Clinical, echocardiographic, and neurohormonal response to cardiac resynchronization therapy: are they interchangeable?

ABSTRACT

BACKGROUND: The relationship between changes in N-terminal pro-brain natriuretic peptide (NT-proBNP) and echocardiographic or clinical definitions of response to cardiac resynchronization therapy (CRT) has not been evaluated. The aims of the present evaluation were to assess (1) the relationship between changes in NT-proBNP after 6 months of CRT and clinical and echocardiographic responses; (2) the association between NT-proBNP changes and long-term outcome. METHODS: In 170 patients treated with CRT (age 61 ± 11 years, 75% male), clinical and echocardiographic parameters and circulating NT-proBNP levels were assessed at baseline and 6 months after CRT. At 6 months follow-up, improvement in New York Heart Association class ≥ 1 point, decrease in left ventricular end-systolic volume ≥ 15%, and decrease in NT-proBNP ≥ 15% defined clinical, echocardiographic, and neurohormonal CRT response, respectively. All-cause mortality data were collected and related to neurohormonal response. RESULTS: Neurohormonal, echocardiographic, and clinical response rates were 54%, 58%, and 66%, respectively. The majority of patients (71%) showing echocardiographic response had NT-proBNP reduction ≥ 15%. In contrast, only 58% of patients who showed clinical response also had NT-proBNP reduction ≥ 15%. During a median follow-up of 32 months, 40 patients died. Patients with neurohormonal response demonstrated a superior long-term outcome compared to patients without neurohormonal response (log-rank P = 0.02). CONCLUSIONS: NT-proBNP reduction ≥ 15% showed better agreement with echocardiographic response compared to clinical response. Neurohormonal response was associated with superior long-term outcome compared to insufficient reduction in NT-proBNP levels.