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A comparison of methods for determining the ventilatory threshold: implications for surgical risk stratification
Baruch Vainshelboim1, Shravan Rao2, Khin Chan2
1Division of Cardiology, Veterans Affairs Palo Alto Health Care System/Stanford University, 111C, 3801 Miranda Ave, Palo Alto, CA, 94304, USA. baruch.v1981@gmail.com.
Summary
Determining the ventilatory threshold (VT) for surgical risk assessment varies significantly between methods, impacting patient outcomes. Meticulous VT evaluation is crucial for accurate perioperative risk stratification.
Area of Science:
- Cardiopulmonary exercise testing
- Physiological markers
- Aerobic endurance capacity
Background:
- The ventilatory threshold (VT) is a key indicator of aerobic endurance and prognostic value in preoperative settings.
- Accurate VT determination is essential for surgical risk assessment but faces physiological and methodological challenges.
- Variability in VT measurement can complicate the evaluation of perioperative risk.
Purpose of the Study:
- To compare different methods for determining the ventilatory threshold (VT).
- To evaluate the implications of these methods for assessing perioperative risk in patients undergoing surgery.
Main Methods:
- Analysis of 445 treadmill cardiopulmonary exercise tests from 140 presurgical candidates with abdominal aortic aneurysms.
- Comparison of three VT determination methods: self-detected metabolic system (MS), expert visual (V) readings, and software log-log transformation (LLT).
- Statistical assessment using ANOVA, coefficient of variation (CV), limits of agreement (LoA), and interclass correlation coefficients (ICC).
Main Results:
- Significant differences in VT values were found between the MS, V, and LLT methods (P < 0.001).
- High interclass correlation (ICC = 0.85) was observed, but typical error and LoA indicated substantial variability.
- Coefficient of variation ranged from 15.9% to 19.6%, highlighting method-dependent discrepancies.
Conclusions:
- Clinically significant variations exist between different VT determination methods.
- These discrepancies pose challenges for accurate perioperative risk stratification.
- Emphasizes the need for careful VT evaluation and suggests future research into combined computational and expert review models for prognostic utility.