B-type natriuretic peptide levels predict functional capacity in postcardiac surgery patients

Area of Science:

• Cardiology
• Clinical Medicine
• Exercise Physiology

Background:

• Plasma B-type natriuretic peptide (BNP) levels are frequently elevated in patients following cardiac surgery.
• The six-minute walking test (6MWT) is a key assessment for functional capacity in this patient group.

Purpose of the Study:

• To investigate the association between plasma BNP levels and exercise capacity, evaluated by 6MWT, in patients after cardiac surgery.

Main Methods:

• 101 patients undergoing cardiac surgery had plasma BNP measured and underwent 6MWT approximately 8 days post-operation.
• Potential predictors of reduced 6MWT performance (percentage of predicted values) included demographics, comorbidities, echocardiographic parameters (LVEF, E/E', iLAV), and plasma BNP levels.

Main Results:

• 6MWT performance averaged 65% of predicted values, independent of LVEF, E/E', or iLAV.
• Female sex and atrial fibrillation were associated with significantly reduced exercise capacity.
• Plasma BNP levels showed an inverse correlation with 6MWT performance (r = -0.25, P = 0.010).
• Multivariate analysis identified female sex, atrial fibrillation, and BNP levels as independent predictors of reduced exercise capacity.

Conclusions:

• Increased plasma BNP levels in postcardiac surgery patients are significantly associated with diminished exercise capacity.
• BNP may serve as a valuable biomarker for assessing functional recovery and predicting exercise limitations after cardiac surgery.