Dynamic Analysis of Exercise Oxygen Consumption Predicts Outcomes in Advanced Heart Failure

Abstract

It is unclear whether cardiopulmonary stress testing provides prognostic information in patients with very advanced heart failure receiving contemporary medical therapy. Analysis of cardiopulmonary treadmill stress data in a group of patients with advanced heart failure and severe functional impairment was performed (N=102, peak exercise oxygen consumption [VO2] ≤14 mL/kg/min, 47% receiving β‐blockers). Dynamic variables (peak ‐ baseline values) better predicted outcomes than did single value peak measurements, especially ΔVO2. Multivariate analysis showed that usage of β‐blockers and ΔVO2 (both P<.05) independently and significantly predicted outcomes. Subgroup analysis showed that ΔVO2 was particularly useful in predicting outcomes in patients with ischemic cardiomyopathy or who were not receiving β‐blockers. Thus, in patients with very advanced heart failure, cardiopulmonary stress testing‐derived ΔVO2 provides important prognostic information useful to help predict clinical deterioration or death, particularly for patients with ischemic cardiomyopathy or who are not receiving β‐blockers.

Evaluation of NT-proBNP to predict outcomes in advanced heart failure

“…Which factor is most important will depend on the population being studied. For instance, in more advanced heart failure, peak VO 2 may not be as predictive compared with less sick patients (6), at least in part because the sickest patients are unable to exercise. Other factors such as haemodynamics (7), serum sodium (8) and circulating cytokines (9) have also been shown to be important.…”

Does permanent atrial fibrillation modify response to cardiac resynchronization therapy in heart failure patients?

“…In agreement with this, our AF patients had lower mean pre-CRT VO 2 max (probably related to older age, and also predicted VO 2 max) and more improved VO 2 max after CRT than SR. Also, HF patients with mean baseline VO 2 max <14 ml/kg/min, which was the case in our AF group, benefited most from the implantation of a CRT device. 39 The percentage of functional CPET responders was significantly higher in AF patients than in SR patients, for the reasons mentioned above. Despite these better values, post-CRT mean VO 2 max in AF did not exceed that in SR, and values at six months were similar in the two study groups.…”

“…39 Exercise capacity is objectively quantified by measurement of VO 2 max, carbon dioxide production (VCO 2 ), and minute ventilation. 40 Not surprisingly, VO 2 max has a strong linear correlation with both cardiac output and skeletal muscle blood flow.…”