Clinical Recommendations for Cardiopulmonary Exercise Testing Data Assessment in Specific Patient Populations
The following are 10 points to remember about this scientific statement:
1. Cardiopulmonary exercise testing (CPX) by treadmill or bicycle has generally been limited to specialized centers. But with the availability of rapid response analyzers and computer-assisted data processing, there is an increasing appreciation of the value for clinical practice.
2. CPX includes the combination of standard graded exercise testing (GXT) with serial electrocardiograms (ECGs), hemodynamics, oxygen saturation, and subjective symptoms and measurement of ventilation and expired concentrations of oxygen (O2) and carbon dioxide (CO2).
3. Compared to the GXT, CPX is a superior method to: (a) accurately quantify cardiorespiratory fitness (CRF), (b) help identify the exercise-limiting pathophysiological mechanism(s) (e.g., cardiovascular, pulmonary, and musculoskeletal disease/disorders), and (c) prognostic stratification.
4. The most important variables measured during CPX are aerobic capacity, defined as peak VO2, peak VCO2, and the peak respiratory exchange ratio (RER). Peak VO2 is influenced by central (cardiac and pulmonary) and peripheral or skeletal muscle function (mitochondrial).
5. Abnormal peak VO2 reflects disease severity in congestive heart failure (CHF), hypertrophic cardiomyopathy (HCM), pulmonary arterial hypertension (PAH), chronic obstructive pulmonary disease (COPD), and interstitial lung disease (ILD). Normal range of 15-80 ml 02/kg/min is usually reported as a percent predicted based on norms for age and gender.
6. Peak RER, defined as the peak VCO2/VO2 ratio, reflects exercise effort. A value of ≥1.10 is consistent with an excellent exercise effort.
7. The peak or maximal minute ventilation (VE)/VCO2 slope represents the matching of ventilation and perfusion within the pulmonary system. Values <30 are considered normal. Abnormal values correlate with disease severity in systolic CHF, HCM, PAH, COPD, and ILD. When assessing prognosis in systolic heart failure, a VE/VCO2 slope ≥45 and a peak VO2 <10.0 ml O2/kg/min are indicative of a particularly poor prognosis over the next 4 years.
8. Normal VE in L/min is linear with continuous increase. In systolic and diastolic heart failure as well as congenital heart disease, there is often an excise oscillatory ventilation pattern with peaks and valleys, which is associated with a poor prognosis.
9. Cutaneous pulse oximetry (SpO2) should be monitored continuously, and normally is ≥95% at rest and should not decrease by >5% (absolute value). Desaturation is common in COPD, ILD, and PAH with increasing disease severity.
10. When using the CPX for differentiating cardiac from pulmonary causes of dyspnea, pulmonary function tests should be performed prior to and following to determine the forced expiratory volume (FEV)1 and peak expiratory flow. A post-exercise decrease in FEV1 >15% is consistent with exercise-induced bronchospasm.
This excellent review and statement will be very helpful for cardiologists and trainees evaluating dyspnea, mitochondrial myopathy, HCM, heart failure, and pulmonary hypertension.
Keywords: Lung Diseases, Interstitial, Oximetry, Mitochondrial Myopathies, Cardiomyopathy, Hypertrophic, Hypertension, Pulmonary, Heart Failure, Electrocardiography, Dyspnea, Exercise Test
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