The incremental prognostic importance of body fat adjusted peak oxygen consumption in chronic heart failure

Abstract

The adjustment of PkVO2 to lean body mass increases the prognostic value of cardiopulmonary stress testing in the evaluation of patients with chronic heart failure. The use of <19 ml O2/kg of lean body mass/min as a cutoff in PkVO2 should be used for timing transplantation, particularly in women and the obese.

The current standard measure of cardiorespiratory fitness introduces confounding by body mass: the DR's EXTRA study

“…21 Estimating fitness, independent from obesity, has been shown to improve the accuracy of fitness as a predictor of cardiac function. 22 Further studies are necessary to show whether dividing VO 2max by fat-free mass, rather than by total body mass, can avoid the bias against obese individuals that is illustrated in our results. To our knowledge, this is the largest population-based sample with objectively measured VO 2max and glucose tolerance in the literature.…”

The Obesity Paradox and Discrepancy Between Peak Oxygen Consumption and Heart Failure Prognosis—It's All in the Fat

“…[13][14][15] In addition, CPX may lose prognostic power in certain subgroups with high percentage of body fat, such as women and obese patients, especially in the era of β-blockers. 13,[15][16][17] We have demonstrated that adjusted exercise indices (including peak VO 2 and peak O 2 pulse) all predict prognosis better than nonadjusted indices ( Figure 1 and Figure 2). 16,17 This information may be particularly applicable to the favorable prognosis in obese patients with HF and women with higher levels of body fat.…”

“…[12][13][14][15] However, this parameter is generally corrected for total weight (as opposed to lean weight), despite the fact that fat is not aerobically active. 13,[15][16][17] We present a case to illustrate important concepts regarding the obesity paradox.…”

“…As the treatment modalities in chronic systolic HF become more complex and diverse, and especially with the number of candidates for HT increasing, it becomes increasingly important to identify individuals with the poorest prognoses. [13][14][15][16][17] Initially, Mancini et al 12 recommended peak VO 2 of 14 mL/kg/min as a cutoff value for risk stratification and as a discriminator for those being considered for HT. Clearly, patients with peak VO 2 >18 mL/kg/min have a very good prognosis, and those with values <10 mL/kg/min have a poor prognosis, but in between these extremes, the CPX may not be as valuable.…”

“…However, his peak VO 2 corrected for lean body mass, peak O 2 pulse, and especially peak O 2 pulse lean all suggest a more favorable prognosis, which may be especially applicable in this era of β-blockers. 13,[15][16][17] Obesity and HF Prognosis. Obesity is a problem reaching epidemic proportions in Westernized society with nearly 70% of adults classified as overweight or obese compared with fewer than 25% just 40 years ago.…”