Author + information
- Alberto Dominguez-Rodriguez, MD, PhD∗ ( and )
- Pedro Abreu-Gonzalez, PhD
- ↵∗Hospital Universitario de Canarias, Department of Cardiology, Ofra s/n La Cuesta, E-38320, Tenerife, Spain
We read with interest the review by Ferreira et al. (1) about the use of clinically meaningful endpoints in heart failure (HF) trials, such as natriuretic peptides, the 6-min walking distance (6MWD) test, and quality of life. However, we would like to point out an important aspect in relationship to cardiopulmonary exercise testing (CPX) in the diagnostic workup of HF patients.
Basically, 2 methods for defining the extent of exercise limitation, the 6MWD (2) and CPX tests (3) are currently used in daily clinical practice. The 2 testing modalities are consistently different. The 6MWD test is a measure of distance, which is considered submaximal and perhaps more closely approximates the capacity to perform activities of daily living. Its clinical appeal also lies in the fact that it can be performed by almost all patients without the need for sophisticated equipment. Nonetheless, it does not allow for a thorough investigation of the pathogenetic mechanisms involved in dyspnea and fatigue sensation (2). The CPX test requires a maximal effort and provides a direct measurement of oxygen consumption along with a series of measured and derived respiratory variables with a robust body of evidence supporting its prognostic ability (3).
Cardiopulmonary exercise testing is used to noninvasively identify impaired aerobic capacity and anaerobic threshold in patients with HF and reduced ejection fraction, which in turn provides important information regarding the patients’ functional capacity and severity of the underlying HF. It has been featured in numerous clinical trials as a means of measuring drug or device efficacy and is widely used clinically as a measurement to help guide decisions regarding the suitability of patients for heart transplantation (3). The question is whether this additional evidence may restrain clinicians from performing a CPX test better than a 6MWD test, obviously opting for cost effectiveness and avoiding some complexity related to a CPX test.
Please note: Both authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2017 American College of Cardiology Foundation
- Ferreira J.P.,
- Duarte K.,
- Graves T.L.,
- et al.
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