Usefulness of 6-minute walk test, plasma neurohumoral and cytokine activation in the assessment of symptomatic patients with left ventricle dysfunction caused by chronic severe mitral valve regurgitation

Abstract

Objective — The aim of our study was to select the most relevant markers of impaired left ventricle (LV) function in patients with heart failure (HF) symptoms due to severe chronic mitral regurgitation (MR).

Methods and results—Thirty-six patients with decompensated HF due to severe MR underwent echocardiography, 6-minute walk test (6MWT) and measurements of plasma renin activity, angiotensin II, aldosterone, noradrenaline (NA), brain natriuretic peptide (BNP), tumour necrosis factor a (TNFa) with its receptors, and interleukine-6.

Patients presented with significant neurohumoral/cytokine activation. By stepwise multiple regression analysis the strongest prediction model for 6MWT included LVEDVI (R2 = 0.95, P = 0.024), BNP (R2 = 0.67, P = 0.0006), IL-6 (R2 = 0.90, P = 0.044); for BNP: 6MWT (R2 = 0.36, P = 0.003), LA (R2 = 0.56, P = 0.0077), LVESVI (R2 = 0.83, P = 0.0072); for NA : EF (R2 = 0.41, P = 0.036), and for TNFa: LVESVI (R2 = 0.65, P = 0.003).

Conclusions — 6MWT and neurohumoral markers (mainly BNP, but also NA and TNFa) are good predictors of the degree of LV remodelling, showing an independent correlation with the level of LV dilatation/dysfunction in chronic severe MR.These assessments may supplement standard echocardiography in LV decompensation due to severe MR.

Key Words:

• Chronic mitral regurgitation
• 6-minute walk test
• neurohormones
• cytokines