 m/s±SD 0.26 vs. 0.95m/s±SD 0.26, p<0.001) while the metabolic cost of walking, i.e. the amount of energy used to move a body mass of 1 kg for a distance of 1m, was significantly reduced (1.00 cal/kg/m±SD 0.19 vs. 1.11 cal/kg/m±SD 0.32, p<0.001). CONCLUSIONS: In older patients receiving cardiac rehabilitation the improvement of walking speed is associated with the improvement of walking economy. This might be a contributory factor to the favourable effects of physical activity interventions on physical performance measures.

Postacute rehabilitation after coronary surgery: the effect of preoperative physical activity on the incidence of paroxysmal atrial fibrillation.

OBJECTIVE: Postoperative atrial fibrillation (AF) is a frequent complication after cardiac surgery. AF may also occur after hospital discharge during postacute rehabilitation. Several studies have addressed the AF that occurs in the hospital after surgery, and predictors have already been identified. Postoperative AF that occurs after hospital discharge has not been investigated thoroughly, and predictors are still unknown. In this study, we hypothesized that moderate-intensity physical activity in the year before surgery might favorably affect the incidence of AF during postacute rehabilitation. DESIGN: We tested our hypothesis in a cohort of 158 older patients admitted to a medical rehabilitation facility for postacute inpatient rehabilitation after coronary surgery and continuously monitored by telemetry for the duration of the rehabilitation. RESULTS: Independent of potential confounders, patients who reported low-intensity physical activity in the year before surgery showed a significantly higher incidence of AF during postacute rehabilitation when compared with those who reported moderate-intensity physical activity (32.1% vs. 8.1%; P = 0.029). Other independent predictors of AF during postacute rehabilitation were the occurrence of AF during the patients' stay in hospital, larger left atrial volume, and lower left atrial emptying fraction. CONCLUSIONS: These findings confirm our hypothesis that physical activity in the year before surgery affects the incidence of postoperative AF during postacute rehabilitation. The results also provide information regarding possible predictors that may assist in identifying patients who could benefit from preventive treatments.

Oxygen uptake kinetics in older patients receiving postacute cardiac rehabilitation: effects of low-intensity aerobic training.

OBJECTIVE: Older patients who receive postacute cardiac rehabilitation improve their physical performance in terms of distance walked at the 6-min walk test. However, the slower and more complicated recovery, along with age-related chronic comorbidities, remarkably limits the intensity of aerobic training, which actually represents the core of cardiac rehabilitation. The aim of this study was to verify whether postacute cardiac rehabilitation also improves the cardiovascular adjustment to exercise, despite low-intensity aerobic training. DESIGN: Using a portable gas analyzer, we assessed the O(2) uptake kinetics during the 6-min walk test at the beginning and at the end of the rehabilitation in 84 patients aged 65 yrs and above. RESULTS: All patients significantly improved the distance walked at the 6-min walk test. The comparison of the time constants of O(2) uptake kinetics showed that 40% of patients also significantly improved the hemodynamic response to exercise. This improvement was independently associated with the report of sedentary lifestyle or low-intensity physical activity in the year before surgery and with longer time constants before physical training. CONCLUSIONS: Low-intensity aerobic training improves the cardiovascular adjustment to exercise selectively in patients with physical deconditioning. This confirms the notion that elderly frail patients are those who benefit most from cardiac rehabilitation.

One-year adherence to exercise in elderly patients receiving postacute inpatient rehabilitation after cardiac surgery.

OBJECTIVE: Promoting an active lifestyle through an appropriate physical exercise prescription is one of the major targets of cardiac rehabilitation. However, information on the effectiveness of cardiac rehabilitation in promoting lifestyle changes in elderly patients is still scant. DESIGN: In 131 patients over the age of 65 yrs (86 men, and 45 women, mean age 75 yrs +/- 6 SD) who have attended postacute inpatient cardiac rehabilitation after cardiac surgery, we tested the 1-yr adherence to the physical exercise prescription received at the end of the cardiac rehabilitation by using a questionnaire on physical activity and the 6-min walk test. RESULTS: All of the 36 patients who reported an active lifestyle and 49 of the 95 patients who reported a sedentary lifestyle in the year preceding the cardiac operation reported at least 1 hr/day on 5 days each week of light regular physical activity in the year after the cardiac rehabilitation. Further, the distance walked at the follow-up 6-min walk test was significantly related to the physical activity score gathered from the questionnaire. CONCLUSIONS: Our data show that 65% of the elderly patients who have attended postacute inpatient cardiac rehabilitation after cardiac surgery are still capable of recovering or even increasing their regular physical activity and of maintaining these favorable lifestyle changes at least for 1 yr.

Left-ventricular function and physical performance on the 6-min walk test in older patients after inpatient cardiac rehabilitation.

OBJECTIVE: The 6-min walk test (6mWT) is widely used to assess physical performance in cardiac rehabilitation settings. Factors affecting the walked distance before starting physical training have been described, whereas information on factors affecting the increase of the walked distance after physical training is still scant. The aim of this study was to verify, in a large sample of elderly patients soon after cardiac surgery, the role of left-ventricular function (LVF) in increases in distances walked after an intensive rehabilitation program. DESIGN: We enrolled 459 patients (300 males and 159 females, mean [+/-SD] age 70 +/- 11 yrs). According to the echographic ejection fraction, patients were classed into two categories, LVF > or = 40% and LVF < 40%. All patients performed the 6mWT at the beginning and end of the rehabilitation program. RESULTS: Longer walked distances before and after the rehabilitation program were significantly associated with preserved or moderately depressed LVF, whereas greater relative increases of the distance walked after the rehabilitation program were significantly associated with poor LVF (P < 0.001 for all). CONCLUSIONS: Among elderly patients admitted as inpatients to an intensive rehabilitation program soon after cardiac surgery, those with poor LVF are most likely to respond more favorably to physical training. Therefore, instead of considering poor LVF a risk for starting physical training in these patients, it should be considered a strong indication, to avoid further physical deconditioning and disability.

Early and late rehabilitation and physical training in elderly patients after cardiac surgery.

OBJECTIVE: Few randomized trials have enrolled patients who have undergone cardiac surgery, and even fewer have included patients aged 75 yrs or more. Furthermore, the optimal timing of cardiac rehabilitation for postsurgical patients has not yet been codified. The aim of this study was to verify whether rehabilitation outcomes are also favorable in postsurgical patients aged 75 yrs or more and whether an early rehabilitation program is as effective and safe as a late one. DESIGN: Three hundred patients who underwent cardiac surgery, 27.7% of whom were at least 75 yrs old, were randomly assigned to a rehabilitation program starting within the second week after operation or within the fourth week. All events occurring during the rehabilitation program or in the following year were recorded. RESULTS: During the rehabilitation program, new-onset atrial fibrillation was significantly more frequent in the early rehabilitation group, independent of age class, and anemia was significantly more frequent in older patients, independent of rehabilitation timing. At the end of the rehabilitation program, more than 90% of patients showed significant increases in walking distance, and during the follow-up, no significant difference was found with regard to mortality, nonfatal events, functional ability, or control of cardiovascular risk factors, independent of rehabilitation timing and age class. CONCLUSIONS: This study provides evidence that in selected patients who have undergone cardiac surgery, rehabilitation outcomes are also favorable in patients aged 75 yrs or more, and an early rehabilitation program is as effective and safe as a traditionally late one.