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Background: NT-pro-BNP level is increased in both systolic and diastolic heart failure (HF) and furthermore increases more during exercise. In diastolic HF, NT-pro-BNP might increase more during isometric exercise than during isotonic exercises because of increased afterload. We studied NT-pro-BNP values during isometric (handgrip) and isotonic (cycloergometer) exercise in HF patients with preserved left ventricular ejection fraction and different degrees of diastolic dysfunction.
Methods: We studied 87 patients, aged 58 ± 7.9 years, 42.6% females, with heart failure with LVEF > 40% and diastolic dysfunction. The patients were randomly distributed in two groups: 43 patients (Group I) and 44 patients (Group II). Group I underwent ramp exercise testing on a cycloergometer. Group II performed an isometric handgrip test. Plasma NT-pro-BNP levels were measured at rest and immediately after exercise.
Results: An abnormal relaxation (AR) pattern was recorded in 30 patients of Group I and 31 patients of Group II. Pseudonormalisation (PSN) and restrictive (R) pattern were noted in 13 patients of each group. As concerns Group I, NT-pro-BNP levels were increased in all patients, particularly in those with PSN or R pattern (p < 0.05). During exercise NT-pro-BNP decreases significantly in AR (1033 ± 516.63 to 800.51 ± 675.89 pg/mL) but not in PSN or R patients (1656.75 ± 977.48 to 1486.38 ± 1182.51 pg/mL). For Group II, NT-pro-BNP registered a similar increase as in Group I, with maximal values in PSN or R subgroup as compared to abnormal relaxation (p < 0.05). At peak exercise, NT-pro-BNP was practically unchanged as compared to the rest values for the whole group (-6%) and for the two subgroups (AR -6.7% and PSN or R -5.21%). We compared rest and exercise NT-pro-BNP with E/E’ ratio > 12 in order to identify increased diastolic filling pressure in the LV; AUC was 0.70 and 0.66 for rest and exercise NT-pro-BNP in case of isotonic testing and 0.74 and 0.72 in case of isometric exercise.
Conclusions: Our data suggest that in HF patients with preserved left ventricular ejection fraction, moderate isotonic and isometric exercises do not determine a significant increase (isometric exercise) or even decrease (isotonic exercise) in the value of NT-pro-BNP.
DOI: 10.7754/Clin.Lab.2014.140417
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