Prognostic respiratory parameters in heart failure patients with and without exercise oscillatory ventilation - a systematic review and descriptive meta-analysis.

The purpose of this review was to describe the occurrence of prognostic variables as derived from cardiopulmonary exercise testing (CPET) in patients with heart failure (HF), presenting exercise oscillatory ventilation (EOV) compared to patients without EOV. The effect of EOV on peak oxygen consumption (VO2), minute ventilation/carbon dioxide production (VE/VCO2) slope, oxygen uptake efficiency slope (OUES), rest and peak pulmonary end-tidal carbon dioxide pressure (PETCO2) was meta-analysed. A systematic search strategy was performed in five databases (Pubmed, Cochrane Library, PEDro, Science Direct and Web of Science) assessing 252 articles for eligibility. Nineteen citations met the inclusion criteria totalling 3032 patients with HF (EOV=1111; non-EOV=1921). The risk of bias was assessed by two researchers. Extracted data were pooled using random or fixed effects meta-analysis, if appropriate. The level of significance was set at p≤0.05. Overall, the presentation of EOV significantly indicated aggravated prognostic markers. Subgroup analysis revealed left ventricular ejection fraction (LVEF) and mode of CPET protocol as independent factors, whereas defining EOV significantly influenced the results. A meta-analysis of studies reporting hazard ratios for cardiovascular events demonstrated that HF patients with EOV run a fourfold risk for an adverse event compared to HF patients without EOV. In general, these findings suggest that the presence of EOV in patients with HF is associated with a deterioration of the prognostic CPET parameters. Furthermore, EOV can occur in HF patients with reduced as well as preserved ejection fraction. Further research on defining and assessing EOV in a more accurate and reproducible way is required.