Combining blood flow and tissue Doppler imaging with N-terminal pro-type B natriuretic peptide for risk stratification of clinically stable patients with systolic heart failure

This study was designed to ascertain whether the combination of Doppler assessment of the ratio of mitral blood flow to myocardial early diastolic velocities (E/E-m ratio) and plasma N-terminal pro-type B natriuretic peptide (NT-proBNP) testing is useful to better stratify patients with stable systolic heart failure (HF). A total of 362 outpatients with chronic systolic HF (left ventricular ejection fraction < 45%) underwent clinical assessment, NT-proBNP testing, and comprehensive echo-Doppler study. The endpoint was all-cause mortality or HF-related hospital admissions (i.e. hospitalization for worsening HF, biventricular pacemaker implantation, or mitral valve surgery). Median follow-up duration was 25 months. Two hundred and fifty-nine patients were judged clinically stable by a Framingham's criteria-based HF score. In multivariate Cox's proportional hazards analysis, plasma NT-proBNP (P < 0.0001) and E/E-m ratio (P= 0.04) were among the significant predictors of the combined endpoint. Survival free from cardiac mortality and HF-related hospitalization was 55% in patients with the E/E-m ratio in the higher third (>= 12), 77% in those with the E/E-m ratio in the intermediate third, and 86% in those with the E/E-m ratio in the lower third (< 7) (P < 0.0001). By stratifying patients according to NT-proBNP above the median, patients' outcome was predicted in 13 out of 17 in the intermediate third (P = 0.002) and in 9 out of 10 in the lower third of E/E-m ratio (P= 0.005). In patients with stable HF categorized according to the E/E-m ratio, NT-proBNP testing improves risk stratification, particularly in those with minor degrees of diastolic dysfunction.