Improved percent-predicted peak VO2 is associated with lower risk of hospitalization in patients with coronary heart disease. Analysis from the FRIEND registry

Quantifying assumptions underlying peak oxygen consumption equations across the body mass spectrum

The goal of this study is to quantify the assumptions associated with the Wasserman-Hansen (WH) and Fitness Registry and the Importance of Exercise: A National Database (FRIEND) predictive peak oxygen consumption (pVO2) equations across body mass index (BMI). Assumptions in pVO2 for both equations were first determined using a simulation and then evaluated using exercise data from the Stanford Exercise Testing registry. We calculated percent-predicted VO2 (ppVO2) values for both equations and compared them using the Bland-Altman method. Assumptions associated with pVO2 across BMI categories were quantified by comparing the slopes of age-adjusted VO2 ratios (pVO2/pre-exercise VO2) and ppVO2 values for different BMI categories. The simulation revealed lower predicted fitness among adults with obesity using the FRIEND equation compared to the WH equations. In the clinical cohort, we evaluated 2471 patients (56.9% male, 22% with BMI >30 kg/m2, pVO2 26.8 mlO2/kg/min). The Bland-Altman plot revealed an average relative difference of -1.7% (95% CI: -2.1 to -1.2%) between WH and FRIEND ppVO2 values with greater differences among those with obesity. Analysis of the VO2 ratio to ppVO2 slopes across the BMI spectrum confirmed the assumption of lower fitness in those with obesity, and this trend was more pronounced using the FRIEND equation. Peak VO2 estimations between the WH and FRIEND equations differed significantly among individuals with obesity. The FRIEND equation resulted in a greater attributable reduction in pVO2 associated with obesity relative to the WH equations. The outlined relationships between BMI and predicted VO2 may better inform the clinical interpretation of ppVO2 values during cardiopulmonary exercise test evaluations.

Effect of Adding a Program of Contextualized, Personalized, Remote Physical Activity Support to Conventional Cardiac Rehabilitation

PURPOSE

The objective of this investigation was to conduct a randomized controlled trial to evaluate whether KiActiv Heart alongside usual care (UC) promotes positive physical activity (PA) change versus UC alone.

METHODS

Patients in cardiac rehabilitation (n = 130) undertook an 8-wk intervention with follow-up at wk 8. Both groups attended UC and wore a PA monitor during the intervention. The intervention group accessed the digital service and received weekly one-to-one remote mentor sessions. The primary outcome was change in PA to achieve the Association of Certified Physiotherapists in Cardiac Rehabilitation (ACPICR) recommendations. The secondary outcome was cardiorespiratory fitness (CRF) change, measured using incremental shuttle walk test (ISWT).

RESULTS

The probability of meeting ACPICR "Daily Activity" recommendation was statistically significantly greater in the intervention group versus control at wk 8 ( P < .05). No statistically significant differences between groups were found for mean ISWT change (intervention 89 ± 116 m; control 44 ± 124 m).

CONCLUSION

Participation in KiActiv Heart alongside UC was associated with statistically significant improvement in probability of meeting ACPICR recommendation and non-statistically significant but potentially clinically important increases in CRF versus UC alone. This builds on existing evidence for effectiveness.

Early reduction in cardiorespiratory fitness and diastolic reserve following radiation therapy for lung cancer

BACKGROUND

Contemporary radiotherapy for the treatment of lung cancer is effective in targeting tumor tissue while limiting heart exposure, yet cardiac toxicity still occurs, often becoming clinically apparent years later. Cardiorespiratory fitness (CRF) is an independent predictor of cardiovascular, cancer-related, and overall mortality and may serve as a sensitive measure of subclinical cardiac toxicity following anti-cancer treatments. Prior work has demonstrated a significant relationship between reduced CRF and impaired left-ventricular (LV) diastolic reserve in cancer survivors following thoracic radiotherapy. The purpose of this study was to assess early longitudinal changes in CRF and cardiac function in patients with lung cancer following radiotherapy.

METHODS

Ten patients (69 [61-76] years, 70% female) with lung cancer without known cardiovascular disease scheduled to receive radiotherapy involving a clinically-relevant heart dose (≥ 5 Gy to > 10% of heart volume) were evaluated prior to and following treatment. Changes in CRF (peak oxygen consumption [VO2peak], oxygen uptake efficiency slope [OUES]), cardiac function (LV ejection fraction [LVEF], rest and exercise diastolic function [diastolic functional reserve index (DFRI)]), cardiac biomarkers (N-terminal pro-brain natriuretic peptide [NT-proBNP], high-sensitivity C-reactive protein [hsCRP]), and health-related quality of life (HRQOL; Functional Assessment of Cancer Therapy-General-7 [FACT-G7]) were measured.

RESULTS

The VO2peak was reduced at baseline (1.245 [0.882-1.605] L·min- 1; 70 [62-86] %-predicted) and significantly declined (1.095 [0.810-1.448] L·min- 1, P = 0.047; 62 [56-76] %-predicted, P = 0.005) at 6.0 [3.0-6.0] months post-radiotherapy. Similarly, a significant decline in the OUES was observed (1.63 [1.27-1.88] to 1.57 [1.12-1.75], P = 0.032). Systolic cardiac function was normal at baseline and did not change following radiotherapy (LVEF; 62 [56-65]% to 66 [57-68]%, P = 0.475). The DFRI significantly declined following radiotherapy (34.9 [22.7-41.6] vs. 12.8 [3.1-35.9]). The hsCRP increased significantly from 4.4 [1.4-5.8] to 6.1 [3.7-20.7] g/L, P = 0.047 with a trend towards higher levels of NT-proBNP (65 [49-125] to 121 [88-191] pg/mL, P = 0.110). Health-related quality of life significantly decreased (FACT-G7; 21.5 [18.8-25] to 15.5 [11.5-20]; P = 0.021) post-radiotherapy.

CONCLUSIONS

Patients with lung cancer receiving radiotherapy with a clinically-significant heart dose experience reductions in CRF (VO2peak, OUES) as early as six months following treatment with concurrent reductions in diastolic reserve (DFRI), HRQOL, and increases in cardiac biomarkers (NT-proBNP, hsCRP).

How to interpret a cardiorespiratory fitness assessment - Key measures that provide the best picture of health, disease status and prognosis

Graded exercise testing is a widely accepted tool for revealing cardiac ischemia and/or arrhythmias in clinical settings. Cardiopulmonary exercise testing (CPET) measures expired gases during a graded exercise test making it a versatile tool that helps reveal underlying physiologic abnormalities that are in many cases only present with exertion. It also characterizes one's health status and clinical trajectory, informs the therapeutic plan, evaluates the efficacy of therapy, and provides submaximal and maximal information that can be used to tailor an exercise intervention. Practitioners can also modify the mode and protocol to allow individuals of all ages, fitness levels, and most disease states to perform a CPET. When used to its full potential, CPET can be a key tool used to optimize care in primary and secondary prevention settings.

The association between cardiopulmonary exercise testing and postoperative outcomes in patients with lung cancer undergoing lung resection surgery: A systematic review and meta-analysis

BACKGROUND

Exercise capacity should be determined in all patients undergoing lung resection for lung cancer surgery and cardiopulmonary exercise testing (CPET) remains the gold standard. The purpose of this study was to investigate associations between preoperative CPET and postoperative outcomes in patients undergoing lung resection surgery for lung cancer through a review of the existing literature.

METHODS

A search was conducted on PubMed, Scopus, Cochrane Library and CINAHL from inception until December 2022. Studies investigating associations between preoperative CPET and postoperative outcomes were included. Risk of bias was assessed using the QUIPS tool. A random effect model meta-analysis was performed. I2 > 40% indicated a high level of heterogeneity.

RESULTS

Thirty-seven studies were included with 6450 patients. Twenty-eight studies had low risk of bias. [Formula: see text] peak is the oxygen consumption at peak exercise and serves as a marker of cardiopulmonary fitness. Higher estimates of [Formula: see text] peak, measured and as a percentagege of predicted, showed significant associations with a lower risk of mortality [MD: 3.66, 95% CI: 0.88; 6.43 and MD: 16.49, 95% CI: 6.92; 26.07] and fewer complications [MD: 2.06, 95% CI: 1.12; 3.00 and MD: 9.82, 95% CI: 5.88; 13.76]. Using a previously defined cutoff value of > 15mL/kg/min for [Formula: see text] peak, showed evidence of decreased odds of mortality [OR: 0.55, 95% CI: 0.28-0.81] and but not decreased odds of postoperative morbidity [OR: 0.82, 95% CI: 0.64-1.00]. There was no relationship between [Formula: see text] slope, which depicts ventilatory efficiency, with mortality [MD: -9.60, 95% CI: -27.74; 8.54] however, patients without postoperative complications had a lower preoperative [Formula: see text] [MD: -2.36, 95% CI: -3.01; -1.71]. Exercise load and anaerobic threshold did not correlate with morbidity or mortality. There was significant heterogeneity between studies.

CONCLUSIONS

Estimates of cardiopulmonary fitness as evidenced by higher [Formula: see text] peak, measured and as a percentage of predicted, were associated with decreased morbidity and mortality. A cutoff value of [Formula: see text] peak > 15mL/kg/min was consistent with improved survival but not with fewer complications. Ventilatory efficiency was associated with decreased postoperative morbidity but not with improved survival. The heterogeneity in literature could be remedied with large scale, prospective, blinded, standardised research to improve preoperative risk stratification in patients with lung cancer scheduled for lung resection surgery.

A Nonexercise Prediction of Peak Oxygen Uptake for Patients With Cardiovascular Disease: DATA FROM THE FITNESS REGISTRY AND THE IMPORTANCE OF EXERCISE INTERNATIONAL DATABASE (FRIEND)

PURPOSE

Nonexercise predictions of peak oxygen uptake (V˙ o2peak ) are used clinically, yet current equations were developed from cohorts of apparently healthy individuals and may not be applicable to individuals with cardiovascular disease (CVD). Our purpose was to develop a CVD-specific nonexercise prediction equation for V˙ o2peak .

METHODS

Participants were from the Fitness Registry and Importance of Exercise International Database (FRIEND) with a diagnosis of coronary artery bypass surgery (CABG), myocardial infarction (MI), percutaneous coronary intervention (PCI), or heart failure (HF) who met maximal effort criteria during a cardiopulmonary exercise test (n = 15 997; 83% male; age 63.1 ± 10.4 yr). The cohort was split into development (n = 12 798) and validation groups (n = 3199). The prediction equation was developed using regression analysis and compared with a previous equation developed on a healthy cohort.

RESULTS

Age, sex, height, weight, exercise mode, and CVD diagnosis were all significant predictors of V˙ o2peak . The regression equation was:V˙ o2peak (mL · kg -1 · min -1 ) = 16.18 - (0.22 × age [yr]) + (3.63 × sex [male = 1; female = 0]) + (0.14 × height [cm]) - (0.12 × weight [kg]) + (3.62 × mode [treadmill = 1; cycle = 0]) - (2.70 × CABG [yes = 1, no = 0]) - (0.31 × MI [yes = 1, no = 0]) + (0.37 × PCI [yes = 1, no = 0]) - (4.47 × HF [yes = 1, no = 0]). Adjusted R 2 = 0.43; SEE = 4.75 mL · kg -1 · min -1 .Compared with measured V˙ o2peak in the validation group, percent predicted V˙ o2peak was 141% for the healthy cohort equation and 100% for the CVD-specific equation.

CONCLUSIONS

The new equation for individuals with CVD had lower error between measured and predicted V˙ o2peak than the healthy cohort equation, suggesting population-specific equations are needed for predicting V˙ o2peak ; however, errors associated with nonexercise prediction equations suggest V˙ o2peak should be directly measured whenever feasible.

A new set of estimated cardiorespiratory fitness equations are associated with cognitive performance in older adults

This study aimed to develop new equations to estimate cardiorespiratory fitness specifically for older adults and, secondly, to analyze the associations of cardiorespiratory fitness, both objectively measured and estimated using new equations, with cognitive performance. Ninety-two older adults (41 females, 65-75 years) from baseline data of a randomized controlled trial were analyzed ("ClinicalTrials.gov" Identifier: NCT03923712). Participants completed 4 measurement sessions including (i) physiological and health indicators in a laboratory setting, (ii) field-based fitness tests, (iii) sociodemographic and physical activity questionnaires, and (iv) a battery of neuropsychological tests to evaluate cognitive performance. The main findings were as follows: (i) a set of new equations with good predictive value for estimated cardiorespiratory fitness were developed (74-87%), using different scenarios of complexity and/or equipment requirements, and (ii) higher estimated cardiorespiratory fitness, even using its simplest equation (eCRF =  - 1261.99 + 1.97 × 6 min walking test (m) + 1.12 × bioimpedance basal metabolic rate (kcal/day) + 5.25 × basal heart rate (bpm)), was associated with better cognitive performance evaluated by several neuropsychological tests (i.e., language, cognitive flexibility, fluency, attention, and working memory), similar to using objectively measured cardiorespiratory fitness. In summary, a new set of estimated cardiorespiratory fitness equations have been developed with predictive values ranging from 74 to 87% that could be used based on necessity, availability of equipment, resources, or measurement context. Moreover, similar to objectively measured cardiorespiratory fitness, this measure of estimated cardiorespiratory fitness was positively associated with performance on language, fluency, cognitive flexibility, attention, and working memory, independently of sex, age, and education level.

Promotion and maintenance of physically active lifestyle in older outpatients 2 years after acute coronary syndrome

AIMS

To examine long-term changes in lifestyle and exercise capacity of older patients hospitalized for acute coronary syndrome (ACS) involved in an innovative centre- and home-based exercise-based secondary prevention program.

METHODS

A sample of 118 patients with ACS (age 76 [72-80] years) was analysed. Long-term changes in self-reported weekly leisure-time physical activity (wLTPA), walking speed (WS), and estimated cardiorespiratory fitness (eCRF, VO₂peak, mL/kg/min) were the outcome variables. The program consisted of seven individual on-site sessions including motivational interviewing to reach exercise goals. Exercise prescription was based on the results of a standardized moderate and perceptually regulated treadmill walk to estimate VO₂peak. wLTPA, WS, and eCRF were assessed at 1 (baseline), 2, 3, 4, 6, 12, and 24 months after discharge.

RESULTS

87, 76, and 70 patients completed follow-up at 6, 12, and 24 months, respectively. wLTPA significantly increased during the follow-up period (median METs/H/week 2.5, 11.2, 12.0, and 13.4 at baseline, 6, 12, and 24 months, respectively; P < 0.0001). At baseline, 18% of the sample met the current international guidelines for physical activity, while 75%, 70%, and 76% of them met the recommended values at 6-, 12-, and 24-month follow-up sessions, respectively. These results were associated with increasing median WS (2.9 ± 1.0, 4.3 ± 1.2, 4.5 ± 1.1, 4.5 ± 1.2 km/h, respectively, P < 0.0001), and VO₂peak (16.5, 21.4, 21.1, 21.3 mL/kg/min, respectively, P < 0.0001).

CONCLUSIONS

This early, individualized exercise intervention improved long-term adherence to a physically active lifestyle, walking capacity, and eCRF in older patients after ACS. Larger studies are needed to confirm short- and long-term clinical benefits of this intervention.

Effect of different physical training modalities on peak oxygen consumptions in post-acute myocardial infarction patients: systematic review and meta-analysis

Physical training can increase peak oxygen uptake (VO2peak) in people who have suffered acute myocardial infarction (AMI). However, there is still a gap in the literature in relation to the effectiveness of different types of interventions. Therefore, the aim of the present study was to evaluate the effects of different physical training modalities on VO2peak in post-AMI patients. The following databases were used: PubMed (MEDLINE), Cochrane Library, Scopus, and Pedro. Studies that evaluated aerobic exercise, strength exercise, or combined exercise were included. Six studies met eligibility criteria. Aerobic exercise increased VO2peak by 6.07 ml.kg-1.min-1 when compared to the control group (CG) (p = 0.013). The comparison between combined exercise and control group detected a difference of 1.84 ml.kg-1.min-1, but this was not significant (p = 0.312). We therefore conclude that aerobic exercise is the only modality that is effective for increasing VO2peak compared to a control group.

The V˙E/V˙co2 Slope During Maximal Treadmill Cardiopulmonary Exercise Testing: REFERENCE STANDARDS FROM FRIEND (FITNESS REGISTRY AND THE IMPORTANCE OF EXERCISE: A NATIONAL DATABASE)

PURPOSE

Cardiopulmonary exercise testing (CPX) is the gold standard approach for the assessment of cardiorespiratory fitness (CRF). The primary aim of the current study was to determine reference standards for the minute ventilation/carbon dioxide production (V˙E/V˙co2) slope in a cohort from the "Fitness Registry and the Importance of Exercise: A National Database" (FRIEND) Registry.

METHODS

The current analysis included 2512 tests from 10 CPX laboratories in the United States. Inclusion criteria included CPX data on apparently healthy men and women: (1) age ≥20 yr; and (2) with a symptom-limited exercise test performed on a treadmill. Ventilation and V˙co2 data, from the initiation of exercise to peak, were used to calculate the V˙E/V˙co2 slope via least-squares linear regression. Reference values were determined for men and women by decade of life.

RESULTS

On average, V˙E/V˙co2 slope values were lower in men and increased with age independent of sex. Fiftieth percentile values increased from 27.1 in the second decade to 33.9 in the eighth decade in men and from 28.5 in the second decade to 33.7 in the eighth decade in women. In the overall group, correlations with baseline characteristics and the V˙E/V˙co2 slope were statistically significant (P < .05) although generally weak, particularly for age and body mass index.

CONCLUSION

The results of the current study establish reference values for the V˙E/V˙co2 slope when treadmill testing is performed, and all exercise data are used for the slope calculation. These results may prove useful in enhancing the interpretation of CPX results when assessing CRF.