Comparison of the six-minute walk test with a cycle-based cardiopulmonary exercise test in people following curative intent treatment for non-small cell lung cancer

Exercise capacity prior to major cancer surgery: A cross-sectional observational study of the validity of the 6-minute walk and 30-second sit-to-stand tests

INTRODUCTION

Cardiopulmonary exercise testing (CPET) is the gold standard for measuring exercise capacity, however, it is resource intensive and has limited availability. This study aimed to determine: 1) the association between the 6-min walk test (6MWT) and the 30-s sit-to-stand test (30STS) with CPET peak oxygen uptake (VO2peak) and anaerobic threshold (AT) and 2) 6MWT and 30STS cut points associated with a higher risk of postoperative complications.

METHODS

A cross-sectional study, retrospectively analyzing data collected from a tertiary cancer center over a 23-month period. Measures included CPET VO2peak and AT, 6MWT and 30STS test. Correlations were used to characterize relationships between variables. Receiver operating characteristic curve analyses determined 6MWT and 30STS cut points that aligned with CPET variable cut points.

RESULTS

Note that, 156 participants were included. The 6MWT and 30STS displayed moderate correlations with VO2peak, rho = 0.65, p = 0.01 and rho = 0.52, p < 0.005 respectively. Fair correlations were observed between AT and 6MWT (rho = 0.36, p = 0.01) and 30STS (rho = 0.41, p < 0.005). The optimal cut points to identify VO2peak < 15 mL/kg/min were 493.5 m on the 6MWT and 12.5 stands on the 30STS test and for AT < 11 mL/kg/min were 506.5 m on the 6MWT and 12.5 stands on the 30STS test.

CONCLUSION

Both the 6MWT and 30STS test could be used as alternative tools for measuring exercise capacity preoperatively in the cancer setting where CPET is not available. A range of 6MWT and 30STS cut points, according to sensitivity and specificity levels, may be used to evaluate risk of postoperative outcomes.

Associations between pretreatment physical performance tests and treatment complications in patients with non-small cell lung cancer: A systematic review

This systematic review evaluated which outcome variables and cut-off values of pretreatment exercise tests are associated with treatment complications in patients with stage I-III non-small cell lung cancer (NSCLC). PRISMA and Cochrane guidelines were followed. A total of 38 studies with adult patients undergoing treatment for stage I-III NSCLC who completed pretreatment exercise tests, and of whom treatment-related complications were recorded were included. A lower oxygen uptake at peak exercise amongst several other variables on the cardiopulmonary exercise test and a lower performance on field tests, such as the incremental shuttle walk test, stair-climb test, and 6-minute walk test, were associated with a higher risk for postoperative complications and/or postoperative mortality. Cut-off values were reported in a limited number of studies and were inconsistent. Due to the variety in outcomes, further research is needed to evaluate which outcomes and cut-off values of physical exercise tests are most clinically relevant.

Factors Influencing Functional Exercise Capacity After Lung Resection for Non-Small Cell Lung Cancer

Purpose: We investigated, in patients who underwent lung resection for non–small cell lung cancer (NSCLC), the magnitude of early limitation in functional exercise capacity and the associations with pre- and postoperative factors. Methods: Consecutive patients with preoperative clinical stage I to IIIA NSCLC who underwent lung resection were prospectively enrolled. We measured functional exercise capacity (6-minute walk distance [6MWD]) and skeletal muscle strength (handgrip [HF] and quadriceps force [QF]) within 2 days prior to surgery and on day 7 postoperatively. Results: Two hundred eighteen participants were recruited (median age 69 years) of whom 49 developed postoperative complications (POCs). 6MWD was markedly decreased (514 m vs 469 m, P < .001); HF and QF were slightly decreased following surgery. Multiple linear regression showed that preoperative vital capacity (P < .01), QF (P < .05), the duration of chest tube drainage (P < .001), and presence of POCs (P < .05) were significant predictors. However, intraoperative factors were not significantly associated with the decline in 6MWD. Conclusions: These results suggest that patients with preoperative impairments in pulmonary function and muscle strength, and those who require prolonged chest tube drainage or develop POCs are likely to have impaired exercise capacity. Therefore, individual assessment and follow-up of patients with such factors is indicated.

Validation of Submaximal Step Tests and the 6-Min Walk Test for Predicting Maximal Oxygen Consumption in Young and Healthy Participants

Background: This study aimed to test the validity of three different submaximal tests (i.e., 3-min step test with 20.3-cm step box height (3MST₂₀), 3-min step test with 30-cm step box height (3MST₃₀), and 6-min walk test (6MWT)) in estimating maximal oxygen consumption (VO_2max) in young and healthy individuals. Methods: The 3MST₂₀, 3MST₃₀, 6MWT, as well as the cardiopulmonary exercise test (CPET) were performed in 73 participants (37 men and 36 women; mean age: 30.8 ± 9.3 years). All participants visited the clinic three times in a random order for anthropometric measurements, three submaximal tests, and the VO_2max test. Multiple linear regression analyses were conducted to construct the VO_2max prediction equations for each submaximal test. Results: The prediction equations developed based on multiple regression analyses for each submaximal tests were as follows: 3MST₂₀: VO_2max = 86.0 − 10.9 × sex (male = 1, female = 2) − 0.4 × age − 0.1 × weight − 0.1 × heart rate recovery at 30 s (HRR30s); 3MST₃₀: VO_2max = 84.5 − 10.2 × sex (male = 1, female = 2) − 0.4 × age − 0.1 × weight − 0.1 × HRR30s; and 6MWT: VO_2max = 61.1 − 11.1 × sex (male = 1, female = 2) − 0.4 × age − 0.2 × weight − 0.2 × (distance walked·10⁻¹). The estimated VO_2max values based on formulated equations were 37.0 ± 7.9, 37.3 ± 7.6, and 36.9 ± 7.9 mL∙kg⁻¹∙min⁻¹ derived from the 3MST₂₀, 3MST₃₀, and 6MWT, respectively. These estimated VO_2max values were not significantly different from the measured VO_2max value, 37.3 mL∙kg⁻¹∙min⁻¹. The estimated VO_2max based on the 3MST₂₀, 3MST₃₀, and 6MWT results explained 73.4%, 72.2%, and 74.4% of the variances in the measured VO_2max (p < 0.001), respectively. Conclusions: The 3MST₂₀, 3MST₃₀, and 6MWT were valid in estimating VO_2max in relatively young and healthy Asian individuals.

Calf Muscle Oxygen Saturation during 6-Minute Walk Test and Its Relationship with Walking Impairment in Symptomatic Peripheral Artery Disease

BACKGROUND

Impaired microcirculation is associated with poor walking capacity in symptomatic peripheral artery disease (PAD) patients during treadmill test; however, this test does not simulate the efforts of daily walking of these patients. Thus, the aim of the study was to describe the microcirculation responses during a 6-minute walk test (6MWT) and to analyze the relationship between microcirculation indicators and walking impairment in symptomatic PAD patients.

METHODS

Thirty-four patients were included (mean age = 67.6 ± 11.2 years). Their clinical characteristics were collected, and they performed a 6MWT, in which the initial claudication distance (ICD) and total walking distance (TWD) were recorded. During and after the 6MWT, calf muscle oxygen saturation (StO₂) parameters were monitored continuously to measure microcirculation behavior. The association between calf muscle StO₂ parameters and walking impairment were analyzed by Pearson or Spearman correlations.

RESULTS

Walking impairment was not associated with any StO₂ parameters during exercise. In contrast, after 6MWT, recovery time of StO₂ (r = -0.472, P = 0.008) and recovery time to maximal StO₂ (r = -0.402, P = 0.019) were negatively correlated with ICD. Furthermore, the distance walked under claudication symptoms (ΔTWD-ICD) was positively correlated with recovery time to maximal StO₂ (r = 0.347, P = 0.048).

CONCLUSIONS

In symptomatic PAD patients, shorter ICD values during a 6MWT are associated with a delayed recovery in calf muscle StO₂ after exercise. Calf muscle StO₂ parameters decrease subtly during 6MWT, suggesting that the degree of ischemia in the calf muscle during ground walking, simulating efforts of the daily walking, is relatively low.

Decrease in pulmonary function and oxygenation after lung resection

Respiratory deficits are common following curative intent lung cancer surgery and may reduce the patient's ability to be physically active. We evaluated the influence of surgery on pulmonary function, respiratory muscle strength and physical performance after lung resection.

Pulmonary function, respiratory muscle strength (maximal inspiratory/expiratory pressure) and 6-min walk test (6MWT) were assessed pre-operatively, 2 weeks post-operatively and 6 months post-operatively in 80 patients (age 68±9 years).

Video-assisted thoracoscopic surgery was performed in 58% of cases. Two weeks post-operatively, we found a significant decline in pulmonary function (forced vital capacity −0.6±0.6 L and forced expiratory volume in 1 s −0.43±0.4 L; both p<0.0001), 6MWT (−37.6±74.8 m; p<0.0001) and oxygenation (−2.9±4.7 units; p<0.001), while maximal inspiratory and maximal expiratory pressure were unaffected. At 6 months post-operatively, pulmonary function and oxygenation remained significantly decreased (p<0.001), whereas 6MWT was recovered.

We conclude that lung resection has a significant short- and long-term impact on pulmonary function and oxygenation, but not on respiratory muscle strength. Future research should focus on mechanisms negatively influencing post-operative pulmonary function other than impaired respiratory muscle strength.

Lung resection has a significant short- and long-term impact on pulmonary function and oxygenation, but not on respiratory muscle strengthhttp://ow.ly/WTqc30h6j4i