The metabolic exercise test data combined with Cardiac and Kidney Indexes (MECKI) score and prognosis in heart failure. A validation study

BACKGROUND: The Metabolic Exercise test data combined with Cardiac and Kidney Indexes (MECKI) score is a prognostic model to identify heart failure (HF) patients at risk for cardiovascular mortality (CVM) and urgent heart transplantation (uHT) based on 6 routine clinical parameters: hemoglobin, sodium, kidney function by the Modification of Diet in Renal Disease (MDRD) equation, left ventricle ejection fraction (LVEF), percentage of predicted peak oxygen consumption (VO2) and VE/VCO2 slope. OBJECTIVES: MECKI score must be generalizable to be considered useful: therefore, its performance was validated in a new sequence of HF patients. METHODS: Both the development (MECKI-D) and the validation (MECKI-V) cohorts were composed of consecutive HF patients with LVEF <40% able to perform a symptom-limited cardiopulmonary exercise testing. The CVM or uHT rates were analyzed at one, two and three years in both cohorts: all patients with a censoring time shorter than the scheduled follow-up were excluded, while those with events occurring after 1, 2 and 3 years were considered as censored. RESULTS: MECKI-D and MECKI-V consisted of 2009 and 992 patients, respectively. MECKI-V patients had a higher LVEF, higher peak VO2 and lower VE/VCO2 slope, higher prescription of beta-blockers and device therapy: after the 3-year follow-up, CVM or uHT occurred in 206 (18%) MECKI-D and 44 (13%) MECKI-V patients (p<0.000), respectively. MECKI-V AUC values at one, two and three years were 0.81 ± 0.04, 0.76 ± 0.04, and 0.80 ± 0.03, respectively, not significantly different from MECKI-D. CONCLUSIONS: MECKI score preserves its predictive ability in a HF population at a lower risk.