Background: Detection of heart failure (HF) in stable outpatients can be difficult until an overt event occurs. This study sought to determine whether the combination of B-type natriuretic peptide (BNP) and impedance cardiography (ICG) could be used in a nonacute clinical setting to risk stratify and predict HF-related events in stable outpatients.
Methods and results: Patients undergoing routine outpatient echocardiography underwent ICG and BNP testing and were followed for one year for HF-related events (Emergency Department [ED] visit or hospitalization due to HF or all-cause death). A total of 524 patients were analyzed, resulting in 57 HF-related events; 16 ED visits, 17 hospitalizations, and 24 all-cause deaths. Using Cox regression analyses, BNP and systolic time ratio index (STRI) by ICG proved to be the strongest predictors of future HF-related events. Patients with a BNP >100 pg/ml and STRI >0.45 sec(-1) had a significantly lower event-free survival rate than those with a high BNP and low STRI (67% versus 89%, P=.001). In patients with LV dysfunction only, if both BNP and STRI values were high, the relative risk of a HF-related event increased by 12.5 (95 % C.I. 4.2-36.7), when compared with patients with a low BNP and low STRI (P<.001).
Conclusions: In a nonacute clinical setting, both BNP and ICG testing can provide unique predictive power of long-term HF-related events in a stable cohort of patients with and without LV dysfunction.