Functional assessment based on cardiopulmonary exercise testing in mild heart failure: A multicentre study

Abstract

AimsIn this multicentre study, we compared cardio-pulmonary exercise test (CPET) parameters between heart failure (HF) patients classified as New York Heart Association (NYHA) class I and II to assess NYHA performance and prognostic role in mild HF. Methods and resultsWe included consecutive HF patients in NYHA class I or II who underwent CPET in three Brazilian centres. We analysed the overlap between kernel density estimations for the per cent-predicted peak oxygen consumption (VO 2 ), minute ventilation/carbon dioxide production (VE/VCO 2 ) slope, and oxygen uptake efficiency slope (OUES) by NYHA class. Area under the receiver-operating characteristic curve (AUC) was used to assess the capacity of per cent-predicted peak VO 2 to discriminate between NYHA class I and II. For prognostication, time to all-cause death was used to produce Kaplan-Meier estimates. Of 688 patients included in this study, 42% were classified as NYHA I and 58% as NYHA II, 55% were men, and mean age was 56 years. Median global per cent-predicted peak VO 2 was 66.8% (IQR 56-80), VE/VCO 2 slope was 36.9 (31.6-43.3), and mean OUES was 1.51 (±0.59). Kernel density overlap between NYHA class I and II was 86% for per cent-predicted peak VO 2 , 89% for VE/VCO 2 slope, and 84% for OUES. Receiving-operating curve analysis showed a significant, albeit limited performance of per cent-predicted peak VO 2 alone to discriminate between NYHA class I vs. II (AUC 0.55, 95% CI 0.51-0.59, P = 0.005). Model accuracy for probability of being classified as NYHA class I (vs. NYHA class II) across the spectrum of the per cent-predicted peak VO 2 was limited, with an absolute probability increment of 13% when per cent-predicted peak VO 2 increased from 50% to 100%. Overall mortality in NYHA class I and II was not significantly different (P = 0.41), whereas NYHA class III patients displayed a distinctively higher death rate (P < 0.001). Conclusions Patients with chronic HF classified as NYHA I overlapped substantially with those classified as NYHA II in objective physiological measures and prognosis. NYHA classification may represent a poor discriminator of cardiopulmonary capacity in patients with mild HF.

NYHA classification for decision‐making in heart failure: Time to reassess?

“…17 In a study comparing NYHA with objective cardiopulmonary exercise test measures -allegedly the gold standard in functional assessment -, the overlap between patients in NYHA classes I and II for the percent-predicted peak oxygen consumption and for the minute ventilation/carbon dioxide production slope was higher than 80%. 18 These results suggest that group-level differences between both categories may not apply to individual HF patients, and that NYHA is a poor surrogate of functional capacity particularly in mild HF.…”

“…In a secondary analysis of an RCT, participants in NYHA class I and II presented considerable overlap in objective markers of symptoms and physical capacity, such as a dyspnea visual analogue scale (60% kernel density overlap) and 6‐min walk test (64% overlap) 17 . In a study comparing NYHA with objective cardiopulmonary exercise test measures – allegedly the gold standard in functional assessment –, the overlap between patients in NYHA classes I and II for the percent‐predicted peak oxygen consumption and for the minute ventilation/carbon dioxide production slope was higher than 80% 18 . These results suggest that group‐level differences between both categories may not apply to individual HF patients, and that NYHA is a poor surrogate of functional capacity particularly in mild HF.…”

Papel Incremental da Classificação da New York Heart Association e dos Índices do Teste de Exercício Cardiopulmonar para Prognóstico na Insuficiência Cardíaca: um Estudo de Coorte

“…CPET methodology has been previously reported by our institution, 22 and it follows previously validated recommendations. 23 CPET was conducted by experienced and trained cardiologists using standardized institutional protocols.…”

“…A metodologia do TECP foi previamente relatada por nossa instituição 22 e segue recomendações previamente validadas. 23 O TECP foi realizado por cardiologistas experientes e treinados, utilizando protocolos institucionais padronizados.…”

Possibilities of Predicting Peak Oxygen Consumption in Patients With Chronic Heart Failure According to the 6‑Minute Walk Test

“…Особое место занимает роль оценки функционального состояния для определения прогноза у пациентов с начальной стадией СН и при СНсФВ. Показано, что у пациентов с легкой ХСН классификация NYHA недостоверно оценивала функциональные нарушения и плохо пронозировала смертность [19]. У пациентов с СНсФВ при анализе 5-летней выживаемости в моделях, скорректированных по возрасту, полу и терапии бета-адреноблокаторами, процент от должного VO 2 пик являлся наиболее сильным предиктором смерти и трансплантаций сердца (Wald χ 2 = 15,0; относительный риск -ОР на каждые 10 %; P<0,001) [20].…”