Isocapnic buffering period: From physiology to clinics. (July 2019)

• Record Type: Journal Article
• Authors: Carriere, Cosimo; Corrà, Ugo; Piepoli, Massimo; Bonomi, Alice; Salvioni, Elisabetta; Binno, Simone; Magini, Alessandra; Sciomer, Susanna; Pezzuto, Beatrice; Gentile, Piero; Schina, Mauro; Sinagra, Gianfranco; Agostoni, Piergiuseppe
• Is Part Of: European journal of preventive cardiology. Volume 26:Number 10(2019)
• Page Start: 1107
• Page End: 1114
• Publication Date: 2019-07
• Subjects: Heart failure -- isocapnic buffering period -- anaerobic threshold -- exercise; Cardiovascular system -- Diseases -- Prevention -- Periodicals; Cardiac patients -- Rehabilitation -- Periodicals; 616.12
• DOI: 10.1177/2047487319829950
• Languages: English
• ISSNs: 2047-4873

Abstract

Background: During cardiopulmonary exercise test, the isocapnic buffering period ranges between anaerobic threshold (AT) and respiratory compensation point (RCP). We investigated whether oxygen uptake (VO2 ) increase during the isocapnic buffering period (ΔVO2 AT-RCP) is related to heart failure severity and prognosis. Methods: We retrospectively analysed reduced ejection fraction heart failure patients who attained RCP at cardiopulmonary exercise test. The study endpoint was the composite of cardiovascular mortality and urgent heart transplantation/left ventricular assist device implantation. Hazard ratio was assessed to identify the increase of risk associated with ΔVO2 AT-RCP (below and above the median of ΔVO2 AT-RCP). Results: AT and RCP were both identified in 782 (39.2%) out of 1995 reduced ejection fraction heart failure cases. Left ventricular ejection fraction and peak VO2 were 33 ± 9% and 16.5 ± 4.5 mL/kg per min (61 ± 16% of predicted value), suggesting moderate heart failure. At five years, endpoint did not vary between patients below and above the median ΔVO2 AT-RCP (3.85 mL/min per kg (25–75th interquartile range = 2.69–5.46)). ΔVO2 AT-RCP correlated with several parameters associated to heart failure prognosis, such as peak VO2, VE/VCO2 slope, brain natriuretic peptide and left ventricular ejection fraction. The ΔVO2 AT-RCP value was associated with prognosis at univariate but not at multivariable analysis, where only VE/VCO2 slope endured. Conclusion: ΔVO2 AT-RCP correlates with several parameters linked to heart failure severity. Isocapnic buffering period stratifies heart failure patients, but not more than other prognostic indices.