Heart failure prognosis over time: how the prognostic role of oxygen consumption and ventilatory efficiency during exercise has changed in the last 20 years

Aims: Exercise-derived parameters, specifically peak exercise oxygen uptake (peak VO 2 ) and minute ventilation/carbon dioxide relationship slope (VE/VCO 2 slope), have a pivotal prognostic value in heart failure (HF). It is unknown how the prognostic threshold of peak VO 2 and VE/VCO 2 slope has changed over the last 20 years in parallel with HF prognosis improvement. Methods and results: Data from 6083 HF patients (81% male, age 61 \ub1 13 years), enrolled in the MECKI score database between 1993 and 2015, were retrospectively analysed. By enrolment year, four groups were generated: group 1 1993\u20132000 (n = 440), group 2 2001\u20132005 (n = 1288), group 3 2006\u20132010 (n = 2368), and group 4 2011\u20132015 (n = 1987). We compared the 10-year survival of groups and analysed how the overall risk (cardiovascular death, urgent heart transplantation, or left ventricular assist device implantation) changed over time according to peak VO 2 and VE/VCO 2 slope and to major clinical and therapeutic variables. At 10 years, a progressively higher survival from group 1 to group 3 was observed, with no further improvement afterwards. A 20% risk for peak VO 2 15 mL/min/kg (95% confidence interval 16\u201313), 9 (11\u20138), 4 (4\u20132) and 5 (7\u20134) was observed in group 1, 2, 3, and 4, respectively, while the VE/VCO 2 slope value for a 20% risk was 32 (37\u201329), 47 (51\u201343), 59 (64\u201355), and 57 (63\u201352), respectively. Conclusions: Heart failure prognosis improved over time up to 2010 in a HF population followed by experienced centres. The peak VO 2 and VE/VCO 2 slope cut-offs identifying a definite risk progressively decreased and increased over time, respectively. The prognostic threshold of peak VO 2 and VE/VCO 2 slope must be updated whenever HF prognosis improves