Prognostic value of a new cardiopulmonary exercise testing parameter in chronic heart failure: oxygen uptake efficiency at peak exercise — comparison with oxygen uptake efficiency slope
Valor prognóstico de um novo parâmetro da prova de esforço cardiorrespiratória na insuficiência cardíaca crónica: a eficiência do consumo de oxigénio no pico de esforço — comparação com o declive da eficiência de consumo de oxigénio
Alexandra Toste??, , Rui Soares, Joana Feliciano, Valeska Andreozzi, Sofia Silva, Ana Abreu, Ruben Ramos, Ninel Santos, Lurdes Ferreira, Rui Cruz Ferreira
Serviço de Cardiologia, Hospital de Santa Marta, Lisboa, Portugal
Received 30 March 2010, Accepted 11 May 2011
Abstract
Introduction

A growing body of evidence shows the prognostic value of oxygen uptake efficiency slope (OUES), a cardiopulmonary exercise test (CPET) parameter derived from the logarithmic relationship between O2 consumption (VO2) and minute ventilation (VE) in patients with chronic heart failure (CHF).

Objective

To evaluate the prognostic value of a new CPET parameter — peak oxygen uptake efficiency (POUE) — and to compare it with OUES in patients with CHF.

Methods

We prospectively studied 206 consecutive patients with stable CHF due to dilated cardiomyopathy — 153 male, aged 53.3±13.0 years, 35.4% of ischemic etiology, left ventricular ejection fraction 27.7±8.0%, 81.1% in sinus rhythm, 97.1% receiving ACE-Is or ARBs, 78.2% beta-blockers and 60.2% spironolactone — who performed a first maximal symptom-limited treadmill CPET, using the modified Bruce protocol. In 33% of patients an cardioverterdefibrillator (ICD) or cardiac resynchronization therapy device (CRT-D) was implanted during follow-up.

Peak VO2, percentage of predicted peak VO2, VE/VCO2 slope, OUES and POUE were analyzed. OUES was calculated using the formula VO2 (l/min) = OUES (log10VE) + b. POUE was calculated as pVO2 (l/min) / log10peakVE (l/min). Correlation coefficients between the studied parameters were obtained. The prognosis of each variable adjusted for age was evaluated through Cox proportional hazard models and R2 percent (R2%) and V index (V6) were used as measures of the predictive accuracy of events of each of these variables. Receiver operating characteristic (ROC) curves from logistic regression models were used to determine the cut-offs for OUES and POUE.

Results

pVO2: 20.5±5.9; percentage of predicted peak VO2: 68.6±18.2; VE/VCO2 slope: 30.6±8.3; OUES: 1.85±0.61; POUE: 0.88±0.27. During a mean follow-up of 33.1±14.8 months, 45 (21.8%) patients died, 10 (4.9%) underwent urgent heart transplantation and in three patients (1.5%) a left ventricular assist device was implanted. All variables proved to be independent predictors of this combined event; however, VE/VCO2 slope was most strongly associated with events (HR 11.14). In this population, POUE was associated with a higher risk of events than OUES (HR 9.61 vs. 7.01), and was also a better predictor of events (R2: 28.91 vs. 22.37).

Conclusion

POUE was more strongly associated with death, urgent heart transplantation and implantation of a left ventricular assist device and proved to be a better predictor of events than OUES. These results suggest that this new parameter can increase the prognostic value of CPET in patients with CHF.

Resumo
Introdução

Vários estudos demonstraram que o declive da eficiência de consumo de O2 (DECO), derivado da relação logarítmica entre o consumo de O2 (VO2) e a ventilação minuto (VE) durante a prova de esforço cárdiorrespiratória (PECR), apresenta valor prognóstico independente de eventos em doentes (dts) com insuficiência cardíaca (IC) crónica.

Objectivos

Avaliar o valor prognóstico de um novo parâmetro da PECR, a eficiência do consumo de O2 no pico de esforço (ECOP) e compará-lo com o do DECO em dts com IC.

Métodos

Estudámos, prospectivamente, 206 dts com miocardiopatia dilatada e IC estável (153 do sexo masculino, 53,3±13,0 anos, 35,4% isquémica, fracção de ejecção do VE 27,7±8,0%, 81,1% em ritmo sinusal, 97,1% sob i-ECA e/ou ARAII, 78,2% sob bloqueadores beta, 60,2% sob espironolactona), que efectuaram uma primeira PECR (máxima limitada por sintomas, em tapete rolante, protocolo de Bruce modificado). Em 33% dos dts foi implantado um cardioversor-desfibrilhador (CDI) ou um sistema de ressíncronização cardíaca com CDI (CRT-D) durante o seguimento.

Analisámos o VO2 de pico, a percentagem do VO2 máximo teórico atingida, o declive VE/VCO2, o DECO e o ECOP. O DECO foi calculado através da fórmula VO2 (L/min) = DECO (log10VE) + b. O ECOP foi calculado como ECOP=VO2p (L/min) / log10VE máximo (L/min). Os coeficientes de correlação entre os parâmetros estudados foram calculados. O prognóstico de cada variável ajustado por idade foi avaliado através dos modelos proporcionais de Cox e o R2 percentual e o V index foram utilizados como medidas de acuidade preditiva de eventos de cada uma destas variáveis. Recorremos às curvas ROC dos modelos de regressão logística para determinar o cut-off de cada parâmetro.

Resultados

VO2p: 20,5±5,9; percentagem do VO2 máximo teórico atingida: 68,6±18,2; declive VE/VCO2: 30,6±8,3; DECO: 1,85±0,61; ECOP: 0,88±0,27. Num seguimento médio de 33,1±14,8 meses após a inclusão no estudo, faleceram 45 dts (21,8%), 10 (4,9%) foram submetidos a transplantação cardíaca urgente e em três dts (1,5%) foi implantado um sistema de assistência ventricular. Todos os parâmetros estudados foram preditores independentes deste evento combinado. No entanto, o declive VE/VCO2 foi o parâmetro mais associado a eventos (RR 11,14). O ECOP associou-se, nesta população, a um maior risco de eventos que o DECO (RR 9,61 versus 7,01), tendo-se revelado também um melhor preditor de eventos (R2: 28,91 versus 22,37).

Conclusão

O ECOP associou-se mais a probabilidade de morte, transplante cardíaco urgente e implantação de sistema de assistência ventricular e revelou-se um melhor preditor de eventos que o DECO. Os resultados obtidos sugerem que este novo parâmetro pode aumentar o valor prognóstico das PECR em doentes com IC.

Keywords
Heart failure, Exercise testing, Prognosis
Palavras-chave
Insuficiência cardíaca, Prova de esforço, Prognóstico
This article is only available in PDF
References
1.
R. Baba,M. Nagashima,M. Goto
Oxygen intake efficiency slope: a new index of cardiorespiratory functional reserve derived from the relationship between oxygen consumption and minute ventilation during incremental exercise
J Am Coll Cardiol, 28 (1996), pp. 1567-1572
2.
C. Van Laethem,J. Bartunek,M. Goethals
Oxygen uptake efficiency slope, a new submaximal parameter in evaluating exercise capacity in chronic heart failure patients
Am Heart J, 149 (2005), pp. 175-180 http://dx.doi.org/10.1016/j.ahj.2004.07.004
3.
A.T. McRae,J.B. Young,M.L. Alkotob
The oxygen uptake efficiency slope as a predictor of mortality in chronic heart failure
J Am Coll Cardiol, 39 (2002), pp. 183
4.
L.C. Davies,R. Wensel,P. Georgiadou
Enhanced prognostic value from cardiopulmonary exercise testing in chronic heart failure by non-linear analysis: oxygen uptake efficiency slope
Eur Heart J, 27 (2006), pp. 684-689 http://dx.doi.org/10.1093/eurheartj/ehi672
5.
J. Myers,R. Arena,F. Dewey
A cardiopulmonary exercise testing score for predicting outcomes in patients with heart failure
Am Heart J, 156 (2008), pp. 1177-1183 http://dx.doi.org/10.1016/j.ahj.2008.07.010
6.
R. Arena,J. Myers,J. Abella
The influence of body mass index on the oxygen uptake efficiency slope in patients with heart failure
Int J Cardiol, 125 (2008), pp. 270-272 http://dx.doi.org/10.1016/j.ijcard.2007.11.013
7.
R.J. Gibbons,G.J. Balady,J.W. Beasley
ACC/AHA Guidelines for exercise testing: a report of the American College of Cardiology/American Heart Association Task Force on Practical Guidelines (Committee on Exercise Testing)
J Am Coll Cardiol, 30 (1997), pp. 260-315
8.
K. Wasserman,J.E. Hansen,D.Y. Sue
Principles of exercise testing and interpretation
Lippincott, Williams & Wilkins, (2004)
9.
J.Y. Tabet,G. Thabut,P. Hainaut
Critical appraisal of the prognostic value of the VE/VCO2 slope in chronic heart failure
Eur J Heart Fail, 2 (2003), pp. 67
10.
R. Arena,J. Myers,S.S. Aslam
Prognostic comparison of the minute ventilation/carbon dioxide production ratio and slope in patients with heart failure
Heart Drug, 4 (2004), pp. 133-139
11.
R.L. Bard,B.W. Gillespie,N.S. Clarke
Determining the best ventilatory efficiency measure to predict mortality in patients with heart failure
J Heart Lung Transplant, 25 (2006), pp. 589-595 http://dx.doi.org/10.1016/j.healun.2005.11.448
12.
R. Arena,J. Myers,J. Abella
Development of a ventilatory classification system in patients with heart failure
Circulation, 115 (2007), pp. 2410-2417 http://dx.doi.org/10.1161/CIRCULATIONAHA.107.686576
13.
R. Arena,J. Myers,S.S. Aslam
Peak VO2 and VE/VCO2 slope in patients with heart failure: a prognostic comparison
Am H J, 147 (2004), pp. 354-360
14.
R. Arena,J. Myers,L. Hsu
The minute ventilation/carbon dioxide production slope is prognostically superior to the oxygen uptake efficiency slope
J Cardiac Fail, 13 (2007), pp. 462-469

( ! ) Warning: Invalid argument supplied for foreach() in /var/www/html/includes_ws/librerias/html/item.php on line 1203
Call Stack
#TimeMemoryFunctionLocation
10.0004243984{main}( ).../index.php:0
20.41383340816include( '/var/www/html/portugal/plantilla/central.php' ).../index.php:45
30.41473384304include( '/var/www/html/portugal/contenidos/item.php' ).../central.php:11
40.49723408592getAutorCorrespondenciaHTML( ).../item.php:281
Copyright © 2011. Sociedade Portuguesa de Cardiologia

Metrics

  • Impact Factor: 1,195(2016)
  • 5-years Impact Factor: 0,728
  • SCImago Journal Rank (SJR):0,29
  • Source Normalized Impact per Paper (SNIP):0,398