Cardio-vascular reserve index (CVRI) during exercise complies with the pattern assumed by the cardiovascular reserve
Michael J Segel1, Ben-Zion Bobrovsky2, Itay E Gabbay3
1Lung Institute, Sheba Medical Center, Ramat-Gan, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
Insights
The Cardio-vascular reserve index (CVRI) decreases during exercise, reaching its lowest point at peak exertion, aligning with the cardiovascular reserve hypothesis. Recovery shows an increase in CVRI, varying with exercise capacity.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- The cardiovascular reserve hypothesis posits a quantifiable reserve in cardiovascular function.
- The Cardio-vascular reserve index (CVRI) has been empirically validated as an estimate of this reserve across various conditions.
Purpose of the Study:
- To evaluate if the Cardio-vascular reserve index (CVRI) during exercise aligns with predictions of the cardiovascular reserve hypothesis.
- To assess CVRI patterns at different stages of cardiopulmonary exercise testing (CPX).
Main Methods:
- Retrospective analysis of patient data from cardiopulmonary exercise testing (CPX).
- Physiological measurements were collected at rest, anaerobic threshold, peak exercise, and during recovery.
- CVRI was calculated retrospectively for each patient at these four stages.
Main Results:
- Mean CVRI was highest at rest (0.81) and significantly decreased with exercise, reaching a minimum at peak exercise (0.35).
- CVRI at peak exercise was similar across different exercise capacity groups (0.33-0.37).
- CVRI increased during recovery, with greater increases observed in individuals with higher exercise capacity.
Conclusions:
- Exercise-induced changes in CVRI follow the pattern predicted by the cardiovascular reserve hypothesis.
- The CVRI nadir at peak exercise suggests an exhaustion threshold that is consistent across varying exercise capacities.
- Further research is recommended to explore the clinical utility of CVRI.
Objectives:
The Cardio-vascular reserve index (CVRI) had been empirically validated in diverse morbidities as a quantitative estimate of the reserve assumed by the cardiovascular reserve hypothesis. This work evaluates whether CVRI during exercise complies with the cardiovascular reserve hypothesis.
Design:
Retrospective study based on a database of patients who underwent cardio-pulmonary exercise testing (CPX) for diverse indications.
Methods:
Patient's physiological measurements were retrieved at four predefined CPX stages (rest, anaerobic threshold, peak exercise and after 2min of recovery). CVRI was individually calculated retrospectively at each stage.
Results:
Mean CVRI at rest was 0.81, significantly higher (p<0.001) than at all other stages. CVRI decreased with exercise, reaching an average at peak exercise of 0.35, significant lower than at other stages (p<0.001) and very similar regardless of exercise capacity (mean CVRI 0.33-0.37 in 4 groups classified by exercise capacity, p>0.05). CVRI after 2min of recovery rose considerably, most in the group with the best exercise capacity and least in those with the lowest exercise capacity.
Conclusions:
CVRI during exercise fits the pattern predicted by the cardiovascular reserve hypothesis. CVRI decreased with exercise reaching a minimum at peak exercise and rising with recovery. The CVRI nadir at peak exercise, similar across groups classified by exercise capacity, complies with the assumed exhaustion threshold. The clinical utility of CVRI should be further evaluated.
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