ABC | Volume 114, Nº2, February 2020

Short Editorial Mendes CPET in the evaluation for heart transplant Arq Bras Cardiol. 2020; 114(2):219-221 resynchronization device following the COMPANION study and recommended using the prognostic scores [Heart Failure Survival Score (HFSS) and Seattle Heart Failure Model (SHFM)] together with the CPET parameters (class IIb, LE B). Regarding the pVO 2 , it maintained the cutoff points pVO 2  ≤ 12 (under BB therapy) and ≤ 14 mL/Kg/min (intolerant to BB therapy) as class I (LE B) recommendations. It considers reasonable to use as a cutoff point a pVO 2 value < 50% of the maximum predicted in patients under the age of 50 years and in females, assigning it a IIa classification, LE B. It recommends using the criterion VE/VCO 2 slope > 35 only in cases of submaximal CPET, i.e., when the respiratory exchange ratio (RER) is < 1.05 at peak effort (class IIb, LE C). Guazzi et al. 6 in 2012 considered that mortality would be > 50%, between 1 and 4 years, if the criteria VE/VCO 2 slope ≥45, pVO 2 <10.0mL/Kg/min, and ventilatory oscillations (VO), 7 the expired CO 2 pressure (P ET CO 2 ) < 33 mmHg at rest and with an increase of less than 3mmHg during exercise were present. In addition to the recommendation of using stricter criteria in pVO 2 and especially in the VE/VCO 2 slope, Guazzi et al. 6 introduced two new parameters in the assessment: the oscillatory breathing (OB) and P ET CO 2 . Before this publication, other authors, including Ferreira et al., 8 defined higher cutoff points for the VE/VCO 2 slope. In this article, a cutoff point of 43 was defined, which is much stricter and more discriminative than the ISHLT criterion. In 2016, Malhotra et al. 9 demonstrated that patients with HFREF with pVO 2 < 12 or 14 mL/Kg/min (with or without BB), VE/VCO 2 slope > 36, OB, oxygen uptake efficiency below 1.4, reaching systolic pressure value < 120 mmHg, with a heart rate decrease below 6 bpm from peak effort for the 1 st minute of recovery, had a mortality rate > 20% at 1 year. In line with these articles, Wagner et al., 10 reviewed the recommendations in the light of current evidence and classified pVO 2 , its percentage in relation to the maximum predicted pVO 2 and the VE/CO 2 slope as class I (LE A) recommendations, and the presence of OB as IIa (LE B) and OUES and P ET CO 2 as IIb recommendations (LE B). Cardiac transplant indication: based on CPET and risk scores The final decision to place a patient without contraindications on the HT waiting list is based on a risk-benefit analysis of the different therapeutic options, based on a clinical, psychological and social assessment, and of parameters provided by the complementary tests. The CPET parameters can be considered separately or incorporated to scores such as HFSS and MECKI. The HFSS has seven variables, including pVO 2 . The MECKI, in turn, gives a higher weight to the CPET data when incorporated to the VE/VCO 2 slope and the percentage of the maximum expected VO 2 among its 5 variables. Freitas et al. 11 recently published an article comparing the value of 4 scores – HFSS, MECKI and two scores that integrate clinical parameters data: SHFM (10 variables) and MAGGIC (13 variables) – and MECKI was the most discriminative for CD or HT in the first year, with an area under the curve of 0.87. Conclusion The CPET is indicated for risk stratification in HFREF, particularly in the assessment of candidates for HT and ventricular assistance, aiming to objectively quantify functional limitation and provide relevant clinical information on the etiology of functional limitations that may have a cardiac, pulmonary or mixed cause. 9 It is not possible to perform CPET in patients in INTERMACS classes 1 to 3 (cardiogenic shock, receiving inotropic drugs or under circulatory assistance), in the presence of uncontrolled supraventricular or ventricular arrhythmias and in patients unable to exercise due to orthopedic pathology or extreme frailty. However, in most patients in INTERMACS classes 4 to 7, provided that an exercise protocol adapted to the patient's functional capacity or an ergometer that allows minimizing their orthopedic limitations is selected, it is possible to perform a maximum CPET and obtain parameters with high prognostic value in most patients with HFREF. Currently, pVO 2 , maximum predicted pVO 2 /VO 2 , VE/VCO 2 slope and OB are considered as the parameters provided by the CPET with the highest prognostic value in HFREF. 9 The CPET is still little used in Cardiology in the context of HF because its performance and interpretation involve some complexity, and because it has a higher cost than the conventional exercise test. However, it is of great interest as it allows an integrated assessment of the pathophysiology of the circulatory, respiratory and locomotor systems, making it possible to objectively identify the patients’ limitations, their cause, and stratify them in terms of prognosis. 1. Gonçalves AV, Pereira-da-Silva T, Soares R, Feliciano J, Moreira RI, Rio P et al. Previsão prognóstica dos parâmetros do teste de esforço cardiopulmonar empacientes com insuficiência cardíaca e fibrilação atrial. Arq Bras Cardiol. 2020; 114(2):209-218. 2. Mehra MR, Canter CE, Hannan MM,Semigran MJ, Uber PA, Baran DA, et al. The 2016 International Society for Heart and Lung Transplantation listing criteria for heart transplantation: A 10-year update. J Heart Lung Transplant. 2016; 35(1):1-23. 3. Wang TJ, LarsonMG, Levy D, Vasan RS, Leip EP, Wolf PA. Temporal relations of atrial fibrillation and congestive heart failure and their joint influence on mortality: The Framinghamheart study. Circulation. 2003; 107(23):2920-5. 4. Del Buono MG, Arena R, Borlaug BA, Carbone S, Canada JM, Kirkman DL. Exercise intolerance in patients with heart failure: JACC state-of-the-art review. J Am Coll Cardiol. 2019; 73(17):2209-25. 5. Keteyian SJ, Patel M, Kraus WE, Brawner CA, Mc Connell TR, Pina IL. Variables measured during cardiopulmonary exercise testing as predictors mortality in chronic systolic heart failure. J Am Coll Cardiol. 2016; 67(7):780-9. 6. Guazzi M, Adams V, Conraads V, Halle M, Mezzani A, Vanhees L, et al. 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